non-return valve

Abstract

The present invention provides a check valve that can open with a small pressure difference between the primary and secondary sides, while reliably closing if fluid flows in the reverse direction. [Solution] The valve seat 3 has a valve hole 30 through which fluid flows, a valve body 4 positioned on the secondary side of the valve hole 30 and opening and closing the valve hole 30 by being displaced in the axial direction δ of the valve hole 30, a valve stem 5 extending from the valve body 4 to the secondary side, and a valve closing assisting part 6 that assists the valve body 4 in closing the valve hole 30. The valve closing assisting part 6 is positioned on the secondary side of the valve stem 5 and has a rotating shaft portion 60 that intersects the axial direction δ, and a contact portion 62 that, by receiving the fluid flow from the secondary side and rotating around the rotating shaft portion 60, contacts the tip portion 52 of the valve stem 5 so as to push the valve body 4, which is in an open state, toward the primary side in the axial direction δ.

Description

Technical Field

[0001] The technology of the present disclosure relates to a check valve.

Background Art

[0002] Conventionally, as a check valve that allows fluid to flow in one direction (forward direction) while preventing fluid from flowing in the opposite direction (reverse direction), there is known one including an annular valve seat in which a valve hole through which fluid flows is formed, a valve body that opens and closes the valve hole by being displaced in the axial direction of the valve hole, and a biasing member (coil spring) that biases the valve body toward the primary side against the valve seat (see, for example, Patent Document 1). Such a check valve opens when the primary side pressure (the pressure on the primary side with respect to the valve body) becomes high to such an extent that the differential pressure between the primary side pressure and the secondary side pressure (the pressure on the secondary side with respect to the valve body) exceeds the biasing force of the coil spring, and the valve body opens the valve hole. On the other hand, when the primary side pressure becomes low to such an extent that the differential pressure becomes less than or equal to the biasing force of the coil spring, the valve body closes the valve hole to close the valve.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to open the above-described conventional check valve, it is necessary that the differential pressure between the primary side pressure and the secondary side pressure exceeds the biasing force of the coil spring. However, depending on the use environment, application, etc., there is a need for a check valve that can be opened with a smaller differential pressure. However, if the coil spring is simply removed in order to enable the check valve to be opened with a smaller differential pressure, there will be no member that applies a force to the primary side to the valve body. Therefore, when fluid flows in from the secondary side, that is, in the reverse direction, there is a risk that the valve body does not close the valve hole as desired, and thus the check valve does not close as desired.

[0005] This disclosure has been made in consideration of the above, and aims to provide a check valve that can open with a small pressure difference between the primary and secondary sides, while reliably closing when fluid flows in the reverse direction. [Means for solving the problem]

[0006] To achieve the above objective, the check valve according to the present disclosure comprises a valve seat having a valve hole through which fluid flows, a valve body disposed on the secondary side with respect to the valve hole and opening and closing the valve hole by being displaced in the axial direction of the valve hole, a valve stem extending from the valve body to the secondary side, and a valve closing assisting part that assists the valve body in closing the valve hole, wherein the valve closing assisting part is disposed on the secondary side with respect to the valve stem and has a rotating shaft portion that intersects the axial direction, and a contact portion that, by receiving the flow of fluid from the secondary side and rotating around the rotating shaft portion, contacts the tip of the valve stem so as to push the valve body, which is in an open state, toward the primary side in the axial direction.

[0007] According to the above configuration, the check valve opens and closes as the valve body is displaced axially from the valve hole. Specifically, when the primary pressure becomes higher than the secondary pressure, the valve body is subjected to the fluid flow (hydrodynamic force) from the primary side and displaces axially away from the valve seat, thereby opening the valve hole. In this way, the check valve opens when the primary pressure becomes higher than the secondary pressure. Furthermore, since the above check valve does not have a component that biases the valve body toward the primary side towards the valve seat, such as a coil spring in conventional technology, the check valve can be opened with only a small pressure difference between the primary and secondary pressures.

[0008] Conversely, if the secondary pressure becomes higher than the primary pressure, the valve body will receive fluid flow from the secondary side and attempt to close the valve hole by displacing axially towards the valve seat. However, some of the fluid flowing in from the secondary side may flow around the valve body instead of pushing it towards the primary side. As a result, there is a risk that the fluid force pushing the valve body towards the primary side will be insufficient, and the valve body will not close the valve hole as desired. Therefore, the check valve according to this disclosure is equipped with a valve closing assisting part that assists the valve body in closing the valve hole.

[0009] Because the valve closing assisting part has the aforementioned contact portion, when fluid flows in from the secondary side, the contact portion receives the flow of the fluid and rotates around the rotating shaft portion, causing it to contact the tip of the valve stem in such a way that it pushes the valve body, which is in an open state, toward the primary side in the axial direction. As a result, when fluid flows in from the secondary side, i.e., in the reverse direction, a force toward the primary side can be applied to the valve body in addition to the fluid force from the secondary side, and therefore the check valve can be reliably closed.

[0010] Thus, with the above configuration, the check valve can be opened by a small pressure difference between the primary and secondary sides, while reliably closing if fluid flows in the reverse direction.

[0011] In the above-described check valve, the valve closing auxiliary part has an impeller part that rotates around the rotating shaft part in response to the fluid flow from the secondary side, and the contact part may be attached to the impeller part. With this configuration, the area that receives the fluid flow is increased compared to the case where the contact part alone receives the fluid flow from the secondary side. As a result, the contact part can be rotated by utilizing the fluid flow from the secondary side more efficiently.

[0012] In the above-described check valve, the contact portion may be formed integrally with the impeller portion. This configuration reduces the number of parts compared to the case where the contact portion is formed separately from the impeller portion, and therefore reduces the assembly cost of the check valve.

[0013] In the above-described check valve, at least one of the tip of the valve stem and the contact portion may have a spherical surface. With this configuration, compared to the case where neither the tip of the valve stem nor the contact portion has a spherical surface, the frictional resistance between the contact portion and the valve stem when the valve body is displaced together with the valve stem pushed from the contact portion can be reduced, and therefore the valve body can be displaced more efficiently toward the primary side in the axial direction. [Effects of the Invention]

[0014] As described above, according to the present disclosure, while opening the check valve with a slight differential pressure between the primary pressure and the secondary pressure, the check valve can be reliably closed when the fluid flows backward.

Brief Description of the Drawings

[0015] [Figure 1] FIG. 1 is a longitudinal sectional view of a check valve in one embodiment. [Figure 2] FIG. 2 is a sectional view taken along line A-A of FIG. 1. [Figure 3] FIG. 3 is a sectional view taken along line B-B of FIG. 1. [Figure 4] FIG. 4 is a schematic view showing the inside of the check valve when the valve body is in the closed position. [Figure 5] FIG. 5 is a schematic view for explaining the behavior of the valve body when the check valve opens. [Figure 6] FIG. 6 is a schematic view (1) for explaining the behavior of the closing assist portion. [Figure 7] FIG. 7 is a schematic view (2) for explaining the behavior of the closing assist portion. [Figure 8] FIG. 8 is a schematic view (3) for explaining the behavior of the closing assist portion. [Figure 9] FIG. 9 is a schematic view (4) for explaining the behavior of the closing assist portion. [Figure 10] FIG. 10 is a schematic view showing a part of the check valve in the modification (1). [Figure 11] FIG. 11 is a schematic view showing a part of the check valve in the modification (2). [Figure 12] FIG. 12 is a schematic view showing a part of the check valve in the modification (3). [Figure 13] FIG. 13 is a schematic view showing a part of the check valve in the modification (4). [Figure 14] FIG. 14 is a diagram for explaining an example of the positional relationship between the contact portion and the tip of the valve rod.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. <Configuration of check valve> FIG. 1 is a longitudinal sectional view of a check valve 1 in an embodiment. FIG. 1 shows a state where the check valve 1 is open. FIG. 2 is a sectional view taken along line A-A of FIG. 1. FIG. 3 is a sectional view taken along line B-B of FIG. 1. The check valve 1 allows the flow of fluid in one direction (the forward direction from the inlet 1a to the outlet 1b), while blocking the flow in the opposite direction (the reverse direction). The thick arrow in FIG. 1 conceptually shows the forward flow of the fluid. The check valve 1 is used, for example, in a microgravity environment, and the fluid is air (gas) containing, for example, carbon dioxide. As shown in FIG. 1, the check valve 1 includes a casing 2, a valve seat 3, a valve body 4, and a valve rod 5. Hereinafter, each of these components will be described in order.

[0017] As shown in FIG. 1, the casing 2 is formed in a cylindrical shape with an inlet 1a formed at one end and an outlet 1b formed at the other end. A flow path is formed in the casing 2 that leads from the inlet 1a to the outlet 1b.

[0018] The casing 2 is formed by connecting a primary side member 21 and a secondary side member 22, both of which are formed in a cylindrical shape. An inlet 1a is formed at one end of the primary side member 21, and a male thread 23 is formed on the outer peripheral wall at the end opposite to the inlet 1a. Similarly, an outlet 1b is formed at one end of the secondary side member 22, and a female thread 24 is formed on the inner peripheral wall at the end opposite to the outlet 1b. The primary side member 21 and the secondary side member 22 are connected to each other by screwing these male thread 23 and female thread 24 together.

[0019] As shown in FIG. 2, inside the primary side member 21, a primary side guide portion 25 for guiding the valve rod 5 in the axial direction δ of a valve hole 30 to be described later is provided. The primary side guide portion 25 has an annular portion 251 in which a guide hole 250 through which the valve rod 5 is inserted is formed, and a connecting portion 252 that connects the annular portion 251 and the inner peripheral wall of the primary side member 21. The primary side guide portion 25 is formed integrally with the primary side member 21, for example.

[0020] Similarly, as shown in Figure 3, a secondary guide portion 26 is provided inside the secondary member 22 to guide the valve stem 5 in the axial direction δ. The secondary guide portion 26 has an annular portion 261 through which a guide hole 260 is formed, through which the valve stem 5 is inserted, and a connecting portion 262 that connects the annular portion 261 to the inner circumferential wall of the secondary member 22. As shown in Figure 1, the connecting portion 262 of the secondary guide portion 26 is formed such that the radially outer portion is raised one step towards the inlet 1a, and this raised portion functions as a limiting portion 9 that restricts the displacement of the valve body 4, which will be described later. The secondary guide portion 26 is formed integrally with the secondary member 22, for example.

[0021] As shown in Figure 1, the valve seat 3 is located in the central part of the internal space of the casing 2 in the direction of the cylindrical axis, specifically, it is formed on the end face of the primary side member 21 opposite to the inlet 1a. The valve seat 3 has a valve hole 30 through which fluid flows, and as shown in Figure 2, the valve seat 3 is formed in an annular shape. The axial direction δ of the valve hole 30 is aligned with the direction of fluid flow.

[0022] Figure 4 is a schematic diagram showing the inside of the check valve 1 when the valve body 4 is in the closed position. As shown in Figure 1, the valve body 4 is positioned on the secondary side of the valve hole 30 and is formed in the shape of a disc concentric with the valve hole 30. The valve body 4 is displaceable in the axial direction δ between the open position and the closed position, and the valve hole 30 is opened and closed by displacing it in the axial direction δ. The open position of the valve body 4 is the position where it is separated from the valve seat 3 and the valve hole 30 is open, as shown in Figure 1, and is limited to the position where further displacement in the axial direction δ toward the secondary side (direction δ2) is limited by interference with the limiting part 9 (fully open position). On the other hand, the closed position of the valve body 4 is the position where it is seated on the valve seat 3 and the valve hole 30 is closed, as shown in Figure 4.

[0023] The check valve 1 is not provided with a biasing member (such as a coil spring in the prior art) that biases the valve body 4 toward the primary side toward the valve seat 3. As a result, the valve body 4 can be easily displaced toward the secondary side in the axial direction δ (direction δ2).

[0024] As shown in Figure 1, the valve stem 5 has a primary valve stem 50 extending from the valve body 4 along the axial direction δ toward the primary side, and a secondary valve stem 51 extending from the valve body 4 along the axial direction δ toward the secondary side. In this embodiment, the tip portion 52 of the secondary valve stem 51 (corresponding to the tip portion described in the claim) is formed in a hemispherical shape having a spherical surface. The primary valve stem 50, the secondary valve stem 51, and the valve body 4 are integrally formed, for example, by machining (cutting).

[0025] Figure 5 is a schematic diagram illustrating the behavior of the valve body 4 when the check valve 1 opens. The check valve 1 described above opens and closes as the valve body 4 is displaced in the axial direction δ. Specifically, when the primary pressure (pressure on the primary side relative to the valve body 4) becomes higher than the secondary pressure (pressure on the secondary side relative to the valve body 4), the valve body 4 receives fluid flow (hydrodynamic force) from the primary side and displaces away from the valve seat 3 (in the direction δ2 toward the secondary side in the axial direction δ), as shown by arrow F1 in Figure 5, thereby opening the valve hole 30. In this way, the check valve 1 opens when the primary pressure becomes higher than the secondary pressure. Furthermore, since the above check valve 1 does not have a component that biases the valve body 4 toward the primary side towards the valve seat 3, such as a coil spring in the conventional technology, the check valve 1 can be opened with a small pressure difference between the primary and secondary pressures. Therefore, the check valve 1 is particularly suitable for microgravity environments, weightless environments, and the like, where the gravity of the fluid has little effect on the fluid pressure, and thus a pressure difference between the primary and secondary sides is unlikely to occur.

[0026] Conversely, if the secondary pressure becomes higher than the primary pressure, the valve body 4 receives the fluid flow from the secondary side and displaces itself (in the axial direction δ1 toward the primary side) to approach the valve seat 3, attempting to close the valve hole 30. However, some of the fluid flowing in from the secondary side may flow around the valve body 4 instead of pushing it toward the primary side. As a result, there is a risk that the fluid force pushing the valve body 4 toward the primary side will be insufficient, and the valve body 4 will not close the valve hole 30 as desired. Therefore, the check valve 1 according to this disclosure is equipped with a valve closing assisting part 6 that assists the valve body 4 in closing the valve hole 30. The valve closing assisting part 6 will be described in detail below.

[0027] <Configuration of the valve closing assist unit> As shown in Figure 1, the valve closing assist unit 6 has a rotating shaft portion 60 positioned on the secondary side with respect to the valve stem 5, an impeller portion 61 that rotates around the rotating shaft portion 60 in response to the fluid flow from the secondary side, and a contact portion 62 attached to the impeller portion 61.

[0028] The rotating shaft portion 60 intersects the axial direction δ, and in this embodiment, it is perpendicular to the axial direction δ. The rotating shaft portion 60 is positioned to cross the flow path within the casing 2, and both ends of the rotating shaft portion 60 are connected to the inner circumferential wall of the secondary side member 22 in the casing 2. The rotating shaft portion 60 is formed integrally with, for example, the secondary side member 22.

[0029] The impeller section 61 includes a shaft cylinder 610 whose inner circumferential surface faces the outer circumferential surface of the rotating shaft section 60 and which is attached (loosely fitted) to the rotating shaft section 60 with some play, and a single blade 611 attached to the outer circumferential surface of the shaft cylinder 610. The blade 611 is formed in the shape of a rectangular plate that extends radially to the rotating shaft section 60 and has a main surface 613 facing the circumferential direction of the rotating shaft section 60. The impeller section 61 is rotatable about the rotating shaft section 60 because the shaft cylinder 610 is loosely fitted to the rotating shaft section 60, and it rotates about the rotating shaft section 60 by receiving fluid flow from the secondary side on the main surface 613 of the blade 611. The impeller section 61 is prevented from being displaced in the direction along the rotating shaft section 60 by, for example, a stopper (not shown) attached to the rotating shaft section 60.

[0030] The contact portion 62 is attached to the axial center of the rotating shaft portion 60 of the blade 611 in the impeller portion 61, so as to protrude from the edge of the tip portion 612 of the blade 611. In this embodiment, the contact portion 62 is formed in a spherical shape having a spherical surface. Also in this embodiment, the contact portion 62 is formed integrally with the impeller portion 61.

[0031] As described above, the contact portion 62 is supported so as to be rotatable about the rotating shaft portion 60 by an impeller portion 61 that is rotatable about the rotating shaft portion 60. As a result, the contact portion 62 rotates about the rotating shaft portion 60 in response to the fluid flow from the secondary side. As described above, because the rotating shaft portion 60 intersects with the axial direction δ, the contact portion 62 can face the axial direction δ when it rotates about the rotating shaft portion 60. Then, by rotating about the rotating shaft portion 60 in response to the fluid flow from the secondary side, the contact portion 62 comes into contact with the tip portion 52 of the valve stem 5, pushing the valve body 4, which is in the open state of the valve hole 30, toward the primary side in the axial direction δ. The specific contact position of the contact portion 62 with respect to the tip portion 52 of the valve stem 5 will be explained in conjunction with the behavior of the valve closing assist portion 6 below.

[0032] <Behavior of the valve closing assist mechanism> Figures 6 to 9 are schematic diagrams (1) to (4) illustrating the behavior of the valve closing assist unit 6. Figures 6 and 7 show the axial direction of the rotating shaft 60 aligned perpendicular to the plane of the paper. Next, the behavior of the valve closing assist unit 6 described above will be explained. First, as shown in Figure 6, when the check valve 1 is open (the valve body 4 is opening the valve hole 30) and no fluid is flowing in from the secondary side, the contact portion 62 of the valve closing assist unit 6 is in a free state and is not subjected to external force, and can be at any position on the rotation trajectory P centered on the rotating shaft 60.

[0033] When the secondary pressure becomes higher than the primary pressure from the state shown in Figure 6, fluid flows in from the secondary side, as indicated by arrow F2 in Figures 7 and 8. As indicated by arrow F3 in Figures 7 and 8, the contact portion 62 rotates around the rotating shaft portion 60 in response to the fluid flow from the secondary side, and as indicated by arrow F4 in Figure 7, it contacts the tip 52 of the valve stem 5, pushing the valve body 4, which is in an open state with the valve hole 30 open, toward the primary side in the axial direction δ. At this time, as shown in Figure 7, the direction in which the contact portion 62 pushes the tip 52 of the valve stem 5 is along the velocity direction of the contact portion 62 (tangential direction on the rotation trajectory P) and includes a component T1 that points toward the primary side in the axial direction δ. Specifically, when the contact portion 62 contacts the tip 52 of the valve stem 5, it is in a position just before the velocity direction becomes perpendicular to the axial direction δ. The position just before the velocity direction becomes perpendicular to the axial direction δ is defined as the position where, as shown in Figure 7, the rotation angle α is the angle that increases with the rotation of the contact portion 62, and the rotation angle α when the tangential direction of the contact portion 62 is perpendicular to the axial direction δ is 90°, and the rotation angle α is between 0° and 90°. To achieve such contact, the positional relationship between the tip 52 of the valve stem 5 and the contact portion 62 is set so that they overlap on the axial direction δ when the valve body 4 is opening the valve hole 30.

[0034] As described above, with the valve body 4 opening the valve hole 30, the contact portion 62 of the valve closing assisting part 6 contacts the tip portion 52 of the valve stem 5 by receiving the fluid flow from the secondary side. This applies a force to the valve body 4 via the valve stem 5, which includes a component T1 directed toward the primary side in the axial direction δ. As a result, the valve body 4 is displaced toward the primary side in the axial direction δ (direction δ1), as shown by arrow F5 in Figure 9. In this way, the valve closing assisting part 6 helps the valve body 4 close the valve hole 30 by applying a force toward the primary side to the valve body 4 using the fluid flow from the secondary side while the valve body 4 is opening the valve hole 30.

[0035] Conversely, even if the primary pressure becomes higher than the secondary pressure, the contact portion 62 of the valve closing auxiliary portion 6 rotates in response to the fluid flow from the primary side, but this does not hinder the displacement of the valve body 4 toward the secondary side in the axial direction δ (direction δ2).

[0036] Because the valve closing assisting part 6 has the contact part 62 described above, when fluid flows in from the secondary side, the contact part 62 receives the flow of the fluid and rotates around the rotating shaft part 60, causing it to contact the tip 52 of the valve stem 5 so as to push the valve body 4, which is in the open state of the valve hole 30, toward the primary side in the axial direction δ. As a result, when fluid flows in from the secondary side, i.e., in the reverse direction, a force toward the primary side can be applied to the valve body 4 separately from the fluid force from the secondary side, and therefore the check valve 1 can be reliably closed.

[0037] Thus, with the above configuration, the check valve 1 can be opened by a small pressure difference between the primary and secondary sides, while at the same time, the check valve 1 can be reliably closed if fluid flows in the reverse direction.

[0038] Furthermore, as described above, because the contact portion 62 is attached to the impeller portion 61, the area that receives the fluid flow from the secondary side is increased compared to the case where the contact portion 62 alone receives the fluid flow from the secondary side. As a result, the contact portion 62 can be rotated by utilizing the fluid flow from the secondary side more efficiently.

[0039] Furthermore, as described above, since the contact portion 62 is integrally formed with the impeller portion 61, the number of parts can be reduced compared to the case where the contact portion 62 is formed separately from the impeller portion 61, and therefore the assembly cost of the check valve 1 can be reduced.

[0040] In the above embodiment, both the tip portion 52 and the contact portion 62 of the valve stem 5 had spherical surfaces. However, the embodiment is not limited to this, and at least one of the tip portion 52 and the contact portion 62 of the valve stem 5 may have a spherical surface. This reduces the frictional resistance between the contact portion 62 and the valve stem 5 when the valve body 4 is displaced together with the valve stem 5 pushed by the contact portion 62, compared to the case where neither the tip portion 52 nor the contact portion 62 of the valve stem 5 has a spherical surface. Therefore, the valve body 4 can be displaced more efficiently toward the primary side in the axial direction δ.

[0041] <Variation> The check valve 1 described above is applicable to various gases and liquids. Furthermore, the check valve 1 is not limited to the above embodiment and may be configured as follows.

[0042] Figures 10 to 13 are schematic diagrams showing parts of the check valve 1 in modified examples (1) to (4). As shown in Figure 10, the contact portion 62 of the valve closing auxiliary portion 6 is integrally formed with the blades 611 of the impeller portion 61, and may also be formed in the shape of a plate having the same thickness as the blades 611. This allows the contact portion 62 and the blades 611 to be formed simultaneously by punching.

[0043] Furthermore, as shown in Figure 11, the valve closing assisting part 6 may have a support part 63 that includes a pair of L-shaped support arms 631 that extend radially from the outer circumferential surface of a shaft cylinder 630 similar to the shaft cylinder 610 above and then bend to face each other, instead of the impeller part 61 described above. The contact portion 62 of the valve closing assisting part 6 may be attached so as to be sandwiched between the pair of support arms 631 of the support part 63, instead of being attached to the blades 611 of the impeller part 61, and thus be rotatably supported by the support part 63 around the rotating shaft part 60. This allows the contact portion 62 to be rotatably supported by the support part 63, which has a smaller volume in shape than the impeller part 61, and therefore the valve closing assisting part 6 can be easily made lighter as needed, and the contact portion 62 can be rotated with less fluid force. In this case, the contact portion 62 may be integrally formed with the support arms 631. This reduces the number of parts compared to the case where the contact portion 62 is formed separately from the support arm 631, and therefore reduces the assembly cost of the check valve 1.

[0044] Furthermore, the contact portion 62 may be formed in a cylindrical shape extending in the axial direction of the rotating shaft portion 60, as shown in Figure 12, or it may be formed in a barrel shape with the axial central part of the rotating shaft portion 60 bulging radially outward, as shown in Figure 13. This makes it possible to reuse other cylindrical or barrel-shaped parts as the contact portion 62, for example, thereby improving the design flexibility of the check valve 1.

[0045] Figure 14 is a diagram illustrating an example of the positional relationship between the contact portion 62 and the tip portion 52 of the valve stem 5. As shown in Figure 14, when the tip portion 52 of the valve stem 5 is formed in a hemispherical shape, it is preferable that the positional relationship between the tip portion 52 of the valve stem 5 and the contact portion 62 is set such that the angle β between the imaginary line connecting the contact point C with the contact portion 62 and the center of the hemisphere at the tip portion 52 and the axis of the valve stem 5 is greater than 0° and less than or equal to 45°. As a result, the contact portion 62 contacts the portion of the valve stem 5 that is close to the axis, allowing force to be applied to the valve stem 5 more efficiently.

[0046] Furthermore, the rotating shaft portion 60 of the valve closing auxiliary portion 6 may be formed separately from the secondary side member 22. This allows for the reuse of other axial components as the rotating shaft portion 60, thereby increasing the design flexibility of the check valve 1. In this case, both ends of the rotating shaft portion 60 and the secondary side member 22 may be connected, for example, via a sealing member, to prevent fluid leakage.

[0047] Furthermore, a bearing may be provided between the inner circumferential surface of the shaft cylinder 610 of the impeller section 61 and the outer circumferential surface of the rotating shaft section 60 in order to reduce frictional resistance between them.

[0048] Furthermore, the contact portion 62 may be formed separately from the impeller portion 61. This allows for the reuse of other parts as the contact portion 62, thereby increasing the design flexibility of the check valve 1. In this case, it may be attached to the impeller portion 61, etc., by welding, for example. Alternatively, the contact portion 62 may be attached to a part of the impeller portion 611 other than the tip portion 612, as long as the positional relationship with the tip portion 52 of the valve stem 5 is satisfied.

[0049] The blades 611 may be provided in multiple units. This allows the fluid flow from the secondary side to be received sequentially by multiple blades 611, and therefore the contact portion 62 can be rotated by utilizing the fluid flow from the secondary side more efficiently.

[0050] The embodiments described above are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of this disclosure is not construed solely by the embodiments and examples described above, but is defined by the claims. Furthermore, any modifications or changes within the equivalent scope of the claims are all within the scope of this disclosure. [Explanation of Symbols]

[0051] 1. Check valve 3 valve seats 30 valve holes 4 Valve body 5 valve stems 52 Tip 6. Valve closing assist unit 60 Rotating shaft section 61 Impeller section 62 Contact part δ axis direction

Claims

1. A valve seat in which a valve opening through which fluid flows is formed, A valve body positioned on the secondary side of the valve hole, which opens and closes the valve hole by being displaced in the axial direction of the valve hole, A valve stem extending from the valve body to the secondary side, The valve body is further equipped with a valve closing assisting part that assists in closing the valve hole, The aforementioned valve closing assisting unit is A rotating shaft portion is positioned on the secondary side with respect to the valve stem and intersects with the axial direction, A check valve having a contact portion that contacts the tip of the valve stem so as to push the valve body, which is in an open state with its valve hole open, toward the primary side in the axial direction when it rotates around the rotating shaft portion in response to the fluid flow from the secondary side.

2. In the check valve according to claim 1, The aforementioned valve closing assisting unit is It has an impeller section that rotates around the aforementioned rotating shaft section in response to the fluid flow from the secondary side, The aforementioned contact portion is a check valve attached to the impeller portion.

3. In the check valve according to claim 2, The contact portion is a check valve formed integrally with the impeller portion.

4. In the check valve according to claim 1, A check valve wherein at least one of the tip of the valve stem and the contact portion has a spherical surface.

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