non-return valve

Abstract

To provide a check valve enabling a valve element to more largely receive pressure of fluid and thus efficiently move when the valve element is closed while appropriately securing a flow rate of the fluid when the valve element is in an opened state.SOLUTION: A check valve 10 includes: a flow passage part 20 having a small diameter part 21 and a large diameter part 22; and a valve element 30 having a contact / separation part 31 capable of coming into contact with / separating from a valve seat 21a. The check valve also includes: a first hole 22a; a second hole 22b having a diameter larger than that of the first hole 22a; a closing plate part 32 having an area that approximately closes the first hole 22a; and a connecting part 33 of which area in a direction orthogonal to a flow passage direction R is smaller than that of the closing plate part 32 and that connects the closed plate part 32 and the contact / separation part 31 to each other. The closed plate part 32 secures a flow passage with respect to the second hole 22b when located in the second hole 22b, and when the valve element 30 moves to the upstream side and then moves into the first hole 22a on the basis of a pressure difference between the upstream side and the downstream side of the valve element 30, the closed plate part approximately closes the first hole 22a before the contact / separation part 31 and the valve seat 21a come in contact with each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a check valve. [Background technology]

[0002] Patent Document 1 discloses a configuration in which an LP gas container and a collecting pipe are connected by a high-pressure hose and a check valve. This check valve has a valve seat on the LP gas container side and a valve body on the collecting pipe side. When the LP gas container is empty and the pressure on the collecting pipe side of the check valve becomes higher than the pressure on the LP gas container side by a predetermined pressure or more, the valve body comes into contact with the valve seat in the check valve to close the valve, preventing the backflow of LP gas from the collecting pipe side to the LP gas container side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-252565 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a check valve such as that described in Patent Document 1, it is desirable that the valve element be able to move efficiently by appropriately receiving the pressure of LP gas from the collecting pipe side when the valve is closed. Also, it is desirable that the valve element be able to appropriately ensure the flow rate of fluid such as LP gas from the LP gas container side to the collecting pipe side when the valve is open, such as during normal LP gas supply.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a check valve which ensures an appropriate flow rate of fluid when the valve body is open, while allowing the valve body to receive greater fluid pressure and move efficiently when it is closed. [Means for solving the problem]

[0006] The check valve according to the present invention comprises a flow path portion through which a fluid flows, the flow path portion having a small diameter portion having a valve seat, and a large diameter portion provided downstream of the small diameter portion and having a diameter larger than that of the small diameter portion, a valve body having a contact portion movable within the large diameter portion along a flow path direction and capable of contacting and separating from the valve seat, and a biasing means for biasing the valve body downstream, wherein when a pressure downstream of the valve body becomes higher than a pressure upstream of the valve body by a predetermined pressure or more, the valve body moves upstream against the biasing force of the biasing means, and the contact portion comes into contact with the valve seat, thereby preventing a backflow of a fluid. The valve body has a second hole that is located downstream of the first hole and has a larger diameter than the first hole, a blocking plate portion that is formed in the valve body and has an area that substantially blocks the first hole and is movable between the first hole and the second hole, and a connecting portion that is formed in the valve body and has an area smaller than that of the blocking plate portion along a direction perpendicular to the flow path direction and connects the blocking plate portion and the contact and separation portion, wherein the blocking plate portion secures a flow path between the second hole when positioned at the second hole, and when the valve body moves upstream into the first hole based on a pressure difference between the upstream and downstream sides of the valve body, the blocking plate portion substantially blocks the first hole before the contact and separation portion comes into contact with the valve seat. Effect of the Invention

[0007] According to the present invention, an appropriate flow rate of fluid is ensured when the valve disc is open, while when the valve disc is closed, the valve disc is subjected to a greater pressure of the fluid and can move efficiently. [Brief description of the drawings]

[0008] [Figure 1] 1A is a configuration diagram of an LP gas supply system including a check valve according to a first embodiment of the present invention, FIG. 1B is an external view showing the details of the check valve shown in FIG. 1A, and FIG. 1C is a cross-sectional view taken along line AA in FIG. 1B. [Diagram 2] 1A is a schematic perspective view showing an outline of a check valve, and FIG. 1B is a diagram showing the pressure of LP gas acting on the check valve in the configuration of FIG. [Diagram 3]1A is a schematic perspective view showing the state in which the closure plate portion of the check valve slides in the first hole, as viewed from the longitudinal cross-sectional side, and FIG. 1B is a schematic perspective view showing the state in which the closure plate portion of the check valve slides in the first hole, as viewed from the downstream side. [Figure 4] 1A is a schematic perspective view showing the state in which the valve body moves further upstream, the contact portion comes into contact with the valve seat, and the second sliding plate portion moves toward the step portion, as viewed from the vertical cross-sectional side, and FIG. 1B is a schematic perspective view showing the state in which the valve body moves further upstream, and the second sliding plate portion moves toward the step portion, as viewed from the downstream side. [Diagram 5] 1(a) is a schematic perspective view showing the configuration of a check valve according to Comparative Example 1. FIG. 1(b) is a schematic perspective view showing the configuration of a check valve according to Comparative Example 2. [Figure 6] 1A is a graph comparing the pressure applied to the valve element from the downstream side with the pressure equivalent to the repulsive force of the spring for the check valve of Comparative Example 1. FIG. 1B is a graph comparing the pressure applied to the valve element from the downstream side with the pressure equivalent to the repulsive force of the spring for the check valve of Comparative Example 2. FIG. 1C is a graph comparing the pressure applied to the valve element from the downstream side with the pressure equivalent to the repulsive force of the spring for the check valve according to the first embodiment of the present invention. [Figure 7] 1(a) is a schematic perspective view showing a state in which the closure plate portion of the check valve according to the second embodiment of the present invention slides in the first hole and the second sliding plate portion moves toward the step portion, and FIG. 1(b) is a schematic perspective view showing a state in which the closure plate portion of the check valve according to the modified example of the present invention slides in the first hole and the second sliding plate portion moves toward the step portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be modified as appropriate within the scope of the present invention. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but for the details of the omitted technologies, publicly known or well-known technologies are applied as appropriate within the scope of not causing any contradiction with the contents described below.

[0010] (First embodiment) Fig. 1(a) is a configuration diagram of an LP gas supply system 1 including a check valve 10 according to a first embodiment of the present invention. As shown in Fig. 1(a), the LP gas supply system 1 includes a plurality of LP gas containers 51, 52, 53, 54, a collecting pipe 60, an automatic switching regulator 70, and the check valve 10.

[0011] The LP gas containers 51, 52, 53, and 54 are containers that contain LP gas (fluid) and supply the LP gas to consumers (for example, individual homes). The collecting pipe 60 is a pipe that collects the LP gas from the LP gas containers 51, 52, 53, and 54.

[0012] The automatic switching regulator 70 is disposed on the collecting pipe 60 and is connected to each home via an outlet port. This automatic switching regulator 70 is disposed in the center of the collecting pipe 60, and switches between the left and right collecting pipes 60 (LP gas containers 51, 52 and LP gas containers 53, 54), and reduces the pressure of the LP gas using a pressure adjustment function to adjust it to the pressure that is sent to the home.

[0013] The check valve 10 is a valve arranged between each LP gas container 51, 52, 53, 54 and the collecting pipe 60, and more specifically, is arranged between the high-pressure hose 80 extending from the opening / closing valve 55 of each LP gas container 51, 52, 53, 54 and the collecting pipe 60.

[0014] In the example shown in FIG. 1(a), the LP gas supply system 1 includes four LP gas containers 51, 52, 53, 54, but is not limited to four, and may include three or less, or five or more.

[0015] FIG. 1(b) is an external view showing the details of the check valve 10 shown in FIG. 1(a). FIG. 1(c) is a cross-sectional view taken along line AA in (b). As shown in FIG. 1(b) and FIG. 1(c), the check valve 10 includes a flow path portion 20. A lever 96 is attached to the flow path portion 20. An operator operates the lever 96 to open a ball valve 97 shown in FIG. 1(c) to allow LP gas to pass, and close the ball valve 97 to stop the flow of LP gas. After closing the ball valve 97, the operator replaces the LP gas containers 51, 52, 53, and 54.

[0016] FIG. 2(a) is a schematic perspective view showing an outline of the check valve 10. The check valve 10 includes a flow path portion 20, a valve body 30, a spring 40 (biasing means), and a movement limiting portion 45. In the following description, the downstream side refers to the collecting pipe 60 side as viewed from the LP gas containers 51, 52, 53, and 54. The upstream side refers to the LP gas containers 51, 52, 53, and 54 side as viewed from the collecting pipe 60. The flow path direction R is a direction along the flow path portion 20, and includes both a direction from the downstream side toward the upstream side and a direction from the upstream side toward the downstream side. In the check valve 10, the valve body 30 is configured to move in the flow path direction R inside the flow path portion 20. Details will be specifically described below.

[0017] The flow path 20 is a portion through which the LP gas flows, and has a small diameter portion 21 and a large diameter portion 22. The small diameter portion 21 has a valve seat 21a and a small diameter hole 21b. The valve seat 21a is formed at the downstream end of the small diameter hole 21b, and is diverged toward the downstream side.

[0018] Large diameter portion 22 is provided downstream of small diameter portion 21 and is formed to have a larger diameter than small diameter portion 21. Large diameter portion 22 has a first hole 22a, a second hole 22b, and a step portion 22c.

[0019] The first hole 22a is formed in the large diameter portion 22 and has a first diameter L1. The second hole 22b is formed in the large diameter portion 22 and is located downstream of the first hole 22a and has a second diameter L2 larger than the diameter of the first hole 22a. The step portion 22c is a step portion formed between the first hole 22a and the second hole 22b.

[0020] The valve body 30 has a contact and separation portion 31, a blocking plate portion 32, a connection portion 33, and an extension portion 34. The contact and separation portion 31 is a portion that is movable within the large diameter portion 22 along the flow path direction R and can contact and separate from the valve seat 21a. The contact and separation portion 31 is constituted by an annular packing formed of an elastic member such as rubber. The contact and separation portion 31 contacts the valve seat 21a to close the small diameter portion 21 and stop the flow of LP gas. When the contact and separation portion 31 is away from the valve seat 21a, it opens the gap between the small diameter portion 21 and the large diameter portion 22, allowing the LP gas to flow.

[0021] The closure plate portion 32 is a portion formed on the valve body 30, has an area that substantially blocks the first hole 22a, and is movable within the first hole 22a and the second hole 22b. When the closure plate portion 32 is positioned within the first hole 22a, the closure plate portion 32 substantially blocks the first hole 22a. In this case, substantially blocking refers to, for example, a state in which 75% or more of the cross-sectional area of ​​the first hole 22a is blocked, and preferably a state in which 95% or more of the cross-sectional area of ​​the first hole 22a is blocked. When the closure plate portion 32 is positioned within the second hole 22b, the closure plate portion 32 opens the first hole 22a.

[0022] The connection portion 33 is a portion formed on the valve body 30, and connects between the contact and separation portion 31 and the closure plate portion 32. The connection portion 33 has a plurality of plate-shaped first sliding plate portions 33m and an insertion protrusion portion 33n.

[0023] The first sliding plate portions 33m extend in four radial directions from the center of the first hole 22a. The first sliding plate portions 33m extend from the closure plate portion 32 toward the upstream side. The first sliding plate portions 33m are arranged adjacent to each other in the circumferential direction and intersect with each other at an angle of 90°. There is a gap between the first sliding plate portions 33m adjacent in the circumferential direction. The radial ends of the first sliding plate portions 33m slide in the first hole 22a when the valve body 30 moves along the flow path direction R.

[0024] The insertion protrusion 33n protrudes from the first sliding plate portion 33m toward the upstream side, and the aforementioned contact and separation portion 31 is attached to the insertion protrusion 33n. The insertion protrusion 33n has a first insertion protrusion 33n1 and a second insertion protrusion 33n2. The first insertion protrusion 33n1 is a portion located on the center side when the valve body 30 is viewed from the upstream side, and the second insertion protrusion 33n2 is a portion located on the outer periphery side of the first insertion protrusion 33n1 when the valve body 30 is viewed from the upstream side. The second insertion protrusion 33n2 has a smaller radial dimension than the first sliding plate portion 33m, and is formed continuously from the first sliding plate portion 33m to the upstream side.

[0025] The extension portion 34 is a portion formed on the valve body 30 and extended downstream from the closure plate portion 32. The extension portion 34 has a plurality of plate-shaped extension sliding portions 34n and a plurality of plate-shaped second sliding plate portions 34m.

[0026] The extension sliding portion 34n extends in four radial directions from the center of the first hole 22a and the second hole 22b. The extension sliding portion 34n also extends from the closure plate portion 32 toward the downstream side. The extension sliding portions 34n are arranged adjacent to each other in the circumferential direction and intersect with each other at an angle of 90°. There is a gap between the extension sliding portions 34n adjacent to each other in the circumferential direction. The diameter of the extension sliding portion 34n is the first diameter L1, similar to the first sliding plate portion 33m. The radial end of the extension sliding portion 34n slides against the first hole 22a when the valve body 30 moves along the flow path direction R. The radial end of the extension sliding portion 34n faces the second hole 22b when the valve body 30 moves along the flow path direction R.

[0027] The second sliding plate portions 34m extend in four radial directions from the center of the second hole 22b. The second sliding plate portions 34m also extend downstream from the extended sliding portion 34n. The second sliding plate portions 34m are arranged adjacent to each other in the circumferential direction and intersect with each other at an angle of 90°. There is a gap between the second sliding plate portions 34m adjacent in the circumferential direction. The radial ends of the second sliding plate portions 34m slide in the second hole 22b when the valve body 30 moves along the flow path direction R.

[0028] The spring 40 biases the valve body 30 downstream. For example, one end of the spring 40 contacts the upstream end 23 of the first hole 22a, and the other end of the spring 40 contacts the upstream end 33m1 of the first sliding plate portion 33m, and the spring 40 is interposed in a compressed state.

[0029] The movement limiting portion 45 limits the valve body 30 from moving too far downstream due to the biasing force of the spring 40 .

[0030] Next, the operation of the check valve 10 according to this embodiment will be described with reference to Figs. 2, 3, and 4. In addition, a case where an LP gas container 51 is connected to the high pressure hose 80 upstream of the check valve 10 will be described as an example. First, in the above-mentioned configuration, it is assumed that the pressure of the LP gas upstream of the valve body 30 is higher than the pressure of the LP gas downstream of the valve body 30. In this case, as shown in Fig. 2(a), the valve body 30 moves downstream and contacts the movement limiting portion 45. At this time, the blocking plate portion 32 is located downstream of the step portion 22c in the second hole 22b. When the blocking plate portion 32 is located in the second hole 22b, a flow path is secured between the blocking plate portion 32 and the second hole 22b.

[0031] LP gas is supplied from an LP gas container 51 (see FIG. 1(a)) and passes through the small diameter portion 21, the first hole 22a, the gaps between the first sliding plate portions 33m, and the gaps between the closure plate portion 32 and the second hole 22b, in that order, as shown by the dotted arrow in FIG. 2(a). The LP gas then passes through the gaps between the extension sliding portions 34n and the gaps between the second sliding plate portions 34m, in that order, and heads toward the collecting pipe 60 (see FIG. 1(a)).

[0032] Next, for example, suppose that the LP gas container 51 (see FIG. 1(a)) is emptied and removed from the high-pressure hose 80. The pressure applied from the downstream side of the valve body 30 becomes higher than the pressure applied from the upstream side of the valve body 30 (including the repulsive force of the spring 40) (see FIG. 2(a)). In this case, as shown in FIG. 2(b), the LP gas pressure is applied from the downstream side to the closure plate portion 32 and the step portion 22c beyond the gap between the closure plate portion 32 and the second hole 22b. For this reason, not all of the LP gas pressure is applied to the closure plate portion 32, and part of the LP gas pressure escapes to the step portion 22c.

[0033] Fig. 3(a) is a schematic perspective view showing the closure plate portion 32 of the check valve 10 sliding in the first hole 22a, as viewed from the vertical cross section side. Fig. 3(b) is a schematic perspective view showing the closure plate portion 32 of the check valve 10 sliding in the first hole 22a, as viewed from the downstream side.

[0034] In the process of transition from the state of FIG. 2(b) to the state of FIG. 3(a) and FIG. 3(b), the closing plate portion 32 moves a predetermined distance upstream against the biasing force of the spring 40 based on the pressure difference between the upstream side and the downstream side of the valve body 30, and moves into the first hole 22a. Then, as shown in FIG. 3(a) and FIG. 3(b), the closing plate portion 32 substantially closes the first hole 22a before the contact portion 31 and the valve seat 21a come into contact. When the closing plate portion 32 is located in the first hole 22a, the LP gas hits the closing plate portion 32 and has no place to escape, and the closing plate portion 32 receives the pressure of the LP gas without leaving any residue. For this reason, the closing plate portion 32 is difficult to move upstream before the closing plate portion 32 enters the first hole 22a, and is easy to move upstream after entering the first hole 22a. In other words, the pressure received when the closure plate portion 32 is positioned at the first hole 22a is greater than the pressure received when the closure plate portion 32 is positioned at the second hole 22b.

[0035] Then, the closure plate 32 moves upstream under the pressure of the LP gas. At this time, the first sliding plate 33m slides against the first hole 22a, while the second sliding plate 34m slides against the second hole 22b, so that the closure plate 32 moves upstream while preventing axial misalignment.

[0036] Fig. 4(a) is a schematic perspective view showing the state where the valve body 30 moves further upstream, the contact portion 31 comes into contact with the valve seat 21a, and the second sliding plate portion 34m moves toward the step portion 22c, as viewed from the vertical cross section side. Fig. 4(b) is a schematic perspective view showing the state where the valve body 30 moves further upstream, and the second sliding plate portion 34m moves toward the step portion 22c, as viewed from the downstream side. As shown in Figs. 4(a) and 4(b), when the valve body 30 moves further upstream, the contact portion 31 comes into contact with the valve seat 21a to prevent backflow of LP gas when in the valve closed position.

[0037] Fig. 5(a) is a schematic perspective view showing the configuration of a check valve 100 according to Comparative Example 1. In the check valve 100 shown in Fig. 5(a), the large diameter portion 22 of the flow path portion 20 has the first hole 22a but does not have the second hole 22b, and the connecting portion 133 of the valve body 130 has the first sliding plate portion 33m but does not have the blocking plate portion 32. For this reason, the area that blocks the first hole 22a by only the first sliding plate portion 33m of the check valve 100 is small, and the check valve 100 cannot receive a large pressure of the LP gas flowing upstream.

[0038] 6(a) is a graph comparing the pressure applied to the valve element 130 from the downstream side with the pressure equivalent to the repulsive force of the spring 40 for the check valve 100 according to Comparative Example 1. A solid line M1 indicates the pressure applied to the valve element 130 from the downstream side versus the moving distance of the valve element 130. A dotted line N indicates the pressure equivalent to the repulsive force of the spring 40 versus the moving distance of the valve element 130 (the pressure obtained by dividing the repulsive force of the spring 40 by the area of ​​the first hole 22a).

[0039] As described with reference to Fig. 5(a), the valve body 130 of Comparative Example 1 cannot efficiently receive the pressure of the LP gas from the downstream side. Therefore, as shown in Fig. 6(a), in addition to the pressure equivalent to the repulsive force of the spring 40, a relatively large pressure Y1 is required to reach the valve closed position.

[0040] Fig. 5(b) is a schematic perspective view showing the configuration of a check valve 200 according to Comparative Example 2. In the check valve 200 shown in Fig. 5(b), the large diameter portion 22 of the flow path portion 20 has the first hole 22a but does not have the second hole 22b, and the valve body 230 has an obstruction body 233m as a connecting portion instead of the first sliding plate portion 33m. This obstruction body 233m largely blocks the flow path of the first hole 22a, and therefore can receive a large pressure of the LP gas flowing upstream.

[0041] 6(b) is a graph comparing the pressure applied to the valve element 230 from the downstream side with the pressure equivalent to the repulsive force of the spring 40 for the check valve 200 according to Comparative Example 2. A solid line M2 indicates the pressure applied to the valve element 230 from the downstream side versus the moving distance of the valve element 230. A dotted line N indicates the pressure equivalent to the repulsive force of the spring 40 versus the moving distance of the valve element 230 (the pressure obtained by dividing the repulsive force of the spring 40 by the area of ​​the first hole 22a).

[0042] As described with reference to Fig. 5(b), the valve body 230 of Comparative Example 2 can efficiently receive the pressure of the LP gas from the downstream side. It is only necessary to add a relatively small pressure Y2 to the pressure equivalent to the repulsive force of the spring 40 to reach the valve closed position. This shows that the check valve 200 of Comparative Example 2 closes at a smaller pressure than the check valve 100 of Comparative Example 1.

[0043] However, in the check valve 200 of comparison example 2, the space through which the LP gas passes between the obstruction body 233m of the check valve 200 and the first hole 22a is small, so the flow of LP gas from the LP gas containers 51-54 (see Figure 1(a)) to the collecting pipe 60 (see Figure 1(a)) is obstructed.

[0044] 6(c) is a graph comparing the pressure applied to the valve element 30 from the downstream side with the pressure equivalent to the repulsive force of the spring 40 for the check valve 10 according to the first embodiment of the present invention. The solid line M3 shows the pressure applied to the valve element 30 from the downstream side versus the moving distance of the valve element 30. The dotted line N shows the pressure equivalent to the repulsive force of the spring 40 versus the moving distance of the valve element 30.

[0045] In the check valve 10 of the first embodiment, the closure plate portion 32 receives the pressure of LP gas within the second hole 22b, so that the pressure required is smaller than that in the comparative example 1 up to the position where the closure plate portion 32 projects into the first hole 22a.

[0046] After the closure plate portion 32 enters the first hole 22a, the rate of increase in pressure of the check valve 10 of the first embodiment is similar to that of the spring 40. That is, the check valve 10 of the first embodiment requires pressure Y3 to reach the valve closed position in addition to the pressure equivalent to the repulsive force of the spring 40. This pressure Y3 is smaller than the pressure Y1 of Comparative Example 1 and the pressure Y2 of Comparative Example 2. From this, it can be seen that the check valve 10 of the first embodiment closes at a pressure smaller than the check valve 100 of Comparative Example 1 and the check valve 200 of Comparative Example 2.

[0047] According to the configuration of the check valve 10 of the first embodiment described above, the area of ​​the connecting portion 33 along the direction perpendicular to the flow path direction R is smaller than that of the closing plate portion 32. Therefore, when the valve body 30 is open, an appropriate flow rate of LP gas is ensured. When the closing plate portion 32 is located in the second hole 22b, LP gas flows downstream between the multiple first sliding plate portions 33m, between the closing plate portion 32 and the second hole 22b, and between the second sliding plate portions 34m, so that the flow rate of LP gas downstream is ensured.

[0048] The area of ​​the closure plate portion 32 is large enough to substantially close the first hole 22a. A configuration having the closure plate portion 32 can withstand the pressure of the LP gas more easily than a configuration not having the closure plate portion 32. Therefore, when the valve body 30 closes, the valve body 30 receives a larger pressure of the LP gas and can move efficiently.

[0049] In the above-mentioned comparative example 1, the valve body 130 cannot withstand a large pressure. Therefore, it is necessary to use a spring 40 with a small force. However, in this embodiment, the valve body 30 can withstand a large pressure. Therefore, it is possible to operate even if a spring 40 with a large force is used. Furthermore, when configured to operate with the same pressure as before, the urging force of the spring 40 can be set larger than before, so the durability of the spring 40 is improved. Furthermore, when the same spring 40 as before is used, the movement of the valve body 30 can be set larger, so malfunctions are suppressed.

[0050] The connecting portion 33 of the check valve 10 has a plurality of plate-like first sliding plate portions 33m that are provided between the blocking plate portion 32 and the contact portion 31, extend radially from the center of the first hole 22a, and slide on the first hole 22a when the valve body 30 moves along the flow path direction R. Therefore, a large gap through which the LP gas flows is secured between the first sliding plate portions 33m. As a result, the flow path of the LP gas from the first hole 22a to the second hole 22b is secured, and the axial misalignment of the valve body 30 is suppressed.

[0051] The connection portion 33 of the check valve 10 has a plurality of plate-like second sliding plate portions 34m that are provided downstream of the blocking plate portion 32, extend radially from the center of the second hole 22b, and slide against the second hole 22b when the valve body 30 moves along the flow path direction R. Therefore, in addition to the sliding points between the first sliding plate portions 33m and the first hole 22a, sliding points between the second sliding plate portions 34m and the second hole 22b are secured. As a result, axial misalignment of the valve body 30 is suppressed.

[0052] Second embodiment Fig. 7(a) is a schematic perspective view showing a state in which the closure plate portion 32 of the check valve 11 according to the second embodiment of the present invention slides in the first hole 22a and the second sliding plate portion 34m moves toward the step portion 22c. As shown in Fig. 7(a), in the check valve 11, the closure plate portion 32 has a plate-side recess 101 that is recessed in a direction away from the first hole 22a so as to form a gap between the closure plate portion 32 and the first hole 22a when the closure plate portion 32 is located at the first hole 22a.

[0053] According to this configuration, the closure plate 32 forms a gap with the first hole 22a, so it is less likely to react to a slight pressure difference between the first hole 22a and the second hole 22b than in a configuration where no gap is formed with the first hole 22a. This prevents the valve body 30 from malfunctioning.

[0054] In particular, when a check valve is used near the automatic switching regulator 70, the vibration of the automatic switching regulator 70 may cause the valve element of the check valve to vibrate, or a pressure difference may occur due to a temperature difference in the piping before and after the check valve, so the valve element may operate to some extent even if it is not completely closed. If the flow path is completely blocked without having the plate-side recess 101 as described above, all of the pressure is converted into the movement of the valve element, making it easy for the valve element to malfunction.

[0055] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and modifications may be made without departing from the spirit of the present invention, and other technologies may be appropriately combined to the extent possible.

[0056] FIG. 7(b) is a schematic perspective view showing a state in which the closure plate portion 32 of the check valve 12 according to the modified example of the present invention slides in the first hole 22a and the second sliding plate portion 34m moves toward the step portion 22c. As shown in FIG. 7(a), in the check valve 11, the closure plate portion 32 has a plate-side recess 101 that forms a gap between the closure plate portion 32 and the first hole 22a and is recessed in a direction away from the first hole 22a, but this is not limited to the above. For example, as shown in FIG. 7(b), the first hole 22a of the flow path portion 20 may have a flow path-side recess 102 that is recessed in a direction away from the closure plate portion 32 so as to form a gap between the closure plate portion 32 and the closure plate portion 32 when the closure plate portion 32 is located inside. Alternatively, the check valve may have both the plate-side recess 101 of FIG. 7(a) and the flow path-side recess 102 of FIG. 7(b).

[0057] In the above-described embodiment, the check valve 10 is provided in the collecting pipe 60, but this is not limiting. For example, at the connection between the automatic switching regulator 70 and the high-pressure hose 80, the check valve 10 may be provided on the automatic switching regulator 70 side or on the high-pressure hose 80 side. Alternatively, the check valve 10 may be provided at another location in the LP gas supply system 1. Alternatively, the check valve 10 may be applied in a form in which it is built into a configuration in which the collecting pipe 60 and the check valve 10 in FIG. 1(a) are integrated together.

[0058] In the above embodiment, the first sliding plate portion 33m, the extended sliding portion 34n, and the second sliding plate portion 34m are configured to extend in the radial direction in four pieces, but this is not limited to this. The first sliding plate portion 33m, the extended sliding portion 34n, and the second sliding plate portion 34m may be configured to extend in the radial direction in a number other than four pieces, such as two, three, or five pieces.

[0059] In the above embodiment, the contact portion 31 is described as an "annular packing", but this is not limited thereto. For example, the contact portion 31 may be a flat rubber valve capable of closing the small diameter portion 21. [Explanation of symbols]

[0060] 1: LP gas supply system 10, 11, 12: Check valve 20: Flow path section 21: Small diameter part 21a: Valve seat 21b: Small diameter hole 22: Large diameter section 22a: 1st hole 22b: 2nd hole 22c: Step 23: End 30: Valve body 31: Contact section 32:Occluded plate part 33:Connection part 33m: First sliding plate section 33m1: Upstream end 33n: Insertion protrusion 33n1: First insertion protrusion 33n2: Second insertion protrusion 34 :Extension part 34m: Second sliding plate section 34n: Extended sliding part 40: Spring (biasing means) 45: Movement restriction section 51, 52, 53, 54: LP gas cylinders 55: Opening and closing valve 60: Collecting pipe 70: Automatic switching regulator 80: High pressure hose 96: Lever 97: Ball valve 101: Plate side recess 102: Flow passage side recess L1: 1st diameter L2: Second diameter R: Flow direction

Claims

1. a valve body having a contact portion that is movable within the large diameter portion along the flow path direction and can contact and separate from the valve seat; and a biasing means for biasing the valve body downstream, wherein when the pressure downstream of the valve body becomes higher than the pressure upstream of the valve body by a predetermined pressure or more, the valve body moves upstream against the biasing force of the biasing means, and the contact portion comes into contact with the valve seat, thereby preventing backflow of the fluid, A first hole formed in the large diameter portion; a second hole formed in the large diameter portion, the second hole being disposed downstream of the first hole and having a larger diameter than the first hole; a closing plate portion formed on the valve body, the closing plate portion having an area that substantially closes the first hole, and capable of moving between the first hole and the second hole; a connecting portion formed on the valve body, the connecting portion having an area smaller than that of the closing plate portion along a direction perpendicular to the flow path direction, the connecting portion connecting the closing plate portion and the contact portion; Equipped with The closure plate portion is a flow path is secured between the second hole and the electrode when the electrode is located in the second hole; When the valve disc moves upstream into the first hole based on a pressure difference between the upstream side and the downstream side of the valve disc, the first hole is substantially closed before the contact portion comes into contact with the valve seat. A check valve characterized by:

2. The check valve as described in claim 1, characterized in that the closure plate portion has a plate side recess that is recessed in a direction away from the first hole so as to form a gap between the closure plate portion and the first hole when the closure plate portion is positioned at the first hole.

3. A check valve as described in claim 1 or claim 2, characterized in that the first hole has a flow path side recess that is recessed in a direction away from the closure plate portion so as to form a gap between the closure plate portion and the first hole when the closure plate portion is positioned inside the first hole.

4. 4. The check valve according to claim 1, wherein the connecting portion has a plurality of plate-shaped first sliding plate portions extending radially from a center of the first hole and sliding against the first hole when the valve body moves along the flow path direction.

5. The check valve as described in claim 4, characterized in that it is provided with a plurality of plate-shaped second sliding plate portions that are provided downstream of the closure plate portion, extend radially from the center of the second hole, and slide against the second hole when the valve body moves along the flow path direction.

Images