Gate valve

Abstract

To provide a gate valve enabling an operator to easily recognize the number of revolutions of a valve stem.SOLUTION: A gate valve 1 includes a valve stem 2 to which a valve element 3 is mounted via a screw mechanism 4, and a housing 10 supporting the valve stem 2. The gate valve 1 further includes ball plungers 11, 12 held by the housing 10. In the outer periphery of the valve stem 2, latching recessed portions 37(1)-37(4) are provided to which balls 11a, 12a of the ball plungers 11, 12 can be latched. Each time the ball plungers 11, 12 are latched to the latching recessed portions 37(1)-37(4), an operator for the gate valve 1 can get click feelings due to latching. Thus, the operator can recognize the number of revolutions of the valve stem 2 at which the valve stem 2 is rotated, from the frequency of the click feelings.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a gate valve that stops water flow by moving a valve element through rotation of a valve stem. [Background technology]

[0002] Such a gate valve is described in Patent Document 1. The gate valve in this document has a valve disc and a valve stem. The valve disc is attached to the valve stem via a screw mechanism. The screw mechanism includes a male thread on the valve stem and a female thread on the valve disc. The gate valve also has a housing including a valve chamber in which the valve disc is housed, a flow path passing through the valve chamber, a support part that rotatably supports the valve stem outside the valve chamber, and a guide that prevents the valve disc from rotating together with the valve stem. The guide is provided within the valve chamber. When the valve stem is rotated, the valve disc moves along the axis of the valve stem between an open position that opens the flow path and a closed position that closes the flow path. In the open position, the valve disc is separated from the bottom of the valve chamber. In the closed position, the valve disc abuts against the bottom of the valve chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-200031 Summary of the Invention [Problem to be solved by the invention]

[0004] In a gate valve, the position of the valve disc within the valve chamber cannot be determined from the outside. Therefore, when moving the valve disc from the open position to the closed position to close the flow path, the operator may rotate the valve stem excessively. If the valve disc abuts against the bottom of the valve chamber and is unable to move, rotating the valve stem excessively may damage the valve stem, valve disc, or screw mechanism. If the valve stem, valve disc, or screw mechanism is damaged, the gate valve will no longer be able to stop water flow.

[0005] In view of the above, an object of the present invention is to provide a gate valve that allows an operator to easily grasp the number of rotations of the valve stem. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a gate valve comprising: a valve stem; a valve disc attached to the valve stem via a screw mechanism and movable along the axis of the valve stem; a valve chamber in which the valve disc is accommodated; a flow path passing through the valve chamber; an annular support part that rotatably supports the valve stem from the outside in the radial direction outside the valve chamber; and a rotation restricting part that restricts the valve disc from rotating together with the valve stem, wherein the valve disc moves between an open position that opens the flow path and a closed position that closes the flow path by rotation of the valve stem, and wherein the valve disc is provided with a ball plunger. an O-ring sealing between the valve stem and the support; The support portion includes a holding portion that holds the ball plunger in a position where the ball protrudes into a center hole of the support portion, and the valve stem includes a locking recess in which the ball can be locked, on the outer peripheral surface of a supported portion located on the inner peripheral side of the support portion. and a protruding portion protruding into the valve chamber, the supported portion, and an exposed portion exposed to the outside of the housing, in this order along the axis, and the supporting portion has an annular inner peripheral surface facing the protruding portion from the radially outer side relative to the locking recess in the supported portion, and the O-ring is held in an annular groove provided in the annular inner peripheral surface. A gate valve characterized by:

[0007] The gate valve of the present invention holds a ball plunger in a housing and has a locking recess on the outer surface of the valve stem, into which the ball of the ball plunger can be locked. Therefore, an operator of the gate valve who rotates the valve stem can feel a clicking sensation each time the ball plunger locks into the locking recess. Therefore, the operator can determine the number of rotations of the valve stem based on the number of clicks felt. This allows the operator to avoid rotating the valve stem excessively. Furthermore, the operator can stop the valve disc at a predetermined position between the open and closed positions based on the number of clicks felt. This allows the operator to set the gate valve to a predetermined opening degree and the water flow rate passing through the gate valve to a predetermined flow rate. Furthermore, if the operator stops operating the valve stem when they feel a clicking sensation, the ball plunger will be locked into the locking recess on the valve stem. Therefore, when water is flowing through the gate valve at a predetermined flow rate, the valve stem can be prevented or suppressed from rotating due to the pressure of water flowing through the valve chamber. This prevents the valve disc from moving, making it possible to maintain water flow at a predetermined flow rate. This becomes: The O-ring seals the gap between the valve stem and the support part of the housing at a position closer to the valve chamber than the locking recess. Therefore, even if the valve stem has a locking recess on its outer circumferential surface, water passing through the valve chamber can be prevented from leaking out of the housing through the gap between the valve stem and the housing. Furthermore, the ball plunger can be replaced while the gate valve is still in a water-passing state.

[0008] In the present invention, the ball plungers may include a first ball plunger and a second ball plunger, the support portion may include a first retaining portion that retains the first ball plunger and a second retaining portion that retains the second ball plunger, the valve stem may include a plurality of locking recesses, and the first ball plunger and the second ball plunger may simultaneously lock into two of the plurality of locking recesses. In this way, the two ball plungers simultaneously lock into two locking recesses, making it easy for the operator to feel a click. Furthermore, because the two ball plungers lock onto the valve stem, it is easy to prevent the valve stem from rotating due to the pressure of water flowing through the valve chamber when water is flowing through the valve disc positioned at a predetermined position between the open position and the closed position.

[0009] In the present invention, the first ball plunger and the second ball plunger may face each other across the valve stem, and the valve stem may include, as the locking recesses, a first locking recess and a second locking recess provided at an angular interval of 180° around the axis of the valve stem. This allows the two ball plungers to be locked to the valve stem from both sides in a direction perpendicular to the axis of the valve stem. This also allows the operator to feel a click every time the valve stem is rotated 180°.

[0010] In the present invention, the valve stem may include a third locking recess and a fourth locking recess as the locking recesses, and the first locking recess, the third locking recess, the second locking recess, and the fourth locking recess may be arranged at equal angular intervals in this order circumferentially. This allows the operator to feel a click every time the valve stem is rotated 90°. Furthermore, this allows for more precise adjustment of the gate valve opening compared to when there are two locking recesses.

[0011] In the present invention, the retaining portion may be a through hole that penetrates the support portion radially and communicates with the central hole, the through hole having an internal thread on its inner peripheral surface, and the ball plunger having an external thread that engages with the internal thread and is screwed into the through hole from the radially outer side. In this manner, the ball plunger held in the retaining portion can be moved radially by rotating it. Therefore, the pressure with which the ball protruding into the central hole of the support portion presses against the valve stem can be adjusted. This makes it easier to prevent the valve stem from rotating due to the pressure of water flowing through the valve chamber. [Effects of the Invention]

[0013] According to the present invention, when the valve stem rotates by a predetermined angle, a clicking sensation is transmitted to the operator. Therefore, the operator can easily grasp the number of rotations of the valve stem, and this can prevent or suppress the operator from rotating the valve stem excessively when moving the valve disc from the open position to the closed position to close the flow path. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a partial cross-sectional view of a gate valve with a valve body in an open position, viewed from a direction perpendicular to the flow path. [Figure 2] 3 is a partial cross-sectional view of a gate valve with a valve body in an open position, viewed from a direction along the flow path. FIG. [Figure 3] FIG. 4 is a partially enlarged view of the periphery of the support portion of the housing and the supported portion of the valve stem. [Figure 4] FIG. 10 is an explanatory diagram showing a state in which the annular member is removed from the housing main body. [Figure 5] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 6] 1 is a partial cross-sectional view of a gate valve with a valve body disposed in a closed position, viewed from a direction perpendicular to the flow path. [Figure 7] 3 is a partial cross-sectional view of a gate valve with a valve element disposed in a closed position, as viewed from a direction along the flow path. FIG. [Figure 8] 1 is a partial cross-sectional view of a gate valve with a valve body disposed in a predetermined position, viewed from a direction perpendicular to the flow path. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gate valve according to an embodiment of the present invention will be described below with reference to the drawings.

[0016] Figure 1 is a partial cross-sectional view of a gate valve with its valve disc in the open position, viewed from a direction perpendicular to the flow path. Figure 3 is a partial cross-sectional view of a gate valve with its valve disc in the open position, viewed from a direction along the flow path. Figure 4 is a partial cross-sectional view of a gate valve with its valve disc in the closed position, viewed from a direction perpendicular to the flow path. Figure 4 is a partial cross-sectional view of a gate valve with its valve disc in the closed position, viewed from a direction along the flow path. Figure 5 is a cross-sectional view taken along line AA in Figure 1.

[0017] As shown in FIG. 1, the gate valve 1 of this example has a valve stem 2 and a valve disc 3. The valve disc 3 is attached to the valve stem 2 via a screw mechanism 4. The valve disc 3 is movable along the axis L of the valve stem 2. The gate valve 1 also has a housing 10 that includes a valve chamber 5 in which the valve disc 3 is housed, a flow path 6 that passes through the valve chamber 5, an annular support portion 7 that rotatably supports the valve stem 2 from the radially outer side outside the valve chamber 5, and a rotation restricting portion 8 that restricts the valve disc 3 from rotating together with the valve stem 2. The flow path 6 extends in a direction perpendicular to the axis L of the valve stem 2. A first ball plunger 11 and a second ball plunger 12 (see FIG. 5) are held in the housing 10.

[0018] (Stem and disc) As shown in Figures 1 and 2, the valve stem 2 includes a protruding portion 21 that protrudes into the valve chamber 5, a supported portion 22 located on the inner periphery of the support portion 7, and an exposed portion 23 that is exposed outside the housing 10, in this order along the axis L. The protruding portion 21 is provided with a male thread 21a. In the following description, the direction along the axis L of the valve stem 2 is referred to as the axial direction X. The side on which the exposed portion 23 is located is referred to as the first direction X1 of the axial direction X, and the side on which the protruding portion 21 is located is referred to as the second direction X2 of the axial direction X. The second direction X is the side on which the flow path 6 is located in the housing 10. The direction in which the flow path 6 extends is referred to as the extension direction Y. The axial direction X and the extension direction Y are perpendicular to each other. The direction perpendicular to the axial direction X and the extension direction Y is referred to as the orthogonal direction Z.

[0019] Here, the valve element 3 includes a closing portion 25 that closes the flow path 6, an extension portion 26 that extends from the closing portion 25 in the first direction X1, and an axial hole 27 that penetrates the closing portion 25 and the extension portion 26 in the axial direction X. An internal thread 27a is provided on the inner peripheral surface of the axial hole 27 in the extension portion 26. The valve element 3 is configured such that the valve stem 2 is inserted through the axial hole 27 and the internal thread 27a is screwed onto the external thread 21a of the protruding portion 21. The valve body 3 is attached to the valve stem 2 in this state. The male thread 21a and the female thread 27a form the screw mechanism 4. The outer peripheral surface of the valve body 3 is covered with a sealing material .

[0020] The supported portion 22 of the valve stem 2 includes a shaft portion 31 and a flange portion 32 extending radially outward from the middle of the shaft portion 31. As shown in FIG. 3, the shaft portion 31 includes a first shaft portion 33 (shaft portion) located in the first direction X1 of the flange portion 32 and a second shaft portion 34 located in the second direction X2 of the flange portion 32. The first shaft portion 33 includes, from the flange portion 32 toward the first direction X1, a large diameter portion 35 having a constant outer diameter and a small diameter portion 36 having an outer diameter smaller than that of the large diameter portion 35, in this order. As shown in FIG. 5, the small diameter portion 36 is provided with a first locking recess 37(1) and a second locking recess 37(2) at positions spaced 180° apart in the circumferential direction. A third locking recess 37(3) and a fourth locking recess 37(4) are provided at the circumferential centers of the first locking recess 37(1) and the second locking recess 37(2). Therefore, the locking recesses 37(1) to 37(4) are provided around the axis L at equal angular intervals.

[0021] The outer diameter of the exposed portion 23 is equal to or smaller than the outer diameter of the small diameter portion 36. A handle 39 is detachably attached to the end of the exposed portion 23 in the first direction X1.

[0022] (housing) As shown in FIGS. 1 and 2 , the flow path 6 is provided at an end portion of the housing 10 in the second direction X2. The valve chamber 5 extends in the first direction X1 from a position overlapping with the flow path 6. The support portion 7 is provided in the first direction X1 of the valve chamber 5. As shown in FIG. 3 , the support portion 7 includes a first annular inner circumferential surface 41 facing the first shaft portion 33 of the shaft portion 31 from the radially outer side, a second annular inner circumferential surface 42 facing the flange portion 32 from the radially outer side in the second direction X2 of the first annular inner circumferential surface 41, and a third annular inner circumferential surface 43 facing the second shaft portion 34 of the shaft portion 31 from the radially outer side in the second direction X2 of the second annular inner circumferential surface 42. The first annular inner circumferential surface 41, the second annular inner circumferential surface 42, and the third annular inner circumferential surface 43 are coaxial. The support portion 7 also includes a first opposing surface 44 that faces the flange portion 32 from the first direction X1 side, and a second opposing surface 45 that faces the flange portion 32 from the second direction X2 side. The first opposing surface 44 restricts movement of the valve stem 2 in the first direction X1. The second opposing surface 45 restricts movement of the valve stem 2 in the second direction X2.

[0023] Furthermore, the support portion 7 is provided with a first retaining portion 47 that retains the first ball plunger 11 and a second retaining portion 48 that retains the second ball plunger 12 at its end portions in the first direction X1. The first retaining portion 47 and the second retaining portion 48 are each a through hole that passes through the support portion 7 in the radial direction. In this example, the first retaining portion 47 and the second retaining portion 48 are provided at angular positions that are 180° apart. Female threads 47a and 48a are provided on the inner circumferential surfaces of the first retaining portion 47 and the second retaining portion 48, respectively.

[0024] The first annular inner circumferential surface 41 includes a large-diameter inner circumferential surface portion 51 (inner circumferential surface portion) that faces the large-diameter portion 35 of the first shaft portion 33 from the radially outer side, and a small-diameter inner circumferential surface portion 52 that faces the small-diameter portion 36 of the first shaft portion 33 from the radially outer side in the first direction X1 of the large-diameter inner circumferential surface portion 51. The large-diameter inner circumferential surface portion 51 is provided with two annular grooves 53, 54 that are spaced apart in the axial direction X. The annular groove 54 is located in the second direction X2 of the annular groove 53. An O-ring 55 is held in the annular groove 54. An O-ring 56 is held in the annular groove 54. The O-rings 55, 56 provide a seal between the support portion 7 of the housing 10 and the large-diameter portion 35 of the first shaft portion 33 of the valve stem 2.

[0025] An opening on the inner periphery side of the first retaining portion 47 and an opening on the inner periphery side of the second retaining portion 48 are exposed in the small diameter inner periphery portion 52. As shown in FIG. 5, the first retaining portion 47 holds the first ball plunger 11 in a position where the ball 11a protrudes from the opening into the central hole of the support portion 7. The second retaining portion 48 holds the second ball plunger 12 in a position where the ball 12a protrudes from the opening into the central hole of the support portion 7. Here, the first ball plunger 11 has a female thread 47a threaded on its outer periphery. The second ball plunger 12 has an external thread 12b on its outer circumferential surface that can be threaded into the female thread 48a. The ball plungers 11, 12 are fixed to the support part 7 by being screwed into the respective holding parts 47, 48 from the radially outer side.

[0026] Additionally, an annular groove 58 is provided in the small diameter inner circumferential surface portion 52 in the first direction X1 between the opening of the first retaining portion 47 and the opening of the second retaining portion 48. An O-ring 59 is held in the annular groove 58. The O-ring 59 seals the gap between the small diameter inner circumferential surface portion 52 of the support portion 7 and a portion of the small diameter portion 36 of the valve stem 2 that is closer to the first direction X1 than the locking recesses 37(1) to 37(4).

[0027] The second annular inner circumferential surface 42, which faces the flange portion 32, has a larger inner diameter than the first annular inner circumferential surface 41 and the third annular inner circumferential surface 43. A large-diameter annular groove 61 is provided in the second annular inner circumferential surface 42. A large-diameter O-ring 62 is retained in the large-diameter annular groove 61. The large-diameter annular groove 61 is wider in the axial direction X and deeper in the radial direction than the annular grooves 53, 54 provided in the first annular inner circumferential surface 41. The large-diameter O-ring 62 has a larger inner diameter than the O-rings 55, 56 and is thicker in the axial direction X and radial directions than the O-rings 55, 56. The large-diameter O-ring 62 radially seals the gap between the flange portion 32 of the valve stem 2 and the support portion 7 of the housing 10.

[0028] The rotation restricting portion 8 is a protrusion provided on the inner wall surface of the valve chamber 5 in the housing 10. The rotation restricting portion 8 contacts both end edges of the valve element 3 in the orthogonal direction Z, restricting the valve element 3 from rotating together with the valve stem 2. Therefore, when the valve stem 2 rotates, the valve element 3 moves in the axial direction X of the valve stem 2.

[0029] 1 and 2, the housing 10 includes a housing main body 65 having therein a flow path 6, a valve chamber 5, and a rotation restricting portion 8, and an annular member 66 detachably attached to the housing main body 65. The valve stem 2 passes through a central hole of the annular member 66.

[0030] The housing main body 65 also includes a main body member 67 having the flow path 6, and a lid member 68 that covers the main body member 67 from the side in the first direction X1. The lid member 68 is fastened to the main body member 67 with four bolts 69. A valve chamber 5 is defined between the main body member 67 and the lid member 68.

[0031] As shown in Fig. 4, the cover member 68 has a cylindrical portion 71 at an end portion in the first direction X1. The cylindrical portion 71 opens in the first direction X1. An annular notched groove 72 is provided at the edge of the opening of the cylindrical portion 71. An internal thread 71a is provided on the inner peripheral surface of the cylindrical portion 71 in the second direction X2 of the notched groove 72.

[0032] As shown in FIGS. 4 and 5 , the annular member 66 includes a plate portion 75 having a substantially hexagonal outline when viewed from the axial direction X, a substantially rectangular parallelepiped protruding portion 76 protruding in the first direction X1 from the center of the plate portion 75, and a cylindrical portion 77 protruding in the second direction X2 from the plate portion 75. The cylindrical portion 77 includes an external thread 77a on its outer circumferential surface that is threadedly engaged with an internal thread 71a of the tubular portion 71 of the cover member 68. The cylindrical portion 77 also includes an annular groove 74 on its outer circumferential surface, extending in the first direction X1 from the external thread 77a. The annular groove 74 is located between the external thread 77a and the plate portion 75. The annular groove 74 protrudes radially outward from a position adjacent to the plate portion 75 in the second direction X2. An O-ring 73 (fourth O-ring) is attached to the annular groove 74.

[0033] The protruding portion 76 is provided with a first retaining portion 47 and a second retaining portion 48 on either side of the center hole of the annular member 66. The first ball plunger 11 is screwed into the first retaining portion 47 from one side in the extension direction Y. The second ball plunger 12 is screwed into the second retaining portion 48 from the other side in the extension direction Y.

[0034] The annular member 66 is attached to the housing main body 65 by screwing the cylindrical portion 77 into the tubular portion 71 from the side in the first direction X1. In this example, when the cylindrical portion 77 is attached to the housing main body 65, the longitudinal direction of the protruding portion 76 faces the extension direction Y of the flow path 6. When the annular member 66 is attached to the housing main body 65, the longitudinal direction of the protruding portion 76 may face in a direction different from the extension direction Y. Here, when the annular member 66 is fixed to the cover member 68, the O-ring 73 attached to the annular groove 74 of the annular member 66 is interposed between the tubular portion 71 and the cylindrical portion 77 with its outer periphery inserted into the cutout groove 72 of the tubular portion 71. In this way, the O-ring 73 seals the gap between the annular member 66 and the cover member 68. Furthermore, when the annular member 66 is fixed to the lid member 68, the plate portion 75 located adjacent to the annular groove 74 in the first direction X1 covers the cylindrical portion 77 from the first direction X1 side and comes into contact with the cylindrical portion 77. As a result, the O-ring 73 abuts against the plate portion 75 and is elastically deformed, thereby sealing the gap between the plate portion 75 and the lid member 68.

[0035] The annular member 66 is fixed to the cover member 68 by a fixing screw 79 (see FIG. 2) that penetrates the plate portion 75 in the axial direction X and is screwed into the end face of the cylindrical portion 71 in the first direction X1.

[0036] Here, the support portion 7 of the housing 10 is composed of a cover member 68 and an annular member 66. That is, the cover member 68 has a second annular inner circumferential surface 42, a third annular inner circumferential surface 43, and a second opposing surface 45. The annular member 66 has a first retaining portion 47, a second retaining portion 48, a first annular inner circumferential surface 41, and a first opposing surface 44.

[0037] (Opening and closing of gate valve) Figure 6 is a partial cross-sectional view of the gate valve 1 with the valve element 3 in the open position, viewed from a direction perpendicular to the flow path 6. Figure 7 is a partial cross-sectional view of the gate valve 1 with the valve element 3 in the open position, viewed from a direction along the flow path 6. Figure 8 is a partial cross-sectional view of the gate valve 1 with the valve element 3 in a predetermined position, viewed from a direction perpendicular to the flow path 6. The gate valve 1 is installed in the middle of a pipe through which water flows. In this example, it is installed in the middle of a fire protection pipe that distributes water stored in a fire water tank.

[0038] When an operator operates the handle 39 to rotate the valve stem 2, the valve disc 3 moves along the axis L of the valve stem 2 between an open position 3A (see Figures 1 and 3), in which the flow path 6 is open, and a closed position 3B (see Figures 6 and 7), in which the flow path 6 is closed. In the open position 3A, the valve disc 3 moves away from the bottom 5a of the valve chamber 5 in the first direction X1 and abuts against the ceiling 5b of the valve chamber 5. This puts the gate valve 1 into a water-permeable state, allowing water to flow through the piping. In the closed position 3B, the valve disc 3 abuts against the bottom 5a of the valve chamber 5. This puts the gate valve 1 into a water-stopping state, cutting off water flow through the piping.

[0039] Here, with the gate valve 1, the position of the valve disc 3 in the valve chamber 5 cannot be determined from the outside. Therefore, when moving the valve disc 3 from the open position 3A to the closed position 3B to close the flow path 6, the operator may rotate the valve stem 2 excessively. If the valve stem 2 is rotated excessively when the valve disc 3 abuts against the bottom 5a of the valve chamber 5 and is unable to move, the valve stem 2, valve disc 3, or screw mechanism 4 may be damaged. If the valve stem 2, valve disc 3, or screw mechanism 4 is damaged, the gate valve 1 will no longer be able to stop water flow.

[0040] To address this problem, the gate valve 1 of this example has a first ball plunger 11 and a second ball plunger 12. The support portion 7 of the housing 10 has a first retaining portion 47 that retains the first ball plunger 11 and a second retaining portion 48 that retains the second ball plunger 12. The valve stem 2 has four locking recesses 37(1) to 37(4) on its outer circumferential surface. The first ball plunger 11 and the second ball plunger 12 simultaneously lock into two of the four locking recesses 37(1) to 37(4). Therefore, the operator feels a clicking sensation each time the ball plungers 11 and 12 lock into the locking recesses 37(1) to 37(4). Therefore, the operator can grasp the number of rotations of the valve stem 2 from the number of clicks he or she feels. Therefore, the operator can avoid excessive rotation of the valve stem 2 after the valve disc 3 is placed in the closed position 3B, which may result in damage to the valve stem 2, the valve disc 3, or the screw mechanism 4.

[0041] Furthermore, the operator can stop the valve disc 3 at a predetermined position C between the open position 3A and the closed position 3B based on the number of clicks he or she feels. The state shown in Figure 8 is when the operator stops the rotation of the valve stem 2 from the state where the valve disc 3 is in the open position 3A when he or she feels a predetermined number of clicks, and the valve disc 3 is at the predetermined position C.

[0042] According to this example, the valve element 3 can be placed in a predetermined position 3C without relying on the sense of the operator operating the gate valve 1. Therefore, even if the operator is different, the valve element can be placed in the predetermined position 3C. This allows the opening degree of the gate valve 1 to be set to a predetermined opening degree, so that the flow rate of water passing through the gate valve 1 can be set to a predetermined flow rate.

[0043] Furthermore, if the operator stops operating the valve stem 2 when he or she feels a click, each of the ball plungers 11, 12 will be locked into two of the locking recesses 37(1) to 37(4) of the valve stem 2. Therefore, when water is passing through the gate valve 1 at a predetermined flow rate, rotation of the valve stem 2 due to the pressure of the water flowing through the valve chamber 5 can be prevented or suppressed. This prevents the valve element 3 from moving, making it possible to maintain water flow at a predetermined flow rate.

[0044] In this example, the first ball plunger 11 and the second ball plunger 12 face each other across the valve stem 2. The valve stem 2 has locking recesses 37(1) to 37(4) that are provided at equal angular intervals. Therefore, the operator can feel a click every time the valve stem 2 is rotated by 90°. Therefore, the opening degree of the gate valve 1 can be adjusted more finely than when, for example, the valve stem 2 is provided with two locking recesses 37.

[0045] Furthermore, in this example, the retaining portions 47, 48 that hold the ball plungers 11, 12 are through-holes that penetrate the support portion 7 radially and communicate with the central hole. Female threads 47a, 48a are provided on the inner circumferential surfaces of the through-holes. The ball plungers 11, 12 have male threads 11b, 12b that screw into the female threads 47a, 48a and are screwed into the retaining portions 47, 48 from the radial outside. Therefore, by rotating the ball plungers 11, 12 held by the retaining portions 47, 48, the ball plungers 11, 12 can be moved radially. This allows the pressure with which the balls 11a, 12a protruding into the central hole of the support portion 7 press against the valve stem 2 to be adjusted. This makes it easier to prevent the valve stem 2 from rotating due to the pressure of water flowing through the valve chamber 5.

[0046] In this example, O-rings 55 and 56 are provided to seal between the valve stem 2 and the support portion 7. The valve stem 2 includes a protruding portion 21 that protrudes into the valve chamber 5, a supported portion 22, and an exposed portion 23 that is exposed outside the housing 10, in this order along the axis L. The housing 10 includes a first annular inner circumferential surface 41 that faces radially outward in the X2 direction relative to the locking recesses 37(1) to 37(4) of the supported portion 22. The O-rings 55 and 56 are held in annular grooves 53 and 54 provided in the first annular inner circumferential surface 41. As a result, the O-rings 55 and 56 seal between the valve stem 2 and the housing 10 at positions closer to the valve chamber 5 than the locking recesses 37(1) to 37(4) of the valve stem 2. Therefore, even if the valve stem 2 has the locking recesses 37(1) to 37(4) on its outer circumferential surface, water passing through the valve chamber 5 can be prevented from leaking out of the housing 10 through the gap between the valve stem 2 and the housing 10. Furthermore, even if the ball plungers 11, 12 are removed from the retaining portions 47, 48, water will not leak from between the valve stem 2 and the housing 10. Therefore, when replacement of the ball plungers 11, 12 becomes necessary, the replacement work can be performed while the gate valve 1 is still in a water-passing state.

[0047] (Variation) Four or more locking recesses 37 may be provided. Even in this case, it is desirable that the first ball plunger 11 and the second ball plunger 12 are simultaneously locked in two of the four or more locking recesses 37. The gate valve 1 may also be provided with only one of the first ball plunger 11 and the second ball plunger 12. In this case, one or more locking recesses 37 are provided. [Explanation of symbols]

[0048] 1...gate valve, 2...valve stem, 3...valve disc, 3A...open position, 3B...closed position, 4...screw mechanism, 5...valve chamber, 5a...bottom of valve chamber, 5b...ceiling of valve chamber, 6...flow path, 7...support portion, 7a...center hole of support portion, 8...rotation restricting portion, 10...housing, 11...first ball plunger, 11a...ball, 12...second ball plunger, 12a...ball, 21...protruding portion, 22...supported portion, 23...exposed portion, 25...closing portion, 26...extension portion, 27...shaft hole, 28...sealing material, 31...shaft portion, 32...flange portion, 33...first shaft portion, 34...second shaft portion, 35...large diameter portion, 36...small diameter portion, 37...engaging recess, 39...handle, 41...first annular inner circumferential surface, 42...second Second annular inner peripheral surface, 43...third annular inner peripheral surface, 44...first opposing surface, 45...second opposing surface, 47...first retaining portion, 48...second retaining portion, 51...large diameter inner peripheral surface portion, 52...small diameter inner peripheral surface portion, 53...annular groove, 54...annular groove, 55...O-ring, 56...O-ring, 58...annular groove, 59...O-ring, 61...large diameter annular groove, 62...large diameter O-ring, 65...housing body, 66...annular member, 66a...center hole of annular member, 67...main body member, 68...cover member, 69...bolt, 71...cylindrical portion, 72...notched groove, 73...O-ring, 74...annular groove, 75...plate portion, 76...projecting portion, 77...cylindrical portion, L...axis of valve stem, X...axial direction, Y...extension direction of flow path, Z...orthogonal direction

Claims

1. a valve stem; a valve disc attached to the valve stem via a screw mechanism and movable along the axis of the valve stem; a valve chamber accommodating the valve disc; a flow path passing through the valve chamber; an annular support portion rotatably supporting the valve stem from the outside in the radial direction outside the valve chamber; and a rotation restricting portion restricting the valve disc from rotating together with the valve stem, wherein the valve disc moves between an open position that opens the flow path and a closed position that closes the flow path in response to rotation of the valve stem, A ball plunger; an O-ring sealing between the valve stem and the support portion; the support portion includes a holding portion that holds the ball plunger in an orientation in which the ball protrudes into a center hole of the support portion, the valve stem has an outer peripheral surface of a supported portion located on the inner peripheral side of the support portion, a locking recess in which the ball can be locked, and the valve stem also has, in this order along the axis, a protruding portion that protrudes into the valve chamber, the supported portion, and an exposed portion that is exposed to the outside of the housing, Furthermore, the support portion includes an annular inner circumferential surface that faces the protruding portion from the radially outer side relative to the locking recess in the supported portion, A gate valve characterized in that the O-ring is held in an annular groove provided on the annular inner surface.

2. The ball plunger includes a first ball plunger and a second ball plunger, the support portion includes, as the holding portion, a first holding portion that holds the first ball plunger and a second holding portion that holds the second ball plunger, The valve stem includes a plurality of the locking recesses, 2. The gate valve according to claim 1, wherein the first ball plunger and the second ball plunger are simultaneously engaged with two of the plurality of engaging recesses.

3. The first ball plunger and the second ball plunger face each other across the valve stem, 3. The gate valve according to claim 2, wherein the valve stem has, as the locking recesses, a first locking recess and a second locking recess provided at an angular interval of 180° around the axis of the valve stem. 。

4. The valve stem includes a third locking recess and a fourth locking recess as the locking recess, The gate valve according to claim 3, characterized in that the first locking recess, the third locking recess, the second locking recess, and the fourth locking recess are arranged in this order circumferentially at equal angular intervals.

5. the holding portion is a through hole that penetrates the support portion in a radial direction and communicates with the center hole, An internal thread is provided on the inner peripheral surface of the through hole, 5. A gate valve according to claim 1, wherein the ball plunger has a male thread that is threaded into the female thread and is screwed into the through hole from the outside in the radial direction.

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