Vortex flow rate adjustment valve

Abstract

A vortex flow rate adjustment valve (11) comprises: a vortex chamber (27) that is defined by a cylindrical peripheral wall (13), and a first end wall (15) and a second end wall (17) provided at both ends of the peripheral wall (13); an inlet flow path (19) that extends along an inlet flow path center axis (P1) and opens into the peripheral wall (13); and an outlet flow path (21) that extends along an outlet flow path center axis (P2) and opens into the first end wall (15). The inlet flow path (19) is provided so that the inlet flow path center axis (P1) passes through a position away from a vortex chamber center axis (O) and the outlet flow path center axis (P2). The second end wall (17) is configured so as to be movable toward and away from the first end wall (15) by a drive unit. The flow rate of fluid flowing out from the outlet flow path is adjusted according to the amount of movement of the second end wall (17) with respect to the first end wall (15).

Description

Vortex flow control valve

[0001] The present invention relates to a flow control valve used in fluid transport piping in various industrial fields such as chemical plants, semiconductor manufacturing fields, liquid crystal manufacturing fields, and food manufacturing fields.

[0002] Needle valves are commonly used for flow rate adjustment in various industrial fields. As described in Patent Document 1, for example, a needle valve adjusts the flow rate of a fluid flowing through the gap between the needle and the valve seat by inserting the tapered tip of a valve element called a needle into a valve seat having a through-hole and moving the peripheral surface of the tip of the needle toward and away from the valve seat to change the gap between the needle and the valve seat. To enable fine adjustment of the flow rate, the gap between the needle and the valve seat in a needle valve is narrower than in other flow paths. In particular, the gap between the needle and the valve seat becomes very narrow near the lower limit of the needle valve's operating flow rate range.

[0003] Patent No. 5144880 Publication No. 59-5209

[0004] As described above, needle valves have a narrow gap between the needle and the valve seat, particularly near the lower limit of the needle valve's operating flow range. Therefore, if the needle and the valve seat are not coaxial, they may come into contact and slide when adjusting to a low flow rate, even though they should not. This can result in wear on the needle and the valve seat. Such wear changes the relationship between the needle and the valve seat, i.e., the needle valve's opening and flow rate, making it difficult to accurately adjust the flow rate. Furthermore, particles generated by wear can be mixed into the fluid. Such particle mixing into the fluid is a major problem, particularly in the semiconductor manufacturing industry. When an electric actuator is used to drive the needle and frequently adjust the flow rate using feedback control, the needle is constantly reciprocating, making the above-mentioned problem particularly pronounced. Furthermore, changes in the relationship between the needle valve's opening and flow rate require readjustment of control parameters, such as feedback control. In such cases, the needle valve is often replaced at the end of its useful life, resulting in increased maintenance costs.

[0005] One method for preventing sliding between the valve disc and the valve seat is to use a vortex-type fluid element utilizing a swirling flow, as disclosed in Patent Document 2, for example. The vortex-type fluid element disclosed in Patent Document 2 includes a vortex chamber having an outlet port at its center, an input nozzle connected to the outer periphery of the vortex chamber and directing the fluid from the input port toward the output port, and a control nozzle that ejects a control flow that swirls the fluid ejected from the input nozzle near the outlet of the vortex chamber. In the interference region, the control flow ejected from the control nozzle collides with the jet ejected from the input nozzle and deflects it, generating a vortex within the vortex chamber. Generating a vortex creates a pressure difference between the interference region and the output port, increasing flow resistance and thereby controlling the output flow rate. However, while this type of vortex-type fluid element does not cause contact between the valve disc and the valve seat, it is necessary to adjust the flow rate of the control flow ejected from the control nozzle in order to control the flow rate. Therefore, a flow rate control valve is required to adjust the flow rate of the control flow, and ultimately, there remains a risk of particles being mixed into the control flow.

[0006] Therefore, an object of the present invention is to solve the problems present in the prior art and to provide a flow control valve in which contact between the valve body and the valve seat does not occur within the area in contact with the fluid to be controlled.

[0007] In view of the above object, the present invention provides a vortex type flow control valve comprising: a vortex chamber defined by a cylindrical peripheral side wall and first and second end walls provided at both ends of the peripheral side wall and facing each other, and extending along a central axis of the vortex chamber; an inlet flow path extending along a central axis of an inlet flow path and opening at the peripheral side wall; and an outlet flow path extending along a central axis of an outlet flow path and opening at the first end wall, wherein a fluid flowing in from the inlet flow path forms a vortex flow within the vortex chamber and flows out of the outlet flow path, the inlet flow path being arranged such that the central axis of the inlet flow path passes through a position away from the central axis of the vortex chamber and the central axis of the outlet flow path, and the second end wall is configured to be movable by a drive unit so as to approach and move away from the first end wall, and the flow rate of the fluid flowing out of the outlet flow path is adjusted in accordance with the amount of movement of the second end wall relative to the first end wall.

[0008] In the above-described vortex flow control valve, a vortex chamber extending along the central axis of the vortex chamber is defined by a cylindrical peripheral wall and first and second end walls provided at both ends, facing each other. An inlet flow passage is provided so that the central axis of the inlet flow passage, which opens into the peripheral wall, passes through a position away from the central axis of the vortex chamber and the central axis of the outlet flow passage. An outlet flow passage opens into the first end wall. Thus, fluid flowing in from the inlet flow passage forms a swirling flow within the vortex chamber, flows in a vortex pattern, and then flows out of the outlet flow passage. As a result, pressure loss occurs depending on the length of the swirling flow (i.e., the length of the vortex flow streamline) and the flow velocity from the inlet flow passage to the outlet flow passage. Furthermore, when the second end wall defining the vortex chamber is moved toward or away from the first end wall by a drive unit, the height of the space through which the vortex flow can flow within the vortex chamber (i.e., the distance between the first and second end walls) changes, thereby increasing or decreasing the available area. As a result, the flow velocity of the vortex flow within the vortex chamber increases or decreases. As described above, the pressure loss of the fluid flowing from the inlet passage to the outlet passage in the vortex chamber depends on the length and flow velocity of the swirling flow (vortex flow) streamline from the inlet passage to the outlet passage. Therefore, as the flow velocity of the vortex flow of the fluid in the vortex chamber increases, the pressure loss occurring as the fluid flows from the inlet passage to the outlet passage increases, and the flow rate of the fluid flowing out of the outlet passage decreases. On the other hand, as the flow velocity of the vortex flow of the fluid in the vortex chamber decreases, the pressure loss occurring as the fluid flows from the inlet passage to the outlet passage decreases, and the flow rate of the fluid flowing out of the outlet passage increases. By utilizing these characteristics, the flow rate of the fluid flowing out of the outlet passage can be adjusted by using a drive unit to move the second end wall toward or away from the first end wall.

[0009] In the above-described vortex flow control valve, the second end wall may be configured as a diaphragm that is moved by a drive unit so as to approach and move away from the first end wall. If the second end wall is configured as such a diaphragm, the second end wall can be moved toward and away from the first end wall with a simple structure without providing any sliding or contact / separation parts.

[0010] In this case, the diaphragm may include, for example, a movable part that is moved by the driving part and an elastically deformable support part that is connected to the outer peripheral edge of the movable part and supports the movable part, or may include a movable part that is moved by the driving part and a flexible or bendable support part that is connected to the outer peripheral edge of the movable part and supports the movable part.

[0011] Preferably, the outlet flow passage is provided so that the axis of the outlet flow passage extends on the central axis of the vortex chamber.

[0012] Furthermore, in the above-mentioned vortex flow control valve, a protrusion protruding toward the diaphragm may be provided on the first end wall. By providing the protrusion, the protrusion interrupts the vortex flow, making it easier for the fluid to flow toward the outlet flow path, shortening the distance the fluid flows from the inlet flow path to the outlet flow path and reducing pressure loss, thereby achieving the effect of increasing the flow rate.

[0013] It is preferable that the first end wall and the second end wall have a circular or elliptical shape, in which case the vortex chamber has a cylindrical or elliptical cylindrical shape, so that the fluid flowing into the vortex chamber from the inlet passage flows along the peripheral side wall and is likely to form a vortex flow.

[0014] According to the present invention, a vortex is generated in the vortex chamber, and the flow velocity of the vortex increases or decreases by moving the second end wall toward or away from the first end wall to change the area through which the vortex can flow. By utilizing this characteristic, the pressure loss occurring as the fluid flows from the inlet channel to the outlet channel can be changed by moving the second end wall toward or away from the first end wall using a drive unit, thereby adjusting the flow rate of the fluid flowing out of the outlet channel. Therefore, the use of the vortex flow control valve of the present invention eliminates the need to provide a valve element and valve seat in an area that contacts the fluid to be controlled, thereby eliminating the contact area between the valve element and the valve seat. As a result, there is no need to reset flow rate control parameters due to wear on the valve element and valve seat, and particle contamination of the fluid can be suppressed.

[0015] FIG. 1 is a partially cutaway perspective view showing the overall configuration of a vortex type flow control valve according to the present invention, with a portion cut away so that the interior can be seen. FIG. 2 is a plan view of the vortex type flow control valve shown in FIG. 1, as seen from above. FIG. 3 is a side view of the vortex type flow control valve shown in FIG. 1, as seen from the side of FIG. 1. FIG. 4 is an explanatory diagram schematically showing a flow in a vortex chamber of the vortex type flow control valve shown in FIG. 1. FIG. 5 is an explanatory diagram schematically showing the operation of the vortex type flow control valve of the first embodiment. FIG. 6 is an explanatory diagram schematically showing the operation of the vortex type flow control valve of the first embodiment. FIG. 7 is an explanatory diagram schematically showing the operation of the vortex type flow control valve of the first embodiment. FIG. 8 is an explanatory diagram schematically showing the operation of the vortex type flow control valve of the second embodiment. FIG. 9 is an explanatory diagram schematically showing the operation of the vortex type flow control valve of the second embodiment. FIG. 11 is an explanatory diagram schematically showing the operation of a modified form of the vortex type flow control valve of the second embodiment. 8A and 8B are line graphs plotting measurement results of the relationship between the movement distance of the diaphragm in the direction from the home position toward the first end wall and the flow rate Q, obtained when the position of the inlet flow channel is changed in a numerical simulation using the vortex-type flow control valve shown in FIGS. 8A and 8B.

[0032] FIG. 8B is an explanatory diagram schematically showing the operation of a modified form of the vortex-type flow control valve of the second embodiment.

[0033] FIG. 8C is an explanatory diagram schematically showing the operation of a modified form of the vortex-type flow control valve of the second embodiment.

[0034] FIG. 8D is an explanatory diagram for explaining the configuration and dimensions of the vortex-type flow control valve used in the numerical simulation, showing the vortex-type flow control valve with the upper end wall (second end wall) removed, as viewed from above.

[0035] FIG. 8E is an explanatory diagram for explaining the configuration and dimensions of the vortex-type flow control valve used in the numerical simulation, showing the vortex-type flow control valve as viewed from the side.

[0036] FIG. 8F is a line graph plotting measurement results of the relationship between the movement distance of the diaphragm in the direction from the home position toward the first end wall and the flow rate Q, obtained when the position of the inlet flow channel is changed in a numerical simulation using the vortex-type flow control valve shown in FIGS. 8A and 8B is a line graph plotting the relationship between the position of the inlet flow channel and the flow rate difference ΔQ (amount of change in flow rate from the outlet flow channel) when the movement distance of the diaphragm is changed from 0.5 mm to 5.5 mm, obtained by a numerical simulation using the vortex type flow control valve shown in Figures 8A and 8B. Fig. 8B is an explanatory diagram schematically showing a vortex type flow control valve according to a third embodiment of the present invention. Fig. 8C is an explanatory diagram schematically showing a vortex type flow control valve according to a fourth embodiment of the present invention, showing a state in which the second end wall is located at the home position.FIG. 10 is an explanatory diagram schematically illustrating a vortex flow control valve according to a fourth embodiment of the present invention, showing a state in which the second end wall has moved toward the first end wall.

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the overall configuration of a vortex flow control valve 11 according to the present invention will be described with reference to FIGS.

[0017] The vortex flow control valve 11 includes a cylindrical peripheral wall 13 extending along a central axis, a first end wall 15 and a second end wall 17 provided at both ends of the peripheral wall 13 in the axial direction so as to face each other, an inlet flow path 19, and an outlet flow path 21, and the second end wall 17 can be moved toward and away from the first end wall 15. The first end wall 15 and the second end wall 17 are provided so as to close the ends of the peripheral wall 13 in the axial direction, and the space surrounded by the peripheral wall 13, the first end wall 15, and the second end wall 17 constitutes a cylindrical vortex chamber 27 extending along a vortex chamber central axis O. The vortex chamber central axis O coincides with the central axis of the peripheral wall 13. In this specification, the term "center" refers to the center of gravity of a cross section of a target portion, and the vortex chamber central axis refers to an axis perpendicular to the vortex chamber central axis O and passing through the center of gravity of each cross section of the vortex chamber 27. In the illustrated embodiment, the first end wall 15 and the second end wall 17 are circular and of the same size, the peripheral side wall 13 is cylindrical, and the vortex chamber central axis O extends so as to connect the center (center of gravity) of the first end wall 15 and the center (center of gravity) of the second end wall 17. However, the shapes of the first end wall 15 and the second end wall 17 are not limited to being circular, and can be any shape, such as an ellipse or a polygonal shape such as a triangle or a square, as long as a vortex flow can be generated in the vortex chamber 27. Furthermore, the first end wall 15 and the second end wall 17 are not limited to being flat, and may be formed, for example, by a curved surface.

[0018] The inlet passage 19 extends along an inlet passage central axis P1 perpendicular to the vortex chamber central axis O and opens to the peripheral side wall 13. The inlet passage central axis P1 extends so as to pass through the center of the cross section of the inlet passage 19. The outlet passage 21 extends from the vortex chamber 27 to the outside along an outlet passage central axis P2 parallel to the vortex chamber central axis O and opens to the first end wall 15 of the vortex chamber 27. The outlet passage central axis P2 extends so as to pass through the center of the cross section of the outlet passage 21. In the illustrated embodiment, both the inlet passage 19 and the outlet passage 21 are formed by circular pipes having circular cross sections. However, the cross sections of the inlet passage 19 and the outlet passage 21 are not limited to circular shapes and can also be polygonal shapes such as elliptical or rectangular. In the illustrated embodiment, the inlet passage 19 is formed by a straight circular pipe, but may have other shapes, such as a nozzle shape, as long as it can introduce fluid into the vortex chamber 27.

[0019] The inlet passage 19 is provided such that the inlet passage central axis P1 passes through an eccentric position away from the vortex chamber central axis O. Therefore, the fluid flowing in from the inlet passage 19 hits the circumferential side wall 13 in the vortex chamber 27 and flows along the circumferential side wall 13, generating a swirling flow. This vortex flow moves toward the outlet passage 21 and flows out from the outlet passage 21. To facilitate the generation of a swirling flow, the inlet passage 19 is preferably provided such that the fluid flowing into the vortex chamber 27 from the inlet passage 19 flows along the circumferential side wall 13. On the other hand, the outlet passage 21 can be provided at any position on the first end wall 15 as long as the fluid flowing into the vortex chamber 27 from the inlet passage 19 generates a vortex flow and then flows out from the outlet passage 21. In other words, the outlet passage 21 only needs to be provided such that the outlet passage central axis P2 extends through a position away from the inlet passage central axis P1 so that the fluid flowing into the vortex chamber 27 from the inlet passage 19 does not flow out from the outlet passage 21 as is.

[0020] In the illustrated embodiment, the inlet passage 19 extends in a tangential direction of the cylindrical circumferential side wall 13 and is connected to the circumferential side wall 13 so that the inlet passage central axis P1 is parallel to the tangent line, allowing the fluid to flow from the inlet passage 19 into the vortex chamber 27 in a direction substantially tangential to the circumferential side wall 13. The outlet passage 21 opens to the first end wall 15 and is provided so that the outlet passage central axis P2 passes through the center of the first end wall 15, i.e., so that the outlet passage central axis P2 extends on the vortex chamber central axis O. With this configuration, the fluid flowing in from the inlet passage 19 flows along the circumferential side wall 13 in the vortex chamber 27, generating a swirling flow, and then flows in a spiral pattern toward the outlet passage 21 as it gradually approaches the center.

[0021] At least a portion of the second end wall 17 is driven by a drive unit 25 to move within the vortex chamber 27 relative to the first end wall 15 along a movement axis extending parallel to the vortex chamber central axis O. The drive unit 25 can be any suitable mechanism, such as an electric actuator, as long as it can move the second end wall 17. The drive unit 25 can be driven by various drive methods, such as manual, air-driven, or electric. By using the drive unit 25 to move at least a portion of the second end wall 17 within the vortex chamber 27, the distance (i.e., the gap) between the first end wall 15 and the second end wall 17 changes. This changes the volume of the space through which the fluid flows, thereby increasing or decreasing the fluid flow area. Note that the drive unit 25 is omitted from FIG. 1 for clarity.

[0022] In the vortex flow control valve 11, the second end wall 17 can be configured as a diaphragm including a movable portion 17a moved by the drive portion 25 and a deformable support portion 17b extending between the end of the peripheral side wall 13 in the direction of the vortex chamber central axis O and the outer peripheral edge of the movable portion 17a, thereby supporting the movable portion. For example, in a first embodiment of the vortex flow control valve 11, the support portion 17b of the diaphragm constituting the second end wall 17 may be formed from an elastic material so that the support portion 17b is elastically deformable, allowing the movable portion 17a to move relative to the first end wall 15 (see FIGS. 5A to 5C ). In this case, to facilitate manufacturing of the diaphragm, it is preferable that the movable portion 17a be formed from the same type of elastic material as the support portion 17b. However, since the movable portion 17a can move if the support portion 17b is formed from an elastic material, the movable portion 17a may of course be formed from a different type of elastic or non-elastic material. Furthermore, as a second embodiment of the vortex flow control valve 11, the support portion 17b of the diaphragm constituting the second end wall 17 may be formed from a flexible material so that the support portion 17b is flexible or bendable, allowing the movable portion 17a to move relative to the first end wall 15. In this case, in the home position described below, the support portion 17b may be arranged so as to be curved in a convex shape that protrudes toward the first end wall 15 (see FIGS. 6A to 6C), or so as to be curved in a convex shape that protrudes in a direction away from the first end wall 15 (see FIGS. 7A to 7C).

[0023] Furthermore, in the illustrated embodiment, a push rod driven by an electric actuator is used as the driving unit 25. The push rod presses the movable portion 17 a of the diaphragm, deforming the support portion 17 b that supports the movable portion 17 a, allowing the movable portion 17 a of the diaphragm to move relative to the first end wall 15. However, the driving unit 25 is not limited to a push rod driven by an electric actuator, as long as the movable portion 17 a is capable of moving relative to the first end wall 15. For example, a push rod driven manually or by air drive may also be used as the driving unit 25. Furthermore, other mechanisms, such as a piston cylinder, may also be used as the driving unit 25, as long as they can press the movable portion 17 a of the diaphragm to deform the support portion 17 b.

[0024] Next, the operation of the vortex flow control valve 11 of the present invention will be described with reference to FIG. 4 and FIGS. 5A to 5C, taking the vortex flow control valve 11 of the first embodiment described above as an example.

[0025] As described above, the inlet passage 19 is disposed such that the inlet passage central axis P1 passes through an eccentric position away from the vortex chamber central axis O. Therefore, as shown in FIG. 4 , the fluid flowing in from the inlet passage 19 generates a swirling flow in the vortex chamber 27, swirling, and flows toward the outlet passage 21 before flowing out from the outlet passage 21. The diaphragm serving as the second end wall 17 is located in the home position shown in FIG. 5A when not pressed by the driving unit 25. From this state, as shown in FIG. 5B , when the second end wall 17 (the movable part 17a in the first embodiment) is pressed by the driving unit 25 and approaches the first end wall 15 on which the outlet passage 21 is provided, the distance between the first end wall 15 and the second end wall 17 becomes shorter, i.e., the gap becomes smaller. In the first embodiment shown in Figures 5A to 5C, pressing of the movable part 17a by the drive part 25 elastically deforms the support part 17b, shortening at least the distance between the movable part 17a and the first end wall 15. As a result, the area through which the vortex fluid generated in the vortex chamber 27 can pass is reduced, increasing the flow rate of the vortex fluid. The fluid that flows from the inlet passage 19 into the vortex chamber 27, forms a vortex, flows toward the outlet passage 21, and then flows out of the outlet passage 21 generates a pressure loss according to the flow distance and flow rate. Therefore, as described above, when the second end wall 17 approaches the first end wall 15, the flow rate increases compared to the state shown in Figure 5A, resulting in an increased pressure loss. As a result, the flow rate of the fluid flowing out of the outlet passage 21 decreases. When the second end wall 17 (the movable portion 17a in the first embodiment) is further pressed by the driving portion 25 from the state shown in Fig. 5B and approaches the first end wall 15 as shown in Fig. 5C, the flow velocity of the vortex flow increases further, causing a larger pressure loss. As a result, the flow rate of the fluid flowing out of the outlet flow passage 21 decreases further compared to the state shown in Fig. 5B.

[0026] In this way, in the vortex flow control valve 11, when the second end wall 17 is moved in a direction approaching the first end wall 15 and the gap between the first end wall 15 and the second end wall 17 is reduced, the pressure loss of the fluid flowing from the inlet passage 19 to the outlet passage 21 increases, and the flow rate of the fluid flowing out of the outlet passage 21 decreases. That is, by increasing the movement distance of the second end wall 17 from the home position in a direction approaching the first end wall 15 and reducing the area through which the vortex fluid generated in the vortex chamber 27 can pass, the pressure loss of the fluid flowing from the inlet passage 19 to the outlet passage 21 increases, and the flow rate of the fluid flowing out of the outlet passage 21 decreases. On the other hand, by shortening the movement distance of the second end wall 17 from the home position in a direction approaching the first end wall 15 and increasing the area through which the vortex fluid generated in the vortex chamber 27 can pass, the pressure loss of the fluid flowing from the inlet passage 19 to the outlet passage 21 decreases, and the flow rate of the fluid flowing out of the outlet passage 21 increases. Therefore, by moving or deforming the second end wall 17 relative to the first end wall 15 so as to change the gap between the first end wall 15 and the second end wall 17, the flow rate of the fluid flowing out of the outlet passage 21 can be adjusted without providing an abutting portion at the portion that comes into contact with the target fluid, and the valve can function as a flow control valve. Needless to say, this is also true for the vortex flow control valve 11 of the second embodiment shown in Figures 6A to 6C and 7A to 7C.

[0027] As can be seen from the above description, in the vortex flow control valve 11, the flow rate of the fluid flowing out of the outlet passage 21 can be changed by changing the gap between the first end wall 15 and the second end wall 17. Therefore, the present invention is not limited to the illustrated embodiment. That is, the vortex flow control valve 11 according to the present invention can be modified in a wide range of ways. For example, the second end wall 17 only needs to be able to move toward and away from the first end wall 15 when the movable portion 17a is pressed, causing the support portion 17b to deform, and the position of the movable portion 17a does not need to be the center of the second end wall 17. Furthermore, as in a third embodiment of the vortex flow control valve 11′ shown in FIG. 11 , a protrusion 29 may be provided on the first end wall 15, and the second end wall 17 may be moved toward and away from the protrusion 29 to change the gap between the top of the protrusion 29 and the second end wall 17. Furthermore, instead of deforming the second end wall 17 to move toward and away from the first end wall 15 as in the vortex flow control valve 11″ of the fourth embodiment shown in FIG. 12 , the second end wall 17′ may be made movable along the peripheral side wall 13, and the gap between the first end wall 15 and the second end wall 17′ may be changed by moving the second end wall 17′ along the peripheral side wall 13 from the home position shown in FIG. 12( a) to as shown in FIG. 12( b).

[0028] 11 and 12, components common to those of the vortex type flow control valve 11 of the embodiment shown in FIG. 1 are given the same reference numerals. Also, in the vortex type flow control valve 11' and vortex type flow control valve 11'', the second end wall 17 or the second end wall 17' moves toward and away from the first end wall 15, just like in the vortex type flow control valve 11 of the embodiment shown in FIG. 1, and the flow rate is also adjusted by changing the distance (gap) between the first end wall 15 and the second end wall 17. Therefore, detailed explanations of the configuration and operation will be omitted here.

[0029] Below, we will explain the relationship between the movement distance from the home position of the diaphragm that constitutes the second end wall 17, the position of the inlet passage 19 relative to the outlet passage 21, and the flow rate or amount of change in flow rate of the fluid, obtained by a numerical simulation (hereinafter simply referred to as simulation) of a vortex flow control valve having a configuration similar to that of the vortex flow control valve 11 of the embodiment shown in Fig. 1. In the following explanation, for ease of understanding, the same reference numerals as those used in the vortex flow control valve 11 will be used for each component of the vortex flow control valve used in the simulation.

[0030] In the following description, unless otherwise specified, the simulations are performed under the following conditions: vortex chamber 27 has a cylindrical shape with a diameter of 30 mm and a height of 7.5 mm, as shown in Figures 8A and 8B; inlet flow passage 19 has a straight cylindrical shape with a diameter of 3.5 mm and is connected to peripheral side wall 13 so that inlet flow passage central axis P1 passes from a position halfway along the height of vortex chamber 27 (i.e., the distance between first end wall 15 and second end wall 17) to a position 1.5 mm away from first end wall 15, i.e., a position 2.25 mm away from first end wall 15; outlet flow passage 21 has a circular cylindrical shape with a diameter of 3.5 mm and a length of 10 mm and extends along vortex chamber central axis O, and is connected to first end wall 15 so that outlet flow passage central axis P2 passes through the center of first end wall 15; and a circular region with a diameter of 14 mm concentric with second end wall 17 is pressed and moved by drive unit 25. The position of the inlet passage 19 relative to the outlet passage 21 is defined as the ratio (%) of the distance between the center of the vortex chamber 27 (i.e., the outlet passage central axis P2 of the outlet passage 21) and the inlet passage central axis P1 of the inlet passage 19 to the value obtained by dividing the difference between the diameter of the cylindrical vortex chamber 27 and the diameter of the circular pipe-shaped inlet passage 19 by 2. This is because the inlet passage 19 can only be located away from the center of the vortex chamber 27 up to a position where the inlet passage central axis P1 is away from the peripheral side wall 13 by the radius of the inlet passage 19.

[0031] First, the relationship between the movement distance (mm) of the diaphragm constituting the second end wall 17 from its home position and the flow rate Q of the fluid flowing out of the outlet flow passage 21 was confirmed. Here, the home position of the diaphragm is the position of the diaphragm when it is not being pressed by the driving unit 25. The simulation was performed for various positions of the inlet flow passage 19 relative to the outlet flow passage 21.

[0032] FIG. 9 is a line graph plotting the relationship between the movement distance (mm) of the diaphragm (second end wall 17) from the home position and the flow rate Q (L / min) of the fluid flowing out of the outlet flow path 21, obtained by simulation, for cases where the position of the inlet flow path 19 relative to the outlet flow path 21 is 0%, 25%, 50%, 62%, 75%, and 100%. In Figure 9, the symbol "●" indicates the relationship between the movement distance (mm) of the diaphragm (second end wall 17) from the home position and the flow rate Q (L / min) of the fluid flowing out of the outlet flow path 21 when the position of the inlet flow path 19 relative to the outlet flow path 21 is 0%, the symbol "▲" indicates the relationship when the position of the inlet flow path 19 relative to the outlet flow path 21 is 25%, the symbol "■" indicates the relationship when the position of the inlet flow path 19 relative to the outlet flow path 21 is 50%, the symbol "×" indicates the relationship when the position of the inlet flow path 19 relative to the outlet flow path 21 is 762%, the symbol "*" indicates the relationship when the position of the inlet flow path 19 relative to the outlet flow path 21 is 75%, and the symbol "◆" indicates the relationship when the position of the inlet flow path 19 relative to the outlet flow path 21 is 100%.

[0033] 9 , it was confirmed that, except when the inlet flow passage 19 is at a position of 0% with respect to the outlet flow passage 21, the flow rate Q of the fluid flowing out of the outlet flow passage 21 decreases as the distance the diaphragm (second end wall 17) moves from its home position toward the first end wall 15, i.e., as the distance between the first end wall 15 and the second end wall 17 decreases. This is presumably because, as the diaphragm moves longer from its home position, the area through which the fluid can pass becomes smaller, increasing the flow velocity. If a vortex occurs in the vortex chamber 27, the streamline from the inlet flow passage 19 to the outlet flow passage becomes longer, which increases the pressure loss associated with the increased flow velocity. Specifically, when the inlet flow passage central axis P1 does not intersect with the outlet flow passage central axis P2, the fluid flowing in from the inlet flow passage 19 collides with the circumferential side wall 13 in the vortex chamber 27, flows along the circumferential side wall 13, and forms a vortex toward the outlet flow passage 21. Therefore, the length of the streamline from the inlet flow passage 19 to the outlet flow passage 21 increases. Furthermore, when the diaphragm, which is the second end wall 17, moves from the home position toward the first end wall 15, the distance between the first end wall 15 and the second end wall 17 decreases, increasing the flow velocity of the vortex flow in the vortex chamber 27 and increasing the pressure loss. As a result of this increase in pressure loss, the flow rate of the fluid flowing out of the outlet flow passage 21 decreases.

[0034] 9 also shows that the flow rate Q of the fluid flowing out of the outlet flow passage 21 decreases as the inlet flow passage 19 is disposed so that the inlet flow passage central axis P1 passes through a position farther away from the outlet flow passage central axis P2. This is presumably because the vortex flow line from the inlet flow passage 19 to the outlet flow passage 21 becomes longer as the inlet flow passage central axis P1 is disposed at a position farther away from the outlet flow passage central axis P2.

[0035] In this way, when the inlet flow passage 19 is provided so that the inlet flow passage central axis P1 passes through a position away from the outlet flow passage central axis P2, the flow rate Q of the fluid flowing out of the outlet flow passage 21 changes depending on the movement distance of the second end wall 17 from the home position, and there is a correlation between the movement distance of the second end wall 17 from the home position and the flow rate Q. Therefore, by changing the movement distance of the second end wall 17 from the home position, the flow rate Q can be changed, and it is possible to adjust and control the flow rate Q.

[0036] Next, the influence of the position of the inlet passage 19 within the vortex chamber 27 was confirmed by simulation. Here, under the condition that the outlet passage 21 is connected to the first end wall 15 so as to extend from the center of the vortex chamber 27, the simulation was performed for cases where the position of the inlet passage 19 relative to the outlet passage 21 was 0%, 25%, 50%, 62%, 75%, and 100%.

[0037] FIG. 10 is a line graph plotting the relationship between the position of the inlet passage 19 relative to the outlet passage 21 and the flow rate difference ΔQ (L / min) obtained by changing the movement distance from the home position of the diaphragm, which is the second end wall 17, toward the first end wall 15 from 0.5 mm to 5.5 mm. From FIG. 10 , it was found that, under the condition that the outlet passage 21 is connected to the first end wall 15 so as to extend from the center of the vortex chamber 27, the flow rate difference ΔQ can be generated depending on the movement distance of the second end wall 17, regardless of the position of the inlet passage 19 relative to the outlet passage 21. Therefore, regardless of the position of the inlet passage 19 relative to the outlet passage 21, it is possible to adjust the flow rate of the fluid flowing out of the outlet passage 21 by moving the second end wall 17 of the vortex flow control valve 11. It was also found that the largest flow rate difference ΔQ was generated when the position of the inlet passage 19 relative to the outlet passage 21 was 50%, enabling flow rate adjustment over a wider range. Therefore, when a wide range of flow rate adjustment is required, it is preferable to provide the inlet flow path 19 so that the position of the inlet flow path 19 relative to the outlet flow path 21 is at a 50% position.

[0038] Although the vortex flow control valve according to the present invention has been described above with reference to the illustrated embodiment, the present invention is not limited to the illustrated embodiment. For example, while the illustrated embodiment employs a cylindrical vortex chamber 27, an elliptical or polygonal cylindrical vortex chamber may be employed as long as a vortex can be generated within the vortex chamber 27. Furthermore, since the flow rate Q can be changed by changing the gap by moving the second end wall 17 relative to the first end wall 15, a protrusion 29 may be provided on the first end wall 15, as in the third embodiment shown in FIG. 11 . Furthermore, as in the fourth embodiment shown in FIG. 12 , the distance between the first end wall 15 and the second end wall 17 may be changed by moving the second end wall 17′ along the peripheral side wall 13 toward the first end wall 15.

[0039] 11 Vortex flow type flow control valve 11' Vortex flow type flow control valve 11" Vortex flow type flow control valve 13 Peripheral side wall 15 First end wall 17 Second end wall 17a Movable part 17b Support part 17' Second end wall 19 Inlet flow path 21 Outlet flow path 25 Drive part 27 Vortex chamber

Claims

1. A vortex flow control valve comprising: a vortex chamber defined by a cylindrical peripheral side wall and first and second end walls provided at both ends of the peripheral side wall and facing each other, the vortex chamber extending along the central axis of the vortex chamber; an inlet flow path extending along the central axis of an inlet flow path and opening onto the peripheral side wall; and an outlet flow path extending along the central axis of an outlet flow path and opening onto the first end wall, wherein fluid flowing in from the inlet flow path forms a vortex within the vortex chamber and flows out from the outlet flow path, wherein the inlet flow path is arranged so that the central axis of the inlet flow path passes through a position away from the central axis of the vortex chamber and the central axis of the outlet flow path, and the second end wall is configured to be movable by a drive unit so as to approach and move away from the first end wall, and the flow rate of the fluid flowing out of the outlet flow path is adjusted according to the amount of movement of the second end wall relative to the first end wall.

2. The vortex type flow control valve according to claim 1, wherein the second end wall is constituted by a diaphragm that is moved by a drive portion so as to approach and move away from the first end wall.

3. A vortex-type flow control valve as described in claim 2, wherein the diaphragm includes a movable part that is moved by the driving part, and an elastically deformable support part that is connected to the outer peripheral edge of the movable part and supports the movable part.

4. A vortex-type flow control valve as described in claim 2, wherein the diaphragm includes a movable portion that is moved by the driving portion, and a flexible or bendable support portion that is connected to the outer peripheral edge of the movable portion and supports the movable portion.

5. A vortex flow control valve as set forth in claim 1, wherein the outlet passage is provided so that the central axis of the outlet passage extends on the central axis of the vortex chamber.

6. The vortex type flow control valve according to claim 1, wherein said first end wall is provided with a protrusion that protrudes toward said diaphragm.

7. A vortex flow control valve according to any one of claims 1 to 6, wherein the first end wall and the second end wall are circular or elliptical.