JP2001041333A - Check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a check valve capable of passing fluid of low pressure therethrough while preventing a counter-flow. SOLUTION: This check valve has a casing, a diaphragm 25 fixed to the casing at an outer peripheral end thereof, a diaphragm side channel 25d disposed in the diaphragm 25, a valve seat 33 for sealing the diaphragm side channel 25d, a valve seat side channel 30 disposed around the valve seat 33, and an urging means 26 for urging the diaphragm 25 against the valve seat 33. Deformation of the diaphragm 25 causes the diaphragm side channel 25d and the valve seat side channel 30 to be communicated with or isolated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve for allowing a fluid to pass only in one direction.

[0002]

2. Description of the Related Art A conventional check valve is shown in FIG. The check valve 1 shown in the figure permits passage of a fluid flowing from the right and blocks passage of a fluid flowing from the left. Check valve 1
A cylindrical casing 2, a fluid hole 7 provided in the casing 2 through which a fluid passes, a valve body 3 slidably provided in the casing 2 to open and close the fluid hole 7,
A spring for urging the valve body against the fluid hole; The valve body 3 has a cylindrical shape forming the hollow portion 5 and has a fluid hole 7.
Side (entrance side) is closed. A lateral hole 6 communicating with the hollow portion 5 is provided in the side wall. In the closed state, the valve body 3 is urged to the edge of the fluid hole 7 by the spring 4, and at this time, the O-ring 8 for sealing the fluid between the edge of the fluid hole 7 and the valve body 3 3.

In the above check valve, when the fluid pressure on the outlet side is higher than the fluid pressure on the inlet side, the check valve is closed. That is, since the spring 4 urges the valve body 3 toward the edge of the fluid hole 7, the backflow of the fluid from the outlet side to the inlet side is prevented. The fluid pressure on the inlet side becomes larger than the fluid pressure on the outlet side, and the fluid pressure on the inlet side slides the valve body 3 toward the outlet side against the urging force of the spring 4, whereby the fluid hole 7 is opened. The fluid flows out to the outlet side through the horizontal hole 6 and the hollow portion 5 of the valve body 3.

[0004]

When the check valve is closed, the spring 4 urges the valve body 3 toward the edge of the fluid hole 7 as described above. Therefore, unless the fluid pressure on the inlet side becomes larger than the urging pressure by the spring 4, the fluid on the inlet side cannot pass through the check valve. That is, in the above-described conventional check valve, even if the fluid pressure on the inlet side is higher than the fluid pressure on the outlet side, the fluid cannot flow unless the difference is large. In order to allow the fluid to flow even with a small pressure difference, a spring having a small elastic force may be employed. However, if the elastic force of the spring 4 is reduced,
The fluid on the outlet side may flow back to the inlet side. For this reason, there has been a problem that a fluid having a small pressure cannot be flown while preventing a backflow of the fluid on the outlet side.

[0005] In view of the above circumstances, an object of the present invention is to provide a check valve capable of passing a fluid having a small pressure while preventing a backflow.

[0006]

In the above-mentioned conventional check valve, the fluid on the inlet side is supplied to the valve body 3 by the opening area of the fluid hole 7.
Is acting on the pressure. If the fluid pressure on the inlet side is applied to a larger area, the biasing force of the spring 4 can be countered with a larger force at the same pressure. The present invention uses this principle. That is, in the check valve of the present invention, a casing, a diaphragm, a diaphragm-side flow passage provided in the diaphragm, a valve seat for sealing the diaphragm-side flow passage, and a valve provided around the valve seat A seat-side flow path and an urging means for urging the diaphragm toward the valve seat are provided, and the diaphragm-side flow path and the valve-seat-side flow path are communicated and separated by deformation of the diaphragm. Specifically, FIG.
As shown in (2), the fluid pressure on the inlet side acts on the diaphragm 25 having a large area through the valve seat side flow path 30. Thereby, a larger force can be applied even at the same pressure. Since the portion indicated by the symbol A is not urged by the urging means 26, the fluid flows into the inside (a slight gap between the diaphragm 25 and the casing 21) due to an increase in the fluid pressure on the inlet side, Pressure can be applied to the diaphragm 25.

Further, in the present invention, the outer peripheral end of the diaphragm is fixed to the casing in order to more effectively apply the fluid pressure on the inlet side. In this state, the diaphragm 25 deforms and moves as shown in FIGS. Since the outer peripheral end 25f of the diaphragm 25 is fixed, the diaphragm 25 can be deformed against the outlet-side fluid pressure with a smaller force around the outer peripheral end portion as a fulcrum. Further, the diaphragm-side flow path may be provided at the center of the diaphragm, and the urging means may urge the periphery of the opening of the diaphragm-side flow path toward the valve seat to seal the valve seat. Specifically, as shown in FIG. 1, a tube 25 a constituting a diaphragm-side flow path 25 d is provided at the center of the diaphragm, and the urging means 26 attaches the tip of the tube 25 a to the O-ring 32 provided on the valve seat 33. Energize.

With this construction, in the present invention, as shown in FIG. 1, when the fluid pressure on the outlet side is large, the diaphragm 25 comes into close contact with the O-ring 32 of the valve seat 33 and the diaphragm Side channel 2
5d is sealed, and the valve seat side flow path 30 and the diaphragm side flow path 25d are separated. When the fluid pressure on the inlet side increases to some extent, the diaphragm 25 is moved to the left in the drawing against the urging means 26, and as shown in FIG.
2, the sealing of the diaphragm-side flow path 25d is released, and the valve-seat-side flow path 30 communicates with the diaphragm-side flow path 25d.

When the diaphragm is a flat plate as shown in FIG. 6, when the diaphragm 25 moves as shown by a broken line, the diaphragm 25 is over-tensioned.
There is a risk of damage. In order to prevent this, a bulging portion is provided in the diaphragm in an annular shape. For example, as shown in FIG. 1, the diaphragm 25 is provided with an annular ridge (bulging portion) 25e bulging to the outlet side. By doing so, FIG.
When deformed from the state shown in FIG. 4 to the state shown in FIG. 4, the ridge 25e is inverted so as to bulge to the opposite side, so that tension is not applied to the diaphragm 25 and breakage is prevented. In the closed state, it is necessary to keep the shape of the diaphragm. That is, if the corresponding casing 21 is flat despite the fact that the diaphragm 25 is provided with a bulging portion as shown in FIG. 7, the diaphragm 25 is unexpectedly shown by a broken line due to the fluid pressure at the outlet side. It may cause deformation and damage. In order to prevent this, as shown in FIG. 1, the inlet housing 21 may be formed so as to correspond to the shape of the diaphragm 25.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the check valve includes a casing including an inlet-side housing 21 and an outlet-side housing 22. The outlet housing 22 has a tubular shape, and accommodates a diaphragm 25 and a spring (biasing member) 26 in a hollow portion thereof. At the ends of the inlet side housing 21 and the outlet side housing 22, thread grooves 21a and 22a for connecting pipes are provided.

As shown in FIGS. 1 and 3, the diaphragm 25 includes a tube portion 25a and a diaphragm main body 25b extending from one end of the tube portion 25a. The pipe part 25a forms a flow path 25d (diaphragm-side flow path), and has a guide part 25c having an enlarged diameter at the other end, and a ridge (bulge) bulging to the outlet side in the diaphragm main body 25b. Part 25e is formed in an annular shape. Further, in accordance with the shape of the diaphragm main body 25b, the corresponding portion of the inlet side housing 21 is formed so as to bulge toward the outlet side.

The inlet housing 21 and the outlet housing 22 are fixed to each other by a nut 23 with the outer peripheral end 25f of the diaphragm main body 25b interposed therebetween. Further, the inlet housing 21, the outlet housing 22, and the outer peripheral end 25 f of the diaphragm main body 25 b are sealed by an O-ring 31. In addition, the diaphragm body 2
With the outer peripheral end 25f of 5b fixed, the diaphragm main body 25b is elastically deformed, and the diaphragm 25 slides in the axial direction.

The spring 26 has one end in contact with a spring receiver 24 provided in the outlet side housing 22 and the other end guided by the guide portion 25c of the tube portion 25a to provide the tube portion 25a in the inlet side housing 21. The valve seat 33 is biased. More specifically, it urges the O-ring 32 fitted to the valve seat 33. Three holes (valve seat side flow paths) 30 are provided around the valve seat 33 in the circumferential direction facing the diaphragm main body 25b. The hole 30 is closed by the diaphragm main body 25b in the closed state. In the open state, the seal between the tube portion 25a and the O-ring 32 is released by sliding the diaphragm 25, and the hole 30 is opened.

In this check valve, when the fluid pressure on the outlet side is higher than the fluid pressure on the inlet side, or when the fluid pressure on the inlet side is larger than the fluid pressure on the outlet side, the difference is small. Then, the check valve is closed. That is,
Since the spring 26 urges the tube portion 25a of the diaphragm 25 toward the valve seat 33, the hole 30 is closed,
Prevents backflow of fluid from the outlet side to the inlet side.

When the fluid pressure on the inlet side is somewhat higher than the fluid pressure on the outlet side, the pipe 25a of the diaphragm 25
Is separated from the O-ring 32, the hole 30 is opened, the check valve is opened, and the fluid flows out from the inlet side to the outlet side. This case will be described in more detail. In the closed state, the hole 30 is closed as described above. At this time, the diaphragm main body 25b receives the pressure of the fluid on the inlet side in the left direction in the drawing. Further, the diaphragm 25 receives the pressure by the fluid on the outlet side and the urging force of the spring 26 in the right direction in the drawing. At this time, the O-ring 3
2, the hole 30 is closed, but the fluid pressure on the inlet side acts on the entire diaphragm main body 25b. That is, since the diaphragm 25 is elastically deformable and the diaphragm main body 25b is not biased by the spring 26, the inlet-side fluid flows between the diaphragm main body 25b and the inlet-side casing 2 shown in the region A of FIG.
1 and can apply pressure to the diaphragm main body 25b.

Considering the case where the fluid pressure on the inlet side is gradually increased, when the pressure becomes larger than the fluid pressure on the outlet side and further becomes larger than the urging force of the spring 26, as shown in FIG. Slides to open the hole 30, and the fluid on the inlet side flows out to the outlet side via the hole 30 and the pipe portion 25a. At this time, comparing the diaphragm 25 of the present embodiment with the conventional check valve of FIG. 5, the conventional check valve receives fluid pressure on the inlet side on the side surface of the valve body 3 through the fluid hole 7. It has become. Then, the entire valve body 3 slides leftward in the drawing. Since the diaphragm 25 of the present embodiment receives pressure by the diaphragm main body 25b, the area for receiving the pressure is large, and the diaphragm 25 can oppose the urging force of the spring 26 even with a slight pressure as compared with a conventional check valve. Further, the outer peripheral end 25f of the diaphragm main body 25b is fixed. Therefore, the outer peripheral end 25
With the principle of leverage using f as a fulcrum, it is possible to easily slide the diaphragm 25 against a pressure of the outlet fluid even with a small pressure. Further, the ridge portion 25e is inverted and swells to the opposite side, so that the diaphragm 25 is easily deformed from the state shown in FIG. 1 to the state shown in FIG. 4 when the diaphragm 25 slides without applying excessive tension to the diaphragm body 25b. Is possible.

As described above, in the check valve according to the present embodiment, the fluid can be passed even if the fluid pressure on the inlet side is small, so that it is not necessary to reduce the elastic force of the spring. Thereby, the backflow of the fluid on the outlet side can also be prevented.

[0018]

As described above, in the present invention, the pressure of the inlet fluid is received by the diaphragm whose outer peripheral end is fixed to the casing. Therefore, even with a small pressure, the valve can be opened while opposing the urging force of the urging means. Since there is no need to reduce the urging force of the urging means, backflow of the fluid on the outlet side can also be prevented.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a check valve shown as one embodiment of the present invention, showing a closed state.

FIG. 2 is an inlet side view of the check valve.

FIG. 3 is a perspective view of a diaphragm used in the check valve.

FIG. 4 is a front sectional view of the check valve, showing an open state.

FIG. 5 is a front sectional view of a conventional check valve.

FIG. 6 is a diagram illustrating the principle of a check valve according to the present invention.

FIG. 7 is a diagram illustrating the principle of a check valve according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Inlet side housing (casing) 22 Outlet side housing (casing) 25 Diaphragm 25b Diaphragm main body 25d Diaphragm side flow path 25f Outer end 26 Spring (biasing means) 30 Hole (valve seat side flow path) 32 O-ring 33 Valve seat

Claims (3)

[Claims] 1. A casing, a diaphragm having an outer peripheral end fixed to the casing,
A diaphragm-side flow passage provided in the diaphragm, a valve seat for sealing the diaphragm-side flow passage, and a valve seat-side flow passage provided around the valve seat;
A check means for urging the diaphragm toward the valve seat, wherein the diaphragm-side flow path and the valve-seat-side flow path are communicated and separated by deformation of the diaphragm. 2. The check valve according to claim 1, wherein the diaphragm-side flow path is provided at a central portion of the diaphragm, and the urging means extends around the opening of the diaphragm-side flow path through the valve seat. A non-return valve characterized by being urged to seal. 3. The check valve according to claim 1, wherein the diaphragm has a bulging portion that bulges annularly.