JP2009030720A - Vent valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vent valve easy to operate and construct and inexpensive to manufacture for preventing the whirling-up of particles in a vacuum chamber and the degradation of throughput. <P>SOLUTION: A valve element 21 is provided in an internal space 12 of a casing 11, and the valve element 21 is energized toward its fully opened position by a spring 31. An air cylinder 51 is provided for displacing the valve element 21 toward its closed position against the spring 31. When the valve element 21 is at the closed position and a through-hole 24 is closed, an inlet passage 16 is cut off from an output passage 17, and when the through-hole 24 is opened, it is communicated therewith. Except at the closed position, the inlet passage 16 is communicated with the outlet passage 17 via the through-hole 24 and a tapered groove 13 in an inner face 11a of the casing 11. The cross section area of the tapered groove 13 is increased with an increase in the displacement of the valve element 21 from the closed position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vent valve, and more specifically, various vacuum devices (for example, a CVD (Chemical Vapor Deposition) device, a PVD (Physical Vapor Deposition) device, a vacuum deposition) used in a manufacturing process of a semiconductor device, a liquid crystal display device, and the like. In an apparatus, a plasma etching apparatus, etc., a gas (air or inert gas) is introduced into a vacuum chamber in a vacuum (negative pressure) state, and the pressure in the vacuum chamber is substantially equal to the atmospheric pressure from the vacuum state ( The present invention relates to a vent valve that is preferably used to control the flow rate (flow state) of the gas when returning to the atmospheric pressure state.

  In the manufacturing process of a semiconductor device, the pressure in the vacuum chamber is often set to a predetermined vacuum (negative pressure) state or an atmospheric pressure state. For example, in the load lock chambers provided on the semiconductor wafer carry-in side and the semiconductor wafer carry-out side of the plasma etching apparatus, gas (for example, nitrogen gas or air) is introduced and set to an atmospheric pressure state when the semiconductor wafer is carried. Then, when the semiconductor wafer is carried in from the outside of the load lock chamber under the atmospheric pressure state, and then the gas in the load lock chamber is exhausted to reach a predetermined vacuum state, the semiconductor wafer is carried out of the load lock chamber. Then, it is moved to an etching process chamber maintained in a predetermined vacuum state. When the unloading of the semiconductor wafer is completed, the gas is again introduced into the load lock chamber and the atmospheric pressure state is set. In this state, the semiconductor wafer is loaded from the outside. When the loading is completed, the gas in the load lock chamber is discharged again to be in a predetermined vacuum state, and the semiconductor wafer is unloaded from the load lock chamber in this state and transferred to the etching processing chamber. As described above, the vacuum chamber is switched between the vacuum state and the atmospheric pressure state many times each time the semiconductor wafer is carried in / out.

  As described above, the load-lock chamber is switched between the vacuum state and the atmospheric pressure state so that the etching chamber having a larger volume than the load-lock chamber can always be maintained in a predetermined vacuum state. This is because the throughput is improved as compared with the case of switching between the atmospheric pressure state and the vacuum state.

  By the way, when introducing gas into the load lock chamber in a vacuum state, for example, when nitrogen gas is used, a container filled with nitrogen gas (that is, a nitrogen gas supply source) (the pressure thereof is made equal to the atmospheric pressure). ) Is connected to the load lock chamber via an appropriate valve, and when the atmosphere is used, the load lock chamber is communicated with air (atmosphere) via an appropriate valve (that is, released to the atmosphere). In that case, since the difference between the pressure (atmospheric pressure) on the gas supply source side and the pressure in the load lock chamber is large at the initial stage of introduction, if a valve having a constant flow path cross-sectional area such as a needle valve is used, nitrogen gas or Air (hereinafter referred to as “gas” including both) flows at a high flow rate and a large flow rate. When the pressure in the load lock chamber increases due to the inflow of gas, the pressure difference from the gas supply source side gradually decreases, and accordingly, the gas flow rate gradually decreases and the flow rate decreases accordingly. For this reason, in the initial stage of introduction, particles (fine dust) staying at the bottom and side walls in the load lock chamber are easily rolled up. When the particles are wound up in this way, the etching process cannot be started until the particles stay again, so that the yield of the etching process is reduced by introducing a high flow rate and a large flow rate of gas.

  To suppress or reduce the rolling-up of particles in the initial stage of gas introduction, the gas flow rate can be reduced and the flow rate can be reduced, but doing so reduces the throughput because it takes a very long time to reach atmospheric pressure. Connected. Therefore, a method has been proposed in which the gas flow rate is reduced in the initial stage of introduction and then increased, thereby preventing the particles from rolling up in the load lock chamber and at the same time preventing the decrease in throughput (Patent Document). 1 (see JP-A-3-283612).

  In order to realize this method, Patent Document 1 uses a leak valve having the following configuration. That is, a valve main body having a gas flow path therein, a plunger provided in the middle of the gas flow path, and a coil mounted on the outside of the gas flow path so as to surround the gas flow path, The leak valve is configured to change the size of the gap of the gas flow path by displacing the plunger along the gas flow path by using an electromagnetic force generated by supplying current. According to this leak valve, by adjusting the amount of current supplied to the coil, the amount of displacement of the plunger changes and the size of the gap changes, so the flow rate of gas passing through the gas flow path at the initial stage of introduction It is possible to control such that the flow rate is reduced and then increased, and the flow rate is reduced again at the end of the introduction.

  In addition, although the said description has described the vacuum chamber of the plasma etching apparatus used in the manufacturing process of a semiconductor device, it cannot be overemphasized that it applies similarly also about arbitrary vacuum apparatuses other than that.

  As other valves that enable the flow rate control as described above, there are a throat vent valve disclosed in Patent Document 2 (Patent No. 2582993) and a throat vent disclosed in Patent Document 3 (Patent No. 2852843). There is a valve and a vacuum exhaust valve disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 7-145872).

  The slow vent valve of Patent Document 2 is “provided in a pipe line that communicates a sealed container that is evacuated by a vacuum pump and a gas supply source, and supplies gas into the sealed container in a vacuum state to atmospheric pressure. A leak valve having a leak valve and valve opening control means for gradually changing the valve opening of the leak valve to a predetermined opening as time elapses after energization of the leak valve is started. And a gas open / close valve attached to a pipeline between the gas supply source and the leak valve is a normally open type leak valve (refer to claim 1). . In other words, this slow vent valve is a normally open type in which the valve opening degree is gradually changed to a predetermined opening degree by the valve opening degree control means on the pipe line connecting the sealed container (vacuum chamber) and the gas supply source. A leak valve and a gas on-off valve are provided in combination (see FIGS. 1 and 4).

  In the slow vent valve disclosed in Patent Document 2, when the gas is introduced, the leak valve is first fully closed, and then the gas on-off valve is fully opened after 1 to 2 seconds have elapsed. Thereafter, the leak valve is energized so as to have a predetermined opening in a predetermined time, and then the opening is maintained. When it is detected that the pressure in the sealed container (vacuum chamber) has become atmospheric pressure, the leak valve is fully opened and the gas on-off valve is fully closed. In this way, by reducing the gas flow rate at the initial stage of introduction and then increasing the gas flow rate, it is possible to prevent the particles from being rolled up and the throughput from being lowered in the load lock chamber.

  The slow vent valve disclosed in Patent Document 3 is a "normally closed type metal diaphragm valve. The actuator that operates the valve rod that pushes the metal diaphragm is composed of a valve full-open cylinder and a slow leak cylinder. Has a built-in piston integrated on the middle outer periphery of the valve stem and a spring that urges the piston toward the metal diaphragm. The slow leak cylinder is connected to the valve fully open valve. A leakage piston which is slidably provided on the outer periphery of the upper end of the rod and is secured to a retaining ring fixed to the upper end of the valve stem, a cap-shaped cam receiving base provided on the leakage piston, and the cam A cam disposed on the receiving base so as to be swingable up and down, and engages with a tip of the cam so that the leakage piston is A spring for urging the tal diaphragm side, a swing fulcrum ball of the cam, an adjuster for moving the swing fulcrum ball forward and backward, and an adjustment knob for pressing the top end of the cam. "Slow vent valve" (see claim 1).

  In the slow vent valve of Patent Document 3, when the gas is introduced, first, compressed air is supplied to the slow leak cylinder to displace the leak piston, so that the metal diaphragm is slightly opened. Thus, the gas is slowly leaked into the vacuum chamber. When the pressure in the vacuum chamber rises to 200 to 400 Torr, compressed air is supplied to the valve fully opening cylinder to displace the piston, so that the valve rod integrated with the piston contacts the cam receiving base. Displace until it comes into contact, so that the slow vent valve is fully opened. Thus, gas is introduced into the vacuum chamber until atmospheric pressure is reached (see paragraph 0007). In this way, by reducing the gas flow rate at the initial stage of introduction and then increasing the gas flow rate, it is possible to prevent the particles from being rolled up and the throughput from being lowered in the vacuum chamber.

  The vacuum exhaust valve disclosed in Patent Document 4 is “a vacuum exhaust valve attached to a vacuum exhaust pipe path connecting a vacuum chamber and a vacuum exhaust pump, and the valve has a pipe corresponding to a flow rate of gas flowing in the vacuum exhaust pipe. An evacuation valve characterized in that it is provided with means for varying the path resistance (see claim 1). The variable means preferably includes a movable shielding plate having a through hole and a spring for holding the shielding plate (see claim 2). Preferably, the inner cavity portion has an inner wall such that a gap between the inner cavity portion and the shielding plate is gradually reduced as the spring holding the shielding plate contracts (see claim 3). .

  As is apparent from the description of claim 1, the vacuum exhaust valve of Patent Document 4 is attached to a path connecting the vacuum chamber (vacuum chamber) and the vacuum exhaust pump. Controls the flow rate of the exhausted gas. On the other hand, the above-described leak valve of Patent Document 1 and the throat vent valve of Patent Documents 2 and 3 are attached to a path connecting the vacuum chamber and the gas supply source, and are supplied (introduced) to the vacuum chamber. Control the flow rate of the gas. Therefore, the valve of Patent Document 4 is clearly different from the valves of Patent Documents 1 to 3 in this respect.

  Furthermore, as another prior art that enables the flow rate control as described above, there is a method shown in FIG. In the method of FIG. 12, an air supply pipe 103 for supplying gas to a vacuum chamber (for example, a load lock chamber) 101 is branched into a first branch pipe 103a and a second branch pipe 103b, and the first branch pipe 103a A large-diameter vent valve 104a is installed, and a small-diameter vent valve 104b is installed in the second branch pipe 103b. An inert gas is introduced into the vacuum chamber 101 through one (or both) of the first branch pipe 103a and the second branch pipe 103b.

  In the vacuum chamber 101, an exhaust pipe 107 is further installed on the opposite side of the air supply pipe 103. Connected to the end of the exhaust pipe 107 is a vacuum pump 106 for discharging a gas existing inside the vacuum chamber 101 to generate a desired vacuum state. A vacuum valve 105 for controlling the flow rate of the gas discharged from the exhaust pipe 107 is installed in the middle of the exhaust pipe 107. Reference numeral 102 denotes a work (for example, a semiconductor wafer) placed in the vacuum chamber 101.

  In the configuration of FIG. 12, until the pressure in the vacuum chamber 101 reaches, for example, 30 kPa, only the small-diameter vent valve 104b is opened, and gas is introduced into the vacuum chamber 101 only through the second branch pipe 103b. Thereafter, the small-diameter vent valve 104b is closed (or the small-diameter vent valve 104b is kept open), and the large-diameter vent valve 104a is opened and only through the first branch pipe 103a (or the first branch pipe 103a and the first branch pipe 103a). Gas is introduced into the vacuum chamber 101 (through both of the two branch tubes 103b). As described above, the gas is introduced into the vacuum chamber 101 while changing the flow rate stepwise by using the two vent valves 104a and 104b having different diameters (flow rates).

As described above, in order to change the vacuum state to the atmospheric pressure state in a short time while suppressing the rolling-up of particles, it is preferable to continuously change the gas flow rate at the initial stage of introduction and thereafter. However, since it is not easy to realize it with a single vent valve, the method of FIG. 12 is adopted. Therefore, this method is intended to realize flow rate control similar to this by combining two vent valves 104a and 104b having different flow rates for convenience.
JP-A-3-283612 Japanese Patent No. 2582993 Japanese Patent No. 2852843 Japanese Patent Laid-Open No. 7-145872

  The leak valve disclosed in Patent Document 1 adjusts the amount of displacement of the plunger arranged in the gas flow path by using the electromagnetic force generated by the current supply to the coil, thereby reducing the size of the gap in the gas flow path. Since the change is made, the control of the displacement amount of the plunger (the size of the gap of the gas flow path) is not stable. Also, it is not easy to precisely control the electromagnetic force so that the plunger has a desired displacement amount by controlling the amount of current supplied to the coil. For this reason, there exists a problem that it is not easy to implement | achieve the flow control described in the literature using the leak valve of patent document 1. FIG.

  The slow vent valve of Patent Document 2 can realize the flow rate control described in Patent Document 1, but has a structure combining a normally open type leak valve and a gas on-off valve. There is a problem that it is complicated and the manufacturing cost is high.

  The slow vent valve of Patent Document 3 can realize the flow control described in Patent Document 1, but in a normally closed type metal diaphragm valve, an actuator that operates a valve rod that pushes the metal diaphragm is used as a valve. Since it is composed of a fully open cylinder and a slow leak cylinder, there is a problem that the structure is complicated and the manufacturing cost is high, as in the slow vent valve of Patent Document 2.

  The vacuum exhaust valve of Patent Document 4 has a simpler configuration than the slow vent valves of Patent Documents 2 and 3, but this vacuum exhaust valve is connected to a vacuum chamber (vacuum chamber) and a vacuum exhaust pump. It is attached and used to evacuate the vacuum chamber, and cannot be attached to a path connecting the vacuum chamber and the gas supply source.

  In the conventional method shown in FIG. 12, the supply pipe 103 to the vacuum chamber 101 is branched into a first branch pipe 103a and a second branch pipe 103b, and a large-diameter vent valve is connected to the first branch pipe 103a and the second branch pipe 103b. It is necessary to install 104a and a small-diameter vent valve 104b, respectively, and to control the opening and closing of the vent valves 104a and 104b as described above. For this reason, not only is the operation complicated, but two vent valves 104a and 104b having different diameters are required for one vacuum chamber 101, and the cost for carrying out the method is high. There is.

  The present invention has been made in view of such circumstances in the prior art. The object of the present invention is to introduce a gas into the vacuum chamber and change the state in the vacuum chamber from a vacuum (negative pressure) state to a large amount. When returning to the atmospheric pressure state, the gas flow rate can be controlled to realize both prevention of particle rolling-up and reduction in throughput, as well as simple operation and configuration and low manufacturing cost. To provide a valve.

  Other objects of the present invention which are not specified here will be apparent from the following description and the accompanying drawings.

(1) The vent valve according to the first aspect of the present invention is:
A vent valve used to introduce gas into the vacuum chamber and return the pressure in the vacuum chamber from a vacuum state to an atmospheric pressure state;
A casing having an inlet passage and an outlet passage;
An internal space formed inside the casing for connecting the inlet passage and the outlet passage;
A valve body disposed in the internal space so as to be displaceable between a predetermined closed position and a predetermined fully open position;
Biasing means for biasing the valve body toward the fully open position by an elastic force;
An actuator for displacing the valve body toward the closed position against the elastic force of the biasing means,
The valve body has a through hole communicating with the inlet passage and the outlet passage in the internal space, and the through hole can be closed by the actuator.
When the valve body is in the closed position and the through hole is closed by the actuator, communication between the inlet passage and the outlet passage is blocked,
When the valve body is in the closed position and the through hole is not closed by the actuator, the inlet passage and the outlet passage communicate with each other through the through hole,
When the valve body is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole, and an opening is generated between the inner surface of the casing and the valve body,
The cross-sectional area of the opening is increased according to an increase in the amount of displacement of the valve body from the closed position.

  Since the vent valve according to the first aspect of the present invention has the above-described configuration, the valve body is disposed at the closed position against the elastic force of the urging means by the actuator, and the valve body When the through hole is closed by the actuator, the communication between the inlet passage and the outlet passage is blocked. Therefore, in this state, even if gas is introduced into the internal space from the inlet passage, the gas does not reach the outlet passage. That is, no gas is introduced into the vacuum chamber connected to the outlet passage.

  When the valve body is in the closed position, when the actuator is operated to open the through hole of the valve body, the inlet passage and the outlet passage communicate with each other through the through hole. The gas introduced into the internal space can reach the outlet passage at a flow rate corresponding to the cross-sectional area of the through hole. At this time, since the inside of the vacuum chamber connected to the outlet passage is in a vacuum state, the valve body moves toward the closed position by the pressure of the gas introduced into the internal space (this is equal to the atmospheric pressure). The valve body is pressed against the elastic force of the biasing means, and the valve body is held in the closed position by the pressing force. Therefore, by adjusting the cross-sectional area of the through-hole to an appropriate value, the introduction of gas at a low flow rate required at the beginning of introduction is realized, and the rolling-up of particles in the vacuum chamber is reduced or prevented. Can do.

  Thus, when the gas starts to be introduced into the vacuum chamber, the pressure in the vacuum chamber gradually rises with the introduction of the gas, so that the pressure in the outlet passage also rises, and the pressing force acting on the valve body ( This is gradually increasing). When the sum of the pressing force due to the gas in the outlet passage and the elastic force of the urging means becomes larger than the pressing force due to the gas in the inlet passage, the valve body is disengaged from the closed position and displaced toward the fully open position. Begin. The amount of displacement of the valve body at this time is such that the sum of the pressing force by the gas in the outlet passage and the elastic force of the urging means is kept equal to the pressing force by the gas in the inlet passage. It increases as the amount of gas introduced into the chamber increases.

  While the valve body is out of the closed position and is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole of the valve body, and the inner surface of the casing and the valve The opening is created between the body. For this reason, the gas in the inlet passage flows to the outlet passage through the through hole and the opening, that is, the total flow rate of the gas increases by an amount corresponding to the cross-sectional area of the opening. Here, since the cross-sectional area of the opening increases as the displacement of the valve body from the closed position increases, the total flow rate of the gas increases with an increase of the displacement of the valve body. Will increase. As a result, as soon as the valve body moves out of the closed position (after the initial introduction), the total gas flow rate increases by an amount corresponding to the cross-sectional area of the opening, and thereafter the displacement amount of the valve body increases. As it increases, it is gradually increased automatically. Thus, immediately after the end of the introduction, gas starts to be introduced into the vacuum chamber at a flow rate increased from the beginning of the introduction, thereby preventing a reduction in throughput.

  As the pressure in the vacuum chamber rises further, the pressure in the outlet passage rises accordingly, and the pressure difference between the inlet passage and the outlet passage decreases, so that the elastic force of the biasing means is reduced. The effect increases and the displacement of the valve body further increases. Thus, the valve body approaches the fully opened position. During this time, the cross-sectional area of the opening generated between the inner surface of the casing and the valve body increases as the displacement amount of the valve body increases. If the cross-sectional area of the opening is fixed (unchangeable) during this period, the gas flow rate is significantly reduced due to the reduction in the pressure difference between the inlet passage and the outlet passage, and the time until the atmospheric pressure state is reached. Long and easy to reduce throughput. On the other hand, in this vent valve, since the cross-sectional area of the opening increases as the displacement of the valve element increases, the gas flow rate decreases due to the decrease in the pressure difference between the inlet passage and the outlet passage. As a result, a decrease in throughput is prevented or alleviated. During this period (that is, between the beginning of introduction and the end of introduction), the total gas flow rate and its change are the difference in pressure between the inlet passage and the outlet passage, the sectional area of the opening, and the sectional area of the through hole. Since it is determined by the relationship between the three, it is only necessary to appropriately set those values as necessary so that a desired total flow rate can be obtained.

  At the end of introduction, there is almost no pressure difference between the inlet passage and the outlet passage, and the valve element is caused to reach the fully open position by the elastic force of the biasing means. At this time, the sectional area of the opening is maximized. At the end of introduction, the through hole may be closed or may remain open. However, since the cross-sectional area of the through hole is considerably smaller than the cross-sectional area of the opening, the through-hole is not closed or opened. The effect on gas flow rate is small. For this reason, it can be said that the gas flow rate at this time is determined by the pressure difference between the inlet passage and the outlet passage and the sectional area of the opening.

  As is apparent from the above description, according to the vent valve of the first aspect of the present invention, gas is introduced into the vacuum chamber, and the state in the vacuum chamber is changed from a vacuum (negative pressure) state to an atmospheric pressure state. When returning to the above, it is possible to control both the flow of the gas and prevent the particles in the vacuum chamber from rolling up and the throughput from decreasing.

  In the vent valve according to the first aspect of the present invention, the valve body is disposed in the inner space of the casing so as to be displaceable between the closed position and the fully opened position, and the elastic force of the biasing means is provided. The valve body is urged toward the fully open position by the above, and the valve body is displaced toward the closed position by the actuator. Therefore, the configuration of the vent valve is simple. In addition, any of these components does not require special properties and functions, and does not require special processing, so that the manufacturing cost of the vent valve can be reduced.

  Further, the valve body is displaced using the actuator and the through-hole is opened and closed, so that the gas is introduced into the vacuum chamber through the through-hole in the initial stage of introduction to keep the total gas flow rate small. ing. Immediately after the initial stage of introduction, the valve body is displaced using a pressure difference between the inlet passage and the outlet passage, thereby generating the opening between the inner surface of the casing and the valve body, The total gas flow rate is increased by an amount corresponding to the cross-sectional area of the opening. In addition, during the period from the beginning of introduction to the end of introduction, the inlet passage and the outlet passage are configured such that the cross-sectional area of the opening increases in accordance with an increase in the displacement amount of the valve body due to the pressure difference. The reduction of the gas flow rate due to the reduction of the pressure difference with the gas is alleviated. In this way, if only the displacement of the valve element and the opening / closing of the through hole are performed at the initial stage of introduction, all other operations are automatically performed, so that the operation of the vent valve is simple.

  Therefore, the vent valve according to the first aspect of the present invention controls the flow rate of the gas when the gas is introduced into the vacuum chamber and the state in the vacuum chamber is returned from the vacuum (negative pressure) state to the atmospheric pressure state. Thus, it is possible to realize both the prevention of particle rolling-up and the reduction of the throughput in the vacuum chamber, the operation and configuration are simple, and the manufacturing cost is low.

  (2) In a preferred example of the vent valve according to the first aspect of the present invention, at least one taper groove is formed on the inner surface of the casing, and the valve body is in a position other than the closed position. The opening formed between the inner surface of the casing and the valve body is formed by a gap generated between the inner surface of the casing and the valve body by the at least one tapered groove.

  In this example, there is an advantage that the cross-sectional area of the opening can be increased continuously with an increase in the amount of displacement of the valve body, and the processing for forming the opening is easy. In addition, there is an advantage that an increase in the cross-sectional area of the opening can be easily adjusted by changing the width, depth, taper angle, or the total number of the tapered grooves of the at least one tapered groove.

  (3) In another preferred example of the vent valve according to the first aspect of the present invention, the entire inner surface of the casing is tapered, and the casing is in a position other than the closed position. The opening formed between the inner surface of the casing and the valve body is formed by a gap generated between the inner surface of the casing and the valve body.

  In this example, since the opening is formed over the entire inner wall surface of the casing, not only can the change in the cross-sectional area of the opening accompanying the displacement of the valve body be continuous, but also the displacement of the valve body. There is an advantage that the change in the cross-sectional area of the opening can be easily enlarged.

(4) In still another preferred example of the vent valve according to the first aspect of the present invention, the actuator has a drive member configured to be able to protrude into the internal space, and the drive member is disposed in the internal space. The valve body is configured to be displaced toward the closed position by protruding into the space and contacting the valve body,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed in the closed position;
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully opened position independently of the drive member.

  In this example, there is an advantage that a known air cylinder can be used as the actuator and the rod can be used as the driving member.

(5) In still another preferred example of the vent valve according to the first aspect of the present invention, the actuator has a drive member configured to be able to protrude into the internal space, and the drive member is disposed in the internal space. The valve body is configured to be displaced toward the closed position by protruding into the space and contacting the valve body,
The through hole of the valve body is closed by pressing a sealing material attached to the driving member against the through hole.

  In this example, there is an advantage that a known air cylinder is used as the actuator, the rod can be used as the drive member, and the through hole can be easily opened and closed.

(6) In still another preferred example of the vent valve according to the first aspect of the present invention, the actuator has a drive member configured to be able to protrude into the internal space, and the drive member is the valve. The valve body is configured to be displaced toward the closed position by projecting into the internal space along the direction in which the body is displaced and contacting the valve body,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed to the closed position, and the through hole of the valve body is formed by a sealing material attached to the drive member. Closed,
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully open position independently of the drive member;
The position where the valve body abuts on the drive member when the drive member is in the predetermined retracted position is the fully open position.

  In this example, there is an advantage that a known air cylinder is used as the actuator, the rod can be used as the driving member, and the through hole can be opened and closed easily and reliably.

  (7) In still another preferred example of the vent valve according to the first aspect of the present invention, the actuator is an air cylinder, and the driving member of the actuator is a rod of the air cylinder.

  In this example, since a general-purpose air cylinder may be used, there are advantages that the configuration of the actuator is simplified and the manufacturing cost can be easily reduced.

(8) The vent valve according to the second aspect of the present invention is:
A vent valve used to introduce gas into the vacuum chamber and return the pressure in the vacuum chamber from a vacuum state to an atmospheric pressure state;
A casing having an inlet passage and an outlet passage;
An internal space formed inside the casing for connecting the inlet passage and the outlet passage;
A valve body disposed in the internal space so as to be displaceable between a predetermined closed position and a predetermined fully open position;
Biasing means for biasing the valve body toward the fully open position by an elastic force;
An actuator for displacing the valve body toward the closed position against the elastic force of the biasing means,
The valve body has a through hole communicating with the inlet passage and the outlet passage in the internal space, and the through hole can be closed by the actuator.
When the valve body is in the closed position and the through hole is closed by the actuator, communication between the inlet passage and the outlet passage is blocked,
When the valve body is in the closed position and the through hole is not closed by the actuator, the inlet passage and the outlet passage communicate with each other through the through hole,
When the valve body is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole, and an opening that penetrates the casing and communicates with the outside is generated.
The cross-sectional area of the opening is increased according to an increase in the amount of displacement of the valve body from the closed position.

  The vent valve according to the second aspect of the present invention has substantially the same configuration as the vent valve according to the first aspect of the present invention described above, and when the valve body is in a position other than the closed position, Instead of “the opening is generated between the inner surface and the valve body”, only “the opening that passes through the casing and communicates with the outside is generated” is different.

  That is, since the vent valve according to the second aspect of the present invention has the above-described configuration, the valve body is disposed in the closed position against the elastic force of the biasing means by the actuator, When the through hole of the valve body is closed by the actuator, the communication between the inlet passage and the outlet passage is blocked. Therefore, in this state, even if gas is introduced into the internal space from the inlet passage, the gas does not reach the outlet passage. That is, no gas is introduced into the vacuum chamber connected to the outlet passage. This is the same as the vent valve according to the first aspect of the present invention.

  When the valve body is in the closed position, when the actuator is operated to open the through hole of the valve body, the inlet passage and the outlet passage communicate with each other through the through hole. The gas introduced into the internal space can reach the outlet passage at a flow rate corresponding to the cross-sectional area of the through hole. At this time, since the inside of the vacuum chamber connected to the outlet passage is in a vacuum state, the valve body moves toward the closed position by the pressure of the gas introduced into the internal space (this is equal to the atmospheric pressure). The valve body is pressed against the elastic force of the biasing means, and the valve body is held in the closed position by the pressing force. Therefore, by adjusting the cross-sectional area of the through-hole to an appropriate value, introduction of gas at a low flow rate and low flow rate required at the initial stage of introduction is realized, and particle rolling up in the vacuum chamber is reduced or Can be prevented. This is also the same as the vent valve according to the first aspect of the present invention.

  Thus, when the gas starts to be introduced into the vacuum chamber (after the initial stage of introduction), the pressure in the vacuum chamber gradually increases with the introduction of the gas, so that the pressure in the outlet passage also increases, and the valve body The pressing force acting on (which is toward the fully open position) gradually increases. When the sum of the pressing force due to the gas in the outlet passage and the elastic force of the urging means becomes larger than the pressing force due to the gas in the inlet passage, the valve body is disengaged from the closed position and displaced toward the fully open position. Begin. The amount of displacement of the valve body at this time is such that the sum of the pressing force by the gas in the outlet passage and the elastic force of the urging means is kept equal to the pressing force by the gas in the inlet passage. It increases as the amount of gas introduced into the chamber increases. This is also the same as the vent valve according to the first aspect of the present invention.

  While the valve body is out of the closed position and is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole of the valve body, and “through the casing” The "opening" that communicates with the outside is generated. For this reason, the gas in the inlet passage flows to the outlet passage through the through hole, and also flows from the outside of the casing to the outlet passage through the opening. Here, for example, by placing the casing (the vent valve) in the gas atmosphere (for example, in the air) so that the gas (for example, air) can be supplied from the outside of the casing, the gas The total flow rate increases by an amount corresponding to the cross-sectional area of the opening. As a result, as soon as the valve body moves out of the closed position (after the initial introduction), the total gas flow rate increases by an amount corresponding to the cross-sectional area of the opening, and thereafter the displacement amount of the valve body increases. As it increases, it is gradually increased automatically. Thus, immediately after the end of the introduction, gas starts to be introduced into the vacuum chamber at a flow rate increased from the beginning of the introduction, thereby preventing a reduction in throughput. This point is slightly different from the vent valve according to the first aspect of the present invention.

  As the pressure in the vacuum chamber rises further, the pressure in the outlet passage rises accordingly, and the pressure difference between the inlet passage and the outlet passage decreases, so that the elastic force of the biasing means is reduced. The effect increases and the displacement of the valve body further increases. Thus, the valve body approaches the fully opened position. During this time, the cross-sectional area of “the opening that passes through the casing and communicates with the outside” increases as the displacement of the valve element increases. If the cross-sectional area of the opening is fixed (unchangeable) during this period, the gas flow rate is significantly reduced due to the reduction in the pressure difference between the inlet passage and the outlet passage, and the time until the atmospheric pressure state is reached. Long and easy to reduce throughput. On the other hand, in this vent valve, since the cross-sectional area of the opening increases as the displacement of the valve element increases, the gas flow rate decreases due to the decrease in the pressure difference between the inlet passage and the outlet passage. As a result, a decrease in throughput is prevented or alleviated. During this period (that is, between the beginning of introduction and the end of introduction), the total gas flow rate and its change are the difference in pressure between the inlet passage and the outlet passage, the sectional area of the opening, and the sectional area of the through hole. Since it is determined by the relationship between the three, it is only necessary to appropriately set those values as necessary so that a desired total flow rate can be obtained.

  At the end of introduction, there is almost no pressure difference between the inlet passage and the outlet passage, and the valve element is caused to reach the fully open position by the elastic force of the biasing means. At this time, the sectional area of the opening is maximized. At the end of introduction, the through hole may be closed or may remain open. However, since the cross-sectional area of the opening is considerably smaller than the cross-sectional area of the opening, the through-hole is not closed or opened. The effect on gas flow rate is small. For this reason, it can be said that the gas flow rate at this time is determined by the pressure difference between the inlet passage and the outlet passage and the sectional area of the opening.

  As is apparent from the above description, according to the vent valve of the second aspect of the present invention, as in the vent valve according to the first aspect of the present invention, gas is introduced into the vacuum chamber and When the internal state is returned from the vacuum (negative pressure) state to the atmospheric pressure state, it is possible to control both the flow rate of the gas and prevent the particles from being rolled up and the throughput from being lowered.

  In the vent valve according to the second aspect of the present invention, the valve body is disposed in the internal space of the casing so as to be displaceable between the closed position and the fully opened position, and the elastic force of the biasing means is provided. The valve body is urged toward the fully open position by the above, and the valve body is displaced toward the closed position by the actuator, and the through hole of the valve body is closed. The configuration of the vent valve is simple. In addition, any of these components does not require special properties and functions, and does not require special processing, so that the manufacturing cost of the vent valve can be reduced.

  Further, the valve body is displaced using the actuator and the through-hole is opened and closed, so that the gas is introduced into the vacuum chamber through the through-hole in the initial stage of introduction to keep the total gas flow rate small. ing. Immediately after the initial stage of introduction, the valve body is displaced using the pressure difference between the inlet passage and the outlet passage, thereby generating the opening that penetrates the casing and communicates with the outside. The total gas flow rate is increased by an amount corresponding to the cross-sectional area of the opening. In addition, during the period from the beginning of introduction to the end of introduction, the inlet passage and the outlet passage are configured such that the cross-sectional area of the opening increases in accordance with an increase in the displacement amount of the valve body due to the pressure difference. The reduction of the gas flow rate due to the reduction of the pressure difference with the gas is alleviated. In this way, if only the displacement of the valve element and the opening / closing of the through hole are performed at the initial stage of introduction, all other operations are automatically performed, so that the operation of the vent valve is simple.

  Therefore, the vent valve according to the second aspect of the present invention introduces a gas into the vacuum chamber to change the state in the vacuum chamber from the vacuum (negative pressure) state, similarly to the vent valve according to the first aspect of the present invention. When returning to atmospheric pressure, the flow rate of the gas can be controlled to prevent both the particles from being rolled up and the throughput from being lowered, and the operation and configuration are simple and the manufacturing cost is low. It is.

  (9) In a preferred example of the vent valve according to the second aspect of the present invention, the casing has a plurality of through holes that pass through the casing and are spaced along the direction in which the valve body is displaced. The opening generated when the valve body is at a position other than the closed position is formed by at least one of the plurality of through holes.

  In this example, the change in the cross-sectional area of the opening accompanying the displacement of the valve body becomes stepwise, but it is only necessary to open a plurality of through holes at a predetermined position of the casing. Has the advantage of being very easy. In addition, there is an advantage that the increasing state of the cross-sectional area of the opening can be easily adjusted by changing the diameter, number, interval, or the total number of the through holes.

(10) In another preferable example of the vent valve according to the second aspect of the present invention, the actuator includes a drive member configured to be able to protrude into the internal space, and the drive member is disposed in the internal space. The valve body is configured to be displaced toward the closed position by causing the valve body to protrude into contact with the valve body,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed in the closed position;
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully opened position independently of the drive member.

  In this example, there is an advantage that a known air cylinder can be used as the actuator and the rod can be used as the driving member.

(11) In still another preferable example of the vent valve according to the second aspect of the present invention, the actuator has a drive member configured to be able to protrude into the internal space, and the drive member is disposed in the internal space. The valve body is configured to be displaced toward the closed position by protruding into the space and contacting the valve body,
The through hole of the valve body is closed by pressing a sealing material attached to the driving member against the through hole.

  In this example, there is an advantage that a known air cylinder is used as the actuator, the rod can be used as the drive member, and the through hole can be easily opened and closed.

(12) In still another preferred example of the vent valve according to the second aspect of the present invention, the actuator has a drive member configured to be able to protrude into the internal space, and the drive member is the valve. The valve body is configured to be displaced toward the closed position by projecting into the internal space along the direction in which the body is displaced and contacting the valve body,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed to the closed position, and the through hole of the valve body is formed by a sealing material attached to the drive member. Closed,
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully open position independently of the drive member;
The position where the valve body abuts on the drive member when the drive member is in the predetermined retracted position is the fully open position.

  In this example, there is an advantage that a known air cylinder is used as the actuator, the rod can be used as the driving member, and the through hole can be opened and closed easily and reliably.

  (13) In still another preferred example of the vent valve according to the second aspect of the present invention, the actuator is an air cylinder, and the driving member of the actuator is a rod of the air cylinder.

  In this example, since a general-purpose air cylinder may be used, there are advantages that the configuration of the actuator is simplified and the manufacturing cost can be easily reduced.

  (14) In the vent valve according to the first and second aspects of the present invention, the “vacuum chamber” is a chamber (chamber) in which gas can be introduced / exhausted as required to set the inside to a vacuum state or an atmospheric pressure state. ) And its shape and configuration are arbitrary.

As the “gas” introduced into the vacuum chamber, for example, the atmosphere (air) or an inert gas such as nitrogen (N ₂ ) is often used, but the present invention is not limited to these and other gases can also be used. It is.

  The “casing” forms an outer jacket of the vent valve, and may have an inlet passage and an outlet passage and an internal space connecting them, and the configuration and shape thereof are arbitrary.

  The “internal space” can be formed in any shape as long as it is formed inside the casing and connects the inlet passage and the outlet passage and can displace the valve body therein.

  The shape and configuration of the “valve element” are not particularly limited. It suffices if the inner space can be displaced between a predetermined closed position and a predetermined fully opened position by the elastic force of the biasing means and the gas pressure.

  The “biasing means” may have any configuration or material as long as it biases the valve body toward the fully open position by an elastic force. Preferably, the spring has an elastic force that urges the valve body toward the fully open position, but the shape of the spring can be arbitrarily set such as a spiral shape or a plate shape.

  Any “actuator” may be used as long as it can displace the valve body toward the closed position against the elastic force of the urging means. Preferably, an air cylinder is used, but other cylinders such as an electric cylinder can also be used.

  According to the first and second aspect vent valves of the present invention, when the gas is introduced into the vacuum chamber and the state in the vacuum chamber is returned from the vacuum (negative pressure) state to the atmospheric pressure state, the flow rate of the gas It is possible to achieve both the prevention of the particle rolling-up and the reduction in the throughput by controlling the above, and the operation and configuration are simple and the manufacturing cost is low.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

(Configuration of the first embodiment)
FIG. 1 is a cross-sectional view of an essential part showing the configuration of the vent valve 1 according to the first embodiment of the present invention, and FIG. Since the internal structure of the air cylinder is well known and not important, only the main body is shown in cross section in FIG. 1, and the air cylinder is an external view. The vent valve 1 corresponds to the vent valve according to the first aspect of the present invention.

  The vent valve 1 of 1st Embodiment is comprised from the main-body part 10 and the drive part 50 for driving the main-body part 10, as shown in FIG.

  In the first embodiment, the drive unit 50 is composed of an air cylinder 51. By supplying / discharging compressed air from supply / exhaust ports 54 and 55 provided at the upper and lower ends of the drive unit 50, a predetermined extension position is provided. The rod 52 can be moved in the vertical direction between the predetermined retracted position. As will be described later, the rod 52 can protrude into the internal space 12 of the main body 10. In FIG. 1, the rod 52 is in the extended position, and in the retracted position, the state is as shown in FIG.

  The main body 10 is vertically displaceable in a substantially cylindrical casing (valve main body) 11 having a vertical axis arranged in the vertical direction and a cylindrical internal space 12 formed in the casing 11. The substantially disc-shaped valve body 21 provided and the substantially cylindrical spiral spring 31 that urges the valve body 11 upward (in other words, toward the drive unit 50) are provided.

  The valve body 21 is not connected to the rod 52 of the air cylinder 51, as is apparent from FIG. That is, the valve body 21 is separated from the rod 52. When the rod 52 is in the extended position, the valve body 21 is pressed against the valve seat 15 as shown in FIG. 1, but when the rod 52 is in the retracted position. Is displaceable in the vertical direction between the rod 52 and the valve seat 15.

  The upper end portion of the casing 11 (internal space 12) is open, and the air cylinder 51 of the drive unit 50 is attached thereto. For this reason, the rod 52 of the air cylinder 51 is located inside the internal space 12 of the casing 11. A flange 18 is formed at the lower end of the casing 11 so that the main body 10 (that is, the vent valve 1) can be connected to a vacuum chamber (or a pipe connected thereto) (not shown).

  The valve body 21 can be displaced in the vertical direction (in the direction of the central axis of the internal space 12) between a predetermined fully closed position and a predetermined fully open position in a cylindrical internal space 12 formed inside the casing 11. is there. A cylindrical inner surface (cylindrical side surface of the internal space 12) 11a of the casing 11 functions as a guide surface of the valve body 21 when the valve body 21 is displaced. Although the upper surface (front surface) of the valve body 21 is flat, a cylindrical recess 22 is formed at the center of the lower surface (rear surface), and an annular groove is formed outside the recess 22 so as to surround it. Is formed. An O-ring 23 is attached to the groove on the lower surface of the valve body 21. An upper end portion of a spring 31 is fitted into the concave portion 22, and a lower end of the spring 31 is supported by a spring support portion 32 on the bottom surface of the concave portion 22.

  A taper groove 13 having a substantially semicircular cross section is formed on the inner surface 11a of the casing 11. The number of taper grooves 13 is one. The tapered groove 13 is formed to provide an opening for allowing gas to flow between the inner surface 11a and the valve body 21. The depth of the taper groove 13 is zero at the lower end of the inner surface 11a (inner space 12) (horizontal plane on which the valve seat 15 is formed), and gradually increases toward the upper side (approaching the drive unit 50). Accordingly, the depth of the tapered groove 13 continuously increases monotonically from the lower end of the inner surface 11a (internal space 12) to the upper end thereof. This is because when the valve body 21 is in a position other than the closed position, an opening is formed between the casing 11 and the valve body 21, and the cross-sectional area of the opening is from the closed position of the valve body 21. This is to increase the displacement amount. The width and depth of the tapered groove 13 are determined so that an optimum gas flow rate can be obtained after the initial stage of gas introduction (that is, the middle stage and the last stage of introduction). It goes without saying that the shape and size of the tapered groove 13 can be arbitrarily changed as necessary.

  The valve body 21 is formed with a small through hole 24 extending along its central axis. The through hole 24 penetrates the valve body 21 in the displacement direction (vertical direction), and the space above the valve body 21 (inner space 12 in FIG. 1) and the lower space (in FIG. 1, the recess 22 and the gap 14). And the outlet passage 17) are interconnected. The size of the through hole 24 is determined so that an optimum gas flow rate can be obtained in the initial stage of introduction.

  The through hole 24 of the valve body 21 can be closed by a seal packing 53 fixed to the tip of the rod 52 of the air cylinder 51. That is, when the rod 52 is protruded and moved to the extended position, the valve body 21 is lowered against the elastic force of the spring 31, and the lower surface of the valve body 21 contacts the valve seat 15. Then, since the O-ring 23 of the valve body 21 is pressed against the valve seat 15, the communication between the internal space 12 (ie, the inlet passage 16) and the gap 14 (ie, the outlet passage 17) is blocked. At the same time, since the seal packing 53 is pressed against the upper surface of the valve body 21, the through hole 24 is closed by the seal packing 53. By sealing the through hole 24 in this way, the introduction (inflow) of gas into the vacuum chamber can be completely stopped. This operation is executed only by projecting the rod 52 of the air cylinder 51 and moving it to its extended position.

  Inside the casing 11, a cylindrical gap 14 having a smaller diameter is continuously formed at the lower end of the internal space 12. In other words, the side wall of the internal space 12 is narrowed inward at the lower end portion of the internal space 12, thereby forming a cylindrical gap 14 communicated with the lower end of the internal space 12. An annular valve seat 15 is formed at a portion where the side wall of the internal space 12 is narrowed so as to face the valve body 21. As shown in FIG. 1, the lower surface of the valve body 21 and the O-ring 23 are brought into contact with the valve seat 15, the vent valve is closed, and the introduction of gas is blocked. When the valve body 21 is separated from the valve seat 15, the vent valve is opened, and gas can be introduced.

  At the lower end portion of the gap 14, an annular spring support portion 32 and a substantially cylindrical outlet passage 17 are formed so that the side wall thereof is further narrowed inward and opposed to the valve body 21. The lower end of the spring 31 is supported by a spring support portion 32. The spring 31 is disposed in a substantially cylindrical space formed by the recess 22 and the gap 14 on the back surface of the valve body 21. The outlet passage 17 is for gas discharge.

  The outlet passage 17 is at a position overlapping the gap 14 at the lower end of the casing 11. The outlet passage 17 extends in the vertical direction on the longitudinal axis of the casing 11 and communicates with the gap 14, but is expanded inside the flange 18 according to the size of the flange 18.

  An inlet passage 16 for introducing gas is formed in the side wall near the upper end of the casing 11. The inlet passage 16 is substantially cylindrical and penetrates the side wall of the casing 11 in the horizontal direction (the direction orthogonal to the displacement direction of the valve body 21) to reach the upper portion of the internal space 12. The outer peripheral surface of the inlet passage 16 is threaded so that the tip of a gas supply pipe can be screwed in and connected. When air (atmosphere) is used as the gas, the inlet passage 16 need only be opened to the atmosphere as it is.

(Operation of the first embodiment)
Next, the operation (use state) of the vent valve 1 according to the first embodiment of the present invention having the above configuration will be described.

  First, using the flange 18, for example, the vent valve 1 is connected to an appropriate position in a gas introduction path of a vacuum chamber (not shown). The inside of the vacuum chamber is in a predetermined vacuum state (a negative pressure state with reference to atmospheric pressure). As a result, the vent valve 1 is connected to the vacuum chamber via its outlet passage 17. On the other hand, the inlet passage 16 of the vent valve 1 is opened to the atmosphere as it is when the introduced gas is air. When the introduced gas is a gas other than air, such as nitrogen gas, the inlet passage 16 is connected to the tip of a pipe for supplying nitrogen gas or the like. Thus, a predetermined gas is introduced into the inlet passage 16 and the internal space 12 of the vent valve 1.

  When the use of the vent valve 1 connected to the vacuum chamber as described above is started, as shown in FIG. 1, the rod 52 of the air cylinder 51 is protruded and placed in the extended position, and the valve body 21 is moved. Set to the closed position. That is, compressed air having a predetermined pressure is supplied from the air supply / exhaust port 54 to the inside of the air cylinder 51, and the air remaining in the air cylinder 51 is discharged from the air supply / exhaust port 55, thereby protruding the rod 52 downward. Then, as shown in FIG. 1, the rod 52 is stopped at the extended position. At this time, the valve body 21 is pressed downward against the elastic force of the spring 31 by the rod 52, and the O-ring 23 of the valve body 21 is brought into pressure contact with the valve seat 15, so that the internal space 12 (inlet Communication between the passage 16) and the gap 14 (exit passage 17) is blocked. At the same time, the through hole 24 of the valve body 21 is closed by the seal packing 53 fixed to the tip of the rod 52. Therefore, in this state, the gas in the inlet passage 16 and the internal space 12 is not introduced into the vacuum chamber through the vent valve 1. The position of the valve body 21 shown in FIG. In the state of FIG. 1, gas (its pressure is equal to atmospheric pressure) exists in the inlet passage 16 and the internal space 12, but the vacuum chamber (outlet passage 17) is in a vacuum state, so A downward pressing force acts on the gas.

  Next, compressed air having a predetermined pressure is supplied from the air supply / exhaust port 55 to the inside of the air cylinder 51, and the air remaining in the air cylinder 51 is discharged from the air supply / exhaust port 54, thereby moving the rod 52 upward. When retracted, the rod 52 stops at the retracted position as shown in FIG. As can be seen from FIG. 3, the vicinity of the tip of the rod 52 (including the seal packing 53) still protrudes into the internal space 12 even at the retracted position. At this time, the pressing force of the valve body 21 by the rod 52 disappears, but the state of the valve body 21 does not change and is held in the closed position. This is because the pressing force acting downward on the valve body 21 by the gas existing in the inlet passage 16 and the internal space 12 is larger than the elastic force acting upward on the valve body 21 by the spring 31. This is because the size of the spring and the elastic force of the spring 31 are adjusted. On the other hand, the minute through hole 24 formed in the valve body 21 is opened. This is because the seal packing 53 at the tip of the rod 52 moves away from the valve body 21 as the rod 52 is retracted.

  In the state of FIG. 3, the valve body 21 is held in its closed position, but since the minute through hole 24 formed in the valve body 21 is opened, the gas in the internal space 12 passes through the through hole 24. Through the air gap 14 and the outlet passage 17 into the vacuum chamber. At this time, that is, the gas flow rate at the initial stage of introduction is determined by the cross-sectional area of the through-hole 24. ) Is set within the range where the position does not deviate.

  At the initial stage of introduction, the pressure in the vacuum chamber slowly rises due to the gas flowing into the vacuum chamber through the through hole 24, and accordingly, the gas present on the outlet passage 17 side pushes up the valve body 21. The power increases gradually. In other words, the force that pushes down the valve body 21 gradually decreases. When the sum of the pushing force of the valve element 21 by the gas on the outlet passage 17 side and the pushing force of the valve element 21 by the spring 31 becomes larger than the pushing force of the valve element 21 by the gas on the inlet passage 16 side. The valve element 21 is pushed up and removed from the closed position, and is floated in the internal space 12 as shown in FIG. Thus, when the valve body 21 comes out of the closed position and floats, the initial stage of introduction is completed and the middle stage of introduction is entered.

  In the state of FIG. 4, the valve body 21 is not in contact with the seal packing 53 of the rod 52. The position at which the valve body 21 stops in this state is that the sum of the pushing force of the valve body 21 by the gas on the outlet passage 17 side and the pushing force of the valve body 21 by the spring 31 is due to the gas on the inlet passage 16 side. This position is equal to (equilibriums with) the pushing force of the valve body 21.

  Moreover, in the state of FIG. 4, the through hole 24 of the valve body 21 remains open. Further, since the valve body 21 is displaced upward and deviated from the closed position, that is, the valve body 21 is located at a position other than the closed position, the inner surface 11a of the casing 11 is vertically moved along the vertical axis thereof. The formed tapered groove 13 forms an opening between the inner surface 11a and the valve body 21. For this reason, the gas on the inlet passage 16 side passes through not only the through hole 24 of the valve body 21 but also this opening (that is, the tapered groove 13) and reaches the gap 14, and passes through the outlet passage 17 to reach the vacuum chamber. Flows in. Further, since the width and depth of the taper groove 13 monotonously increase as the distance from the lower end of the inner surface 11a increases, immediately before the valve element 21 comes out of its closed position and immediately reaches its fully open position. In other words, in the middle stage of gas introduction, the cross-sectional area of the opening (that is, the taper groove 13) between the inner surface 11a of the casing 11 and the valve body 21 corresponds to an increase in the displacement amount of the valve body 21 from the closed position. Monotonically increasing. As a result, as soon as the valve body 21 is removed from its closed position and the initial stage of introduction is completed, the total gas flow rate increases by an amount corresponding to the cross-sectional area of the opening, and thereafter the displacement of the valve body 21 increases. In response, it is gradually increased gradually. Thus, in the middle period of introduction, gas starts to be introduced into the vacuum chamber at a flow rate increased from the beginning of the introduction immediately after the end of the introduction period, thereby preventing a decrease in throughput.

  The total gas flow rate in the middle of the introduction is determined by the sum of the cross-sectional area of the through-hole 24 and the cross-sectional area of the opening (taper groove 13), and is considerably larger than that in the initial stage of introduction. Specifically, the total gas flow rate during the introduction period is generally set to the maximum value that can bring the inside of the vacuum chamber to atmospheric pressure in the shortest possible time within a range where no problems occur. It is.

  When the pressure in the vacuum chamber further rises, the pressure in the outlet passage 17 rises accordingly, and the pressure difference between the inlet passage 16 and the outlet passage 17 becomes small, so the influence of the elastic force of the spring 31 is large. Accordingly, the displacement amount of the valve body 21 further increases. Thus, the valve body 21 approaches its fully open position. During this time, the cross-sectional area of the opening (tapered groove 13) generated between the inner surface 11a of the casing 11 and the valve body 21 increases as the displacement amount of the valve body 21 increases. If the cross-sectional area of the opening is fixed (unchangeable) during this period, the gas flow rate is significantly reduced due to the reduction in the pressure difference between the inlet passage 16 and the outlet passage 17, and the time until the atmospheric pressure state is reached. Long and easy to reduce throughput. On the other hand, in the vent valve 1, the sectional area of the opening increases with an increase in the amount of displacement of the valve body 21, so that the gas flow rate decreases due to a decrease in the pressure difference between the inlet passage 16 and the outlet passage 17. As a result, a decrease in throughput is prevented or alleviated. During this period (that is, between the beginning of introduction and the end of introduction), the total gas flow rate and its change are the difference between the pressure difference between the inlet passage 16 and the outlet passage 17, the sectional area of the opening, and the sectional area of the through hole 24. Since it is determined by the relationship between the three, it is only necessary to appropriately set those values as necessary so that a desired total flow rate can be obtained.

  When the pressure in the vacuum chamber further increases and reaches the vicinity of atmospheric pressure, that is, at the end of introduction, the pressure difference between the inlet passage 16 and the outlet passage 17 is almost eliminated. For this reason, finally, the valve body 21 comes into contact with the seal packing 53 at the tip of the rod 52 in the retracted position and stops, as shown in FIG. This position is the fully open position of the valve body 21, and the sectional area of the opening is maximized.

  In the fully open position, the through hole 24 of the valve body 21 is closed by the seal packing 53, so that the gas on the inlet passage 16 side passes only through the opening (taper groove 13), passes through the outlet passage 17, and passes through the vacuum chamber. Flows in. Therefore, theoretically, at the end of introduction, the total flow rate of the gas is smaller than that immediately before, but the cross-sectional area of the through hole 24 is much smaller than the cross-sectional area of the opening, and the inlet passage 16 and the outlet Since the pressure difference with the passage 17 is also small, the influence of the closing of the through hole 24 on the gas flow rate is very small. Therefore, it can be considered that the gas flow rate at this time is determined by the pressure difference between the inlet passage 16 and the outlet passage 17 and the sectional area of the opening.

  Therefore, the elastic force or free length of the spring 31 is adjusted so that the valve body 21 does not contact the seal packing 53 even in the fully opened position, or the valve body 21 does not contact even if it contacts the seal packing 53. Thus, the through hole 24 may remain open even in the fully opened position. Even in this case, the seal packing 53 acts as a cushion to alleviate the impact of the valve body 21 when reaching the fully open position.

  As described above, when the pressure in the vacuum chamber becomes substantially the same value as the atmospheric pressure (that is, when the pressure returns to the atmospheric pressure state), the air cylinder 51 is operated to project the rod 52, and the valve body 21 is moved by the rod 52. Push down to return to the initial state of FIG. Then, the introduction of gas is interrupted, so that the operation of introducing gas into the vacuum chamber is completed.

  When the gas introduction operation into the vacuum chamber is performed again, the above-described operation may be repeated from the initial state of FIG.

  As described above, according to the vent valve 1 according to the first embodiment of the present invention, the valve body 21 is disposed in the closed position against the elastic force of the spring 31 by the air cylinder 51, When the through hole 24 is closed by the air cylinder 51, the communication between the inlet passage 16 and the outlet passage 17 is blocked. Therefore, in this state, even if gas is introduced into the internal space 12 from the inlet passage 16, the gas does not reach the outlet passage 17. That is, no gas is introduced into the vacuum chamber connected to the outlet passage 17.

  When the valve body 21 is in its closed position and the air cylinder 51 is operated to open the through hole 24 of the valve body 21, the inlet passage 16 and the outlet passage 17 communicate with each other through the through hole 24. The gas introduced into the internal space 12 from 16 can reach the outlet passage 17 at a flow rate corresponding to the cross-sectional area of the through hole 24. At this time, since the inside of the vacuum chamber connected to the outlet passage 17 is in a vacuum state, the valve body 21 moves toward the closed position by the pressure of the gas introduced into the internal space 12 (which is equal to the atmospheric pressure). The valve body 21 is pressed against the elastic force of the spring 31 and is held in the closed position by the pressing force. Therefore, by adjusting the cross-sectional area of the through-hole 24 to an appropriate value, the introduction of gas at a low flow rate and low flow rate required at the beginning of introduction is realized, and the rolling-up of particles in the vacuum chamber is reduced or prevented. can do.

  When nitrogen gas begins to be introduced into the vacuum chamber in this way, the pressure in the vacuum chamber gradually rises as the gas is introduced, so that the pressure in the outlet passage 17 also rises, and the pressing force acting on the valve body 21 (this) Is gradually increasing). When the sum of the pressing force due to the gas in the outlet passage 17 and the elastic force of the spring 31 becomes larger than the pressing force due to the gas in the inlet passage 16, the valve body 21 is disengaged from its closed position and begins to move toward its fully open position. . The amount of displacement of the valve body 21 at this time is such that the sum of the pressing force due to the gas in the outlet passage 17 and the elastic force of the spring 31 is equal to the pressing force due to the gas in the inlet passage 16, while It increases as the amount of gas introduced increases.

  While the valve body 21 is out of its closed position, that is, while the valve body 21 is in a position other than the closed position, the inlet passage 16 and the outlet passage 17 communicate with each other through the through hole 24 of the valve body 21. At the same time, the opening is generated by the tapered groove 13 between the inner surface 11 a of the casing 11 and the valve body 21. Therefore, the gas in the inlet passage 16 flows to the outlet passage 17 through the through hole 24 and the opening (tapered groove 13), that is, the total gas flow rate is in the opening (tapered groove 13). It increases by the amount corresponding to the cross-sectional area. Here, since the cross-sectional area of the opening (taper groove 13) increases in accordance with an increase in the amount of displacement from the closed position of the valve body 21, the total gas flow rate increases when the amount of displacement of the valve body 21 increases. It will increase with it. As a result, as soon as the valve body 21 is removed from the closed position (after the initial stage of introduction), the total gas flow rate increases by an amount corresponding to the cross-sectional area of the opening, and thereafter the displacement of the valve body 21 increases. It is automatically increased gradually according to the situation. Thus, immediately after the end of the introduction, gas starts to be introduced into the vacuum chamber at a flow rate increased from the beginning of the introduction, thereby preventing a decrease in throughput.

  When the pressure in the vacuum chamber further rises, the pressure in the outlet passage 17 rises accordingly, and the pressure difference between the inlet passage 16 and the outlet passage 17 decreases, so the influence of the elastic force of the spring 31 is large. Accordingly, the displacement amount of the valve body 21 further increases. Thus, the valve body 21 approaches its fully open position. During this time, the cross-sectional area of the opening (tapered groove 13) generated between the inner surface 11a of the casing 11 and the valve body 21 increases as the displacement amount of the valve body 21 increases. If the cross-sectional area of the opening is fixed (unchangeable) during this period, the gas flow rate is significantly reduced due to the reduction in the pressure difference between the inlet passage 16 and the outlet passage 17, and the time until the atmospheric pressure state is reached. Long and easy to reduce throughput. On the other hand, in the vent valve 1, the sectional area of the opening increases with an increase in the amount of displacement of the valve body 21, so that the gas flow rate decreases due to a decrease in the pressure difference between the inlet passage 16 and the outlet passage 17. As a result, a decrease in throughput is prevented or alleviated. During this period (that is, between the beginning of introduction and the end of introduction), the total gas flow rate and its change are the difference between the pressure difference between the inlet passage 16 and the outlet passage 17, the sectional area of the opening, and the sectional area of the through hole 24. Since it is determined by the relationship between the three, it is only necessary to appropriately set those values as necessary so that a desired total flow rate can be obtained.

  At the end of the introduction, there is almost no pressure difference between the inlet passage 16 and the outlet passage 17, and the valve element 21 reaches its fully open position by the elastic force of the spring 31. At this time, the cross-sectional area of the opening (tapered groove 13) is maximized. At the end of the introduction, the through-hole 24 may be closed or may remain open, but the cross-sectional area of the through-hole 24 is considerably smaller than the cross-sectional area of the opening. The effect on gas flow rate is small. Therefore, it can be said that the gas flow rate at this time is determined by the pressure difference between the inlet passage 16 and the outlet passage 17 and the sectional area of the opening.

  For the reasons described above, according to the vent valve 1 of the first embodiment of the present invention, when the gas is introduced into the vacuum chamber and the state in the vacuum chamber is returned from the vacuum (negative pressure) state to the atmospheric pressure state. By controlling the flow rate of the gas, it is possible to prevent both the particles from being rolled up and the throughput from being lowered in the vacuum chamber.

  Further, the vent valve 1 has a valve body 21 disposed in the internal space 12 of the casing 11 so as to be displaceable between a closed position and a fully opened position, and the valve body 21 is brought to its fully opened position by the elastic force of a spring 31. The vent valve 1 is configured in a simple manner because the valve body 21 is displaced toward the closed position by the air cylinder 51. In addition, any of these components does not require special properties and functions, and does not require special processing, so that the manufacturing cost of the vent valve 1 can be reduced.

  Further, the valve body 21 is displaced using the air cylinder 51 and the through-hole 24 is opened and closed, so that the gas is introduced into the vacuum chamber through the through-hole 24 at the initial stage of introduction and the total gas flow rate is kept small. ing. Immediately after the initial stage of introduction, the valve body 21 is displaced using the pressure difference between the inlet passage 16 and the outlet passage 17, thereby generating the opening between the inner surface 11a of the casing 11 and the valve body 21. The total gas flow rate is increased by an amount corresponding to the cross-sectional area of the opening. In addition, during the period from the beginning of introduction to the end of introduction, the inlet passage 16 and the outlet passage 17 are configured such that the cross-sectional area of the opening increases in accordance with an increase in the displacement amount of the valve body 21 due to the pressure difference. The reduction of the gas flow rate due to the reduction of the pressure difference with the gas is alleviated. Thus, if only the displacement of the valve body 21 using the air cylinder 51 and the opening and closing of the through hole 24 are performed at the initial stage of introduction, all other operations are automatically performed, and therefore the operation of the vent valve 1 is simple. .

  Therefore, the vent valve 1 according to the first embodiment of the present invention controls the gas flow rate when the gas is introduced into the vacuum chamber and the state inside the vacuum chamber is returned from the vacuum (negative pressure) state to the atmospheric pressure state. Thus, it is possible to realize both the prevention of particle rolling-up and the reduction of the throughput in the vacuum chamber, and the operation and configuration are simple and the manufacturing cost is low.

(Second Embodiment)
6 and 7 show the configuration of a vent valve 1A according to the second embodiment of the present invention. The vent valve 1A corresponds to the vent valve according to the second aspect of the present invention.

  As shown in FIGS. 6 and 7, the vent valve 1 </ b> A of the second embodiment replaces the taper groove 13 formed in the inner surface 11 a of the casing 11 with the casing 11 </ b> A in the horizontal direction (the direction in which the valve body 21 is displaced). Except that a plurality (six in this case) of through-holes 19 are formed in the vertical direction (the direction in which the valve body 21 is displaced) while penetrating in the direction orthogonal to each other. This is the same as the vent valve 1 of the first embodiment. These through holes 19 have the same size and the same shape. These six through-holes 19 constitute an opening that penetrates the casing 11A and communicates with the outside (atmosphere).

  Therefore, about the part with the same structure, the same code | symbol as used in the vent valve 1 of 1st Embodiment is attached | subjected, and the description is abbreviate | omitted. In addition, since the taper groove 13 does not exist, the inner surface 11Aa of the casing 11A is entirely cylindrical.

  In the vent valve 1A according to the second embodiment of the present invention, the casing 11A is formed with a plurality of through holes 19 penetrating in the horizontal direction and arranged at intervals along the vertical direction. When the valve body 21 is displaced upward from the closed position toward the fully open position, the valve body 21 is exposed to the internal space 12 step by step from the lowest through hole 19 according to the amount of displacement of the valve body 21, and as a result, Communication between the internal space 12 and the outside of the casing 11A is realized in stages.

  That is, immediately after the valve body 21 is pushed up and removed from the closed position, only the lowest through hole 19 is positioned (exposed) below the valve body 11, so that the internal space 12 of the casing 11 is at the lowest position. It communicates with the outside of the casing 11A (vent valve 1A) only through the through hole 19. Then, gas, that is, air (atmosphere) can be introduced from the outside into the internal space 12 through the through holes 19 opened to the atmosphere. For this reason, gas (air) is introduced into the internal space 12 through not only the through hole 24 of the valve body 21 but also the through hole 19 thereof, and further introduced into the vacuum chamber via the outlet passage 17. . As a result, the total flow rate of gas (air) increases by the amount corresponding to the cross-sectional area of the through hole 19.

  When the valve body 21 is further pushed up, the internal space 12 communicates with the outside of the casing 11A (the vent valve 1A) through the lowest through hole 19 and the second through hole 19 from the lowest. Then, gas (air) can be introduced into the internal space 12 not only through the through hole 24 of the valve body 21 but also through the two through holes 19 opened in the atmosphere. For this reason, the total flow rate of gas (air) increases by the amount corresponding to the sum of the cross-sectional areas of the two through holes 19.

  Thereafter, in the same manner, as the displacement amount of the valve body 21 increases, the number of the through holes 19 communicating with the internal space 12 increases, so that the flow rate of gas (air) corresponding to the cross-sectional area of each through hole 19 is increased. It will increase. And in the fully open position (refer FIG. 5) of the valve body 21, since all the six through-holes 19 are located under the valve body 11, not only the through-hole 24 of the valve body 21 but six through-holes. Gas (air) can be introduced into the internal space 12 through 19. For this reason, the total flow rate of gas (air) increases by the amount corresponding to the sum of the cross-sectional areas of the six through holes 19. At this time, the cross-sectional area of the opening that penetrates the casing 11A and communicates with the outside (atmosphere) is maximized.

  The vent valve 1A according to the second embodiment of the present invention penetrates through the casing 11A instead of the opening (the tapered groove 13 of the inner surface 11a of the casing 11) generated between the inner surface of the casing 11 and the valve body 21. The vent valve 1 of the first embodiment has the same configuration and operation as the vent valve 1 of the first embodiment except that a plurality of through holes 19 are provided as openings that communicate with the outside (atmosphere). It is clear that the same effect as the valve 1 can be obtained.

  Further, instead of the tapered groove 13 on the inner surface 11a of the casing 11, a plurality of through holes 19 that penetrate the casing 11A and communicate with the outside (atmosphere) are provided as the opening, so that the valve element 21 is displaced. A change in the cross-sectional area of the opening becomes stepwise. However, since it is only necessary to form a plurality of through-holes 19 that penetrate the casing 11A in a horizontal direction (a direction perpendicular to the displacement direction of the valve body 21) at a predetermined position, the opening is formed and processed in the first embodiment. There is an advantage that it is easier than the form.

  Note that the vent valve 1A of the second embodiment is provided with a plurality of through holes 19 as openings that penetrate the casing 11A and communicate with the outside (atmosphere), so that the gas introduced into the vacuum chamber is air ( Air) is preferred. However, if the same gas as the gas introduced into the internal space 12 from the inlet passage 16 can be introduced also from the through hole 19, a gas other than air can be used.

(Third embodiment)
FIG. 8 shows the configuration of the main body 10B of the vent valve according to the third embodiment of the present invention. This vent valve corresponds to the vent valve according to the first aspect of the present invention.

  As shown in FIG. 8, the vent valve according to the third embodiment is obtained by adding a taper groove 13a to the inner surface 11a of the casing 11 in the vent valve 1 according to the first embodiment described above, so that the total number of taper grooves is two. It is. Therefore, about the part with the same structure, the same code | symbol as used in the vent valve 1 of 1st Embodiment is attached | subjected, and the description is abbreviate | omitted.

  The shape and size of the taper groove 13a are the same except that the taper groove 13a is arranged at a position symmetrical to the position of the taper groove 13 with respect to the longitudinal axis (center axis) of the casing 11, and both have the same width and the same depth. And the same taper angle.

  As described above, the number of tapered grooves formed on the inner surface 11a of the casing 11 can be two, but is not limited thereto, and may be any number of three or more. The shape and size of the tapered groove may be different from each other. Arrangement of each taper groove is also arbitrary.

(Fourth embodiment)
FIG. 9 shows a configuration of a main body portion 10C of the vent valve according to the fourth embodiment of the present invention. This vent valve corresponds to the vent valve according to the second aspect of the present invention.

  As shown in FIG. 9, the vent valve of the fourth embodiment is spaced from the vent valve 1 </ b> A of the second embodiment described above along the direction in which the valve body 21 is displaced while passing through the casing 11 (vertical direction). A plurality (six in this case) of through holes 19a arranged in an open manner are added. Therefore, about the part with the same structure, the same code | symbol as used in 1 A of vent valves of 2nd Embodiment is attached | subjected, and the description is abbreviate | omitted.

  The shape and size of the through hole 19a are the same except that the through hole 19a is arranged at a position symmetrical to the position of the through hole 19 with respect to the longitudinal axis (center axis) of the casing 11C.

  As described above, the number of locations where the through holes penetrating the inner surface 11Ca of the casing 11C can be set to two, but is not limited thereto, and may be any number of three or more. The shape and size of the through holes may be different from each other.

(Fifth embodiment)
10 and 11 show the configuration of a vent valve 1D according to the fifth embodiment of the present invention. The vent valve 1D corresponds to the vent valve according to the first aspect of the present invention.

  As shown in FIG. 10 and FIG. 11, the vent valve 1D of the fifth embodiment is such that the entire inner surface 11Da of the casing 11D is a tapered cylindrical surface, and the other points are the first embodiment described above. The same as the vent valve 1 of FIG. Therefore, about the part with the same structure, the same code | symbol as used in the vent valve 1 of 1st Embodiment is attached | subjected, and the description is abbreviate | omitted.

  Since the inner surface 11Da of the casing 11D gradually spreads at a constant taper angle from its lower end (location where the valve seat 15 is located) to its upper end (open end), the valve body 21 is in a position other than its fully closed position. Sometimes, an annular opening is formed between the casing 11 </ b> D and the valve body 21, and the cross-sectional area of the opening increases as the displacement amount of the valve body 21 from the fully closed position increases. The magnitude of the taper angle is determined so as to obtain an optimum gas flow rate at the middle stage and the last stage of introduction.

  Since the vent valve 1D of the fifth embodiment of the present invention has such a configuration, it is apparent that the same effect as the vent valve 1 of the first embodiment can be obtained.

  Further, the opening formed between the inner surface 11Da of the casing 11D and the valve body 21 when the valve body 21 is in a position other than the fully closed position is annular, and exists over the entire circumference of the valve body 21. Therefore, the amount of change in the cross-sectional area of the opening is larger than that of the vent valve 1 of the first embodiment. Therefore, there is an advantage that the gas flow rate in the introduction middle period can be made larger than that in the first embodiment.

(Modification)
The first to fifth embodiments described above show examples embodying the present invention. Accordingly, the present invention is not limited to these embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the vent valve is described as being mounted such that the air cylinder is positioned at the upper position with the casing directed in the vertical direction, but this facilitates the displacement of the valve body. This is because the elastic force of the spring 31 is set in consideration of the weight of the valve body 21 and the spring 31. Therefore, if the parameters such as the elastic force of the spring 31 are appropriately adjusted in consideration of such points, the mounting direction of the vent valve is arbitrary, and for example, the air cylinder may be mounted at a lower position. However, the air cylinder may be mounted so as to be positioned in the horizontal direction.

  Moreover, although air or nitrogen gas is used as the gas introduced into the vacuum chamber, the present invention is not limited to this, and other inert gas (such as argon) or gas other than inert gas may be used as necessary. Good.

  As an actuator, an air cylinder is simple and preferable, but a valve body that can be displaced between a closed position and a fully opened position can be moved to the closed position in the initial stage of introduction, and the valve body is free after the initial stage of introduction. Needless to say, other devices may be used as long as they can be displaced.

It is principal part sectional drawing which shows the structure of the vent valve which concerns on 1st Embodiment of this invention, The cross section is shown about the main-body part, and the external appearance is each shown about the drive part. It is an end view by the side of the drive part of the main-body part of the vent valve which concerns on 1st Embodiment of this invention. It is principal part sectional drawing similar to FIG. 1 which shows operation | movement of the vent valve which concerns on 1st Embodiment of this invention. FIG. 6 is a cross-sectional view similar to FIG. 1 showing the operation of the vent valve according to the first embodiment of the present invention, and is a continuation of FIG. 3. FIG. 5 is a cross-sectional view similar to FIG. 1 showing the operation of the vent valve according to the first embodiment of the present invention, and is a continuation of FIG. 4. It is principal part sectional drawing which shows the structure of the vent valve which concerns on 2nd Embodiment of this invention, The cross section is shown about the main-body part, and the external appearance is each shown about the drive part. It is an end elevation along the AA line of Drawing 6 of a main part of a vent valve concerning a 2nd embodiment of the present invention. It is an end view by the side of the drive part of the main-body part of the vent valve which concerns on 3rd Embodiment of this invention. It is an end view by the side of the drive part of the main-body part of the vent valve which concerns on 4th Embodiment of this invention. It is principal part sectional drawing which shows the structure of the vent valve which concerns on 5th Embodiment of this invention, The cross section is shown about the main-body part, and the external appearance is each shown about the drive part. It is an end view by the side of the drive part of the main-body part of the vent valve which concerns on 5th Embodiment of this invention. It is a piping structure figure which shows the conventional method for introduce | transducing gas into a vacuum chamber in a vacuum state via a vent valve, and making it an atmospheric pressure state.

Explanation of symbols

1, 1A, 1D Vent valve 10, 10A, 10B, 10C, 10D Main body 11, 11A, 11B, 11C, 11D Casing 11a, 11Aa, 11Ba, 11Ca, 11Da Casing inner surface 12 Internal space 13, 13a Tapered groove 14 Gap 15 Valve seat 16 Inlet passage 17 Outlet passage 18 Flange 19 Through hole 21 Valve body 22 Valve body recess 23 O-ring 24 Valve body through-hole 31 Spring 32 Spring support portion 50 Drive portion 51 Air cylinder 52 Rod 53 Seal packing 54, 55 Air supply / exhaust port

Claims (13)

A vent valve used to introduce gas into the vacuum chamber and return the pressure in the vacuum chamber from a vacuum state to an atmospheric pressure state;
A casing having an inlet passage and an outlet passage;
An internal space formed inside the casing for connecting the inlet passage and the outlet passage;
A valve body disposed in the internal space so as to be displaceable between a predetermined closed position and a predetermined fully open position;
Biasing means for biasing the valve body toward the fully open position by an elastic force;
An actuator for displacing the valve body toward the closed position against the elastic force of the biasing means,
The valve body has a through hole communicating with the inlet passage and the outlet passage in the internal space, and the through hole can be closed by the actuator.
When the valve body is in the closed position and the through hole is closed by the actuator, communication between the inlet passage and the outlet passage is blocked,
When the valve body is in the closed position and the through hole is not closed by the actuator, the inlet passage and the outlet passage communicate with each other through the through hole,
When the valve body is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole, and an opening is generated between the inner surface of the casing and the valve body,
The vent valve according to claim 1, wherein a cross-sectional area of the opening portion increases in accordance with an increase in a displacement amount of the valve body from the closed position.   At least one tapered groove is formed in the inner surface of the casing, and the opening formed between the inner surface of the casing and the valve body when the valve body is in a position other than the closed position. The vent valve according to claim 1, wherein the vent valve is formed by a gap generated between the inner surface of the casing and the valve body by the at least one tapered groove.   The entire inner surface of the casing is tapered, and the opening formed between the inner surface of the casing and the valve body when the valve body is in a position other than the closed position is the casing. The vent valve according to claim 1, wherein the vent valve is formed by a gap generated between the inner surface of the valve body and the valve body. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space to contact the valve body, whereby the valve body is Configured to displace toward the closed position;
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed in the closed position;
The valve body is configured to be displaceable between the closed position and the fully opened position independently of the drive member when the drive member is in a predetermined retracted position. Vent valve. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space to contact the valve body, whereby the valve body is Configured to displace toward the closed position;
The vent valve according to any one of claims 1 to 3, wherein the through hole of the valve body is closed by pressing a sealing material attached to the driving member against the through hole. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space along the direction in which the valve body is displaced, and contacts the valve body. By making contact, the valve body is configured to be displaced toward the closed position,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed to the closed position, and the through hole of the valve body is formed by a sealing material attached to the drive member. Closed,
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully open position independently of the drive member;
The vent valve according to any one of claims 1 to 3, wherein a position where the valve body abuts on the drive member when the drive member is in a predetermined retracted position is the fully open position.   The vent valve according to any one of claims 1 to 6, wherein the actuator is an air cylinder, and the driving member of the actuator is a rod of the air cylinder. A vent valve used to introduce gas into the vacuum chamber and return the pressure in the vacuum chamber from a vacuum state to an atmospheric pressure state;
A casing having an inlet passage and an outlet passage;
An internal space formed inside the casing for connecting the inlet passage and the outlet passage;
A valve body disposed in the internal space so as to be displaceable between a predetermined closed position and a predetermined fully open position;
Biasing means for biasing the valve body toward the fully open position by an elastic force;
An actuator for displacing the valve body toward the closed position against the elastic force of the biasing means,
The valve body has a through hole communicating with the inlet passage and the outlet passage in the internal space, and the through hole can be closed by the actuator.
When the valve body is in the closed position and the through hole is closed by the actuator, communication between the inlet passage and the outlet passage is blocked,
When the valve body is in the closed position and the through hole is not closed by the actuator, the inlet passage and the outlet passage communicate with each other through the through hole,
When the valve body is in a position other than the closed position, the inlet passage and the outlet passage communicate with each other through the through hole, and an opening that penetrates the casing and communicates with the outside is generated.
The vent valve according to claim 1, wherein a cross-sectional area of the opening portion increases in accordance with an increase in a displacement amount of the valve body from the closed position.   When the casing has a plurality of through holes penetrating through the casing and arranged at intervals along a direction in which the valve body is displaced, and the valve body is in a position other than the closed position. The vent valve according to claim 8, wherein the generated opening is formed by at least one of the plurality of through holes. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space to contact the valve body, whereby the valve body is Configured to displace toward the closed position;
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed in the closed position;
The vent valve according to claim 8 or 9, wherein when the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully open position independently of the drive member. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space to contact the valve body, whereby the valve body is Configured to displace toward the closed position;
The vent valve according to claim 8 or 9, wherein the through hole of the valve body is closed by pressing a sealing material attached to the driving member against the through hole. The actuator has a drive member configured to be able to protrude into the internal space, and the drive member protrudes into the internal space along the direction in which the valve body is displaced, and contacts the valve body. By making contact, the valve body is configured to be displaced toward the closed position,
When the drive member is in a predetermined extended position, the valve body is pressed by the drive member and fixed to the closed position, and the through hole of the valve body is formed by a sealing material attached to the drive member. Closed,
When the drive member is in a predetermined retracted position, the valve body is displaceable between the closed position and the fully open position independently of the drive member;
The vent valve according to claim 8 or 9, wherein a position where the valve body abuts on the drive member when the drive member is in a predetermined retracted position is the fully open position.   The vent valve according to any one of claims 8 to 12, wherein the actuator is an air cylinder, and the driving member of the actuator is a rod of an air cylinder.

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