Valve and vacuum pump

Abstract

To provide a valve having a backward flow prevention function for reducing a risk of adhesion of a valve element at the time of its use.SOLUTION: A valve 1 having a backward flow prevention function comprises: a backward flow prevention downstream side frame body 3A in which a valve seat port 33 surrounded by a valve seat 32 is formed while demarcating a valve chamber 31 communicating with a flow path in an upstream side via the valve seat port 33; a valve element 5 disposed in the valve chamber 31 so as to be capable of traveling between a state in which it is in contact with the valve seat 32 and a state in which it separates from the valve seat 32; an adhesion-release member 7 that is disposed such that the end can abut on the valve element 5 through the wall of the backward flow prevention downstream side frame body 3A and can push the valve element 5 in a direction separated from the valve seat 32 by receiving applied force from the outside of the backward flow prevention downstream side frame body 3A; and a use operation interlocking member 92 that is linked to operation when an operator sets a valve 1 to a usage state, is disposed so as to be capable of abutting on the adhesion-release member 7, and has a form capable of temporarily reinforcing applied force to the adhesion-release member 7 in an operator's operation process.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a valve and a vacuum pump, and more particularly to a valve having a backflow prevention function and characterized by a structure for preventing the valve body from sticking, and a vacuum pump equipped with such a valve. [Background technology]

[0002] In fluidic devices such as vacuum pumps, valves (also called check valves, non-return valves, or check valves) with a backflow prevention function that allows fluid to flow in only one direction are used. Such valves with a backflow prevention function have a valve element disposed in a flow path formed inside the valve, and an opening (referred to as a "valve seat opening" in this specification) is formed in the flow path that is not blocked by the valve element in the case of a forward flow, but is blocked by the valve element in the case of a reverse flow.

[0003] In valves with such backflow prevention functions, moisture, sludge, etc. can cause the valve disc to stick to the valve seat around the valve seat opening, which can prevent the valve disc from opening due to the pressure difference between the upstream and downstream sides (also called "cracking pressure"), which would otherwise allow the valve disc to open as designed (no longer blocking the valve seat opening). Valves equipped with means to prevent this type of valve disc sticking have also been proposed (see, for example, Patent Documents 1 and 2).

[0004] The check valve disclosed in Patent Document 1 has a pocket portion (50) formed therein for collecting solid components of the slurry that have settled at a position lower than an opening (38) serving as a valve seat that is closed by a ball (26) serving as a valve element. This prevents the solid components of the slurry from accumulating around the ball and causing the ball (26) to stick.

[0005] The valve (pressure-maintaining valve with check valve 20) disclosed in Patent Document 2 includes a valve seat (32) where a valve disc (valve 30) closes a seal surface (23c) that surrounds the flow path, a cylindrical valve stem (34) extending perpendicular to the seal surface (23c), and a hollow cylindrical resin pad (36) made of a self-lubricating resin that is attached to the outer periphery of the valve disc and whose outer periphery slides against the inner surface of the valve guide hole (24a). The self-lubricating resin reduces sliding friction with the valve guide hole (24a), significantly preventing sticking between the valve disc (valve 30) and the valve guide hole (24a). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-046409 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-044787 Summary of the Invention [Problem to be solved by the invention]

[0007] The valve disc sticking prevention structure disclosed in Patent Document 1 can only be applied to valves that allow fluid to flow from a higher position to a lower position than the valve disc, and the valves that can be used are limited. Furthermore, the valve disc sticking prevention structure disclosed in Patent Document 2 cannot prevent the valve disc from sticking to the valve seat. In any case, in valves with backflow prevention functions, particularly those used in vacuum pumps, the differential pressure between atmospheric pressure and the pressure inside the pump is small, and even slight sticking can prevent the valve disc from opening. Therefore, to prevent the valve disc from sticking, an effective method is to use a pin or the like to forcibly push the valve disc away from the valve seat.

[0008] However, in the past, the work of forcibly pushing the valve disc away from the valve seat using a pin or the like was performed independently of operations to put the valve into use, such as maintenance and inspection. Therefore, even if the work was forgotten or the work was performed, there was a risk that the valve disc would become stuck when it was time to use it, due to the passage of time.

[0009] The present invention has been made in view of the above points, and aims to provide a valve with a backflow prevention function that reduces the risk of the valve disc becoming stuck when in use, and also to provide a vacuum pump equipped with such a valve that is less likely to suffer from malfunctions due to valve malfunctions. [Means for solving the problem]

[0010] In order to solve the above problems, the valve according to the present invention comprises: A valve having a backflow prevention function in which a flow path through which a fluid flows is formed inside, a backflow prevention downstream frame having a frame shape with a valve seat opening at an end where the flow path diameter is reduced and surrounded by a valve seat, the frame defining, by an inner wall surface, a valve chamber which is an internal space communicating with an upstream flow path via the valve seat opening; a valve element disposed in the valve chamber so as to be movable between a state in contact with the valve seat and a state separated from the valve seat, the valve element having a shape that closes the valve seat port when in contact with the valve seat; a release body that penetrates the wall of the backflow prevention downstream frame so that its tip can come into contact with the valve body, and that can push the valve body in a direction away from the valve seat when a force is applied from outside the backflow prevention downstream frame; a use operation interlocking member that is a member that is interlocked with at least the operation of an operator when putting the valve into a use state, that is arranged so as to be able to come into contact with the fixation release body, and that has a form that can temporarily increase the force applied to the fixation release body during the operation process by the operator; The present invention is characterized by the following.

[0011] This valve preferably further comprises a valve body biasing member disposed within the valve chamber and constantly biasing the valve body toward the valve seat.

[0012] The valve further comprises a backflow prevention upstream frame which is located upstream of the backflow prevention downstream frame and has a frame shape with an inlet port formed through its peripheral wall for introducing a fluid, and which defines, by its inner wall surface, an upstream chamber which is an internal space communicating with the valve chest via the valve seat port, the release body has a pin shape, one end of which passes through the valve seat opening so as to be able to protrude from the valve seat opening into the valve chamber, and the other end of which is exposed when viewed from outside the upstream chamber so as to face the operation interlocking member, and is movably disposed within the backflow prevention upstream frame; Preferably, a portion of the upstream chamber forms a part of a flow path for fluid to flow from the inlet port to the valve seat port.

[0013] Preferably, the valve further comprises a release body biasing member disposed in the upstream chamber and constantly biasing the release body toward the use operation interlocking member.

[0014] In this valve, the valve chamber and the upstream chamber are each defined coaxially by an inner wall surface having a rotationally symmetrical shape, the center of which is an imaginary axis extending in a straight line, The valve disc has a rotationally symmetrical shape, and when it is in contact with the valve seat, the center of gravity is located on the axis. It is preferable that at least the portion of the release body located within the upstream chamber has a rotationally symmetrical shape, the center of gravity is located on the axis or at a position slightly off the axis, and the center of gravity is movable along the axis.

[0015] In this valve, it is also preferable that the tip portion on one end of the fixation release body has a rotationally asymmetric shape, and the position of the most distal end is off the axis.

[0016] The valve further comprises a piston frame having a frame shape in which a connection part is formed for connecting an introduction pipe for introducing a fluid from the outside, and defining by an inner wall surface a piston chamber which is an internal space communicating with the introduction pipe connected to the connection part via a through-hole which is an inlet port, the backflow prevention downstream frame and the backflow prevention upstream frame are integrated and configured as a piston that is movably disposed in the piston chamber, The piston has a shape that allows it to move along the inner wall surface with its outer wall surface in close contact with at least the inner wall surface around the inlet, and is arranged so that as it moves, the inlet switches between a state where it overlaps with the inlet and a state where it does not overlap with the inlet, It is preferable that the retraction port of the piston frame and the introduction port of the piston be switched between an overlapping state and a non-overlapping state, thereby further providing a flow path opening and closing function.

[0017] When the flow path opening and closing function is provided, it is preferable that the flow path opening and closing function further includes a flow rate changing function that can change the flow rate of the flowing fluid depending on the degree of overlap between the inlet of the piston frame and the inlet of the piston.

[0018] Preferably, the valve further comprises a piston biasing member disposed in the piston chamber and constantly biasing the piston toward the use operation interlocking member.

[0019] In this valve, it is preferable that the central axes of the sticking release body, the valve body, and the piston are coaxial.

[0020] Furthermore, in this valve, it is preferable that the operation interlocking member has a rotating cam shape on which is formed at least a non-stick release operating surface that contacts the stick release body when the valve body is not pushed in or does not contact the stick release body, and a stick release operating surface that contacts the stick release body when the valve body is pushed in, and that as the operation is performed, the member rotates so that the surface that contacts the stick release body switches in turn between the stick release non-operating surface, the stick release operating surface, and the stick release non-operating surface.

[0021] In addition, in this valve, it is preferable that the operation interlocking member has a rotating cam shape formed with a closed state contact surface that contacts the piston when the inlet is not overlapping the retraction port of the piston frame, an open state contact surface that contacts the anti-sticking body when the valve body is not pushed in or that does not contact the anti-sticking body and contacts the piston when the inlet overlaps the retraction port of the piston frame, and a anti-sticking operating surface that contacts the anti-sticking body when it is pushing the valve body between the closed state contact surface and the open state contact surface, and that rotates when operated so that the surface that contacts the piston can be switched between the closed state contact surface and the open state contact surface.

[0022] In addition, in this valve, it is preferable that the operation interlocking member has a rotating cam shape formed with a closed state contact surface that comes into contact with the piston when the introduction port is not overlapping with the retraction port of the piston frame, a maximum open state contact surface that comes into contact with the anti-sticking body when the valve body is not pushed in or does not come into contact with the anti-sticking body and comes into contact with the piston when the introduction port is overlapping with the retraction port of the piston frame to the maximum extent, an intermediate open state contact surface that comes into contact with the anti-sticking body when the valve body is not pushed in or does not come into contact with the anti-sticking body and comes into contact with the piston when the introduction port is overlapping with the retraction port of the piston frame to a smaller extent than the maximum, and an anti-sticking operating surface that comes into contact with the anti-sticking body when the valve body is pushed in between adjacent contact surfaces among the closed state contact surface, the maximum open state contact surface and the intermediate open state contact surface, and that the operation interlocking member rotates when operated so that the surface that comes into contact with the piston can be switched between the closed state contact surface, the maximum open state contact surface and the maximum open state contact surface.

[0023] A vacuum pump according to the present invention is characterized in that it is equipped with the above-described valve as at least one valve for controlling the flow of fluid flowing inside.

[0024] In this vacuum pump, at least one valve is preferably a gas ballast valve. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a valve with a backflow prevention function that reduces the risk of the valve disc becoming stuck when it is actually used, and by incorporating such a valve, it is possible to provide a vacuum pump that is less likely to malfunction due to the valve not working. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a cross-sectional view of the valve according to the embodiment when it is in a closed state. [Figure 2] FIG. 2 is a cross-sectional view of the valve according to the embodiment when it is in a partially open state. [Figure 3] FIG. 2 is a cross-sectional view of the valve according to the embodiment when it is in a maximum open state. [Figure 4] FIG. 2 is an enlarged view of an operating member of the valve according to the embodiment. [Figure 5] 10A and 10B are explanatory diagrams of a backflow prevention function of a valve according to an embodiment. [Figure 6] 3A and 3B are explanatory diagrams of a flow path opening / closing function and a flow rate changing function of a valve according to an embodiment. [Figure 7] 5A and 5B are explanatory diagrams illustrating a valve body sticking release function of the valve according to the embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing a modified example of the fixing release body. DETAILED DESCRIPTION OF THE INVENTION

[0027] (Valve 1 configuration) FIG. 1 is a cross-sectional view of a valve 1 according to an embodiment in a closed state, FIG. 2 is a cross-sectional view of the valve 1 in a middle open state, and FIG. 3 is a cross-sectional view of the valve 1 in a maximum open state. FIG. 4 is an enlarged view of an operating member 9 of the valve 1. Valve 1 to which the present invention is applied will be described with reference to these figures. Note that while FIGS. 2 and 3 show a state in which the valve element 5 is closed (see FIG. 5(b)), the valve element 5 opens when fluid F flows (see FIG. 5(a)). Also, the figures do not necessarily strictly show all of the specific shapes and specific configurations.

[0028] As shown in FIGS. 1 to 3, valve 1 has an internal flow path formed therein and is used to control the flow of fluid F. Valve 1 has a flow path opening / closing function that switches between a closed state (the state in FIG. 1 ) that blocks the flow of fluid F between the flow paths and an open state (the states in FIGS. 2 and 3 ) that allows fluid F to flow between the flow paths. Valve 1 also has a flow rate changing function that switches between an open state (the state in FIG. 3 ) that allows fluid F to flow between the flow paths at a maximum flow rate and an intermediate open state (the state in FIG. 2 ) that allows fluid F to flow at a rate lower than the maximum flow rate. Valve 1 also has a backflow prevention function that allows fluid F to flow only in one direction (forward flow) between the flow paths (see FIG. 5 ). Conventionally, valves with flow path opening / closing and flow rate changing functions and valves with backflow prevention functions are separate entities. However, valve 1 is configured as a compact valve that has these functions integrated into one. Valve 1 also has a valve element 5 disposed therein to perform the backflow prevention function, and a valve element sticking release function to prevent malfunctions caused by sticking of valve element 5. Before describing these various functions in detail, we will first explain the configuration of valve 1. Valve 1 changes shape between the open state, intermediate open state, and fully open state, but below, when explaining specific shapes, valve 1 in the closed state as shown in Figure 1 may be referred to as valve 1A, valve 1 in the intermediate open state as shown in Figure 2 as valve 1B, and valve 1 in the fully open state as shown in Figure 3 as valve 1C.

[0029] Valve 1 having these functions is often used by being incorporated between flow paths of fluidic devices such as vacuum pumps. Valve 1 has connection parts on both ends of a flow path formed inside, with an upstream pipe of fluidic device 100 (referred to herein as "inlet pipe 101") connected to the upstream connection part, and a downstream pipe of fluidic device 100 (referred to herein as "outlet pipe 102") connected to the downstream connection part, and controls the flow direction and flow rate of fluid F between inlet pipe 101 and outlet pipe 102 in fluidic device 100.

[0030] The valve 1 is generally formed in a generally cylindrical shape centered on an imaginary axis L (hereinafter simply referred to as "axis L") extending in a straight line from the first direction side L1 to the second direction side L2, and is equipped with a piston frame 2 that serves as a housing surrounding the flow path, a piston 3 that is capable of reciprocating within the piston frame 2, a piston biasing member 4 for biasing the piston 3, a valve element 5 that is arranged in the flow path of the piston 3 and is capable of reciprocating, a valve element biasing member 6 for biasing the valve element 5, a sticking release body 7 that is capable of reciprocating to move the valve element 5, a sticking release body biasing member 8 for biasing the sticking release body 7, an operating member 9 that is operated by an operator during use, and a cover 10 that serves as a housing surrounding the operating member 9. In addition, the valve 1 is appropriately equipped with a sealing member S such as an O-ring or packing to prevent leakage of the fluid F flowing inside.

[0031] The piston frame 2 is made of a hard material appropriately selected from metal, resin, glass, ceramic, etc., and has a generally cylindrical frame shape with a large opening on the first direction side L1 and a bottom on the second direction side L2, centered on the axis L. Due to this frame shape, the piston frame 2 defines a piston chamber 21, which is an internal space surrounded by an inner wall surface. The piston frame 2 is formed, on the side of the first direction side L1 of the outer wall surface, with an upstream connection portion 22, which is a recess for connecting an introduction pipe 101 for introducing a fluid from the outside (the introduction pipe 101 of the fluid device 100 to be incorporated), and an inlet 23, which is a through hole communicating with the piston chamber 21 and the introduction pipe 101 connected to the upstream connection portion 22. Furthermore, the piston frame 2 is formed at its end on the second direction side L2 with a downstream connection portion 24, which is a protrusion for connecting a discharge pipe 102 for discharging fluid from the outside (the discharge pipe 102 of the fluid device 100 to be incorporated), and an outlet port 25, which is a through-hole that communicates between the piston chamber 21 and the discharge pipe 102 connected to the downstream connection portion 24. Although not particularly limited, the piston frame 2 of the embodiment has a slightly larger diameter on the bottom side (second direction side L2) of the piston chamber 21 for the purposes of improving the fitting accuracy with the piston 3 described below and forming a retaining mechanism for the piston 3, and has a connected structure of a first piston frame 2A and a second piston frame 2B that are processed separately.

[0032] The piston 3 is made of a hard material appropriately selected from metal, resin, glass, ceramic, etc., and has an overall, approximately cylindrical frame shape centered on the axis L. The interior of the piston 3 forms part of the flow path of the valve 1, and has a structure in which a backflow prevention downstream frame 3A on the second direction side L2 and a backflow prevention upstream frame 3B on the first direction side L1 are integrated, with the boundary being the area that stops backflow when the backflow prevention function is exerted. The piston 3 is fitted into a piston chamber 21A within the first piston frame 2A via a seal member S1(S) so as to be slidable along the inner surface of the first piston frame 2A of the piston frame 2. The piston 3 is shaped to be able to reciprocate along the inner wall surface of the piston chamber 21 with its outer wall surface in close contact with the inner wall surface around the retraction port 23 of the piston frame 2. Furthermore, the piston 3 is fitted into the first direction side L1 of the piston chamber 21 of the piston frame 2 via a sealing member S1, so that the fluid F flowing inside the piston chamber 21 does not leak from between the piston frame 2 and the piston 3 to the first direction side L1.

[0033] The backflow prevention downstream frame 3A has a frame shape whose inner wall surface is rotationally symmetrical about the axis L. Due to this frame shape, the backflow prevention downstream frame 3A defines an internal space enclosed by the inner wall surface, a valve chamber 31 that forms part of the flow path of the valve 1. The flow path diameter of the backflow prevention downstream frame 3A is narrowed to a cone shape at its end, and the cone-shaped surface forms a valve seat 32 that receives the valve disc 5, which will be described later. The area of ​​the backflow prevention downstream frame 3A surrounded by the valve seat 32 is formed with a valve seat opening 33, which is a through-hole. The backflow prevention downstream frame 3A also has a valve chamber cover 34, which is located at the end of the second direction side L2 to cover the valve chamber 31 and prevent the valve disc 5 and valve disc biasing member 6, which will be described later, from moving out of the valve chamber 31 to the second direction side L2 after they are placed inside the valve chamber 31. The valve chamber cover 34 has an opening (through-hole) in its center that allows the fluid F to flow. As a result, the valve chamber 31 communicates with the upstream flow path through the valve seat port 33 and also communicates with the downstream flow path through the opening in the valve chamber lid 34 .

[0034] The backflow prevention upstream frame 3B is located upstream of the backflow prevention downstream frame 3A and has a frame shape whose inner wall surface is rotationally symmetrical about the axis L. This frame shape defines an internal space enclosed by the inner wall of the backflow prevention upstream frame 3B, an upstream chamber 35 that partially constitutes part of the flow path of the valve 1. The upstream chamber 35 is composed of a first upstream chamber 35a defined at the end of the first direction side L1, and a second upstream chamber 35b defined at the second direction side L2 of the first upstream chamber 35a. The second upstream chamber 35b has a smaller diameter than the first upstream chamber 35a but is equivalent to the valve seat opening 33 of the backflow prevention downstream frame 3A. The upstream chamber 35 is coaxial with the valve chamber 31 of the backflow prevention downstream frame 3A about the axis L and communicates with the valve chamber 31 via the valve seat opening 33. The backflow prevention upstream frame 3B is formed with an inlet 36 that penetrates the peripheral wall of the second upstream chamber 35b to introduce the fluid F. The inlet 36 is positioned so that, as the piston 3 moves, it switches between overlapping with the inlet 23 of the piston frame 2 (the state shown in FIG. 3) and not overlapping with it (the state shown in FIG. 1). In other words, the piston 3 is positioned within the piston chamber 21 so that, as the piston 3 moves, the inlet 36 switches between overlapping with the inlet 23 and not overlapping with it. With this configuration, part of the second upstream chamber 35b of the backflow prevention upstream frame 3B forms part of the flow path of the valve 1 that allows the fluid F to flow from the inlet 36 to the valve seat opening 33. In addition, the backflow prevention upstream frame body 3B has an upstream chamber lid 37 that is placed at the end of the first direction side L1 to cover the upstream chamber 35 so that the later-described fixation release body 7 and later-described fixation release body biasing member 8 do not come out of the upstream chamber 35 to the first direction side L1 after they are placed in the upstream chamber 35, and has an opening (through hole) formed so that the end face of the later-described fixation release body 7 can be exposed.

[0035] The piston biasing member 4 is, for example, a coil spring, and is disposed in the piston chamber 21B in the second piston frame 2B of the piston frame 2. The piston biasing member 4 is disposed with one end abutting against the bottom surface of the piston chamber 21 on the second direction side L2, and the other end abutting against the end surface of the piston 3 on the second direction side L2. As a result, the piston biasing member 4 constantly biases the piston 3 toward the first direction side L1.

[0036] The valve disc 5 is made of a hard material appropriately selected from metal, resin, glass, ceramic, etc., and is disposed facing the valve seat 32 within the valve chamber 31 in the backflow prevention downstream frame 3A of the piston 3. The valve disc 5 is movable between a state in contact with the valve seat 32 and a state away from the valve seat 32. The valve disc 5 has a shape that closes the valve seat opening 33 when in contact with the valve seat 32, and in this embodiment, has a spherical shape. As described above, the piston 3 has a substantially cylindrical shape centered on the axis L, and the valve disc 5 is disposed so that its center of gravity is on the axis L when in contact with the valve seat 32. The valve disc 5 can close the valve seat opening 33 when in contact with the valve seat 32, and can block the flow of fluid F from the valve chamber 31 to the upstream side.

[0037] The valve disc biasing member 6 is, for example, a coil spring, and is disposed within the valve chamber 31 in the backflow prevention downstream frame 3A of the piston 3. The piston biasing member 4 is disposed with one end abutting against the valve chamber lid 34 on the second direction side L2 of the valve chamber 31, and the other end abutting against the surface of the second direction side L2 of the valve disc 5. As a result, the valve disc biasing member 6 constantly biases the valve disc 5 toward the valve seat 32 on the first direction side L1.

[0038] The sticking release body 7 is formed from a material capable of defining a shape appropriately selected from metal, resin, glass, ceramic, elastomer, rubber, or a combination of these. The sticking release body 7 is arranged so that it penetrates the wall of the backflow prevention downstream frame 3A from the outside, with its tip capable of contacting the valve disc 5 arranged inside the backflow prevention downstream frame 3A, and is capable of pressing the valve disc 5 in a direction away from the valve seat 32 when a force is applied from outside the backflow prevention downstream frame 3A. Specifically, the sticking release body 7 has a pin shape that is rotationally symmetrical about the axis L, and is arranged inside the backflow prevention upstream frame 3B so that it can move along the axis L. The central axis of the sticking release body 7 is arranged coaxially with the central axes of the valve disc 5 and the piston 3. More specifically, the sticking release body 7 comprises an exposed pin end portion 71 having an outer diameter corresponding to the diameter of the through-hole in the upstream chamber lid 37 of the backflow prevention upstream frame 3B on the first direction side L1, a pin collar portion 72 connected to the exposed pin end portion 71 and having an outer diameter corresponding to the diameter of the first upstream chamber 35a of the backflow prevention upstream frame 3B, and a narrow pin diameter portion 73 connected to the pin collar portion 72 and having a narrow outer diameter extending toward the second direction side L2 along the second upstream chamber 35b of the backflow prevention upstream frame 3B. The sticking release body 7 penetrates the valve seat opening 33 so that the tip of the narrow pin diameter portion 73 on the second direction side L2 can protrude from the valve seat opening 33 into the valve chamber 31, and the end face of the exposed pin end portion 71 on the first direction side L1 is exposed from the through-hole in the upstream chamber lid 37 when viewed from outside the upstream chamber 35. The length of the sticking release body 7 is specified so that, when the surface on the first direction side L1 of the pin flange portion 72 is in contact with the upstream chamber lid 37 and the tip of the pin small diameter portion 73 is in contact with or slightly separated from the valve disc 5 without pressing the valve disc 5, the surface on the first direction side L1 of the pin exposed end portion 71 is in a position that is roughly the same as or slightly recessed from the surface of the upstream chamber lid 37. As a result, when an external force is applied to the sticking release body 7 so that the surface on the first direction side L1 of the pin exposed end portion 71 is recessed to some extent from the upstream chamber lid 37, the sticking release body 7 moves relatively to the piston 3 toward the second direction side L2, and the tip of the pin small diameter portion 73 presses the valve disc 5.The fixation release body 7 is disposed at a position on the first direction side L1 further than the inlet 23 of the backflow prevention upstream frame 3B, with the gap between the pin small diameter portion 73 and the wall surface of the second upstream chamber 35b filled with the seal member S2 (S). This prevents the fluid F flowing through the second upstream chamber 35b from leaking between the backflow prevention upstream frame 3B and the fixation release body 7 toward the first direction side L1.

[0039] The sticking release body biasing member 8 is, for example, a coil spring, and is disposed within the first upstream chamber 35a of the upstream chamber 35 in the backflow prevention upstream frame 3B of the piston 3. The piston biasing member 4 is disposed with one end abutting against an end face on the second direction side L2 of the first upstream chamber 35a, and the other end abutting against the surface on the second direction side L2 of the pin flange portion 72 of the sticking release body 7. As a result, the sticking release body biasing member 8 constantly biases the sticking release body 7 toward the first direction side L1.

[0040] The operation member 9 includes a use operation input member 91 for an operator to input an operation, and a use operation interlocking member 92 that interlocks with the use operation input member 91 (see also FIG. 4).

[0041] The use operation input member 91 is a long, thin rod-like lever, and the diameter and length of the gripping portion are appropriately set so that the operator can grip the tip and apply a force amplified by this principle at the base end. The use operation input member 91 is always operated when the operator puts the valve into use.

[0042] The usage operation interlocking member 92 has a rotating cam shape, is connected to the base end of the usage operation input member 91, and rotates around a rotation axis 9a extending perpendicular to the axis L in accordance with the inclination of the usage operation input member 91. The usage operation interlocking member 92 has multiple surfaces around it at different distances from the rotation axis 9a, and is positioned by the rotation axis 9a fixed to the piston frame 2 so that, regardless of which surface is facing the second direction side L2, it is in face-to-face contact with the surface of the upstream chamber lid 37 of the piston 3 biased by the piston biasing member 4 and the surface on the first direction side L1 of the pin exposed end 71 of the fixation release body 7 biased by the fixation release body biasing member 8. In addition, the usage operation interlocking member 92 has a configuration that allows it to temporarily increase the force applied to the fixation release body 7 when a specific surface is facing the second direction side L2 during operation by the operator. 4, the usage operation interlocking member 92 is formed in a generally right-angled triangular shape when viewed from the side, and includes a first cam plane 92a that is relatively short from the rotation axis 9a, a second cam plane 92b that is farther from the rotation axis 9a than the first cam plane 92a and forms an angle of approximately 90° with the first cam plane 92a, and a third cam plane 92c that corresponds to the hypotenuse of the right-angled triangle but is not the surface used to come into contact with the piston 3 during use. The usage operation interlocking member 92 also has curved corners between the planes, including a first cam curved surface 92d between the first cam plane 92a and the second cam plane 92b, and a second cam curved surface 92e between the second cam plane 92b and the third cam plane 92c that is farther from the rotation axis 9a than the second cam plane 92b. From the corner between the first cam plane 92a and the third cam plane 92c, an operation input member 91 extends along an imaginary lever axis L3 that extends from the center of the rotation shaft 9a in a direction opposite to the plane facing the second cam plane 92b, and by changing the inclination of the operation input member 91, the plane facing the second direction side L2 can be switched between the first cam plane 92a, the first cam curved surface 92d, the second cam plane 92b, and the second cam curved surface 92e in this order, or the reverse. This switching of the cam surfaces is performed to fulfill the flow path opening / closing function, the flow rate changing function, and the valve disc sticking release function of the valve 1, and will be explained in more detail in the function explanation below.

[0043] The cover 10 is made of a material appropriately selected from metal, resin, etc., and is a cover member that covers the first direction side L1 of the piston frame 2. The cover 10 has an opening, through which the use operation input member 91 protrudes and covers the use operation interlocking member 92 on the inside.

[0044] The valve 1 configured in this manner has a backflow prevention function as the valve element 5 moves due to the pressure difference between the upstream and downstream sides, a flow path opening / closing function and a flow rate changing function as the piston 3 moves with the rotational movement of the operating member 9, and a valve element sticking release function as the sticking release body 7 moves with the rotational movement of the operating member 9. Each of these functions will be described in detail below.

[0045] (Valve 1 backflow prevention function) Figure 5 is an explanatory diagram of the backflow prevention function of valve 1, with Figure 5(a) showing a state in which valve element 5 is open and fluid F is flowing forward inside, and Figure 5(b) showing a state in which the backflow prevention function is working and preventing backflow of fluid F inside. First, the backflow prevention function of valve 1 will be explained using Figure 5.

[0046] The valve 1 disposed between the inlet pipe 101 and the outlet pipe 102 exhibits a backflow prevention function by changing the shape of the inside of the valve chamber 31 of the backflow prevention downstream frame 3A of the piston 3.

[0047] More specifically, when the pressure P1 in the inlet pipe 101 connected to the upstream connecting part 22 is greater than the pressure P2 in the outlet pipe 102 connected to the downstream connecting part 24 of the piston frame 2, and the pressure difference is equal to or greater than a predetermined pressure difference (cracking pressure), a force due to the pressure difference is applied to the valve disc 5 from the first direction side L1 through the valve seat port 33, as shown in Figure 5(a). When the force due to this pressure difference exceeds the force of the valve disc biasing member 6 biasing the valve disc 5, the valve disc 5 moves in a direction away from the valve seat 32, and the fluid F flows between the valve disc 5 and the valve seat 32.

[0048] On the other hand, when the pressure P1 in the inlet pipe 101 is lower than the pressure P2 in the outlet pipe 102, a force due to the pressure difference is applied to the valve disc 5 from the second direction side L2, as shown in Figure 5(b). Furthermore, because the force of the valve disc biasing member 6 biasing the valve disc 5 toward the first direction side L1 is always applied to the valve disc 5, the valve disc 5 moves in a direction contacting the valve seat 32, the valve disc 5 closes the valve seat opening 33, and the flow of the fluid F is blocked. Note that even when the pressure P1 in the inlet pipe 101 is higher than the pressure P2 in the outlet pipe 102, if the pressure difference is equal to or lower than the cracking pressure, the force due to the pressure difference applied to the valve disc 5 from the first direction side L1 through the valve seat opening 33 cannot push back the force of the valve disc biasing member 6 biasing the valve disc 5 toward the first direction side L1, and the valve disc 5 closes the valve seat opening 33, and the flow of the fluid F is blocked. In this way, the valve 1 has a structure that prevents backflow of the fluid F from the outlet pipe 102 side to the inlet pipe 101 side.

[0049] (Valve 1 flow path opening / closing function and flow rate change function) FIG. 6 is an explanatory diagram of the flow path opening / closing function and flow rate changing function of the valve 1. In FIG. 6(a), the flow path is closed and fluid F does not flow, and in FIG. 6(b), the flow path is open and the flow rate is lower than the maximum flow rate. 6(c) shows a state in which the flow path is open and the fluid F is flowing at the maximum flow rate. Next, the flow path opening / closing function and flow rate changing function of the valve 1 will be explained using FIG.

[0050] In the valve 1 disposed between the inlet pipe 101 and the outlet pipe 102, the position of the piston 3 pressed by the usage operation interlocking member 92 changes when the operating member 9 is operated to change the inclination of the usage operation input member 91, causing the usage operation interlocking member 92 to rotate. As a result, the valve 1 exhibits a flow path opening and closing function by switching between an overlapping state and a non-overlapping state between the retraction port 23 of the piston frame 2 and the inlet port 36 of the piston 3, and a flow rate changing function that can change the flow rate of the flowing fluid F depending on the degree of overlap between the retraction port 23 of the piston frame 2 and the inlet port 36 of the piston 3.

[0051] 6(a) and 1, when the operation input member 91 is tilted to one side so that the second cam curved surface 92e of the operation interlocking member 92 contacts the top surface of the piston 3, the distance between the second cam curved surface 92e and the rotation shaft 9a is relatively long, and therefore the piston 3 is pushed by the second cam curved surface 92e and moves significantly toward the second direction side L2. When the piston 3 moves significantly toward the second direction side L2, the introduction port 36 no longer overlaps with the retraction port 23 of the piston frame 2, blocking the flow of fluid F between the retraction port 23 and the introduction port 36. The valve 1 is in a closed state in which no fluid F flows. Note that the operation interlocking member 92 is shaped so that in this closed state, the portion of the second cam curved surface 92e closest to the second direction side L2 contacts the top surface of the piston 3 (the top surface of the upstream chamber lid 37). Therefore, in the closed state, the fixation release body 7 is not pressed relative to the piston 3, and the valve element 5 is in a closed state. In other words, the usage operation interlocking member 92 is formed with a second cam curved surface 92e as a closed state contact surface that comes into contact with the piston 3 when the inlet 36 does not overlap with the retraction port 23 of the piston frame 2, and the operator can operate the usage operation input member 91 to a predetermined inclination to put the valve 1 into a closed state in which fluid F does not flow.

[0052] 6(b) and 2, when the usage operation input member 91 is raised from the closed state to the other side so that the second cam plane 92b of the usage operation interlocking member 92 contacts the top surface of the piston 3, the distance between the second cam plane 92b and the rotation shaft 9a becomes shorter than in the closed state, and the piston 3, pushed by the second cam plane 92b, moves slightly from the closed state toward the first direction side L1. When the piston 3 moves slightly from the closed state toward the first direction side L1, the introduction port 36 partially overlaps with the retraction port 23 of the piston frame 2, resulting in an intermediate open state in which the fluid F can flow from the retraction port 23 to the introduction port 36 at a flow rate corresponding to the diameter of the overlapping flow passages. In this intermediate open state, the planar second cam plane 92b of the usage operation interlocking member 92 simultaneously contacts the top surface of the piston 3 (the top surface of the upstream chamber lid 37) and the end surface of the pin exposed end 71 of the fixation release body 7. Therefore, in the intermediate open state, the sticking release body 7 is not pressed relative to the piston 3, so that the valve element 5 is closed when the pressure P1 in the inlet pipe 101 connected to the upstream connecting part 22 is greater than the pressure P2 in the outlet pipe 102 connected to the downstream connecting part 24 of the piston frame 2 and the pressure difference is not equal to or greater than the cracking pressure. In other words, the usage operation interlocking member 92 is formed with a second cam plane 92b as an intermediate open state contact surface among the open state contact surfaces that contact the sticking release body 7 when the valve element 5 is not pressed in or that does not contact the sticking release body 7 and contacts the piston 3 when the inlet 36 overlaps the retraction port 23 of the piston frame 2 to a range narrower than the maximum, and the operator can operate the usage operation input member 91 to a predetermined inclination to set the valve 1 to an intermediate open state that allows the fluid F to flow at a flow rate less than the maximum flow rate and also exhibits the backflow prevention function.

[0053] 6(c) and 3, when the usage operation input member 91 is tilted from the intermediate open state to the other side so that the first cam plane 92a of the usage operation interlocking member 92 contacts the top surface of the piston 3, the distance between the first cam plane 92a and the rotation shaft 9a becomes shorter than in the intermediate open state, and the piston 3, pushed by the first cam plane 92a, moves further from the intermediate open state toward the first direction side L1. When the piston 3 moves further toward the first direction side L1 from the intermediate open state, the introduction port 36 completely overlaps with the retraction port 23 of the piston frame 2, and the maximum open state is reached, allowing the fluid F to flow from the retraction port 23 to the introduction port 36 at a maximum flow rate. In this maximum open state, the first cam plane 92a of the usage operation interlocking member 92, which is formed in a flat shape, simultaneously contacts the top surface of the piston 3 (the top surface of the upstream chamber lid 37) and the end surface of the pin exposed end 71 of the fixation release body 7. Therefore, in the maximum open state, the sticking release body 7 is not pressed relative to the piston 3, so that the valve element 5 is closed when the pressure P1 in the inlet pipe 101 connected to the upstream connecting part 22 is greater than the pressure P2 in the outlet pipe 102 connected to the downstream connecting part 24 of the piston frame 2 and the pressure difference is not equal to or greater than the cracking pressure. In other words, the usage operation interlocking member 92 is formed with a first cam plane 92a as a maximum open state contact surface among the open state contact surfaces that contact the sticking release body 7 when the valve element 5 is not pressed in, or that does not contact the sticking release body 7 but contacts the piston 3 when the inlet port 36 is maximally overlapping with the retraction port 23 of the piston frame 2, and the operator can operate the usage operation input member 91 to a predetermined inclination to set the valve 1 to a maximum open state that allows the fluid F to flow at a maximum flow rate and also exhibits the backflow prevention function.

[0054] (Valve 1 disc sticking release function) Figure 7 is an explanatory diagram of the valve disc release function of the valve 1, with Figure 7(a) showing the state in which the valve disc 5 is waiting to be released, Figure 7(b) showing the state in which the valve disc 5 is in the process of being released, and Figure 7(c) showing the state in which the valve disc has just been released from its stuck state. Next, the valve disc release function of the valve 1 will be explained using Figure 7.

[0055] When the operator operates the operating member 9, the valve 1 exhibits a valve body unsticking function by forcibly pushing the unsticking body 7 relative to the piston 3 in a direction away from the valve seat 32 due to the shape of the portion of the operation interlocking member 92 closest to the second direction side L2.

[0056] More specifically, when the valve 1 is in the closed state, the portion of the second cam curved surface 92e of the usage operation interlocking member 92 closest to the second direction side L2 is in contact with the upper surface of the piston 3 (the upper surface of the upstream chamber lid 37). Therefore, in the closed state, as shown in Figure 7(a), the sticking release body 7 is not pressed relative to the piston 3, and the valve 1 is in a closed state with the valve element 5 in close contact with the valve seat 32. In other words, the usage operation interlocking member 92 is formed with the second cam curved surface 92e as a sticking release inoperative surface that comes into contact with the sticking release body 7 when the valve element 5 is not pressed in, or does not come into contact with the sticking release body 7. When the valve 1 is not in use, the operator operates the operating member 9 to close the valve 1, and the valve 1 is in a sticking release inoperative state in which the valve element 5 may stick to the valve seat 32.

[0057] When the valve 1 is used, the operating member 9 is operated by an operator to allow the flow of fluid F, and the valve 1 is switched from a closed state to a partially open state. During this switching, the usage operation interlocking member 92 passes through a state in which the portion of the second cam curved surface 92e furthest to the second direction side L2 contacts the end face of the pin exposed end portion 71 of the fixation release body 7, as shown in Figure 7(b). In this state, the portion of the second cam curved surface 92e furthest to the second direction side L2 presses the end face of the pin exposed end portion 71 of the fixation release body 7, and the fixation release body 7 is pressed relative to the piston 3, forcibly pushing the valve disc 5 away from the valve seat 32, and the valve 1 enters a state in which the valve disc 5 is separated from the valve seat 32. That is, the usage operation interlocking member 92 is formed with a second cam curved surface 92e as a stick-release operating surface that temporarily comes into contact with the stick-release body 7 when the valve disc 5 is pressed in. When the valve 1 is first used, the operator operates the operating member 9 to switch the valve from the closed state to the intermediate open state, and during this process, the valve enters a stick-release operating state in which the valve disc 5 is temporarily forcibly separated from the valve seat 32. Note that in the intermediate open state, as shown in FIG. 7(c), the portion of the second cam plane 92b of the usage operation interlocking member 92 closest to the second direction side L2 is in contact with the upper surface of the piston 3 (the upper surface of the upstream chamber lid 37). Therefore, in the intermediate open state, the stick-release body 7 is not pressed relative to the piston 3, as in the closed state. That is, the usage operation interlocking member 92 is formed with a second cam curved surface 92e as a stick-release non-operating surface that comes into contact with the stick-release body 7 when the valve disc 5 is not pressed in, or does not come into contact with the stick-release body 7. Therefore, the valve 1 is in the stick-release non-operating state even in the intermediate open state.

[0058] Furthermore, when changing the flow rate of the fluid F flowing through the valve 1 to the maximum flow rate, the operator operates the operating member 9 to switch the valve 1 from the intermediate open state to the maximum open state. During this switching, the usage operation interlocking member 92 passes through a state in which the portion of the first cam curved surface 92d closest to the second direction side L2 contacts the end face of the pin exposed end 71 of the sticking release body 7, just as when switching from the closed state to the intermediate open state. Therefore, the valve 1 is in a state in which the valve disc 5 is separated from the valve seat 32, just as when switching from the closed state to the intermediate open state. In other words, the usage operation interlocking member 92 is formed with the first cam curved surface 92d as a sticking release operating surface that temporarily contacts the sticking release body 7 that is pressing the valve disc 5. When changing the flow rate, the operator operates the operating member 9 to switch the valve 1 from the intermediate open state to the maximum open state, and during this process, the valve 1 enters a sticking release operating state in which the valve disc 5 is temporarily forcibly separated from the valve seat 32. In the fully open state, the portion of the first cam plane 92a of the usage operation interlocking member 92 closest to the second direction side L2 is in contact with the upper surface of the piston 3 (the upper surface of the upstream chamber lid 37). Therefore, even in the fully open state, as in the intermediate open state, the sticking release body 7 is not pressed relative to the piston 3. In other words, the usage operation interlocking member 92 is formed with the first cam plane 92a as a sticking release inoperative surface that comes into contact with the sticking release body 7 when the valve disc 5 is not pressed in, or does not come into contact with the sticking release body 7, and the valve 1 is in the sticking release inoperative state even in the fully open state.

[0059] (Use of valve 1) As described above, when using the valve 1 having the valve disc release function, the valve disc 5 is always forcibly released from its stuck state by operating the operating member 9. For this reason, the valve 1 is effective when incorporated into a vacuum pump and used as a gas ballast valve that introduces gas as the fluid F by utilizing the pressure difference between atmospheric pressure and the negative pressure in the pump chamber.

[0060] (Actions and Effects) The valve 1 according to the embodiment is a valve with a backflow prevention function, comprising: a backflow prevention downstream frame 3A that defines a valve chamber 31 that is formed with a valve seat orifice 33 surrounded by a valve seat 32 and communicates with an upstream flow path via the valve seat orifice 33; and a valve disc 5 that is disposed within the valve chamber 31 and is movable between a state in contact with the valve seat 32 and a state away from the valve seat 32. The valve 1 also comprises a sticking release body 7 that penetrates the wall of the backflow prevention downstream frame 3A so that its tip can come into contact with the valve disc 5, and that is capable of pushing the valve disc 5 in a direction away from the valve seat 32 when a force is applied from outside the backflow prevention downstream frame 3A. Therefore, when a force is applied to the sticking release body 7 from outside, the valve disc 5 can be forcibly moved away from the valve seat 32, thereby releasing the sticking of the valve disc 5. Furthermore, the valve 1 is equipped with a use operation interlocking member 92 which is a member that interlocks with the operation of the operator when putting the valve 1 into a use state, is arranged so as to be able to come into contact with the sticking release body 7, and has a form that can temporarily increase the force applied to the sticking release body 7 during the operation process by the operator, so that the valve disc 5 is forcibly released when used, and there is almost no risk of the valve disc becoming stuck when in use. Therefore, if the valve 1 is configured as in the embodiment, it is possible to provide a valve with a backflow prevention function that reduces the risk of the valve disc becoming stuck when it is actually time to use it.

[0061] Furthermore, the configuration of the valve 1 further includes a valve body biasing member 6 that is disposed within the valve chamber 31 and constantly biases the valve body 5 toward the valve seat 32, thereby reliably pressing the valve body 5 against the valve seat 32 except when the fluid F is flowing forward, thereby more reliably preventing backflow of the fluid F.

[0062] The valve 1 further includes a backflow prevention upstream frame 3B, which is located upstream of the backflow prevention downstream frame 3A and has an inlet 36 for introducing fluid F, and which defines an upstream chamber 35 that communicates with the valve chamber 31 via the valve seat opening 33. The sticking release body 7 has a pin shape and is movably disposed within the backflow prevention upstream frame 3B, with a small-diameter portion 73 on one end penetrating the valve seat opening 33 so as to be able to protrude from the valve seat opening 33 into the valve chamber 31, and an end face of an exposed end portion 71 on the other end exposed to the first direction side L1 so as to face the usage operation interlocking member 92. In addition, in the valve 1, a portion of the upstream chamber 35 forms a flow path for flowing fluid F from the inlet 36 to the valve seat opening 33. That is, according to the configuration of the valve 1, the sticking release body 7 is disposed within the flow path, and therefore the sticking release body 7 does not protrude from the side, allowing for a more compact design.

[0063] Furthermore, according to the configuration of the valve 1, it is further provided with a sticking release body biasing member 8 which is arranged in the upstream chamber 35 and which constantly biases the sticking release body 7 towards the operation interlocking member 92, and the sticking release body biasing member 8 moves the sticking release body 7 in a direction away from the valve body 5 except when the sticking of the valve body 5 is to be forcibly released, thereby reducing the risk of the valve body 5 failing to close due to malfunction when the backflow prevention function should be exerted.

[0064] Furthermore, in the valve 1, the valve chamber 31 and the upstream chamber 35 are coaxially defined around the axis L, the valve element 5 has a rotationally symmetrical shape with its center of gravity located on the axis L when in contact with the valve seat 32, and the portion of the sticking release body 7 located within the upstream chamber 35 has a rotationally symmetrical shape with its center of gravity located on the axis L and movable along the axis L. With such a configuration of the valve 1 along the axis L, the valve element 5 and the sticking release body 7 are less likely to be subjected to biased force from the fluid F when they operate, allowing them to perform their backflow prevention function more stably and also being advantageous in terms of size and slimming.

[0065] The valve 1 also includes a piston frame 2 having a frame shape with an upstream connection section 22 formed therein for connecting an inlet pipe 101 for introducing a fluid from the outside. The piston frame 2 defines a piston chamber 21 that communicates with the inlet pipe 101, which is connected to the upstream connection section 22 via an inlet port 23, which is a through-hole. The backflow prevention downstream frame 3A and the backflow prevention upstream frame 3B are integrated to form a piston 3 that is movably disposed within the piston chamber 21. The piston 3 is shaped so that its outer wall surface is in close contact with at least the inner wall surface around the inlet port 23 and can move along the inner wall surface. The piston 3 is positioned so that the inlet port 36 switches between overlapping and non-overlapping states with the inlet port 23 as it moves. This configuration of the valve 1 allows the inlet port 23 and the inlet port 36 to switch between overlapping and non-overlapping states, thereby providing both a backflow prevention function and a flow path opening and closing function. This eliminates the need for a valve with a backflow prevention function and a separate valve with a flow path opening and closing function, thereby reducing the installation space required for fluidic devices requiring these functions.

[0066] Furthermore, the configuration of the valve 1 allows it to perform a flow path opening and closing function, as well as change the degree of overlap between the inlet 23 and the introduction port 36, thereby providing a flow rate changing function that can change the flow rate of the flowing fluid F, thereby making it possible to adjust the flow rate of the fluid F appropriately depending on the situation.

[0067] Furthermore, according to the configuration of the valve 1, it is provided with a piston biasing member 4 that is arranged in the piston chamber 21 and constantly biases the piston 3 toward the usage operation interlocking member 92, and the piston 3 is constantly pressed against the usage operation interlocking member 92, so that various functions can be performed without malfunction by operating the operating member 9 by the operator.

[0068] Furthermore, with the configuration of the valve 1, the center axes of the sticking release body 7, the valve body 5, and the piston 3 are all coaxial, so that the valve 1 can be made slimmer.

[0069] Furthermore, as described above, the valve 1 employs a rotating cam shape with a non-stick release operating surface and a stick release operating surface formed as the use operation interlocking member 92 of the operating member 9, which rotates when operated, and the surface that comes into contact with the stick release body 7 switches in turn to the non-stick release operating surface, the stick release operating surface, and the stick release non-operating surface. With this configuration of the use operation interlocking member 92, the valve disc 5 can be forcibly released from sticking with little force using this principle each time it is used, resulting in a valve with a backflow prevention function that reduces the risk of the valve disc 5 becoming stuck when it is time to use it.

[0070] Furthermore, as described above, the valve 1 employs a rotating cam-shaped operation interlocking member 92 in the operating member 9, in which a closed state contact surface, an intermediate open state contact surface, and a maximum open state contact surface are formed, and a sticking release operating surface is formed between adjacent contact surfaces among the closed state contact surface, the maximum open state contact surface, and the intermediate open state contact surface, and the operation interlocking member 92 rotates as the operation is performed, so that the surface that comes into contact with the piston 3 can be switched between the closed state contact surface, the maximum open state contact surface, and the maximum open state contact surface. With this configuration of the operation interlocking member 92, the piston 3 can be pushed in with little force using the principle of leverage, making it easy to open / close and change the flow rate, and the valve disc 5 is forcibly released from sticking during the operation process, resulting in a valve in which the risk of the valve disc 5 sticking is reduced.

[0071] Moreover, the valve 1 is mounted on a vacuum pump, for example, to control the flow of fluid F flowing inside the vacuum pump. In particular, it is highly useful as a gas ballast valve for the vacuum pump. Due to the effects of the valve 1 described above, a vacuum pump equipped with the valve 1 becomes a vacuum pump that is less likely to malfunction due to valve malfunction.

[0072] (Other forms) Although the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment and can be embodied in various forms without departing from the spirit of the present invention, and for example, the following modifications are also possible.

[0073] (1) The number, material, position, size, shape, function, etc. of the components described in the above embodiment are examples and can be changed within the scope that does not impair the effects of the present invention.

[0074] (2) In the above embodiment, the valve disc 5 is described as having a spherical shape, but the present invention is not limited to this. The valve disc may have any shape as long as it contacts the valve seat and closes the valve seat opening. For example, the valve disc may have a plate-like shape whose surface is shaped to conform to the valve seat, or a rod-like shape whose surface is shaped to conform to the valve seat. Note that the valve disc and the valve seat preferably have rotationally symmetric shapes about the axis so that they can contact with the periphery of the valve seat opening with uniform contact pressure.

[0075] (3) In the above-described embodiment, the piston biasing member 4, the valve body biasing member 6, and the sticking release body biasing member 8 are described as coil springs, but the present invention is not limited to this. Each biasing member may be, for example, a leaf spring, a rubber elastic body, or the like, as long as it can constantly bias the object to be biased in a predetermined direction. Furthermore, the valve body biasing member may not be provided in a structure in which the valve body is moved by pressure alone, and the sticking release body biasing member may not be provided in a structure in which there is no need to consider the risk of actively pushing the valve body when the backflow prevention function is not being exercised.

[0076] (4) In the above embodiment, the piston frame 2 and the piston 3 are described as being substantially cylindrical, but the present invention is not limited to this. For example, a cylindrical piston chamber may be formed in a rectangular parallelepiped piston frame, or the piston chamber may be formed in an elliptical shape, and the piston may be formed in an elliptical cylindrical shape to match the piston.

[0077] (5) In the above embodiment, the upstream connecting portion 22 for connecting the inlet pipe 101 is a recessed portion, and the downstream connecting portion 24 for connecting the outlet pipe 102 is a protruding portion. However, the present invention is not limited to this. The upstream connecting portion may be formed as a protruding portion, and the downstream connecting portion may be formed as a recessed portion.

[0078] (6) In the above embodiment, the sticking release function has been described as being applied to a valve 1 that has a backflow prevention function as well as an opening / closing function and a flow rate adjustment function by configuring the piston 3 to be movable, but the present invention is not limited to application to valves that integrate these functions. The configuration for realizing the sticking release function according to the above embodiment can also be applied to a valve that has only a backflow prevention function.

[0079] (7) In the above embodiment, the fixing release body 7 is described as being pin-shaped and disposed in the flow path inside the piston 3, but the present invention is not limited to this. It is also possible to configure the fixing release body to be disposed outside the flow path and to push the valve body through a through-hole provided separately from the flow path in the backflow prevention downstream frame.

[0080] (8) In the above embodiment, the operating member 9 is described as having the operation interlocking member 92 in the shape of a rotating cam, but the present invention is not limited to this. For example, the operation interlocking member may be configured in the shape of a rack via a gear and reciprocate relative to the operation input member.

[0081] (9) In the above embodiment, the usage operation interlocking member 92 has been described as having a rotating cam shape of a substantially right-angled triangle. However, the present invention is not limited to a usage operation interlocking member having a substantially right-angled triangle shape. For example, the usage operation interlocking member may have a rotating cam shape of a substantially square, pentagonal, or polygonal shape with more than two sides, and may be configured to change the overlap between the retraction port and the introduction port in multiple stages. Furthermore, the usage operation interlocking member may have a rotating cam shape of an eccentric ellipse, and may be configured to change the overlap between the retraction port and the introduction port in a continuous manner.

[0082] (10) In the above embodiment, the valve element 5 is closed when the portion of the second cam curved surface 92e closest to the second direction side L2 contacts the upper surface of the piston 3 (upstream chamber lid 37) in the closed state, but the present invention is not limited to this. In the closed state, the inlet port and the inlet port do not overlap and fluid F does not flow even if the valve element 5 is not closed. Therefore, in the closed state, the portion of the second cam curved surface closest to the second direction side L2 may contact the end face of the pin exposed end of the fixation release body to open the valve element.

[0083] (11) In the above embodiment, the fixing release body 7 has a pin shape that is rotationally symmetric about the axis L and is movable along the axis L within the upstream backflow prevention frame 3B, but the present invention is not limited to this. For example, the following modifications are also possible.

[0084] FIG. 8 is a cross-sectional view showing modified examples of the fixation release body. FIG. 8(a) shows an example in which the central axes of the valve element and the fixation release body are offset, and FIG. 8(b) shows an example in which the tip portion has a rotationally asymmetric shape. For example, the small-diameter pin portion 173 that contacts the valve element 105 of the fixation release body 107 as a first modified example shown in FIG. 8(a) has the same shape as the small-diameter pin portion 73 of the fixation release body 7 of the above embodiment, but its center of gravity is movable along the axis L, which is located at a position slightly offset from the axis L. In other words, the small-diameter pin portion 173 of the fixation release body 107 has a central axis that is offset from the center of the valve element 105 that is to be pushed out. Furthermore, for example, the small-diameter pin portion 273 that contacts the valve element 205 of the fixation release body 207 as a second modified example shown in FIG. 8(b) has a rotationally asymmetric shape, and its tip is offset from the axis L. As in these modified examples, by configuring the tip of the release body to press a position offset from the center of the spherical valve body, a force can be applied to the valve body to cause it to rotate, which makes it easier to release the valve body from the valve seat, which is preferable. [Explanation of symbols]

[0085] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C... valve, 2... piston frame, 2A... first piston frame, 2B... second piston frame, 3... piston, 3A... backflow prevention downstream frame, 3B... backflow prevention upstream frame, 4... piston biasing member, 5, 105, 205... valve body, 6... valve body biasing member, 7, 107, 207... sticking release body, 8... sticking release body biasing member, 9... operating member, 9a... rotating shaft, 10... cover, 21, 21A, 21B ...piston chamber, 22...upstream connection portion, 23...inlet port, 24...downstream connection portion, 25...outlet port, 31...valve chamber, 32...valve seat, 33...valve seat port, 34...valve chamber lid, 35...upstream chamber, 35a...first upstream chamber, 35b...second upstream chamber, 36...inlet port, 37...upstream chamber lid, 71...exposed end of pin, 72...pin flange portion, 73, 173, 273...pin narrow diameter portion, 91...usage operation input member, 92...usage operation interlocking member, 92a : First cam flat surface, 92b... second cam flat surface, 92c... third cam flat surface, 92d... first cam curved surface, 92e... second cam curved surface, 100... fluid device, 101... inlet pipe, 102... outlet pipe, F... fluid, L... axis line, L1... first direction side, L2... second direction side, L3... lever axis line, P1, P2... pressure, S, S1, S2... sealing member

Claims

1. A valve having a backflow prevention function in which a flow path through which a fluid flows is formed inside, a backflow prevention downstream frame having a frame shape with a valve seat opening at an end where the flow path diameter is reduced and surrounded by a valve seat, the frame defining, by an inner wall surface, a valve chamber which is an internal space communicating with an upstream flow path via the valve seat opening; a valve element disposed in the valve chamber so as to be movable between a state in contact with the valve seat and a state away from the valve seat, the valve element having a shape that closes the valve seat opening when in contact with the valve seat; a release body that penetrates the wall of the backflow prevention downstream frame and has a tip that can come into contact with the valve body, and that can press the valve body in a direction away from the valve seat when a force is applied from outside the backflow prevention downstream frame; a use operation interlocking member that is a member that is interlocked with at least an operation by an operator when the valve is put into a use state, that is arranged so as to be able to come into contact with the fixation release body, and that has a form that can temporarily increase the force applied to the fixation release body during the operation process by the operator; A valve comprising:

2. 2. The valve of claim 1, The valve further comprises a valve body biasing member disposed within the valve chamber and constantly biasing the valve body toward the valve seat.

3. 2. The valve of claim 1, the valve seat opening is connected to the valve chamber via the valve seat port; and the valve seat port is connected to the valve chamber via the valve seat port. The valve seat port is connected to the valve chamber via the valve seat port. The valve seat port is connected to the valve chamber via the valve seat port. the fixation release body has a pin shape, and is disposed movably within the backflow prevention upstream frame body with one end thereof penetrating the valve seat opening so as to be able to protrude from the valve seat opening into the valve chamber, and the other end thereof facing the operation interlocking member so as to be exposed when viewed from outside the upstream chamber, A valve in which a portion of the upstream chamber forms a part of a flow path for flowing fluid from the inlet to the valve seat port.

4. 4. The valve according to claim 3, The valve further comprises a release body biasing member disposed in the upstream chamber and constantly biasing the release body toward the use operation interlocking member.

5. 4. The valve according to claim 3, the valve chamber and the upstream chamber are each defined coaxially by an inner wall surface having a rotationally symmetrical shape, the center of which is an imaginary axis line extending in a straight line; the valve element has a rotationally symmetric shape, and the center of gravity of the valve element is located on the axis when the valve element is in contact with the valve seat; A valve in which at least the portion of the release body located within the upstream chamber has a rotationally symmetrical shape, the center of gravity of which is positioned on the axis or at a position slightly offset from the axis, and the center of gravity of which is movable along the axis.

6. 6. The valve according to claim 5, The valve, wherein the tip portion of the fixation release body on one end side has a rotationally asymmetric shape, and the position of the most distal end is off the axis line.

7. 4. The valve according to claim 3, a piston frame having a frame shape in which a connection part is formed for connecting an introduction pipe for introducing a fluid from the outside, the piston frame defining, by an inner wall surface, a piston chamber which is an internal space communicating with the introduction pipe connected to the connection part via a lead-in port which is a through hole, the backflow prevention downstream frame and the backflow prevention upstream frame are integrated together to form a piston that is disposed in the piston chamber, the piston has a shape capable of reciprocating along the inner wall surface with an outer wall surface in close contact with at least the inner wall surface around the inlet, and is arranged so that the introduction port switches between an overlapping state and a non-overlapping state with the inlet as it moves, The valve further has a flow path opening and closing function by switching between an overlapping state and a non-overlapping state of the inlet port of the piston frame and the inlet port of the piston.

8. 8. The valve of claim 7, The valve further has a flow rate changing function that can change the flow rate of the flowing fluid depending on the degree of overlap between the retraction port of the piston frame and the introduction port of the piston.

9. 8. The valve of claim 7, The valve further comprises a piston biasing member disposed in the piston chamber and constantly biasing the piston toward the usage operation interlocking member.

10. 8. The valve of claim 7, A valve in which the central axes of the sticking release body, the valve body, and the piston are coaxial.

11. 2. The valve of claim 1, The operation interlocking member has a rotating cam shape that has at least a non-stick release operating surface that contacts the stick release body when the valve body is not pushed in or does not contact the stick release body, and a stick release operating surface that contacts the stick release body when the valve body is pushed in, and rotates when operated, so that the surface that contacts the stick release body switches in turn from the stick release non-operating surface, the stick release operating surface, and the stick release non-operating surface.

12. 8. The valve of claim 7, The operation interlocking member has a rotating cam shape formed with a closed state contact surface that contacts the piston when the inlet is not overlapping the retraction port of the piston frame, an open state contact surface that contacts the sticking release body when the valve body is not pushed in or that does not contact the sticking release body and contacts the piston when the inlet overlaps the retraction port of the piston frame, and a sticking release operating surface that contacts the sticking release body when the valve body is pushed in between the closed state contact surface and the open state contact surface, and rotates when operated, so that the surface that contacts the piston can be switched between the closed state contact surface and the open state contact surface.

13. 9. The valve of claim 8, the operation interlocking member has a rotating cam shape on which are formed: a closed state contact surface that contacts the piston when the introduction port is not overlapping with the retraction port of the piston frame; a maximum open state contact surface that contacts the sticking release body when the valve body is not pushed in or when the introduction port is not in contact with the sticking release body and overlaps the retraction port of the piston frame to the maximum extent; an intermediate open state contact surface that contacts the sticking release body when the valve body is not pushed in or when the introduction port is not in contact with the sticking release body and overlaps the retraction port of the piston frame to a smaller extent than the maximum; and a sticking release operating surface that contacts the sticking release body when the valve body is pushed in between adjacent contact surfaces among the closed state contact surface, the maximum open state contact surface, and the intermediate open state contact surface; and the operation interlocking member rotates when operated, so that the surface that contacts the piston can be switched between the closed state contact surface, the maximum open state contact surface, and the maximum open state contact surface.

14. A vacuum pump equipped with the valve according to any one of claims 1 to 13 as at least one valve for controlling the flow of a fluid flowing inside the vacuum pump.

15. 15. The vacuum pump of claim 14, A vacuum pump, wherein the at least one valve is a gas ballast valve.

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