JPH0413479Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an on-off valve whose opening pressure and closing pressure are approximately equal.

(Prior Art) Fig _{. 3 shows a longitudinal section of an on-off valve, which has a poppet 109 with a projected area A 2 (} >A ₁ ) on a valve seat 105 having a through hole 106 with a cross-sectional area A 1 . If the pressure that the poppet 109 receives on its upper surface exceeds a predetermined value, the poppet 109 will respond to an upward force based on the elastic force of the spring 110 and the pressure acting on the lower surface of the poppet 109. It moves downward against the resistance, and in Fig. 3,
As shown by the chain line, it comes into contact with the stopper 108 and allows the fluid to pass therethrough.

By the way, in order to increase the responsiveness of such an on-off valve and to make the rise of the so-called valve-opening curve steep, the opening area A1 of the opening area _A1 is reduced by constricting the through hole 106, as shown in FIG. , (A ₂ −A ₁ ) may be increased. Then, when the poppet 109 is seated on the valve seat 105 and the valve is closed, the poppet 1
The downward force F ₁ = P ₁ · A ₁ (here, P ₁ is the pressure acting on the top surface of the poppet 109) is received by the top surface of the poppet 109, and once the poppet 109 is pressed against the valve seat 10.
5, the force F ₂ =P ₂ ·A ₂ applied to the upper surface of the poppet 109 increases discontinuously, so the poppet 109 quickly moves downward and the rising curve of the opening/closing valve becomes steeper.

(Problem to be solved by the invention) However, when the through hole 106 is narrowed as described above to increase the value of the area difference (A ₂ - _{A 1} ), the area difference (A ₂ - _{A 1} ) is A problem arises in that hysteresis occurs between the valve opening pressure and the valve closing pressure, and the difference between the two (valve opening pressure - valve closing pressure) becomes large, making it impossible to control the pressure-flow characteristics within a narrow range.

The present invention was developed in view of the above problems, and its purpose is to make the rise of the valve opening curve steeper, and at the same time, to maintain the valve opening pressure and the valve closing pressure approximately equal. An object of the present invention is to provide an on-off valve that can eliminate hysteresis and control pressure-flow characteristics within a narrow range.

(Means for Solving the Problems) In order to achieve the above object, the present invention arranges a valve seat having a through hole and a stopper facing the through hole at a predetermined interval to open and close the through hole. In order to achieve this, a poppet is provided that is movable between the valve seat and the stopper, and a pressure-receiving surface is provided on the through-hole side of the poppet to increase the difference between the area of the pressure-receiving surface and the opening area of the through-hole. At the same time, a pressure chamber communicating with the pressure-receiving surface of the poppet was formed at a position where the poppet and the stopper come into contact when the valve is opened.

(Function) Therefore, when the poppet moves between the valve seat and the stopper to open and close the through hole, the pressure receiving area of the pressure acting on the pressure receiving surface of the poppet when the valve is opened is from the through hole to the pressure receiving surface when the valve is closed. Since the area is considerably larger than the pressure receiving area of the pressure acting on the on-off valve, the opening curve of the on-off valve has a steep rise, and its responsiveness is enhanced.

Further, when the valve is opened, the pressure acting on the pressure receiving surface of the poppet is also transmitted to the pressure chamber, and the pressure in the pressure chamber becomes equal to the pressure acting on the pressure receiving surface. Therefore, when the valve is closed, the pressure acting on the pressure receiving surface by the area occupied by the pressure chamber is canceled out, and the differential pressure becomes the pressure when the valve is closed. Therefore, as a result, it is possible to maintain the valve opening pressure and the valve closing pressure substantially equal, and to control the pressure-flow characteristics of the on-off valve within a narrow range.

(Example) An example of the present invention will be described below based on the accompanying drawings.

1 and 2 are longitudinal sectional views of the on-off valve according to the present invention, with FIG. 1 showing the valve in the closed state and FIG. 2 showing the valve in the open state, respectively.

First, the structure of the on-off valve 1 will be explained based on FIG. A screw member 4 is screwed into the valve seat 4, and a valve seat 5 made of an elastic material is fixed to the lower part of the screw member 4. A through hole 6 is provided in the center of the screw member 4 and the valve seat 5.

A stopper holding member 7 is fixed to the lower inner peripheral portion of the case 3, and a stopper 8 formed of an elastic material is attached and held to the top of the stopper holding member 7. Note that a through hole 7a is formed in the lower flange portion of the stopper holding member 7.

A generally disk-shaped poppet 9 is seated on the lower surface of the valve seat 5 by a spring 10. Incidentally, the area (projected area) A ₂ of the pressure receiving surface 9a provided on the side of the through hole 6, that is, the pressure receiving area A ₂ of the poppet 9 when the valve is open, is equal to the opening area A ₁ of the through hole 6, that is, the poppet when the valve is closed. It is set considerably larger than the pressure receiving area of No. 9 (A ₂ >>A ₁ ).

Incidentally, a pressure chamber 11 is formed at the contact portion between the poppet 9 and the stopper 8 when the valve is opened as shown in FIG. 2, and is maintained at the same pressure as the pressure on the upper surface of the poppet 9. The pressure chamber 11 is constructed by forming a recess 8a on the upper surface of the stopper 8 and drilling a through hole 9a in the poppet 9 to open into the recess 8a. Here, the opening area of the recess 8a is defined as _A3 .

Next, the operation of the on-off valve 1 will be explained.

The pressure P ₁ acting on the area A ₁ of the upper surface of the poppet 9 is small, and the force based on this pressure P ₁ (=P ₁・
A ₁ ) is the force based on the elastic force of the spring 10 and the pressure P ₂ acting on the lower surface of the poppet 9 (=P ₂ · A ₂ )
, the poppet 9 is seated on the valve seat 5 as shown in FIG. 1, and the flow of fluid in the flow path 2 is blocked.

Therefore, if the force based on the pressure _P1 that the poppet 9 receives on its upper surface when the valve is closed increases beyond the sum of the elastic force of the spring 10 and the force based on the pressure P2 acting on the lower surface of the poppet 9, the poppet 9 is valve seat 5
However, at this moment, the pressure-receiving area of the poppet 9 increases rapidly from _A1 to _A2 , and the poppet 9 receives a large downward force on its upper surface, and quickly seats on the stopper 8 as shown in FIG. , the rise of the opening curve of the on-off valve 1 becomes steeper, and its responsiveness is enhanced. At this time, the on-off valve 1 is in the open state, and the fluid in the flow path 2 flows from the upstream side of the on-off valve 1 to the through hole 6 and poppet 9 of the on-off valve 1, as shown by the arrow in FIG.
It flows to the downstream side of the on-off valve 1 through the space between the inner peripheral wall of the case 3 and the through hole 7a. In addition, in this valve open state, the pressure chamber 11 is formed at the contact portion between the poppet 9 and the stopper 8, as shown in FIG. It is communicated with the upper surface side of the poppet 9 through the hole 9a, and the internal pressure of the recess 8a is transferred to the poppet 9.
is equal to the pressure P ₁ acting on the top surface of . As a result, the vertical force acting on the opening area _A3 of the recess 8a on the upper and lower surfaces of the poppet 9 is canceled out.
In the end, the force acting on the upper and lower surfaces of the poppet 9 is only the ring-shaped portion of area (A ₂ - A ₃ ), and the poppet 9 has pressures P ₁ and P ₂ acting on these upper and lower surfaces.
_The force ₍ =ΔP×(A ₂ −
A ₃ )) comes into play. The differential pressure ΔP at this time is generated due to pressure loss due to fluid flow, vortex loss on the lower surface side of the poppet 9, and the like.

Here, the poppet 9 is opened from the closed state shown in FIG.
The valve opening pressure required to open the valve is compared with the value of the valve closing pressure required to close the poppet 9 from the valve open state shown in FIG. Pressure receiving area A ₁ on the top surface of poppet 9 when the valve is closed
is small as a result of constricting the through hole 6, and the actual pressure receiving area of the upper surface of the poppet 9 when the valve is open is (A ₂ − A ₃ ), which is small, so the pressure receiving area A ₁ when the valve is open and closed is ，
If (A ₂ − _{A 3} ) is adjusted appropriately by taking into account the elastic force of the spring 10, it becomes possible to set the valve opening pressure and the valve closing pressure approximately equal to eliminate the hysteresis between the two. The pressure-flow characteristics of the on-off valve 1 can be controlled within a narrow range.

(Effect of the invention) As is clear from the above explanation, according to the invention, when the poppet is moved to open and close the through hole, the pressure receiving area of the pressure acting on the pressure receiving surface of the poppet when the valve is opened is equal to the pressure receiving area of the poppet when the valve is closed. Since the area is considerably larger than the pressure receiving area of the pressure acting on the on-off valve, the opening curve of the on-off valve has a steep rise, and its responsiveness is enhanced.

Further, when the valve is opened, the pressure acting on the pressure receiving surface of the poppet is also transmitted to the pressure chamber, and the pressure in the pressure chamber becomes equal to the pressure acting on the pressure receiving surface. Therefore, when the valve is closed, the pressure acting on the pressure receiving surface by the area occupied by the pressure chamber is canceled out, and the differential pressure becomes the pressure when the valve is closed. Therefore, it is possible to maintain the valve opening pressure and the valve closing pressure substantially equal to eliminate hysteresis therebetween, and to control the pressure-flow characteristics within a narrow range.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing the on-off valve according to the present invention in the closed state, Fig. 2 is a longitudinal sectional view showing the on-off valve in the open state, and Fig. 3 is a longitudinal sectional view of the conventional on-off valve. be. Explanation of symbols, 1... Open/close valve, 8... Stopper,
8a... recess, 9... poppet, 9a... through hole,
11...Pressure chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A valve seat having a through hole and a stopper facing the through hole are arranged at a predetermined interval, and the valve seat and the stopper are arranged to open and close the through hole. The poppet is provided with a pressure-receiving surface on the side of the through hole, and the difference between the area of the pressure-receiving surface and the opening area of the through hole is set to be large, and the poppet An on-off valve characterized in that a pressure chamber communicating with a pressure-receiving surface of a poppet is formed at a position where it contacts a stopper. (2) The scope of the utility model registration claim, characterized in that the pressure chamber is constructed by forming a recess in the contact surface of the stopper with the poppet, and drilling a through hole in the poppet that opens into the recess. The on-off valve described in paragraph 1.