JP2008208965A - Check valve and pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a check valve functioning as a flow amount detector for detecting a flow amount approximate to zero while securing free distribution of water, and to provide a pump device equipped therewith. <P>SOLUTION: The check valve comprises a valve element 1 for abutting on a valve seat 10 provided in a liquid passage 11, a valve rod 2 to be moved integrally with the valve element 1, a guide member 3 having a hole into which the valve rod 2 is slidably inserted, a magnet 6 embedded in the valve rod 2, and a reed switch 7 to be opened/closed with the operation of a magnetic field. The reed switch 7 is arranged on the side of the magnet 6 against the moving direction of the valve rod 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a check valve having a function of a flow rate detector (flow switch) and a pump device including the check valve, and more particularly to a check valve suitably used for a water supply device.

  Water supply devices are widely used as facilities for supplying water to buildings such as houses. A water supply device generally includes a pump that draws water from a water source, a pressure detector that detects water pressure on the discharge side of the pump, a flow rate detector that detects the flow rate of water, and a check valve that prevents back flow of water to the water source. Etc. (see Patent Documents 1 and 2).

  When the customer uses water with the pump stopped (for example, when the faucet is opened), the water pressure on the discharge side of the pump gradually decreases. When the water pressure drops to a predetermined value, the pressure detector detects this and activates the pump. On the other hand, when the use of water at the customer is stopped (for example, when the faucet is closed), the flow rate of the water decreases, and the flow rate detector detects that the flow rate has decreased to a predetermined value and stops the pump. Let In this way, the pump is started based on the water pressure, and the pump is stopped based on the water flow rate.

  Patent Documents 1 and 2 describe a check valve having the function of a flow rate detector. A magnet is embedded in the check valve, and a reed switch that is opened and closed by the action of a magnetic field is disposed above the magnet. In this configuration, when the check valve moves downward and the magnet leaves the reed switch, the reed switch is turned off (opened). Since the vertical position of the check valve is generally proportional to the flow rate of water, the pump is stopped when the reed switch is turned off.

Japanese Examined Patent Publication No. 6-63502 Japanese Examined Patent Publication No. 6-63503

  In the water supply apparatus described above, it is ideal that the flow rate detector can detect that the flow rate of water has become zero. This is due to the following reason. The flow rate of the water supplied from the water supply device depends on the amount of water used at the demand destination. It is assumed that water is used at various flow rates at the customer, for example, there is a case where very little water is continuously used at the customer (that is, when the faucet is kept slightly open). obtain. However, in such a case, if the detected flow rate set in the flow detector is larger than the amount of water used at the customer, the pump will stop even though the customer uses water. End up. Once the pump is stopped, the water pressure drops, the pressure detector detects this and the pump is started again. At this time, since the flow rate remains low, the pump stops again. As a result, a so-called inching phenomenon occurs in which the pump is repeatedly started and stopped.

In the configuration described in the above-mentioned patent document, the position where the reed switch opens (position where the pump stops) is far away from the position where the check valve contacts the valve seat (position where the flow rate is 0). Is likely to occur. On the other hand, when the installation position of the reed switch is lowered, the vertical stroke of the check valve is inevitably shortened, which adversely affects the flow of water.
The present invention has been made in view of the above-described conventional problems, and includes a check valve having a function of a flow rate detector capable of detecting a flow rate close to 0 while ensuring a free flow of water. It aims at providing the pump apparatus provided with this check valve.

  In order to achieve the above-described object, according to one aspect of the present invention, a valve body that abuts a valve seat provided in a liquid passage, a valve rod that moves integrally with the valve body, and the valve rod slides. A guide member having a hole that can be inserted, a magnet embedded in the valve stem, and a reed switch that opens and closes by the action of a magnetic field, the reed switch with respect to the movement direction of the valve stem. The check valve is arranged on the side of the magnet.

In a preferred aspect of the present invention, the reed switch is arranged in parallel with the valve stem.
In a preferred aspect of the present invention, the magnet is always located inside the guide member.
In a preferred aspect of the present invention, a distance between the position of the valve body when the reed switch is opened and the position of the valve body in contact with the valve seat is 5 mm or less.
In a preferred aspect of the present invention, the valve stem and the guide member are arranged along a vertical direction.

  Another aspect of the present invention includes a pump disposed between the suction port and the discharge port, an electric motor that drives the pump, a pressure tank that holds a discharge side pressure of the pump, and the check valve, And a control device for controlling the operation of the pump.

In a preferred aspect of the present invention, the control device includes an inverter.
In a preferred aspect of the present invention, the check valve is disposed at a position higher than the impeller of the pump.
In a preferred aspect of the present invention, the guide member and the reed switch are attached to a case, and a screw thread is formed on the outer peripheral surface of the case, and screwed into a screw hole formed in the liquid passage having the valve seat. Thus, the case is mounted.

  According to the present invention, since the position of the valve body when the reed switch is opened can be brought close to the valve seat, a flow rate close to 0 can be detected. In addition, since the stroke of the valve body can be kept large, it is possible to ensure the liquid flow.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a check valve according to an embodiment of the present invention, and shows a state when the check valve is closed. FIG. 2 is a view of the valve body shown in FIG. 1 when viewed from the direction of arrow II. FIG. 3 is a sectional view showing a state when the check valve shown in FIG. 1 is opened.

  As shown in FIG. 1, the check valve is a valve body 1 that abuts a valve seat 10 provided in a conduit (liquid passage) 11, and is fixed to the valve body 1 and moves integrally with the valve body 1. A possible valve stem 2, a guide member 3 for guiding the movement of the valve stem 2 and the valve body 1, and a case 4 to which the guide member 3 is fixed are provided. In this embodiment, the valve seat 10 is formed integrally with the conduit 11, but the valve seat 10 may be provided as a separate member from the conduit 11.

  The valve body 1 basically includes a main body portion 1a, an annular seal member 1b, and a plurality of guide plates 1c extending downward from the lower surface of the main body portion 1a. As can be seen from FIG. 2, the cross section of the main body 1a is circular. The plurality of guide plates 1c have a radially extending shape when the valve body 1 is viewed from below, and are circular when the outer end surfaces of these guide plates 1c are connected by lines. As shown in FIG. 1, the seal member 1b is attached to the outer peripheral surface of the main body 1a, and the seal member 1b comes into contact with the valve seat 10 when the valve body 1 is lowered. The seal member 1b is formed from an elastic material such as rubber.

  The conduit 11 has an inverted L shape, and includes an inlet-side conduit 11a extending in the vertical direction, a valve chamber 11b in which the valve body 1 is accommodated, and an outlet-side conduit 11c extending laterally from the valve chamber 11b. It is composed of The inlet side conduit 11a, the valve chamber 11b, and the outlet side conduit 11c are integrally formed. The valve seat 10 has a cylindrical shape, and the upper end of the valve seat 10 constitutes a contact surface with the valve body 1. As shown by the arrow in FIG. 3, the liquid flows upward in the inlet side conduit 11a, flows into the valve chamber 11b through the valve seat 10, and flows out to the outlet side conduit 11c.

  A screw thread is carved on the lower outer peripheral surface of the case 4, and the case 4 is detachably attached to a screw hole formed in the upper part of the valve chamber 11b. Further, an O-ring 5 is provided in order to prevent liquid leakage from a minute gap between the case 4 and the valve chamber 11b. Most of the guide member 3 is embedded in the case 4, and only a part including the lower end of the guide member 3 protrudes from the lower surface of the case 4.

  The valve stem 2 has a columnar shape and is inserted into a cylindrical guide member 3. The inner diameter of the guide member 3 (the diameter of the hole into which the valve stem 2 is inserted) is slightly larger than the diameter of the valve stem 2, and the valve stem 2 can slide within the guide member 3. In the present embodiment, the guide member 3 is disposed along the vertical direction, and the valve body 1 and the valve stem 2 are movable in a direction approaching and separating from the valve seat 10 (that is, the vertical direction).

  As shown in FIG. 3, the valve body 1 and the valve stem 2 are lifted upward by the flow of liquid. The vertical position of the valve body 1 is generally proportional to the liquid flow rate. FIG. 3 shows a state in which the valve body 1 is in the fully open position, and the lower end of the valve body 1 (the lower end of the guide plate 1 c) at this position is located below the upper end of the valve seat 10. Therefore, the downward movement of the valve body 1 is not hindered by the valve seat 10, and a reliable closing operation of the valve body 1 is ensured. Further, since a relatively large gap is formed between the guide plates 1c, a free flow of liquid is ensured while guiding the movement of the valve body 1 by the guide plate 1c.

  When the flow of liquid disappears, the valve body 1 and the valve stem 2 move downward due to their own weight, and the valve body 1 comes into contact with the valve seat 10. Further, when a liquid flows from the outlet side conduit 11c toward the inlet side conduit 11a, the valve body 1 is quickly lowered by the flow of the liquid, and the valve body 1 is pressed against the valve seat 10 by the liquid. Accordingly, the backflow of the liquid from the outlet side conduit 11c toward the inlet side conduit 11a is prevented.

  A magnet 6 is provided near the upper end of the valve stem 2. The magnet 6 is completely embedded in the valve stem 2 so as not to come into contact with the liquid. Examples of the material constituting the magnet 6 include ferrite and neodymium. In general, when the magnetic force of the magnet is strong, the iron sand in the liquid is attracted, and the iron sand enters a minute gap between the guide member 3 and the valve stem 2. From such a viewpoint, it is preferable to use a ferrite magnet having a weak magnetic force as the magnet 6.

  As shown in FIG. 1, the magnet 6 is located above the lower end of the guide member 3 when the valve body 1 is in the fully closed position (lowermost position). That is, the magnet 6 is always located inside the guide member 3 regardless of the position of the valve body 1. By adopting such an arrangement, sand iron is not attracted to the magnet 6 and fixed to the outer peripheral surface of the valve stem 2, and free vertical movement of the valve stem 2 can be ensured.

  A reed switch 7 is disposed on the side of the guide member 3. The reed switch 7 is disposed inside the case 4 and is connected to a connector 14 via a lead wire 13. The reed switch 7 is arranged along the vertical direction, that is, parallel to the valve stem 2. As the reed switch 7, a known reed switch in which the contact points of the two lead pieces are opened and closed by the action of a magnetic field can be used. As shown in FIGS. 1 and 3, the magnet 6 and the reed switch 7 are arranged such that a contact (not shown) of the reed switch 7 is positioned between the uppermost position and the lowermost position of the magnet 6. The arrangement of the reed switch 7 is not limited to the vertical direction (parallel to the valve stem 2), and may be in the horizontal direction (direction orthogonal to the valve stem 2) as long as it is on the side of the magnet 6.

  When the valve body 1 is in the fully open position, the reed switch 7 is closed (ON state) by the action of the magnetic field of the magnet 6, and when the valve body 1 is in the fully closed position, the reed switch 7 is separated from the magnetic field of the magnet 6. Is open (OFF state). When this check valve is used in the water supply device, the operation of the pump is stopped when the reed switch 7 is opened. A water supply apparatus incorporating this check valve will be described later.

  In the present embodiment, the distance between the position of the valve body 1 when the reed switch 7 is released from the magnetic field of the magnet 6 and the reed switch 7 is opened and the position of the valve body 1 in contact with the valve seat 10 (hereinafter referred to as “reed switch 7”). , Which is referred to as a valve body movement distance) is set within a range of 2 to 5 mm. This is because, when the valve body moving distance is large, when the reed switch 7 is opened and the pump is stopped, the valve body 1 is pushed by the high-pressure liquid and vigorously contacts the valve seat 10 to generate a loud sound. Because. From such a viewpoint, it is preferable that the moving distance of the valve body is 5 mm or less, more preferably 3 mm or less, and most preferably 0 mm.

  FIG. 4 is a sectional view showing a check valve according to another embodiment of the present invention. The difference between this embodiment and the embodiment described above is that a pressing spring 15 that presses the valve body 1 against the valve seat 10 is provided. That is, as shown in FIG. 4, the pressing spring 15 is disposed between the lower surface of the case 4 and the upper surface of the valve body 1 and is gently attached to the valve stem 2. According to such a configuration, the valve body 1 is quickly closed by the pressing spring 15 at the same time as the flow of the liquid disappears, so that the so-called water hammer can be prevented from being generated.

  FIG. 5 is a schematic view showing a water supply apparatus incorporating the check valve of the present embodiment. As shown in FIG. 5, the water supply device 20 includes the check valve 21, the pump 23, the electric motor 24 that drives the pump 23, and the control unit 25 that controls the start and stop of the pump 23. . The check valve 21 is connected to a water source (for example, a well or a water receiving tank) 22 via a conduit 11, and the check valve 21 is connected to a pump 23 via a conduit 11. As described above, the check valve 21 not only prevents the backflow of water, but also functions as a flow switch (flow rate detector) that detects that the flow rate of the water flowing through the conduit 11 has decreased to a predetermined value. .

  A discharge pipe 26 is connected to the discharge port of the pump 23. The discharge pipe 26 includes a pressure detector (for example, a pressure sensor) 27 that detects that the water pressure in the discharge pipe 26 (pressure on the discharge side of the pump 23) has decreased to a predetermined value, and water in the discharge pipe 26. And a pressure tank 29 for storing in a pressurized state. The check valve 21, the pressure detector 27, and the electric motor 24 are connected to the control unit 25.

  The discharge pipe 26 is connected to a water supply pipe 30 extending to a water supply terminal 31 of a building such as a house, and the water of the water source 22 is supplied to the demand destination by the water supply apparatus 20. These water supply terminals 31 are, for example, a water tap (faucet), a water heater, or the like.

  When water is used at the water supply terminal 31, the water pressure in the discharge pipe 26 gradually decreases. When the water pressure reaches a predetermined value, the pressure detector 27 detects this, and the electric motor 24 is started by the command from the control unit 25, and the pump 23 is driven. When the pump 23 is driven by the electric motor 24, the water from the water source 22 is sucked into the pump 23 through the conduit 11 and discharged to the discharge pipe 26 at a predetermined pressure. The water discharged to the discharge pipe 26 is supplied to the water supply terminal 31 through the water supply pipe 30.

  When the amount of water used at the feed end 31 decreases during the operation of the pump 23 and the flow rate of the water flowing through the conduit 11 decreases to a predetermined value, the reed switch 7 (see FIG. 1) of the check valve 21 is turned off. Then, the control unit 25 stops the electric motor 24 and stops the pump 23. Thereafter, when water is used at the water supply end 31, water is supplied from the pressure tank 29 for a while, but when the water in the pressure tank 29 decreases and the water pressure in the discharge pipe 26 decreases to a predetermined value, The pump 23 is started again.

  In addition, although the water supply apparatus 20 mentioned above is a type which pumps up the water of a well or a receiving tank, the non-return valve of this invention can also be used for what is called a direct connection type water supply apparatus directly connected to the water main. Moreover, it can also be used for a water supply apparatus configured by connecting a plurality of pumps in parallel. In this case, the check valve is provided on the discharge side of each pump (in the example of FIG. 5, the pump 23 and the pressure detector 27). Between the two).

Next, the specific structural example at the time of applying the check valve which concerns on embodiment of this invention mentioned above to the water supply apparatus for shallow wells is demonstrated.
FIG. 6 is a plan view showing a shallow well water supply apparatus provided with a check valve according to an embodiment of the present invention, and FIG. 7 is a partial sectional front view of the water supply apparatus shown in FIG.

  A water supply device (pump device) 101 shown in FIGS. 6 and 7 includes a cascade pump 110 as a pump. The cascade pump is a pump also called a friction pump, and includes an impeller 111 formed as a disk having a large number of grooves formed on the periphery. Although this pump is small in size, a single impeller can obtain a lift comparable to several stages of centrifugal pumps, and is suitable for the purpose of a small capacity and high lift. Moreover, since it has a self-absorbing property, it is suitable for supplying water or well water stored in a water receiving tank to supply water to the home. The impeller 111 is accommodated in the pump casing 112. A pump casing cover 113 is attached with bolts to the front surface of the pump casing 112 as viewed from the axial direction of the impeller 111. When the pump casing cover 113 is removed, the impeller 111 can be accessed and maintenance inspection is easy.

  In addition, the water supply apparatus 101 includes an electric motor 120 that drives the pump 110. The pump 110 includes an inverter device 130 so that the discharge pressure can be controlled by performing variable speed operation. The inverter device 130 is disposed in the vicinity of the electric motor 120.

  The check valve 21 described above is disposed in the conduit 11 between the suction port 126 and the impeller 111. The case 4 that accommodates the reed switch 7 and the guide member 3 (see FIG. 1) is screwed into a screw hole formed in the conduit 11, and the O-ring 5 (see FIG. 1) makes a minute connection between the case 4 and the conduit 11. Gaps are sealed. In this way, the check valve 21 can be easily mounted simply by screwing the case 4.

  A steam / water separation chamber 121 is provided on the downstream side of the impeller 111, and a pressure detector (pressure sensor, pressure transmitter) 123 is disposed on the downstream side of the steam / water separation chamber 121. The pressure sensor 123 is disposed in a discharge pipe 125 provided downstream of the steam / water separation chamber 121. The operation of the pump 110 is controlled by the inverter device 130 so that the detected pressure of the pressure sensor 123 becomes a preset target pressure. A discharge port 127 is provided downstream of the discharge pipe 125. A pressure tank 122 is connected to the discharge pipe 125. An expelling tap 128 is provided in the upper part of the steam / water separation chamber 121. The pressure tank 122 is provided on the discharge side of the pump 110.

  From the viewpoint of maintaining the pressure on the discharge side, the check valve 21 is not limited to the position shown in FIGS. 6 and 7, and may be upstream of the position where the pressure tank 122 of the discharge pipe 125 is attached. However, it is preferable to provide on the suction side of the pump 110 from the viewpoint of holding the expiration water. In the example shown in FIGS. 6 and 7, the check valve 21 is located on the suction side of the pump 110 and is disposed at a position higher than the impeller 111. This is because even when the check valve 21 has leaked due to sand or the like, the amount of water necessary for expiration can be secured.

  The pump 110, the electric motor 120, the inverter device 130, and the pressure tank 122 are placed on the unit base 132 and fixed with bolts, and are compactly assembled as a whole. Also, a resin unit cover 131 is provided to cover the entire apparatus. The unit cover 131 is formed with openings 131a and 131b that allow the suction port 126 and the discharge port 127 of the pump 110 to be accessed from the outside. The unit cover 131 and the unit base 132 substantially seal the entire component device. Covering. Therefore, the components can be protected from wind and rain, and a high soundproofing effect is provided.

  Although the embodiments of the present invention have been described so far, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims, the specification, and the drawings. Deformation is possible.

It is sectional drawing which shows the non-return valve which concerns on one Embodiment of this invention, and shows a state when a non-return valve closes. It is a figure when the valve body shown in FIG. 1 is seen from the direction of arrow II. It is sectional drawing which shows a state when the non-return valve shown in FIG. 1 opens. It is sectional drawing which shows the non-return valve which concerns on other embodiment of this invention. It is a schematic diagram which shows the water supply apparatus incorporating the check valve of this embodiment. It is a top view which shows the water supply apparatus for shallow wells provided with the check valve which concerns on one Embodiment of this invention. It is a partial cross section front view of the water supply apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve body 1a Main-body part 1b Seal member 1c Guide plate 2 Valve rod 3 Guide member 4 Case 5 O-ring 6 Magnet 7 Reed switch 10 Valve seat 11 Conduit 11a Inlet side conduit 11b Valve chamber 11c Outlet side conduit 13 Lead wire 14 Connector 15 Pressure spring 20 Water supply device 21 Check valve 22 Water source 23 Pump 24 Electric motor 25 Control unit 26 Discharge pipe 27 Pressure detector 29 Pressure tank 30 Water supply pipe 31 Water supply terminal 101 Water supply device 110 Pump 111 Impeller 112 Pump casing 113 Pump casing cover 120 Electric motor 121 Air / water separation chamber 122 Pressure tank 123 Pressure sensor 125 Discharge pipe 126 Suction port 127 Discharge port 128 Expiration plug 130 Inverter devices 131a and 131b Opening 131 Unit cover 132 Unit base

Claims (9)

A valve body that abuts a valve seat provided in the liquid passage;
A valve stem that moves integrally with the valve body;
A guide member having a hole into which the valve stem is slidably inserted;
A magnet embedded in the valve stem;
With a reed switch that opens and closes by the action of a magnetic field,
A check valve, wherein the reed switch is disposed on a side of the magnet with respect to a moving direction of the valve stem.   The check valve according to claim 1, wherein the reed switch is disposed in parallel with the valve stem.   The check valve according to claim 1 or 2, wherein the magnet is always located inside the guide member.   4. The distance between the position of the valve body when the reed switch is opened and the position of the valve body in contact with the valve seat is 5 mm or less. 5. Check valve described in 1.   The check valve according to any one of claims 1 to 4, wherein the valve stem and the guide member are arranged along a vertical direction. A pump disposed between the suction port and the discharge port;
An electric motor for driving the pump;
A pressure tank for holding the discharge side pressure of the pump;
A check valve according to any one of claims 1 to 5;
And a control device that controls the operation of the pump.   The pump device according to claim 6, wherein the control device includes an inverter.   The pump device according to claim 6 or 7, wherein the check valve is disposed at a position higher than the impeller of the pump. The guide member and the reed switch are attached to a case,
9. A screw thread is formed on an outer peripheral surface of the case, and the case is mounted by being screwed into a screw hole formed in a liquid passage having the valve seat. The pump device according to item.

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