JP3918226B2 - Backflow prevention type water drain valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backflow prevention type water drain valve, and more particularly to a water drain valve that further ensures backflow prevention.
[0002]
[Prior art]
Conventionally, this type of drain valve has been easily repaired and inspected, such as those in which a backflow prevention valve is accommodated in the inlet and outlet of the valve box or Japanese Patent Application No. 6-79480 by the same applicant. Various types have been used, such as one in which a backflow prevention valve pressed by a spring is attached to the small diameter portion of the piston. However, in the case of the above, there is no means to prevent backflow when the packing of the backflow prevention valve is damaged or foreign matter is caught in the packing, especially for directly connected water supply. There was a problem with reliability to use as.
[0003]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a more reliable backflow prevention type drain valve that is less likely to cause backflow even if the packing is damaged.
[0004]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention forms a bypass from the inlet on the upstream side of the backflow prevention valve to the drain outlet on the side of the valve box, and communicates with the outlet via the outlet and the outlet bypass in the middle. A large-diameter pressure-receiving packing that shuts off pressure water from the inlet and a drain valve that is fitted with a small-diameter drain packing that shuts off the outlet-side bypass and drain outlet are housed in the main pipe. When a negative pressure is generated due to water breakage or the like on the side, the drainage packing is pressed by the outflow side pressure to open the outflow side bypass so that the water in the outflow side pipe can be discharged from the drain port.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the embodiment, an example in which a backflow prevention valve is mounted or connected to the piston is shown, but this can be accommodated in both the inlet and the outlet. In case of opening at the inlet, the bypass must be made from the upstream side. The backflow prevention valve and the drainage valve use a one-way sealable packing with a Y-shaped cross section to minimize the frictional resistance as much as possible, but a normal O-ring can also be used, and a diaphragm can be used. It can also be used to integrally mold the drainage packing.
[0006]
Instead of moving the operating rod up and down with a screw, it can be moved up and down with a cam, a lever, etc. to reduce the number of rotations of the handle, and it can be electrically operated remotely using a motor.
[0007]
Although the piston O-ring is in close contact with the cylinder between the inlet and outlet, water can be stopped, but a valve seat can be provided instead of the cylinder, and water can be stopped by a flat packing attached to the piston.
[0008]
【Example】
The embodiment will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a valve box, which has an inlet 2 and an outlet 3 on a side wall, and a drain outlet 4 on a lower end. Inside, the cylinder 5 is coaxially positioned above the inlet 2, the cylinder 6 is between the inlet 2 and the outlet 3, and the cylinder 7 having a smaller diameter than the cylinders 5, 6 is coaxially disposed between the outlet 3 and the outlet 4. To form.
[0009]
An operation unit body 8 is connected and fixed to the upper end, and an operation rod 10 having an operating male screw 9 is accommodated therein. A piston 11 is rotatably connected to the lower end of the operation rod 10, and a handle 12 is attached to the upper end. Install.
[0010]
The piston 11 is fitted with annular packings 13, 14, and 15 that slide on the cylinders 5, 6, and 7, respectively, and a small-diameter portion 16 formed between the annular packings 14 and 15 has an outer check packing 17 and an inner packing. A check packing 18 is attached, and a check valve body 20 pressed upward by a spring 19 is provided to form a check valve 21. The check valve body 20 has a notch 22 at the lower end to provide a passage for drainage.
[0011]
A bypass 23 composed of an inflow side bypass 23 ′ and an outflow side bypass 23 ″ is formed on the side wall of the valve box 1, and a drainage chamber 24 is provided laterally between the bypass 23 and communicated with the outflow port 3 through the outflow side bypass 25. A small-diameter drainage valve seat 26 is formed at the left end of the outflow side bypass 25, and a large-diameter pressure receiving cylinder 27 is provided on the left side of the drainage bypass 25. The drainage chamber 24 is in close contact with the drainage valve seat 26 and the pressure-receiving cylinder 27. A drain valve 30 for mounting a small-diameter drain packing 28 and a large-diameter pressure receiving packing 29 is accommodated so as not to be detached by a plug 31. An inflow side bypass 23 'is provided between the plug 31 and the pressure receiving packing 29 from the inlet 2. The drain side bypass 23 ″ opens from the space between the pressure-receiving packing 29 and the drain valve seat 26 to the drain port 4.
[0012]
The figure shows a state in which the faucet at the end of the downstream side pipe is closed, that is, a water stoppage state. When the faucet is opened in this state, water from the inflow port 2 compresses the spring 19 to check the 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 side pipe (not shown). At this time, the annular packings 13 and 15 are in close contact with the cylinders 5 and 7, 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, and there is no outflow to other places.
[0013]
When negative pressure is generated due to water breakage or the like on the main pipe side in the water flow state, the check valve body 20 immediately rises due to the restoring force of the spring 19, and the inner check gasket 18 is placed on the small diameter portion 16 on the outer check. The 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, so that the pressure receiving packing 29 reduces sealing and the drain valve 30 is pressed by the outflow side pressure. The outflow side bypass 25 is opened, and the water in the outflow side pipe is discharged from the drain side bypass 23 "to the drain port 4. That is, when foreign matter is caught in the check packings 17 and 18, or is damaged. When the negative pressure state is resolved, the drain valve 30 receives the pressure water from the inflow side bypass 23 'and closes the outflow side bypass 25 again. .
[0014]
Next, in order to drain water 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 being rotated by the operating male screw 9, and the piston 11 is lowered without being rotated accordingly. First, the annular packing 14 is in close contact with the cylinder 6 to block water from the inlet 2. Thereafter, the annular packing 15 is detached from the cylinder 7 and further descends so that the check valve body 20 comes into contact with the upper end of the cylinder 7 and stops descending. Water in the outflow side pipe passes through the notch 22 and drains 4 As the tube is discharged and the inside of the pipe is emptied, freezing is prevented.
[0015]
In winter, when the water is forgotten to drop and the inside of the pipe freezes and an abnormal pressure is generated, the backflow prevention valve 21 prevents the abnormal pressure from escaping to the main pipe, resulting in damage to the pipe. However, in the present invention, when the pressure in the outflow side pipe rises and the pressing force of each other is reversed, the drain valve 30 opens the drain small hole 25 so that the abnormal pressure is reduced to the drain port 4. The above accident does not occur.
[0016]
FIG. 2 shows an embodiment in which the method of introducing pressure water from the outflow side bypass 25 of the drain valve 30 is changed, but the drain valve 30 is provided on the side of the drain port 4 and the pressure from the outflow side bypass 25 is shown. Water is opened between the large-diameter pressure-receiving packing 29 and the small-diameter drain packing 28, and a drain valve seat 26 is formed at the left end of the drain-side bypass passage 23 ″ so as to be blocked by the drain packing 28. In FIG. 2, the same pressure is applied to the pressure receiving packing 29 so that the packing is not excessively deformed.
[0017]
FIG. 3 shows another embodiment of the present invention, in which the valve box 1 has one cylinder 6 between the inlet 2 and the outlet 3, from the inlet side bypass 23 ′ and the drain side bypass 23 ″. A drainage chamber 24 inclined at 45 ° is provided at the intermediate portion of the bypass 23, and a hemispherical drain valve seat 26 is formed at the tip of the outflow side bypass 25. A flat packing shape for closing the drain valve seat 26 on the drain valve 30. The drainage packing 28 is attached, and a protrusion 32 is provided at the tip so as to protrude from the outflow side bypass 25.
[0018]
A small-diameter annular packing 13 ′ is attached to the upper end portion of the operation portion main body 8 so as to block the pressure 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.
[0019]
The backflow prevention valve 21 is made of a resin having a specific gravity smaller than 1, and is equipped with an outer check packing 17 that is in close contact with the cylinder 6, a tapered pressing portion 34 at the lower end, and a slightly larger diameter than the flange portion 33 at the upper end. The engaging portion 35 is provided, and a split portion 36 extending from the upper end to the lower portion of the engaging portion 35 is formed and connected to the piston 11 so as to be movable up and down.
[0020]
Although the figure shows a water stoppage state, when the drainage state is set, the piston 11 may be lowered as in the case of FIG. 1. First, the annular packing 14 is brought into close contact with the cylinder 6, and the water from the inlet 2. After that, the pressing portion 34 of the backflow prevention valve 21 presses the protrusion 32 and pushes down the drain valve 30, and the water in the pipe on the outlet 3 side passes through the outflow side bypass 25 and the drain side bypass 23 ″. And discharged from the drain port 4.
[0021]
Since the specific gravity of the backflow prevention valve 21 is less than 1, when a negative pressure is generated on the main pipe side, the backflow prevention valve 21 immediately rises by buoyancy, and the outer check packing 17 is in close contact with the cylinder 6 to prevent backflow. What is necessary is just to insert so that the latching | locking part 35 may be pushed down by the split part 36, when attaching to the piston 11. FIG.
[0022]
【The invention's effect】
As described above, in the drain valve of the present invention, when negative pressure is generated on the main pipe side, the drain valve opens, and the water in the outflow side pipe is discharged to the drain port. Even in the case of damage, 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 it can be prevented from being damaged.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view in a water stop state showing an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of an essential part in a water stop state, showing another embodiment of the present invention.
FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention in the same water-stopped state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Valve box 2 Inlet 3 Outlet 4 Drain outlet 5, 6, 7 Cylinder 8 Operation part main body 9 Actuation male screw 10 Operation rod 11 Piston 12 Handle 13, 14, 15 Annular packing 16 Small diameter part 17 Outer non-return packing 18 Inner check packing 19 Spring 20 Check valve body 21 Check valve 22 Notch 23 Bypass 23 'Inflow side bypass 23 "Drain side bypass 24 Drainage chamber 25 Outflow side bypass 26 Drain valve seat 27 Pressure receiving cylinder 28 Drain packing 29 Pressure receiving packing 30 Drain valve 31 Plug 32 Protrusion 33 Gutter 34 Pressing part 35 Locking part 36 Split part

Claims (1)

In the drain valve where the piston moves up and down in the valve box that houses the inlet and outlet on the side and the drain outlet on the lower end and houses the check valve inside, the valve box A bypass from the inlet side upstream of the backflow prevention valve to the drain outlet is formed on the side, and a drainage chamber communicating with the outlet through the outlet bypass is provided in the middle, and the drainage chamber is connected to the inside from the inlet. A backflow prevention type drain valve that houses a large-diameter pressure-receiving packing that shuts off pressure water and a drain valve that is fitted with a small-diameter drain packing that shuts off between the outflow side bypass and the drain port.

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