valve

Abstract

The present invention provides a valve suitable for use as a fluid-operated valve for high-pressure fluids. [Solution] The valve 100 comprises 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 its end that can contact and separate from a valve seat 12 formed in the valve chamber; and an actuator 30 that can move the valve stem in the axial direction D1. The actuator 30 comprises a housing 32; a piston 34 housed inside the housing so as to be movable along the axial direction, connected to the valve stem and dividing the internal space into a first space S1 and a second space S2; a plurality of coil springs 36 arranged in the first space and biasing the piston in the axial direction; a working fluid inlet 38 for introducing working fluid into the second space; and a limiting member 40 fixed to the housing and engageable with the piston, which prevents the piston from rotating around its axis.

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 has been known a fluid-operated valve configured to perform opening / closing operation and opening degree control of the valve using an actuator driven by a working fluid. As fluid-operated valves, AOV (Air Operated Valve) that uses compressed air as the working fluid is widely and generally used.

[0003] In a fluid-operated valve, a working fluid such as air or oil is used to move a piston in a cylinder included in an actuator. A valve body is connected to the piston via a valve stem or the like, and the valve body can be opened and closed relative to a valve seat by controlling the working fluid pressure (for example, Patent Document 1).

[0004] Some valves of this type apply an urging force to the piston in advance by using an elastic member such as a coil spring. In a reverse-acting fluid-operated valve, an urging force is applied in the closing direction by the elastic member, and the valve can be opened against the urging force by supply of working fluid pressure (normally closed type). Further, in a forward-acting fluid-operated valve, an urging force is applied in the opening direction by the elastic member, and the valve can be closed against the urging force by supply of working fluid pressure (normally open type).

Prior Art Literature

Patent Literature

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[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 using a single coil spring to handle high-pressure, high-flow applications, a relatively large spring is required to accommodate the necessary 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, fluid-operated valves equipped with actuators configured to apply biasing force using multiple coil springs are disclosed, for example, in Patent Documents 2 and 3. Using multiple coil springs makes it easier to achieve miniaturization compared to using a single coil spring, and also reduces costs because coil springs can be obtained relatively easily.

[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, especially for high-pressure applications.

[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 its 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 comprises a housing that forms a cylindrical internal space; a piston housed inside the housing so as to be movable along the axial direction, connected to the valve stem, and dividing the internal space into a first space and a second space; a plurality of coil springs arranged in the first space that bias the piston along the axial direction; a working fluid inlet that communicates with the second space and allows the introduction of working fluid for moving the piston against the biasing force of the coil springs; and a limiting member fixed to the housing and engaged with the piston, configured to prevent rotation of the piston about its axis.

[0012] In one embodiment, the limiting member is an annular flange fixed to the housing and having an inner hole, and the piston has a cylindrical body portion that is slidable against the inner circumferential surface of the housing and an engaging portion fixed to the body portion, and the engaging portion of the piston is inserted into the inner hole of the flange, and at least one rotation-restricting surface formed on the inner circumferential surface of the flange and at least one rotation-restricting surface formed on the outer circumferential surface of the engaging portion of the piston engage to prevent the rotation of the piston.

[0013] In one embodiment, the upper surface shape of the inner hole of the flange and the upper surface shape of the engagement portion of the piston are substantially the same.

[0014] In one embodiment, the engagement portion of the piston has a smaller diameter than the main body of the piston.

[0015] In one embodiment, the rotation preventing surface of the flange includes two opposing flat surfaces, and the rotation preventing surface of the piston includes two opposing flat surfaces.

[0016] In one embodiment, the housing includes a bottomed cylindrical cylinder member that accommodates the piston and has a central hole through which the valve stem passes, a cylindrical member that forms a peripheral surface of the columnar internal space, and a lid member that covers an end surface of the cylindrical member, and both ends of the plurality of coil springs are accommodated in a plurality of accommodation recesses formed in the piston and a plurality of accommodation recesses formed in the lid member.

[0017] In one embodiment, the plurality of coil springs are adjacent to each other and arranged symmetrically with respect to the central axis of the housing. Effects of the Invention

[0018] The valve according to an embodiment of the present invention can suitably operate as a high-pressure fluid-operated valve while suppressing an increase in cost. Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view showing the configuration of the valve according to the embodiment of the present invention. [Figure 2] It is an enlarged cross-sectional view showing the actuator of the valve device shown in Fig. 1. [Figure 3] It is a plan view showing the engagement state of the flange and the piston included in the valve according to the embodiment of the present invention. Mode for Carrying Out the Invention

[0020] 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.

[0021] Figure 1 shows a valve 100 according to an embodiment of the present invention. The valve 100 includes a valve body 10 having a flow passage through which a control fluid flows, a valve stem 20 having at an end thereof a valve element 22 capable of coming into contact with and separating from a valve seat 12 formed in the flow passage of the valve body 10, and an actuator 30 for moving the valve stem 20 along the axial direction D1. Figure 2 shows the actuator 30 in an enlarged manner.

[0022] For convenience, in the present specification, with reference to the drawings, the description will be given with the side of the valve 100 where the valve body 10 is disposed being the lower side, and the side where the actuator 30 is disposed being the upper side. Needless to say, depending on the mounting orientation of the valve 100, this may differ from the actual vertical direction.

[0023] The valve body 10 is formed of, for example, a metal block made of stainless steel (e.g., SUS316L), and has therein a valve chamber 14 in which the valve seat 12 is formed, and an inlet flow passage 16 and an outlet flow passage 18 communicating with the valve chamber 14. In the valve body 10, the control fluid flows through the inlet flow passage 16, the valve chamber 14, and the outlet flow passage 18 in this order.

[0024] When the valve element 22 provided at the tip end portion of the valve stem 20 is in contact with the valve seat 12, the valve 100 is in a closed state, and the flow of the control fluid from the inlet flow passage 16 to the outlet flow passage 18 is blocked. On the other hand, when the valve element 22 is separated from the valve seat 12, the valve 100 is in an open state, and the control fluid flows from the inlet flow passage 16 to the outlet flow passage 18 at a flow rate corresponding to the separation distance.

[0025] The operation of the valve stem 20, that is, the movement of the valve stem 20 in the axial direction D1, is controlled by the actuator 30. In the present embodiment, the actuator 30 is fixed to the upper side of the valve body 10 with a space therebetween by a plurality of support members 24. A limit switch that operates in accordance with the movement of the valve stem 20 may be disposed between the actuator 30 and the valve body 10, so that the opening and closing operation of the valve 100 can be mechanically detected.

[0026] The actuator 30 comprises a housing 32 that forms a generally cylindrical internal space, a piston 34 housed inside the housing 32 and movable along the axial direction D1, and a plurality of coil springs 36 that press the piston 34 in the axial direction D1.

[0027] Furthermore, the actuator 30 is equipped with a flange 40 as a limiting member to prevent rotation of the piston 34 around its axis. The flange 40 is positioned close to the piston 34 and is configured to contact and engage with the piston 34. The piston 34 is made of, for example, an aluminum alloy, and the flange 40 is made of, for example, stainless steel. Details of the piston 34 and flange 40 will be described later.

[0028] In this embodiment, the housing 32 is composed of a bottomed cylindrical cylinder member 32c in which a piston 34 is housed inside, a cylindrical member 32b that forms the circumferential surface of the side, and a lid member (or actuator cap) 32a that covers the upper open surface of the cylindrical member 32b. The lid member 32a, the cylindrical member 32b, and the cylinder member 32c are formed from, for example, an aluminum alloy.

[0029] The cylindrical member 32b is provided in a cylindrical shape above the piston 34, surrounding the space where the multiple coil springs 36 are arranged. In this embodiment, the upper end of the cylindrical member 32b is fixed by engaging with an annular groove provided on the lower surface of the lid member 32a, and the lower end of the cylindrical member 32b is fixed by engaging with an annular groove 40G (see Figure 3) provided on the upper surface of the flange 40.

[0030] In this embodiment, the lid member 32a and the cylinder member 32c are connected by multiple rod-shaped fixing members (not shown) that pass through multiple through holes 42 (see Figure 3) provided on the periphery of the flange 40. Some of the through holes 42 provided on the periphery of the flange 40 may be used for screw fastening between the flange 40 and the cylinder member 32c.

[0031] A through-hole is formed in the center of the bottom of the cylinder member 32c, and a rod 26 connected to the valve stem 20 passes through this through-hole. The rod 26 is fixed to the piston 34. An annular rod packing, for example made of rubber, may be placed on the inner circumferential surface of the through-hole in the cylinder member 32c (i.e., the surface facing the outer circumferential surface of the rod 26) to improve airtightness.

[0032] 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, can be separated from the actuator 30 relatively easily. This improves the ease and precision of assembly, and in the event of a malfunction in the actuator 30, the actuator 30 can be replaced relatively easily while the valve body 10 remains incorporated into the fluid system.

[0033] In this embodiment, a second rod 28 is provided on the upper part of the piston 34, connected to the rod 26 through the central hole of the piston 34. The rod 26 and the second rod 28 are fixed to each other via a connecting member so as to sandwich the piston 34, and are able to move up and down together with the piston 34. However, the rod 26 and the second rod 28 do not need to be completely fixed to the piston 34, and in order to avoid the need for high assembly precision, the piston 34 may be configured to move slightly around the central axes of the rod 26 and the second rod 28.

[0034] Furthermore, the second rod 28 extends outward through the lid member 32a, and a head flange 29 is fixed to its tip. Above the lid member 32a, a handle 39 is provided around the second rod 28 below the head flange 29, which is engaged with the lid member 32a by a threaded portion 39S. The handle 39 can be moved up and down relative to the lid member 32a by manually rotating it.

[0035] In this configuration, the second rod 28 can be moved upward by rotating the handle 39 and pushing the head flange 29 upward along the axial direction D1. Therefore, even if operating air is not supplied due to trouble or other reasons, the valve can be forcibly opened. A mechanism for manually forcibly opening a fluid-operated valve in this manner is disclosed, for example, in Patent Document 3.

[0036] In this embodiment, in order to simplify the shape of each component and facilitate assembly and disassembly, the lid member 32a and the cylinder member 32c are fixed together with the flange 40 and the cylindrical member 32b interposed therebetween. However, other configurations can also be adopted. For example, the lid member 32a and the cylindrical member 32b may be formed integrally. Also, depending on the engagement manner between the flange 40 and the piston 34, the flange 40 may also be formed integrally with the lid member 32a and the cylindrical member 32b.

[0037] The piston 34 is disc-shaped and can slide vertically along the axial direction D1 along the inner circumferential surface of the cylinder member 32c. Furthermore, since the piston 34 is connected to the valve stem 20 via the rod 26 so as to be integrally movable with it, the valve stem 20 and valve body 22 can be moved along the axial direction D1 in conjunction with the movement of the piston 34. A groove provided on the outer circumferential surface of the piston 34 (i.e., the surface facing the inner circumferential surface of the cylinder member 32c) may be fitted with, for example, a rubber annular piston packing to improve airtightness.

[0038] Here, the valve 100 is a reverse-acting fluid-operated valve, and the internal space of the housing 32 is divided into a first space S1 and a second space S2 by the piston 34. 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 32a and the piston 34.

[0039] Multiple coil springs 36 have a natural length that allows them to contact the lid member 32a 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. In this embodiment, as can be seen from the spring housing recess 34R on the upper surface of the piston shown in Figure 3, six coil springs 36 are arranged adjacent to each other, evenly spaced along the circumferential direction around the axis (i.e., at 60° intervals).

[0040] On the other hand, the lower second space S2 is provided with a working fluid inlet 38 for introducing working fluid, and by supplying working fluid pressure, it is possible to push the piston 34 upward along the axial direction D1 against the biasing force of the coil spring 36. In this embodiment, compressed air is used as the working fluid, and it is preferable that the second space S2 has high airtightness.

[0041] In this way, by using multiple coil springs 36, it is possible to control the flow of high-pressure controlled fluids effectively while preventing an increase in size and maintaining ease of availability, compared to using a single coil spring. It can also handle the control of large-flow fluids. The coil springs 36 are formed from materials such as oil-tempered wire (SWOSC).

[0042] 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 around its axis, causing each spring to tilt from the axial direction.

[0043] Once the coil spring 36 becomes tilted, the biasing force provided by the coil spring 36 shifts from the vertical direction (axial direction D1), causing subsequent movements to rotate the piston 34 more. For this reason, the rotation of the piston 34 and the tilt of the spring may increase with each opening and closing of the valve.

[0044] 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. When multiple coil springs 36 tilt in this way, the biasing force in the axial direction decreases according to the degree of tilt, and the piston 34 is no longer given the thrust as designed. For this reason, especially when used as a high-pressure valve, leakage may occur when the valve is closed, for example, and performance may deteriorate.

[0045] Therefore, in the valve 100 of this embodiment, a flange 40 fixed to the housing 32 is provided to engage with the piston 34 as a limiting member to prevent rotation of the piston 34 around its axis. As a result, even when the valve is operating, the piston 34 will not rotate due to the force received from the multiple coil springs 36, and the tilting of the multiple coil springs 36 will not cause a decrease in performance.

[0046] Furthermore, Patent Document 4 discloses a configuration in which a guide mechanism is provided at the tip of the piston to prevent the piston from rotating. However, this guide mechanism is merely provided to prevent the piston from rotating along with the upper end of a rod that passes through the center of the piston when the initial valve body position is adjusted by rotating the rod using a tool. In other words, the guide mechanism described in Patent Document 4 is not provided for the purpose of preventing the tilting of the multiple coil springs arranged around the axis.

[0047] The detailed configuration of the piston 34 and flange 40 will be described below with reference to Figures 2 and 3. Figure 2 is an enlarged cross-sectional view of the actuator 30 shown in Figure 1, and Figure 3 is a plan view showing the flange 40 and the piston 34 engaged therewith.

[0048] As shown in Figure 2, in this embodiment, the piston 34 includes a disc-shaped main body portion 34a that slides against the inner circumferential surface of the cylinder member 32c, and an engaging portion 34b provided on the upper part of the main body portion 34a. The main body portion 34a is formed in a cylindrical shape having an outer diameter equivalent to the inner diameter of the cylinder member 32c. On the other hand, the engaging portion 34b is typically formed with a smaller diameter than the main body portion 34a.

[0049] Depending on the engagement configuration between the flange 40 and the piston 34, the engagement portion 34b of the piston 34 does not necessarily need to be smaller in diameter than the main body portion 34a; it may be the same diameter or even larger. If the engagement portion 34b is larger in diameter, the torque will increase, which can reduce the resistance force from the flange 40 required to prevent rotation. However, this tends to increase the overall size of the device and the sliding resistance tends to increase. Therefore, in order to allow the piston 34 to slide smoothly in a compact configuration, it is preferable that the engagement portion 34b is smaller in diameter than the main body portion 34a, as described in this embodiment.

[0050] As shown in Figure 3, the engaging portion 34b of the piston 34 is generally cylindrical, but has a pair of opposing flat surfaces 34F on its side, formed by cutting off two sides of the peripheral edge of the cylinder along the axial direction. The flange 40 is generally donut-shaped, but has a pair of opposing flat surfaces 44F in a part of the inner hole 44.

[0051] In the illustrated embodiment, the upper surface shape of the engaging portion 34b of the piston 34 and the upper surface shape of the inner hole 44 of the flange 40 are substantially the same (here, this means that they are similar in shape, even if they differ slightly in size, as long as the rotation-preventing function is not impaired), and the engaging portion 34b is inserted into the inner hole 44 so that the respective planes 34F and 44F face each other. In this configuration, even when a force that rotates the piston 34 around its axis is applied by the coil spring 36, the rotation of the piston 34 around its axis is prevented by the engagement of the planes 34F and 44F.

[0052] In the actuator 30, even when an oblique force is applied to the piston 34 from the coil spring 36, the rotation of the piston 34 is prevented by the flange 40, thus preventing the coil spring 36 from tilting. Furthermore, since the engaging portion 34b of the piston 34 can slide along the axial direction D1 within the inner hole 44 of the flange 40, the piston 34 can be freely moved up and down by controlling the working fluid pressure supplied to the second space S2.

[0053] Therefore, even though the valve 100 is relatively small, it can continuously obtain the thrust designed by the coil spring 36 and operate properly as a fluid-operated valve for high-pressure fluids without degrading its performance.

[0054] As described above, in order to prevent the axial rotation of the piston 34 while allowing the piston 34 to slide smoothly, a friction-reducing layer may be formed between the engagement portion 34b of the piston 34 and the inner hole 44 of the flange 40. The friction-reducing layer may be formed, for example, by a sleeve member made of resin (for example, fluororesin such as PTFE), or by applying grease.

[0055] Furthermore, the shape of the upper surface of the engaging portion 34b and the upper surface of the inner hole 44 of the flange 40 do not necessarily have to be the same, as long as the engagement between the inserted engaging portion 34b and the flange 40 prevents rotation. For example, flat or concave surfaces may be provided on the sides of the engaging portion 34b other than the portion facing the flat surface 44F of the inner hole 44, creating a gap between the engaging portion 34b and the flange 40. Creating a gap reduces sliding resistance and makes centering easier.

[0056] Furthermore, although the above describes an embodiment in which a pair of opposing planes are provided as rotation-preventing surfaces, the number of rotation-preventing surfaces is not limited to two; it may be one or three or more. In the case of three or more surfaces, it is preferable that the rotation-preventing surfaces are arranged evenly along the circumferential direction, that is, symmetrically around the central axis. In addition, the upper surface shape of the engaging portion 34b and the inner hole 44 may be polygonal.

[0057] Furthermore, the rotation-restricting surface is not limited to a flat surface, but may be a curved surface or a combination of a flat and a curved surface, as long as it prevents the rotation of the piston 34 without hindering the axial sliding of the piston 34. Typically, such a rotation-restricting surface is a surface whose cross-section (intersection line) is invariant in any plane perpendicular to the axial direction.

[0058] As shown in Figures 2 and 3, in this embodiment, the engaging portion 34b is provided with multiple cylindrical receiving recesses 34R, each for accommodating the lower ends of multiple coil springs 36. Additionally, the back side of the lid member 32a is provided with multiple cylindrical receiving recesses 32R, each for accommodating the upper ends of multiple coil springs 36. Each coil spring 36 is held between the lid member 32a and the piston 34, with its upper and lower ends supported by the receiving recesses 32R and 34R.

[0059] In the recess 34R housing the coil spring 36, a spring support member may be placed between the lower end of the coil spring 36 and the piston 34 to reduce friction. As the spring support member, for example, an annular thin-walled pure ring, which is a metal plate with a friction-reducing coating, a washer-shaped resin plate, or a thrust bearing can be used. A similar spring support member can also be placed in the recess 32R on the back side of the lid member 32a.

[0060] Although a valve according to an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. For example, the limiting member that engages with the piston's engagement portion to prevent axial rotation of the piston does not necessarily have to be flange-shaped, and may be composed of one or more block members fixed to the housing 32.

[0061] Furthermore, although the above describes a reverse-acting valve in which a coil spring 36 is arranged 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 fluid-acting 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 as well, by fixing a limiting member such as a flange 40 that can engage with the engaging portion 34b of the piston 34 to the housing 32, rotation of the piston 34 and tilting of the coil spring 36 can be prevented, thereby suppressing a decrease in valve performance caused by a decrease in the biasing force on the upper side of the piston during continuous use. [Industrial applicability]

[0062] 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]

[0063] 10 Valve Body 12 valve seats 14 valve chambers 16 Inlet channel 18 Outlet channel 20 valve stems 22 Valve body 24 Support Member 26 rods 30 Actuators 32 cabinets 32a Cylindrical member 32b Cylinder member 32c Lid component 32d Connecting member 34 pistons 36. Coil spring (elastic component) 38 Working fluid inlet 40 Flange (restricting member) 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 its 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 inside the housing so as to be movable along the axial direction, connected to 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 biasing the piston along the axial direction, A working fluid inlet that communicates with the second space and allows the introduction of a working fluid for moving the piston in opposition to the biasing force of the coil spring, A limiting member fixed to the housing and engaging with the piston, configured to prevent rotation of the piston around its axis; A valve equipped with a valve.

2. The limiting member is an annular flange fixed to the housing and having an internal hole, The piston has a cylindrical body portion that is slidable against the inner circumferential surface of the housing, and an engaging portion fixed to the body portion. The valve according to claim 1, wherein the engaging portion of the piston is inserted into the inner hole of the flange, and at least one rotation-restricting surface formed on the inner circumferential surface of the flange and at least one rotation-restricting surface formed on the outer circumferential surface of the engaging portion of the piston engage with each other to prevent the rotation of the piston.

3. The valve according to claim 2, wherein the upper surface shape of the inner hole of the flange and the upper surface shape of the engaging portion of the piston are substantially the same.

4. The valve according to claim 2 or 3, wherein the engagement portion of the piston has a smaller diameter than the main body of the piston.

5. The valve according to claim 2 or 3, wherein the rotation-restricting surface of the flange includes two opposing planes, and the rotation-restricting surface of the piston includes two opposing planes.

6. The housing includes a bottomed cylindrical member having a central hole through which the piston is housed and the valve stem passes, a cylindrical member forming the circumferential surface of the cylindrical internal space, and a lid member covering the end face of the cylindrical member. The valve according to any one of claims 1 to 3, wherein both ends of the plurality of coil springs are housed in a plurality of housing recesses formed in the piston and a plurality of housing recesses formed in the lid member.

7. The valve according to claim 6, wherein the plurality of coil springs are adjacent to each other and arranged symmetrically with respect to the central axis of the housing.

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