JPH0234257Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a drain valve having a backflow prevention mechanism and a pressure reduction 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, it became necessary to release the water in the branch pipes into the ground, and a drain plug was devised. As shown in FIG. 1, the drain valve 1 has an inflow part 3, an outflow part 4, and a drainage part 5, which are attached to the water pipe 2. One end of the branch pipe 6 is connected to the outflow part 4, and the other end is connected to the faucet 7. Connected. 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.

When connecting the hose 9 to the faucet 7 and directly connecting it to an electric washing machine or washbasin 10 to supply water,
When water mains are suddenly cut off due to construction work, etc., negative pressure is generated in the main pipes, and sewage in the washing machine or washbasin may flow back into the water pipes 2 via the hose 9, the faucet 7, and the branch pipe 6. In addition, in apartment buildings, it is increasingly common for each room to have a drain valve in addition to the main water drain valve, but if the above-mentioned backflow occurs, there is a risk that sewage will be sent throughout the apartment building, so backflow is prevented. Various devices have been devised to prevent this. Also, especially in areas with high water pressure, when closing the faucet,
Abnormal noise caused by water hammer,
In order to avoid accidents such as damage to meters and pipe fittings, or because it is uneconomical to use a large amount of water just by opening the faucet a little, install a pressure reducing valve or throttle valve in the middle of the pipe from the drain valve to the faucet to lower the water pressure. , often restricting the flow rate.

(c) Problems that the invention aims to solve As mentioned above, if devices to prevent backflow or reduce pressure are installed, in cold regions the water in the pipes will not drain completely and will freeze, causing the pipes and equipment to become damaged. It has the disadvantage that it can break and lead to unexpected accidents, that the piping must be complicated to prevent such accidents, and that it is cumbersome to operate. In view of the above points, an object of the present invention is to provide a drain valve having a backflow prevention mechanism and a pressure reduction mechanism. (d) Means for solving the problems In FIG. There are a drain port 12, an inflow section 3, and an outflow section 4 from top to bottom, and three cylinders 13, 14, 15 inside from top to bottom.
make a profit. The piston 16 has three O-rings 17, 18, 19 on the outside and a gasket 20 on the inside.
is installed, the outer diameter between O-rings 18 and 19 is slightly smaller, and a horizontal hole 21 is drilled in that part.
A flange portion 22 is provided at the center of the interior. The rod 23 is equipped with a packing 24 on the outside of the upper part and a retaining ring 25 made of elastic resin on the outside of the lower part, a vertical hole 27 communicating with the horizontal hole 26 is bored inside, and a protrusion on the upper part. 28, and a valve piece 30 is loosely fitted into the center of the rod 23 and is constantly given a lifting force by a spring 29.
There is an O-ring 31 on the outside and a packing 3 on the inside.
2,33 are installed. Further, the rod 23 is constantly given a downward force by a spring 34. Therefore, when the water starts flowing and when the water stops, the lot 23
While a downward force is always applied to the rod 23 by the spring 34, a force obtained by multiplying the cross-sectional area of the rod 23 by the pressure of the outflow portion 4 always acts on the rod 23 as an upward force.

(E) Action Figure 2 shows the situation when the drain valve is in the water supply state and the faucet is open. At this time, the valve piece 30 is pushed down by the flow of water and its lower end is in contact with the retaining ring 25 , and the rod 23 is moved by the action of the spring 34 until the upper protrusion 28 comes into contact with the flange 22 inside the piston 16 . It's descending. In this state, when negative pressure is generated on the primary side due to main pipe construction, etc., a lifting force is applied to the valve piece 30 due to the action of the spring 29, and the valve piece 30 rises as shown in FIG.
1 is in contact with the cylinder 15, and the gaskets 32, 33
Since it is in contact with the rod 23, backflow is prevented. On the other hand, when the faucet is gradually closed in the state shown in Fig. 2, the secondary water pressure increases, which increases the upward force pushing up the rod 23, causing the rod 23 to rise while compressing the spring 34. However, the flow rate decreases. When the faucet is finally completely closed, that is, when the water is stopped, the secondary water pressure reaches its maximum, and the 4th
As shown in the figure, the rod 23 rises until its upper end contacts the lower end of the spring receiver 35, and the O-ring 31
is in contact with the cylinder 15, and the gaskets 32, 33 are in contact with the rod 23, so the inflow portion 3 and the outflow portion 4 are blocked. The strength of the spring 34 may be set so that the secondary water pressure at this time becomes the set water pressure. Therefore, if a strong spring is used, the set secondary pressure will increase, and if a weak spring is used, the set secondary pressure will decrease.

Also, in the state shown in Figure 2, move the handle 8 to the spindle 3.
6 is rotated so that it rises, the shaft suspension 37, middle shaft 38, and idle shaft 39 rise, and accordingly, the piston 16 connected to the idle shaft 39 by a spring pin 40 also rises, as shown in FIG. becomes drained. At this time, the O-rings 17 and 19 are in contact with the cylinders 13 and 14, the O-ring 31 is in contact with the cylinder 15, and the seals 20, 24, 32, 3
3 are in contact with the piston 16 and the rod 23, respectively, so there is no flow of water from the inflow to the outflow direction, and the secondary water flows through the vertical hole 27, the horizontal hole 26, and the rod 23 of the rod 23.
The drain port 12 and the drain section 5 pass through the horizontal hole 21 of the piston.
through which the water is drained to the outside.

(f) Effects of the invention Since the invention has the above structure and operates as described above, it prevents backflow even in the event of a sudden water outage, and can maintain the tap water pressure below the set pressure in areas with high pressure. have an effect.

[Brief explanation of the drawing]

Figure 1 shows a simple example of piping including 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 and the faucet is open. FIG. 3 is a partially cutaway front sectional view of the product of the present invention, showing a state in which water is supplied and negative pressure is applied. FIG. 4 is a partially cutaway front sectional view of the product of the present invention, showing the state when the faucet is closed while water is being supplied. FIG. 5 is a front sectional view showing a part of the product of the present invention with a cutaway,
This shows the condition when draining water.

Claims (1)

[Scope of utility model registration request] The spindle 36, the middle shaft suspension 37, and the middle shaft 38, which are moved up and down by the operation of the handle 8, are housed inside the upper body 42 which is screwed into the outer tube 41, and the cylindrical lower body 11 which is screwed into the outer tube 41 is housed. There are drain ports 1 on the side from top to bottom.
2. It has an inflow part 3 and an outflow part 4, and inside there are three cylinders 13, 14, 15 in order from the top,
Piston 1 enclosing O-rings 17, 18, 19
6 is fitted with a rod 23 which is constantly given a downward force by a spring 34, and in the center of the rod 23 is a valve which is always given a rising force by a spring 29, and an O-ring 31 is mounted on the outside. Piece 30 is installed, and in fact, piston 16,
This is a pressure-reducing drain valve with a backflow prevention mechanism, which combines the rod 23 and the valve piece 30 into one and accommodates it in the upper body 11.