JPH067235Y2 - Check valve for water supply - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a check valve for water supply, which is installed in the middle of a water supply pipe and prevents the contaminated water from entering the main pipe side due to negative pressure.

As shown in FIG. 1, generally, a check valve A for water supply is connected to a lead-in pipe B branched from a mains for water supply buried in the ground through a water stop C and a meter D, in cold regions. If so, it is piped into the house by the rising pipe F via the downstream antifreeze water tap E. However, the conventional check valve has a large loss resistance because it is always pressed against the valve opening by the spring, and in particular in a cold region, it is also a major cause of the decrease in water pressure in combination with the loss of the antifreeze water tap E. . Further, when all the end valves provided in the pipeline are closed, the valve body of the check valve is pressed against the valve opening by the spring, so if air is trapped on the secondary side of the check valve. The pressure fluctuation on the primary side, for example, a rapid pressure rise caused by a water hammer compresses the air reservoir on the secondary side of the check valve, thereby increasing the pressure. The increased pressure is not escaped to the main pipe side by the check valve and is retained in the secondary side pipe as it is.Therefore, when the scallop is opened, the water bursts out momentarily and there is a concern that the high pressure may damage the equipment. Was there.

The present invention has been devised to solve the above-mentioned problems, and the gist thereof is that the valve of the valve body is closed so that the valve opening between the inlet and the outlet is closed only when the pressure in the pipe decreases. A check valve for water supply, comprising an air chamber sealed at an end opposite to a mouth, and moving a valve body in a closing direction by a compressed gas in the air chamber and a biasing force of a spring.

That is, when pressure is applied to the inside of the pipe, the compressed air in the air chamber is compressed, and the valve body separates from the valve seat or cylinder regardless of the flow in the pipe to open the valve port. However, once the inside of the pipe becomes a negative pressure, the packing attached to one end of the valve body closes the valve port by the expansion of the compressed gas in the other end chamber and the biasing force of the spring, and stops the reverse flow. As described above, the check valve of the present invention always opens the valve so that it does not become a fluid resistance when pressure is applied in the pipe, and only when the check valve is backflow due to negative pressure. The function is demonstrated. Also, the pressure fluctuation generated on the primary side of the check valve is not retained on the secondary side, so there is no momentary sudden water spouting when the calan is opened, and damage to equipment due to high pressure can be prevented. It is a thing.

Referring next to the embodiment shown in the drawings, FIG. 2 shows an embodiment of a conventional check valve, which is a valve box 4 having an inflow port 1, a valve port 2, and an outflow port 3 in a flow path. The valve body 6 pressed by the spring 5 is seated on the valve opening 2 via the packing 7. One end of the spring 5 is locked in the recess of the valve lid 8 of the valve body 6, and the valve lid 8 is screwed and connected to the valve box 4.

Explaining the operation mode, in the pipe in which the check valve shown in FIG. 1 is installed, when the curran or the like attached at the end is opened, the water in the pipe moves due to the pressure difference and is discharged from the curran. The water flowing in from the inflow port 1 separates the valve body 6 urged by the spring 5 from the valve opening 2 and flows to the outflow port 3. When the curran is closed, the pressure difference disappears and the water flow stops. At this time, the valve body 6 equipped with the packing 7 is seated on the valve opening 2 by the spring 5, and therefore does not flow back even if the pressure on the primary side of the check valve becomes negative. However, in the case where air is trapped on the secondary side of the check valve, if the pressure fluctuation on the primary side, especially a rapid pressure rise due to a water hammer occurs, the valve body 6 is disengaged from the valve opening 2 and the secondary side Compresses the air pocket and raises the pressure. The increased pressure tries to return to the primary side, but at that time, the valve body 6 equipped with the packing 7 is seated at the valve opening 2 and the backflow prevention works, so that it cannot return and the pressure on the secondary side increases. It is kept as it is. As a result, the equipment provided on the secondary side was damaged and suddenly pressured water was ejected when the scallop was opened.

FIG. 3 shows an embodiment in which the present invention is implemented, and the same members as those in FIG. 1 are indicated by the same reference numerals. FIG. 3 shows a valve box 4 having an inflow port 1, a cylindrical valve port 2, and an outflow port 3 as flow paths.
The valve lid 8 is screw-connected to. The valve body 6 has a valve opening 2 at the lower end.
A packing 7 for closing the valve is attached, and a flange portion 15 having a diameter larger than that of the valve port 2 is provided above the packing 7. A rubber ring 9 for sealing is attached to the upper end portion so that a cylinder 11 provided inside the valve lid 8 can slide. Cylinder 1
1 may be provided in the valve box 1 itself. An air chamber 10 is formed between the valve lid 8 and the valve body 6, and a spring 5 that gives a downward force to the valve body 6 is accommodated therein.

The operation mode of the embodiment shown in FIG. 3 is that the air in the air chamber 10 is compressed by the upward water pressure acting on the sealing rubber ring 9 regardless of the fact that the water in the pipe does not move when pressure is applied to the pipe. The valve body 6 is always separated from the valve opening 2. Therefore, the fluid resistance when water flows in the pipe is small, and when the pressure in the pipe becomes negative, the gas in the air chamber 10 expands, and the restoring force of the spring 5 pushes the valve body 6 toward the valve port 2 direction. The valve opening 2 is closed to prevent backflow.

As described above, in the water check valve of the present invention, the conventional valve shown in FIG. 2 has a valve body upper chamber in which water enters and continuously moves up and down due to the flow of water. Water does not enter the air chamber 10 due to the function of the ring 9, and therefore the open state is always maintained when pressure is being applied to the inside of the pipe, and only when the inside of the pipe becomes a negative pressure and a backflow occurs, a backflow function. Is designed to work. Therefore, as described above, the secondary side of the check valve does not maintain a rapid pressure rise due to the water hammer that occurs on the primary side, but protects the equipment and provides a momentary high-pressure jet of water when the calan is opened. It is possible to provide a backflow check valve for water supply which can be prevented and has a small fluid resistance.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of installation and installation of a check valve for water supply, and FIG. 2 is a vertical cross-sectional view of a conventional check valve.
The figures respectively show vertical cross sections of check valves for water supply according to the present invention. In the figure, 1 is an inflow port, 2 is a valve port, 3 is an outflow port, 4 is a valve box,
Reference numeral 5 is a spring, 6 is a valve element, 7 is packing, 8 is a valve lid, 9 is a rubber ring for sealing, 10 is an air chamber, and 11 is a cylinder.

Claims (1)

[Scope of utility model registration request] 1. A valve lid is connected to an upper end of a valve box provided with a valve port between an inflow port and an outflow port, a packing for closing the valve port is attached to one end of the valve box, and the other end of the packing is attached to the other end. The air chamber is formed between the valve body and the valve lid by accommodating a valve body equipped with a rubber ring for sealing that slides on a cylinder formed on either the valve box or the valve lid. A spring that gives a downward force to the valve body is housed in the valve body, and the valve body maintains a fully opened state when pressure is applied to the inside of the pipe, and when negative pressure is generated, the valve opening is closed by the compressed air in the air chamber and the spring. Check valve for water supply.