Diaphragm valve element and diaphragm valve

Abstract

The present invention circumvents a rapid pressure rise due to hydraulic shock while making it possible to maintain a good closed state.　The present invention comprises: a contact part 24a which is brought into contact with a valve seat; a deformation part 24b which is elastically deformed during opening and closing; and a plate-shaped part 25 which is formed from a material having a higher hardness than the contact part 24a and the deformation part 24b, and to which the contact part 24a and the deformation part 24b are attached. The plate-shaped part 25 is provided with a protruding part 25a that is inserted into a cylindrical part, the tip of which is provided with the valve seat. The contact part 24a is provided with an insertion hole 24ha through which the protruding part 25a can be inserted, and an annular projection 24p that surrounds the insertion hole 24ha, has a diameter smaller than the inner diameter of the cylindrical part, and projects in the seating direction of the contact part 24a with respect to the valve seat. The annular projection 24p has a projection length defined such that the insertion length into the cylindrical part when the contact part 24a is seated on the valve seat is shorter than the insertion length of the protruding part 25a into the cylindrical part.

Description

Diaphragm valve body and diaphragm valve

[0001] The present invention relates to a diaphragm valve body including a contact portion that is brought into contact with a valve seat in a closed state, a deformation portion that is elastically deformed during an opening / closing operation, and a mounting portion to which the contact portion and the deformation portion are attached, and a diaphragm valve configured with such a diaphragm valve body.

[0002] The applicant has disclosed in the following patent documents a solenoid valve configured to regulate / permit the passage of tap water by including a main valve and a pilot valve.

[0003] In this case, in the solenoid valve disclosed by the applicant, the above-mentioned main valve is composed of a diaphragm valve, and a contact portion that is brought into contact with a valve port (valve seat) in a closed state and a deformation portion that is elastically deformed during an opening / closing operation are integrally formed with an elastic resin to form a valve film portion, and the valve film portion is attached to a main body portion (mounting portion) formed of a material having a higher hardness than the valve film portion and integrated, whereby a valve body (diaphragm valve body) is formed. Further, in the solenoid valve disclosed by the applicant, the above-mentioned pilot valve is configured such that the valve body is brought into contact with a small hole provided in a casing (a hole that communicates a downstream space and a pressure chamber in a flow path of tap water), and the small hole is opened and closed by moving the valve body away from and towards an actuator (electromagnet).

[0004] In this solenoid valve, when the valve body of the pilot valve is brought into contact with the above-mentioned small hole provided in the casing and the small hole is blocked, tap water flows from an upstream space in the flow path of tap water into the pressure chamber through a small hole provided in the valve body of the main valve, whereby the pressure in the upstream space and the pressure in the pressure chamber become substantially equal. In this state, the valve body of the main valve is pressed against the valve port (valve seat) by the biasing force of a spring (closed state), and the passage of tap water is regulated.

[0005] Furthermore, in this solenoid valve, when the valve body of the pilot valve is separated from the aforementioned small hole, tap water in the pressure chamber flows out through the hole into the downstream space, causing the pressure in the pressure chamber to become lower than the pressure in the upstream space. As a result, the valve body of the main valve is separated from the valve port (valve seat) against the biasing force of the spring (open state), allowing tap water to pass from the upstream space to the downstream space. Moreover, in this solenoid valve, when the valve body of the pilot valve is brought into contact with the aforementioned small hole, the outflow of tap water from the pressure chamber to the downstream space is restricted, and tap water flows from the upstream space into the pressure chamber through the small hole in the valve body of the main valve, making the pressure in the upstream space and the pressure in the pressure chamber equal again. As a result, the valve body of the main valve is pressed against the valve port (valve seat) (closed state), restricting the passage of tap water once again.

[0006] Japanese Patent Publication No. 2017-040309 (pages 5-10, Figures 1-7)

[0007] However, the solenoid valve disclosed by the applicant has the following issues that need improvement. Specifically, the solenoid valve disclosed by the applicant employs a configuration in which the pressure inside the pressure chamber is changed by opening and closing a pilot valve, thereby transitioning the main valve from a closed state to an open state, or from an open state to a closed state.

[0008] In this case, with this type of solenoid valve, when the valve is moved to the open state, tap water is allowed to pass between the valve body and valve seat of the main valve from the upstream space to the downstream space. Therefore, in the open state, it is necessary to keep the valve body sufficiently separated from the valve seat so as not to obstruct the passage of tap water. On the other hand, when moving from the open state to the closed state, it is preferable to stop the outflow of tap water into the downstream space without delay. For this reason, the above-mentioned solenoid valve is equipped with a spring that biases the valve body of the main valve toward the valve seat (valve opening), and when the pressure in the pressure chamber becomes approximately equal to the pressure in the upstream space, the valve body of the main valve can smoothly come into contact with (seat) the valve seat and move to the closed state.

[0009] However, when the valve is transitioned from the open state to the closed state too quickly, the tap water moving through the flow path is abruptly stopped at the main valve, causing a water hammer phenomenon in which the pressure in the upstream space rises sharply. When this water hammer phenomenon causes an excessive pressure rise, there is a risk that the solenoid valve (main valve) may be damaged or that water leakage may occur in the piping upstream of the solenoid valve. For this reason, the applicant attempted to mitigate the rapid pressure rise caused by the water hammer phenomenon by using a spring with a weaker biasing force that biases the valve body of the main valve toward the valve seat, thereby increasing the time required for the valve body to contact the valve seat during the transition from the open state to the closed state (when the pressure in the pressure chamber rises). However, in a configuration using a spring with a weak biasing force, there is a risk that the pressing force of the valve body toward the valve seat in the closed state will be insufficient, making it difficult to maintain the closed state properly. Furthermore, some types of diaphragm valves lack a spring to bias the valve body, and in such valves, it is not even possible to adjust the force that tries to push the valve body toward the valve seat by changing the biasing force of the spring.

[0010] This invention has been made in view of the aforementioned problems that need to be improved, and its main objective is to provide a diaphragm valve body and a diaphragm valve that can maintain a good closed state while suitably avoiding a rapid pressure rise due to the water hammer phenomenon.

[0011] To achieve the above objective, the diaphragm valve body according to claim 1 restricts the passage of fluid in a closed state, where it is seated against a valve seat provided at the tip of a cylindrical portion that forms a fluid passage, and allows the passage of fluid in an open state, where it is separated from the valve seat, comprising: a contact portion that contacts the valve seat in the closed state; a deformable portion that is elastically deformed when transitioning from the open state to the closed state and when transitioning from the closed state to the open state; and a material formed of a higher hardness than the contact portion and the deformable portion. The device comprises a contact portion and a mounting portion to which the deformed portion is attached, the mounting portion is provided with a convex portion that is inserted into the cylindrical portion, the contact portion is provided with an insertion hole through which the convex portion can be inserted, and an annular projection that surrounds the insertion hole and has a smaller diameter than the inner diameter of the cylindrical portion and protrudes toward the direction in which the contact portion is seated on the valve seat, the protruding length of the annular projection is defined such that the insertion length of the contact portion into the cylindrical portion when the contact portion is seated on the valve seat is shorter than the insertion length of the convex portion into the cylindrical portion.

[0012] The diaphragm valve body according to claim 2 is the diaphragm valve body according to claim 1, wherein the mounting portion is provided with a fitting groove at the base end of the convex portion, into which the opening edge of the insertion hole in the contact portion is fitted, thereby positioning and fixing the contact portion relative to the mounting portion.

[0013] The diaphragm valve according to claim 3 comprises a diaphragm valve body according to claim 1 or 2, and a casing having a cylindrical portion on which the valve seat is provided, and a valve body holding portion that holds the outer edge of the deformed portion of the diaphragm valve body.

[0014] The diaphragm valve body according to claim 1 comprises a contact portion that contacts the valve seat when closed, a deformable portion that is elastically deformed when opened and closed, and a mounting portion formed of a material with higher hardness than the contact portion and the deformable portion, to which the contact portion and the deformable portion are attached. The mounting portion is provided with a convex portion that is inserted into a cylindrical portion, and the contact portion is provided with an insertion hole through which the convex portion can be inserted, and an annular projection that surrounds the insertion hole and has a smaller diameter than the inner diameter of the cylindrical portion and protrudes toward the seating direction of the contact portion to the valve seat. The protrusion length of the annular projection is defined such that the insertion length of the annular projection into the cylindrical portion when the contact portion is seated on the valve seat is shorter than the insertion length of the convex portion into the cylindrical portion. Furthermore, the diaphragm valve according to claim 3 comprises the above-mentioned diaphragm valve body, a cylindrical portion on which a valve seat is provided, and a casing on which a valve body holding portion is formed to hold the outer edge of the deformable portion of the diaphragm valve body.

[0015] Therefore, according to the diaphragm valve body described in claim 1 and the diaphragm valve described in claim 3, when the diaphragm valve body is brought closer to the valve seat during the transition from the open state to the closed state, and the gap between the valve seat and the contact portion gradually narrows, the annular projection is brought closer to the valve seat before the contact portion is seated on the valve seat, and then the annular projection is inserted into the cylindrical portion. As a result, the fluid that has passed through the gap between the valve seat and the contact portion can pass through the small gap between the annular projection and the end of the cylindrical portion (valve seat) for a certain period of time, thus preventing the diaphragm valve from becoming fully closed (the contact portion seated on the valve seat) in an excessively short time. This makes it possible to employ a spring with sufficient biasing force to maintain a good closed state while suitably avoiding the situation in which excessive pressure rise occurs in the upstream space due to the water hammer phenomenon.

[0016] In the diaphragm valve body according to claim 2, a fitting groove is provided at the base end of the convex portion, into which the rim of the insertion hole in the contact portion is fitted, thereby positioning and fixing the contact portion relative to the mounting portion. Therefore, the diaphragm valve body according to claim 2, and the diaphragm valve equipped with such a diaphragm valve body, have a very simple configuration, yet the contact portion can be reliably attached to the mounting portion (convex portion), and moreover, because the rim of the insertion hole has sufficient strength due to the presence of an annular projection formed around the insertion hole, damage such as tearing of the rim of the insertion hole can be suitably avoided during the attachment work of the contact portion to the plate-shaped portion.

[0017] This is an external perspective view of the solenoid valve 1. This is another external perspective view of the solenoid valve 1. This is a cross-sectional view of the solenoid valve 1. This is an external perspective view of the valve body 23. This is an exploded perspective view of the valve body 23. This is a cross-sectional view of the solenoid valve 1 with the main valve 2 in the fully open state. This is a cross-sectional view of the solenoid valve 1 with the main valve 2 in the half-open (half-closed) state. This is a cross-sectional view of the solenoid valve 1 with the main valve 2 in the fully closed state. This is a cross-sectional diagram (conceptual diagram) to explain the gap G that may occur when the main valves 2x and 2 operate. This is a cross-sectional view of the solenoid valve 1A. This is an external perspective view of the valve body 23a. This is an exploded perspective view of the valve body 23a. This is a cross-sectional view of the solenoid valve 1A with the main valve 2a in the fully open state. This is an explanatory diagram to explain the flow of tap water, etc., in the half-open (half-closed) state of the main valve 2a.

[0018] Hereinafter, embodiments of the diaphragm valve body and diaphragm valve according to the present invention will be described with reference to the attached drawings.

[0019] The solenoid valve 1 shown in Figures 1 to 3 is an example of a valve mechanism equipped with a "diaphragm valve," and is configured to be installed in a fluid supply pipe for tap water or other fluids to allow / regulate the passage of fluid. As shown in Figure 3, this solenoid valve 1 has a main valve 2 and a pilot valve 3 formed inside a resin casing 10, and a filter 4 is installed at the inlet Hi of the casing 10.

[0020] Casing 10 is an example of a "casing" and is composed of a casing body 11 and a guide member 12. The casing body 11 is configured to allow fluid to pass from the inlet Hi, to which the upstream piping in the "fluid flow path" is connected, to the outlet Ho, to which the downstream piping is connected. The guide member 12 functions as a mounting member for attaching the actuator 34 of the pilot valve 3 (described later) to the casing body 11, and also functions as a member that guides the valve body 33 (more specifically, the plunger to which the valve body 33 is attached) of the pilot valve 3 in the direction of moving toward and away from the valve seat 32. In this example of the solenoid valve 1, the casing body 11 and the guide member 12 constitute a "valve body holding part" that holds the "diaphragm valve body".

[0021] The main valve 2 is an example of a "diaphragm valve" and, as shown in Figure 3, is configured to include a valve seat (valve port) 22, a valve body 23, and a spring 26. In this main valve 2, the valve body 23 is moved toward and away from the valve seat 22 by the pressure difference between the pressure in the pressure chamber Sp formed in the casing 10 and the pressure in the upstream space Si (space communicating with the inlet Hi) formed in the casing 10.

[0022] The valve seat 22 is an example of a "valve seat provided at the tip of a cylindrical portion that forms a fluid flow path," and is provided at the tip (the end opposite to the outlet Ho) of the cylindrical portion 21 (a cylindrical body that constitutes the downstream space So) in the casing 10. Specifically, in the solenoid valve 1 of this example, a valve port for allowing fluid to flow from the upstream space Si (inlet Hi) to the downstream space So (outlet Ho) is formed at the tip of the cylindrical portion 21 in the casing body 11, and this valve port is configured to function as the valve seat 22 of the main valve 2.

[0023] The valve body 23 is an example of a "diaphragm valve body that restricts the passage of fluid in the closed state and allows the passage of fluid in the open state," and as shown in Figures 4 to 8, it comprises a valve membrane portion 24 and a plate-shaped portion 25. The valve membrane portion 24 is integrally molded with a contact portion 24a, a deformable portion 24b and a fixed portion 24c from a forming material with an elastic modulus lower than that of the forming material of the plate-shaped portion 25 (for example, silicone rubber), and is formed as a circular shallow dish overall.

[0024] In this case, the contact portion 24a is an example of a "contact portion," and as shown in Figure 8, it comes into contact with the valve seat 22 when the main valve 2 is moved to the closed state, thereby closing the valve opening. The deformable portion 24b is also an example of a "deformable portion," and is formed to be thinner than the contact portion 24a and the fixed portion 24c so as to be elastically deformable when transitioning from the open state to the closed state and when transitioning from the closed state to the open state. Furthermore, the fixed portion 24c is an example of an "outer edge portion of a deformable portion," and as shown in Figure 3, it is sandwiched between the casing body 11 and the guide member 12 in the casing 10 and is held by both members 11 and 12 (valve body holding portion).

[0025] In this case, as shown in Figure 5, the contact portion 24a has an insertion hole 24ha (an example of an "insertion hole") through which the convex portion 25a of the plate-shaped portion 25 (described later) can be inserted, and insertion holes 24hb, 24hb through which the convex portions 25b, 25b of the plate-shaped portion 25 (described later) can be inserted. In addition, the contact portion 24a is provided with an annular projection 24p (an example of an "annular projection") that surrounds the insertion hole 24ha, and whose outer diameter is smaller than the inner diameter of the cylindrical portion 21 (slightly smaller: almost the same diameter), and which protrudes in the direction in which the contact portion 24a sits on the valve seat 22 (downward direction in Figures 6 to 8: upward direction in Figure 5).

[0026] In this example, the main valve 2 has an annular projection 24p that is perfectly circular in shape when viewed from the bottom, as shown in Figure 5. Also, in this example, the main valve 2 has a protruding length (height) of the annular projection 24p such that the insertion length of the annular projection 24p into the cylindrical portion 21 when the contact portion 24a is seated on the valve seat 22 is shorter than the insertion length of the convex portion 25a into the cylindrical portion 21. In this case, in the valve body 23 of this example, the annular projection 24p is integrally formed with the contact portion 24a during the molding of the valve membrane portion 24. Therefore, in the valve body 23 of this example, it is possible to achieve the remarkable effects described later without causing a significant increase in manufacturing costs due to the provision of an annular projection 24p on the contact portion 24a.

[0027] The plate-shaped portion 25 is an example of a "mounted portion to which the contact portion and deformable portion are attached," and functions as a "base (valve portion retainer)" that prevents unintended deformation of the valve portion 24 by being integrated with the valve portion 24. It is also formed in a circular shallow dish shape from a material with higher hardness than the valve portion 24 (for example, PPS (Poly Phenylene Sulfide Resin)) so that it functions as a "spring contact portion" to which one end of the spring 26 abuts, as shown in Figure 3.

[0028] In the central part of this plate-shaped portion 25, there is a convex portion 25a (an example of a "convex portion") which is inserted into the cylindrical portion 21 when the valve body 23 is attached to the casing 10, and which straightens the fluid that passes between the contact portion 24a of the valve membrane portion 24 of the main valve 2 and the valve seat 22. In this case, as shown in Figures 5 to 8, in the main valve 2 of this example, an insertion groove portion 25g (an example of an "insertion groove portion") is provided at the base end of the convex portion 25a, which positions and fixes the contact portion 24a (valve membrane portion 24) relative to the plate-shaped portion 25 by fitting the edge of the insertion hole 24ha in the contact portion 24a of the valve membrane portion 24.

[0029] Furthermore, in the main valve 2 of this example, as shown in Figure 5, the convex portions 25b, 25b that hold the valve membrane 24 relative to the plate-shaped portion 25 are provided to protrude in the same direction as the convex portion 25a, in conjunction with the fitting groove portion 25g, when inserted into the insertion holes 24hb, 24hb in the contact portion 24a of the valve membrane 24. In this case, a small hole 25h is opened in one of the two convex portions 25b, 25b to allow fluid to flow from the upstream space Si partitioned within the casing 10 by the valve body 23 into the pressure chamber Sp. In addition, in the central part of the main valve 2 of this example, as shown in Figures 3, 6 to 8, a cylindrical convex portion 25c that functions as a valve seat (valve port) 32 in the pilot valve 3 is provided to protrude in the opposite direction to the plate-shaped portion 25.

[0030] As shown in Figure 3, the spring 26 is housed inside the casing 10 (inside the pressure chamber Sp) such that one end of the coiled portion (the lower end in the figure) is in contact with the valve body 23 (plate-shaped portion 25), and the other end of the coiled portion (the upper end in the figure) is in contact with the guide member 12, thereby enabling the valve body 23 to be biased toward the valve seat 22. In this example, the solenoid valve 1 (main valve 2) has a needle portion 26a that functions as a "cleaning pin" that is continuous with the coiled portion of the spring 26. This needle portion 26a is inserted through a small hole 25h in the plate-shaped portion 25 of the valve body 23, so that the small hole 25h is cleaned by the needle portion 26a as the valve body 23 moves toward and away from the valve seat 22.

[0031] On the other hand, the pilot valve 3, as shown in Figure 3, comprises a valve seat 32, a valve body 33, and an actuator (solenoid) 34. This pilot valve 3 employs a configuration in which the actuator 34 separates the valve body 33 from the valve seat 32, thereby connecting the pressure chamber Sp and the downstream space So. In this case, as described above, the valve seat 32 is provided on a convex portion 25c formed on the plate-shaped portion 25 of the valve body 23 of the main valve 2. The valve body 33 is attached to the tip of the plunger (movable iron core) of the actuator 34 and is moved toward and toward the valve seat 32 by the actuator 34. Furthermore, the actuator 34 moves the plunger toward and toward the hole piece (fixed iron core) by power supplied from a control unit (not shown), thereby moving the valve body 33 toward and toward the valve seat 32. Note that the configuration of the actuator used in this type of "solenoid valve" is well known, so a detailed explanation is omitted.

[0032] When using this solenoid valve 1, the upstream piping (supply source piping: not shown) in the "fluid flow path" is connected to the inlet Hi of the casing 10, and the downstream piping (recipient piping: not shown) is connected to the outlet Ho, and the control unit is connected to the actuator 34. In this state, fluid is supplied via the upstream piping, causing the fluid to flow into the upstream space Si from the inlet Hi, and foreign matter is removed from the fluid as it passes through the filter 4. The fluid that has passed through the filter 4 then flows into the pressure chamber Sp through a small hole 25h provided in one of the convex portions 25b of the plate-shaped portion 25 (the gap between the inner surface of the small hole 25h and the outer surface of the needle portion 26a of the spring 26). As a result, the upstream space Si and the pressure chamber Sp are filled with fluid.

[0033] In this case, in the solenoid valve 1 of this example, as an example, the main valve 2 and the pilot valve 3 are normally in a closed state. Specifically, when no power is supplied to the actuator 34, as shown in Figure 8, the contact portion 24a of the valve body 23 is pressed toward the valve seat 22 by the biasing force of the spring 26 (coil portion), so that the valve opening of the main valve 2 is closed by the valve body 23 (the main valve 2 is in a closed state), and the valve body 33 is pressed toward the convex portion 25c by the biasing force of the spring inside the actuator 34, so that the valve opening of the pilot valve 3 is closed by the valve body 33 (the pilot valve 3 is in a closed state). Note that the spring 26 is not shown in Figures 6 to 8 and Figure 13, which will be referenced later.

[0034] Therefore, as fluid flows from the upstream space Si into the pressure chamber Sp through the small hole 25h, the pressure inside the pressure chamber Sp gradually increases to a pressure similar to that of the upstream space Si (i.e., the pressure inside the upstream piping). In this state, since the pressure inside the pressure chamber Sp is higher than the pressure inside the downstream space So, the contact portion 24a of the valve membrane portion 24 of the valve body 23 remains in contact with (pressed against) the valve seat 22, and the flow of fluid is restricted by the main valve 2.

[0035] On the other hand, when allowing fluid to pass from the upstream piping (upstream space Si) to the downstream piping (downstream space So), the actuator 34 is activated to open the pilot valve 3. Specifically, as shown in Figure 8, the valve body 33, which is in contact with the valve seat 32 and closing the valve port, is moved away from the valve seat 32 by the actuator 34 (moved upward in both figures) as shown in Figure 6, thereby opening the valve port of the pilot valve 3.

[0036] In this case, the fluid in the pressure chamber Sp flows out into the downstream space So, passing through the convex portion 25c as indicated by arrow PO, causing the pressure in the pressure chamber Sp to become lower than the pressure in the upstream space Si. As a result, the pressure in the upstream space Si causes the valve body 23 (contact portion 24a) to move away from the valve seat 22 against the biasing force of the spring 26, and the main valve 2 moves into the open state. Consequently, the upstream space Si and the downstream space So are connected, and the passage of fluid from the upstream space Si to the downstream space So is permitted, as indicated by arrow IO.

[0037] Furthermore, when it is necessary to restrict the passage of fluid again, the actuator 34 is activated to move the pilot valve 3 to the closed state. Specifically, as described above, the actuator 34 moves the valve body 33 toward the valve seat 32 in the opposite direction to when it is moved from the closed state to the open state, thereby closing the valve port of the pilot valve 3 with the valve body 33. At this time, the force with which the actuator 34 presses the valve body 33 toward the valve seat 32 (the convex portion 25c on the plate-shaped portion 25 of the valve body 23), and the force applied to the valve body 23 by the fluid flowing from the upstream space Si into the pressure chamber Sp through the small hole 25h (the gap between the inner surface of the small hole 25h and the outer surface of the needle portion 26a), move the valve body 23 (contact portion 24a) toward the valve seat 22, closing the valve port of the main valve 2. As a result, the main valve 2 is moved to the closed state, restricting the passage of fluid from the upstream space Si to the downstream space So.

[0038] In this case, as mentioned above, if the open main valve 2 is quickly closed, an excessive pressure rise due to the water hammer phenomenon may occur, potentially damaging the solenoid valve (main valve) or causing water leakage in the piping upstream of the solenoid valve. Furthermore, if the biasing force of the valve body 23 by the spring 26 is weakened to avoid such problems, it may become difficult to maintain the main valve 2 in a properly closed state. Therefore, in this example, the solenoid valve 1 (main valve 2) is equipped with a spring 26 that has sufficient biasing force to maintain the main valve 2 in a properly closed state, while an annular projection 24p is provided on the contact portion 24a of the valve diaphragm portion 24 of the valve body 23, thereby employing a configuration that avoids the occurrence of an excessive pressure rise due to the water hammer phenomenon.

[0039] Specifically, as shown in Figure 6, in the main valve 2 which is being moved to the open state, the valve body 23 (contact portion 24a of the valve membrane 24) is sufficiently separated from the valve seat 22. As indicated by the arrow IO in the figure, the fluid in the upstream space Si passes between the valve seat 22 and the contact portion 24a and flows smoothly into the downstream space So. When the main valve 2 is moved from this state to the closed state, the valve body 23 moves closer to the valve seat 22, gradually narrowing the gap between the valve seat 22 and the contact portion 24a, and gradually decreasing the flow rate of the fluid passing through the main valve 2.

[0040] In this case, in the solenoid valve 1 (main valve 2) of this example, as shown in Figure 7, prior to the contact portion 24a being seated on the valve seat 22, the annular projection 24p provided on the contact portion 24a is brought closer to the valve seat 22, and then inserted into the cylindrical portion 21. As mentioned above, this annular projection 24p is formed to be slightly smaller in diameter than the inner diameter of the cylindrical portion 21, so until the contact portion 24a is seated on the valve seat 22, the fluid is allowed to pass through the very small gap created between this annular projection 24p and the end of the cylindrical portion 21 (i.e., the valve seat 22).

[0041] Here, between the contact portion 24a of the valve body 23 and the valve seat 22, a biasing force such as that of the spring 26 acts to cause the contact portion 24a to seat (contact) with the valve seat 22, whereas there is no external force acting in a direction that presses the outer surface of the annular projection 24p against the inner surface of the cylindrical portion 21. Therefore, before the contact portion 24a is seated with the valve seat 22 and the passage of fluid is completely restricted (the main valve 2 is moved to a completely closed state), a state is created in which a small amount of fluid can pass between the valve body 23 and the cylindrical portion 21 for a certain period of time, suppressing the fluid flow velocity. As a result, the main valve 2 is moved to a closed state too quickly, and a situation in which an excessive pressure rise in the upstream space Si due to the water hammer phenomenon is avoided.

[0042] Subsequently, as described above, when the pressure in the pressure chamber Sp is sufficiently increased, the contact portion 24a of the valve body 23 is seated (contacted) with the valve seat 22, as shown in Figure 8, causing the main valve 2 to transition to a completely closed state, and restricting the passage of fluid. In this state, the biasing force of the spring 26 and the spring in the actuator 34, as well as the pressure in the pressure chamber Sp, press the valve body 23 (contact portion 24a) against the valve seat 22 with sufficient force, making it possible to maintain the main valve 2 in a properly closed state.

[0043] Here, the applicant attempted to create a configuration in which, instead of an annular projection 24p formed on the contact portion 24a of the valve body 23, the portion corresponding to the convex portion 25a of the plate-shaped portion 25 (the portion inserted into the insertion hole 24ha of the valve membrane portion 24) is made larger in diameter than the convex portion 25a of the valve body 23, but slightly smaller in diameter than the cylindrical portion 21 on which the valve seat 22 is provided, thereby imposing a restriction similar to that imposed by the annular projection 24p in the main valve 2 when transitioning to the closed state. Specifically, in the main valve 2x shown in the upper figure of Figure 9 (the "main valve" of the configuration attempted by the applicant), there is no "annular projection" on the contact portion 24ax, and the outer diameter L1x of the convex portion 25ax of the plate-shaped portion 25x of the valve body 23x is made larger in diameter so that it is slightly smaller in diameter than the inner diameter L0 of the cylindrical portion 21.

[0044] In this valve body 23x, the outer diameter L1 of the convex portion 25ax is the same as the outer diameter L1 of the annular protrusion 24p provided on the contact portion 24a of the valve body 23 of the main valve 2 shown in the following figure. Therefore, in this main valve 2x, similar to the main valve 2 in which the annular protrusion 24p is provided on the contact portion 24a, when shifting from the open state to the closed state, prior to the contact portion 24ax being seated against the valve seat 22, the portion of the outer diameter L1x of the convex portion 25ax of the plate-like portion 25x is brought closer to the valve seat 22, and then it becomes a state of being inserted into the cylindrical portion 21. For this reason, until the contact portion 24ax is seated against the valve seat 22, the fluid is allowed to pass through an extremely small gap generated between the portion of the outer diameter L1x of the convex portion 25ax and the end portion of the cylindrical portion 21 (that is, the valve seat 22). As a result, similar to the main valve 2 described above, a state occurs in which a small amount of fluid can pass through the main valve 2x over a certain period of time, and it has been found that the occurrence of an excessive pressure increase in the upstream space Si due to the water hammer phenomenon is avoided.

[0045] However, in the valve body 23x provided with the convex portion 25ax having a larger diameter, since it is necessary to increase the diameter of the insertion hole 24hax through which the convex portion 25ax is inserted, it is necessary to make the width L2x in the radial direction of the contact portion 24ax narrower than the width L2 in the radial direction of the contact portion 24a of the valve body 23 of the main valve 2. For this reason, as a result of the angle θx generated in the valve body 23ax when the valve body 23x is separated from the valve seat 22 by a distance L3 being larger than the angle θ generated in the valve body 23a when the valve body 23 is separated from the valve seat 22 by a distance L3, there is a possibility that the gap Gx generated between the edge portion of the convex portion 25ax and the insertion hole 24hax becomes larger than the gap G generated between the edge portion of the convex portion 25a and the insertion hole 24h. In FIG. 9, in order to facilitate the understanding of the gaps G and Gx associated with the deformation of the contact portions 24a and 24ax, the deformation amounts (angles θ and θx) of the contact portions 24a and 24ax are exaggerated and shown as being greatly deformed.

[0046] Therefore, in a main valve 2x that avoids transitioning to a closed state in a short time by increasing the diameter of the convex portion 25ax instead of the annular projection 24p formed on the contact portion 24a, even if it is possible to avoid the occurrence of an excessive pressure rise in the upstream space Si due to the water hammer phenomenon, leakage of water through the gap Gx from the pressure chamber Sp to the downstream space So may cause an unintended pressure drop in the pressure chamber Sp, making it difficult to smoothly transition to a closed state. For this reason, it is preferable to provide an annular projection 24p on the contact portion 24a that allows a small amount of fluid to pass through before it becomes completely closed, without increasing the diameter of the "convex portion" (narrowing the width of the "contact portion").

[0047] Furthermore, although not shown in the diagram, if the configuration of the valve body 23 in this example is modified to increase the protruding length of the annular projection 24p (when the "annular projection" is made to protrude excessively large), when the valve body 23 (contact portion 24a) is separated from the valve seat 22 and the main valve 2 is moved to the open state, the tip of the annular projection 24p with an extended protruding length cannot be sufficiently separated from the cylindrical portion 21, and the flow of fluid passing through the main valve 2 in the open state will be obstructed by the extended annular projection 24p. Therefore, the protruding length of an "annular projection" such as the annular projection 24p must be shorter than the protruding length of the convex portion 25a (convex portion) which has the function of straightening the fluid that has passed through the main valve 2 inside the cylindrical portion 21. Specifically, it must be shorter than the distance between the valve seat 22 and the contact portion 24a in the fully open state of the main valve 2.

[0048] Thus, in this valve body 23, there are provided a contact portion 24a that is brought into contact with the valve seat 22 in the closed state, a deformation portion 24b that is elastically deformed during opening and closing, and a plate-like portion 25 formed of a material having a higher hardness than the contact portion 24a and the deformation portion 24b, to which the contact portion 24a and the deformation portion 24b are attached. The plate-like portion 25 is provided with a convex portion 25a to be inserted into the cylindrical portion 21. The contact portion 24a is provided with an insertion hole 24ha through which the convex portion 25a can pass, and an annular projection 24p that is smaller in diameter than the inner diameter of the cylindrical portion 21 and protrudes in the seating direction of the contact portion 24a with respect to the valve seat 22 so as to surround the insertion hole 24ha. The protruding length of the annular projection 24p is defined such that the insertion length of the annular projection 24p with respect to the cylindrical portion 21 in the state where the contact portion 24a is seated on the valve seat 22 is shorter than the insertion length of the convex portion 25a with respect to the cylindrical portion 21. Further, in this main valve 2, there are provided the above-described valve body 23, the cylindrical portion 21 provided with the valve seat 22, and a casing 10 in which a casing body 11 and a guide member 12 that hold the outer edge portion of the deformation portion 24b in the valve body 23 are formed.

[0049] Therefore, according to this valve body 23 and the main valve 2, when the valve body 23 is brought closer to the valve seat 22 toward the valve seat 22 during the transition from the open state to the closed state and the gap between the valve seat 22 and the contact portion 24a gradually becomes narrower, prior to the contact portion 24a being seated on the valve seat 22, the annular projection 24p is brought closer to the valve seat 22, and then the annular projection 24p is inserted into the cylindrical portion 21. Thus, a state in which the fluid that has passed through the gap between the valve seat 22 and the contact portion 24a is made to pass through a small gap between the annular projection 24p and the end portion (valve seat 22) of the cylindrical portion 21 can be generated for a certain period of time, and it is possible to avoid the main valve 2 from becoming fully closed (the state where the contact portion 24a is seated on the valve seat 22) excessively in a short time. As a result, while adopting a spring 26 having a sufficient biasing force to maintain a good closed state, it is possible to suitably avoid a situation in which an excessive pressure increase occurs in the upstream space Si due to the water hammer phenomenon.

[0050] Furthermore, in this valve body 23, a fitting groove 25g is provided at the base end of the convex portion 25a, which positions and fixes the contact portion 24a relative to the plate-shaped portion 25 by fitting the edge of the insertion hole 24ha in the contact portion 24a. Therefore, with this valve body 23 and main valve 2, despite the very simple configuration, the contact portion 24a (valve membrane portion 24) can be reliably attached to the plate-shaped portion 25 (convex portion 25a), and moreover, because the edge of the insertion hole 24ha has sufficient strength due to the presence of the annular projection 24p formed around the insertion hole 24ha, damage such as tearing of the edge of the insertion hole 24ha can be suitably avoided during the attachment work of the contact portion 24a to the plate-shaped portion 25.

[0051] The configuration of the "diaphragm valve body" and the "diaphragm valve" are not limited to the above-described configuration of the valve body 23 or the configuration of the main valve 2 equipped with the valve body 23.

[0052] For example, in the main valve 2 of the solenoid valve 1 described above, the valve body 23 has an annular projection 24p, which is circular in shape when viewed from the bottom, formed on the contact portion 24a as an example of an "annular projection". However, instead of this valve body 23, the valve body 23a of the main valve 2a of the solenoid valve 1A shown in Figure 10 (another example of a "diaphragm valve") can also be used. In this case, the valve body 23a is an other example of a "diaphragm valve body", and instead of the valve membrane portion 24 with an annular projection 24p provided on the contact portion 24a, it is configured with a valve membrane portion 24A, as shown in Figures 11 and 12, in which a plurality of annularly arranged projections 24pa, 24pa... (another example of an "annular projection") are provided on the contact portion 24aa (another example of a "contact portion"). Note that in Figures 10 to 12, and Figures 13 and 14 which will be referenced later, components that have the same function as the components of the solenoid valve 1 (main valve 2) described above are denoted by the same reference numerals and redundant explanations are omitted. Furthermore, in the solenoid valve 1A of this example, the valve body 23a is provided with 12 protrusions 24pa as an example, but the number of "protrusions" arranged in a ring is not limited to this.

[0053] In this solenoid valve 1A, as shown in Figure 13, when the pilot valve 3 is moved to the open state and the pressure in the pressure chamber Sp becomes lower than the pressure in the upstream space Si, the pressure in the upstream space Si causes the valve body 23a (contact portion 24aa) to move away from the valve seat 22 against the biasing force of the spring 26, causing the main valve 2a to move to the open state, connecting the upstream space Si and the downstream space So, and allowing fluid to pass from the upstream space Si to the downstream space So, as indicated by arrow IO. When the main valve 2a is moved to the closed state from this state, the valve body 23a moves closer to the valve seat 22, gradually narrowing the gap between the valve seat 22 and the contact portion 24aa, and gradually decreasing the flow rate of fluid passing through the main valve 2a.

[0054] In this case, as shown in Figure 14, the valve body 23a is provided with multiple protrusions 24pa, 24pa... arranged in a ring shape to form an "annular protrusion". Therefore, when the main valve 2A equipped with this valve body 23a is moved to the closed state, fluid is passed between the valve seat 22 and the contact portion 24aa as described above, and also between the adjacent protrusions 24pa, 24pa. Consequently, the flow rate of fluid passing from the upstream space Si to the downstream space So from the moment the transition of the main valve 2A to the closed state begins until the contact portion 24aa of the valve body 23a seats on the valve seat 22 and the main valve 2A becomes fully closed is slightly greater than the flow rate when the main valve 2 is moved to the closed state. Therefore, the solenoid valve 1A equipped with this valve body 23A can more effectively avoid the occurrence of excessive pressure rise in the upstream space Si due to the water hammer phenomenon. This makes it possible to achieve the same effects as the valve body 23 and the main valve 2 equipped with the valve body 23 described above.

[0055] Furthermore, although the explanation described an example of a valve body 23 (23a) having a valve membrane portion 24 in which a contact portion 24a (24aa), a deformable portion 24b, and a fixed portion 24c are integrally formed, the "contact portion" and "deformable portion" can also be attached separately to the "mounted portion" as a solid structure to constitute a "diaphragm valve body" (not shown). In addition, although the explanation described an example of a configuration that includes a spring 26 for biasing the valve body 23 (diaphragm valve body) and a needle portion 26a that functions as a cleaning pin, a configuration without a spring or cleaning pin can also be adopted (not shown).

[0056] According to the diaphragm valve body of the present invention, by providing an annular projection, which is inserted into a cylindrical portion with a valve seat at its tip in the closed state, at a contact portion that comes into contact with the valve seat in the closed state, it is possible to avoid the diaphragm valve becoming fully closed in an excessively short time. As a result, it is possible to suitably avoid situations in which excessive pressure rise occurs in the upstream space of the diaphragm valve due to the water hammer phenomenon, and therefore it can be widely applied to various diaphragm valves that restrict / allow the passage of fluid.

[0057] 1, 1A Solenoid valve 2, 2a Main valve 3 Pilot valve 4 Filter 10 Casing 11 Casing body 12 Guide member 21 Cylindrical part 22, 32 Valve seat 23, 23a, 33 Valve body 24, 24A Valve membrane part 24a, 24aa Contact part 24b Deformable part 24c Fixed part 24p Annular projection 24pa Projection 24ha, 24hax Through hole 24hb Through hole 25 Plate-shaped part 25a-25c Convex part 25g Insertion groove part 25h Small hole 26 Spring 26a Needle part 34 Actuator G Gap Hi Inlet Ho Outlet Si Upstream space So Downstream space Sp Pressure chamber

Claims

1. A diaphragm valve body that restricts the passage of fluid in a closed state when seated on a valve seat provided at the tip of a cylindrical portion forming a fluid passage, and allows the passage of fluid in an open state when separated from the valve seat, comprising: a contact portion that contacts the valve seat in the closed state; a deformable portion that is elastically deformed when transitioning from the open state to the closed state and when transitioning from the closed state to the open state; and a mounting portion formed of a material with higher hardness than the contact portion and the deformable portion, to which the contact portion and the deformable portion are attached, wherein the mounting portion is provided with a convex portion that is inserted into the cylindrical portion, and the contact portion is provided with an insertion hole through which the convex portion can be inserted, and an annular projection that surrounds the insertion hole and has a diameter smaller than the inner diameter of the cylindrical portion and protrudes toward the seating direction of the contact portion toward the valve seat, The annular projection has a protruding length such that, when the contact portion is seated on the valve seat, the insertion length of the cylindrical portion into the cylindrical portion is shorter than the insertion length of the convex portion into the cylindrical portion.

2. The diaphragm valve body according to claim 1, wherein the mounting portion is provided with a fitting groove at the base end of the convex portion into which the opening edge of the insertion hole in the contact portion is fitted, thereby positioning and fixing the contact portion relative to the mounting portion.

3. A diaphragm valve comprising a diaphragm valve body according to claim 1 or 2, and a casing having a cylindrical portion on which the valve seat is provided, and a valve body holding portion that holds the outer edge of the deformed portion of the diaphragm valve body.

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