JP2001108127A - Negative pressure relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative pressure relief valve in a negative pressure- operated apparatus adapted to operate by negative pressure, for introducing positive pressure to prevent breakage of the apparatus when excessive negative pressure is generated. SOLUTION: In this negative pressure relief valve, a relief valve element for opening and closing a passage between a negative pressure port communicated with a negative pressure chamber of the negative pressure operated apparatus and an atmospheric port opened to the atmospheric air is always energized to move in the direction of closing the passage and opened by the negative pressure of a negative pressure control chamber communicated with the negative pressure chamber of the negative pressure operated apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a negative pressure relief valve for introducing a positive pressure when a negative pressure reaches a constant value.

[0002]

2. Description of the Related Art Relief valves for releasing pressurized fluid to the atmosphere (low pressure side) when the positive pressure in a pipeline exceeds a predetermined value are widely used in pressure pipelines. On the other hand, in a pressure device that utilizes negative pressure, for example, a negative pressure container is set to have a large thickness and shape so that it can withstand the magnitude of a possible negative pressure, and thus must be heavy and large. However, the negative pressure required by the negative pressure utilization equipment is almost always not as large as the negative pressure resistance set in the negative pressure container, and the negative pressure container has room for reduction in size and weight. That is, if the set negative pressure resistance of the negative pressure container is reduced, the weight and size can be reduced.

[0003]

SUMMARY OF THE INVENTION The present invention has been made based on the awareness of problems with such a negative pressure operating device and a negative pressure vessel, and when the negative pressure exceeds a predetermined value, that is, when the negative pressure becomes equal to or lower than the predetermined value, a positive pressure is applied. It is intended to obtain a negative pressure relief valve capable of introducing pressure.

[0004]

SUMMARY OF THE INVENTION A negative pressure relief valve according to the present invention comprises a negative pressure port communicating with a negative pressure chamber of a negative pressure operating device and an atmospheric port open to the atmosphere; a flow passage between the negative pressure port and the atmospheric port. A relief valve body that opens and closes; a negative pressure control chamber that communicates with a negative pressure chamber of a negative pressure operating device and that exerts a moving force on the negative pressure relief valve in the direction of opening the flow path by the negative pressure of the negative pressure chamber; Spring means for constantly moving and biasing the body in a direction to close the flow passage against the force exerted by the negative pressure of the negative pressure control chamber.
According to this negative pressure relief valve, when the negative pressure in the negative pressure control chamber becomes large enough to overcome the spring force of the spring means, the positive pressure is introduced from the atmospheric port and the negative pressure decreases (the pressure in the negative pressure chamber increases. ), It is possible to prevent the equipment from being damaged by an excessively large negative pressure.

[0005] A passage for communicating the negative pressure control chamber with the negative pressure chamber of the negative pressure operating device can be arbitrarily formed. However, if it is formed in a relief valve, a connection connecting the negative pressure port and the negative pressure operating device is formed. A conduit can be used. In this case, in order not to pick up the pressure fluctuation near the negative pressure port of the connection pipe,
It is desirable to form a negative pressure introducing pipe extending into the connecting pipe line integrally with the relief valve body. For the same reason, it is desirable to form an orifice in a passage communicating between the negative pressure control chamber formed in the relief valve body and the negative pressure chamber of the negative pressure operating device.

It is preferable that the spring means for urging the relief valve element comprises a pressure adjusting spring mechanism for adjusting a moving force of the relief valve element in the flow path closing direction.

[0007]

FIG. 1 shows a first embodiment of a negative pressure relief valve according to the present invention. Valve body 10
Is composed of a main body 11 and a sub-body 12 screwed and fixed to the main body 11. The main body 11 has an atmosphere port 13, a negative pressure port 14,
A valve hole 15 in which the atmosphere port 13 communicates with the negative pressure port 14 and a relief valve body 20 is slidably fitted is formed. The atmosphere port 13 communicates with the atmosphere via the filter 17, and the negative pressure port 14 communicates with the negative pressure chamber 31 of the negative pressure operating device 30 via the connection pipe 18. The negative pressure chamber 31 is connected to a negative pressure source 33 via a control valve 32. The negative pressure operating device 30 includes a negative pressure chamber 31,
It is a device that makes a negative pressure by the negative pressure generated by the negative pressure source 33 and performs some work with the negative pressure, and its specific example is not limited.

At the end of the valve hole 15 on the side of the negative pressure port 14,
A valve seat 19 having a tapered portion that decreases in diameter toward the negative pressure port 14 is fixed. A valve element 21 is provided. A negative pressure control chamber 16 is formed at the end of the relief valve body 20 on the opposite side of the elastic valve body 21 by the telescopic sealing body 40 and the sub-body 12. The telescopic sealing body 40 includes a metal bellows 41 having one end fixed to the upper end of the relief valve body 20 in the drawing, and a retainer ring 4 integrally provided at the other end of the metal bellows 41.
2 is sandwiched between the main body 11 and the sub-body 12. 43 is the retaining ring 42 and the main body 1
1, a seal member provided between the sub-body 12 and the sub-body 12.

The relief valve body 20 has a valve body passage 22 formed in a shaft portion thereof to connect the connection pipe line 18 (negative pressure chamber 31) and the negative pressure control chamber 16 to each other. An orifice 23 is formed in the valve passage 22 so as to reduce the pulsation (pressure fluctuation) of the connection pipe line 18 (negative pressure chamber 31) from reaching the negative pressure control chamber 16 side. Further, the relief valve body 20 is provided with a negative pressure introducing pipe 24 which communicates with the valve body passage 22 and extends into the connection pipe line 18. The negative pressure introducing pipe 24 prevents the pressure fluctuation near the negative pressure port 14 from being applied to the valve body passage 22.

The relief valve body 20 is urged by a pressure adjusting spring mechanism 50 to move in a direction in which the elastic valve body 21 is seated on the valve seat 19. The pressure adjusting spring mechanism 50 includes a compression spring 51 inserted into the negative pressure control chamber 16, a retainer 52 of the compression spring 51, and a pressure adjusting knob screwed to the sub-body 12 for adjusting the position of the retainer 52. 5
3 is provided. When the screwing amount of the pressure adjusting knob 53 is adjusted, the position of the retainer 52 changes, and as a result, the force in the valve closing direction applied to the relief valve body 20 by the compression spring 51 changes.

The negative pressure relief valve having the above-described structure, when connected to the negative pressure operating device 30 as shown in FIG.
The negative pressure in the chamber is controlled by the negative pressure control chamber 1
6 within. However, the force in the valve opening direction exerted on the relief valve body 20 by the negative pressure is always smaller than the force in the valve closing direction by the pressure adjusting spring mechanism 50, and the elastic valve body 21 of the relief valve body 20 is applied to the valve seat 19. I'm sitting. Therefore, the supply of the positive pressure to the negative pressure chamber 31 is not performed.

On the other hand, for some reason, the negative pressure in the negative pressure chamber 31 exceeds a certain value, and the force in the valve opening direction applied to the relief valve body 20 via the negative pressure control chamber 16 is applied to the pressure adjusting spring mechanism. When the force of 50 is overcome, the relief valve 20
The valve is opened while the compression spring 51 is flexed, and the atmosphere from the atmosphere port 13 is guided to the negative pressure chamber 31. Therefore, generation of an excessively large negative pressure is prevented. When the negative pressure in the negative pressure chamber 31 returns to the allowable value, the relief valve body 20 returns to the valve closing position by the pressure adjusting spring mechanism 50, and the introduction of the atmosphere into the negative pressure chamber 31 is stopped. As a result of the above operations being repeated, the negative pressure in the negative pressure chamber 31 is kept in a certain range. Orifice 23
And the negative pressure introducing pipe 24 filters the pressure fluctuation in the negative pressure chamber 31 and acts on the negative pressure control chamber 16 to prevent pulsation of the relief valve body 20. The valve opening start pressure of the relief valve body 20 can be adjusted by the pressure adjusting spring mechanism 50.

FIG. 2 shows a second embodiment of the negative pressure relief valve according to the present invention. This embodiment is different from the first embodiment in that a main body 11 and a sub-body 12 are connected by a lock ring 10 ', a negative pressure control chamber 16 is formed by a rolling diaphragm 16R and a sub-body 12, except for a relief valve. Body passage 2 in body 20
2. Instead of providing the negative pressure introducing pipe 24, a negative pressure introducing pipe 3
4, the point that the negative pressure chamber 31 of the negative pressure operating device 30 and the negative pressure control chamber 16 are connected, and that the negative pressure control chamber 16 is formed without providing the expandable sealing body 40 is different from the first embodiment. This is the main difference. The components having the same functions as those of the first embodiment are denoted by the same reference numerals. According to this embodiment, a negative pressure relief function basically similar to that of the first embodiment can be obtained.

[0014]

As described above, the negative pressure relief valve of the present invention is connected to a negative pressure operating device which operates at a negative pressure, thereby preventing an excessive negative pressure from occurring and preventing the device from operating. Breakage can be prevented, and the set negative pressure resistance of the negative pressure container can be reduced, thereby reducing the size and weight.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a negative pressure relief valve according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the negative pressure relief valve according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Valve body 11 Main body 12 Subbody 13 Atmospheric port 14 Negative pressure port 15 Valve hole 16 Negative pressure control chamber 17 Filter 18 Connection pipeline 19 Valve seat 20 Relief valve 21 Elastic valve 22 Valve passage 23 Orifice 24 Negative pressure introduction Pipe 30 Negative pressure operating device 31 Negative pressure chamber 32 Control valve 33 Negative pressure source 40 Telescopic seal 41 Metal bellows 42 Retainer ring 50 Pressure adjustment spring mechanism 51 Compression spring 52 Retainer 53 Pressure adjustment knob

Claims (4)

[Claims] A negative pressure port communicating with a negative pressure chamber of a negative pressure operating device; an atmospheric port open to the atmosphere; a relief valve for opening and closing a flow path between the negative pressure port and the atmospheric port; A negative pressure control chamber which communicates with a negative pressure chamber of the operating device and exerts a moving force in a direction of opening the flow path on the negative pressure relief valve by the negative pressure of the negative pressure chamber; A negative pressure relief valve comprising: spring means for constantly moving and biasing the flow path in a direction to close the flow path against a force exerted by a negative pressure of the chamber. 2. The relief valve according to claim 1, wherein a passage for communicating the negative pressure control chamber and the negative pressure chamber of the negative pressure operating device is formed in the relief valve body. A negative pressure relief valve integrally provided with a negative pressure introducing pipe extending into a connection conduit connecting the negative pressure port and the negative pressure operating device. 3. The negative pressure relief valve according to claim 2, wherein an orifice is formed in a valve body passage that communicates a negative pressure control chamber formed in the relief valve body with a negative pressure chamber of the negative pressure operating device. Negative pressure relief valve. 4. The negative pressure relief valve according to claim 1, wherein said spring means comprises a pressure adjusting spring mechanism for adjusting a moving force of said relief valve body in a flow path closing direction. Pressure relief valve.