valve

Abstract

The present invention provides a valve suitable for use as a fluid-operated valve for high-pressure fluids. [Solution] The valve 100 includes a valve body 10 having an inlet passage 16, an outlet passage 18 and a valve chamber 14, a valve stem 20 having a valve element 22 at one end that can contact and separate from a valve seat 12 provided in the valve chamber, and an actuator 30 that moves the valve stem along the axial direction D1. The actuator 30 includes a housing 32 that forms an internal space, a piston 34 housed in the housing so as to be axially movable and which divides the internal space into a first space S1 and a second space S2, connected to the other end of the valve stem, a plurality of coil springs 36 arranged in the first space that press the piston in the axial direction, a plurality of stays 40 that pass through the plurality of coil springs and are fixed to the piston or housing and extend in the axial direction, and a working fluid inlet 38 into which working fluid can be introduced into the second space.

Description

Technical Field

[0001] The present invention relates to a valve, and particularly to a valve that can be suitably used for controlling the flow of high-pressure fluid.

Background Art

[0002] Conventionally, as a valve for controlling the flow of fluid, there is known one that controls the opening / closing or the opening degree of the valve by using an actuator to which an operating fluid such as air or oil is supplied. Such a valve is called a fluid-operated valve, and for example, an AOV (Air Operated Valve) using air as the operating fluid is widely and commonly used.

[0003] In a fluid-operated valve, the operating fluid is used to move a piston in a cylinder in an actuator. A valve body is connected to the piston via a valve rod or the like, and by controlling the operating fluid pressure, the valve body can be opened and closed with respect to the valve seat (for example, Patent Document 1).

[0004] Among such types of valves, there are those that apply a biasing force to the piston in advance using an elastic member such as a coil spring. In a reverse-acting type fluid-operated valve, a biasing force is applied in the closing direction by the elastic member, and the valve body can be opened against the biasing force by supplying the operating fluid pressure (normally closed type). Also, in a direct-acting type fluid-operated valve, a biasing force is applied in the opening direction by the elastic member, and the valve body can be closed against the biasing force by supplying the operating fluid pressure (normally open type).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] When using fluid-operated valves as described above for high-pressure or ultra-high-pressure control fluids (e.g., 10 MPa to 100 MPa), the valve body is subjected to high pressure from the control fluid, requiring the actuator to apply a relatively strong biasing force using a coil spring. Furthermore, to accommodate large flow rates, the actuator requires the piston and valve stem to move over relatively long distances.

[0007] When meeting the demands of such high-pressure applications using a single coil spring, a relatively large spring is required to accommodate the required thrust and stroke. However, such large coil springs are not readily available, leading to increased manufacturing costs. Furthermore, they present challenges in achieving compact valve designs.

[0008] In contrast, a fluid-operated valve using an actuator configured to apply biasing force using multiple coil springs is disclosed, for example, in Patent Document 2. Using multiple coil springs makes it easier to achieve miniaturization compared to using a single coil spring, and also makes it relatively easy to obtain the coil springs.

[0009] However, the inventors of this invention have found that simply adding multiple coil springs to an actuator that was previously constructed using a single coil spring can degrade its performance as a valve.

[0010] This invention has been made in view of the above problems, and its main objective is to provide a valve that can be used as a fluid-operated valve for high pressure applications, and that can be miniaturized and accommodate large flow rates while suppressing cost increases. [Means for solving the problem]

[0011] A valve according to an embodiment of the present invention comprises a valve body having an inlet passage, an outlet passage, and a valve chamber communicating with the inlet passage and the outlet passage; a valve stem having a valve element at one end that can contact and separate from a valve seat formed in the valve chamber; and an actuator that can move the valve stem in the axial direction. The actuator includes a housing that forms a cylindrical internal space; a piston housed axially movable within the housing and connected to the other end of the valve stem, which divides the internal space into a first space and a second space; a plurality of coil springs arranged in the first space and pressing the piston in the axial direction; a plurality of stays that each penetrate the axial center of each of the plurality of coil springs, with one end of each stay fixed to either the piston or the housing and extending in the axial direction; and a working fluid inlet that communicates with the second space and allows the introduction of working fluid for moving the piston in opposition to the pressing by the coil springs.

[0012] In one embodiment, the plurality of coil springs are arranged adjacent to each other and symmetrically with respect to the central axis of the housing, and each of the plurality of stays is positioned such that one end is fixed to the housing and the other end does not come into contact with the piston.

[0013] In one embodiment, the housing includes a cylindrical member that forms the circumferential surface of the cylindrical internal space and a lid member that covers the end face of the cylindrical internal space opposite to the valve body, The aforementioned multiple stays are fixed to the lid member. [Effects of the Invention]

[0014] The valve according to the embodiment of the present invention can be suitably operated as a high-pressure fluid-operated valve while suppressing cost increases. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing the configuration of a valve according to an embodiment of the present invention. [Figure 2]It is a plan view showing the inner surface side of the lid member of the actuator included in the valve according to the embodiment of the present invention. [Figure 3] It is a view showing a stay provided in an actuator included in a valve according to an embodiment of the present invention, (a) is a plan view, and (b) is a side view.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0017] FIG. 1 shows a valve 100 according to an embodiment of the present invention. The valve 100 includes a valve body 10 having a flow path through which a control fluid flows, a valve rod 20 having a valve body 22 at an end that can contact and separate from a valve seat 12 formed in the flow path of the valve body 10, and an actuator 30 for moving the valve rod 20 along the axial direction D1.

[0018] For convenience, in this specification, in accordance with the drawings, the side where the valve body 10 in the valve 100 is arranged is described as the lower side, and the side where the actuator 30 is arranged is described as the upper side. However, it is needless to say that it may be different from the actual vertical direction depending on the mounting posture of the valve 100.

[0019] The valve body 10 is constituted by, for example, a metal block made of stainless steel (for example, SUS316L), and has a valve chamber 14 in which a valve seat 12 is formed, an inlet flow path 16 and an outlet flow path 18 communicating with the valve chamber 14 inside. In the valve body 10, the control fluid flows in the order of the inlet flow path 16, the valve chamber 14, and the outlet flow path 18.

[0020] When the valve body 22 provided at the tip of the valve rod 20 abuts against the valve seat 12, the valve 100 is in the closed state, and the flow of the control fluid from the inlet passage 16 to the outlet passage 18 is blocked. On the other hand, when the valve body 22 and the valve seat 12 are separated from each other, the valve 100 is in the open state, and the control fluid flows from the inlet passage 16 to the outlet passage 18 at a flow rate corresponding to the separation distance.

[0021] The operation of the valve rod 20, that is, the movement of the valve rod 20 in the axial direction D1, is controlled by the actuator 30. In the present embodiment 30, the actuator 30 is fixed to the upper side of the valve body 10 with a space therebetween by two support members 24. A limit switch that operates by the movement of the valve rod 20 may be arranged between the actuator 30 and the valve body 10 so that the opening and closing operations of the valve 100 can be mechanically detected.

[0022] The actuator 30 includes a housing 32 that forms a cylindrical internal space, a piston 34 that is accommodated inside the housing 32 and is movable along the axial direction D1, and a plurality of coil springs 36 that press the piston 34 in the axial direction D1.

[0023] In the present embodiment, the housing 32 is composed of a first cylindrical member 32a and a second cylindrical member 32b that form the circumferential surface of the side surface, and a lid member (or actuator cap) 32c that covers the upper open surface of the first cylindrical member 32a (the end surface on the opposite side of the valve body 10 of the cylindrical internal space). The first cylindrical member 32a, the second cylindrical member 32b, and the lid member 32c are formed of, for example, an aluminum alloy.

[0024] The first cylindrical member 32a and the second cylindrical member 32b are connected by a connecting member 32d. The second cylindrical member 32b is a bottomed cylindrical member disposed below the first cylindrical member 32a, that is, on the side of the valve body 10, and the piston 34 is accommodated therein to form a cylinder. An annular piston packing made of, for example, rubber for improving airtightness may be arranged on the outer peripheral surface of the piston 34 (that is, the surface facing the inner peripheral surface of the second cylindrical member 32b).

[0025] A through-hole is formed in the center of the bottom of the second cylindrical member 32b, and a rod 26 connected to the piston 34 passes through this through-hole. An annular rod packing, for example made of rubber, may be placed on the inner circumferential surface of the through-hole in the center of the bottom of the second cylindrical member 32b (i.e., the surface facing the outer circumferential surface of the rod 26) to improve airtightness.

[0026] The rod 26 and the valve stem 20 are connected so that they can move together as a single unit, and are fixed to each other by screwing them together using a screw mechanism. By configuring the rod 26 and the valve stem 20 to be detachable, the components on the valve body 10 side, including the valve stem 20, and the components on the actuator 30 side, including the rod 26, can be separated relatively easily. This improves the ease and precision of assembly, and also allows for easy replacement of the actuator 30 while the valve body 10 remains incorporated into the fluid system, in the event of a malfunction in the actuator 30.

[0027] In this embodiment, the first cylindrical member 32a and the second cylindrical member 32b are divided to facilitate assembly, but the first cylindrical member 32a and the second cylindrical member 32b may be integrally formed as one bottomed cylindrical member. Alternatively, the first cylindrical member 32a and the lid member 32c may be integrally formed.

[0028] The piston 34 is disc-shaped and is positioned to slide vertically along the axial direction D1 along the inner circumferential surface of the second cylindrical member 32b, and to be axially rotatable. The other end of the valve stem 20, that is, the end opposite to the tip on which the valve body 22 is provided, is fixed to the piston 34. This allows the valve stem 20 and the valve body 22 to move along the axial direction D1 in conjunction with the movement of the piston 34.

[0029] In this embodiment, the valve 100 shown in Figure 1 is a reverse-acting fluid-operated valve, and the internal space of the housing 32 is divided by a piston 34 into an upper first space S1 and a lower second space S2. In this embodiment, a plurality of coil springs 36 are arranged in the upper first space S1, that is, the space sandwiched between the lid member 32c and the piston 34.

[0030] Multiple coil springs 36 have a natural length that allows them to contact the lid member 32c and the piston 34 and be compressed between them. In this configuration, the piston 34 is constantly pressed downward in the axial direction by the biasing force of the coil springs 36.

[0031] On the other hand, the lower second space S2 is provided with a working fluid inlet 38 for introducing working fluid (compressed air in this case), and by supplying working fluid pressure, it is possible to push the piston 34 upward against the biasing force of the coil spring 36.

[0032] In this way, by using multiple coil springs 36, it is possible to control the flow of high-pressure controlled fluid effectively while preventing an increase in size and maintaining ease of availability, compared to using a single coil spring. The coil springs 36 are formed from materials such as oil-tempered wire (SWOSC).

[0033] However, it was found that when multiple coil springs 36 are mounted on a conventional single-coil spring actuator, the multiple coil springs 36 may tilt diagonally along the circumferential direction when the actuator is operated. This is thought to be because, when the actuator 30 is assembled, especially during the initial opening and closing of the valve, a small diagonal force acts from the coil springs 36 in a direction that rotates the piston 34, causing each spring to tilt from the axial direction.

[0034] The force acting to rotate the piston 34 is affected by the assembly condition and individual differences in the springs, and even if the machining and assembly precision of the parts is improved, it is practically difficult to completely prevent it. Furthermore, once the multiple coil springs 36 become tilted in this way, the biasing force in the axial downward direction decreases, and the piston 34 is no longer given the thrust it was designed to provide. For this reason, especially when used as a high-pressure valve, leaks may occur, for example, when the valve is closed.

[0035] Therefore, in the valve 100 of this embodiment, a stay 40 is provided for each coil spring 36 to prevent it from tipping over. Each stay 40 extends along the axial direction D1, passing through the axial center inside the corresponding coil spring 36, and is configured to support the coil spring 36 when a force that causes it to tip over is applied, thereby maintaining its posture.

[0036] Each stay 40 is fixed at one end to the piston 34 or the housing 32 (more specifically, the inner surface of the lid member 32c) in order to function as a support member. In this embodiment, the upper end of each stay 40 is fixed to the lid member 32c, while the lower end is provided so as not to come into contact with the upper surface of the piston 34.

[0037] Figure 2 shows the back surface (inner surface) of the lid member 32c. Figure 3(a) is a top view of the stay 40, and Figure 3(b) is a side view of the stay 40.

[0038] As shown in Figure 2, in this embodiment, the inner surface of the lid member 32c is provided with a cylindrical projection 42 having an outer diameter that matches the inner diameter of the first cylindrical member 32a. Six screw holes 44 are provided evenly along the circumferential direction in the region of this projection 42 for fixing six stays 40 (see Figures 3(a) and (b)). The stays 40 can be easily fixed to the lid member 32c by screwing screws 48 provided on the upper end of the stays 40 into the screw holes 44.

[0039] Furthermore, six cylindrical recesses 46 are formed evenly along the circumferential direction, concentric with the screw holes 44, on the protruding portion 42 of the lid member 32c. These recesses have a diameter equal to that of the upper end of each coil spring 36 and are capable of accommodating them. This restricts the movement of the upper end of the coil spring 36 within the recesses 46 of the lid member 32c, and prevents the coil spring from tipping over by the stay 40 extending axially D1 through the inside of the coil spring 36 from the lid member 32c. As shown in Figure 1, similar recesses may also be formed on the upper surface of the piston 34 to restrict the movement of the lower end of the coil spring 36.

[0040] In this way, by arranging multiple coil springs 36 adjacent to each other and symmetrically with respect to the central axis of the housing 32 or piston 34, and inserting a stay 40 into each coil spring 36, even when the actuator 30 is operated, the force acting from the coil springs 36 in the direction of axial rotation of the piston 34 is suppressed, preventing the coil springs 36 from tilting, and allowing the coil springs 36 to continuously apply a sufficient biasing force along the axial direction D1 to the piston 34. The number of coil springs 36 and stays 40 can be set to, for example, 3 to 12. The more coil springs 36 and stays 40 there are, the easier it is to apply a uniform biasing force to the piston 34, but if the number is too large, the manufacturing cost will increase, so it is preferable to use an appropriate number as described above.

[0041] Although a valve according to an embodiment of the present invention has been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention. For example, although an embodiment in which the stay 40 is fixed to the cover member 32c has been described above, the stay 40 may also be fixed to the piston 34.

[0042] Furthermore, although the above describes a reverse-acting (normally closed) valve in which a coil spring 36 is positioned in the first space S1 above the piston 34 and working fluid is introduced into the second space S2 below, the present invention can also be applied to a forward-acting (normally open) fluid-operated valve in which working fluid is introduced into the first space S1 above and multiple coil springs are provided in the second space S2 below. In this case, by providing a stay that penetrates the coil spring 36 in the second space S2 to prevent the spring from tilting, the decrease in the biasing force in the axial direction upward by the coil spring 36 after the opening and closing operation can be suppressed. [Industrial applicability]

[0043] A valve according to an embodiment of the present invention is suitably used, for example, to control the flow of a high-pressure fluid through a pipe. [Explanation of symbols]

[0044] 10 Valve Body 12 valve seats 14 valve chambers 16 Inlet channel 18 Outlet channel 20 valve stems 22 Valve body 24 Support members 26 rods 30 Actuators 32 cabinets 32a First cylindrical member 32b Second cylindrical member 32c Lid component 32d Connecting member 34 pistons 36 Coil springs 38 Working fluid inlet 40 Stay 100 valves

Claims

1. A valve body having an inlet passage, an outlet passage, and a valve chamber communicating with the inlet passage and the outlet passage, A valve stem having a valve body at one end that can contact and separate from a valve seat formed in the valve chamber, The valve stem is provided with an actuator that can move in the axial direction. A valve equipped with, The actuator is A housing that forms a cylindrical internal space, A piston is housed within the housing so as to be movable in the axial direction, connected to the other end of the valve stem, and divides the internal space into a first space and a second space. A plurality of coil springs arranged in the first space and pressing the piston in the axial direction, A plurality of stays that each penetrate the axial center of the plurality of coil springs, the plurality of stays having one end fixed to either the piston or the housing and extending in the axial direction, A working fluid inlet that communicates with the second space and allows the introduction of working fluid for moving the piston in opposition to the pressure applied by the coil spring, Valves, including

2. The valve according to claim 1, wherein the plurality of coil springs are adjacent to each other and arranged symmetrically with respect to the central axis of the housing, and each of the plurality of stays is positioned such that one end is fixed to the housing and the other end does not come into contact with the piston.

3. The housing includes a cylindrical member that forms the circumferential surface of the cylindrical internal space and a cover member that covers the end face of the cylindrical internal space opposite to the valve body. The valve according to claim 1 or 2, wherein the plurality of stays are fixed to the cover member.

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