JP6425451B2 - Check valve - Google Patents

Description

  The present invention relates to a check valve that allows fluid flow in only one direction.

  Conventionally, as disclosed in, for example, Patent Document 1, a non-return valve provided with a spring for biasing a valve body to an inlet is well known. The check valve is provided in a casing having a fluid inlet (inlet) and an outlet (outlet), a valve body for opening and closing the inlet, and a valve body provided downstream of the valve body for receiving the valve body. And a coil spring for biasing. In such a check valve, when the fluid pressure on the inlet side is greater than the sum of the fluid pressure on the outlet side and the biasing force of the coil spring, the valve body is displaced downstream and the inlet is opened. This allows fluid flow from the inlet to the outlet. When the fluid pressure on the inlet side is smaller than the sum of the fluid pressure on the outlet side and the biasing force of the coil spring, the valve body is displaced upstream to close the inlet. This prevents the flow of fluid from the outlet to the inlet.

Japanese Patent Application Laid-Open No. 10-30743

  In the above-described conventional check valve, there is a case where a chattering phenomenon occurs in which the valve body frequently repeats opening and closing operation and vibrates at low flow rate (when the flow rate of fluid is small). That is, at low flow rates, the fluid pressure becomes unstable and pressure fluctuations (pressure pulsations) of the fluid occur frequently, so that the valve body repeats opening and closing operations in a short cycle. The chattering phenomenon not only causes noise but also causes wear of the valve body, the valve seat, etc., resulting in a decrease in life.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a check valve capable of suppressing a chattering phenomenon at a low flow rate.

  The check valve according to the present invention includes a casing, a valve portion, a cover member, and a spring. The casing has a valve chamber, and fluid inlets and outlets formed on the upstream and downstream sides of the valve chamber. The valve portion is accommodated in the valve chamber, and opens and closes the inflow port by being displaced in the upstream and downstream directions. The covering member is accommodated displaceably in the upstream and downstream directions in the valve chamber and covers the inlet and the valve portion from the downstream side to define a displacement space of the valve portion, and the displacement space and the outside A communication hole is formed to communicate the The spring biases the cover member upstream.

  As described above, according to the present invention, the valve portion for opening and closing the inflow port is provided in a substantially free state, and the valve portion and the periphery of the inflow port are covered to define the displacement space of the valve portion. And a cover member having a communication hole formed therein for communicating the two members, and the cover member is urged upstream by a spring. Therefore, at the time of normal flow rate, as shown in FIG. 3, the valve portion is displaced to the downstream side to open the inflow port, and the cover member is displaced to the downstream side against the biasing force of the spring. Thus, a normal flow of fluid can be allowed to pass. On the other hand, when the flow rate is low, as shown in FIG. 2, the valve portion is displaced downstream to open the inlet, while the cover member is not displaced. In this state, the fluid that has flowed into the displacement space from the inlet flows to the outside (valve chamber) through the communication hole and flows out from the outlet. Here, even if the pressure fluctuation of the fluid occurs, since the biasing force of the spring does not act on the valve portion, the valve portion is always pushed to the downstream side. Therefore, the valve portion does not move while being displaced downstream. Therefore, at the time of low flow rate, it is possible to suppress the chattering phenomenon in which the valve unit repeats the opening and closing operation in a short cycle.

FIG. 1 is a cross-sectional view showing a schematic configuration of a check valve according to the embodiment. FIG. 2 is a cross-sectional view showing a low flow rate state of the check valve according to the embodiment. Drawing 3 is a sectional view showing the state at the time of the usual flow of the nonreturn valve concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are essentially preferred examples, and are not intended to limit the scope of the present invention, its applications, or its applications.

  The check valve 1 of the present embodiment is provided in a pipe through which a fluid such as liquid or gas flows. As shown in FIG. 1, the check valve 1 includes a casing 10, a valve body 20, a cover member 30, a coil spring 40, and a spring receiving member 45.

  The casing 10 is formed in a substantially cylindrical shape by screwing the upstream side member 11 and the downstream side member 12. The axial direction of the casing 10 coincides with the fluid flow direction (up and down direction). In the casing 10, an inlet 13 and an outlet 14 are formed at both axial ends. The inlet 13 and the outlet 14 are formed in a circular shape. The casing 10 has a valve chamber 15 formed between the inlet 13 and the outlet 14. That is, in the casing 10, the inlet 13 is formed on the upstream side of the valve chamber 15, and the outlet 14 is formed on the downstream side of the valve chamber 15. An annular valve seat 16 is formed at the inner edge of the inflow port 13.

  In the valve chamber 15, the valve body 20, the cover member 30, the coil spring 40 and the spring receiving member 45 are accommodated. The casing 10, the valve body 20, the cover member 30, the coil spring 40 and the spring receiving member 45 are provided coaxially with each other.

  The valve body 20 has a valve portion 21 and a shaft portion 22. The valve portion 21 is formed in a disk shape (disk shape), and opens and closes the inlet 13. The shaft portion 22 is an axis extending in the upstream and downstream directions with a circular cross section, and is connected to the downstream side of the valve portion 21. The shaft portion 22 is provided coaxially with the valve portion 21 (at the center of the valve portion 21) and integrally formed with the valve portion 21. The valve body 21 opens and closes the inlet 13 by displacing (moving) the valve body 20 in the upstream and downstream directions. That is, when the valve portion 21 is displaced to the upstream side and is seated on the valve seat 16, the inflow port 13 is closed, and when the valve portion 21 is displaced to the downstream side and separated from the valve seat 16, the inflow port 13 is opened.

  The covering member 30 is formed in a circular slightly flat box shape whose one end is open. The covering member 30 is configured to be displaceable in the upstream and downstream directions with the closed end 31 located on the downstream side and the open end 33 located on the upstream side. Further, the covering member 30 is arranged to cover the inflow port 13 and the valve portion 21 from the downstream side so as to define the displacement space 36 of the valve portion 21. That is, in the displacement space 36, the open end 33 of the cover member 30 is in contact with the end surface 17 of the upstream member 11 (the surface on the inlet 13 side forming the valve chamber 15). It is a closed space formed. Thus, the valve portion 21 of the valve body 20 is accommodated in the displacement space 36. Further, on the downstream side member 12 of the casing 10, a plurality of ribs 12a for guiding the covering member 30 in the upstream and downstream directions are formed. The rib 12 a is formed on the inner peripheral surface of the downstream side member 12 forming the valve chamber 15. The rib 12 a protrudes from the inner peripheral surface of the downstream side member 12 and extends in the up-down direction along the side wall 32 of the covering member 30. That is, the covering member 30 is displaced in the up-down direction along the rib 12 a of the downstream side member 12.

  A guide hole 34 is formed at the center of the closed end 31 of the cover member 30. In the guide hole 34, the shaft portion 22 of the valve body 20 is inserted so as to be displaceable in the upstream and downstream directions, and the valve body 20 supports the shaft portion 22 so as to be displaceable in the upstream and downstream direction. That is, the valve body 20 is supported by the cover member 30 so as to be displaceable in the upstream and downstream directions. Further, at the closed end 31 of the cover member 30, a plurality of communication holes 35 are formed in the outer edge portion. The communication hole 35 communicates the displacement space 36 with the outside thereof (the valve chamber 15).

  One end (upstream end) of the coil spring 40 is in contact with the closed end 31 of the covering member 30, and the other end (downstream end) is in contact with the spring receiving member 45. The coil spring 40 biases the cover member 30 to the upstream side, and constitutes a spring according to the present invention. The spring receiving member 45 receives and supports the coil spring 40. The spring receiving member 45 is formed with one through hole 46 at the center and a plurality of through holes 47 on the outer peripheral side. The flow holes 46 and 47 are holes through which fluid flows.

<Opening and closing operation>
In the check valve 1 of the present embodiment, the open / close operation differs between the normal flow rate where the flow rate is relatively large and the low flow rate when the flow rate is small. At the time of normal flow rate, as shown in FIG. 2, first, the valve body 20 is displaced (moved) to the downstream side by fluid pressure on the upstream side (inflow port 13 side) to be separated. Thereby, the inflow port 13 is opened. When the inlet 13 opens, fluid flows from the inlet 13 into the displacement space 36 of the closed space. In the displacement space 36, the pressure rises even though the fluid flows out to the valve chamber 15 through the communication hole 35. Then, when the pressure (fluid pressure) of the displacement space 36 becomes higher than the fluid pressure (including the biasing force of the coil spring 40) on the downstream side (the outlet 14 side), as shown in FIG. Displaces (moves) downstream against the biasing force. That is, the covering member 30 is separated from the end face 17 of the upstream side member 11. At this time, the valve body 20 is also displaced to the downstream side with the cover member 30. Thereby, the fluid flows directly into the valve chamber 13 from the inlet 13 and flows out from the outlet 14. Thus, at normal flow rates, a relatively large flow rate of fluid can flow.

  Next, at a low flow rate, as shown in FIG. 2, the valve body 20 is displaced (moved) to the downstream side by fluid pressure on the upstream side (inflow port 13 side) to be separated. Thereby, the inflow port 13 is opened. When the inlet 13 opens, fluid flows from the inlet 13 into the displacement space 36 of the closed space. In the displacement space 36, the fluid flows out to the valve chamber 15 through the communication hole 35. Further, in the displacement space 36, the pressure does not become higher than the downstream fluid pressure including the biasing force of the coil spring 40 because the flow rate of the fluid flowing in from the inlet 13 is small. Therefore, the covering member 30 remains in contact with the end face 17 of the upstream side member 11 without being displaced. Therefore, at this low flow rate, the fluid flowing into the displacement space 36 from the inlet 13 flows out to the valve chamber 13 through the communication hole 35 and then flows out from the outlet 14. Thus, when the flow rate is low, fluid can flow reliably even if the cover member 30 is not displaced.

  Here, when pressure fluctuation (pressure pulsation) occurs at the above-described low flow rate, the biasing force of the coil spring 40 does not act on the valve body 20, so the valve body 20 is always pushed downstream It becomes. That is, at low flow rates, only the upstream fluid pressure and the downstream fluid pressure act on the valve body 20, and even if pressure fluctuations occur, the downstream fluid pressure is higher than the upstream fluid pressure. Since the valve body 20 does not become high, the valve body 20 is always pushed downstream. Therefore, since the valve body 20 does not move while being displaced downstream, the chattering phenomenon in which the valve body 20 repeats the opening and closing operation in a short cycle is suppressed.

  As described above, in the check valve 1 of the above embodiment, the valve body 20 having the valve portion 21 for opening and closing the inflow port 13 is provided in a substantially free state, and the valve portion 21 and the periphery of the inflow port 13 are covered The displacement space 36 of 21 is defined, and the cover member 30 urged to the upstream side by the coil spring 40 is provided. Therefore, even if the pressure fluctuation of the fluid occurs at a low flow rate, the biasing force of the coil spring 40 does not act on the valve body 20 (valve portion 21), so the valve body 20 (valve portion 21) is displaced downstream. Can be maintained in Therefore, at the time of low flow rate, it is possible to suppress the chattering phenomenon in which the valve body 20 (valve portion 21) repeatedly repeats the opening and closing operation. Therefore, the non-return valve 1 which can reduce noise and wear of the valve body 20 etc. can be provided.

  Further, in the check valve 1 of the above embodiment, the shaft 22 extending in the upstream and downstream directions is connected to the downstream side of the valve 21, and the shaft 22 is inserted in the cover 30 so as to be displaceable in the upstream and downstream directions. Guide holes 34 are formed. Therefore, the valve body 20 (valve portion 21) can be supported so as to be displaceable in the upstream and downstream directions.

  The check valve 1 of the above embodiment may be configured as follows.

  For example, as a structure for supporting the valve body 20 (the valve portion 21) so as to be displaceable in the upstream and downstream directions, a plurality of protrusions that contact (slide contact) the inner surface of the side wall 32 of the cover member 30 are provided on the outer periphery of the valve portion 21 Alternatively, a plurality of ribs may be provided on the inner surface of the side wall 32 of the cover member 30 in contact (sliding contact) with the outer periphery of the valve portion 21. That is, the projection and the rib described above have a function of supporting the valve body 20 (the valve portion 21) and guiding the valve body 20 in the upstream and downstream directions. In this case, the shaft portion 22 of the valve body 20 and the guide hole 34 of the cover member 30 are omitted.

  Further, in the check valve 1 of the above embodiment, the cover member 30 is guided (displaced) in the upstream and downstream directions by the rib 12a provided on the downstream side member 12, but in the present invention, the cover is replaced instead A protrusion or a rib may be provided on the outer surface of the side wall 32 of the member 30 in contact (sliding contact) with the inner peripheral surface of the downstream member 12 (the inner peripheral surface of the downstream member 12 forming the valve chamber 15).

  Further, the check valve 1 of the above embodiment extends the shaft portion 22 of the valve body 20 to the downstream side and inserts it into the central flow hole 46 of the spring receiving member 45 and guides the extended shaft portion to the cover 30 It may be supported by the hole 34 and the flow hole 46 of the spring receiving member 45. In this case, not only the valve body 20 (the valve portion 21) but also the covering member 30 can be displaced (guided) in the upstream and downstream directions by the shaft portion, so the rib 12a provided on the downstream side member 12 is omitted.

  Further, in the above embodiment, the communication hole 35 of the cover member 30 may be formed not on the closed end 31 but on the side wall 32 or may be formed by cutting the open end 33.

  Moreover, in the said embodiment, the valve part 21 of the valve body 20 may be shapes other than disk shape, and you may make it form the cover member 30 in box shape other than circular.

  The present invention is useful for check valves that allow fluid flow in only one direction.

Reference Signs List 1 check valve 10 casing 13 inlet 14 outlet 15 valve chamber 21 valve 22 shaft 30 cover member 34 guide hole 35 communication hole 36 displacement space 40 coil spring (spring)

Claims (2)

A casing having a valve chamber, and fluid inlets and outlets formed upstream and downstream of the valve chamber;
A valve unit which is accommodated in the valve chamber and which opens and closes the inlet by being displaced in the upstream and downstream directions;
A communication hole which is accommodated displaceably in the upper and lower directions in the valve chamber and covers the inlet and the valve portion from the downstream side to define a displacement space of the valve portion while communicating the displacement space with the outside. A cover member on which the
A spring for urging the cover member upstream ;
The communication hole is formed at a position not blocked by the valve portion when the valve portion is displaced . In the check valve according to claim 1,
An axial portion extending in the upstream and downstream directions is connected to the downstream side of the valve portion,
The cover member is a check valve formed with a guide hole into which the shaft portion is inserted so as to be displaceable in the upstream and downstream directions.

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