JP2757212B2 - Emergency shut-off valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency shutoff valve that shuts off a pipeline when a flow rate abnormally increases.

[Conventional technology]

Conventionally, when the flow rate on the downstream side is abnormally increased due to damage to piping such as water supply, the increase is sensed by a flow meter or the like, and the main valve including a butterfly valve is closed to cope with the problem. The opening and closing of the main cock is generally performed by mechanically operating a valve body of the main cock with other driving means such as an electric motor, an electromagnet, and a spring.

[Problems to be solved by the invention]

However, in the case where the valve body is closed by a mechanical operation and the emergency shutoff is performed, there is a case where a reliable shutoff cannot be performed due to a variation in operation due to mechanical friction.

Therefore, an object of the present invention is to provide an emergency shut-off valve that can reliably close a valve body without power and without power by the pressure of liquid flowing through a pipeline without mechanical operation.

[Means for solving the problem]

In order to achieve the above object, the emergency shut-off valve of the present invention
A main valve body for opening and closing the valve port of the main valve, a pressure chamber into which fluid on the primary side of the main valve is introduced via a primary-side pilot pipe, and a fluid in the pressure chamber to the secondary side of the main valve. A secondary-side pilot pipe to be led out, and the fluid in the pressure chamber is led out to the secondary side of the main valve via the secondary-side pilot pipe to change the pressure in the pressure chamber, so that the main valve body is An emergency shutoff valve that opens and closes, and is provided with an orifice on the primary side of the main valve, and is opened when the differential pressure across the orifice rises to allow the primary side fluid to pass therethrough. And a shut-off pilot valve for closing the secondary pilot pipe by closing with the pressure of the fluid passing through the differential pressure pilot valve.

(Operation)

With the above configuration, when the flow rate of the fluid in the pipeline increases abnormally and the pressure difference before and after the orifice increases, the differential pressure pilot valve opens to introduce the fluid on the primary side to the shutoff pilot valve. In order to cut off the pilot pipe, the flow out of the fluid in the pressure chamber is cut off and the pressure in the pressure chamber increases, and the main valve body is operated in the closing direction to perform an emergency cutoff of the pipe line.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

An emergency shut-off valve 1 provided in a water supply pipe of a water supply system includes a main valve 2 and a control unit for controlling the opening and closing of the main valve 2. The partition wall 4 is partitioned into a primary valve chamber 5 and a secondary valve chamber 6, and a valve port 7 for communicating the primary valve chamber 5 and the secondary valve chamber 6 is provided in the partition wall 4. A main valve body 8 is inserted into the valve port 7 so as to be slidable in the vertical direction. Further, a diaphragm defining a pressure chamber 9 for opening and closing the main valve body 8 is provided on an upper portion of the valve box 3.
The diaphragm 10 is provided with a main valve body 8.
And the diaphragm retainer 11.

The primary valve chamber 5 and the pressure chamber 9 of the main valve 2 communicate with each other via a primary pilot pipe 22 having a strainer 21 interposed therebetween. The secondary valve chamber 6 is a secondary pilot pipe provided with a shut-off pilot valve 31.
Connected via 32. Therefore, a part of the fluid in the primary side valve chamber 5 flows into the pressure chamber 9 from the primary side pilot pipe 22, and from the pressure chamber 9 through the secondary side pilot pipe 32. Leaked to The flow rate of the primary fluid into the pressure chamber 9 and the flow rate of the fluid from the pressure chamber 9 to the secondary side are controlled by adjusting the degree of opening of the needle valves 23, 33 provided in both the pipe lines 22, 32. By appropriately setting the inflow / outflow amount of the pressure chamber 9, the pressure in the pressure chamber 9 is changed to open the main valve body 8, that is, the fluid passing through the main valve 2. It is formed so that the flow rate of can be adjusted arbitrarily.

The circuit for urgently shutting off the main valve 2 thus formed is
An orifice 41 provided on the primary side of the main valve 2, a differential pressure pilot valve 51 that opens when the differential pressure across the orifice 41 rises and allows the primary side fluid to pass through, The above-mentioned shut-off pilot valve that closes by the pressure of the fluid that has passed through the pilot valve 51 and closes the secondary pilot pipe 32
31.

The differential pressure pilot valve 51 includes a valve chamber 52 and a working chamber 53. The valve chamber 52 has an orifice upstream pipe 54 for introducing fluid upstream of the orifice 41, and the shutoff valve. The shut-off pipe 34 leading to the pilot valve 31 is connected, and a valve body 55 for opening and closing the outlet end of the orifice upstream pipe 54 is housed therein. One working chamber
53, the inside is partitioned by a diaphragm 56, the fluid of the orifice upstream side 42 is introduced from the orifice upstream pipe 54 into the upstream chamber 53a on the valve chamber 52 side, and the other downstream chamber 53b is Orifice downstream from orifice line 57 to orifice 41
The fluid on the downstream side 43 is introduced. Further downstream chamber
An adjusting spring 58 for pressing the diaphragm 56 in the closing direction of the valve body 55 is provided in 53b, and an adjusting screw 59 for adjusting the pressing force of the adjusting spring 58 is provided. The valve rod 55a of the valve 55 is connected to the diaphragm 56 in the working chamber 53 through the partition wall 51a, and opens and closes the outlet end of the orifice upstream pipe 54 in conjunction with the movement of the diaphragm 56. It is configured as follows.

Further, the shutoff pilot valve 31 is partitioned by a diaphragm 36 having a valve body 35 for opening and closing the secondary pilot pipe 32, and a valve chamber 52 of the differential pressure pilot valve 51 is provided on a rear side 36 a of the diaphragm 36. Pipe for shut-off operation communicating with
34 is connected. When the fluid on the primary side of the main valve is introduced from the differential pressure pilot valve 51 to the diaphragm back side 36a via the shut-off operation pipe line 34, the diaphragm 36 is actuated by the pressure and the valve 36 is actuated. The secondary pilot pipe 32 is closed by moving the body 35. The pressure in the pipeline 34, that is, the rear side 36a of the diaphragm of the
A release valve 37 is provided to release the fluid pressure.

Next, referring to FIG. 2, the operating state of the emergency shutoff valve 1 configured as described above will be described on the upstream side 42 of the orifice 41.
The pressure difference (P ₁ −P ₂ ) between the fluid pressure P ₁ and the fluid pressure P _{2 on} the downstream side of the orifice 43 is ΔP, the cut-off set differential pressure set by adjusting the adjustment spring 58 is ΔPc, and the main valve 2 is The flow rate of the passing fluid will be described as Q.

The differential pressure ΔP between the fluid pressures P ₁ and P ₂ before and after the orifice 41 changes as the flow rate Q changes, and as the flow rate Q increases, the differential pressure ΔP also increases. That is, the differential pressure ΔP is expressed by a function of the flow rate Q, ΔP = f (Q).

When the flow rate Q is equal to or less than the predetermined flow rate, that is, when the differential pressure ΔP is small and the relationship [differential pressure ΔP <cutoff set differential pressure ΔPc] is satisfied, the valve element 55 of the differential pressure pilot valve 51 By the action of 58, the outlet end of the orifice upstream pipe 54 is closed via the diaphragm 56. Accordingly, since the fluid on the primary side of the main valve is not introduced into the shutoff pilot valve 31, the fluid in the pressure chamber 9 passes through the shutoff pilot valve 31 and flows out to the secondary side of the main valve. The pressure decreases, the main valve body 8 rises, and the main valve 2 is opened.

If the flow rate of the fluid rises abnormally due to damage to the piping on the downstream side, etc.
The differential pressure ΔP around 41 becomes large, and “differential pressure ΔP> cutoff set differential pressure ΔPc” is satisfied. Accordingly, the diaphragm 56 of the differential pressure pilot valve 51, the fluid pressure P ₁ upstream side of the orifice 42, the pressing force of the adjustment spring 58 and the downstream side of an orifice
Moves against the fluid pressure P ₂ of 43, to move the valve member 55 in the opening direction to open the outlet end of the orifice upstream side pipe 54. As a result, the fluid on the primary side of the main valve is introduced into the shut-off pilot valve 31 from the shut-off operation pipe line 34, and the valve body 35 is pressed and moved via the diaphragm 36 in the closing direction of the secondary-side pilot pipe 32, whereby Close the downstream pilot pipe 32. The closing operation of the secondary side pilot pipe 32 causes the fluid 2 in the pressure chamber 9 to flow.
The outflow to the next side stops, the pressure in the pressure chamber 9 increases due to the fluid flowing out from the primary side pilot pipe 22, and the main valve body 8 moves in the closing direction of the valve port 7 to close the main valve 2. .

As described above, the emergency shutoff valve 1 of the present embodiment detects an abnormal increase in the flow rate of the fluid passing through the valve 1 and operates the main valve body 8 in the closing direction by using the pressure of the fluid. As compared with the device using other functional closing means, the variation in the operation due to the mechanical friction is extremely small, and a reliable emergency shut-off operation can be performed. In addition, there is no need for power costs, etc., and it operates reliably even during a power failure.

The emergency shut-off valve 1 that has performed the emergency shut-off as described above retains the fluid pressure on the diaphragm rear side 36a of the shut-off pilot valve 31, so that the cause of the abnormal increase in the fluid flow rate is confirmed, and the predetermined operation is completed. Until the shut-off state can be maintained.

The emergency shut-off valve 1 can be returned to the fluid flow state by opening the release valve 37 of the shut-off operation pipe 34 and releasing the pressure on the diaphragm rear side 36a of the shut-off pilot valve 31.

In addition, opening and closing of the main valve body can be performed by a piston type without using a diaphragm, and each pipe and the like can be appropriately determined according to a location where the valve is installed.

〔The invention's effect〕

As described above, the emergency shutoff valve of the present invention is a differential pressure pilot valve that opens when the differential pressure across the orifice provided on the primary side of the main valve rises and allows the fluid on the primary side to pass. And a shutoff pilot valve for closing the secondary pilot pipe by closing the valve by the pressure of the fluid passing through the differential pressure pilot valve, and performing an emergency shutoff with the pressure of the fluid passing through the emergency shutoff valve. As a result, the variation in operation due to mechanical friction is extremely small as compared with the case using mechanical closing means, and the emergency pilot valve is closed by closing the shut-off pilot valve with the primary pressure. With only a simple configuration, a reliable emergency shutoff operation can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an emergency shutoff valve showing one embodiment of the present invention, and FIG. 2 is a flow sheet for explaining the operation of the emergency shutoff valve. 1 ... Emergency shut-off valve, 2 ... Main valve, 5 ... Primary valve chamber, 6
... secondary valve chamber, 8 ... main valve body, 9 ... pressure chamber, 22 ...
Primary-side pilot piping, 31 ... shut-off pilot valve, 32 ...
… Secondary pilot pipe, 41… Orifice, 51… Differential pressure pilot valve

Claims (1)

(57) [Claims] A main valve element for opening and closing a valve port of the main valve;
A pressure chamber into which the fluid on the secondary side is introduced via a primary-side pilot pipe, and a fluid for leading the fluid in the pressure chamber to the secondary side of the main valve.
An emergency pilot valve that opens and closes the main valve element by leading the fluid in the pressure chamber to the secondary side of the main valve via a secondary pilot pipe and changing the pressure in the pressure chamber. An isolation valve, provided with an orifice on the primary side of the main valve, and a differential pressure pilot valve that opens when the differential pressure across the orifice rises and allows the fluid on the primary side to pass, An emergency shut-off valve provided with a shut-off pilot valve that closes by the pressure of the fluid that has passed through the differential pressure pilot valve and closes the secondary-side pilot pipe.