JPH044057Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the valve mechanism of a backflow prevention type anti-freeze faucet that prevents water from flowing backwards from an outlet to an inlet.

Conventionally, a backflow prevention device is attached to the piston of an antifreeze faucet to prevent backflow of water or hot water in the outflow side piping when negative pressure is generated on the main pipe side.
Various types of check valves have been proposed in which the check valve can be easily removed and repaired in the event of an accident with the check valve.

For example, Japanese Utility Model Publication No. 58-42534 by the same applicant makes it possible to remove and repair the check valve by installing a check valve with a non-return gasket on the outside of the piston. It is now possible to provide an anti-freeze faucet that can provide a larger flow rate than when it is housed inside a piston.

However, the above-mentioned piston has two joints in order to install a check valve on the outside of the piston, and also has a communication hole inside that extends from the lower end to above the top ring-shaped packing. , it is necessary to seal the threaded part of the two joints, but since the outside diameter of the piston is limited, it is difficult to seal the seal, and in reality, adhesive is applied, but there was an accident with the check valve. In such cases, it is difficult to disassemble and the adhesive must be reapplied when reassembling.

The present invention was proposed to eliminate the above-mentioned defects, and although the pistons are made into two joints, the communication hole inside the piston is omitted, and sealing with the threaded part is no longer necessary. Therefore, when the piston moves up and down, the lower end chamber of the piston tends to become a negative pressure. In this invention, we make use of the above properties to make the sealing effect of the drain valve connected to the drain port more complete, and also provide a drain port above the inlet port, so that in case water leaks into the pipe, The water is drained underground.

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

In the figure, 1 is the valve box of the antifreeze faucet of the present invention, and the side wall has an upper drain port 2, an inlet port 3, an inlet port 3,
An outflow port 4 and a lower drain port 5 are provided. Inside, a cylinder 6 is provided between the inlet 3 and the upper drain port 2, a cylinder 7 is provided between the inlet 3 and the outlet 4, and a cylinder 8 is provided between the outlet 4 and the lower drain 5. Note that the cylinders 6, 7, and 8 are each formed to have the same diameter. The piston 9 is a two-piece joint, and the upper piston 9' is equipped with two annular gaskets 10 and 11 that slide on the cylinders 6 and 7, and the lower piston 9'' is equipped with an annular gasket 12 that slides on the cylinder 8.
Attach. Narrow diameter section 1 above the lower piston 9''
3 is formed, and a gap is provided between the cylinder 7 and a conduction path 14 which becomes a water flow path. Narrow diameter part 1
3 is equipped with a check valve 17, which is equipped with an outer check gasket 15 that slides on the cylinder 7 on the outside, and an inner check gasket 16 that slides on the narrow diameter portion 13 on the inside, and is always held by a spring 18. Insert it so that it can move up and down so that an upward force is applied. Backstop packing 1
For 5 and 16, one-way sealing gaskets with a Y-shaped cross section are used to block only the flow of water from the outflow port 4 side to the inflow port 3 side, which reduces frictional resistance. Although there is an advantage that a large flow rate can be obtained even at low pressure, the present invention is not necessarily limited to this, and a normal O-ring can also be used. A discharge valve 20 for preventing sewage from entering from underground is connected to a lower discharge port 5 adjacent to the piston lower end chamber 19 and an upper discharge port 2 provided above the cylinder 6. The drain valve 20 uses an O-ring 22 on the valve seat that the ball valve 21 contacts,
It is designed to improve the sealing effect. Although not shown, the valve body 1 is extended upwardly by a pipe 23, and the piston 9 is extended upwardly by a rod 24, and connected to an upper support fitting and a handle. Further, the inlet 3 is connected to a water supply pipe, and the outlet 4 is connected to a riser pipe.

Next, the operating mode of the present invention will be explained.

The figure shows a state where the antifreeze faucet is open and the faucet at the end of the pipe is closed, that is, the water is stopped. When the faucet is opened from this state and water is flowing, water from the inlet 3 flows out. flows into the conduction path 14,
While compressing the spring 18, the non-return valve 17 is pushed down, causing the flow to separate from the cylinder 7, flow to the outlet 4, and flow out of the faucet through the riser pipe. In this state, the annular packing 10 is in close contact with the cylinder 6, and the annular packing 12 is in close contact with the cylinder 8, and there is no leakage to other places.

When the faucet is closed or negative pressure is generated on the main pipe side, the restoring force of the spring 18 causes the check valve 17 to rise instantaneously, and the outside check valve 15
is in close contact with the cylinder 7, and the inner non-return gasket 16 is in close contact with the narrow diameter portion 13, so even if negative pressure is generated on the main pipe side due to water cutoff construction etc., water or hot water will not flow from the outflow port 3 to the inflow port 2 side. Backflow can be completely prevented.

Next, when you want to drain the water in the riser pipe, it is best to lower the piston 9 by operating the handle. First, the annular packing 11 comes into close contact with the cylinder 7, and the annular packing 10 blocks water from the outlet 3. Thereafter, the annular packing 12 is separated from the cylinder 8, and the water in the riser pipe is discharged from the outlet 4 to the cylinder 8.
The piston lower end chamber 1 passes through the gap between the small diameter portion 13 and the
9, pushes up the ball valve 21 through the drainage port 5, and is discharged into the ground. After draining, the ball valve 21 is in close contact with the O-ring 22 to prevent dirty water from entering the piston lower end chamber 19, but in the present invention, the piston 9
When the piston rises, the piston lower end chamber 1
9 is about to become negative pressure, the ball valve 21 is
It adheres even more strongly to the ring 22, making the seal perfect. Therefore, there is an advantage that there is no risk of dirty water entering the valve box from the outside during the open state, which is overwhelmingly long in terms of time. If water rises in the pipe 23 and freezes, it will be impossible to operate the handle, but in the present invention, the water rising in the pipe 23 is also drained underground from the upper drain valve 20. There is no such danger as the water will be drained away. In this case, the annular packing 1
0 is always cylinder 6 in both open and closed states.
Because it is in close contact with the
Therefore, the upper drain valve may be omitted and only the drain port 2 is provided, and
The drain port 2 is provided with a pipe 23 instead of the valve box 1.
Alternatively, it may be provided at the threaded connection between the valve box 1 and the pipe 23.

As mentioned above, in this invention, since there is no communication hole inside the piston, the piston itself
and the cylinder can be made that thinner,
There is no need to consider sealing at two joints,
Disassembly and assembly are easier, and the risk of underground sewage entering the valve box and contaminating drinking water is also reduced.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing an embodiment of the present invention. 1 is a valve box, 2 is an upper drain port, 3 is an inlet, 4 is an outlet, 5 is a lower drain port, 6, 7, 8 are cylinders, 9 is a piston, 10, 11, 12 are annular packings, 13 is a The small diameter part, 15 is an outer non-return packing, 16 is an inner non-return packing, 17 is a non-return valve, 18 is a spring, 20 is a drain valve, 21 is a ball valve, 22 is an O-ring, and 23 is a pipe.

Claims (1)

[Scope of utility model registration request] A piston fitted with a required number of annular gaskets moves up and down inside a cylindrical valve box that has an inlet, an outlet, and a drain on the side wall, and a pipe is connected to the upper end to shut off water and drain water. In freezing water faucets,
In the above valve box, a drain valve using an O-ring is connected to the valve seat where the ball valve comes into contact with the lower drain port provided below the outflow port, and an upper drain port is also provided on the side wall of the valve box or pipe above the inflow port. In addition, the piston has at least two joints, and has a narrow part between the annular packings for blocking the inlet and the outlet, and the outlet and the drain, and an inner non-return packing that closely contacts the narrow part; A backflow prevention type characterized by a backflow prevention valve equipped with an outer non-return gasket that tightly contacts the cylinder between the inflow and outflow ports, held upward by a spring, and fitted into the narrow part so as to be able to move up and down. Valve mechanism of antifreeze faucet.