JP2006283994A - Cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism capable of preventing blockage of ice in an appliance such as a flow regulating valve by the ice made from the water separated out from a refrigerant when the refrigerant of room temperature is cooled to a low temperature of 0°C or less by a heat exchanger, in a cooling system for cooling the fluorine refrigerant in the heat exchanger by circulating the refrigerant. <P>SOLUTION: In this cooling system wherein the fluorine refrigerant W stored in a low-temperature tank 4 is cooled by the heat exchanger 3 of a refrigerating machine 2, and the cooled refrigerant is returned to the low-temperature tank 4 through the flow regulating valve 6, a heater H is mounted for heating a valve seat 6f part of the flow regulating valve 6, and the heater H is mounted on an outer peripheral face of a casing 6a opposite to the valve seat 6f formed in a state of projecting to an inner peripheral side of the casing 6a, by being wound like a coil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooling system such as a chiller unit, and in particular, a room temperature refrigerant having a low surface tension of fluorine, such as Galden (trade name, hereinafter, the same), Fluorinert (trade name, the same, the same), or the like is used. The present invention relates to a cooling system in which ice such as a flow regulating valve is prevented from being clogged with ice due to ice deposited from the refrigerant when the temperature is lowered.

  Fluorine-based refrigerants with low surface tension, such as Galden and Fluorinert, are used in, for example, a coolant that controls the temperature of a prober used in an electrical test (functional test) of a semiconductor element. Most semiconductor devices such as IC are made on a silicon wafer, and a semiconductor device having one function is subjected to a final electrical test (functional test) before, after, or after being cut out from the silicon wafer. The characteristics are measured and the quality is judged. In this test, a device called a prober is used that moves the wafer and adjusts the temperature of heating and cooling. Inside the prober is a table (XYZ table) that can be moved precisely in the three-dimensional direction, and a chuck for holding the wafer to be tested is attached to this table. This prober can set the temperature of the wafer to be tested within a range of, for example, −70 ° C. to 200 ° C.

  Control of the set temperature of the prober is performed by heating the chuck with an electric heater and cooling the chuck with a coolant. An example of a conventional system for heating and cooling the chuck will be described with reference to the flowchart of the cooling system in FIG. In FIG. 3, C is a chiller unit and P is a prober. In FIG. 3, for convenience of explanation, the chiller unit C, the refrigerator 2, the prober P casing, etc. are indicated by two-dot chain lines, and the low temperature tank 4, the normal temperature tank 8, etc. are shown so that the inside of the tank can be seen. is there.

  The chiller unit C includes a refrigerator 2 having a heat exchanger 3 and a heat-insulating low-temperature tank 4 in which a refrigerant R having a small surface tension such as Galden or Fluorinert is stored as a coolant. A circulation pump 5 for circulating the refrigerant R, a flow rate adjusting valve 6 for controlling the flow rate of the low-temperature refrigerant cooled by the heat exchanger 3, and a temperature sensor 7 for detecting the temperature of the refrigerant R in the low-temperature tank 4 The cold tank 4 is provided with a normal temperature tank 8 for replenishing the refrigerant, and a replenishment pump 9 for replenishing the low temperature tank 4 with the refrigerant of the normal temperature tank 8. The low temperature tank 4 and the normal temperature tank 8 are collectively referred to as refrigerant tanks.

  The heat exchanger 3 is composed of a double pipe (not shown). The refrigerant of the refrigerator 2 flows through the inner pipe, and the flow path formed between the inner pipe and the outer pipe has a low temperature. The refrigerant from the tank 4 flows. The heat exchanger 3 composed of a double pipe may be one in which a cooling fin is provided between the inner pipe and the outer pipe, or may be one in which no cooling fin is provided. Moreover, the refrigerant from the refrigerator 2 may flow through the flow path formed between the inner pipe and the outer pipe into the inner pipe with the refrigerant from the low temperature tank 4.

  The low-temperature tank 4 and the room temperature tank 8 are configured to be sealed or almost sealed, and air release tubes 10 and 11 that are open to the atmosphere are provided at the top. When the liquid level of the low temperature tank 4 or the normal temperature tank 8 rises or falls and the pressure fluctuation occurs in the low temperature tank 4 or the normal temperature tank 8, the atmospheric release tubes 10 and 11 absorb the pressure fluctuation. It is like that. The low temperature tank 4 is provided with an overflow pipe 12 connected to the normal temperature tank 8. When the refrigerant R in the low temperature tank 4 is insufficient, the supply pump 9 is driven to supply the refrigerant in the room temperature tank 8 to the low temperature tank 4 through the supply hose 9a. 4a indicates the refrigerant liquid level of the low temperature tank 4, and 8a indicates the refrigerant liquid level of the room temperature tank 8.

  The circulation pump 5 is attached to the low temperature tank 4 such that the pump portion is located in the refrigerant R stored in the low temperature tank 4 and the drive portion is located outside the low temperature tank 4. A suction port (not shown) of the circulation pump 5 opens into the low temperature tank 4, and its discharge port 5 a is connected to the heat exchanger inlet 3 a by a refrigerant circulation hose 13 (outward pipe), and the refrigerant circulation hose. 13 is connected to a prober P, which will be described later, by a coolant supply hose 15 branched from 13.

  As shown in FIG. 6, the flow rate adjusting valve 6 has a drive portion 6 b in the upper portion of a stainless steel casing 6 a and a valve portion in the lower portion thereof. The valve section includes a refrigerant inlet 6c that opens to the bottom of the casing 6a, a refrigerant outlet 6d that opens above the refrigerant inlet 6c and opens to a side surface of the casing 6a, and a refrigerant flow path 6e that connects the refrigerant inlet 6c and the refrigerant outlet 6d. The valve seat 6f integrated with the casing 6a formed in the middle of the refrigerant flow path 6e and the lower part of the valve seat 6f are arranged so as to be separated from the valve seat 6f from below the valve seat 6f to open and close the refrigerant flow path 6e. The valve body 6g is made of resin. The valve body 6g is connected to the drive portion 6b by a valve rod 6h and is biased toward the valve seat 6f by a return spring 6i from below. Further, the valve body 6g is guided by a guide member 6j protruding from the bottom of the casing 6a. In addition, 6k of FIG. 6 is the heat insulating material provided in the casing 6a.

  The flow rate adjusting valve 6 configured as described above is attached to the low temperature tank 4 so that the drive unit 6 b is located outside the low temperature tank 4 and the valve unit is located inside the low temperature tank 4. The refrigerant inlet 6c of the flow rate adjusting valve 6 is located below the refrigerant liquid level 4a in the low temperature tank 4, and the refrigerant outlet 6d is located above the refrigerant liquid level 4a. The refrigerant inlet 6c of the flow rate adjusting valve 6 is connected to a refrigerant circulation hose 14 (return pipe) connected to the heat exchanger outlet 3b via a joint 14a. The refrigerant outlet 6 d of the flow rate adjusting valve 6 opens into the low temperature tank 4.

  The refrigerant circulation hoses 13 and 14 are made of a material such as SUS, and are piped into the housing 1 of the chiller unit so as to rise upward from the low temperature tank 4 and then extend almost horizontally and connect to the heat exchanger 3. Has been. In FIG. 3, 2a is a pipe joint provided on the outer wall of the refrigerator 2 for the refrigerant circulation hose 13, and 2b is a pipe joint similarly provided on the outer wall of the refrigerator 2 for the refrigerant circulation hose 14. It is. 4b is a pipe joint provided on the outer wall of the low-temperature tank 4 for the refrigerant circulation hose 13, and 4c is a pipe joint provided on the outer wall of the low-temperature tank 4 for the refrigerant circulation hose 14.

  The prober P is a table that can be precisely moved in a three-dimensional direction, that is, an XYZ table (not shown), a chuck 17 that is attached to the table and holds a wafer to be tested, and detects the temperature of the chuck 17. A temperature sensor 18 for heating, a heater 19 for heating the chuck 17, and a cooling unit 20 for cooling the chuck 17 with a coolant.

  The cooling unit 20 has a coolant inlet (not shown) connected to a chuck connection hose 21 (outward pipe), and a coolant outlet (not shown) connected to a chuck connection hose 22 (return rod). . Further, the chuck connection hose 21 is connected to a coolant supply hose 15 (outward pipe) connected to the discharge port 4 a of the coolant circulation pump via a joint 23, and the chuck connection hose 22 is cooled to communicate with the low temperature tank 4. The liquid supply hose 16 (return rod) is connected via a joint 23. The chuck connection hoses 21 and 22 are made of a flexible material such as Teflon (registered trademark) resin so as to follow the movement of the prober P table. The coolant supply hoses 15 and 16 are made of a material such as SUS. In FIG. 3, 4 d is a joint provided on the outer wall of the low temperature tank 4 for the coolant supply hose 16.

  In the system configured as described above, when the set temperature of the chuck 17, that is, the set temperature of the prober P is about 40 ° C. or more, for example, the temperature control of the chuck 17 is performed only by the heater 19. The temperature of the chuck 17 is controlled by the heater 19 and the cooling unit 20. When the temperature control is performed only by the heater 19, the temperature of the chuck 17 is detected by the temperature sensor 18 provided in the prober P, and the heater 19 is controlled so that the temperature of the chuck 17 becomes the set temperature.

  When the temperature control of the chuck 17 is performed by the heater 19 and the cooling unit 20, the refrigerator 2 and the circulation pump 5 are operated. The refrigerant R in the low-temperature tank 4 sucked by the circulation pump 5 is supplied to the heat exchanger 3 provided in the refrigerator 2 through the refrigerant circulation hose 13, and at the same time, the coolant supply hose 15 and the chuck connection hose 21. And supplied to the cooling unit 20 of the chuck 17 provided in the prober P. The refrigerant supplied from the low temperature tank 4 to the heat exchanger 3 is cooled by the heat exchanger 3 and then returned to the low temperature tank 4 through the refrigerant circulation hose 14 and the flow rate adjusting valve 6. On the other hand, the coolant supplied as the cooling liquid to the cooling unit 20 of the chuck 17 cools the chuck 17 and then returns to the low temperature tank 4 through the chuck connection hose 22 and the cooling liquid supply hose 16.

  At this time, the flow rate adjusting valve 6 opens and closes based on, for example, an open command issued every 5 seconds, and the drive unit 6b controls the valve against the bias of the return spring 6i by this open command. The valve body 6g is driven so that the body 6g moves away from the valve seat 6f and opens the refrigerant flow path 6e for a predetermined time. When the refrigerant flow path 6e is opened, the low-temperature refrigerant cooled by the heat exchanger 3 is supplied into the low-temperature tank 4 through the refrigerant outlet 6d. When the predetermined time has elapsed, the valve body 6g is no longer driven by the drive unit 6b, and as shown in FIG. 4, the valve body 6g returns by the urging force of the return spring 6i to close the refrigerant flow path 6e. . The flow rate adjustment valve 6 repeats such opening and closing, and the refrigerant cooled by the heat exchanger 3 is supplied to the low temperature tank 4 so that the temperature of the refrigerant R in the low temperature tank 4 becomes a temperature corresponding to the set temperature of the chuck 17. To supply. The time during which the valve body 6g is opened, that is, the time during which the valve body 6g is kept open corresponds to the set temperature of the prober P. The higher the set temperature of the prober P, the shorter the time. The temperature of the refrigerant R in the low temperature tank 4 is monitored by a temperature sensor 7.

  By supplying the coolant R in the low-temperature tank 4 whose temperature has been adjusted in this way to the chuck 17 as a coolant, the set temperature of the prober is maintained. At the same time, the temperature of the chuck 17 is detected by the temperature sensor 18, and when the detected temperature of the chuck 17 is lower than the set temperature, the heater 19 is operated so as to reach the set temperature.

There is the following Patent Document 1 as a prior art document related to the refrigerant circulation device, and the following Patent Documents 2 and 3 as prior art documents related to the semiconductor inspection device.
JP-A-2003-148852 Japanese Patent Laid-Open No. 2-147973 Japanese Patent Laid-Open No. 2-147974

  In the cooling system configured as described above, when the system is operated under the condition that the refrigerant temperature in the low temperature tank 4 is about room temperature, the refrigerant temperature in the low temperature tank 4 is abnormally lowered, and the set temperature of the chuck 17 The phenomenon that it becomes difficult to maintain. The inventors analyzed the cause, and as shown in FIG. 7, the ice K is clogged in the flow rate adjusting valve 6, and the clogging of the ice K hinders the closing operation of the flow rate adjusting valve 6. It was found that the low-temperature refrigerant cooled by the heat exchanger 3 flows into the low-temperature tank 4 without adjusting the flow rate, and the refrigerant R in the low-temperature tank 4 is overcooled.

  Further, when this phenomenon was analyzed, it was found that the clogging of the ice K into the flow rate adjusting valve 6 occurred as follows. For example, as shown in FIG. 5, when the cooling system is operated with the set temperature T0 of the prober P set to 30 ° C., a refrigerant of about 27 ° C. (= T2) is supplied to the chuck 17 as a cooling liquid. There is a need to. On the other hand, the refrigerant supplied from the low temperature tank 4 to the heat exchanger 3 is cooled to about −75 ° C. (= T3) by the heat exchanger 3 and passes through the refrigerant circulation hose 14 to about −70 ° C. (= T4). ) And returned to the low temperature tank 4. The flow rate adjusting valve 6 is supplied to the heat exchanger 3 so as to maintain the refrigerant temperature T1 in the low temperature tank 4 at about 23 ° C. in order to supply the prober P with the coolant at 27 ° C. (= T2). The refrigerant flow rate is adjusted.

  By the way, a fluorine-based refrigerant having a small surface tension such as Galden or Fluorinert has a property that it easily absorbs moisture from the air at room temperature. As described above, the refrigerant temperature in the low temperature tank 4 is about 23 °. When the temperature is maintained at about room temperature of C, moisture is absorbed from the humid air existing in the low temperature tank 4. When the room-temperature refrigerant that has absorbed moisture in the low-temperature tank 4 is cooled to a low temperature of 0 ° C. or less by the heat exchanger 3 as described above, water precipitates from the refrigerant, and this water is converted into the heat exchanger 3. Cooled to ice. This ice may flow through the refrigerant supply hose 14 together with the cooled low-temperature refrigerant and be carried to the flow rate adjustment valve 6. In particular, it was found that in the case of the heat exchanger 3 composed of a double pipe not provided with fins, the amount of ice carried to the flow rate regulating valve 6 is large.

  When the low-temperature refrigerant R1 containing ice is conveyed to the flow rate adjustment valve 6, as shown in FIG. 7, when the flow rate adjustment valve 6 is opened, ice K is caught between the valve seat 6f and the valve body 6g, and the valve The seat 6f and the valve body 6g may freeze, causing an abnormality in the flow rate adjustment valve 6 that prevents the valve body 6g from returning. When such an abnormality occurs, the low temperature refrigerant R1 containing about −70 ° C. (= T4) ice cooled by the heat exchanger 3 flows into the low temperature tank 4 as it is without adjusting the flow rate. As described above, the refrigerant temperature T1 falls below about 23 ° C., and the set temperature of the prober P cannot be controlled to 30 ° C.

  Further, when the low-temperature refrigerant R1 containing ice is conveyed to the flow regulating valve 6 and flows between the valve seat 6f and the valve body 6g, the valve seat 6f and the valve body 6g are directly frozen, and the valve body 6g becomes the valve seat 6f. It is conceivable that the flow regulating valve 6 may be abnormal in that the valve body 6g cannot be opened and closed while sitting. When such an abnormality occurs, the refrigerant cooled in the heat exchanger 3 is not supplied to the low temperature tank 4, and conversely, the refrigerant temperature T1 in the low temperature tank 4 rises more than about 23 ° C., and the prober P The set temperature cannot be controlled to 30 ° C.

  In addition, in order to eliminate the influence of moisture contained in the fluorinated refrigerant, there is a filter that absorbs moisture contained in the fluorinated refrigerant in the state of water, but in the case of a filter that absorbs water, the water is absorbed. Since it is difficult to regenerate the filter without water and the filter needs to be replaced, there is a problem that maintenance is not easy.

  An object of the present invention is to cool a room temperature refrigerant at a low temperature of 0 ° C. or less by a heat exchanger in a cooling system that circulates a fluorine-based refrigerant having a low surface tension, such as Galden or Fluorinert, and cools it with a heat exchanger. It is an object of the present invention to provide a cooling system capable of eliminating the ice clogging when water is deposited from the refrigerant and becomes ice. In particular, a cooling system that eliminates ice clogging of devices such as flow control valves, based on the new knowledge that ice attached to devices such as flow control valves can be removed by heating devices such as flow control valves Is to provide.

  Means for solving the problems of the present invention include a fluorine-based refrigerant stored in a refrigerant tank and having a low surface tension, as in claim 1 (hereinafter referred to as “claim 1”). In a cooling system that is cooled by a heat exchanger of a refrigerator and returns the cooled refrigerant to the refrigerant tank via a device such as a flow rate adjusting valve, the valve seat portion of the device such as the flow rate adjusting valve is heated. A heater is provided.

  According to the configuration of claim 1, when the system is operated so that the refrigerant at room temperature in the refrigerant tank is cooled to a low temperature of 0 ° C. or less by the heat exchanger, water is precipitated from the refrigerant in the heat exchanger and becomes ice. This ice is transported together with the cooled refrigerant to equipment such as a flow control valve, which may cause clogging of the equipment such as the flow control valve. The ice clogging and the like generated in the device such as the flow rate adjusting valve is eliminated by heating with the above.

  In order to solve the above-mentioned problem, as in claim 2, the cooling system of claim 1 may be configured such that the heater can be energized for a certain period of time at regular intervals.

  According to the configuration of the second aspect, when the system is operated so that the room temperature refrigerant in the refrigerant tank is cooled to a low temperature of 0 ° C. or less by the heat exchanger, the heater is set to be energized for a certain period of time at regular intervals. By doing so, the valve seat part of the device such as the flow control valve can be heated periodically, so even if ice clogging occurs in the device such as the flow control valve, the ice automatically Eliminate clogging.

  In order to solve the above problem, as in claim 3, in the cooling system of claim 1, a temperature sensor for detecting the temperature of the refrigerant in the refrigerant tank is provided, and based on the temperature detected by the temperature sensor. You may make it the structure which supplies with electricity to the said heater.

  According to the configuration of the third aspect, the temperature of the refrigerant in the refrigerant tank is monitored by the temperature sensor, and when the refrigerant temperature becomes an abnormal value, the heater is energized and the valve seat portion of the device such as the flow regulating valve is Heat to eliminate clogging of ice that occurs in devices such as flow control valves. The heater may be energized manually or may be automatically energized in conjunction with the refrigerant temperature detected by the temperature sensor.

  Furthermore, in order to solve the above-mentioned problem, as in claim 4, in the cooling system according to any one of claims 1 to 3, the valve seat portion includes a casing made of a metal material of a device such as the flow regulating valve. It is good to comprise so that it may form integrally and the said heater may be wound around the outer periphery of the casing facing the said valve seat part.

  According to the configuration of claim 4, since the casing and the valve seat part of the device such as the flow rate adjusting valve are integrally formed from a metal material, if the outer periphery of the casing is heated by the heater, the heat is transferred to the valve seat part. It can be easily transmitted and can eliminate clogging of ice that occurs in devices such as flow control valves. Therefore, the heater only needs to be wound around the outer periphery of the casing of a device such as a flow rate adjusting valve, so the configuration of the heater can be simplified and the heater can be easily attached.

  According to the present invention, the refrigerant that easily absorbs moisture stored in the refrigerant tank is supplied to the heat exchanger provided in the refrigerator to be cooled, and the cooled low-temperature refrigerant is supplied to the refrigerant via a device such as a flow rate adjustment valve. In the cooling system that returns to the tank, a heater that heats the valve seat portion of the device such as the flow rate adjusting valve is provided, so that the room temperature refrigerant in the refrigerant tank is cooled to a low temperature of 0 ° C. or less in the heat exchanger. Even if the ice generated when the system is operated freezes on the valve seats of equipment such as flow control valves and ice clogging occurs, the frozen ice can be immediately removed by heating the heater, and the cooling system It can prevent driving from becoming unstable.

  Hereinafter, a first embodiment of a cooling system of the present invention will be described with reference to FIGS. FIG. 1 is a flowchart of a cooling system in which a flow rate adjusting valve provided with a heater is arranged, and FIG. 2 is a schematic diagram of the flow rate adjusting valve provided with a heater. In FIG. 1, members denoted by the same reference numerals as those in FIG. 3 have the same configuration as the members shown in FIG. 3 unless otherwise specified. For the same configurations, the description of FIG. Detailed description thereof will be omitted.

  In FIG. 1, C is a chiller unit, and a refrigerator 2 having a heat exchanger 3 and a fluorine-based refrigerant R having a small surface tension, such as Galden and Fluorinert, are used as a cooling liquid in a housing 1 of the chiller unit. A closed or almost sealed heat insulating low temperature tank 4 that is stored, a circulation pump 5 that is attached to the low temperature tank 4 to circulate the refrigerant, and a low temperature that is attached to the low temperature tank 4 and cooled by the heat exchanger 3. A flow rate adjusting valve 6 for controlling the flow rate of the refrigerant, a temperature sensor 7 for detecting the temperature of the refrigerant in the low temperature tank 4, a sealed or nearly sealed room temperature tank 8 for supplying the refrigerant to the low temperature tank 4, and a room temperature tank 8 And a replenishment pump 9 for feeding the refrigerant to the low temperature tank 4 through a replenishment hose 9a. As will be described later, a heater H that heats the valve portion of the flow rate adjustment valve 6 is attached to the flow rate adjustment valve 6 that is a device such as a flow rate adjustment valve in order to eliminate ice clogging and the like that occur in the flow rate adjustment valve 6. Yes. Reference numeral 10 denotes an air release tube provided on the upper part of the low temperature tank 4, 11 denotes an air release tube provided on the upper part of the normal temperature tank 8, and 12 denotes an overflow pipe.

  A suction port (not shown) of the circulation pump 5 opens into the low-temperature tank 4, and its discharge port 5 a is connected to the heat exchanger inlet 3 a by a refrigerant circulation hose 13 (outward pipe), and the refrigerant circulation hose. 13 is connected to a prober P, which will be described later, by a coolant supply hose 15 (outward pipe) branched from 13.

  The prober P is attached to an XYZ table (not shown), a chuck 17 that holds a wafer to be tested, a temperature sensor 18 that detects the temperature of the chuck 17, and heats the chuck 17. A heater 19 and a cooling unit 20 that cools the chuck 17 with a coolant are provided. The cooling unit 20 has a coolant inlet (not shown) connected to a chuck connection hose 21 (outward pipe), and a coolant outlet (not shown) connected to a chuck connection hose 22 (return rod). . Further, the chuck connection hose 21 is connected to a coolant supply hose 15 (outward pipe) connected to the discharge port 4 a of the coolant circulation pump via a joint 23, and the chuck connection hose 22 is cooled to communicate with the low temperature tank 4. The liquid supply hose 16 (return rod) is connected via a joint 23. The chuck connection hoses 21 and 22 are made of a flexible material such as Teflon (registered trademark) resin so as to follow the movement of the prober P table.

  FIG. 2 shows an example of a flow rate adjusting valve equipped with a heater H for heating the valve seat portion. In FIG. 2, members having the same reference numerals as those in FIG. 4 have the same configuration as the members shown in FIG. 4 unless otherwise specified. For the same configurations, the description of FIG. Detailed description thereof will be omitted.

  The flow rate adjusting valve 6 has a drive part 6b in the upper part of the casing 6a and a valve part in the lower part. The valve section includes a refrigerant inlet 6c that opens to the bottom of the casing 6a, a refrigerant outlet 6d that opens above the refrigerant inlet 6c to the side of the casing 6a, and a refrigerant flow path 6e that connects the refrigerant inlet 6c and the refrigerant outlet 6d. A valve seat 6f formed in the middle of the refrigerant flow path 6e, and a valve body 6g that is disposed below the valve seat 6f and opens and closes the refrigerant flow path 6e by being separated from the valve seat 6f from below the valve seat 6f. Has been. The casing 6a and the valve seat 6f of the flow rate adjusting valve 6 are integrally formed from a metal material such as stainless steel, and the valve body 6g is formed from a resin material such as BEAREE (trade name). The valve body 6g is connected to the drive portion 6b by a valve rod 6h and is biased toward the valve seat 6f by a return spring 6i from below. Further, the valve body 6g is guided by a guide member 6j protruding from the bottom of the casing 6a. In addition, 6k of FIG. 6 is the heat insulating material provided in the casing 6a.

  The heater H that heats the valve seat 6f is composed of a linear heating member, and is wound around the outer periphery of the casing 6a facing the valve seat 6f that is formed to protrude from the inner periphery of the casing 6a in a coil shape. It is attached. The width of the heater H is slightly larger than the thickness of the valve seat 6f. Although the capacity | capacitance of the heater H is suitably selected for every cooling system, what can heat the valve seat 6f to about 20 degreeC in a short time is employ | adopted, for example.

  Energization of the heater H can be performed by an appropriate means. For example, it is possible to employ a means that energizes the heater H for a certain period of time at regular intervals. In this case, when the system is operated so that the refrigerant R at room temperature in the refrigerant tank 4 is cooled to a low temperature of 0 ° C. or less by the heat exchanger 3, this means is activated and the flow rate adjusting valve is regularly operated for a certain period of time. The 6 valve seat 6f portion is heated. The energization interval and time are tested for each cooling system, and an appropriate time is set.

  Further, the heater H may be energized based on the temperature detected by the temperature sensor 7 that detects the temperature of the refrigerant in the refrigerant tank 4. In this case, the temperature of the refrigerant R in the low temperature tank 4 is monitored by the temperature sensor 7, and when the refrigerant temperature detected by the temperature sensor 7 becomes an abnormal value, the heater H is energized to The seat 6f part is heated. The heater H may be energized manually or may be automatically energized in conjunction with the refrigerant temperature detected by the temperature sensor. The energization time is set for each cooling system, and an appropriate time is set.

  In the cooling system configured as described above, when the set temperature of the chuck 17 is, for example, about 40 ° C. or more, the temperature control of the chuck 17 is performed only by the heater 19, and when the temperature is lower than that, the cooling with the heater 19 is performed. The temperature of the chuck 17 is controlled by the unit 20. When the temperature control is performed only by the heater 19, the temperature of the chuck 17 is detected by the temperature sensor 18 provided in the prober P, and the heater 19 is controlled so that the temperature of the chuck 17 becomes the set temperature.

  When the temperature control of the chuck 17 is performed by the heater 19 and the cooling unit 20, the refrigerator 2 and the circulation pump 5 are operated. The refrigerant R in the low-temperature tank 4 sucked by the circulation pump 5 is supplied to the heat exchanger 3 provided in the refrigerator 2 through the refrigerant circulation hose 13, and at the same time, the coolant supply hose 15 and the chuck connection hose 21. To the cooling unit 20 of the chuck 17 provided on the prober P. The refrigerant supplied to the heat exchanger 3 is cooled by the heat exchanger 3 and then returned to the low temperature tank 4 through the refrigerant circulation hose 14 and the flow rate adjusting valve 6. On the other hand, the coolant supplied as the cooling liquid to the cooling unit 20 of the chuck 17 cools the chuck 17 and then returns to the low temperature tank 4 via the chuck connection hose 22 and the cooling liquid supply hose 16.

  At this time, as described above, the flow rate adjusting valve 6 is opened and closed based on, for example, an open command issued every 5 seconds, and the drive unit 6b attaches the return spring 6i by this open command. The valve body 6g is driven so that the valve body 6g moves away from the valve seat 6f against the force and opens the refrigerant flow path 6e for a predetermined time. When the predetermined time has elapsed, the valve body 6g is moved by the urging force of the return spring 6i. It returns and the refrigerant flow path 6e is closed. In the normal state shown in FIG. 4, the flow rate adjusting valve 6 repeats such opening and closing, so that the temperature of the refrigerant R in the low temperature tank 4 becomes a temperature corresponding to the set temperature of the chuck 17. The cooled refrigerant is supplied to the low temperature tank 4. The time during which the valve body 6g is opened, that is, the time during which the valve body 6g is kept open corresponds to the set temperature of the chuck 17, and the time becomes shorter as the set temperature of the chuck is higher. The temperature of the refrigerant R in the low temperature tank 4 is monitored by a temperature sensor 7.

  By the way, as shown in FIG. 1, the set temperature T0 of the prober P is set to 30 ° C., for example, and the cooling system is operated so as to maintain the temperature T1 of the refrigerant in the low temperature tank 4 at a room temperature of about 23 ° C. In this case, when the refrigerant that has absorbed moisture from the humid air in the low temperature tank 4 or the normal temperature tank 8 is cooled to −75 ° C. (= T3) by the heat exchanger 3, the water in the refrigerant is precipitated and ice is formed. appear. The ice flows together with the cooled refrigerant through the refrigerant supply hose 14 and is carried to the flow rate adjusting valve 6. As described above, ice clogging or the like occurs between the valve seat 6f of the flow rate adjusting valve 6 and the valve body 6g. It happens that the body does not open and close normally. However, according to this embodiment, when ice clogging or the like occurs in the flow rate adjusting valve 6, the heater H wound around the outer periphery of the casing 6a is energized. Since the casing 6a and the valve seat 6f are integrally formed of a metal material such as stainless steel, the heat from the heater H is easily transferred from the casing 6a to the valve seat 6f, and the valve seat 6f is heated to about 20 ° C. By this heating, the ice between the valve seat 6f and the valve body 6g is melted, and the flow regulating valve 6 can be normally opened and closed.

  In addition, the water melt | dissolved by the heating of the valve seat 6f is collect | recovered by the low temperature tank 4 with a refrigerant | coolant. Since the water collected in the refrigerant tank 4 is separated from the refrigerant and collected on the refrigerant, the water is not circulated together with the refrigerant even if the refrigerant is circulated. When the amount of accumulated water increases, the water is appropriately discharged from the refrigerant tank 4.

  According to this embodiment, when the system is operated so that the room temperature refrigerant in the refrigerant tank 4 is cooled to a low temperature of 0 ° C. or less by the heat exchanger 3, ice clogging or the like may occur in the flow rate adjusting valve 6. However, by heating the valve seat 6f of the flow rate adjusting valve 6 with the heater H, ice clogging or the like generated in the flow rate adjusting valve 6 can be eliminated, and the set temperature of the prober can be controlled to be constant. Further, since the heating by the heater H can be performed even during the operation of the cooling system, it is not necessary to interrupt the operation of the cooling system in order to eliminate the ice clogging of the flow rate adjusting valve 6.

  Further, if the heater H is energized for a certain period of time at regular intervals, the ice clogging of the flow rate adjusting valve 6 can be automatically eliminated, and labor can be saved. Furthermore, if the heater H is energized based on the temperature detected by the temperature sensor 7 that detects the temperature of the refrigerant in the refrigerant tank 4, the ice clogging of the flow rate adjusting valve 6 can be finely resolved. . In this case, if the current is supplied in conjunction with the refrigerant temperature detected by the temperature sensor 7, the ice clogging of the flow rate adjusting valve 6 can be resolved finely and automatically.

  Further, the casing 6a and the valve seat 6f of the flow rate adjusting valve 6 are integrally formed from a metal material such as stainless steel having good heat conduction, and the heater H can be wound around and attached to the outer periphery of the casing 6a. The configuration of the heater can be simplified, and the heater can be easily attached.

  The heater H is not limited to a linear heater member, and an appropriate heater member such as a plate heater member can be employed. Further, the position where the heater member is attached is not limited to the outer periphery of the casing 6a of the flow rate adjusting valve 6. For example, when the valve seat 6f is formed of a resin material, the heater member is embedded in the resin valve seat 6f. You may do it. Further, a heater may be provided on the valve body that constitutes the valve portion of the flow rate adjustment valve 6.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes are possible, and any of them can be included in the present invention. For example, the cooling system of the present invention is not limited to that used in a prober, but can be used for any purpose as long as it is necessary to cool a refrigerant at room temperature to 0 ° C. or less with a heat exchanger. May be. Further, the present invention is not limited to a cooling system provided with a flow rate adjusting valve, and can be widely applied to those provided with a device that causes an abnormality due to ice generated in a heat exchanger.

The flowchart of the cooling system which concerns on embodiment of this invention. Schematic of the flow regulating valve provided with the heater which concerns on embodiment of this invention. The flowchart of the conventional cooling system. Schematic which shows the normal state of a flow regulating valve. Schematic which shows the abnormal state of a flow regulating valve in the conventional cooling system.

Explanation of symbols

C Chiller unit P Prober H Heater 1 Chiller unit housing 2 Compressor 3 Heat exchanger 4 Low temperature tank 5 Circulation pump 6 Flow control valve 7 Temperature sensor 8 Normal temperature tank 10, 11 Air release tube 13, 14 Refrigerant circulation hose 15, 16 Cooling Liquid supply hose 17 Chuck 18 Temperature sensor 19 Heater 20 Cooling unit 21, 22 Chuck connection hose

Claims (4)

In a cooling system in which a fluorine-based refrigerant having a low surface tension stored in a refrigerant tank is cooled by a heat exchanger of a refrigerator, and the cooled refrigerant is returned to the refrigerant tank via a device such as a flow rate adjusting valve. A cooling system provided with a heater for heating a valve seat portion of the device such as the flow rate adjusting valve The cooling system according to claim 1, wherein the heater can be energized for a certain period of time at regular intervals. The cooling system which provided the temperature sensor which detects the temperature of the refrigerant | coolant in the said refrigerant | coolant tank, and energized the said heater based on the temperature which this temperature sensor detected. The said valve seat part is formed integrally with the casing which consists of metal materials of apparatus, such as this flow control valve, and the said heater was wound around the outer periphery of the casing facing the said valve seat part, and was provided. The cooling system according to any one of the above.

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