JPH07104865A - Pressure control valve - Google Patents

Abstract

PURPOSE:To provide a pressure control valve which can close a valve element when a diaphragm is broken. CONSTITUTION:The pressure control valve 1 is composed of main body 2 of the valve, a diaphragm 21 for performing the valve closing drive of a valve element 5 when the operating pressure of a pressure chamber 20 is increased and for performing the valve opening drive of the valve element when the operating pressure is decreased, throttle 36 for throttling a flow rate to be supplied to the pressure chamber 20, pilot valve 33 for decreasing the operating pressure of the pressure chamber 20 by letting the fluid in an operating pressure introducing duct 34 flow out to the downstream of the valve main body 2 when secondary pressure is higher than a set pressure and for increasing the operating pressure of the pressure chamber 20 by stopping the flowing-out of the fluid in a primary pressure supplying duct 31 when the secondary pressure is lower than the set pressure, and variable throttle 39 arranged at the operating pressure supplying duct 34 so as to decrease the flow rate of the fluid flowing from the pressure chamber 20 to the pilot valve 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control valve, and more particularly to a pressure control valve configured to operate a diaphragm in response to fluctuations in secondary pressure to control the pressure.

[0002]

2. Description of the Related Art For example, in a pressure control valve which is installed in a city gas supply line or the like and controls the pressure so that the supply pressure to the downstream side is constant, a seat portion (valve body) is provided at the center of a diaphragm. When the amount of gas used on the downstream side is reduced, the pressure in the pressure chamber defined by the diaphragm is increased, and the seat portion is closed to reduce the gas supply amount. Further, when the amount of gas used on the downstream side increases, the pressure in the pressure chamber drops and the seat portion is displaced in the valve opening direction to increase the gas supply amount. In this way, the seat portion is separated from and seated on the valve seat together with the diaphragm that is displaced by the differential pressure between the working pressure P _L of the pressure chamber and the primary pressure P ₁ of the upstream flow passage to control the supply amount to the downstream side. To do.

[0003]

DISCLOSURE OF THE INVENTION The above conventional pressure control valve
, The secondary pressure P during pressure control₂Is the set pressure P
₀When the pressure drops below, the fluid in the pressure chamber
By pressure control operation, it flows out to the downstream and becomes the operating pressure of the pressure chamber.
Primary pressure P₁The differential pressure between and becomes large. Therefore, the pressure chamber
Working pressure P_LIs the primary pressure P₁Lower than (P_L<P₁)
The diaphragm opens due to the large differential pressure.
Directional to increase the downstream fluid supply. Reverse
Operating pressure P_LIs the primary pressure P₁Is close to the differential pressure is small
The diaphragm, the diaphragm moves in the valve closing direction to supply the fluid.
Squeeze the amount.

However, if the diaphragm is damaged,
Since the fluid in the upstream flow path passes through the damaged portion of the diaphragm and flows into the pressure chamber, the working pressure P _L of the pressure chamber does not drop and the differential pressure between the working pressure and the primary pressure P ₁ becomes small. As a result, the secondary pressure P ₂ cannot be controlled to the set pressure P ₀ .

Further, if the size of the hole at the damaged portion of the diaphragm is small, the outflow amount flowing out through the pressure supply pipe line becomes larger than the inflow amount from the damaged portion. In that case, the operating pressure P _L of the pressure chamber does not rise (P _L <
P ₁ ), the differential pressure does not become smaller than a certain value, and the diaphragm and the valve body remain in the open state, and the valve cannot be closed without pressure control.

Therefore, an object of the present invention is to provide a pressure control valve that solves the above problems.

[0007]

According to the present invention, there is provided a valve body having a flow passage partitioned by a valve seat into an upstream flow passage and a downstream flow passage,
A space in the valve body is defined by the upstream flow path and the pressure chamber,
When the differential pressure between the operating pressure of the pressure chamber and the primary pressure of the upstream flow passage is small, the valve body is driven in the valve closing direction in which it abuts against the valve seat, and when the differential pressure is large, the valve body is A diaphragm that is driven in the valve opening direction away from the valve seat and an upstream side 1
A primary pressure supply system path for supplying a secondary pressure to the pressure chamber, a secondary pressure supply system path for supplying a secondary pressure on the downstream side to the pressure chamber, and a primary pressure supply system path, A first throttle for restricting the flow rate supplied to the pressure chamber; and a fluid in the secondary pressure supply system passage for flowing out to the downstream of the valve body when the secondary pressure downstream of the valve body becomes equal to or higher than a set pressure. To lower the operating pressure of the pressure chamber, and prevent the fluid in the primary pressure supply system passage from flowing out to the downstream of the valve main body when the secondary pressure is equal to or lower than the set pressure, thereby reducing the operating pressure of the pressure chamber. It is characterized by comprising a pilot valve for raising and a second throttle which is arranged in the secondary pressure supply system passage and reduces the flow rate of the fluid flowing from the pressure chamber to the pilot valve.

[0008]

By providing the second throttle for reducing the flow rate of the fluid flowing from the pressure chamber to the pilot valve in the secondary pressure supply system passage connecting the pilot valve and the pressure chamber, the outflow amount from the pressure chamber is reduced. Therefore, when the diaphragm is damaged, the amount of inflow from the damaged part becomes larger than the amount of outflow, and the differential pressure between the working pressure of the pressure chamber and the primary pressure of the upstream flow path is reduced to reduce the diaphragm and valve. The body can be closed.

[0009]

1 and 2 show a first embodiment of the pressure control valve according to the present invention.

In both figures, the pressure control valve 1 is provided, for example, in a gas supply line, and causes the valve body 5 to open and close the valve seat 4 provided in the flow path 3 in the valve body 2. As a result, the pressure on the downstream side is controlled to be constant.

The valve body 2 has an upstream side flange 2a to which the upstream side pipe 6 is connected on the left side and a downstream side pipe 7 on the lower side.
Is connected to the downstream side flange 2b. An inlet 2c that communicates with one end of the flow path 3 in the center of the upstream flange 2a.
Is opened, and an outlet 2d communicating with the other end of the flow path 3 is opened at the center of the downstream side flange 2b.

The flow path 3 is divided into an upstream flow path 3a communicating with the inflow port 2c and a downstream flow path 3b communicating with the outflow port 2d by a partition wall 8 formed across the inside of the valve body 2. Well defined. Here, the pressure in the upstream flow path 3a is represented as a primary pressure P ₁ , and the pressure in the downstream flow path 3b is represented as a secondary pressure P ₂ . In this embodiment, for example, the primary pressure P ₁ = 70 kg / cm ²
And is set to a fairly high pressure.

The valve seat 4 is formed in a ring shape and is fitted in a central hole 9 formed in the partition wall 8. The collar portion projecting radially from the outer periphery is tightened with a bolt 10 to partition wall 8. It is fixed to.

Below the valve seat 4, a cage guide 11 is provided.
Is provided. The cage guide 11 is formed in a cylindrical shape and has a plurality of elongated holes 11 penetrating its inner circumference and outer circumference.
a. The plurality of long holes 11a are provided along the entire circumference of the cage guide 11 at regular intervals and also function as throttles. When the valve body 5 opens, the fluid flow is throttled to reduce the flow velocity. Therefore, even if the primary pressure P ₁ is set to a high pressure, the flow velocity passing through the valve seat 4 is decelerated, which facilitates pressure control in the small flow rate region.

The valve body 5 comprises a piston 12 slidably provided above the valve seat 4 in a vertical direction, and a cage 13 integrally provided below the piston 12 by a bolt 14. Combined. The piston 12 has a seat portion 12a on its lower surface, which comes into contact with the valve seat 4 during the valve closing operation. The cage 13 is fitted to the inner circumference of the cage guide 11 described above to guide the sliding movement of the piston 12.

A plurality of openings 13a through which the fluid passes are formed on the peripheral surface of the cage 13. The opening 13a is formed in a trapezoidal shape, and the opening area increases according to the amount of movement of the valve body 5. That is, when the valve body 5 starts the valve opening operation, the opening area is small and the flow rate passing through the valve seat 4 is narrowed. As the valve opening degree of the valve body 5 increases, the opening area increases and the flow rate increases. Will increase.

Therefore, when the valve body 5 starts the valve opening operation, the flow rate does not suddenly increase, and the flow rate gradually increases with the valve opening operation of the valve body 5, and the pressure control in the small flow rate range is performed. It's easier to do.

A cylindrical perforated plate 15 is arranged around the cage 13. The perforated plate 15 has a large number of holes on its outer peripheral surface. Therefore, the fluid (gas in this embodiment) that has passed through the valve seat 4 from the upstream side flow passage 3 a passes through the holes of the perforated plate 15, flows out to the downstream side flow passage 3 b, and passes through the holes of the perforated plate 15. Is rectified in the process.

A position detecting rod 16 extending in the vertical direction is fixed to the center of the piston 12 by a bolt 17. The position detection rod 16 has a lid 18 at the upper end 16a.
Of the valve body 5 can be known in accordance with the sliding position of the upper end 16a.

The lid 18 for closing the upper opening 2e of the valve body 2 is
It is fixed to the valve body 2 with bolts 19. Valve body 5 and lid 1
A pressure chamber 20 is formed between the pressure chamber 20 and the pressure chamber 8, and a pressure introducing hole 18a for introducing pressure to the pressure chamber 20 is formed on the outer periphery of the lid 18.

Reference numeral 21 denotes a rubber diaphragm, the outer peripheral portion of which is sandwiched between a ring-shaped diaphragm retainer 22 and a step portion 2f provided on the upper surface of the valve body 2, and the inner peripheral portion of which is above the piston 12. It is sandwiched between the end face and the ring-shaped diaphragm retainer 23. Therefore, since the diaphragm 21 defines the space between the pressure chamber 20 and the upstream flow passage 3a, the operating pressure P _L of the pressure chamber 20 and one of the upstream flow passage 3a.
It is displaced according to the magnitude of the differential pressure from the next pressure P ₁ . Further, the diaphragm 21 has an expanding / contracting portion bent in a U shape between the outer periphery of the valve body 5 and the inner wall of the valve body 2, and allows the valve body 5 to move up and down, that is, to open and close the valve. It is configured to do.

Reference numeral 24 denotes a spring retainer, which abuts on an upper end portion of a piston pressing spring 25 for pressing the piston 12 against the valve seat 4. The spring retainer 24 is fitted in the central hole 18b of the lid 18, has a recess 24a at the bottom against which the upper end of the piston pressing spring 25 abuts, and a bearing 27 for bearing the position detection rod 16 is fitted at the center. are doing. Also, the piston pressure spring 2
The lower end of 5 is in contact with a ring 26 fitted in the recess 12b of the piston 12. Therefore, the valve body 5 is biased in the valve closing direction by the pressing force of the spring 25.

Reference numeral 28 denotes a valve opening display member, which is screwed to the upper surface of the lid 18 so as to cover the upper end flange portion of the spring retainer 24 with the lid 18.
To the upper surface of. The valve opening display member 28 includes a scale 28a for displaying the valve opening and a window 28 for viewing the scale 28a.
b and. The upper end 16 of the position detection rod 16 described above
a can be visually recognized from the window 28b of the valve opening degree display member 28. Therefore, the valve opening degree of the valve body 5 can be known by reading the scale 28a corresponding to the sliding position of the upper end 16a.

Reference numeral 30 denotes a pressure control section, which is a primary pressure supply line.
(Primary pressure supply system line) 31 and secondary pressure supply line (secondary pressure supply line)
Pressure supply system path) 40 and bleed pressure is released to the downstream side
Bleed line 32, pilot valve 33, pressure chamber 20
Primary pressure P₁Or secondary pressure P ₂Introduce working pressure
Downstream detection pressure to the inlet pipe 34 and the pilot valve 33
(Secondary pressure P₂) Is supplied to the detection line 35.

One end of the primary pressure supply pipeline 31 is connected to the primary connection port 6a of the upstream pipe 6, and the other end is a branch point between the secondary pressure supply pipeline 40 and the working pressure introduction pipeline 34. 41 is connected. A throttle (first throttle) that limits the flow rate from the upstream pipe 6 is provided in the middle of the primary pressure supply pipe 31.
36 are provided.

One end of the operating pressure introducing pipe 34 is a branch point 41 between the primary pressure supplying pipe 31 and the secondary pressure supplying pipe 40.
, And the other end is connected to the pressure introducing hole 18 a of the lid 18. Therefore, the gas having the primary pressure P ₁ or the secondary pressure P ₂ whose flow rate is limited by the throttle 36 is supplied to the pressure chamber 20 and serves as both the primary pressure supply system path and the secondary pressure supply system path. There is.

The secondary pressure supply conduit 40 has a branch point 41 at one end with the primary pressure supply conduit 31 and the working pressure introducing conduit 34.
, And the other end is connected to the nozzle 33f of the pilot valve 33.

The pilot valve 33 is a pair of diaphragms 3.
Upper chamber 33c, middle chamber 33d, lower chamber 33 by 3a and 33b
It is defined by e. A nozzle 33f connected to the secondary pressure supply pipe 40 is provided in the middle chamber 33d, and the lower chamber 33e
A coil spring 33g for pressing the diaphragm 33b is interposed between the two. The coil spring 33g has its spring force changed by turning the adjusting screw 33h to adjust the pilot set pressure P ₀ .

Therefore, the secondary pressure P ₂ downstream of the pressure control valve 1 is set to a predetermined pressure by adjusting the pilot set pressure.

The pair of diaphragms 33a and 33b are connected to each other and are displaced in the same direction, and the diaphragm 33a is nozzle 33f due to the pressure rise in the upper chamber 33c.
The flow rate flowing out further is throttled, and the flow rate flowing out from the nozzle 33f is increased by the pressure drop in the upper chamber 33c.

One end of the bleed pipe 32 is the pilot valve 3
3 is connected to the inner chamber 33d, and the other end is connected to the secondary side connection port 7a of the downstream side pipe 7. Therefore, the gas supplied to the inner chamber 33d escapes to the downstream side pipe 7 through the bleed conduit 32.

One end of the detection conduit 35 is the pilot valve 3
3 is connected to the upper chamber 33c, and the other end is connected to the secondary side connection port 7b of the downstream side pipe 7. Therefore, the upper chamber 33c of the pilot valve 33 has a pressure corresponding to the change in the secondary pressure P ₂ on the downstream side.

Further, in the working pressure introducing pipe 34, a check valve 37 which allows only the flow of gas from the primary pressure supply pipe 31 in the direction of flowing into the pressure chamber 20, and an upstream of the check valve 37. Bypass pipe 38 that bypasses the downstream side and the downstream side, and a variable throttle (second throttle) that throttles the flow rate of the bypass pipeline 38.
39 are provided. The variable throttle 39 is adjusted so that the throttle area ratio is smaller than the throttle area ratio of the throttle 36 provided in the primary pressure supply conduit 31.

Therefore, the primary pressure P ₁ from the primary pressure supply line 31 is supplied to the pressure chamber 20 through both the check valve 37 and the variable throttle 39. However, when the secondary pressure P ₂ falls below the set pressure P ₀ , the gas in the primary pressure supply pipe line 31 flows out to the downstream side pipe 7 via the pilot valve 33.

Since the throttle area ratio of the variable throttle 39 is set smaller than that of the throttle 36, the gas downstream of the throttle 36 does not flow out to the pilot valve 33 side, and the gas in the pressure chamber 20 passes through the variable throttle 39. It flows out to the pilot valve 33 side.
As a result, the operating pressure P _L of the pressure chamber 20 is reduced and falls below the primary pressure P ₁ .

Therefore, the diaphragm 21 is pushed upward by the primary pressure P ₁ of the upstream side flow passage 3a and the valve body 5 is pushed up.
Moves in the valve opening direction. Therefore, the flow rate of the gas from the upstream flow passage 3a passing through the valve seat 4 and flowing out to the downstream flow passage 3b increases, and the secondary pressure P ₂ rises to the set pressure P ₀ .

Here, the pressure control operation of the pressure control valve 1 having the above structure will be described.

Primary pressure P on the upstream side₁Is upstream of the valve seat 4
Is supplied to the upstream side flow path 3a of the
The pressure chamber 20 is connected via the conduit 31 and the operating pressure introducing conduit 34.
Supplied within. Therefore, on the lower surface of the valve body 5, there is an upstream pipe line.
Primary pressure P of 3a₁Acts on the upper surface of the diaphragm 21.
Is the operating pressure P of the pressure chamber 20._L(Primary pressure when valve is closed
P ₁) Works. Also, on the bottom surface of the diaphragm 21,
Primary pressure P of the flow-side channel 3a ₁Works.

[0039] Thus, when the operating pressure P _L of the pressure chamber 20 is equal to the primary pressure P _1, the operating pressure of the pressure chamber 20 P _L
And the primary pressure P ₁ of the upstream side flow path 3a becomes smaller, the valve body 5 is pressed downward by the operating pressure P _L and the pressing force of the spring 25, and the piston 12 is seated on the valve seat 4. .
That is, the valve body 5 is closed and the flow path 3 is shut off.

When the amount of gas used on the downstream side increases, the secondary pressure P ₂ becomes lower than the set pressure P ₀ .

In this way, the secondary pressure P ₂ is the set pressure P _0.
Upper chamber 33c of pilot valve 33 due to lowering
Since the internal pressure decreases, the diaphragms 33a, 33b
Is displaced upwards. As a result, the diaphragm 33a of the pilot valve 33 is separated from the nozzle 33f. A throttle 36 is provided in the primary pressure supply line 31.
The throttle area ratio is set to be larger than the throttle area ratio of the variable throttle 39 arranged in the operating pressure supply conduit 34.

Therefore, by opening the valve of the nozzle 33f, the gas in the pressure chamber 20 passes through the variable throttle 39 of the working pressure supply pipe 34 and the secondary pressure supply pipe 40 and flows out to the inner chamber 33d of the pilot valve 33. . Further, the gas in the inner chamber 33d flows out to the downstream pipe 7 via the bleed pipe 32.

Therefore, the operating pressure P _L of the pressure chamber 20 is 2
The pressure is reduced to the next pressure P ₂ . As a result, as shown in FIG. 3, the resultant force of the operating pressure P _L and the pressing force of the spring 25 becomes smaller than the pressing force of the primary pressure P ₁ of the upstream side flow path 3a. That is, the operating pressure P _L of the pressure chamber 20 and the upstream flow path 3a
The differential pressure from the primary pressure P ₁ increases, the valve body 5 moves upward, and the piston 12 separates from the valve seat 4.

Since the cylindrical cage 13 is attached to the lower portion of the valve body 5, the valve body 5 is displaced in the valve opening direction while the lower cage 13 is guided by the cage guide 11. Therefore, the valve body 5 is not subjected to the swinging vibration of the fluid pressure, is not inclined with respect to the valve seat 4, and stably opens the valve.

Since the cage 13 is provided with the trapezoidal opening 13a as described above, even if the valve body 5 is separated from the valve seat 4, the opening area does not increase rapidly, and the downstream side is not increased. Will gradually increase. That is, it is possible to change the capacitance or the characteristic by the shape of the opening 13a provided in the cage 13. Therefore, when the valve starts to open, the rate of increase in flow rate is suppressed to a small value, and the valve body 5 is kept for a certain distance or longer.
The rate of increase in the flow rate can be made to increase with increasing.

Further, by the valve opening operation of the valve body 5, the upstream side flow path 3
The fluid from a is rectified by the long hole 11a of the cage guide 11 and the perforated plate 15, and at the same time as the valve opening, the downstream side flow path 3b
It is prevented that it flows vigorously.

Therefore, the valve body 5 is displaced in the valve opening direction, and the flow rate according to the total opening area of the opening 13a that has come out of the valve seat 4 is supplied to the downstream side flow path 3b, and especially the small flow rate. Control in the range is stable. Therefore, the inconvenience that the flow rate rapidly increases during the valve opening operation of the valve element 5 and the small flow rate region cannot be controlled is solved. Therefore, the secondary pressure P ₂ gradually rises, and the occurrence of hunting is prevented.

When the amount of gas used on the downstream side decreases,
The secondary pressure P ₂ rises above the set pressure P ₀ , and the pressure is supplied to the upper chamber 33c of the pilot valve 33 via the detection conduit 35. Diaphragm 3 due to pressure rise in upper chamber 33c
3a moves downward, and the amount of outflow from the nozzle 33f is reduced. As a result, the primary pressure P ₁ from the primary pressure supply pipeline 31 is supplied to the pressure chamber 20 via the check valve 37 and the variable throttle 39 arranged in the operating pressure introduction pipeline 31.

As a result, since the pressure in the pressure chamber 20 rises, the differential pressure between the working pressure P _L of the pressure chamber 20 and the primary pressure P ₁ of the upstream flow passage 3a becomes small, and the valve body 5 is closed. Directional displacement reduces the flow rate to the downstream side. During the valve closing operation, the primary pressure P ₁ is supplied to the pressure chamber 20 via the check valve 37 and the variable throttle 39. Therefore, the valve closing operation should be performed in a shorter time than the valve opening operation described above. You can

[0050] In this way, the pressure control valve 1, the secondary pressure P 2 primary pressure P ₂ is the set pressure P ₀ by displacing the valve body 5 in the valve opening direction or the valve closing direction in accordance with the variation of ₂ Control to be.

The operation when the diaphragm 21 is damaged will be described.

For example, when a part of the diaphragm 21 is broken, the gas having the primary pressure P _{1 in} the upstream flow path 3a flows into the pressure chamber 20 from the damaged portion. Therefore, the operating pressure P _L of the pressure chamber 20 increases and becomes equal to the primary pressure P ₁ before long, and the differential pressure becomes zero. Therefore, the upstream side flow path 3a and the pressure chamber 20 have the same pressure, and the valve body 5 is moved downward by the pressing force of the spring 25 and is displaced to the valve closed state in which the valve body 5 contacts the valve seat 4.

Further, as described above, when the amount of gas used on the downstream side increases, the secondary pressure P ₂ decreases and the pressure in the upper chamber 33c of the pilot valve 33 also decreases, so that the diaphragms 33a and 33b are It is displaced upward and the nozzle 33f is opened. Accordingly, the pressure chamber 20 is opened by opening the valve of the nozzle 33f.
Of the gas is variable throttles 39 and 2 in the working pressure supply line 34.
The gas in the middle chamber 33d passes through the next pressure supply pipe 40 and flows into the middle chamber 33d of the pilot valve 33, and the gas in the middle chamber 33d is bleed pipe 3
It flows out to the downstream side pipe 7 via 2.

However, since the check valve 37 and the variable throttle 39 are arranged in the operating pressure introducing pipe 34, even if the secondary pressure P ₂ of the downstream side pipe 7 is reduced, the gas in the pressure chamber 20 is reduced. The outflow amount is throttled by the variable throttle 39. Therefore, the pressure chamber 20 moves from the damaged portion of the diaphragm 21 to the upstream side flow path 3
When the primary pressure P _{1 of “a”} is supplied to the pressure chamber 20, the operating pressure P _L rises and eventually becomes equal to the primary pressure P ₁ . Therefore, the upstream side flow path 3a and the pressure chamber 20 have the same pressure, and the valve body 5 is moved downward by the pressing force of the spring 25 and is displaced to the valve closed state in which the valve body 5 contacts the valve seat 4.

In this way, when the diaphragm 21 is damaged, it is possible to prevent the inconvenience that the valve body 5 does not close without pressure control.

FIG. 4 shows a second embodiment of the present invention.

In the figure, the check valve 37 and the variable throttle 39 are shown.
Instead of providing the operating pressure introducing line 31, the variable throttle 4
3 is arranged in the secondary pressure supply line 40. Therefore, when the secondary pressure P ₂ is equal to or higher than the set pressure P ₀ , the nozzle 33f of the pilot valve 33 is closed, and the primary pressure P ₁ from the primary pressure supply pipeline 31 passes through the working pressure introducing pipeline 34. It is supplied to the pressure chamber 20. When the secondary pressure P ₂ is less than or equal to the set pressure P ₀ , the nozzle 33f of the pilot valve 33 is opened, and the gas in the pressure chamber 20 passes through the variable throttle 43 and flows into the inner chamber 33d of the pilot valve 33. , Inner chamber 33d
The gas therein flows out to the downstream side pipe 7 via the bleed pipe 32.

However, since the variable throttle 43 is arranged in the secondary pressure supply pipe 40, even if the secondary pressure P ₂ of the downstream side pipe 7 decreases, the amount of gas flowing out from the pressure chamber 20 does not change. It is narrowed down by the variable diaphragm 43. Therefore, the diaphragm 2
Even if 1 is damaged, the pressure chamber 2 is the same as in the first embodiment described above.
0 indicates the upstream side flow path 3a from the damaged portion of the diaphragm 21.
Since the primary pressure P ₁ is supplied to the pressure chamber 20, the operating pressure P _L is increased and eventually becomes equal to the primary pressure P ₁ . Therefore, the upstream side flow path 3a and the pressure chamber 20 have the same pressure, and the valve body 5 is moved downward by the pressing force of the spring 25 and is displaced to the valve closed state in which the valve body 5 contacts the valve seat 4.

FIG. 5 shows a third embodiment of the present invention.

In the figure, the other end of the primary pressure supply conduit 31 is directly connected to the pressure introducing hole 18a of the lid 18. The other end of the secondary pressure supply conduit 40 is directly connected to the pressure introducing hole 18b of the lid 18. Therefore, the operating pressure introducing pipe 34 is not provided and the secondary pressure supply pipe 4 is provided.
At 0, a variable diaphragm 44 is arranged.

Also in the configuration shown in FIG. 5, the first and second embodiments
Secondary pressure P₂Is the set pressure P ₀When above
The nozzle 33f of the lot valve 33 is closed, and the primary pressure is supplied.
Primary pressure P from pipeline 31₁Is the working pressure introducing line 34
It is supplied to the pressure chamber 20 via. Also, the secondary pressure P₂Set up
Constant pressure P₀In the following cases, the nozzle 33 of the pilot valve 33
f is opened, and the gas in the pressure chamber 20 passes through the variable throttle 44.
Overflowing into the inner chamber 33d of the pilot valve 33,
The gas in 3d passes through the bleed pipe 32 to the downstream pipe 7
Spill to.

However, since the variable throttle 44 is disposed in the secondary pressure supply pipe 40, even if the secondary pressure P ₂ of the downstream side pipe 7 decreases, the amount of gas flowing out from the pressure chamber 20 does not change. It is narrowed down by the variable diaphragm 43. Therefore, the diaphragm 2
Even if the pressure chamber 20 is damaged, the pressure chamber 20 will have the same primary pressure P ₁ of the upstream flow passage 3a from the damaged region of the diaphragm 21 as the pressure chamber 20.
As a result, the working pressure P _L rises and eventually becomes equal to the primary pressure P ₁ . Therefore, the upstream side flow path 3a and the pressure chamber 20 have the same pressure, and the valve body 5 is moved downward by the pressing force of the spring 25 and is displaced to the valve closed state in which the valve body 5 contacts the valve seat 4.

In the above embodiment, the pressure of gas is controlled, but the pressure of gas or liquid other than gas may be controlled.

[0064]

As described above, the pressure control valve according to the present invention reduces the flow rate of the fluid flowing from the pressure chamber to the pilot valve in the secondary pressure supply system passage connecting the pilot valve and the pressure chamber. The amount of outflow from the pressure chamber can be reduced by providing the diaphragm of (3) .For example, when the diaphragm is damaged, the inflow from the damaged part becomes larger than the outflow, so the diaphragm and valve body are closed. It can be operated. Therefore, there is a feature that the inconvenience that the valve body cannot be closed while the secondary pressure cannot be controlled to the set pressure can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a pressure control valve according to the present invention.

FIG. 2 is an enlarged vertical cross-sectional view showing the inside of a pressure control valve.

FIG. 3 is a schematic configuration diagram for explaining a valve closing operation of a diaphragm.

FIG. 4 is a schematic configuration diagram of a second embodiment of the pressure control valve according to the present invention.

FIG. 5 is a schematic configuration diagram of a third embodiment of the pressure control valve according to the present invention.

[Explanation of symbols]

 1 Pressure Control Valve 2 Valve Body 3 Flow Path 4 Valve Seat 5 Valve Body 11 Cage Guide 12 Piston 13 Cage 15 Perforated Plate 18 Lid 20 Pressure Chamber 21 Diaphragm 30 Pressure Control Section 31 Primary Pressure Supply Pipeline 32 Bleed Pipeline 33 Pilot Valve 34 Working pressure introduction line 35 Detection line 36 Throttle 37 Check valve 38 Bypass line 39, 43, 44 Variable throttle 40 Secondary pressure supply line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Komiya 4-1-2 Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka Gas Co., Ltd. (72) Inventor Akio Ishii 1-6 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 3 In Tokiko Co., Ltd. (72) Inventor Moriatsu Kobayashi 1-6-3 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Tokiko Co., Ltd. (72) Yasuo Ozawa 1-6 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 3 Tokico Corporation

Claims (1)

[Claims] 1. A valve main body whose flow passage is partitioned into an upstream flow passage and a downstream flow passage by a valve seat, and a space in the valve main body is defined by the upstream flow passage and a pressure chamber,
When the differential pressure between the operating pressure of the pressure chamber and the primary pressure of the upstream flow passage is small, the valve body is driven in the valve closing direction in which it abuts against the valve seat, and when the differential pressure is large, the valve body is A diaphragm that is driven in a valve opening direction away from the valve seat, a primary pressure supply system line that supplies upstream primary pressure to the pressure chamber, and a secondary that supplies downstream secondary pressure to the pressure chamber. A pressure supply system passage, a first throttle provided in the primary pressure supply system passage for reducing a flow rate supplied to the pressure chamber, and a secondary pressure downstream of the valve body becomes equal to or higher than a set pressure. The fluid in the secondary pressure supply system passage is made to flow downstream of the valve main body to lower the operating pressure in the pressure chamber, and when the secondary pressure is equal to or lower than a set pressure, the fluid in the primary pressure supply system passage is made to flow in the valve. Pilot that raises the operating pressure of the pressure chamber by blocking outflow to the downstream of the main body A pressure control valve comprising: a valve; and a second throttle, which is disposed in the secondary pressure supply system passage and reduces the flow rate of the fluid flowing from the pressure chamber to the pilot valve.