JPH083478Y2 - Backflow prevention device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention mainly relates to a backflow prevention device installed in a water pipe of a house or a building lined up on a platform in a hill.

[Conventional technology]

As a backflow prevention device used when water is supplied directly from a main pipe to each floor of a building, etc., a valve box having a discharge port formed between an upstream side opening end and a downstream side opening end, and the valve box Is provided at the upstream open end of the first check valve that allows the flow of fluid flowing from the upstream side to the downstream side and blocks the flow of fluid from the downstream side to the upstream side, and is provided at the downstream open end of the valve box. Between the first check valve and the second check valve, which allows the flow of the fluid flowing from the downstream side to the downstream side and blocks the flow of the fluid flowing from the downstream side to the upstream side, and is connected to the discharge port. Provided between the upstream chamber and the upstream chamber that communicates with the upstream side of the first check valve, and when the difference between the pressure of the upstream chamber and the pressure of the intermediate chamber exceeds a predetermined value. When moving from the upstream chamber side to the intermediate chamber side and the difference between the upstream chamber pressure and the intermediate chamber pressure becomes smaller than a predetermined value, the intermediate chamber side From the intermediate chamber side to the upstream chamber side, and the movable member connected to the movable member closes the discharge port by the movement of the movable member from the upstream chamber side to the intermediate chamber side, and the movable member moves from the intermediate chamber side to the upstream chamber side. There is known one provided with an on-off valve for opening a discharge port (Japanese Patent Laid-Open No. 59-180174).

[Problems to be solved by the device]

The check valve has a structure in which the valve body of the check valve is pressed against the valve seat of the valve box by a pressing spring to obtain a required pressure loss.

However, in the conventional backflow prevention device, since the pressing force of the pressing spring could not be adjusted, for example, the backflow prevention device was installed from the lower floor of the building to the upper floor in order of magnitude of pressure loss, and In order to equalize the water pressure, it is necessary to prepare various kinds of backflow prevention devices with different pressure loss, that is, the force of the pressing spring, and when the water pressure of the main pipe is changed greatly, There was a problem that the backflow prevention device with a pressure loss corresponding to the water pressure had to be replaced.

The present invention provides a backflow prevention device that can freely change the pressing force of a pressing spring and can compress the pressing spring to easily assemble them when the valve body and the valve seat are assembled into a unit. The purpose is to do.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a valve box having a discharge port formed between an upstream opening end and a downstream opening end,
A first check valve provided at an upstream opening end of the valve box and allowing a flow of a fluid flowing from an upstream side to a downstream side to prevent a fluid flow from the downstream side to the upstream side; and a downstream opening end of the valve box. Between the first check valve and the second check valve, which is provided in the second check valve for allowing the flow of the fluid flowing from the upstream side to the downstream side and blocking the flow of the fluid flowing from the downstream side to the upstream side. It is provided between the intermediate chamber formed in series with the discharge port and the upstream chamber provided in communication with the upstream side of the first check valve, and the difference between the pressure of the upstream chamber and the pressure of the intermediate chamber has a predetermined value. A movable member that moves from the upstream chamber side to the intermediate chamber side when it exceeds, and a movable member that moves from the intermediate chamber side to the upstream chamber side when the pressure difference between the upstream chamber and the intermediate chamber becomes smaller than a predetermined value; The movable member is connected to the member, the outlet is closed by the movement of the movable member from the upstream chamber side to the intermediate chamber side, and the movable member is moved from the intermediate chamber side to the upstream chamber side. A check valve having an opening / closing valve that opens a discharge port by movement, wherein at least one of the first check valve and the second check valve is pressed against a valve seat to stop the flow of fluid. The configuration includes a body, a pressing spring that presses the valve body against the valve seat, and an adjusting member that adjusts the pressing force of the pressing spring.

[Action]

When a backflow prevention device with a large pressure loss is required, the adjusting member of the backflow prevention device is operated to increase the pressing force of the pressing spring. Further, in order to reduce the pressure loss, the pressing force of the pressing spring is reduced by adjusting the adjusting member. Since the pressing force of the pressing spring can be freely changed by the adjusting member in this manner, it is not necessary to use many kinds of backflow preventing devices even when the water pressures on the respective floors of the building are made equal.

〔Example〕

The accompanying drawings show an embodiment of the present invention, in which the present check device includes a valve box 1, a first check valve 2, a second check valve 3, a movable member 4, and an opening / closing valve 5. Is the main subject.

The valve box 1 is screwed to a valve box body 6 having an opening 6c and a discharge port 6d between an upstream opening end 6a and a downstream opening end 6b, and a female screw 6e of the upstream opening end 6a. And a lid 9 which covers the mouth portion 6c of the valve box body 6 and is detachably attached to the valve box body 6 with bolts 8. The mouth 6c of the valve body 6 and the outlet 6d face each other vertically.

Further, the first check valve 2 includes a valve seat member 11 and a bracket 12
A valve body 13, a pressing spring 14, and an adjusting member 15. The valve seat member 11 is formed in an annular shape and has a valve seat 11a on one end surface and a plurality of (four in the figure) locking pieces 11b projectingly provided on the outer peripheral surface with a required gap 11c. ing. The valve seat member 11 is liquid-tightly fitted in the first fitting hole 7a of the base 7. The bracket 12 has a female screw cylinder 12a at the center of one end, and the locking piece 1 of the valve seat member 11 is provided on the inner peripheral surface of the other end.
The same number of locking claws 12b as that of 1b are provided so as to project with a gap 12c. The protrusion width of the locking piece 11b of the valve seat member 11 is the width of the bracket 1
2 is smaller than the width of the clearance 12c, and the locking claw of the bracket 12
The protruding width of 12b is smaller than the width of the gap 11c of the valve seat member 11, and the valve seat member 11 and the bracket 12 have a mating gap 12c between the locking piece 11b and the locking claw 12b. By engaging with 11c and rotating relatively, locking piece 11b and locking claw 1
2b and 2b are locked to each other and are integrally coupled. Bracket 12
Is fitted into the second fitting hole 7b of the base 7.

The valve body 13 includes a seat 13 on a valve body 13b having a guide rod 13a.
Attach c with screws 16. The seat 13c may be attached to the valve body 13b by lining or bonding with an adhesive. The seat 13c is made of a flexible material such as rubber or synthetic resin. The adjusting member 15 is composed of a male screw having a guide hole 15a, and is provided with a guide rod 13a of the valve body 13.
Is inserted into the guide hole 15a and is screwed into the female screw cylinder 12a so as to be adjustable. The pressing spring 14 is mounted between the valve body 13b and the adjusting member 15, and presses the seat 13c of the valve body 13 against the valve seat 11a.

The outer diameter of the valve seat member 11A of the second check valve 3 is larger than that of the valve seat member 11 of the first check valve 2, and the locking claw 12 of the bracket 12 is provided.
Since the structure is the same as that of the first check valve 2 except that it is formed to have the same outer diameter as that of the b portion, the same reference numerals are given and detailed description thereof is omitted. The second check valve 3 includes a valve box body 6
The bracket 12 is brought into contact with the rim 6f of the valve body 6 and is fitted into the fitting hole 6g of the valve body 6.

The first check valve 2 and the second check valve 3 can be fitted into the fitting holes 7a, 7b, 6g by inserting them into the valve body 6 from the mouth 6c. An intermediate chamber is provided between the first check valve 2 fitted in the fitting holes 7a, 7b and the second check valve 3 fitted in the other fitting hole 6g.
6h is formed. The intermediate chamber 6h communicates with the mouth 6c and the outlet 6d. Intermediate member between the first check valve 2 and the second check valve 3
17 is inserted. The intermediate member 17 has contact seats 17a and 17a for contacting the female screw cylinder 12a of the first check valve 2 and a contact seat 17b for contacting the valve seat member 11A of the second check valve 3. However, withdrawal of the first check valve 2 to the downstream side (right side in FIG. 1) and withdrawal of the second check valve 3 to the upstream side are prevented. Intermediate member 17
Can also be taken in and out from the valve box body 6 through the mouth portion 6c.

The movable member 4 includes a diaphragm 18, a valve plate 19, and a movable rod.
20 and a piston 21. The piston 21 is a movable rod 20 that is penetrated through a small hole in the center of the diaphragm 18 and the valve plate 19.
The diaphragm 18 and the valve plate 19 are liquid-tightly fixed to the movable rod 20 by being screwed to the threaded portion 20a. The diaphragm 18 is liquid-tightly attached to the periphery of the diaphragm 18 between the valve body 6 and the lid 9, and divides the upstream chamber 9a on the lid 9 side and the intermediate chamber 6h. The valve plate 19 is provided in the upstream chamber 9a with its peripheral portion facing the valve seat surface 9b of the lid 9, and the piston 21 is provided in the cylinder of the lid 9.
It is inserted in 9c in a liquid-tight manner. The cylinder 9c of the lid 9 is open to the atmosphere through the hole 9d. The upstream chamber 9a communicates with the upstream side of the first check valve 2 via the lid 9, the valve box body 6, and the communication holes 9e, 6i, 7c formed in the base 7.

The on-off valve 5 includes a valve seat member 22, a valve body 23, a receiving seat 24, and a spring 25. The valve seat member 22 includes a valve seat 22a and a through hole 22b.
And a guide hole 22c, and a fitting hole 6 provided in the discharge port 6d.
It is fitted in k in a liquid-tight manner from the mouth portion 6c side. The valve body 23 is composed of a valve body 23a and a seat 23b made of rubber or the like attached to the valve body 23a by a lining or an adhesive, and is fitted to the lower end of the movable rod 20 following the receiving seat 24, and by a nut 26. It is liquid-tightly fixed to the movable rod 20 together with the receiving seat 24. A spring 25 is inserted between the valve seat member 22 and the receiving seat 24 to press the valve seat member 22 against the fitting hole 6k and urge the movable rod 20 upward. A rod 20b is projectingly provided at the lower end of the movable rod 20, and is inserted into the guide hole 22c of the valve seat member 22. The valve box body 6 has a hole 6m communicating with the communication hole 6i and an intermediate chamber 6m.
Hole 6n leading to 6h, and hole leading to the downstream side of the second check valve 3
6p is drilled, and cocks 27, 28, 29 are placed in each hole 6m, 6n, 6p.
Is provided. Further, the lid 9 is formed with an air vent hole 9f communicating with the communication hole 9e and is closed by a plug 30. Connection screws 7d and 6q are engraved on the mouthpiece 7 and the downstream opening end 6b of the valve box body 6.

Next, the operation of the backflow prevention device according to the present invention constructed as above will be described.

Screw backflow prevention device assembled as shown in Fig. 1
Connect to a water pipe (not shown) using d and 6q. At the time of connection, the plug 30 is removed, air is extracted from the hole 9f, and water is put in the upstream chamber 9a and placed. In this connected state, when water pressure is applied to the upstream side of the valve box 1, that is, the portion of the mouthpiece 7, water will pass through the communication hole.
It flows through 7c, 6i, 9e to the upstream chamber 9a, pushes the valve plate 19 away from the valve seat surface 9b, and pushes the diaphragm 18 downward to lower the movable rod 20 against the elasticity of the spring 25. As a result, the seat 23b of the valve body 23 is pressed against the valve seat 22a and the discharge hole 6d
Close.

When the water pressure further increases, the water pushes the valve body 13 of the first check valve 2 to the right in FIG. 1 against the elastic force of the pressing spring 14 to enter the intermediate chamber 6h, and the valve of the second check valve 3 is further pushed. The body 13 is also pushed open and flows downstream. At this time, the water pressure in the intermediate chamber 6h is 1st check valve 2
Since the pressure is reduced by, a differential pressure is generated between the upper and lower sides of the diaphragm 18. Since the spring 25 is designed to be weaker than this pressure difference, the on-off valve 5 normally does not open under running water.

When the faucet (not shown) provided on the downstream side is closed to stop the flow of water, the valve bodies 13 of the check valves 2 and 3 are immediately pressed against the valve seat 11a by the pressing spring 14 and the valve seat 11a of FIG. It becomes a state. However, since the differential pressure generated by the first check valve 2 is still applied to the diaphragm 18, the open / close valve 5 remains closed.

If the upstream side becomes negative pressure for some reason while the downstream faucet is open, the valve element 13 is pressed against the valve seat 11a by the action of the pressure spring 14 and the suction action by the negative pressure. When the box 1 is closed, the diaphragm 18 is sucked upward as shown in FIG. 1, and the movable rod 20 is raised in cooperation with the spring 25 to open the on-off valve 5. At this time, the valve plate 19 is pressed against the valve seat surface 9b,
Close the part.

For example, when the rubber hose attached to the faucet is hung on the bottom of the bathtub and water is being added, negative pressure may occur on the upstream side as described above, and the check valves 2 and 3 may not close due to dust, etc. Even if it occurs, the open / close valve 5 is opened to open the intermediate chamber 6h to the atmosphere, so that the dirty water in the bathtub does not flow out to the upstream side and pollute clean water. Further, since the valve plate 19 is in close contact with the valve seat surface 9b and closes the portion, even if the diaphragm 18 has a hole, the water on the downstream side will pass through the upstream chamber 9a and the communication holes 9e, 6i, 7c. It does not flow through to the upstream side.

When it is necessary to change the pressure loss of the check valves 2 and 3, the main plug (not shown) is operated to close the water pipe, and then the bolt 8 is loosened and the lid 9 is removed to remove the movable member. 4 and the intermediate member 17 are pulled out upward from the mouth portion 6c. Next, the check valves 2 and 3 are pulled out from the valve box body 6, and the adjusting member 15 is advanced and retracted to adjust the pressing force of the pressing spring 14 to change the pressure loss. Usually first
The pressure spring 14 of the check valve 2 is the pressure spring 14 of the second check valve 3.
The pressing force is adjusted to be stronger than that.

In addition, the valve bodies 13 of the check valves 2 and 3 have the valve body 13b and the guide frame 12
Since the guide rod 13a is guided by the guide hole 15a while being guided by d, the movement is smooth and does not rattle. Further, since the valve body 23 of the on-off valve 5 is also guided by the rod 20b by the guide hole 22c and the piston 21 by the cylinder 9c, the movement thereof is smooth and does not rattle.

The cocks 27, 28, 29 are used when checking whether or not the check valves 2, 3 and the diaphragm 18 etc. normally operate.

When the valve seat members 11 and 11A of the check valves 2 and 3 and the bracket 12 are fitted to each other, both members are fitted while the force of the pressure spring 14 is weakened by the adjusting member 15, and then the adjusting member 15 is used. The pressing force of the pressing spring 14 is set to a predetermined value.

[Effect of device]

As described above, the backflow prevention device according to the present invention is
A valve box having a discharge port formed between an upstream opening end and a downstream opening end, and a flow of fluid flowing from the upstream side to the downstream side provided at the upstream opening end of the valve box and allowing the flow from the downstream side to the upstream side. Check valve for blocking the flow of fluid toward the side, and allowing the flow of fluid flowing from the upstream side to the downstream side at the downstream opening end of the valve box and blocking the flow of fluid flowing from the downstream side to the upstream side Upstream of the second check valve, the intermediate chamber formed between the first check valve and the second check valve in communication with the discharge port, and the upstream side of the first check valve in communication with each other. It is provided between the upstream chamber and the intermediate chamber and moves from the upstream chamber side to the intermediate chamber side when the difference between the upstream chamber pressure and the intermediate chamber pressure exceeds a predetermined value, and the difference between the upstream chamber pressure and the intermediate chamber pressure reaches a predetermined value. A movable member that moves from the intermediate chamber side to the upstream chamber side when the value becomes smaller than the value, and the movable member that is connected to the movable member and moves from the upstream chamber side to the intermediate side. A backflow prevention device including an opening / closing valve that closes the discharge port by moving the movable member toward the side and opens the discharge port by moving the movable member from the intermediate chamber side to the upstream chamber side. At least one check valve of the valve includes a valve body that is pressed against a valve seat to stop the flow of fluid, a pressing spring that presses the valve body against the valve seat, and an adjusting member that adjusts the pressing force of the pressing spring. Since the configuration is provided, it is possible to finely adjust the pressure loss to a desired size by changing the pressing force of the pressing spring. Therefore, even if the water pressure on each floor of the building is made equal, only one kind of backflow prevention device needs to be prepared, which is easy to handle and economical.

Further, when the valve seat member and the bracket of the check valve are fitted to each other to assemble them integrally, the pressure spring needs to be compressed, which is not easy in the case of a large-sized backflow prevention device, but the backflow prevention device of the present invention. In the above, since the force of the pressing spring can be weakened by the adjusting member, the check valve can be easily assembled.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention. FIG. 1 is a sectional view of the present backflow prevention device, FIG. 2 is a plan view, and FIG. 3 is a front view in which the right half of the valve seat member is omitted. 4 is a partially cutaway front view of the bracket, FIG. 5 is a front view of the intermediate member, FIG. 6 is a sectional view of the intermediate member, and FIG. 7 is a partially cutaway plan view of the intermediate member with the lower half omitted. Is. 1 ... Valve box, 2 ... First check valve 3 ... Second check valve, 4 ... Movable member 5 ... Open / close valve, 6a ... Upstream opening end 6b ... Downstream opening end, 6d …… Discharge port 6h …… Intermediate chamber, 9a …… Upstream chamber 11a …… Valve seat, 13 …… Valve element 14 …… Pressing spring, 15 …… Adjustment member

Claims (1)

[Scope of utility model registration request] 1. A valve box having a discharge port formed between an upstream opening end and a downstream opening end, and a flow of fluid flowing from upstream to downstream provided at the upstream opening end of the valve box. A first check valve that allows the flow of the fluid from the downstream side to the upstream side.
A second check valve provided at the downstream open end of the valve box, allowing a flow of fluid flowing from the upstream side to the downstream side and blocking a flow of fluid flowing from the downstream side to the upstream side; the first check valve and the second check valve. It is provided between an intermediate chamber that is formed between the check valve and the discharge port, and an upstream chamber that is provided at the upstream side of the first check valve.
When the difference between the pressure in the upstream chamber and the pressure in the intermediate chamber exceeds a predetermined value, the pressure moves from the upstream chamber side to the intermediate chamber side, and when the difference between the pressure in the upstream chamber and the pressure in the intermediate chamber becomes smaller than the predetermined value. A movable member that moves from the intermediate chamber side to the upstream chamber side, and the movable member is connected to the movable member, and the discharge port is closed by the movement of the movable member from the upstream chamber side to the intermediate chamber side, and the movable member moves from the intermediate chamber side to the upstream chamber side. In a check valve for opening the discharge port by the movement of the check valve, at least one of the first check valve and the second check valve is pressed against the valve seat to stop the flow of fluid. Valve body,
A backflow prevention device comprising: a pressing spring that presses the valve element against a valve seat; and an adjusting member that adjusts the pressing force of the pressing spring.