Check valve

Abstract

To provide a check valve that opens with a small force but suppresses generation of a backflow.SOLUTION: A check valve 100 includes: a valve chamber 25 through which a fluid circulates from a primary side to a secondary side; a valve hole 21 provided in the valve chamber 25; a valve element 3 disposed on the secondary side of the valve hole 21 and displaced in an axial direction of the valve hole 21 to open and close the valve hole 21; and a nozzle 5 including a primary side opening 51 that opens in the axial direction of the valve hole 21 and toward the valve element 3 and a secondary side opening 52 having a diameter that is larger than that of the primary side opening 51 and disposed closer to the secondary side than the valve element 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology of the present disclosure relates to check valves. [Background technology]

[0002] A check valve is a mechanism that is provided in a pipe through which a fluid passes, and allows a flow in one direction but stops a flow in the opposite direction. Patent Document 1 discloses a spring-biased disc-shaped check valve having a casing with an inlet and an outlet, an annular valve seat provided between the inlet and the outlet, a disc-shaped valve body provided on the outlet side of the annular valve seat, and a spring that biases the disc-shaped valve body against the annular valve seat. In this configuration, when the pressure on the inlet side (primary side) becomes higher than the pressure on the outlet side (secondary side) and the pressure difference becomes greater than the biasing force of the spring, the valve opens to allow the fluid to flow from the inlet to the outlet. Also, when the pressure difference becomes lower than the biasing force, the valve closes, so that the fluid does not flow back from the outlet to the inlet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-030743 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional check valves, the difference between the pressure on the primary side and the pressure on the secondary side must exceed at least the biasing force of the spring in order for the valve to open. However, depending on the application, there is a demand for the valve to open with a very small pressure difference. On the other hand, if the spring is removed to meet this requirement, the valve disc will not close even if the secondary pressure becomes higher than the primary pressure, which may result in backflow. This is because when the valve hole is wide open, the fluid can bypass the valve disc and pass through the valve hole, making it difficult for the fluid to apply pressure in the valve closing direction.

[0005] The technology disclosed herein has been made in consideration of the above circumstances, and its purpose is to provide a check valve that opens the valve body with a smaller pressure difference than conventional spring-loaded check valves and can suppress the occurrence of backflow. [Means for solving the problem]

[0006] In order to solve the above problems, the check valve of the present invention comprises a valve chamber through which a fluid flows from a primary side to a secondary side, a valve hole provided in the valve chamber, a valve body arranged on the secondary side of the valve hole and opening and closing the valve hole by displacing in the axial direction of the valve hole, and a nozzle arranged on the secondary side of the valve body, the nozzle having a primary side opening that opens in the axial direction of the valve hole and toward the valve body, and a secondary side opening having a larger diameter than the primary side opening. Effect of the Invention

[0007] The check valve can open with a smaller pressure difference than before for a flow from the primary side to the secondary side. On the other hand, when a flow occurs in the reverse direction from the secondary side to the primary side, part of the flow passes through the nozzle. The flow velocity (fluid force) of the fluid passing through the nozzle increases, and this fluid collides with the valve disc, promoting the displacement of the valve disc in the valve closing direction. As a result, the valve is closed and the occurrence of a backflow can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view of a check valve when the valve element is in a fully open position. [Diagram 2] FIG. 2 is a plan view showing a casing and a primary-side holding member in the check valve of FIG. 1 as viewed from the valve hole side. [Diagram 3] 3 is a cross-sectional view of the casing of the check valve of FIG. 1 taken along the line C1-C1. [Figure 4] FIG. 4 is a perspective view of a nozzle in the check valve of FIG. [Diagram 5] 5(a) and 5(b) are cross-sectional views showing other examples of the nozzle. [Figure 6]FIG. 6 is a cross-sectional view showing a state in which the valve body is closed in the check valve of FIG. [Figure 7] FIG. 7 is a cross-sectional view showing another example of the shape of the end portion of the secondary shaft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. First embodiment Exemplary embodiments will now be described in detail with reference to the accompanying drawings.

[0010] (Check valve structure) Fig. 1 is a cross-sectional view of a check valve 100 in this embodiment. Fig. 2 is a plan view showing a casing 1 including a primary side holding member (holding member) 41 in the check valve 100, as viewed from the valve hole 21 side. Fig. 3 is a cross-sectional view of the casing 1 including a secondary side holding member (holding member) 42, taken along the C1-C1 arrows.

[0011] The check valve 100 is connected to a pipe through which a fluid flows, and allows the fluid to flow in the forward direction shown by the arrow in Fig. 1 from the primary side to the secondary side, while suppressing the occurrence of backflow. The check valve 100 includes a casing 1, and a valve body 3, a primary side shaft 31, a secondary side shaft 32, a primary side holding member 41, a secondary side holding member 42, a nozzle 5, and a protrusion 6, all of which are arranged within the casing 1. Each of the components will be described below.

[0012] The casing 1 has therein a valve hole 21, an outflow hole 22, an annular valve seat 23, and a valve chamber 25. The valve hole 21 has an axis A1, and fluid flowing in the antegrade direction passes through the valve hole 21 and flows into the valve chamber 25. The valve seat 23 is provided in the valve chamber 25 so as to surround the valve hole 21. Fluid flowing in the antegrade direction flows out of the valve chamber 25 through the outflow hole 22. In this way, the valve hole 21, the valve chamber 25, and the outflow hole 22 are aligned in this order on the axis A1, and form a flow path that penetrates the casing 1.

[0013] In this embodiment, the casing 1 has two cylindrical casing members that are connected by a threaded engagement in the axial direction A1. The two casing members are fixed to each other by a male thread structure formed on the outer surface of the primary casing member and a female thread structure formed on the inner surface of the secondary casing member.

[0014] The valve body 3 is a disk-shaped member that is coaxial with the axis A1.

[0015] The primary side shaft 31 and the secondary side shaft 32 are cylindrical members extending in the axial direction A1 from the centers of the primary side and secondary side surfaces of the valve body 3, respectively. In this embodiment, the primary side shaft 31 and the secondary side shaft 32 are molded integrally with the valve body 3.

[0016] The valve disc 3 opens and closes the valve hole 21 by being displaced in the axial A1 direction within the valve chamber 25. Specifically, the valve disc 3 can be displaced between a closed position where the valve hole 21 is closed and a fully open position where the valve hole 21 is fully opened. The closed position is a position where the valve disc 3 is seated on the valve seat 23, and the fully open position is a position where the valve disc 3 abuts against a protrusion 6 described below.

[0017] The primary side holding member 41 and the secondary side holding member 42 respectively hold the primary side shaft 31 and the secondary side shaft 32 so as to be movable in the axial direction A1.

[0018] 1 and 2, the primary side holding member 41 is provided on the primary side of the valve body 3, and has a through hole 44 coaxial with the axis A1. The primary side shaft 31 is inserted into the through hole 44, so that the primary side holding member 41 movably holds the primary side shaft 31. The periphery of the primary side holding member 41 is open to allow fluid to pass through. Particularly in this embodiment, the primary side holding member 41 is an elongated plate-like member that crosses the valve hole 21 in the radial direction.

[0019] 1 and 3, the secondary-side holding member 42 is provided on the secondary side of the valve body 3, and has a through hole 45 coaxial with the axis A1. The secondary-side shaft 32 is inserted into the through hole 45, so that the secondary-side holding member 42 movably holds the secondary-side shaft 32. The periphery of the secondary-side holding member 42 is open to allow fluid to pass through. Particularly in this embodiment, the secondary-side holding member 42 has a cross shape that radially crosses the outflow hole 22 in two directions.

[0020] With the above-described configuration, the valve element 3 is held by the primary side holding member 41, the primary side shaft 31, the secondary side holding member 42, and the secondary side shaft 32 in the valve chamber 25 so as to be displaceable in the axial direction A1.

[0021] 1 and 4, the nozzle 5 is a tubular (i.e. hollow) member having a primary side opening 51 and a secondary side opening 52 having a diameter larger than that of the primary side opening 51. A hollow portion in the nozzle 5 that connects the primary side opening 51 and the secondary side opening 52 is called an "internal flow path" and is given the symbol "5a." The nozzle 5 is disposed on the secondary side of the valve body 3, and the primary side opening 51 opens in the direction of the axis A1 and toward the valve body 3. More specifically, the nozzle 5 is disposed coaxially with the axis A1.

[0022] Although details will be described later, the nozzle 5 increases the flow velocity (fluid force) of a portion of the fluid flowing in the reverse direction from the secondary side to the primary side and then ejects it from the primary side opening 51 toward the valve body 3, thereby promoting the displacement of the valve body 3 in the valve closing direction (i.e., toward the primary side). In particular, in this embodiment, the nozzle 5 is arranged coaxially with the axis A1 and on the secondary side of the secondary side shaft 32 so that the primary side opening 51 opens toward the end face 32a of the secondary side shaft 32. With this arrangement, the fluid ejected from the primary side opening 51 through the nozzle 5 hits the end face 32a, and a force in the valve closing direction acts on the valve body 3 via the secondary side shaft 32. The check valve 100 does not substantially have any mechanism other than the nozzle 5 that biases the valve body 3 in the valve closing direction.

[0023] As shown in the figure, the internal flow passage 5a is preferably formed so as to gradually reduce in diameter from the secondary side opening 52 toward the primary side opening 51. By gradually reducing the diameter in this manner, the flow can be efficiently focused. In the figure, the inner wall of the internal flow passage 5a is convex inward, but it may have other shapes. Cross-sectional views of examples of other shapes are shown in Figures 5(a) and (b). The nozzle 55 in Figure 5(a) has an inner wall that is convex outward, and the inner diameter of the nozzle 56 in Figure 5(b) changes linearly from the primary side opening 51 to the secondary side opening 52.

[0024] The ratio of the diameter of the primary side opening 51 to the diameter of the secondary side opening 52 may be set to a degree that can realize the above-mentioned biasing effect. For example, it is preferable that the diameter of the primary side opening 51 is 80% or less, 60% or less, 50% or less, or 40% or less of the diameter of the secondary side opening 52.

[0025] The primary side opening 51, the secondary side opening 52 and the internal flow passage 5a are preferably circular in plan view, but may be replaced with other shapes.

[0026] A flow path through which a fluid can pass is formed around the nozzle 5. In this embodiment, the nozzle 5 is fixed in the outflow hole 22 via a beam portion 53 that crosses the outflow hole 22 in the radial direction.

[0027] 1 and 3, the protrusions 6 are formed on the secondary side wall surface of the valve chamber 25 and function as a limiting member that limits the movement range of the valve element 3 in the valve opening direction. In this embodiment, four protrusions 6 are formed in a cross shape on the secondary side wall surface of the valve chamber 25 and are continuous with the secondary side retaining member 42 on the radially inner side of the valve chamber 25. The fluid can flow out from the valve chamber 25 to the outflow hole 22 through between the protrusions 6.

[0028] (Check valve operation) The operation of the check valve 100 will now be described with reference to FIGS.

[0029] When the pressure on the primary side is higher than the pressure on the secondary side, this pressure difference opens the valve element 3, and the fluid flows in the forward direction from the valve hole 21 to the outlet hole 22, that is, from the primary side to the secondary side, as shown by the arrow in Figure 1.

[0030] On the other hand, when the pressure on the secondary side becomes higher, the fluid flows in the reverse direction from the outlet hole 22 toward the valve chamber 25, as shown by the arrow in Fig. 6. At this time, the flow velocity (fluid force) increases in the flow that has passed through the nozzle 5. This flow acts on the end face 32a of the secondary shaft 32, and can promote the displacement of the valve body in the valve closing direction.

[0031] In the conventional valve, where the biasing mechanism always biases the valve body regardless of its position, the primary pressure must exceed the secondary pressure at least to such an extent that it exceeds the biasing force in order to open the valve. In contrast, in this embodiment, there is no need to counter such a biasing force, so the valve can be opened with a very small pressure difference.

[0032] Conversely, if the check valve 100 does not have any biasing mechanism, even if the pressure on the secondary side becomes greater than the pressure on the primary side, the valve may remain open and a backflow may occur. This is because the fluid bypasses the valve body and flows from the outlet hole 22 to the valve hole 21, making it difficult for a force in the valve closing direction to be applied to the valve body 3. In particular, when the valve body 3 is in the fully open position or is close to the fully open position and is farther from the valve seat 23, the bypass flow rate is also large, making it easier for a backflow to occur. In contrast, in this embodiment, when the pressure on the secondary side becomes greater than the primary side and a flow in the reverse direction occurs, even if the flow rate is small, the nozzle 5 can increase the flow rate (fluid force) and apply it to the valve body 3. As a result, the displacement of the valve body 3 can be promoted, so that the valve can be closed reliably. Particularly in an environment with low gravity or zero gravity, the valve body 3 can be easily moved to the closed position simply by applying the force that initially triggers the displacement of the valve body 3. Therefore, the nozzle 5 is preferably applied to a check valve used in an environment with low gravity or zero gravity.

[0033] As described above, the check valve 100 of this embodiment comprises a valve chamber 25 through which fluid flows from the primary side to the secondary side, a valve hole 21 provided in the valve chamber 25, a valve body 3 arranged on the secondary side of the valve hole 21 and opening and closing the valve hole 21 by displacing in the axial direction of the valve hole 21, and a nozzle 5 arranged on the secondary side of the valve body 3, the nozzle having a primary side opening 51 that opens in the axial direction of the valve hole 21 and toward the valve body 3, and a secondary side opening 52 having a larger diameter than the primary side opening 51.

[0034] In the check valve 100, the nozzle 5 is not involved in the displacement of the valve element 3 while the fluid is flowing from the primary side to the secondary side. Therefore, the check valve 100 requires less force to open compared to conventional technology that has a configuration that constantly biases the valve element in the valve closing direction. On the other hand, when the fluid flows from the secondary side to the primary side, the nozzle 5 increases the flow rate (fluid force), facilitating the displacement of the valve element 3 in the valve closing direction.

[0035] Furthermore, the check valve 100 of this embodiment further includes a secondary-side shaft 32 extending from the valve body 3 to the secondary side, and a secondary-side holding member 42 that holds the secondary-side shaft 32 movably in the displacement direction of the valve body 3, and the primary-side opening 51 is disposed to face the secondary-side end face 32a of the secondary-side shaft 32. As a result, the fluid focused by the nozzle 5 acts on the secondary-side end face 32a, and can bias the valve body 3 via the secondary-side shaft 32.

[0036] 2. Other embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are appropriately performed. In addition, it is also possible to combine the components described in the above embodiment to form a new embodiment. In addition, among the components described in the attached drawings and detailed description, not only components essential for solving the problem but also components that are not essential for solving the problem in order to exemplify the technology may be included. Therefore, the fact that these non-essential components are described in the attached drawings and detailed description should not immediately be taken to mean that these non-essential components are essential.

[0037] For example, this application also discloses the following techniques:

[0038] (1) As long as it can receive the biasing force of the fluid, a shaft having a different end structure may be used in place of the secondary shaft 32.

[0039] 7(a) to 7(d) show cross-sectional views of other examples of the secondary shaft. In the examples shown in FIG. 7(a) and FIG. 7(b), the secondary shaft has a shaft body 32b and enlarged diameter parts 32c and 32d provided at its end (secondary side end of the shaft) and having a larger diameter than the shaft body 32b. By having the enlarged diameter parts, the area of ​​the secondary side end face of the shaft is increased, so that the fluid from the primary side opening 51 of the nozzle 5 is not lost and the biasing force can be reliably transmitted to the valve body 3. In the example of FIG. 7(a), the shaft body 32b and the enlarged diameter part 32c form a T-shaped cross section. In the example of FIG. 7(b), the enlarged diameter part 32d gradually enlarges in diameter from the shaft body 32b toward the end face. The secondary side end face of the enlarged diameter part may be circular in plan view, or may be rectangular or have another polygonal shape.

[0040] In addition, the end surface of the secondary shaft is flat in the above example, but may have a recess. By having a recess, the focused fluid is not lost and the biasing force can be reliably transmitted to the valve body 3. In FIG. 7(c), the secondary shaft does not have an enlarged diameter portion, but has a recess 32e on the end surface. In the example of FIG. 7(d), the secondary shaft has both an enlarged diameter portion 32d and a recess 32h. The enlarged diameter portion 32c and the recess 32h in FIG. 7(a) may be combined. Note that the recess has a substantially hemispherical bottom surface in FIG. 7(c) and FIG. 7(d), but the bottom surface may be flat. In addition, the recess is preferably circular in plan view, but may have a rectangular or other polygonal shape.

[0041] (2) When the primary side opening of the nozzle faces the secondary side end face of the shaft, the diameter of the primary side opening of the nozzle, the diameter of the secondary side end face of the shaft, and the position of the primary side opening of the nozzle relative to the secondary side end face of the shaft should be such that the fluid sprayed from the primary side opening of the nozzle hits the secondary side end face of the shaft, thereby displacing the valve body.

[0042] (3) In the first embodiment, the mechanism for displaceably holding the valve body is exemplified by a secondary side shaft 32 connected to the valve body 3 and a secondary side holding member 42 that movably holds the secondary side shaft 32, but other structures such as a rail may also be applied as such a mechanism.

[0043] (4) In the first embodiment, the shafts 31 and 32 are formed integrally with the valve body. However, a shaft formed separately from the valve body may be attached to the valve body.

[0044] (5) In addition, in the first embodiment, a long, thin plate-like member having a through hole (primary side holding member 41 and secondary side holding member 42) is exemplified as a member that holds the valve body 3 via the shafts 31, 32. However, other structural structures can be adopted as long as a flow path within the casing can be secured.

[0045] (6) In the first embodiment, the radially arranged convex portions 6 are an example of a limiting member that limits the displacement of the valve disc in the valve opening direction to the fully open position, and the shape of the limiting member is not limited to this.

[0046] (7) Any combination of the above-mentioned embodiments is also included in the disclosure of this application. [Industrial Applicability]

[0047] As described above, the technology of the present disclosure is useful for check valves. [Explanation of symbols]

[0048] 100 Check valve 1 Casing 21 Valve hole 22 Outflow hole 23 Valve seat 25 Valve chamber 3 Valve body 31 Primary shaft 32 Secondary shaft 32a Secondary end face of shaft 32b Shaft body 32c, 32d Expanded diameter part 32e, 32h recess 41 Primary side retaining member 42 Secondary retaining member 44, 45 Through holes 5, 55, 56 nozzles 5a Internal flow path 51 Primary side opening 52 Secondary opening 6 Convex

Claims

1. a valve chamber through which a fluid flows from a primary side to a secondary side; a valve hole provided in the valve chamber; a valve body disposed on a secondary side of the valve hole and adapted to open and close the valve hole by being displaced in an axial direction of the valve hole; a nozzle having a primary side opening that opens in the axial direction of the valve hole and toward the valve body, and a secondary side opening having a diameter larger than that of the primary side opening, the nozzle being disposed on the secondary side of the valve body; A check valve comprising:

2. 2. The check valve according to claim 1, A shaft extending from the valve body to a secondary side; a holding portion that holds the shaft so as to be movable in the displacement direction of the valve body, The shaft is disposed so that the primary side opening faces a secondary side end surface of the shaft. non-return valve.

3. 3. The check valve according to claim 2, The shaft has a shaft body extending from the valve body to the secondary side, and an expanded diameter portion provided at a secondary side end of the shaft body and having a larger diameter than the shaft body, The nozzle is disposed so that the primary side opening faces the secondary side end surface of the expanded diameter portion. non-return valve.

4. The check valve according to claim 2 or 3, The shaft has a recess on the secondary end surface. non-return valve.

Images