JPH10311447A - Return flow preventive drain valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a return flow preventive drain valve which hardly generates a return flow, even though the packing of its check valve is damaged, and has a more excellent reliability. SOLUTION: A bypass 23 leading from an inflow port 2 in the upstream of a check valve to a drain hole 4 is formed in the side of a valve box 1, a drain chamber 24 communicating through an outflow port 3 and an outflow side bypass 25 is provided on the way of the bypass 23, and a drain valve 30 installing a large diameter of pressure receiving packing 29 to cut off the pressure water from the inflow port 2, and a small diameter of drain packing 28 to cut off between the outflow side bypass 25 and the drain hole 4, is housed inside the drain chamber 24.

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 drainage valve, and more particularly to a water drainage valve with more reliable backflow prevention.

[0002]

2. Description of the Related Art Conventionally, this type of drain valve has a check valve housed in the inlet and outlet of a valve box, or as disclosed in Japanese Patent Application No. 6-79480 by the same applicant. In order to facilitate repair and inspection, various types have been used, such as one in which a check valve, which is pressed by a spring, is separately attached to a small diameter portion of a piston.
However, in the case of the above, in the case where the packing of the check valve is damaged or foreign matter is caught in the packing, there is no means for preventing the backflow. As used had reliability issues.

[0003]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a more reliable non-return type water drain valve which is less likely to cause a reverse flow even if the packing is damaged.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention forms a bypass from the inlet upstream of the check valve to the drain at the side of the valve box. A drainage chamber that communicates via the side bypass and a large-diameter pressure-receiving packing that shuts off pressurized water from the inflow port and a small-diameter drainage packing that shuts off between the outflow-side bypass and the drainage port are provided inside the drainage chamber. When a negative pressure is generated due to water interruption on the main pipe side, the drain pressure is pressed by the outflow side pressure, the drain packing opens the outflow side bypass, and the water in the outflow side pipe is drained from the drain port. It is one that can be discharged.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment, the example in which the check valve is mounted or connected to the piston is shown, but it can be accommodated in both the inlet and the outlet. If produced at the inlet, the bypass must be produced upstream. Although a one-way sealing packing having a Y-shaped cross section is used for the check valve and the drain valve to reduce the frictional resistance as much as possible, a normal O-ring can be used. It can also be used to integrally mold the drainage packing.

Instead of moving the operating rod up and down with a screw, the operating rod may be moved up and down with a cam, a lever or the like to reduce the number of rotations of the handle, or may be electrically operated remotely using a motor.

The O-ring of the piston is in close contact with the cylinder between the inflow port and the outflow port to stop water. However, a valve seat is provided instead of the cylinder, and water is stopped by the flat packing attached to the piston. Can also.

[0008]

Embodiments will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a valve box having an inlet 2 and an outlet 3 on a side wall and a drain port 4 on a lower end. Inside, a cylinder 5 is provided above the inlet 2, a cylinder 6 is provided between the inlet 2 and the outlet 3, and a cylinder 7 having a smaller diameter than the cylinders 5 and 6 is provided between the outlet 3 and the drain 4. Formed.

At the upper end, an operation section main body 8 is connected and fixed, and an operation rod 10 having a male screw 9 for operation is housed therein.
A piston 11 is rotatably connected to the lower end of the operating rod 10,
The handle 12 is attached to the upper end.

[0010] The piston 11, the cylinders 5, 6, 7
The annular packings 13, 14, 15 that respectively slide are attached, and the small-diameter portion 1 formed between the annular packings 14, 15 is mounted.
6 is provided with an outer check packing 17 and an inner check packing 18, and the check valve body 2 pressed upward by a spring 19.
Zero check valve 21 is formed. Check valve body 20
Has a notch 22 at the lower end to provide a passage for drainage.

On the side wall of the valve box 1, an inflow-side bypass 23 ',
Forming a bypass 23 consisting of an outflow side bypass 23 ",
A drainage chamber 24 is provided in the middle in the middle, and communicates with the outlet 3 through an outflow-side bypass 25. A small-diameter drain valve seat 26 is formed at the left end of the outflow-side bypass 25, and a large-diameter pressure receiving cylinder 27 is further provided to the left of the small-diameter drain valve seat 26. Drainage room 2
4 includes a small-diameter drain packing 28 and a large-diameter pressure packing 29 that are in close contact with the drain valve seat 26 and the pressure receiving cylinder 27.
Is accommodated, and is prevented from being detached by the plug 31. The inflow-side bypass 23 ′ opens from the inflow port 2 between the plug 31 and the pressure receiving packing 29, and the drainage-side bypass 23 ″ opens from between the pressure receiving packing 29 and the drain valve seat 26 to the drain port 4.

FIG. 1 shows a state in which the faucet at the end of the downstream pipe is closed, that is, a water stop state. When the faucet is opened in this state, the water from the inflow port 2 compresses the spring 19 and reverses. The stop valve body 20 is pushed down, and flows out from the outflow port 3 through the gap between the cylinder 6 and the small-diameter portion 16 to an outflow pipe (not shown). At this time, the annular packings 13 and 15 are in close contact with the cylinders 5 and 7, and the drainage packing 28 and the pressure receiving packing 29 are in close contact with the drainage valve seat 26 and the pressure receiving cylinder 27, so that there is no outflow to other places.

When a negative pressure is generated in the water-flowing state due to, for example, water interruption on the main pipe side, the check valve body 2 is restored by the restoring force of the spring 19.
0 immediately rises and the inner non-return packing 18
Meanwhile, the outer non-return packing 17 is in close contact with the cylinder 6 to prevent backflow, but at the same time, the inside of the inflow-side bypass 23 'is also in a negative pressure state. The outlet side bypass 25 is opened by being pressed by the pressure, and the water in the outlet side pipe is discharged from the drain side bypass 23 ″ to the drain port 4.
Even when a foreign object is caught or damaged in 18, the backflow to the main pipe side can be effectively prevented. When the negative pressure state is eliminated, the drain valve 30 closes the outflow side bypass 25 again by receiving the pressure water from the inflow side bypass 23 ′.

Next, when water is drained from the pipe in winter, when the handle 12 is rotated from the state shown in the figure, the operating rod 10 is lowered while rotating by the male screw 9 for operation, and the piston 11 rotates accordingly. First, the annular packing 14 comes into close contact with the cylinder 6 and blocks water from the inflow port 2. Thereafter, the annular packing 15 is detached from the cylinder 7, and further descends, and the check valve body 20 abuts on the upper end of the cylinder 7 and stops descending. And the inside of the tube is emptied, so that freezing is prevented.

In the winter, when the inside of the pipe freezes due to forgetting to drop water and an abnormal pressure is generated, the abnormal pressure cannot escape to the main pipe side due to the action of the check valve 21 and the pipe may be damaged. However, in the present invention, when the pressure in the outflow-side pipes rises and the pressing forces are reversed, the drain valve 30 opens the drain hole 25 to reduce the abnormal pressure. The above-described accident does not occur because the air escapes to the drain 4.

FIG. 2 shows an outlet side bypass 2 of the drain valve 30.
5 shows an embodiment in which the method of introducing the pressurized water from FIG. 5 is changed. A drain valve 30 is provided on the side of the drain port 4, and the pressure water from the outlet side bypass 25 is supplied to the large-diameter pressure receiving packing 29 and the small-diameter In addition to the opening between the packings 28, a drain valve seat 26 is formed at the left end of the drain side bypass passage 23 "so as to be closed by the drain packing 28. Therefore, the same pressure acts on the pressure receiving packing 29 in a normal state. To prevent excessive deformation of the packing.

FIG. 3 shows another embodiment of the present invention. The valve box 1 has one cylinder 6 between the inflow port 2 and the outflow port 3, and has an inflow-side bypass 23 'and a drain-side bypass. 2
A drain chamber 24 inclined at 45 ° is provided in the middle of the 3 ″ bypass 23, and a hemispherical drain valve seat 26 is formed at the tip of the outflow side bypass 25. The drain valve seat 26 is closed by the drain valve 30. A drain packing 28 in the form of a flat packing is attached, and a projection 32 is provided at the tip to protrude from the outflow side bypass 25.

A small-diameter annular packing 13 ′ is attached to the upper end of the operation section main body 8 so as to block the pressurized water from the inflow port 2. An annular packing 14 that is in close contact with the cylinder 6 is attached to the piston 11, and a flange 33 is formed at the lower end.

The check valve 21 is made of a resin having a specific gravity of less than 1, has an outer check packing 17 attached to the cylinder 6, and has a tapered pressing portion 34 at the lower end.
A locking portion 35 having a slightly larger diameter than the flange portion 33 is provided at the upper end, and a split portion 36 extending from the upper end to below the locking portion 35 is formed, and is connected to the piston 11 so as to be vertically movable.

The figure shows a water stopped state, but when draining, it is preferable to lower the piston 11 as in the case of FIG. Then, the pressing portion 34 of the check valve 21 presses the protrusion 32 to push down the drain valve 30, and the water in the pipe on the outlet 3 side is removed from the outlet side bypass 2.
5. It is discharged from the drain port 4 through the drain side bypass 23 ″.

Since the specific gravity of the check valve 21 is smaller than 1, when a negative pressure is generated on the main pipe side, the check valve 21 immediately rises by buoyancy, and the outer check packing 17 adheres to the cylinder 6 to prevent the check flow. When attaching to the piston 11, the split portion 36
It is sufficient to insert the locking portion 35 so that the locking portion 35 can be pushed.

[0022]

As described above, in the drain valve of the present invention, when a negative pressure is generated on the main pipe side, the drain valve is opened to discharge the water in the outlet pipe to the drain port. Even if the non-return gasket is damaged, the possibility that sewage will be sucked into the main pipe will be reduced and the reliability will be improved. It also has the advantage that the piping can be prevented from being damaged by the pressure increase.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a water stop state according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a main part of another embodiment of the present invention in a water stopped state.

FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention in the same water stopped state.

[Explanation of symbols]

1 valve box 2
Inlet 3 Outlet 4
Drain port 5, 6, 7 Cylinder 8
Operation unit body 9 Male screw for operation 10
Operating rod 11 Piston 12
Handles 13, 14, 15 Ring packing 16
Small diameter part 17 Outer check gasket 18
Inside check packing 19 Spring 20
Check valve element 21 Check valve 22
Notch 23 Bypass 23 '
Inlet side bypass 23 "Drain side bypass 24
Drainage room 25 Outflow side bypass 26
Drain valve seat 27 Pressure receiving cylinder 28
Drainage packing 29 Pressure receiving packing 30
Drain valve 31 Plug 32
Projection 33 Flange 34
Pressing part 35 Locking part 36
Split part

Claims (1)

[Claims] An inflow port and an outflow port are located laterally, and a drain port is located at a lower end. A piston moves up and down in a valve box accommodating a non-return valve therein, and water for drainage and drainage is provided. In removing the valve,
A bypass is formed on the side of the valve box from the inlet on the upstream side of the check valve to the drain, and a drain chamber communicating with the outlet via the outlet bypass is provided in the middle of the bypass. Backflow prevention type drain valve containing a large-diameter pressure-receiving packing that shuts off pressurized water from the outside and a drainage valve that is fitted with a small-diameter drainage packing that shuts off between the outflow side bypass and the drain port.