JPH08189570A - Counterflow preventive type drain cock having valve seat - Google Patents

Abstract

PURPOSE: To provide a counterflow preventive drain cock having a valve seat by which a pressure proof inspection up to a water stopcock from a faucet becomes easily possible by using a test pump when a drain cock is installed. CONSTITUTION: In a counterflow preventive drain cock, water is stopped by piece packing 18 where a water stop valve seat 6 between an inflow port 2 and an outflow port 3 of a valve box 1 is installed on the lower end of a piston 21, and a downward check valve seat 7 and a check cylinder 10 having a diameter larger than that are arranged under the water stop valve seat 6. Check packing 23 to block up the check valve seat 7 and check annular packing 24 to slidingly move on the check cylinder 10 are installed, and a check valve 22 to which always upward pressing force is applied by a spring 25 is housed in the valve box 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention type water drain plug having a valve seat, and more particularly to a water drain plug which can be pressure-resistant from a secondary side faucet at the time of installation.

[0002]

2. Description of the Related Art At the time of installation of a water drain plug, in order to inspect for water leakage, it is common to perform a pressure test from the end of the water drain plug, from the faucet to the upstream stop cock with a test pump. . However, in a water drain plug with a check valve built in, the check valve does not act to withstand pressure upstream of the check valve.Therefore, for example, pull out the piston and insert a dedicated pressure-proof piston instead for testing. It took a lot of work, such as having to do it.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is a backflow prevention type in which the pressure can be inspected as it is from the faucet on the secondary side in the test pump even if the backflow prevention valve is provided, especially in the water drain plug having the valve seat. The purpose is to provide a drain plug.

[0004]

Therefore, the water drain plug of the present invention is provided with a check valve seat in the opposite direction to the upper and lower water shutoff valve seats provided between the inlet and the outlet of the valve box, and has a larger size at the lower end than that. Equipped with a non-return cylinder with a large diameter, a non-return packing that closes the non-return cylinder, and a non-return ring packing that slides on the non-return cylinder, and a check valve that is constantly subjected to upward pressure by a spring valve. It is housed in a box.

[0005]

[Function] When water flows, the spring is compressed by the water pressure acting on the check annular packing, the check valve descends, and the check valve seat is in the open state, but it is pressed by the spring at the same time when negative pressure is generated. The check valve rises, the check packing comes into close contact with the check valve seat to prevent backflow of water on the secondary side, and when the negative pressure condition ends and normal pressure acts on the check valve, the check valve Due to the diameter difference between the check valve seat and the check cylinder, the spring is compressed and the check valve descends and returns to the old position. When pressure is applied from the faucet on the secondary side with the test pump, the check valve initially closes the check valve seat, but when pressure is applied, the spring is compressed and the check valve immediately descends. Therefore, there is no problem in the breakdown voltage.

[0006]

EXAMPLES Examples will be described with reference to the drawings. FIG. 1 shows one embodiment of the backflow prevention type water drain plug of the present invention. Reference numeral 1 is a valve box, in which an inlet 2 is provided in the lower side wall, an outlet 3 is provided in the middle part, and a drain port is provided in the upper part. 4, a small-diameter cylinder 5 is provided between the inflow port 2 and the outflow port 3, an upward water stop valve seat 6 is provided at the upper end, and a downward check valve seat 7 is provided at the lower end. Two large-diameter cylinders 8 and 9 are formed above the outlet 3, and a check cylinder 10 having a larger diameter than the check valve seat 7 is coaxially formed below the inlet 2 and at the lowermost end. A circular groove 11 is provided on the outer peripheral portion of the lower end of the check cylinder 10, and the check cylinder 10 is communicated with the check cylinder 10 through a small hole 12. The O-ring 13 is attached to the round groove 11 with some tension, and the O-ring 13 is attached to the inner wall surface 15 of the cap 14 screwed to the lower end of the valve box with a certain crushing allowance.

Inside the valve box 1, the large diameter cylinders 8 and 9 are provided.
2 annular packings 16 and 17 that slide on the bottom are mounted by screws 20 to remove the piece packing 18 that closes the water shutoff valve seat 6 at the lower end and the soft resin collar 19 that slides on the small diameter cylinder 5. The piston 21 is housed so as not to be mounted. A check valve 22 has a check packing 23 for closing the check valve seat 7 at its upper end, and a check cylinder 10 below it.
Attach the non-return annular packing 24 that slides on the cap 1
An upward pressing force is constantly applied by the spring 25 locked to the shaft 4. The valve box 1 is extended by a pipe 26 and connected to an operation unit main body on the ground (not shown), and the piston 21 is extended by a rod 27 and connected to a handle via an operation rod on the ground (not shown).

The figure shows a water flow state, in which pressure water from the inflow port 2 acts on the check annular packing 24 to press the spring 25, and the lower end of the check valve 22 comes into contact with the cap 14 to stop. are doing. At this time, there is no leakage of water upward due to the annular packing 17. To drain water in winter, turn the handle to lower the piston 21. First, the collar 1
When 9 comes into close contact with the small-diameter cylinder 5 to block the water from the inflow port 2 and further descends to separate the annular packing 17 from the cylinder 9, water in the downstream pipe of the outflow port 3 (not shown) While sucking air from the faucet at the end of the pipe, the air begins to be discharged into the ground through the drainage port 4, and finally the piece packing 18 comes into contact with the water shutoff valve seat 6 to completely shut off the water. Even in this state, the check valve 22 is in the same position. Further, since the annular packing 16 is in close contact with the cylinder 8, water does not rise inside the pipe 26.

When a negative pressure is generated in the primary side pipe due to water interruption or the like, the water pressure acting on the check annular packing 24 disappears, so that the check valve 22 is instantly raised by being pressed by the spring 25. Since the check packing 23 is in close contact with the check valve seat 7, the water in the outflow side pipe does not flow back to the inflow side. When the negative pressure is eliminated and the check valve 22 is supplied with water pressure,
Since the diameter of the check cylinder 10 is larger than that of the check valve seat 7,
The water pressure compresses the spring 25 to lower the check valve 22,
Return to the old position. In the unlikely event that water leaks from the check annular packing 24 and the pressure in the lower portion rises, the check valve 22 rises due to the spring 25, closing the check valve seat 7 to prevent water from leaking. Although a situation may occur in which it does not come out, in the present embodiment, the increased pressure causes O from the small holes 12.
Since the ring 13 is deformed and escapes into the ground through the clearance of the screw, the above-mentioned phenomenon does not occur, and the O-ring 13 also prevents the underground wastewater from entering the valve box.

At the time of pressure resistance inspection, the test pump is attached to the faucet at the end of the secondary side as described above, and when the pressure on the secondary side is increased, the check valve 22 compresses the spring 25 and descends. Withstand voltage is applied. The collar 19 is formed of a soft resin to prevent blowout, but it may be formed integrally with the piece packing 18 with rubber, for example. Further, the collar 19 may be omitted, and a spring may be used to stop water and drain water. In this case, the small diameter cylinder 5 is not required. Furthermore, if the pipe 26 is doubled and the valve box for drainage is fixed in the valve box 1,
It is also possible to omit the cylinders 8 and 9 and the annular packings 16 and 17.

[0011]

As described above, in the water tap of the present invention, despite having the check valve, when the pressure is checked from the faucet to the water stop with the test pump at the time of installation,
There is no need to take out the piston one by one and insert a pressure-resistant piston instead, and in addition, loss check because the check valve is always open when water is flowing. Is small, and in particular, a large flow rate can be expected even at low pressure, and vibration unique to the check valve
There is an effect that noise when air enters the secondary side pipe is completely eliminated.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view in a water passing state showing an embodiment of a water drain plug of the present invention.

[Explanation of symbols]

 1 Valve Box 2 Inlet 3 Outlet 4 Drain Port 6 Water Stop Valve Seat 7 Check Valve Seat 8, 9 Cylinder 10 Check Cylinder 11 Round Groove 12 Small Hole 13 O-ring 14 Cap 15 Inner Wall Surface 16, 17 Annular Packing 18 Piece packing 21 Piston 22 Check valve 23 Check packing 24 Check annular packing 25 Spring

Claims (1)

[Claims] 1. An upward water stop valve seat provided between an inlet and an outlet of a valve box having an inlet, an outlet, and a drain on a side wall,
In the drain plug of the type in which the piece packing attached to the lower end of the piston stops water, the valve box has a check valve seat downward and the check cylinder with a larger diameter than that at the lower end. Further, a non-return packing for closing the non-return valve seat and a non-return annular packing for sliding the non-return cylinder are mounted, and the non-return valve which is always subjected to upward pressure by a spring is accommodated. Backflow prevention type drain plug.