valve

Abstract

To provide technique enabling high durability and the adjustment of flow volume.SOLUTION: A valve 1 which can be mounted to a flexible tube C in which fluid flows is provided, which includes: a housing 10 formed with a through-hole 110 through which the tube C can be inserted; an annular recessed portion 112 formed in the inner periphery wall of the through-hole 110 and defining an input space S between the tube C being inserted thorough the through-hole 110 and the annular recessed portion 112; an input port 114 communicated with the input space S and used for applying control pressure to the input space S; a valve element 20 which can fixed to a position in contact with the input space S in the tube C; a flow path defining portion provided in the valve element 20 and defining a gap flow path FP between a peripheral wall part C1 of the tube C and the valve element 20; and a protrusion located in the gap flow path FP and protruded in the radial direction of the tube C to narrow a part of the gap flow path FP, for opening / closing the gap flow path FP according to the flexion of the peripheral wall portion C1 which is based on the control pressure applied to the input space S.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a valve for controlling the flow rate of a fluid. [Background technology]

[0002] A conventionally known type of valve is the pinch valve. A pinch valve closes a tube through which a control fluid flows, particularly a tube made of a highly elastic material such as silicone rubber, by mechanically compressing the tube from the outside with a pinch member such as a plunger, causing elastic deformation. To open the valve, the pinch member is simply returned to its original position, allowing the tube to return to its original state due to its elastic force.

[0003] Related technologies include a pinch valve that increases versatility and expandability by expanding the types and sizes of elastic tubes that can be used, and also increases the stability and reliability of operation by reliably applying pressure to the elastic tube (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-066419 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the pinch valve described above does not have a stagnation area for fluid, the opening and closing operations can cause stress to accumulate in the pinch valve components, such as the pinch member and its drive mechanism, resulting in a problem in that repeated opening and closing operations can reduce durability.

[0006] The problem to be solved by the embodiments of the present invention is to provide a technology that is highly durable and allows the flow rate of a fluid to be adjusted. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the present invention is a valve that can be attached to a flexible pipe through which a fluid flows, the valve comprising: a housing having an insertion hole through which the pipe can be inserted; a recess formed in an inner wall of the insertion hole and defining an input space between the housing and the pipe when the pipe is inserted into the insertion hole; an input port that communicates with the input space and applies a control pressure to the input space; a valve body that can be fixed at a position within the pipe that is in contact with the input space; a flow path defining portion that is provided on the valve body and defines a gap flow path between the valve body and a wall portion of the pipe; and a protrusion that is located within the gap flow path and protrudes radially from the pipe so as to narrow a portion of the gap flow path, and that opens and closes the gap flow path in response to deflection of the wall portion based on the control pressure applied to the input space. [Effects of the Invention]

[0008] According to an embodiment of the present invention, it is possible to provide a technology that allows for adjustment of the flow rate of a fluid with high durability. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic perspective view showing the configuration of a valve according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a schematic vertical cross-sectional view of a valve body according to the embodiment. [Figure 4] FIG. 2 is a schematic plan view of a valve body according to the embodiment. [Figure 5] FIG. 4 is a diagram for explaining a valve when the control pressure according to the embodiment is 0%. [Figure 6] FIG. 10 is a diagram illustrating a valve according to the embodiment when the control pressure is 50%. [Figure 7] FIG. 4 is a diagram for explaining a valve according to the embodiment when the control pressure is 100%. [Figure 8]FIG. 4 is a diagram showing the relationship between the control pressure and the valve opening degree in the valve according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (Overall valve configuration) The overall configuration of the valve according to this embodiment will be described. Fig. 1 is a schematic perspective view showing the configuration of the valve according to this embodiment. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Fig. 3 is a schematic longitudinal cross-sectional view of the valve body according to this embodiment, and Fig. 4 is a schematic plan view of the valve body according to this embodiment. Note that Figs. 2 and 3 show a cross section of the valve 1 cut by imaginary plane A shown in Fig. 1, viewed from the lower right in the figure. For the sake of explanation, Fig. 2 shows only the valve body 20, which is not cut, and shows its side surface.

[0012] 1 and 2, the valve 1 according to this embodiment includes a housing 10 that can be attached to a flexible tube C through which a main fluid such as a gas or liquid flows, and a valve element 20 that can be placed in the tube C located inside the housing 10. Note that the symbol F in FIG. 1 indicates the flow direction of the main fluid flowing through the tube C. For the sake of explanation, the input port 114 side shown in FIG. 1 is defined as the upper side, and the downstream side of the housing 10 in the flow direction F on a plane extending perpendicular to the flow direction F is defined as the front side, and the upstream side is defined as the back side. Therefore, the front-to-rear direction defined by the front and back sides of the valve 1 coincides with the flow direction F.

[0013] (Housing 10) The housing 10 is formed in a rectangular shape that is long in the flow direction F of the main fluid, i.e., in the front-to-rear direction, and is provided with a through-hole 110 that penetrates from approximately the center of the front face to approximately the center of the back face. The through-hole 110 is adapted to allow a tube C to be inserted therethrough, and preferably has a diameter that allows airtight contact with the outer peripheral surface of the tube C at least on the front and back sides when the tube C is inserted.

[0014] An annular recess 112 is formed in the peripheral wall of the through hole 110 at approximately the center in the front-rear direction. The annular recess 112 is spaced apart from a portion of the peripheral wall of the tube C that faces it in the radial direction (hereinafter referred to as peripheral wall portion C1). Therefore, an input space S, the details of which will be described later, is defined between the annular recess 112 and the outer peripheral wall of the peripheral wall portion C1 of the tube C.

[0015] An input port 114 is formed on the upper surface of the housing 10. The input port 114 is a hole for supplying a fluid (hereinafter referred to as a control fluid) such as a gas to control the operation of the valve 1, i.e., to adjust the valve opening of the valve element 20 of the valve 1. The input port 114 is preferably configured to be connectable to a supply device (not shown), such as a pump, that can supply the control fluid. The input port 114 extends substantially vertically downward from the upper surface and has a first hole 116 located on the upper surface side and a second hole 118 connected to the lower end of the first hole 116, communicating with the first hole 116 and having a smaller diameter than the first hole 116. The lower end of the second hole 118 is connected to the annular recess 112. Therefore, the input port 114 is fluidly connected to the input space S.

[0016] (Valve body 20) 2, the valve element 20 is formed in a long, approximately cylindrical shape extending in the flow direction F, and serves to open and close the tube C in response to the pressure of the control fluid supplied from the input port 114. As shown in FIGS. 3 and 4, the valve element 20 has an upstream fixed portion 22 located at the upstream end in the flow direction F, a downstream fixed portion 24 located at the downstream end, and a flow path defining portion 26 located between the upstream fixed portion 22 and the downstream fixed portion 24.

[0017] The upstream fixing portion 22 and the downstream fixing portion 24 are each formed in a substantially cylindrical shape with a central axis direction parallel to the flow direction F, and their central axes are aligned with each other. Preferably, the central axis position is aligned with the central axis position of the tube C when the valve element 20 is disposed in the tube C. The upstream fixing portion 22 and the downstream fixing portion 24 each have the same diameter φD0, and each preferably has a length that allows the valve element 20 to be fixed to the tube C. For example, the diameter φD0 of each of the upstream fixing portion 22 and the downstream fixing portion 24 is substantially the same as the inner diameter φD of the tube C, preferably a length that is approximately 100 μm smaller than the inner diameter φD of the tube C. Therefore, the valve element 20 is fixed in the tube C such that the outer circumferential surfaces of the upstream fixing portion 22 and the downstream fixing portion 24 uniformly abut against the inner circumferential wall of the tube C, making it substantially impossible for the valve element 20 to move in the flow direction F. In other words, the valve element 20 is fixed in the tube C so that it remains stationary due to the biasing force in the flow direction F generated by the flow of the main fluid.

[0018] The upstream fixed part 22 has a recess 222 formed in the upstream end face thereof, which is recessed in the flow direction F in a quadrangular pyramid shape. Two upstream inclined flow channels 224, which gradually slope upward or downward along the flow direction F, are formed at the upper and lower parts of the circumferential surface of the recess 222. The upstream ends of the two upstream inclined flow channels 224 are each connected to the recess 222. The downstream ends of the upstream inclined flow channels 224 are each connected to a gap flow channel FP (see FIG. 2), which will be described in detail later. Specifically, the downstream end of the upstream fixed part 22 has an annular inclined surface 226 formed thereon, which is inclined so as to gradually decrease in diameter toward the flow direction F. The downstream openings of the two upstream inclined flow channels 224 are formed on the inclined surface 226. Since the gap between the outer peripheral surface of the upstream fixed part 22 and the inner peripheral surface of the tube C is closed, the main flow in the tube C flows into the recess 222 and then flows into the gap flow path FP via the two upstream inclined flow paths 224. Naturally, the sum of the diameters of the upstream inclined flow paths 224 is smaller than the diameter of the flow path of the tube C upstream of the valve body 20 (the inner diameter of the tube C). As a result, the recess 222 and the upstream inclined flow paths 224 can narrow the flow path of the tube C, that is, can function as an orifice.

[0019] The downstream-side fixed part 24 has a recess 242 formed in a quadrangular pyramid shape on its downstream end face, recessed in the opposite direction to the flow direction F. Two downstream-side inclined flow channels 244, which gradually slope upward or downward in the opposite direction to the flow direction F, are formed at the upper and lower parts of the circumferential surface of the recess 242. The upstream ends of the two downstream-side inclined flow channels 244 are connected to the gap flow channel FP. Specifically, the upstream end of the downstream-side fixed part 24 has an annular inclined surface 246 formed thereon, which gradually reduces in diameter in the opposite direction to the flow direction F. The upstream openings of the upstream-side inclined flow channels 224 are formed on the inclined surface 246. The downstream ends of the two downstream-side inclined flow channels 244 are connected to the recess 242. As with the upstream side, the gap between the outer circumferential surface of the downstream fixed part 24 and the inner circumferential surface of the tube C is blocked, so that the main fluid in the gap flow passage FP flows into the recess 242 via the two downstream inclined flow passages 244 and is discharged downstream of the valve body 20. From the viewpoint of discharging the main fluid in the gap flow passage FP, it is preferable that the diameter of each downstream inclined flow passage 244 be equal to or greater than the diameter of each upstream inclined flow passage 224. Therefore, the inclined surface 246 on which the upstream opening of each downstream inclined flow passage 244 is formed is longer in the flow direction than the inclined surface 226 on which the downstream opening of each upstream inclined flow passage 224 is formed.

[0020] The flow path defining portion 26 has a cylindrical body 262 whose central axis direction is parallel to the flow direction F and whose central axis position is the same as that of the upstream fixed portion 22 and the downstream fixed portion 24, and an annular protrusion 264 that protrudes uniformly radially outward from the cylindrical body 262. The cylindrical body 262 has a diameter smaller than that of the upstream fixed portion 22 and the downstream fixed portion 24, and its upstream end is connected to the downstream end of the inclined surface 226 of the upstream fixed portion 22. Meanwhile, the downstream end of the cylindrical body 262 is connected to the upstream end of the inclined surface 246 of the downstream fixed portion 24. As a result, the cylindrical body 262 is positioned so that its central axis coincides with that of the tube C without coming into contact with the inner circumferential wall of the tube C. 2, the cylindrical body 262 can define an annular space between its own circumferential surface and the inner circumferential wall of the circumferential wall portion C1 of the tube C. In this embodiment, the annular space defined between the outer circumferential wall of the cylindrical body 262 and the inner circumferential wall of the circumferential wall portion C1 serves as the gap flow path FP.

[0021] The diameter of the upstream end of the inclined surface 246 of the downstream fixing part 24 is smaller than the diameter of the cylindrical body 262. Therefore, the downstream end of the cylindrical body 262 is connected to the inclined surface 246 of the downstream fixing part 24 and is formed as an inclined surface 266 whose diameter gradually decreases toward the flow direction F. It is preferable that this inclined surface 226 extend to the apex of the annular protrusion 264, i.e., the annular part of the annular protrusion 264 where the diameter is greatest, from the viewpoint of realizing a smooth flow of the main fluid, i.e., reducing retention of the main fluid. For the same reason, it is preferable that the upstream side of the annular protrusion 264 be formed as an inclined surface 268 whose diameter gradually decreases toward the opposite side of the flow direction F.

[0022] The annular protrusion 264 has a tip (apex) that is close to the inner circumferential wall of the circumferential wall portion C1 that defines the gap flow path FP in the tube C. In other words, the annular protrusion 264 uniformly protrudes radially outward from the circumferential surface of the cylindrical body 262. Therefore, the annular protrusion 264 narrows a portion of the gap flow path FP. In this embodiment, the annular protrusion 264 can open and close the gap flow path FP. Specifically, when a control fluid is supplied to the input port 114, the control fluid flows into the input space S. As described above, since the tube C is made of a flexible material, when the pressure of the control fluid (hereinafter referred to as the control pressure) increases while the control fluid flows into the input space S, the outer circumferential wall (see FIG. 2 ) of the circumferential wall portion C1 that defines the input space S in the tube C bends radially inward, i.e., toward the valve body 20, in response to the control pressure. When the inner circumferential wall of the circumferential wall portion C1 of the tube C bends until it contacts the annular protrusion 264, the gap flow path FP is closed. The opening and closing operation of the valve 1 will be described in detail later.

[0023] Next, we will explain in detail how the control fluid can control the valve opening of the valve 1. The force P1 applied to the peripheral wall C1 of the tube C by the main fluid flowing into the gap flow path FP is calculated using the following equation.

[0024]

number

[0025] 3, and indicates the diameter of the apex of the annular protrusion 264. L2, shown in FIG. 3, indicates the length in the flow direction F from the apex of the annular protrusion 264 to the upstream end of the inclined surface 226 of the upstream fixing part 22. P X indicates the internal pressure of the gap channel FP.

[0026] Next, the force P2 applied to the peripheral wall C1 of the tube C generated by the control fluid is calculated by the following formula.

[0027]

number

[0028] In the above formula (2), d is φd shown in FIG. 2, and represents the outer diameter of the gap flow path FP (the inner diameter of the peripheral wall portion C1 of the tube C). L1 is L1 shown in FIG. 3, and represents the length in the flow direction F from the downstream end of the inclined surface 246 in the downstream fixing portion 24 to the apex of the annular protrusion 264. P in represents the internal pressure (control pressure) of the input space S.

[0029] Since the force balance is established for the forces P1 and P2 applied to the tube C when L1 << L2, the following equation holds.

Equation

Equation

[0030] In the above formula (4), since the outer diameter d of the gap flow path FP, the diameter d0 of the tip of the annular protrusion 264, and the lengths L1 and L2 in the flow direction F are all constants, the internal pressure P of the gap flow path FP X is given by the following equation.

[0031]

Equation

[0032] In the above formula (5), C represents a variable related to the material of the main fluid or the tube C. According to this formula (5), the internal pressure P in the gap flow path FP X can be seen to be adjustable by the control pressure P in This also indicates that the flow rate of the main fluid and the pressure of the main fluid on the downstream side of the valve body 20 can also be adjusted by the control pressure P in .

[0033] [[ID=())) It is preferable to set the length of the valve element 20 so that the value of length L2 / length L1 is 10 or more. By setting the length in this manner, the relationship between the control pressure and the valve aperture of the valve element 20 is approximately linear. In other words, the valve aperture does not change abruptly in response to an increase or decrease in the control pressure, and the valve aperture can be appropriately increased or decreased in accordance with the degree of increase or decrease in the control pressure. This effect can be further enhanced by the fact that the gap flow path FP is formed approximately cylindrical, the annular protrusion 264 is formed annularly, and the input space S is formed cylindrically, thereby allowing the control pressure to be applied uniformly to the peripheral wall portion C1 of the tube C and the space between the annular protrusion 264 and the tip of the annular protrusion 264 to be uniformly narrowed.

[0034] (device operation) Next, the operation of the valve 1 according to this embodiment will be described in detail. FIG. 5 is a diagram illustrating the valve according to this embodiment when the control pressure is 0%, where (a) is a schematic vertical cross-sectional view, and (b) is a cross-sectional view taken along line BB in (a). FIG. 6 is a diagram illustrating the valve according to this embodiment when the control pressure is 50%, where (a) is a schematic vertical cross-sectional view, and (b) is a cross-sectional view taken along line CC in (a). FIG. 7 is a diagram illustrating the valve according to this embodiment when the control pressure is 100%, where (a) is a schematic vertical cross-sectional view, and (b) is a cross-sectional view taken along line DD in (a). FIG. 8 is a diagram showing the relationship between the control pressure and the valve opening in the valve according to this embodiment.

[0035] Of the main fluid in the tube C to which the valve 1 is attached, the main fluid in the gap flow path FP is reduced in pressure by passing through the recess 222 and the upstream inclined flow path 224 and flowing into the gap flow path FP, relative to the pressure on the upstream side of the valve element 20. The flowing main fluid passes through the gap gx (see FIG. 5 ) between the inner circumferential wall of the peripheral wall portion C1 and the annular protrusion 264, and is discharged to the downstream side of the valve element 20 via the downstream inclined flow path 244 and the recess 242. While the main fluid is flowing in this way, by supplying a desired control pressure to the input port 114, the valve aperture of the valve 1 can be controlled, and the flow rate of the main fluid can be appropriately adjusted.

[0036] 5, when the control pressure is 0%, that is, when the control fluid is not supplied to the input port 114 and does not flow into the input space S, no force acts to press the peripheral wall portion C1 of the tube C radially inward. Therefore, the gap gx between the inner peripheral wall of the peripheral wall portion C1 and the annular protrusion 264 becomes maximum, and therefore the flow rate of the main fluid in the gap flow path FP flowing out downstream from the gap gx also becomes maximum.

[0037] As shown in FIG. 6, when the control pressure is 50%, that is, when the control fluid is supplied to the input port 114 and the internal pressure P in When 50% of the control pressure is applied, a force is applied that presses the peripheral wall C1 of the tube C radially inward, causing the peripheral wall C1 to bend uniformly radially inward. The control pressure of 50% here should be understood to be half the pressure when the control pressure is 100%, as explained below.

[0038] The gap gx decreases due to the deflection. According to the valve 1 of this embodiment, the value of the gap gx, which is the result of the deflection being reduced, can be set to approximately 50% of the maximum value when the control pressure is 0%. In other words, the valve opening can be set to approximately 50% of the valve opening (100%) when the control pressure is 0%. At this time, the internal pressure P of the gap flow path FP X The force generated by the input space S and the internal pressure P in As a result, the following equation (6) is established, and therefore the following equation (7) is established.

[0039]

number

number

[0040] In the above formulas (6) and (7), L represents the total length of the valve body 20 in the flow direction F.

[0041] As shown in FIG. 7, when the control pressure is 100%, that is, when the control fluid is supplied to the input port 114 and the internal pressure P in When 100% of the pressure is applied, the force pressing the peripheral wall portion C1 of the tube C radially inward is maximized, causing the inner peripheral surface of the peripheral wall portion C1 to abut against the annular protrusion 264. This abutment causes the gap flow path FP to be liquid-tightly closed, and the valve opening degree becomes 0. Note that the 100% control pressure here is preferably set to a control pressure that is about 10% higher than the surface pressure (pressure on the peripheral wall portion C1) that seals the main flow path. This setting makes it possible to close the main flow path, i.e., close the gap flow path FP, with ample margin of error.

[0042] As described above, in the valve 1 according to this embodiment, the internal pressure P X As the pressure P increases, the gap gx decreases. X However, as mentioned above, the internal pressure P X and internal pressure P in There is a force equilibrium between X ≒P in Therefore, by adjusting the control pressure, the valve opening can be adjusted, and in turn, the output flow rate of the main fluid discharged from the valve 1 can be adjusted. As shown in Figure 8, the relationship between the control pressure and the valve opening (output flow rate: LPM) is approximately linear, meaning that the valve opening, i.e., the output flow rate of the main fluid, can be reduced in inverse proportion to an increase in the control pressure with good response.

[0043] According to the present embodiment described above, it is possible to appropriately and quickly control the output flow rate of the primary fluid with an extremely simple configuration. In particular, since the output flow rate can be controlled while balancing the forces generated by the primary fluid and the control fluid, it is possible to suppress the generation of localized loads on the valve 1, thereby achieving high durability. Furthermore, the structure is extremely simple, and in particular, the valve element 20 has no surfaces perpendicular to the fluid flow direction F, and only surfaces parallel to or inclined relative to the flow direction F, so that stagnation of the primary fluid does not occur. Therefore, the valve element 20 can be extremely easily cleaned.

[0044] Furthermore, the only elements that come into contact with the main fluid are the tube C and the valve element 20. This simplifies management, and the total cost, including parts, assembly, testing, etc., is extremely low. Furthermore, because the output flow rate of the main fluid is controlled by applying a control pressure from outside the tube C, the cleanliness of the main fluid is not reduced.

[0045] The material of the tube C can be appropriately selected depending on the intended use of the primary fluid. For example, assuming that the tube C is used to carry a primary fluid, such as a cleaning liquid required during semiconductor manufacturing, it is preferable that the tube C be made of a resin material with high durability, chemical resistance, non-stickiness, insulating properties, and low abrasion. Examples of such materials include fluororesins such as PFA (perfluoroalkoxyalkane), PTFE (polytetrafluoroethylene), and ETFE (tetrafluoroethylene-ethylene copolymer). The valve element 20, which contacts the primary fluid, can also be made of these materials. Using such materials can maintain a high level of cleanliness in the primary fluid, making it suitable for use in, for example, semiconductor manufacturing, where high levels of cleanliness are required. In other words, since the valve element 20 can be made of the same material as the tube C, the valve 1 according to this embodiment can maintain a higher level of cleanliness in the primary fluid. Of course, the valve element 20 does not necessarily have to be the same as the tube C, making it extremely versatile.

[0046] In this embodiment, the recesses 222 and 242 are described as being recessed in a quadrangular pyramid shape, but this is not limiting, and they may be recessed in a triangular pyramid shape or a conical (cone-shaped) shape.

[0047] The annular protrusion 264 may be provided on the inner circumferential wall of the circumferential wall portion C1 of the tube C. The upstream fixing portion 22, the downstream fixing portion 24, and the flow path defining portion 26 may be integrally formed or may be configured to be individually disassembled. The relationship between the control pressure and the valve aperture does not have to be linear. For example, the gap flow path FP may not be formed annularly but only in the upper portion, with the lower flow path portion being filled by the cylindrical body 262. In this case, the input space S may also not be formed annularly but only in the space facing the gap flow path FP. In such a configuration, the relationship between the control pressure and the valve aperture may not be approximately linear, but the function of decreasing the valve aperture as the control pressure increases can be achieved.

[0048] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents. [Explanation of symbols]

[0049] 1 valve 10. Housing 110 Through hole (insertion hole) 112 Annular recess (recess) 114 input ports 20 Valve body 22 Upstream fixed part 224 Upstream inclined channel 24 Downstream fixed part 244 Downstream inclined channel 26 Flow path dividing section 264 Annular protrusion (protrusion) C Tube (piping) C1 Peripheral wall (wall) FP pore flow channel S input space

Claims

1. A valve that can be attached to a flexible pipe through which a fluid flows, a housing having an insertion hole through which the piping can be inserted; a recess formed in an inner peripheral wall of the insertion hole, the recess defining an input space between the pipe inserted into the insertion hole and the pipe; an input port communicating with the input space for applying a control pressure to the input space; a valve body that can be fixed to a position in contact with the input space within the pipe; a flow path defining portion provided on the valve body and defining a gap flow path between the valve body and a wall portion of the pipe; a protrusion located within the gap flow path, protruding in a radial direction of the pipe so as to narrow a portion of the gap flow path, and configured to open and close the gap flow path in response to deflection of the wall portion based on a control pressure applied to the input space; A valve comprising:

2. the flow path defining portion has a cylindrical body located approximately at the center in the radial direction of the pipe, and the gap flow path is formed between the peripheral surface of the cylindrical body and the wall portion, The protrusion is formed in an annular shape on the circumferential surface of the cylindrical body.

2. The valve according to claim 1.

3. an upstream flow path that narrows the flow path of the piping and functions as an orifice is provided on the upstream side of the flow path defining portion; The fluid flows into the gap flow path via the upstream flow path.

2. The valve according to claim 1.

4. The valve body is the valve body further includes a cylindrical upstream fixing portion and a cylindrical downstream fixing portion, each of whose circumferential surfaces abuts against the inner circumferential surface of the wall portion to fix the valve body to the piping, and which are aligned along the flow direction of the fluid, with the flow path defining portion located between them; the upstream-side fixed portion is provided with the upstream-side flow path, The downstream fixed portion is provided with a downstream flow path for causing the fluid in the gap flow path to flow downstream of the valve body.

4. The valve according to claim 3.

5. the flow path defining portion is located approximately at the center in the radial direction of the pipe and has a cylindrical body having a smaller diameter than the upstream and downstream fixed portions, and the gap flow path is formed between a peripheral surface of the cylindrical body and the wall portion, The protrusion is formed annularly on the circumferential surface of the cylindrical body, When the distance from the upstream end of the downstream fixing portion to the apex of the protrusion is L1 and the distance from the downstream end of the upstream fixing portion to the apex of the protrusion is L2, the value obtained by dividing L2 by L1 is 10 or more.

5. The valve according to claim 4.

6. the flow path defining portion is located approximately at the center in the radial direction of the pipe and has a cylindrical body having a smaller diameter than the upstream and downstream fixed portions, and the gap flow path is formed between a peripheral surface of the cylindrical body and the wall portion, The protrusion is formed annularly on the circumferential surface of the cylindrical body, the upstream fixing portion has a downstream end formed as an inclined surface whose diameter gradually decreases toward the downstream side, and is connected to the flow path defining portion; the downstream fixing portion has an upstream end formed as an inclined surface whose diameter gradually decreases toward the upstream side, and is connected to the flow path defining portion; a downstream opening of the upstream flow path is formed on the inclined surface of the upstream fixed portion, The upstream opening of the downstream flow path is formed in the inclined surface of the downstream fixing portion.

5. The valve according to claim 4.

7. the input space extends along the flow direction of the fluid so as to cover a range from an upstream end of the inclined surface of the upstream fixed portion to a downstream end of the inclined surface of the downstream fixed portion.

7. The valve according to claim 6.

8. The surfaces of the flow path defining portion and the protrusion are parallel or inclined with respect to the direction of flow of the fluid. The valve according to any one of claims 1 to 7.

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