JPH0429166Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a check valve. In particular, check valves are provided on the inlet and outlet sides of the main body, arranged on the same axis, and both check valves are arranged on the same axis. A relief valve is provided in the middle to introduce fluid pressure on the inlet side and close the valve, so that when one or both of the check valves fails and becomes in a communication state, the relief valve absorbs the fluid pressure on the inlet side. Open against the
This invention relates to a check valve that discharges water in a central chamber to the atmosphere and prevents water on the outlet side from entering a supply source on the inlet side.

[Prior Art] As a conventional check valve of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 56-86287 as shown in FIGS. 2 to 5. It consists of a body 10 with an inlet 12 and an outlet 14 and a lid 16, and the interior of the body 10 is divided into an inlet chamber 28, a central chamber 30, and an outlet chamber 32. The inlet chamber 28 is connected to the central chamber 3 by a primary check valve mechanism 34.
0, and the central chamber 30 has a secondary check valve mechanism 36.
It is separated from the exit chamber 32 by. The inlet chamber 28, central chamber 30, and outlet chamber 32 are arranged in a line on the same axis, and when the primary check valve mechanism 34 and the secondary check valve mechanism 36 are opened, water flows from the inlet 12 to the outlet 1.
4 flows. The valve seat 38 of the primary check valve mechanism 34 is attached to the main body 10 and has a valve guide 60 in the center. A valve rod 62 fixed to a valve element 72 is inserted into the valve guide 60, and the valve rod 62 presses the valve element 70 against the valve seat 38 by a pressing spring 78 that is engaged with the valve guide 60. Similarly, in the secondary check valve mechanism 36, the valve body 73 presses the valve seat 39 with a spring 79. In addition, the holes 84, 86, and 88 are for connecting pressure gauges to the inlet chamber 28, central chamber 30, and outlet chamber 32.
You can visually check the pressure.

FIG. 4 is a cross-sectional view of the central portion of FIG. 2, in which a relief valve mechanism 90 is provided at a right angle to the central chamber 30 and controls the flow to the outlet 92. and central chamber 30
The relief valve mechanism 90 has a hole 94, a chamber 96 or a chamber 98,
It is communicated by a hole 112. The relief valve mechanism 90 consists of valves 102, 104 and a valve stem 106, and the valves 102, 104 move coaxially and integrally.
When the valve stem 106 is lowered, the valve 102 is pressed against the valve seat 110 and the valve 104 closes the hole 112. The valve stem 106 is then fixed to the membrane 124 at the top, and the membrane 124 is fixed at the top.
24 separates chamber 96 and chamber 128. Room 128
communicates with the inlet chamber 28 by a hole 130 in the body 10, as shown in FIG. Chamber 96 communicates with central chamber 30 by hole 94 . Room 128 and Room 96
The force generated by the pressure difference between the relief valve mechanism 90 and the spring 120 is stronger than the force of the spring 120 provided in the relief valve mechanism 90.
02 and the valve 104 are closed, and the discharge port 9 is opened.
It does not flow to 2, but ensures that it does not flow backwards from the outlet side to the inlet side. However, when the primary check valve mechanism 34 or the secondary check valve mechanism 36 becomes unable to close due to foreign matter being trapped, the inlet chamber 2
8 and the central chamber 30, i.e. chamber 128
When the pressure difference between the
02 to open the relief valve mechanism 90. When the relief valve mechanism 90 is opened, water is discharged to the outlet 92 side rather than flowing to the inlet 12 side, thereby preventing contamination of the water source.

[Problems to be solved by the invention] The conventional check valve described above has a pressure P1 in the inlet chamber 28, a pressure P2 in the central chamber 30, and a pressure P in the outlet chamber 32.
3 is set so that the push springs 78 and 79 provided in the check valve mechanisms 34 and 36, respectively, satisfy the relationship P1>P2>P3. Therefore, from inlet 12 to outlet 1
In order to flow from P1 to P3, the fluid pressure is consumed and lowered from P1 to P3 against the pressure of two presser springs 78 and 79.
For this reason, the pressure on the water supply side needs to be a certain higher pressure than the pressure on the usage side. Furthermore, since the valve bodies 72 and 73 of each check valve mechanism are provided individually, they are likely to be twisted or rotated, resulting in wear and tear of the valve mechanism and frequent occurrence of failures. Furthermore, the opening and closing of the relief valve mechanism 90 is based on the pressure difference P1-P2 between the inlet chamber 28 and the central chamber 30.
The check valve mechanism 36 opens when the water in the central chamber 30 is opened to prevent the water from the outlet 14 from flowing back to the inlet 12, thereby preventing the secondary check valve mechanism 36 from getting caught in foreign matter. If the seal of the primary check valve mechanism 34 is broken due to a breakdown due to blockage, etc., the above P1-P2 will decrease and the water on the inlet side 12 will always pass through the relief valve mechanism 90 and be discharged to the outlet 14 side. There is a problem in that the clean water from the inlet 12 side is discharged instead of the dirty water.

[Means for Solving the Problems] The gist of the present invention is to arrange an inlet chamber, a central chamber, and an outlet chamber on an axis in a valve box, and to provide a primary check valve between the inlet chamber and the central chamber. In the check valve, a secondary check valve is provided between the central chamber and the outlet chamber, and the central chamber is configured to allow fluid to escape to the relief chamber via a relief valve. A valve stem is connected to the valve body of the valve body, and the valve stem is engaged with a first spring fixed in the valve box to bias the valve body toward the valve seat of the temporary side check valve, and A connecting rod is connected to the body, and the connecting rod has a stepped portion and is inserted into the valve body of the secondary check valve.
A second spring is locked to the inserted end and engaged with the valve body of the secondary check valve, thereby biasing the valve body toward the valve seat side of the secondary check valve. This is a check valve that is characterized by:

[Operation] Since the present invention has the above configuration, when the primary valve body opens against the first spring blocking the primary check valve, the valve body of the secondary check valve simultaneously opens. As the connecting rod inserted into the valve also moves, the pressing force of the second spring that closes the secondary check valve is reduced, causing the secondary valve element to follow the primary valve element. open. In other words, assuming that the pressure in the inlet chamber is P1, the pressure in the central chamber is P2, and the pressure in the outlet chamber is P3, in normal flow conditions, a constant pressure difference is created between P1 and P2 by the first spring as in the past. However, since the force of the second spring pressing the valve body of the secondary check valve at P2 and P3 has decreased, the water in the central chamber flows to the outlet chamber with almost no pressure difference. Flowing. Therefore, pressure loss is small, and since each valve body is connected, rotation and twisting are less likely to occur. Additionally, since the connecting rod has a step, when the primary side valve element opens, the secondary side valve element is also pushed open, so there is a possibility that the secondary side check valve's valve element may fail and remain closed. does not continue to drain water from the traditional supply side.

[Example] An example of the present invention will be described below with reference to FIG. The primary side check valve 34 has a valve body 72 and a valve stem 62 fixed as in the conventional case, and the valve stem 62 is inserted into a valve guide 60 that is integrated with a valve seat 38 attached to the main body 10. locks the first spring 78 and presses the valve rod 62 toward the inlet 12, that is, the valve body 72 toward the valve seat 38. The first spring 78 is strong enough to create a constant pressure difference between the inlet chamber 28 and the central chamber 30. A connecting rod 9 is connected to the valve body 72 side of the valve rod 62, and the connecting rod 9 is connected to the secondary side check valve 3.
6 into the valve body 73 of the secondary check valve 36 , a retaining ring 64 is locked to the inserted end, a second spring 79 is attached, and the valve body 73 of the secondary side check valve 36 is pressed against the valve seat 39 . are doing.

In addition, a stepped portion 91 is formed in the portion of the connecting rod 9 that is inserted into the valve body 73, and when the valve body 72 of the primary side check valve 34 is opened, the secondary valve is formed at the stepped portion 91 of the connecting rod 9. The valve body 73 of the side check valve 36 is pushed open.

The parts other than those described above have the same structure as in FIGS. 2, 3, and 5 described in the conventional example, and a relief valve 90 is provided through a hole 94 in the central chamber 30.

[Effects] As described above, in the non-return valve of the present invention, in normal flow conditions, the secondary check valve opens almost following the primary check valve, so the pressure difference is reduced and the pressure loss is reduced. Less check valves can be obtained. Further, since the primary check valve and the secondary check valve are opened almost in conjunction with each other, it is possible to prevent the secondary check valve from malfunctioning and remaining in a closed state. Furthermore, since the valve bodies on the primary and secondary sides are connected, the valve bodies do not rotate or twist, and long-term sealing performance can be ensured.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of an embodiment of the present invention, Figs. 2 to 5 show a conventional example, Fig. 2 is a plan view thereof, and Fig. 3 is a sectional view taken along line A-A in Fig. 2; 4 is a sectional view taken along line BB in FIG. 2, and FIG. 5 is a sectional view taken along line CC in FIG. 10...Main body, 9...Connection rod, 34...Primary side check valve, 36...Secondary side check valve, 72, 73...
Valve body, 38, 39... Valve seat, 78... First spring, 79... Second spring, 28... Inlet chamber, 30
...Central chamber, 32...Exit chamber, 90...Relief valve.

Claims (1)

[Scope of utility model registration request] An inlet chamber, a central chamber, and an outlet chamber are arranged on the axis in the valve box, a primary check valve is provided between the inlet chamber and the central chamber, and a secondary check valve is provided between the central chamber and the outlet chamber. In the check valve, the valve stem is connected to the valve body of the primary side check valve, and the valve stem is connected to the valve body. A connecting rod is connected to the valve element, and the connecting rod is provided with a stepped portion. The secondary check valve is inserted into the valve body of the secondary check valve, and a second spring is engaged with the inserted end of the secondary check valve to engage the valve body of the secondary check valve. A backflow prevention valve characterized by being biased toward the valve seat side of the stop valve.