JPS6111569Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a backflow prevention valve that prevents sewage or hot water from flowing back into the main water pipe when negative pressure is generated in the water main due to a water outage, etc. The present invention relates to a check valve that prevents abnormal pressure increases in pipes during generation or freezing.

Conventionally, when negative pressure occurs on the main pipe side due to a water outage due to waterworks, sewage is sucked in from the outflow side and contaminates the main pipe, or if it is connected to a water heater, hot water flows back and causes damage to the meter, etc. Because of the risk of thermal deformation of plastic parts, it has recently become common practice to install a check valve in the middle of the piping from the main pipe to the terminal equipment to prevent such accidents.

However, when such devices are installed in the middle of the piping, the abnormally increased pressure caused by water hammer, which occurs when an antifreeze faucet or faucet is closed, does not escape to the upstream side of the check valve. As a result, the inside of the pipe remains in an abnormal pressure state until the next time the water is turned on.In addition, in cold regions, if the inside of the pipe freezes due to, for example, forgetting to turn on the antifreeze faucet,
The abnormally increased pressure due to freezing does not escape to the upper end of the check valve due to the action of the check valve, which may cause pipe joints to loosen, causing water leaks, or causing accidents such as pipes or valves to explode. I'm getting used to it.

In view of the above, the purpose of the present invention is to provide a check valve that completely prevents the above accidents by incorporating a kind of safety valve mechanism in the check valve itself to release abnormal pressure to the upstream side. ,
The basic configuration of the present invention for this purpose is as follows.

That is, a valve body having a cylinder inside;
A packing groove for installing a rubber annular packing that is in constant contact with the cylinder and detached from the cylinder when water is flowing; an inflow side and an outflow side flange are provided on both sides of the packing groove; It consists of a valve body in which a part of the circumference of the flange is cut out to reach the gasket groove to form a relief part for the annular gasket between it and the cylinder, and when negative pressure is generated due to water outage, etc. The gasket adheres tightly to the cylinder to prevent dirty water or hot water from flowing back into the main pipe, and when an abnormal pressure rise occurs due to water hammer or freezing, the annular gasket fits into the relief part at a certain pressure. It is deformed in such a way that the rising pressure is released to the upstream side.

The present invention will be described below with reference to embodiments shown in the drawings.

Figure 1 shows an example of a check valve placed in a meter box, with a meter on the inlet groove 2 side provided in the valve body 1 and an antifreeze faucet on the outlet 3 side. Connect the service pipe. A cylinder 4 and a bulging space 5 having a larger diameter than the cylinder 4 are provided inside, and a spring seat 6 is provided adjacent to the outlet 3 at the end thereof. The valve body 7 accommodated in the valve body 1 has a packing groove 9 for mounting a rubber annular packing 8 that slides on the cylinder 4, and has an inflow side flange 10 and an outflow side flange 11 on both sides thereof. In addition, a guide part 12 for the cylinder 4 when the valve body 7 reciprocates is placed on the upstream side of the inflow side flange 10, and the outflow side flange 1
Several spring guide parts 13, which also serve as stoppers when the valve body 7 moves at its maximum, are protruded from the downstream side of the valve body 1. is locked to the spring seat 6,
The valve body 7 is always subjected to a rightward force by the spring 14 guided by the spring guide part 13, and when the water is not flowing, that is, the water is stopped, the annular gasket 8 is applied to the cylinder 4 as shown in the figure. In this state, the tip of the guide portion 12 comes into contact with a stopper washer 15 housed in the inlet 2 to stop its movement. Furthermore, the valve body 7 is shown in FIG.
As shown in the cross-sectional view of the part, a part of the circumference of the inflow side flange 10 is cut out in a reverse arc shape until it reaches the packing groove 9 to form a relief part 16 of the annular packing 8 between it and the cylinder 4 to prevent abnormalities. When the pressure increases, the annular packing 8 deforms and gets stuck in the relief part 16, and the sealing property of the annular packing 8 against the cylinder 4 is lost under a certain constant pressure.
Abnormally increased pressure is released to the inlet 2 side through the gap between the cylinder in the relief part 16 or its adjacent part and the inflow side collar part 10, and when the pressure inside the pipe decreases, the rubber elasticity of the annular packing 8 itself restores the original state. to maintain a water-tight state. In other words, even if a negative pressure is generated on the inlet 2 side in this state, water will not flow back on the inlet 3 side. If the cross-sectional area of the relief portion 16 is made smaller, that is, if the notch is made smaller, the set relief pressure will be increased, and if it is made larger, the set relief pressure will be lowered. In addition,
In the embodiment, a one-way sealing packing having a Y-shaped cross section that blocks only the flow of water from the outlet 3 to the outlet 2 is used as the ring-shaped packing 8. This design reduces the frictional resistance between the valve and the valve, and also takes into account the swelling of the gasket due to aging to ensure smooth operation.
This is intended to further increase the adhesion to the cylinder 4 when the pressure on the side becomes higher than that on the inlet 2 side, but a ring-shaped packing such as an ordinary O-ring may also be used.

FIG. 3 shows another embodiment of the present invention, and to describe the differences from the one in FIG. 1, first, the outflow side flange 11 of the valve body 7 is uniform as shown in FIG. The guide portion 12 is not formed in an annular shape, but is formed into four protrusions that protrude from the extension of the packing groove 9, and extends from the outlet side collar portion 11 toward the outlet 3 side. , is pressed by a spring 14 that is engaged with a rubber bush 17, and the outflow side flange 11 comes into contact with the left end of the cylinder 4, so that the valve body 7 is stopped.

Therefore, the valve body 7 reciprocates using the side wall of the bulging space 5 as a guide, and at the maximum flow rate, the guide portion 12 comes into contact with the bush 17 and stops moving to the left. Note that the bushing 17 may be made of plastic or metal, but if it is made of rubber, the valve body 1 and the bushing 1
It is convenient because there is no need to provide any other sealing means between the openings 7 and 7, and there is no need to use a separate seal when connecting the outlet 3 side to the piping. The inflow side flange 10 is notched in a reverse arc shape to form a relief part 16 between it and the cylinder 4, as in the case of FIG.

In the above embodiments, the non-return valve of the present invention has been explained as being connected as a unit after the meter, but it can be installed anywhere upstream of a terminal device such as a faucet, and it can be attached to the faucet itself. It is also possible to form it integrally with, for example, a pressure reducing valve, antifreeze faucet, meter, water stop valve, water distribution faucet, etc.
The figure shows what is incorporated into the valve body of an antifreeze faucet.

In FIG. 4, the valve body 1 has an inlet 2, an outlet 3, and a drain 18 in order from the bottom on the side wall, and inside the cylinder 4, an annular packing 8 that is attached to the valve body 7 slides. Cylinder 19, 20, 21
make a profit. The piston 23, which attaches the valve body 7 to its narrow diameter portion 22, is connected to the cylinders 19, 2 on the outside.
Four O-rings 24, 25, 26, and 27 are attached to slide on the O-rings 0, 4, and 21, respectively, and an O-ring 28 is attached to the narrow diameter portion 22. The narrow diameter portion 22
The valve body 7, which guides and moves up and down, is equipped with a one-way sealing annular packing 29 on the inside that tightly contacts the narrow diameter portion 22, and is pressed against the O-ring 28 by the spring 14 to prevent it from moving downward any further. I try not to. In other words, in this state, the annular packing 8 is attached to the cylinder 4, and the annular packing 29 is attached to the narrow diameter portion 2.
2, and the valve body 7 is pressed by the O-ring 28. Therefore, even if negative pressure is generated on the inlet 2 side, the water on the outlet 3 side will not flow backwards. It is also possible to omit either the annular packing 29 or the O-ring 28.

When you open the faucet at the end of the downstream piping from the state shown in the diagram,
The valve body 7 compresses the spring 14 and rises due to water pressure,
The annular gasket 8 separates from the cylinder 4 to form a water passage, and water is discharged from the faucet. When the piston 23 is raised from this state, first the O-ring 2
6 is in close contact with the cylinder 4 and the O-ring 27 blocks water from the inlet 2, and when it is further raised, the O
The ring 24 comes into close contact with the cylinder 19, and then O
Since the ring 25 is detached from the cylinder 20, the water in the outlet pipe leading to the faucet is discharged underground from the drain port 18. In other words, it becomes a draining state. In the drain state, the valve body 7 is separated upward from the cylinder 4, but the O-rings 26 and 17 keep the valve body 7 away from the inlet 2.
Of course, even if negative pressure is generated on the side, the water on the outflow port 3 side will not flow back. As shown in FIG. 5, the inflow side flange 10 of the valve body 7 is cut flat to form a relief part 16 between it and the cylinder, and is easier to process than the one shown in FIG. It is easy and does not require post-processing such as removal.

According to the above embodiment, from the valve body 1 to the piston 2
There is an advantage that the check valve can be easily repaired by pulling out the valve. Note that the spring 14 may be omitted and the valve body 7 may be caused to fall by its own weight.
In addition, the shape of the relief portion 16 can be changed in various ways, such as a fan shape or a crescent shape, and it is also possible to provide notches not only at one location but at two or several locations.

As explained above, the present invention has a very simple structure in which a part of the inlet side flange of the valve body is cut out to form a relief part for the annular packing between the valve body and the cylinder. This eliminates accidents where abnormally increased pressure is released to the upstream side, causing damage to the meter, antifreeze faucet, or piping, or causing water leakage from their connections. There is no need to release the abnormally increased pressure to another location via a pipe connected to the safety valve, which reduces costs. There is no need to take this into account, and the valve uses a ring-shaped gasket that fits tightly to the cylinder to shut off water.
It is possible to provide a check valve that has a greater sealing effect than a conventional check valve that shuts off water by bringing a flat packing into close contact with the valve seat.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figures are a sectional view of the A-A portion of the valve body in Figure 1, Figure 3,
FIG. 4 is a sectional view showing another embodiment of the present invention, and FIG.
The figure is a sectional view of the BB portion of the valve body in FIG. 4. 1...Valve body, 2...Inflow port, 3...Outflow port,
4... Cylinder, 8... Annular packing, 9... Packing groove, 10... Inflow side flange, 11... Outflow side flange, 14... Spring, 16... Relief part, 18...
Drain port, 19, 20, 21...Cylinder, 22...
...Small diameter part, 23...Piston, 24, 25, 2
6, 17...O-ring, 29...annular packing.

Claims (1)

[Scope of utility model registration request] The valve body includes a valve body having a cylinder inside, a gasket groove for mounting a rubber annular gasket that tightly contacts the cylinder, and a valve body having an inflow side and an outflow side collar portion on both sides of the gasket groove, The valve body has a part of the circumference of the inflow side flange section cut out to reach the packing groove to form a relief part for the annular packing between the valve body and the cylinder, and to reduce the abnormally increased pressure generated on the outflow side. A non-return valve characterized by allowing water to escape to the inflow side.