Needle valve

Abstract

Provided is a needle valve that is easy to assemble, is exceptional in aligning function, and has high reliability.　A needle valve 10 comprises: a stem 12; a connection member 14 having a neck part 14A that is closely fitted to a distal-end part of the stem 12, and a head part 14B that is supported at the distal end of the neck part 14A; a valve element 16 connected to the stem 12 via the connection member 14; and a fixing member 18. The valve element 16 has a valve element main part 20 and a coating part 22 that is installed in the valve element main part 20 so as to cover the head part 14B of the connection member 14. A gap in a lateral direction orthogonal to an axial direction is provided between the valve element 16 and the connection member 14. The valve element 16 can move in the lateral direction relative to the stem 12 and the connection member 14. Lateral holes 12A, 14C extending in the lateral direction are formed in portions for fitting the stem 12 and the neck part 14A of the connection member 14. The fixing member 18 is inserted into the lateral hole 12A in the stem 12 and the lateral hole 14C in the connection member 14 to fix the connection member 14 to the stem 12.

Description

Needle valve

[0001] The present invention relates to a needle valve used for adjusting a flow rate or the like.

[0002] Needle valves have traditionally been used in various devices and equipment for purposes such as flow rate adjustment. A needle valve includes a rod-shaped stem and a valve element attached to the tip of the stem. The valve element has a conical or spherical side surface with a diameter that decreases toward the tip. The stem moves back and forth along its axial direction, causing the valve element to move away from or abut against an annular valve seat, thereby opening and closing the valve. The flow rate is also adjusted by adjusting the gap between the valve element and the valve seat. If the axial centers of the stem and the valve seat are misaligned, a partial gap will occur even when the valve element abuts the valve seat. Therefore, to ensure reliable valve closure, it is preferable that the axial centers of the stem and the valve seat are aligned with high precision. For example, the axial centers of the stem and the valve seat can be aligned with high precision by forming the guide, which guides the stem so that it can move back and forth along the axial direction, and the valve seat in a common valve body with high precision. Furthermore, the axial centers of the two can be aligned with high precision by separately manufacturing the bonnet, on which the stem guide is formed, and the valve body, on which the valve seat is formed, and then assembling them with high precision. However, in either case, high-precision machining is required, which increases the manufacturing cost of the needle valve.

[0003] In contrast, needle valves are known in which the disc is attached so as to be movable relative to the stem and has an alignment function that adjusts the axis of the disc to coincide with the axis of the valve seat. For example, Patent Document 1 discloses a high-temperature valve including a valve stem with a flange-shaped disc support portion at its lower part, a valve stem including a disc main body member having a support space formed to accommodate the lower part of the valve stem, and a disc engagement member through which the valve stem passes and is threadedly engaged with the disc main body member, and the disc is attached to the valve stem by sandwiching the disc support portion of the valve stem from above and below between the disc main body member and the disc engagement member. A gap is formed between the disc support portion of the valve stem and the disc, and if the axis of the valve stem is misaligned with the axis of the valve seat, the disc tilts relative to the valve stem while abutting against the valve seat, adjusting the disc so that it fits tightly against the valve seat.

[0004] Patent Document 2 also discloses a cryogenic globe valve in which a resin valve element having a tapered conical surface with a reduced diameter is attached to the lower end of a long stem so as to enable three-dimensional movement relative to the stem even under cryogenic conditions. Specifically, an insertion portion (hole) is formed in one of the stem or the valve element, and an attachment portion is formed in the other for insertion into the insertion portion. The insertion portion and the attachment portion are formed with through-holes in a direction intersecting the length of the stem, and a fixing member is inserted into the through-hole, providing a gap between the fixing member and the through-hole. When the resin valve element thermally shrinks, a gap is formed between the insertion portion and the attachment portion, maintaining a clearance that allows the resin valve element to move relative to the gap between the fixing member and the through-hole. When the axis of the stem is inclined relative to the axis of the valve seat, the valve element tilts relative to the stem while abutting the valve seat, adjusting the axis of the valve element to coincide with the axis of the valve seat.

[0005] Patent Document 3 discloses a flow control valve that includes a stem, a valve disc having a columnar portion connected to the stem and an abutment portion with an inclined surface that abuts against the valve seat, and a bolt whose threaded portion screws onto the tip of the stem and whose head is housed in the columnar portion of the valve disc to connect the valve disc to the stem, with a predetermined gap formed between the bolt and the columnar portion of the valve disc in the lateral direction perpendicular to the axis.If the axis of the stem is misaligned with the axis of the valve seat in the lateral direction, the abutment portion of the valve disc moves laterally while abutting against the valve seat, and the axis of the valve disc is adjusted to coincide with the axis of the valve seat.

[0006] JP 2005-321061 A International Publication No. 2020 / 091037 JP 2022-006996 A

[0007] The high-pressure valve disclosed in Patent Document 1 has a spherical lower portion of the disc that contacts the valve seat, and the bottom surface of the support space is also spherical. Therefore, the alignment function is achieved only by rotation of the disc. In other words, lateral movement perpendicular to the axis of the disc is not possible. Therefore, if the lower portion of the disc is a conical needle valve and the axis of the stem and the axis of the disc are, for example, laterally misaligned but parallel, the alignment function is not achieved. Furthermore, the high-temperature valve disclosed in Patent Document 1 has a configuration in which the disc support portion of the valve stem is sandwiched between the disc body member and the disc engagement member that make up the valve disc, which limits assembly work. For example, the disc cannot be attached to the valve stem after the valve stem is attached to the bonnet; the disc must be attached to the valve stem first and then the valve stem must be attached to the bonnet. Furthermore, removing the disc from the valve stem requires removing the valve stem from the bonnet. Furthermore, the attachment and detachment of the disc engagement member and the valve body member is not easy because the long valve stem is inserted into the disc engagement member. Furthermore, in the structure disclosed in Patent Document 1, the diameter of the valve body must be larger than the diameter of the stem, which limits its application to small valves and valves in the low flow rate range.

[0008] The cryogenic globe valve disclosed in Patent Document 2 has a fixing member inserted through a through-hole in the stem and the valve disc, providing a gap between the fixing member and the through-hole. A gap is formed between the insertion portion and the mounting portion at cryogenic temperatures, maintaining the gap between the fixing member and the through-hole, allowing the valve disc to tilt relative to the stem. The valve disc is tilted relative to the stem using the fixing member as a rotation axis, and the axis of the valve disc is adjusted to coincide with the axis of the valve seat. Therefore, the maximum angle at which the valve disc can tilt varies depending on the direction in which the valve disc is tilted relative to the stem. Therefore, depending on the direction in which the axis of the valve disc is adjusted, it may not be possible to align the axis of the valve disc with the axis of the valve seat. Furthermore, if the axis of the stem is misaligned laterally, perpendicular to the axis of the valve seat, it may not be possible to align the axis of the valve disc with the axis of the valve seat. Furthermore, when the valve disc rotates with the stem and abuts against the valve seat, friction between the contact surfaces of the valve disc and the valve seat inhibits stem rotation. Meanwhile, depending on the device or equipment in which a needle valve is used, installation space and other factors may necessitate a small handle for rotating the stem. In such a case, it may be difficult to apply a strong rotational force to the stem, and the valve disc may not be pushed down to the completely closed position.

[0009] The flow control valve disclosed in Patent Document 3 has a configuration in which a bolt is threaded onto the tip of the stem, which may loosen over time and cause the valve element to fall off the stem. In the case of a needle valve in which the stem rotates around an axis while moving back and forth in the axial direction, such as a manual needle valve, the bolt is likely to loosen. In particular, when the valve element moves away from the valve seat or abuts against the valve seat, the stem rotates while the valve element's rotation is restricted by friction with the valve seat, which is likely to cause the bolt to loosen. The flow control valve disclosed in Patent Document 3 is configured so that the stem moves back and forth in the axial direction without rotating around the axis, and no consideration is given to the problem of bolt loosening. Furthermore, because the valve element and stem are pressed against each other by the tightening force of the bolt, the friction at the abutting surface between the valve element and the stem may restrict the movement of the valve element relative to the stem. While reducing the tightening force of the bolt can reduce the friction at the abutting surface between the valve element and the stem, it is likely that the bolt will loosen more easily. The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a needle valve that is easy to assemble, has excellent alignment function, and is highly reliable.

[0010] The present invention solves the above-mentioned problems by providing a needle valve comprising a stem, a connecting member having a neck that fits tightly onto the tip of the stem and a head supported on the tip of the neck, a valve body connected to the stem via the connecting member, and a fixing member that fixes the connecting member to the stem, wherein the valve body has a valve body main portion and a covering portion that has a through hole formed therein through which the neck of the connecting member is inserted and is installed on the side of the valve body main portion facing the stem so as to cover the head of the connecting member, a lateral gap perpendicular to the axial direction is provided between the valve body and the connecting member, the valve body is movable laterally within a certain range relative to the stem and the connecting member, a lateral hole extending laterally is formed at the fitting portion between the stem and the neck of the connecting member, and the fixing member is inserted into the lateral hole of the stem and the lateral hole of the neck of the connecting member to fix the connecting member to the stem.

[0011] This needle valve connects the stem and valve element via a connecting member, allowing the head of the connecting member and the valve element to be designed in any size regardless of the stem diameter. This eliminates the size constraints on the valve element, as in the structure disclosed in Patent Document 1. Furthermore, the neck of the connecting member fits tightly against the tip of the stem, and the fixing member is inserted into the lateral holes of the stem and the neck of the connecting member to secure the connecting member to the stem. This prevents the valve element from being pressed firmly against the stem when it is connected to the stem via the connecting member. Therefore, during alignment, the valve element can move smoothly laterally relative to the stem and connecting member. Furthermore, because the valve element can be guided by both the head of the connecting member and the tip of the stem, it is easy to maintain the valve element in the desired position during alignment. Therefore, this needle valve has excellent alignment capabilities. Furthermore, during assembly, the neck of the connecting member is inserted through the covering portion of the valve element, and the covering portion is attached to the main portion of the valve element. The work of attaching the covering portion to the valve body main portion is easier than when the covering portion is attached to the valve body main portion with a long stem inserted through the covering portion of the valve body. Also, by fitting the neck portion of the connecting member to the tip of the stem and inserting a fixing member into the lateral hole of the fitting portion, the valve body can be easily attached to the stem via the connecting member. It is also possible to attach and detach the valve body to the stem while the stem is attached to the bonnet.

[0012] The stem may be configured to move back and forth in the axial direction while rotating about its axis, and the stem and the connecting member may be rotatable relative to the valve body.

[0013] Even in cases where the stem rotates around its axis while moving back and forth in the axial direction, as in a manual needle valve, the fixing member is inserted into the lateral hole in the stem and the lateral hole in the neck of the connecting member to fix the connecting member to the stem, so the connecting member will not come off the stem due to stem rotation. The stem and connecting member are also rotatable relative to the valve body. Furthermore, when the valve body is connected to the stem via the connecting member as described above, the valve body is not pressed strongly against the stem. Therefore, the stem and connecting member can rotate smoothly relative to the valve body, and the valve body can be pushed down to the fully closed position even if it is difficult to apply a strong rotational force to the stem.

[0014] In this case, the device may further include a bonnet that houses the stem and a handle for manually rotating the stem, the handle having a width smaller in the lateral direction than the bonnet.

[0015] The compact design of the handle, with a width smaller than that of the bonnet, allows for greater flexibility in the installation design of the needle valve in equipment and facilities. Even if the handle is small and it is difficult to apply a strong rotational force to the stem, the disc can be pushed down to the fully closed position as described above. Furthermore, because the disc can move smoothly laterally relative to the stem and connecting member during alignment, the valve can be reliably aligned and closed even if the handle is small and the force required to abut the disc against the valve seat is small.

[0016] The contact surface between the valve body and the valve seat may be a conical surface, and the inclination angle of the conical surface relative to the axis may be in the range of 5 to 15 degrees.

[0017] If the contact surface between the valve disc and the valve seat is a conical surface and the inclination angle of the conical surface relative to the axis is in the range of 5 to 15 degrees, the force that contacts the valve disc with the valve seat can be made large even if the force pressing down on the stem is weak, and the valve can be closed by reliably bringing the valve disc and valve seat into close contact.

[0018] The device may further include a guide portion that guides the stem so that it can slide freely, and the fixing member may be configured to be always located within the guide portion within the range in which the stem moves back and forth in the axial direction.

[0019] By configuring the fixing member so that it is always positioned within the guide portion, it is possible to reliably prevent the fixing member from falling off the stem.

[0020] The valve may further include a bonnet that houses the stem, a valve seat member that is fitted into and attached to the valve body to which the bonnet is attached, and a valve seat retaining spacer that is interposed between the bonnet and the valve seat member to retain the valve seat member.

[0021] Because the valve seat member is separate from the valve body, it is easy to machine the contact surface with the valve disc, etc. Also, because the valve seat member is configured to fit into the valve body, it is easy to machine the valve body and also to attach the valve seat member to the valve body. Furthermore, the simple configuration in which the valve seat retaining spacer is interposed between the bonnet and the valve seat member ensures that the valve seat member is securely held in the installed position on the valve body.

[0022] According to the present invention, a needle valve that is easy to assemble, has excellent alignment function, and is highly reliable can be realized.

[0023] FIG. 1 is a cross-sectional view showing the structure of a needle valve according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view showing an enlarged view of the valve disc and its periphery of the needle valve; FIG. 3 is a perspective view showing the overall structure of a piping assembly in which the needle valve is installed; FIG. 4 is a cross-sectional view showing an enlarged view of the contact portion between the valve disc and valve seat of the needle valve; FIG. 5 is a cross-sectional view showing a state in which the axial centers of the stem and valve disc of the needle valve are laterally shifted relative to the axial center of the valve seat;

[0024] 1 and 2 , a needle valve 10 of the first embodiment includes a stem 12, a connecting member 14 having a neck portion 14A that fits closely to the tip of the stem 12 and a head portion 14B supported at the tip of the neck portion 14A, a valve element 16 connected to the stem 12 via the connecting member 14, and a fixing member 18 that fixes the connecting member 14 to the stem 12. The valve element 16 includes a valve element main portion 20 and a covering portion 22 that has a through hole through which the neck portion 14A of the connecting member 14 is inserted and is installed on the side of the valve element main portion 20 facing the stem 12 so as to cover the head portion 14B of the connecting member 14. A lateral gap perpendicular to the axial direction is provided between the valve element 16 and the connecting member 14, allowing the valve element 16 to move laterally within a certain range relative to the stem 12 and the connecting member 14. Horizontal holes 12A and 14C extending laterally are formed at the mating portion between the stem 12 and the neck 14A of the connecting member 14, and the fixing member 18 is inserted into the horizontal hole 12A of the stem 12 and the horizontal hole 14C of the neck 14A of the connecting member 14 to fix the connecting member 14 to the stem 12.

[0025] The needle valve 10 further includes a bonnet 24 that houses the stem 12 and a handle 26 for manually rotating the stem 12 .

[0026] The stem 12 is a stepped rod-like body tapered in three stages from the distal end to the proximal end, and is composed of a distal portion, an intermediate portion, and a proximal portion. The stem 12 is made of metal. A vertical hole 12B extending axially is formed at the tip of the distal portion. The neck portion 14A of the connecting member 14 is tightly fitted into the vertical hole 12B. A horizontal hole 12A is formed on the outer peripheral surface near the distal end of the distal portion so as to communicate with the vertical hole 12B. Two horizontal holes 12A are formed symmetrically about the axis of the stem 12 in the distal portion. A groove 12C is formed circumferentially on the outer peripheral surface of the distal portion, closer to the proximal end than the horizontal hole 12A. An O-ring 28 is attached to the groove 12C. A male thread is formed on the outer peripheral surface of the intermediate portion, which threads into the female thread of the bonnet 24. A handle 26 is attached to the proximal portion.

[0027] The bonnet 24 has a substantially square, plate-shaped base portion 24A and a guide portion 24B that slidably guides the stem 12. The bonnet 24 is made of resin or metal. A through hole is formed in the center of the base portion 24A, through which the stem 12 passes. The guide portion 24B is a cylindrical body formed coaxially with the through hole at the center of one surface of the base portion 24A. The guide portion 24B is integrally formed with the base portion 24A. The tip portion of the stem 12 slidably fits inside the guide portion 24B. The gap between the inner surface of the guide portion 24B and the outer surface of the tip portion of the stem 12 is sealed with an O-ring 28. In addition, an annular boss is formed coaxially with the through hole at the center of the other surface of the base portion 24A. A female thread is formed on the inner surface of the through hole in the base portion 24A. The male thread in the middle portion of the stem 12 is threaded into this female thread. The bonnet 24 is attached to the valve body 30 by screws (not shown) near the four corners.

[0028] The handle 26 is a disk-shaped body that is coaxially installed on the base end portion of the stem 12 and is fixed to the stem 12 with a screw 31. The handle 26 is made of resin or metal. The diameter (lateral width) of the handle 26 is smaller than the lateral width of the bonnet 24. By rotating the handle 26, the stem 12 rotates around its axis while moving back and forth in the axial direction. The stem 12 and the connecting member 14 are rotatable relative to the valve body 16.

[0029] The neck portion 14A of the connecting member 14 is a round rod-shaped body having a horizontal hole 14C formed therein that communicates with the horizontal hole 12A. The head portion 14B of the connecting member 14 is a disk-shaped body that is coaxially installed at the tip of the neck portion 14A. The head portion 14B is formed integrally with the neck portion 14A. The connecting member 14 is made of a metal such as stainless steel.

[0030] The fixing member 18 is a spring pin (roll pin). Specifically, the fixing member 18 is a cylindrical member with a circumferential portion cut out along the longitudinal direction. The fixing member 18 is tightly fitted into the lateral hole 14C of the neck portion 14A of the connecting member 14. Meanwhile, there is a small gap between the fixing member 18 and the lateral hole 12A of the stem 12. The fixing member 18 may be tightly fitted into the lateral hole 12A of the stem 12, with a small gap between the fixing member 18 and the lateral hole 14C of the neck portion 14A of the connecting member 14. In these cases, the fixing member 18 can be easily inserted into the lateral hole 12A of the stem 12 and the lateral hole 14C of the neck portion 14A of the connecting member 14. Alternatively, the fixing member 18 may be tightly fitted into both the lateral hole 14C of the neck portion 14A of the connecting member 14 and the lateral hole 12A of the stem 12. In this case, for example, by forming the lateral holes 12A and 14C while the stem 12 and the neck portion 14A of the connecting member 14 are engaged, the two lateral holes can be aligned with high precision. The fixing member 18 may also be a cylindrical pin without a notch. The fixing member 18 may also be a solid round bar pin. The fixing member 18 may also be engaged with the stem 12 at only one circumferential position on the stem 12. In this case, the lateral hole 12A of the stem 12 may be formed at only one circumferential position. The fixing member 18 may also be a screw. For example, the fixing member 18 may have a male thread in the portion inserted into the lateral hole 14C of the neck portion 14A of the connecting member 14, and a stepped round bar-like member with a larger diameter than the male thread in the portion inserted into the lateral hole 12A of the stem 12. In this case, a female thread is formed in the lateral hole 14C of the neck portion 14A of the connecting member 14. The fixing member 18 may also be a stepped round rod-like member in which the portion inserted into the horizontal hole 12A of the stem 12 is male-threaded, and the portion inserted into the horizontal hole 14C of the neck portion 14A of the connecting member 14 is thinner than the male-threaded portion. In this case, a female thread is formed in the horizontal hole 12A of the stem 12. Furthermore, when the fixing member 18 is a screw, a flat-head or hexagonal recess is formed in the end of the fixing member 18 to be engaged with a tool.

[0031] The valve body main portion 20 of the valve body 16 has a generally truncated conical shape, with the outer circumferential surface having a conical surface with a diameter that decreases toward the tip from the portion near the base end. The valve body 16 is adapted to abut against the valve seat (described below) at this conical surface. In this specification, the term "needle valve" refers to a valve having a conical or spherical outer circumferential surface with a diameter that decreases toward the tip, and which opens and closes by axially moving the valve body back and forth to separate from or abut against the valve seat. This term is not limited to valves with elongated needle-shaped valves. The outer circumferential surface of the valve body main portion 20 near the base end is cylindrical. A circular recess 20A is formed in the base end portion of the valve body main portion 20 to accommodate the head 14B of the connecting member 14. Furthermore, an annular recess 20B is formed around the recess 20A to accommodate the covering portion 22 of the valve body 16. The radially outer portion of the recess 20B is deeper than the inner circumferential portion. The material of the valve body main portion 20 is a resin such as POM (polyoxymethylene) or a metal.

[0032] The covering portion 22 of the valve element 16 is a ring-shaped plate that fits into and is fixed in the recess 20B of the valve element main portion 20. The thickness of the covering portion 22 and the depth of the inner periphery of the recess 20B are approximately equal. As a result, the surface of the covering portion 22 facing the stem 12 and the surface of the valve element main portion 20 facing the stem 12 form a flat surface with almost no steps. The outer periphery of the covering portion 22 protrudes toward the tip and extends radially outward from the inner periphery of the recess 20B. The covering portion 22 is also made of a resin such as POM (polyoxymethylene) or a metal. If the valve element main portion 20 and the covering portion 22 are made of a resin, the covering portion 22 is fixed to the valve element main portion 20 by welding, adhesive bonding, or press-fitting. If the valve element main portion 20 and the covering portion 22 are made of a metal, the covering portion 22 is fixed to the valve element main portion 20 by welding, brazing, adhesive bonding, or press-fitting.

[0033] The diameter of the through hole in the covering portion 22 is larger than the diameter of the neck portion 14A of the connecting member 14. The diameter of the recess 20A in the valve body main portion 20 is larger than the diameter of the head 14B of the connecting member 14. This creates a lateral gap perpendicular to the axial direction between the valve body 16 and the connecting member 14. The diameter of the through hole in the covering portion 22 is smaller than the diameter of the head 14B of the connecting member 14. The axial gap between the bottom surface of the recess 20A in the valve body main portion 20 and the covering portion 22 is larger than the thickness of the head 14B of the connecting member 14. This creates an axial gap between the valve body 16 and the head 14B of the connecting member 14. The axial gap between the valve body 16 and the head 14B of the connecting member 14 allows the valve body 16 to move smoothly laterally relative to the head 14B of the connecting member 14 during alignment. The valve body 16 can also tilt within a certain range relative to the stem 12 and the connecting member 14. When the axis of the stem 12 is inclined relative to the axis of the valve seat 32, the inclination of the valve element 16 allows it to be in intimate contact with the valve seat 32. The stem 12 is configured so that the tip of the stem 12 abuts against the base end of the valve element 16 when the head 14B of the connecting member 14 abuts against the bottom surface of the recess 20A of the valve element main portion 20. This allows the valve element 16 to be guided by both the head 14B of the connecting member 14 and the tip of the stem 12, making it easier to maintain the valve element 16 in a desired position during alignment. Alternatively, the tip of the stem 12 may be configured to be spaced axially away from the base end of the valve element 16 when the head 14B of the connecting member 14 abuts against the bottom surface of the recess 20A of the valve element main portion 20. In this case, too, the tip of the stem 12 functions as a guide that limits the upper limit of the inclination angle of the valve element 16. Furthermore, the head 14B of the connecting member 14 may be configured to be spaced axially away from the bottom surface of the recess 20A of the valve body main portion 20 when the tip of the stem 12 is in contact with the base end of the valve body 16. In this case, the tip of the stem 12 functions as the main guide during alignment. The head 14B of the connecting member 14 may be sandwiched between the valve body main portion 20 (the bottom surface of the recess 20A) and the covering portion 22, so that no gap is formed in the axial direction between the valve body 16 and the head 14B of the connecting member 14. In this case, the valve body 16 can be guided laterally to prevent it from tilting.In this case, if the tip of the stem 12 is configured to abut against the base end of the valve element 16, the valve element 16 can be guided laterally more reliably to prevent tilting. Note that, if the valve element 16 can be guided laterally by the head 14B of the connecting member 14 alone to prevent tilting, the tip of the stem 12 may be configured to be spaced axially away from the base end of the valve element 16.

[0034] As shown in FIG. 3 , the needle valve 10 is installed in a piping assembly unit 50. The piping assembly unit 50 includes an inlet main channel 52, multiple inlet branch channels 54 connected downstream of the inlet main channel 52, an outlet main channel 56, and multiple outlet branch channels 58 connected upstream of the outlet main channel 56. The number of inlet branch channels 54 and the number of outlet branch channels 58 are the same, and each inlet branch channel 54 is connected to one outlet branch channel 58 via a pipe (not shown). Cooling water (fluid) received by the inlet main channel 52 is supplied to a cooling target (not shown) via the multiple inlet branch channels 54. The cooling target is, for example, a dry etching device or a film formation device used in semiconductor manufacturing. The cooling water, whose temperature has increased after cooling the cooling target, is discharged from the outlet main channel 56 via the multiple outlet branch channels 58. The cooling water discharged from the outlet main channel 56 has its temperature adjusted by a chiller (not shown) and is then supplied back to the inlet main channel 52. An on-off valve 66 is installed in each inlet branch flow path 54 .

[0035] A needle valve 10 is installed in each outlet branch flow path 58. A drain valve 60 and a flow meter 62 are also installed in each outlet branch flow path 58. The needle valves 10, drain valves 60, and flow meter 62 are installed adjacent to each other along the outlet branch flow path 58. A plurality of sets of the needle valves 10, drain valves 60, and flow meter 62 are installed adjacent to each other corresponding to the plurality of outlet branch flow paths 58. A plurality of needle valves 10 are installed adjacent to each other along the outlet main flow path 56. A plurality of drain valves 60 are installed adjacent to each other along the common drain flow path 64. The drain valve 60 is switchable between an operation mode in which the port on the flow meter 62 side is connected to the port on the needle valve 10 side and the port on the common drain flow path 64 side is not connected to these two ports, and a maintenance mode in which the port on the flow meter 62 side is connected to the port on the common drain flow path 64 side and the port on the needle valve 10 side is not connected to the other two ports. The needle valve 10 is used to adjust the flow rate of the cooling water flowing from the outlet branch passage 58 to the outlet main passage 56 or to cut off the flow.

[0036] The valve body 30, to which the bonnet 24 of the needle valve 10 is attached, constitutes part of the outlet main flow path 56 and the outlet branch flow path 58. The portion of the valve body 30 opposite the outlet branch flow path 58 is closed by a cover member 68. The valve body 30 is formed with a valve seat 32 that abuts against the valve disc 16. As shown in FIG. 4 , the abutment surfaces of the valve disc main portion 20 of the valve disc 16 and the valve seat 32 are both conical surfaces, and the inclination angle of the conical surface relative to the axis is in the range of 5 to 15 degrees. The inclination angle of the conical surface of the valve disc main portion 20 of the valve disc 16 relative to the axis is equal to the inclination angle of the conical surface of the valve seat 32 relative to the axis. For example, the inclination angle of the conical surface of the valve disc main portion 20 of the valve disc 16 relative to the axis is 10 degrees, and the inclination angle of the conical surface of the valve seat 32 relative to the axis is also 10 degrees. The angle of inclination of the conical surface of the valve body main portion 20 of the valve body 16 relative to the axis may be different from the angle of inclination of the conical surface of the valve seat 32 relative to the axis.

[0037] Next, the effects of the needle valve 10 will be described. Due to errors and the like that occur during the manufacturing process, the axis C2 of the stem 12 may be laterally misaligned with the axis C1 of the valve seat 32, as shown in Figure 5. In this case, when the valve disc 16 abuts against the valve seat 32 to close the valve, the valve disc 16 is urged laterally by the reaction force of the conical surface abutting the valve seat 32, and moves laterally relative to the stem 12 and connecting member 14. As a result, as shown in Figure 6, even if the axis C2 of the stem 12 is laterally misaligned with the axis C1 of the valve seat 32, the axis of the valve disc 16 will coincide with the axis C1 of the valve seat 32, and the valve will close. The needle valve 10 is configured such that the neck portion 14A of the connecting member 14 fits closely to the tip of the stem 12, and the fixing member 18 is inserted into the lateral hole 12A of the stem 12 and the lateral hole 14C of the neck portion 14A of the connecting member 14 to fix the connecting member 14 to the stem 12. Therefore, when the valve disc 16 is connected to the stem 12 via the connecting member 14, the valve disc 16 is not pressed strongly against the stem 12. Therefore, the valve disc 16 can move smoothly laterally relative to the stem 12 and the connecting member 14 during alignment. Furthermore, because the valve disc 16 can be guided by both the head portion 14B of the connecting member 14 and the tip of the stem 12, the valve disc 16 can be easily maintained in a desired position during alignment. Therefore, the needle valve 10 has excellent alignment capabilities. Furthermore, if an axial gap is formed between the valve disc 16 and the head portion 14B of the connecting member 14, the valve disc 16 can tilt within a certain range relative to the stem 12 and the connecting member 14. Therefore, even if the axis C2 of the stem 12 is inclined relative to the axis C1 of the valve seat 32, the axis of the valve element 16 will coincide with the axis C1 of the valve seat 32 and the valve will close.

[0038] Furthermore, the needle valve 10 is configured such that the stem 12 moves back and forth in the axial direction while rotating about its axis. However, the fixing member 18 is inserted into the horizontal hole 12A of the stem 12 and the horizontal hole 14C of the neck portion 14A of the connecting member 14 to fix the connecting member 14 to the stem 12, so that the connecting member 14 will not come off the stem 12 due to the rotation of the stem 12. The stem 12 and connecting member 14 are also rotatable relative to the valve disc 16. Furthermore, when the valve disc 16 is connected to the stem 12 via the connecting member 14 as described above, the valve disc 16 is not pressed strongly against the stem 12. Therefore, the stem 12 and connecting member 14 can rotate smoothly relative to the valve disc 16, and the valve disc 16 can be pushed down to the fully closed position even if it is difficult to apply a strong rotational force to the stem 12.

[0039] Furthermore, the needle valve 10 has a compact configuration in which the handle 26 is narrower in width than the bonnet 24, allowing for greater flexibility in the installation design of the needle valve in equipment and facilities. For example, when multiple needle valves 10 are installed adjacent to each other, such as in a piping assembly unit 50, or when a drain valve 60 or a flow meter 62 is installed adjacent to a needle valve 10, the layout of these components can be designed with greater flexibility, allowing for a compact overall piping assembly unit 50. Furthermore, even if the handle 26 is small and it is difficult to apply a strong rotational force to the stem 12, the valve disc 16 can be pushed down to the fully closed position as described above. Furthermore, because the valve disc 16 can move smoothly laterally relative to the stem 12 and connecting member 14 during alignment, the valve can be reliably aligned and closed even when the handle 26 is small and the force required to abut the valve disc 16 against the valve seat 32 is small.

[0040] During assembly, the covering portion 22 is attached to the valve body main portion 20 with the neck portion 14A of the connecting member 14 inserted through the covering portion 22 of the valve body 16. This makes the work of attaching the covering portion 22 to the valve body main portion 20 easier than when the covering portion 22 is attached to the valve body main portion 20 with the long stem 12 inserted through the covering portion 22 of the valve body 16. Furthermore, by fitting the neck portion 14A of the connecting member 14 to the tip of the stem 12 and inserting the fixing member 18 into the horizontal holes 12A, 14C of the fitting portion, the valve body 16 can be easily attached to the stem 12 via the connecting member 14. The valve body 16 can also be attached to and detached from the stem 12 with the stem 12 attached to the bonnet 24.

[0041] Next, a second embodiment will be described. In the needle valve 10 of the first embodiment, the lateral hole 12A of the stem 12 is formed near the distal end of the distal portion. In contrast, as shown in FIG. 7 , in the needle valve 70 of the second embodiment, the lateral hole 72A of the stem 72 is formed near the proximal end of the distal portion. This allows the fixing member 18 to be constantly positioned within the guide portion 24B within the range of axial movement of the stem 72. The distal portion of the stem 72 is longer than the distal portion of the stem 12 of the first embodiment. The lateral hole 72A is formed proximally of the groove 72C in which the O-ring 28 is attached. The neck portion 74A of the connecting member 74 is also longer than the neck portion 14A of the connecting member 14 of the first embodiment. A groove 74D is formed in the neck portion 74A of the connecting member 74 distal to the lateral hole 74C, running along the circumferential direction. An O-ring 76 is attached to the groove 74D. The gap between the inner peripheral surface of the vertical hole 72B of the stem 72 and the outer peripheral surface of the neck portion 74A of the connecting member 74 is sealed with an O-ring 76. Since the other configurations are the same as those in the first embodiment, the same components are given the same reference numerals as in Figures 1 to 6 and their description will be omitted. By configuring the fixing member 18 to always be positioned within the guide portion 24B in this way, it is possible to reliably prevent the fixing member 18 from falling off the stem 72.

[0042] Next, a third embodiment will be described. As shown in FIG. 8 , a needle valve 80 of the third embodiment includes a valve seat member 84 that is fitted to a valve body 82 to which the bonnet 24 is attached, and a valve seat retaining spacer 86 that is interposed between the bonnet 24 and the valve seat member 84 to retain the valve seat member 84. The valve seat member 84 is generally cylindrical, with a valve seat 84A formed on the inner circumferential surface of the base end. The valve seat 84A has the same conical shape as the valve seat 32 of the first embodiment. A groove 84B is formed in the outer circumferential surface of the valve seat member 84 along the circumferential direction. An O-ring 88 is attached to the groove 84B. The outer circumferential surface of the valve seat member 84 has a stepped shape, with the outer diameter of the portion near the base end being larger than the remaining portion. The valve seat member 84 is made of resin or metal. The portion of the valve body 82 where the valve seat member 84 is installed (the portion adjacent to the outlet main flow path 56 of the collecting piping unit) has a stepped, generally cylindrical surface that corresponds to the outer circumferential surface of the valve seat member 84. The valve seat member 84 fits into this portion, and movement in the direction of insertion into the valve body 82 (direction away from the bonnet 24) is prevented by the stepped shape of the valve body 82. The material of the valve body 82 is resin or metal.

[0043] The valve seat retaining spacer 86 is generally cylindrical and is open at a portion adjacent to the outlet branch flow path 58 of the piping assembly 50 (the portion on the left side in FIG. 8 ). The tip of the valve seat retaining spacer 86 faces the boundary between the base end of the valve seat member 84 and the valve body 82, with one portion abutting or adjacent to the base end of the valve seat member 84 and the other portion abutting or adjacent to the valve body 82. Meanwhile, the base end of the valve seat retaining spacer 86 engages with the tip of the guide portion 24B of the bonnet 24. More specifically, the inner circumferential surface of the valve seat retaining spacer 86 has a stepped shape with a diameter larger than the outer circumferential surface of the guide portion 24B near the base end and a diameter smaller than the outer circumferential surface of the guide portion 24B elsewhere. The valve seat retaining spacer 86 engages with the tip portion of the guide portion 24B at this stepped portion. The valve seat member 84 is also prevented from moving in the direction in which it would be removed from the valve body 82 (towards the bonnet 24) by a valve seat retaining spacer 86, and is held in an installed position in the valve body 82. The valve seat retaining spacer 86 is made of resin or metal. As the other configuration is the same as in the first embodiment, the same components as in Figures 1 to 6 are denoted by the same reference numerals and description thereof will be omitted.

[0044] Because the valve seat member 84 is separate from the valve body 82, the valve seat 84A and the like can be easily machined. Moreover, because the valve seat member 84 is configured to fit into the valve body 82, the valve body 82 can be easily machined, and the valve seat member 84 can also be easily attached to the valve body 82. Furthermore, the valve seat retaining spacer 86 has a simple configuration in which it is interposed between the guide portion 24B of the bonnet 24 and the valve seat member 84, thereby reliably holding the valve seat member 84 in the installed position. Note that, although the valve seat retaining spacer 86 is interposed between the guide portion 24B of the bonnet 24 and the valve seat member 84 in the third embodiment, the valve seat retaining spacer 86 may be interposed between another portion of the bonnet and the valve seat member.

[0045] Next, a fourth embodiment will be described. The needle valves 10, 70, and 80 of the first to third embodiments are manually operated and equipped with a handle 26, and the stems 12 and 72 are configured to move forward and backward in the axial direction while rotating about their axes. In contrast, as shown in FIG. 9 , the needle valve 90 of the fourth embodiment is electrically operated and equipped with a motor 100, and the stem 92 is configured to move forward and backward in the axial direction without rotating about its axis. The stem 92 is a stepped round rod-like body that becomes thicker in two stages from the tip to the base end, and is composed of a tip end portion and a base end portion. The tip end portion of the stem 92 has the same configuration as the tip end portion of the stem 12 of the first embodiment. The base end portion of the stem 92 is cylindrical, and a female thread is formed on the inner circumferential surface.

[0046] The bonnet 94 has a substantially square, plate-shaped base portion 94A, a guide portion 94B that slidably guides the distal end portion of the stem 92, and a guide portion 94C that slidably guides the proximal end portion of the stem 92. The guide portion 94B is formed on one side of the base portion 94A, and the guide portion 94C is formed on the other side of the base portion 94A. The bonnet 94 has a stepped through-hole that corresponds to the stepped, round rod-shaped stem 12. The guide portion 94C engages with the stem 92 via an axial spline or the like (not shown), allowing the stem 92 to move back and forth in the axial direction without rotating about its axis.

[0047] A male screw member 96 is threaded into the female screw on the inside of the base end portion of the stem 92. The male screw member 96 is connected to the rotary shaft of a motor 100. The motor 100 is attached to the end of a guide portion 94C of the bonnet 94. When the male screw member 96 rotates together with the rotary shaft of the motor 100, the stem 92 moves forward and backward in the axial direction without rotating about the axis. As the other configurations are the same as those in the first embodiment, the same components as those in Figures 1 to 6 are assigned the same reference numerals and description thereof will be omitted.

[0048] Even when the stem 92 is configured to move axially back and forth without rotating about its axis, the valve disc 16 is not pressed strongly against the stem 92 when connected to the stem 92 via the connecting member 14, allowing the valve disc 16 to move smoothly laterally relative to the stem 92 and connecting member 14 during alignment. Furthermore, because the valve disc 16 can be guided by both the head 14B of the connecting member 14 and the tip of the stem 92, it is easy to maintain the valve disc 16 in the desired position during alignment. Therefore, the needle valve 90 also has excellent alignment function.

[0049] The present invention can also be applied to an electrically operated needle valve equipped with a motor, in which the stem rotates about an axis and moves back and forth in the axial direction. For example, the present invention can be applied to a needle valve in which a motor for rotating the stem 12, 72 is attached instead of the handle 26 of the needle valves 10, 70, 80 of the first to third embodiments.

[0050] Furthermore, in the first to fourth embodiments, vertical holes 12B, 72B are formed at the tip portions of the stems 12, 72, 92, and the neck portions 14A, 74A of the connecting members 14, 74 are inserted closely into the vertical holes 12B, 72B of the stems 12, 72, 92, thereby fitting closely to the tip portions of the stems 12, 72, 92, but a vertical hole may be formed at the base end of the neck portion of the connecting member, and the tip portion of the stem may be inserted into the vertical hole in the neck portion of the connecting member, so that the neck portion of the connecting member fits closely to the tip portion of the stem.

[0051] Furthermore, in the first to fourth embodiments, the covering portion 22 of the valve body 16 fits into the recess 20B of the valve body main portion 20, and the surface of the covering portion 22 facing the stem 12, 72, 92 and the surface of the valve body main portion 20 facing the stem 12, 72, 92 form a flat surface with almost no steps, but a configuration may also be adopted in which there is no recess 20B and there is a step between the surface of the covering portion 22 facing the stem and the surface of the valve body main portion 20 facing the stem 12, 72, 92. Furthermore, in the first to fourth embodiments, a circular recess 20A is formed in the base end side portion of the valve body main portion 20 to accommodate the heads 14B, 74B of the connecting members 14, 74, but a configuration in which there is no recess 20A and the covering portion accommodates the heads 14B, 74B of the connecting members 14, 74 may also be adopted. For example, the covering portion may be configured to have a disk-shaped body having a through hole through which the neck portion 14A, 74A of the connecting member 14, 74 passes and which is close to or abuts the stem side surface of the head portion 14B, 74B of the connecting member 14, 74, and a cylindrical peripheral wall which surrounds the outer peripheral surface of the head portion 14B, 74B of the connecting member 14, 74.

[0052] In the first to third embodiments, the handle 26 is disk-shaped, but the shape of the handle is not particularly limited. In the first to third embodiments, the handle 26 has a smaller diameter (lateral width) than the bonnet 24, but the present invention is also applicable to a needle valve in which the diameter (lateral width) of the handle is larger than the diameter (lateral width) of the bonnet 24.

[0053] Furthermore, in the first to fourth embodiments, the guide portions 24B, 94B, 94C that guide the stems 12, 72, 92 in the axial direction are installed in the bonnets 24, 94, and the valve seats 32, 84A are installed in the valve bodies 30, 82, but the present invention is also applicable to needle valves in which the guide portions that guide the stems in the axial direction and the valve seats are installed in a common valve body.

[0054] Furthermore, in the first to fourth embodiments, the outer peripheral surface of the valve body main portion 20 of the valve body 16 is a conical surface whose diameter decreases toward the tip, but the present invention is also applicable to a needle valve in which the outer peripheral surface of the valve body main portion is a spherical surface whose diameter decreases toward the tip.

[0055] Furthermore, in the first to fourth embodiments, the diameter of the valve body 16 is larger than the diameter of the stem 12, but the present invention is also applicable to needle valves in which the diameter of the valve body is equal to the diameter of the stem, or needle valves in which the diameter of the valve body is smaller than the diameter of the stem.

[0056] Furthermore, in the first to fourth embodiments, examples are shown in which the needle valves 10, 70, 80, and 90 are installed in the piping assembly unit 50, but the needle valve of the present invention can be applied to various devices and equipment.

[0057] The present invention can be used to adjust the flow rate or shut off the flow of fluids such as cooling water in various devices and facilities.

[0058] 10, 70, 80, 90 Needle valve 12, 72, 92 Stem 12A, 14C, 72A, 74C Horizontal hole 12B, 72B Vertical hole 12C Groove 14, 74 Connecting member 14A, 74A Neck portion 14B Head portion 16 Valve body 18 Fixing member 20 Valve body main portion 22 Covering portion 24 Bonnet 24A, 94A Base portion 24B, 94B, 94C Guide portion 26 Handle 28, 76, 88 O-ring 30, 82 Valve body 32, 84A Valve seat 50 Collecting piping unit 52 Inlet main flow path 54 Inlet branch flow path 56 Outlet main flow path 58 Outlet branch flow path 60 Drain valve 62 Flow meter 64 Common drain flow path 66 Opening / closing valve 68 Cover member 84 Valve seat member 84B Groove 86 Valve seat retaining spacer 96 Male thread member 100 Motor

Claims

1. A needle valve comprising: a stem; a connecting member having a neck portion that fits tightly onto the tip portion of the stem and a head portion supported on the tip of the neck portion; a valve body connected to the stem via the connecting member; and a fixing member that fixes the connecting member to the stem, wherein the valve body has a valve body main portion and a covering portion that has a through hole through which the neck portion of the connecting member is inserted and is installed on the side of the valve body main portion facing the stem so as to cover the head of the connecting member, wherein a lateral gap perpendicular to the axial direction is provided between the valve body and the connecting member, and the valve body is movable in the lateral direction relative to the stem and the connecting member within a certain range, and a lateral hole extending in the lateral direction is formed at the fitting portion between the stem and the neck portion of the connecting member, and the fixing member is inserted into the lateral hole of the stem and the lateral hole of the neck of the connecting member to fix the connecting member to the stem.

2. A needle valve according to claim 1, wherein the stem is configured to move back and forth in the axial direction while rotating around its axis, and the stem and the connecting member are rotatable relative to the valve body.

3. A needle valve according to claim 2, further comprising a bonnet that houses the stem, and a handle for manually rotating the stem, the handle having a width in the lateral direction smaller than that of the bonnet.

4. A needle valve according to claim 1, wherein the contact surface between the valve body and the valve seat is a conical surface, and the inclination angle of the conical surface relative to the axis is in the range of 5 to 15 degrees.

5. A needle valve according to claim 1, further comprising a guide portion for slidably guiding the stem, and configured so that the fixed member is always positioned within the guide portion within the range of forward and backward movement of the stem in the axial direction.

6. A needle valve according to claim 1, further comprising a bonnet that houses the stem, a valve seat member that is fitted and attached to the valve body to which the bonnet is attached, and a valve seat retaining spacer that is interposed between the bonnet and the valve seat member to retain the valve seat member.

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