JPS6225583Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a differential emergency safety valve.

When transferring crude oil, etc., in order to maintain safety, an emergency shutoff valve is installed in the transfer pipe and is closed in the event of an emergency such as a crack in the transfer pipe or a fire. becomes abnormally high pressure.
In order to prevent this abnormally high pressure, a bypass pipe is provided that communicates with the discharge side and the suction side of the pump, and a safety valve that opens when detecting abnormally high pressure on the discharge side is provided in the pipe. This kind of safety valve was first developed in 1972.
A direct-acting emergency safety valve, as shown in Japanese Patent No. 16630, and a differential emergency safety valve, which apply differential pressure to both sides of a piston and release one of them in an emergency to perform sudden switching, are well known. However, in both types, the spool valve that switches the valve body has a structure in which it engages with a movable part installed in the safety valve to perform the switching operation, so it has the disadvantage that it is difficult to adjust its operation. have. Further, since the spool valve must perform all the complicated switching operations by itself, its structure is complicated, and commercially available spool valves with simple structures cannot be used.

This invention was devised in view of the above-mentioned points, and the object is to provide a differential emergency safety valve that has a simple structure and reliable operation.

This idea consists of a valve body that has a bypass pipe that communicates with the discharge side and suction side of the pump, and a double-acting cylinder that has two chambers separated by a piston with different pressure-receiving areas on both end faces. a switching valve that supplies the pressure of an air supply source to the two chambers of the cylinder, and a valve that closes the bypass pipe in conjunction with the piston due to a difference in pressure acting on the pressure receiving surface of the piston; A quick exhaust valve is connected to the cylinder for releasing the back pressure of the cylinder to the atmosphere when the valve slides in the valve opening direction together with the piston due to abnormally high pressure on the discharge side of the pump, and each input side is connected to the air supply. A manual reset valve and a mechanical valve are provided, which are connected to a power source and selectively apply the pressure as switching driving force to the switching valve, and the mechanical valve is provided outside the valve body, and the mechanical valve is connected to the valve and the piston. The present invention is characterized in that one end of a rod that interlocks and connects the valve body is made to protrude outside the valve body, and an actuating part for switching the mechanical valve is provided on the protruding part. Therefore,
A constant pressure from the air supply source is supplied to the two chambers of the cylinder, and the pressure difference due to the difference in the pressure receiving area of the piston causes the valve to close and close the bypass line to maintain the normal transfer state, but the pressure on the discharge side of the pump When the pressure reaches an abnormally high pressure, the valve opens integrally with the piston and rod, circulating the pressure on the discharge side to the suction side, and at this time, the back pressure of the cylinder is released from the rapid exhaust valve to the atmosphere, causing an abnormality. High pressure can be quickly relieved to ensure safety, and the actuating part automatically switches the mechanical valve by the operation of the valve and piston to automatically switch the switching valve between the air supply source and the cylinder. Since the and actuating part are provided outside the valve body, assembly and adjustment of both can be done extremely easily.
The mechanical valve is configured so that it can be easily manufactured using commercially available products along with a reset valve and a switching valve.

An embodiment of this invention will be described based on the drawings. 1 is a pump, and transfer pipes 4 and 5 are connected to a suction side 2 and a discharge side 3 of the pump 1. A valve body 6 is fixed to this pump 1. As shown in FIG. 2, this valve body 6 is formed with a connecting portion 7 that communicates with the discharge side 3 and a connecting portion 8 that communicates with the suction side 2, so that the connecting portions 7 and 8 are in communication with each other. As a result, a bypass conduit 9 is formed. Piston 1 provided in cylinder 10 of valve body 6
1 and a valve 13 connected to the valve seat 12 of the connecting portion 8 are connected by a rod 14 and are provided so as to be movable up and down. This valve 13 has a stepped portion formed on its outer periphery to form an annular pressure receiving surface 15 that receives the discharge pressure of the pump 1 . In addition, this valve 1
3 is fitted into the connecting portion 8 so as not to communicate with the bypass conduit 9 if it rises within 2 mm. The cylinder 10 is divided into two chambers 16 and 17 by the piston 11.
It is divided into In this piston 11, the diameter of the rod 14 is changed on the upper and lower sides, so that the area of the pressure receiving surface 19 on the lower end surface is smaller than the area of the pressure receiving surface 18 on the upper end surface, and the difference is the area of the pressure receiving surface 15 of the valve 13. Match.

Thus, switching valves 21 and 22 whose input sides are connected to the air supply source 20 and another switching valve 23 are provided. Output ports of the switching valves 22 and 23 are connected to the chamber 17 via a throttle valve 24,
The output port of the switching valve 21 is connected to the cylinder 1 through a pressure reducing valve 25 that can freely adjust the pressure and a rapid exhaust valve 26.
0 chamber 16, and a pressure gauge 27 is provided in its path. Furthermore, there are provided a reset valve 28, a manual valve 29, and a mechanical valve 30, each of which has its input side connected to the air supply source 20. The reset valve 28 has a push button 31, and by pressing the push button 31, the pressure of the air supply source 20 is applied as a switching driving force to the switching valves 21 to 23 via the shuttle valve 32 and the switching valve 33. be. Manual valve 29
By pressing the push button 34, the pressure of the air supply source 20 is applied to the switching valve 33 as switching driving force. The mechanical valve 30 applies the pressure of the air supply source 20 to the switching valves 21 to 23 as switching driving force via the shuttle valve 32 and the switching valve 33 by its switching operation. One end of the rod 14 protrudes from the valve body 6, and an operating portion 35 for switching the mechanical valve 30 is fixed to the protruding end.

In such a configuration, the reset valve 28
When the push button 31 is pressed, the pressure of the air supply source 20 is applied to the switching valves 21 to 23 as switching driving force. That is, the switching valve 21 is opened, and the pressure of the air supply source 20 is supplied to one chamber 16 of the cylinder 10 at a constant pressure regulated by the pressure reducing valve 25.
The constant pressure is supplied to the other chamber 17 of the cylinder 10 via the open switching valve 23. Also,
The switching valve 22 is maintained in a closed state. At this time,
Although the air pressure per unit area supplied to the chambers 16 and 17 is constant, the pressure receiving surfaces 18 and 1 of the piston 11
The force pushing down the piston 11 due to the difference in the area of 9
P ₁ is larger than the force P ₂ that pushes up the piston 11.
As a result, the bypass line 9 is closed by the valve 13. Due to the downward movement of the rod 14 at this time, the mechanical valve 30 is switched by the operating section 35, and the pressure of the air supply source 20 continues to be applied to the switching valves 21 and 23 instead of the reset valve 28 as switching driving force. Therefore, reset valve 2
Even if you release your hand from the push button 31 of 8, the bypass pipe 9
can be maintained in a closed transport state. Then, when the internal pressure on the discharge side 3 increases abnormally and the force _P3 pushing up the pressure receiving surface 15 of the valve 13 reaches more than the difference between _P1 and _P2 , the valve 13 rises together with the piston 11 and the rod 14, and the bypass pipe Channel 9 is opened to circulate crude oil to the discharge side 2. At the beginning of this operation, if the valve 13 moves within 2 mm, the bypass line 9 will not open, and the rod 14 will open.
In the upward movement of mm, the mechanical valve 30 is switched by the actuator 35, so that the chamber 17 is supplied with the pressure of the air supply 20 and the chamber 16 is also supplied with the pressure of the air supply 20.
The pressure is released to the atmosphere from the rapid exhaust valve 26, so that the opening operation of the valve 13 is performed extremely quickly while preventing chattering, and the abnormally high pressure is eliminated. That is, the mechanical valve 30 that has been closed by the actuator 35 cuts off the pressure supply of the air supply source 20 to the switching valves 21 to 23. As a result, the switching valve 21 cuts off the pressure supply to the closed chamber 16, and the switching valve 23 also cuts off the pressure supply to the closed chamber 16. The switching valve 22 opens to supply the pressure of the air supply 20 to the chamber 17 . At this time, the switching timing of the mechanical valve 30 can be easily adjusted because the valve 30 and the actuating section 35 are provided outside the valve body 6, and assembly is also simple.

In addition, the mechanical valve 30 is connected to the air supply source 20.
The switching valves 21 to 23 use the pressure from the
When the push button 34 of the manual valve 29 is pressed while the air supply continues to be applied and the valve 13 is opened, the air supply source 2
The switching valve 33 is switched using the pressure of 0 as the switching driving force, and the switching valves 21 to 23 are switched from the mechanical valve 30.
The air supply source 20 was applied as a switching driving force to
Cut off the pressure. With this, as described above, from the switching valve 22 to one chamber 1 of the cylinder 10.
7 can be supplied with air pressure to open the valve 13.

Also, balance is achieved when P ₁ = P ₂ + P ₃ , and P ₁
<P ₂ +P ₃ , the valve 13 is opened, but the area A 2 of the pressure receiving surface 19 is made smaller than the area A ₁ of the pressure receiving surface 18 of the piston 11, and the area A ₃ of the pressure receiving surface 15 of the valve ₁₃ is
By setting A to the difference between A ₁ and A ₂ , the pressure reducing valve 25 is adjusted to have an internal pressure per unit area equal to the set pressure to maintain the transfer pipe 5, and the supply pressure to the cylinder 11 is adjusted to the pressure gauge 27. It can be displayed by tilting it.

Since this device is configured as described above, the operation of the valve is controlled using the pressure difference acting on the pressure receiving surface of the piston, so the pressure of the air supply source does not need to be low, and the abnormally high pressure of the pump can be absorbed by the bypass pipe. This can be solved by opening the air passage, but while maintaining the air supply to the chamber with a small pressure receiving area of the cylinder, the back pressure is released to the atmosphere by the rapid exhaust valve to prevent the valve opening operation from chattering. It is possible to quickly perform the pump discharge pressure while also eliminating abnormally high pump discharge pressure, and
A mechanical valve that applies switching driving force to the switching valve in order to switch the switching valve in conjunction with the movement of the valve and piston, and an actuating part that switches this mechanical valve are provided outside the valve body. In addition to being able to accurately and easily adjust the operating timing, when the abnormally high pressure is resolved, the switching valve can be switched by simply operating the reset valve, and the piston and valve can be moved in the direction of closing. This has the advantage that mechanical valves can be easily manufactured using commercially available popular products together with reset valves and switching valves.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is a side view, and FIG. 2 is a pipe diagram. 1...Pump, 2...Suction side, 3...Discharge side,
6...Valve body, 9...Bypass pipe line, 10...Cylinder, 11...Piston, 13...Valve, 14...
...Rod, 16-17...Chamber, 18-19...Pressure receiving surface, 20...Air supply source, 21-23...Switching valve, 26...Rapid exhaust valve, 28...Reset valve, 30...Mechanical Valve, 35...actuating part.

Claims (1)

[Scope of utility model registration request] A bypass pipe connecting the discharge side and suction side of the pump is provided, and a valve body is provided in which a double-acting cylinder having two chambers partitioned by a piston having different pressure receiving areas on both end faces is formed, and the cylinder A switching valve that supplies the pressure of the air supply source to the two chambers via a pressure-adjustable pressure reducing valve or supplies the pressure of the air supply source only to the chamber with a small pressure receiving area, and acts on the pressure receiving surface of the piston. and a valve having a pressure receiving surface that closes the bypass line in conjunction with the piston due to a pressure difference and receives the discharge pressure of the pump, and the valve opens together with the piston due to abnormally high pressure on the discharge side of the pump. A quick exhaust valve is connected to the cylinder, and each input side is connected to the air supply source to selectively use the pressure as a switching driving force to selectively operate the switching valve. A manual reset valve and a mechanical valve are provided, and the mechanical valve is provided outside the valve body, and one end of a rod that interlocks and connects the valve and the piston is made to protrude outside the valve body. A differential emergency safety valve characterized in that an actuating part for switching the mechanical valve is provided on the protruding part.