JPH027983Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a drain valve having a backflow prevention mechanism.

(b) Conventional technology In cold regions such as Hokkaido, water pipes are buried underground below the freezing depth. This is because no matter how much the temperature on the ground drops, water will not freeze underground below the freezing depth. However, the branch pipes connected to the water pipes are led to each house, and if the tap water is left unused for a certain period of time, the water in the branch pipes of each house may freeze. Therefore, when people were out for long periods of time during the day or when they went to bed, there was a need to release the water between the branches into the ground, and a drain plug was devised. As shown in FIG. 1, the drain valve 1 has a water pipe attachment part 3 attached to the water pipe 2, a branch pipe attachment part 4, a drainage part 5, and a branch pipe 6.
One end is connected to the branch pipe attachment part 4, and the other end is connected to the faucet 7.
It follows. Normally, tap water is used by opening and closing the faucet 7, but when going to bed, the handle 8 of the drain valve is operated to discharge the water in the branch pipe 6 from the drainage part 5 into the ground. If you are connecting a hose 9 to a faucet 7 and connecting it directly to an electric washing machine or washbasin 10 to supply water, if there is a sudden water outage due to water main construction, etc., negative pressure will occur in the main pipe, causing the washing machine to shut off. The dirty water in the washbasin may flow back into the water pipe 2 through the hose 9, the faucet 7, and the branch pipe 6. Furthermore, in apartment complexes, it is increasingly common for each room to have a water drain valve in addition to the main water drain valve. Various drain plugs have been devised to prevent this.

(c) Problems to be solved by the invention In the conventional drain valve with a backflow prevention mechanism, the small diameter part of the piston, etc.
112991) is equipped with a non-return valve, and the small diameter part of the piston is moved by opening and closing the faucet installed on the outflow (secondary) side. However, because this happens many times, the gasket attached to the check valve wears out, leading to unexpected accidents.
Except for the above-mentioned drawbacks, this invention does not include a check valve, and the valve piece moves only when negative pressure is generated on the inflow (primary) side to prevent back flow.

(d) Means for solving the problem In the figure, 11 is the outer tube, and 12 is the external body.
The spindle 13 has a handle 8 attached to its upper part, and an intermediate shaft 14 attached to its lower part.
Attach the piston 15 to the lower part of the piston 15.
A rod 16 is fitted into the inside of the valve, and a valve piece 17 is screwed into the lower part of the rod 16. A square internal thread is cut inside the upper body 12 and is screwed into a square thread 18 provided at the center of the spindle 13. Therefore, when the handle 8 is turned, the square screw 18 moves up and down, and the piston 1
5. The rotor 16 and the valve piece 17 also move up and down. The middle shift 14 may be quite long depending on the depth of freezing, and the length of the middle shaft 14 is also long when drain valves are provided on the second or third floor. 19, 20, 21,
22 are all Patsukin. FIG. 2 shows the position when water is supplied. Water from the water pipe 2 is led to the branch pipe 6 via the branch pipe attachment part 4, and does not flow out to the drain part 5. To shut off the water at night when sleeping, operate the handle 8 to raise the piston 15, rod 16, and valve piece 17 to the state shown in FIG. 3. The water from the water pipe 2 is closed, and the water in the branch pipe 6 passes through the branch pipe attachment part 4 and is discharged from the drainage part 5 into the ground below the freezing depth. Note that the spring pin 31 30 is an idling shaft. The above is a description of publicly known products. The novel points of the present invention are as follows. 23 is a spring, and 24 is a C-shaped retaining ring.

(E) Function When water is supplied, as shown in FIG. 2, since the water pressure is stronger than the force of the spring 23, the upper protrusion 25 of the rod 16 is lowered until it touches the end surface 26 of the piston 15, and does not interfere with the water supply. If there is a water outage during the water supply and negative pressure occurs, the water pressure will no longer work.
The rod 16 and the valve piece 17 rise due to the action of the spring 23, and the upper end surface 27 of the rod 16 touches the C-shaped retaining ring 2.
Close to 4. At this time, as shown in Figure 3, Benkoma 17
Since the gaskets 21 and 22 which are encircled in the cylinders 28 and 29 are in contact with the cylinders 28 and 29, backflow is prevented.
When the water is stopped, as shown in Fig. 4, the packing 22 is separated from the cylinder 29 and the packing 21 is in contact with the cylinder 28, so that the branch pipe 6
The water inside can be drained through the drain valve 5. In addition, the spring 23 may be omitted and the valve piece 17 made of a material with low specific gravity, the number of gaskets may be changed, the water pipe attachment portion 3 and the branch pipe attachment portion 4 may be reversed, or the piston 15 and rod 16 valve pieces may be replaced. You are free to make design changes without departing from the gist of the present invention, such as changing the connection method of 17 as appropriate.

(f) Effects of the device This device has the above structure and operates as described above, so it is effective in preventing backflow even if there is a sudden water cutoff.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a drain valve. FIG. 2 is a front sectional view of the product of the present invention, showing the state when water is being supplied. Third
The figure is a partially cutaway front sectional view of the product of the present invention, and shows the state under negative pressure. FIG. 4 is a partially cutaway front sectional view of the product of the present invention, showing the state when water is stopped.

Claims (1)

[Scope of utility model registration request] A piston 15 is constructed of an upper body 12, an outer shell pipe 11, and has a water pipe attachment part 3, a branch pipe attachment part 4, and a drainage part 5. Loosely fit the rod 16 inside the
The lower part of the rod 16 and the valve piece 17 are screwed together, the spring 23 is housed inside the piston 15, and the piston 15 and the valve piece 17 are fitted with gaskets 19, 20, 2.
A drain valve with a backflow prevention mechanism, which is equipped with 1 and 22.