JPH10195941A - Back flow prevention type antifreeze faucet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform handle operation smoothly during pressureproof test by providing a sealing portion at a lower end portion in a bottom portion of a piston attachment, a self-closing type top packing for closing a valve seat to the outer periphery of a smallest diameter portion formed above the sealing portion, and connecting a check valve body a always pushing downward in a freely movable state up-and-down by a self-locking spring. SOLUTION: Drain-ring shaped packing 10, 11 and a water stop ring-shaped packing 12 are attached to the outer periphery of a piston 9, and a water stop packing 13 and a small diameter portion 14 are provided below the packing. The check valve body 18 forms a water stop portion 19 at the upper end, has a water stop top packing 20 at the lower end and a self-locking ring-shaped packing 21 inside, and a self-locking spring 22 secured to the piston 9 always applies a pushing force downward. A piston 9 is lowered by a constant distance, and if a pressure test is conducted in a state where the drain ring-shaped packing 11 is kept adhered to a drain cylinder 7 and the water stop ring-shaped packing 12 has not adhered to a water stop cylinder 6 yet and the self-locking ring-shaped packing 21 is separated from a sealing portion 18 to the outside of a pressure introducing potion 15, a pressure applied from the faucet side by a test pump reaches a stop cock through a pressure introducing portion 15, and handle operation can be performed smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention device having a valve seat which allows a pressure test at the time of construction to be completed by a simple operation, and allows a handle operation to be easily performed even when a faucet is closed during drainage. Type antifreeze hydrant.

[0002]

2. Description of the Related Art Conventionally, when constructing an antifreeze water tap, in order to perform a pressure test in the pipe, air is discharged from the pipe while flowing water from a faucet at the end of the pipe on the outflow side, and the water stopcock on the upstream side is closed. Then remove the faucet, attach a pressure gauge, apply water pressure with the test pump, and check with the pressure gauge whether there is any water leakage to the stopcock. However, although there is no problem in the case of a normal antifreeze hydrant, in the case of an antifreeze hydrant incorporating a check valve, the check valve operates to move upstream from the antifreeze hydrant, that is, into the primary-side inlet pipe. Is not subjected to pressure, and a pressure test cannot be performed. Therefore, for example, the piston has to be pulled out, and a piston dedicated to pressure resistance must be inserted and tested instead.

[0003] Separately, at the time of draining, if the handle is operated with the faucet closed, the check valve is also activated and the secondary side pressure water does not escape to the primary side. Excessive rising pressure was applied, and the handle operation became very heavy, or the handle operation could not be performed halfway, causing freezing.

[0004]

SUMMARY OF THE INVENTION Therefore, according to the present invention, it is possible to completely remove the defects of the above-mentioned known examples and to perform a simple operation, so that the pressure resistance test can be performed with a test pump from the secondary tap. It is an object of the present invention to provide a backflow-prevention type antifreeze water tap having a valve seat, which can normally operate the handle even with the valve closed.

[0005]

In order to achieve the above object, the present invention provides a water stop cylinder between a valve seat of a valve box and an outlet above the valve seat, and a water stop cylinder having the same diameter as the water stop cylinder above the outlet. A drain cylinder is provided, and at the lower part of the piston where the water-tight annular packing and the drain annular ring are attached in close contact with the cylinder,
A non-return piece for forming a sealing portion at the lower end to prevent backflow by a non-return annular packing, forming a small-diameter portion above the pressure-introducing portion, and closing the valve seat at the lower end on the outer periphery of the small-diameter portion. It is equipped with a packing, and a check valve that is constantly pressed downward by a check spring is connected movably up and down.When performing a pressure test, the handle of the antifreeze water tap is rotated by a fixed angle in the closing direction. Then, the piston is lowered to release the sealing of the sealing portion and the check valve body so that the pressure from the secondary side is released from the pressure introducing portion to the primary side. The same pressure is applied in the opposite direction to suppress an increase in the pressure in the pipe downstream of the outlet.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, basically, at the time of stopping water, a check piece packing is pressed against a valve seat to stop water. At that time, the space between the piston and the sealing portion is not sealed. Although a watertight packing using an O-ring is mounted between the piston and the check valve body, this may be mounted on the check valve body side without mounting the watertight packing on the piston. A piece packing may be used instead of the ring.
Further, it is also possible to use the non-return piece packing only for preventing backflow, and to stop the water with the water-stop ring packing. In that case, the water-stop packing becomes unnecessary.

The pressure introducing portion has a shape in which a part of the cylinder is hollowed out in the vertical direction. This is because the small diameter portion serves as a guide for the check valve body. If a guide is provided separately such as providing several guide walls between the cylinder and the valve seat, the entire pressure introducing section can be made a cylinder having a smaller diameter than the sealing section, and a step is provided inside the piston, A non-return annular packing can be attached to the sealing portion. If a one-way sealing packing such as Y packing is used for the check annular packing, there is no danger that water will not come out due to frictional force even in an area where pressure is low, since there is little sliding resistance. However, depending on the design, it is also possible to use a normal O-ring.

In the embodiment, the connection between the piston and the check valve body is such that the lower end of the small-diameter portion is forcibly expanded outward after the check valve body is inserted after the check valve body is inserted. It does not come off, but this can be done, for example, by screwing a small diameter part having a large diameter step at the lower end to the piston, or by using an O-ring or a metal elastic ring with the end cut off as a retaining member There are various mounting methods, and any method may be used as long as it does not hinder the vertical movement of the check valve and does not separate the check valve from the piston when the piston is pulled out.

[0009]

Embodiments will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a valve box, and an inlet 2 is provided below the side wall.
Above the outlet 3 and further above the drain 4
Is provided. Inside, an upwardly facing valve seat 5 is provided between the inflow port 2 and the outflow port 3 and a water stop cylinder 6 is provided above the valve seat 5. Drain cylinders 7 and 8 having a diameter are provided.

Reference numeral 9 denotes a piston. Drain annular packings 10 and 11 and a waterproof ring packing 12 are mounted on the outer periphery, and a dovetail groove is provided below the waterproof packing 13 so that the waterproof seal 13 is not detached downward. The small diameter portion 14 is formed below it. In the small-diameter portion 14, a pressure introducing portion 15 whose one end is vertically deeply deepened in an intermediate portion, a cylindrical sealing portion 16 below the pressure introducing portion 15,
At the lower end, a retaining portion 17 is provided which is slightly widened outward.

Reference numeral 18 denotes a check valve, which is provided at its upper end with a water stop portion 19.
, A watertight block packing 20 is mounted on the lower end, and a non-return annular packing 21 is mounted inside, and a downward pressing force is constantly received by a non-return spring 22 locked to the piston 9.

The valve box 1 is extended upward by a pipe 23 and connected to and fixed to an operation unit main body (not shown) on the ground, and the piston 9 is extended upward by a rod 24. It is connected to the handle via the rod.

The figure shows a water stop state in which the antifreeze water tap is opened and water is not flowing, but when a faucet (not shown) provided at the end of the downstream pipe of the outlet 3 is opened, the inlet is opened. The water from 2 compresses the check spring 22 and raises the check valve 18 along the small-diameter portion 14 to enter a water-permeable state. When a negative pressure is generated on the main pipe side due to water cutoff or the like from a water stop state or a water discharge state and the pressure on the inflow port 2 side decreases, the check valve element 18 immediately descends due to the restoring force of the check spring 22. The check annular packing 21 is tightly attached to the sealing portion 16 to prevent the water in the pipe on the outlet 3 side from flowing back to the inlet 2 side.

Next, at the time of installation, a handle (not shown) is used when a pressure test is performed from the faucet side to the water stopcock with a test pump.
Is rotated, and the pressure resistance test may be performed in the state of FIG. 2 in which the piston 9 is lowered by a certain distance. That is, while the annular drainage packing 11 is in close contact with the drainage cylinder 7, the watertight annular packing 12 is not yet in close contact with the watertight cylinder 6, and the check annular packing 21 is detached from the sealing portion 16 to the outside of the pressure introducing portion 15. If the gap between the piston 9 and the water stopping cylinder 6 and the inner diameter of the check valve 18 and the sealing portion 16 is appropriately provided, the pressure applied by the test pump from the faucet side is equal to the pressure. Through the introduction section 15, the water reaches the water stopcock as it is.

At this time, the operating rod may be marked in advance and the handle may be visually lowered to that position, or the spacer may be fitted into the operating rod until the spacer comes into contact with the upper end of the operating section body. In this case, the withstand voltage test can be easily performed.

When the drainage state is set, the piston 9 may be further lowered from the state shown in FIG. 2. First, the water-stop annular packing 12 comes into close contact with the water-stop cylinder 6 to shut off water from the inflow port 2. Further, the drainage annular packing 11 separates from the drainage cylinder 7 and water in the outflow side pipe passes through the drainage port 4 and is discharged into the ground. That is, so-called simultaneous water leakage, in which water from the inflow port 2 flows directly to the drain port 4 side, does not occur. Finally, with the check piece packing 20 in close contact with the valve seat 5, the water stop packing 13 contacts the water stop portion 19 of the check valve body 18, and the piston stops descending. That is, in the drained state, the annular ring packing 12 and the check piece packing 2
That is, the water from the inflow port 2 is stopped by 0 and the water stop packing 13.

At this time, since the annular drainage packing 10 is in close contact with the drainage cylinder 8, the water does not rise in the pipe 23.
The drain cylinder 8 and the drain annular packing 10 may be omitted.

If the faucet is closed, that is, if the check piece packing 20 is in close contact with the valve seat 5, and the piston 9 is lowered, the check annular packing 21 is removed until the check ring 21 is detached from the sealing portion 16. Although the compression of water in the downstream piping downstream from the outlet occurs during a short distance, the compressed water escapes from the pressure introducing portion 15 to the inlet 2 side after the separation, and the water stops. Since the cylinder 6 and the drainage cylinder 7 have the same diameter, there is no compression until the drainage annular packing 11 comes off from the drainage cylinder 7 after the watertight annular packing 12 comes into close contact with the watertight cylinder 6, and the handle The operation becomes smooth.

When the piston 9 is pulled out of the pipe 23 due to a packing accident or the like, the check valve 18 is not detached because it is locked by the retaining portion 17.

[0020]

As described above, in the antifreeze water tap according to the present invention, when the pressure resistance test is performed from the faucet to the water stopcock with the test pump at the time of installation, the operation rod is lowered by a predetermined small distance. Only need to pull out the piston and insert a pressure-resistant piston instead.Even if there is no trouble, and even if the faucet is closed and the water is shut off, the pressure rise will be slight. This has the effect that the steering operation can be suppressed and no inconvenience occurs in the operation of the steering wheel.

[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 longitudinal sectional view showing a state of a piston during a pressure resistance test of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 2 Inflow port 3 Outlet port 4 Drain port 5 Valve seat 6 Water stop cylinder 7, 8 Drain cylinder 9 Piston 10, 11 Drain ring packing 12 Water stop ring packing 13 Water stop packing 14 Small diameter part 15 Pressure introduction part 16 Sealing part 17 Retaining part 18 Check valve 19 Water stopping part 20 Check piece packing 21 Check ring packing 22 Check spring 23 Pipe 24 Rod

Claims (1)

[Claims] 1. An inflow port, an outflow port, and a drain port in order from the bottom on the side wall, and an upward valve seat between the inflow port and the outflow port and a water stop cylinder above the inflow port, an outflow port and a drain port. A valve box with a drain cylinder of the same diameter as the cylinder above, and a watertight annular packing and a drainage annular packing that slide on both cylinders are attached, and below the watertight annular packing, check at the lower end. A sealing portion for preventing backflow by an annular packing is connected to a piston forming a small diameter portion provided with a pressure introducing portion above the sealing portion, and the outer periphery of the small diameter portion is vertically movably connected, and the valve seat is closed at a lower end. A non-returnable antifreeze water tap comprising a check valve body fitted with a check piece packing and a check spring engaged with the piston and pressing the check valve downward.