JPH0616178Y2 - Flow control valve - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to an improvement of a flow control valve for controlling the flow rate of a fluid such as gas, and in particular, it has no valve body sliding portion and smoothly opens and closes the main valve without being affected by the primary pressure of the fluid passage. The present invention relates to a flow control valve to be obtained.

[Prior art]

FIG. 5 is a longitudinal sectional view of a solenoid valve disclosed in Japanese Utility Model Publication No. 61-13819 as a conventional example. In the figure, reference numeral 1 is a valve body serving as a valve body. The fluid inflow passage 2 on the side and the fluid outflow passage 4 on the secondary pressure side, which is connected to the fluid inflow passage 2 on the side, are formed separately. A valve seat 3a is provided on the partition wall forming the valve port 3, and a valve support 5 standing upright from the center of the valve port 3 to the fluid inflow passage 2 side is integrally formed. A ring body 6 is integrally formed on the upper end of the valve support body 5, and an O-ring 7 is provided on the outer peripheral surface of the ring body 6. Further, a cylindrical valve body 8 which is in sliding contact with the O-ring 7 is fitted and supported on the ring body 6, and a primary pressure chamber 9 is formed in the upper portion of the valve body 8 by the ring body 6. Has been done. The primary pressure chamber 9 is connected to the inside of the fluid inflow passage 2 through a pressure introducing hole 10 and a strainer 11 provided on the upper peripheral wall of the valve body 8. Then, the cylindrical inner diameter (D) of the valve body 8 and the effective valve diameter (d)
And are evenly formed. The valve body 8 is integrally connected to the plunger 12, and is biased by the spring 13 in the direction of closing the valve opening 3. A solenoid (electromagnetic coil) 14 for opening and closing the valve body 8 via the plunger 12 is arranged around the plunger 12. Next, the operation will be described. When the electromagnetic coil 14 is not excited, the valve body 8 is pressed by the spring 13 to close the valve opening 3, and when the electromagnetic coil 14 is excited, the plunger 1
As 2 moves upward against the spring 13,
The valve body 8 rises integrally with the plunger 12 to open the valve opening 3. In the closed state of the valve body 8, the primary pressure P ₁ in the fluid inflow passage 2 acts on the entire outer surface of the valve body 8, while part of the primary pressure P ₁ is in the strainer 11 and the pressure introducing chamber 10. Flow into the primary pressure chamber 9 via. As a result, the downward pressing force P in the valve closing direction is applied to the valve body 8.
₁ and the upward pressing force P ₁ S in the valve opening direction in the primary pressure chamber 9 (where S is the pressure acting area in the valve body 8) act. Here, the cylinder inner diameter (D) of the valve body 8 and the effective valve diameter (d)
And are even, the downward pressing force P ₁ and the upward pressing force P ₁ S are equalized and offset. Further, the secondary pressure P ₂ S on the fluid outflow passage 4 side acts on the lower portion inside the valve body 8, and the upward pressing force by the secondary pressure P ₂ S is applied to the bottom wall of the ring body 6. Since it does not act on the valve body 8 by acting, it can be almost ignored as the opening / closing resistance of the valve body 8. Therefore, the valve body 8 has a primary pressure P in the fluid inflow passage 2.
_{Even if 1} fluctuates, it is opened and closed without being affected by it. FIG. 6 shows the applicant's prior application, Japanese Utility Model Application No. Sho 61-13941.
5 is a vertical cross-sectional view of the valve structure described in the specification No. 5, in which reference numeral 15 is a housing attached to the valve box 1 in the fluid outflow passage 4, in which the plunger 12 is attached. A diaphragm piston 16 integrally connected to the lower end is housed. Between the outer peripheral surface of the diaphragm piston 16 and the inner peripheral surface of the housing 15, a flexible diaphragm (diaphragm) 1 that expands and contracts following the diaphragm piston 16.
7 is stretched. Due to the flexible diaphragm 17 and the diaphragm piston 16, the primary pressure introducing chamber 9 is provided in the housing 15.
The secondary pressure introducing chamber 15a is formed by a partition. The primary pressure introducing chamber 9 is connected to the fluid inflow passage 2 via a pressure introducing pipe 10, and the secondary pressure introducing chamber 15 is connected.
a is a through hole 1 opened at the center of the bottom wall of the housing 15.
It is connected to the fluid outflow passage 4 via 5b. The valve body 8 is integrally connected to the diaphragm piston 16 via a valve shaft 18 that slowly penetrates the through hole 15b. Here, the valve body 8 is formed to have substantially the same cross-sectional area as the diaphragm piston 16 and has a valve seat 8a corresponding to the lower end opening edge of the valve port 3. The valve body 8 is housed in the fluid inflow passage 2 and is biased in the upward direction by the spring 13. Next, the operation will be described. When the electromagnetic coil 14 is de-excited, the valve body 8 is lifted by the urging force of the spring 13 to move to the valve opening 3
Is closed. In this state, the primary pressure P ₁ of the fluid inflow passage 2 flows into the primary pressure introduction chamber 9 through the pressure introduction pipe 10, and the secondary pressure P ₂ of the fluid outflow passage 4 passes through the through hole 15b. Flow into the secondary pressure introducing chamber 15a. At the same time, the primary pressure P ₁ in the fluid inflow passage 2 acts on the upper surface of the valve body 8, and the secondary pressure P ₂ in the fluid outflow passage 4 acts on the lower surface. These primary pressure P ₁ and the secondary pressure P ₂ is equal to the secondary pressure P ₂ of the primary pressure P ₁ and the secondary pressure introduction chamber 15a of the primary pressure introduction chamber 9, Therefore, equilibrium respectively Are offset by equality. As a result, even if the pressures in the fluid outflow passage 2 and the fluid outflow passage 4 fluctuate, the valve body 8 is not affected by this, so that the valve body 8 can be smoothly and reliably opened / closed with a small driving force. To do.

[Problems to be solved by the device]

First, in the conventional solenoid valve shown in FIG. 5, the O-ring 7 serves as the sliding portion of the valve body 8 and the sliding resistance and the starting resistance of the valve body become large. There was a problem that could not be reduced. Moreover, when the solenoid valve is used for a long period of time, the O-ring 7 is worn and deteriorated at an early stage, and a gap is created in the sealing portion by the O-ring 7, so that gas leakage occurs when the solenoid valve is used as a gas valve. There was also a problem that it was very dangerous. Further, since the valve support body 5 is projected from the center of the valve opening 3 toward the center of the valve body 8 and the ring body 6 is integrally formed at the upper end of the valve support body 5, the strength of the valve support body 5 is improved. Is weak, and moreover, the center of the valve support 5 has to be exactly aligned with the center of the plunger 12, which requires machining accuracy, which makes manufacturing difficult and costly. There was also. These problems can be solved by the valve structure of the earlier application shown in FIG. 6, but in the case of this valve structure, the primary pressure fluid such as gas leaks to the secondary side when the diaphragm is damaged. There was a problem that it was leaked out and the safety was impaired. This invention was made in order to solve the above problems. By eliminating the valve body sliding part, the sliding resistance of the valve body
The defects of the rubbing structure of the seal ring due to starting resistance and wear have been improved, and the main valve can be smoothly opened and closed with an extremely small force without being affected by pressure fluctuations, and in the unlikely event of diaphragm damage. Aims to provide a flow control valve capable of reliably preventing leakage of fluid such as gas and maintaining safety.

[Means for Solving the Problems]

A flow control valve according to the present invention includes a main valve that controls opening and closing of a fluid flow path, a diaphragm that follows the main valve and partitions a secondary pressure introducing chamber on the primary pressure acting side of the main valve,
Built in the main valve so that it can be opened and closed by a predetermined stroke in the opening and closing direction, and opens and closes the secondary pressure introduction chamber on the primary pressure acting side of the main valve with respect to the secondary side flow path in the closed state of the main valve. With a safety leak valve to do, by the common valve drive means for driving the safety leak valve and the main valve against the respective return springs, first open the safety leak valve in advance, The main valve is opened.

[Action]

In the flow control valve according to the present invention, the safety leak valve is first opened by a predetermined stroke by the valve drive means. By this valve opening, the secondary pressure introducing chamber on the primary pressure acting side of the main valve communicates with the secondary side flow passage of the main valve, and the secondary pressure is introduced from the secondary side passage into the secondary pressure introducing chamber. The inflow balances the primary side pressure and the secondary side pressure in the closed state of the main valve. In such a pressure balance state, that is, after opening the safety leak valve, the main valve is opened. Therefore, the main valve can be smoothly opened by a small driving force that compresses the return spring without being affected by pressure fluctuations in the fluid passage, and the valve driving means can be designed compactly. Also, in the unlikely event that the diaphragm partitioning the secondary pressure introducing chamber on the primary pressure acting side of the main valve is damaged, the safety leak valve is automatically closed by the return spring and the primary side pressure. Speak. As a result, the pressure on the primary side does not leak to the secondary side, and the safety when the diaphragm is damaged can be reliably maintained.

【Example】

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a vertical cross-sectional view of a flow control valve according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the same part, and the same or corresponding parts as in FIGS. 5 and 6 are designated by the same reference numerals. The duplicate description will be omitted. In the figure, 8 is a main valve for controlling the opening and closing of the valve opening 3, 20 is an auxiliary valve seat integrally incorporated in the central part of the main valve 8, and a plunger is provided in the central part of the auxiliary valve seat 20. A valve shaft 18 integrated with 12 penetrates slidably by a predetermined stroke Sa described later. Reference numeral 21 denotes a secondary pressure distribution hole (sub valve hole) provided in the sub valve seat 20, and 22 denotes a cylindrical area plate which is integrally connected to the main valve 8 and hangs down to the primary pressure side (fluid inflow passage 2). Is a hollow pressure receiving body composed of
A diaphragm 17 is stretched between the lower end peripheral portion of the valve and the peripheral wall of the valve box 1 on the bottom side. This diaphragm 17 has a surface area substantially equal to the effective area where the main valve 8 receives the primary pressure P ₁ , and is adapted to expand and contract following the main valve 8. By the diaphragm 17 and the pressure receiving body 22,
A secondary pressure introducing chamber 15a is formed as a partition on the primary pressure acting side of the main valve 8. The secondary pressure introducing chamber 15a communicates with the secondary side flow passage (fluid outflow passage) 4 of the main valve 8 through the secondary pressure flow hole 21. In the secondary pressure introducing chamber 15a, a safety leak valve (sub valve) 23 for opening and closing the secondary pressure flow hole 21 is integrally connected to the lower end of the valve shaft 18. Further, the valve shaft 18 is integrally provided with an engaging projection 24 that is located above the main valve 8 (sub valve seat body 20) in a separated state when the safety leak valve 23 is closed. . A drive stroke Sa of the valve shaft 18 is set by the engagement protrusion 24, and the stroke Sa causes the safety leak valve 23 to be opened before the main valve 8 is opened. This is a valve opening stroke for communicating the introduction chamber 15a with the secondary side flow path 4. 13a is a return spring for urging the main valve 8 in the valve closing direction,
3b is a return spring for urging the safety leak valve 23 in the closing direction, 25 is a bearing of the valve shaft 18, 26 is a bearing guide (bearing support), and 12a is a fixed core of the electromagnetic coil 14. Next, the operation will be described. When the electromagnetic coil 14 is not excited, the main valve 8 and the safety leak valve 23 are pushed up by the urging forces of the return springs 13a and 13b, and are in the closed state. In such a valve closed state, when the electromagnetic coil 14 is excited, the plunger 12 is lowered so that the valve shaft 18 integrated with the plunger 12 first has a predetermined stroke S.
It descends by a minute. Therefore, the safety leak valve 23 opens prior to the main valve 8 by the stroke Sa. Due to the preceding opening of the safety leak valve 23, the inside of the secondary pressure introducing chamber 15 a communicates with the secondary side flow path 4 via the secondary pressure flow hole 21. As a result, the secondary pressure P ₂ flows from the secondary side flow path 4 into the secondary pressure introducing chamber 15a. In this way, the secondary pressure P ₂ flows into the secondary pressure introducing chamber 15a on the primary pressure acting side of the main valve 8, so that the secondary pressure P ₂
The (internal pressure of the secondary pressure introducing chamber 15a) and the primary pressure P ₁ act on the primary side of the main valve 8, and on the opposite side of the main valve 8, the secondary pressure P ₂ in the secondary side flow passage 4 is provided. Works. Therefore, the main valve 8 is maintained in a pressure balanced state. In this state, the valve shaft 18 further descends by more than the stroke Sa, so that the engaging projection 24 of the valve shaft 18 engages with the upper end of the sub valve seat body 20 and the sub valve seat body 20. At the same time, the main valve 8 is pushed down against the return spring 13a. As a result, the main valve 8 is opened. Such a valve opening operation of the main valve 8 is performed in a state in which the safety leak valve 23 is opened because the engaging protrusion 24 is engaged with the upper end of the auxiliary valve seat body 20 as described above. It is done as it is. For this reason, when the main valve 8 is lowered (opened), the pressure fluid in the secondary pressure introducing chamber 15a flows into the secondary pressure flow hole 2
1 to the secondary side flow path 4. Therefore, the main valve 8 can be smoothly opened without being affected by pressure fluctuation, and the valve opening driving force can be small. In the unlikely event that the diaphragm 17 is damaged, the safety leak valve 23 is closed by the biasing force of the return spring 13b and the primary pressure P ₁ flowing into the secondary pressure introducing chamber 15a. As a result, the primary pressure P ₁ is reduced to the secondary side flow path 4
Safety is maintained without leakage and leakage. FIG. 3 shows another embodiment of the present invention. In this embodiment, a safety leak valve 23 is built in a hollow valve shaft 18 which is integrally formed with the main valve 8 and opens in the central portion of the main valve 8. The above-mentioned safety is secured by a rod 12b of a plunger 12. After opening the leak valve 23 for use against the return spring 13b,
The main valve 8 is opened by the plunger 12 against the return spring 13a, and therefore, in the case of this embodiment, the same operational effect as in the case of the previous embodiment can be obtained. FIG. 4 shows another embodiment. In this example,
A sub valve chamber 18a is formed in a hollow valve shaft 18 integral with the main valve 8, and a safety leak valve 23 integral with the plunger rod 12b is built in the sub valve chamber 18a. By urging the return spring 13b in the downward valve closing direction and raising the plunger 12 against the return spring 13b, first, the safety leak valve 23 is opened,
The main valve 8 is opened by the upward movement of the plunger 12 after the valve is opened. Therefore, also in the case of this embodiment, the same operational effect as in the case of the previous two embodiments can be obtained.

[Effect of device]

As described above, according to this invention, the secondary pressure introducing chamber is formed on the primary pressure acting side of the main valve by the diaphragm that follows the main valve, and the valve body sliding portion is eliminated. The defects of the rubbing structure of the seal ring due to sliding resistance, starting resistance, and wear can be improved, and moreover, the safety leak valve incorporated in the main valve and opened prior to the main valve is used to Since the secondary pressure introducing chamber is communicated with the secondary side flow path of the main valve, the main valve can be maintained in a pressure balanced state, and therefore the main valve is not affected by the pressure fluctuation and has a very small force. Thus, the opening and closing can be smoothly driven, and the valve drive means can be designed compactly. Especially, in this invention, when the diaphragm is damaged, the safety leak valve is automatically closed, so that the fluid such as the gas on the primary side leaks out to the flow passage on the secondary side. Therefore, there is an effect that the safety when the diaphragm is broken can be surely maintained.

[Brief description of drawings]

FIG. 1 is a sectional view of a flow control valve according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the same part, and FIG. 3 is a sectional view of a main part of a flow control valve according to another embodiment. FIG. 5 is a sectional view of a main part of a flow control valve according to still another embodiment, FIG. 5 is a sectional view showing a conventional solenoid valve, and FIG. 6 is a sectional view showing a valve structure of the prior application. In the figure, 4 is a secondary side flow path, 8 is a main valve, 13a, 13b
Is a return spring, 14 is a valve driving means, 15a is a secondary pressure introducing chamber, 17 is a diaphragm, and 23 is a safety leak valve. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. A main valve for controlling opening and closing of a fluid flow path, a diaphragm that follows the main valve, a secondary pressure introducing chamber partitioned by the diaphragm on the primary pressure acting side of the main valve, A safety leak valve that is incorporated in the main valve and opens and closes the secondary pressure introduction chamber with respect to the secondary side flow path of the main valve, and opens this safety leak valve for a predetermined stroke with the main valve closed. And a return spring for individually urging the main valve and the safety leak valve respectively in the valve closing direction.