JP7575771B2 - Check valve and fluid supply system - Google Patents

Description

The present invention relates to a check valve, and more specifically to a check valve that is attached to a positive pressure space and opens when a fluid is supplied as the pressure in the space drops, and a fluid supply system that uses this check valve.

In general, a check valve that restricts the flow of a fluid in one direction (see, for example, Patent Document 1) is used in a system in which a valve element that abuts against and separates from a valve seat is pressed against the valve seat by a biasing means that biases the valve element toward the valve seat to prevent the flow of fluid from the secondary side, while allowing a fluid from the primary side with a pressure greater than the pressing force of the biasing means to flow to the secondary side.

The check valve described above can also be used when it is necessary to prevent leakage of fluid from a secondary system under positive pressure to the outside (primary side) and when it is necessary to supply fluid from the primary side to the secondary side when the pressure on the secondary side falls below a specified value.

JP 2015-183828 A

However, this type of usage requires that a certain pressure (the reduced secondary pressure plus a pressure equal to or greater than the pressure generated by the biasing means) be constantly maintained on the primary side.

If the secondary side cannot maintain a specified pressure, it is possible to detect the pressure on the secondary side, and when the pressure on the secondary side falls below a specified value, open an on-off valve arranged on the primary side of the check valve to supply fluid at a specified pressure to the secondary side. However, in this case, the valve disc is pressed toward the valve seat by the biasing means, which can cause the valve disc to vibrate slightly (chatter), resulting in vibration and noise and damage to the valve disc. In addition, even a slight increase in pressure on the secondary side can cause the valve disc to sit on the valve seat, preventing a sufficient supply of fluid from the primary side.

The present invention was made in consideration of these points, and its purpose is to provide a check valve and fluid supply system that can stably supply fluid from the primary side without the valve body vibrating slightly when the secondary side pressure falls below a predetermined value, and that will not close even if the secondary side pressure rises slightly.

The check valve according to the present invention, which has been made to solve the above problems,
a cylindrical first main body having a valve chamber and a first flow passage formed therein, and a valve seat formed at an end of the first flow passage on the valve chamber side;
a cylindrical second body having an accommodation space for accommodating the valve chamber side of the first body and a second flow path formed therein,
A valve body that comes into contact with and separates from the valve seat portion and a biasing means that biases the valve body toward the second flow passage are disposed in the valve chamber.

This check valve is designed to bias the valve body to the secondary side by a biasing means with a biasing force smaller than the biasing force from the positive pressure secondary side connected to the second flow path, so that the valve body normally abuts against the valve seat portion, preventing the flow of fluid between the primary and secondary sides, and the biasing means separates the valve body from the valve seat portion. The biasing force of the biasing means keeps the valve body in a stable state and does not cause micro-vibrations.

In this case, the valve body is cylindrical with a bottom, has a seat portion at its tip, which serves as the bottom, that abuts against the valve seat, the outer circumferential surface of the rear end is in sliding contact with the valve chamber, and has an opening between the tip and rear end that communicates with the interior.

In addition, a fluid supply system according to the present invention, which is made to solve the same problem, is
The check valve as described above;
an on-off valve disposed in a flow path that communicates the first flow path with a primary system;
a pressure measuring means disposed in a secondary system connected to the second flow path;
a control device to which the measured value of the pressure measuring means is input and which opens and closes the on-off valve,
The control device opens the on-off valve when the pressure value measured by the pressure measuring means falls below a threshold value, and supplies fluid from the primary system to the secondary system.

The check valve and fluid supply system according to the present invention can provide a check valve and fluid supply system that can stably supply fluid from the primary side without the valve body vibrating when the pressure on the secondary side falls below a predetermined value.

FIG. 2 is a front cross-sectional view showing a check valve according to the present invention in a closed state. FIG. 4 is a front cross-sectional view showing the check valve in an open state. 5A and 5B are cross-sectional views for explaining the assembly procedure of the check valve, in which FIG. 5A shows the check valve before assembly and FIG. 1 is a schematic diagram illustrating a fluid supply system of the present invention;

The following describes preferred embodiments of the check valve and fluid supply system according to the present invention with reference to the drawings. Unless otherwise specified, the shapes of the components and their relative positions described in the examples are merely illustrative examples and are not intended to limit the scope of the invention. In addition, for convenience, the directions of components, etc. may be referred to as up, down, left, and right depending on the direction on the drawings, but these do not limit the scope of the present invention.

<Embodiment 1>
A check valve 1 according to the present invention is shown in FIGS.

[non-return valve]
The check valve 1 of the present invention comprises a cylindrical first body 2 which defines a valve chamber 20 and a first flow path 21 therein and which defines a valve seat portion 2a at the valve chamber 20 side end of the first flow path 21, and a cylindrical second body 3 which defines an accommodation space 30 for accommodating the valve chamber 20 side of the first body 2 and a second flow path 31 therein, and within the valve chamber 20 there is provided a valve element 4 which abuts and separates from the valve seat portion 2a, and a biasing means 5 which biases the valve element 4 towards the second flow path 31.

The valve body 4 is cylindrical with a bottom, and has a truncated cone-shaped seat portion 4a at its tip end 42, which serves as the bottom, that abuts against the valve seat portion 2a. The outer peripheral surface of the rear end 43 is in sliding contact with the inner peripheral surface of the valve chamber 20. Between the tip end 42 and the rear end 43, there is an opening 41 that communicates with the internal flow path 40 of the valve body 4.

[First body]
The first body 2 has a cylindrical shape in which a valve chamber 20 in which the valve body 4 and the biasing means 5 are disposed and a first flow passage 21 having a diameter smaller than the inner diameter of the valve chamber 20 are connected. The end of the first flow passage 21 on the valve chamber 20 side forms a truncated cone-shaped valve seat portion 2a, and the other end forms a connecting portion that is connected to a pipe that forms the flow passage. The angle that the peripheral surface of the truncated cone portion that forms the valve seat portion 2a forms with the central axis is set to be slightly larger than the angle that the peripheral surface of the truncated cone portion of the seat portion 4a of the valve body 5 forms with the central axis.

The valve chamber 20 of the first body 2 contains the valve body 4 and the biasing means 5. As described above, the outer diameter of the rear end 43 of the valve body 4 is slightly smaller than the inner diameter of the valve chamber 20, and the tip end 42 has an even smaller diameter. In the open state, an annular gap is formed between the rear end 43 and the inner surface of the valve chamber 20, forming a flow path through which the fluid from the primary side flows.

The biasing means 5 uses a coil spring whose both ends abut against the annular bottom surface 2b on the first flow path 21 side of the valve chamber 20 and the annular portion 43a which is the step between the rear end 43 and the tip end 42 of the valve body 4. The pressing force of the coil spring is set to be smaller than the pressing force which biases the valve body 4 towards the valve seat portion 2a by the pressure of the secondary fluid. In this embodiment, an intermediate portion is provided between the tip end 42 and the rear end 43, whose outer diameter is intermediate between the outer diameter of the tip end 42 and the rear end 43. The outer diameter of this intermediate portion is approximately the same as the inner diameter of the coil spring used, allowing the coil spring to be stably arranged.

[Second Body]
The second body 3 has a storage space 30 that accommodates the valve chamber 20 side of the first body 2, and a second flow path 31. The second flow path 31 has a smaller diameter than the inner diameter of the storage space 30. When the valve body 5 is in an open state, the end face of the rear end portion 43 of the valve body 5 abuts against the annular bottom surface 3a of the storage space 30 due to the biasing force of the biasing means 5.

The valve chamber 20 side of the first body 2 is accommodated in the accommodation space 30 of the second body 3. There is no particular limitation on the joining of the first body 2 and the second body 3, but in this embodiment, the joining is performed by screwing the male threaded portion 22 formed on the outer peripheral surface of the first body 2 into the female threaded portion 32 formed on the inner peripheral surface of the accommodation space 30 of the second body 3.

Assembling the check valve 1, as shown in Figure 3, the coil spring as the biasing means 5 and the valve body 4 are placed on the first body 2 (see Figure 3(a)). At this time, the open end of the valve body 4 protrudes from the valve chamber 20 side end of the first body 2. After that, the second body 3 is screwed in (see Figure 3(b)). By screwing in the valve chamber 20 side end of the first body 2 until it abuts against the annular bottom surface 3a of the second body 3, the open end of the valve body 4 is flush with the valve chamber 20 side end of the first body 2 and the annular bottom surface 3a of the second body 3.

In this state, the second flow path 31 is connected to the positive pressure secondary side, and the first flow path 21 is connected to a source of fluid to be supplied when the secondary side falls below a predetermined pressure.

<Embodiment 2>
FIG. 4 shows a fluid supply system S according to the present invention.

[Fluid Supply System]
The fluid supply system S of the present invention comprises the check valve 1 of embodiment 1, an on-off valve V arranged in a flow path 13 connecting a first flow path 21 of the check valve 1 with a primary side system 11, a pressure measurement means P provided in a secondary side system 12 connected to a second flow path 31 of the check valve 1, and a control device 10 which receives the measurement value of the pressure measurement means P and issues instructions to open and close the on-off valve V, and which opens the on-off valve V when the pressure value measured by the pressure detection means P falls below a threshold value, thereby supplying fluid from the primary side system 11 to the secondary side system 12.

The primary system 11 is not particularly limited, and an accumulator or tank that stores the fluid required when the pressure in the secondary system 12 drops at a certain pressure can be used. When using a tank, a pump that sends the fluid to the secondary side is also used.

The secondary system 12 is not particularly limited as long as it is an environment in which a constant pressure is always maintained, and examples include experimental equipment filled with a specified fluid at a constant pressure.

The on-off valve V constantly prevents the fluid stored in the primary system from flowing toward the check valve 1, and it is preferable to use a normally closed solenoid valve.

The control device 10 is not particularly limited, but may be a personal computer or a sequencer, as long as it can apply an open signal to the on-off valve V when the pressure value measured by the pressure detection means P falls below the threshold value.

In the above configuration, in the fluid supply system S, the first flow path 21 of the check valve 1 is attached to the secondary system 12 via the flow path 14 or directly to the secondary system 12, and the second flow path 31 is connected to the primary system via an on-off valve V. As long as the secondary system 12 maintains a constant pressure, no fluid flows from the primary system 11. The flow path 13 connecting the primary system 11 and the first flow path 21 of the check valve 1 is usually maintained at atmospheric pressure.

When the pressure in the secondary system 12 falls below the threshold, the pressure pressing the valve body 4 of the check valve 1 against the valve seat 2a decreases, and the valve body 4 is separated from the valve seat 2a by the biasing force of the biasing means 5. At this time, the control device 10 receives a signal indicating that the pressure value measured by the pressure detection means P has fallen below the threshold and applies an open signal to the on-off valve V, so that the fluid stored in the primary system 11 passes through the open check valve 1 and flows into the secondary system 12.

In the check valve 1, the valve body 4 separates from the valve seat 2a due to a pressure drop in the secondary system 12. However, even if the pressure drop in the secondary system 12 is small and the movement of the valve body 4 is small, the pressure in the first flow path 21 increases due to the flow of fluid from the primary system 11, the valve body 4 moves to the position shown in FIG. 2, and the fluid from the primary system 11 is smoothly supplied to the secondary system 12.

The check valve of the present invention is capable of allowing fluid to flow from the primary side to the secondary side as the pressure on the secondary side drops, and can therefore be suitably used as a key component of a fluid supply system in an environment where it is necessary to supply fluid from the primary system when the pressure in the secondary system falls below a threshold (predetermined pressure).

REFERENCE SIGNS LIST 1 check valve 10 control device 11 primary system 12 secondary system 13 flow path 2 first body 2a valve seat portion 20 valve chamber 21 first flow path 3 second body 30 accommodation space 31 second flow path 4 valve body 5 biasing means (coil spring)
P: Pressure measuring means V: Opening and closing valve

Claims (2)

a cylindrical first main body having a valve chamber and a first flow passage formed therein, and a valve seat formed at an end of the first flow passage on the valve chamber side;
a cylindrical second body having an accommodation space for accommodating the valve chamber side of the first body and a second flow path formed therein,
a check valve including a valve body that is adapted to come into contact with and separate from the valve seat and a biasing means that biases the valve body toward the second flow path, the check valve being arranged in the valve chamber;
an on-off valve disposed in a flow path that communicates the first flow path with a primary system;
a pressure measuring means disposed in a secondary system connected to the second flow path;
a control device to which the measured value of the pressure measuring means is input and which opens and closes the on-off valve,
The control device is a fluid supply system in which, when the pressure value measured by the pressure measuring means falls below a threshold value, the control device opens the on-off valve to supply fluid from the primary system to the secondary system. 2. The fluid supply system according to claim 1, wherein the valve body is tubular and has a bottom, a seat portion at a tip portion which serves as a bottom and abuts against the valve seat portion , an outer peripheral surface at a rear end portion which is in sliding contact with the valve chamber, and an opening portion which communicates with the interior of the valve body is formed between the tip end and the rear end portion.

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