Water leakage prevention device of valve, valve, and water leakage prevention method of valve

Abstract

To provide a water leakage prevention device which can be attached to a shaft seal part of a valve even if a work space is narrow.SOLUTION: A water leakage prevention device 100 prevents water leakage from a shaft seal part 20 of a valve 1 and includes: an annular second seal member 32 which closes a space between an outer peripheral surface of a valve rod 3 and a first through hole 15 of a pressing member 7; a holding member 33 which holds the second seal member 32; and a plurality of rotatable pressing bodies 101 which press the holding member 33 against the pressing member 7. The holding member 33 has a plurality of split holding pieces which can be split; and holding piece joint members which join the split holding pieces to each other. The pressing body 101 is threadedly engaged with a bolt 8 through a screw 102 and has a plurality of split pressing pieces which may be split in a radial direction of the bolt 8; and pressing piece joint members which join the split pressing pieces to each other.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present invention relates to a water leakage prevention device that prevents water leakage from a shaft seal of a valve, a valve equipped with a water leakage prevention device, and a water leakage prevention method that prevents water leakage from a shaft seal of a valve. [Background technology]

[0002] Conventionally, as a water leakage prevention device for this type of valve, for example, there is a water leakage prevention device 203 for preventing water leakage from a shaft seal part 202 of a gate valve 201 as shown in Fig. 24. Also, Fig. 23 is a cross-sectional view of the shaft seal part 202 before the water leakage prevention device 203 is attached. As shown in Fig. 23, the shaft seal part 202 is provided with a plurality of annular gland packings 204 housed in a packing box 205. The packing box 205 is provided on the upper part of a valve box 206, and a valve stem 207 protrudes from the inside of the valve box 206 through the gland packing 204 to the outside and upward. The gland packing 204 seals the gap between the outer peripheral surface of the valve stem 207 and the inner peripheral surface of the packing box 205.

[0003] A packing gland 208 that presses the gland packing 204 from the outside is disposed above the packing box 205. The packing gland 208 is connected to the packing box 205 by a plurality of stud bolts 209 that are erected on the packing box 205 and first nuts 210 that screw onto the stud bolts 209. By tightening the first nuts 210, the packing gland 208 presses the gland packing 204 downward.

[0004] A first gear 211 is provided at the upper end of the valve stem 207. The first gear 211 meshes with a second gear 216, which is connected to a rotating handle (not shown) so as to be interlocked with the rotating handle. By turning the rotating handle, the first gear 211 and the second gear 216 rotate, and the valve stem 207 rotates and the valve body (not shown) is opened and closed. The first gear 211 is formed with a plurality of holes 212 that penetrate in the vertical direction. The holes 212 are disposed so as to be located directly above the stud bolt 209 and the first nut 210.

[0005] In such a check valve 201, due to deterioration of the gland packing 204 over time, etc., liquid (e.g., water) in the valve box 206 may pass between the outer surface of the valve stem 207 and the inner surface of the gland packing 204, and leak out from between the outer surface of the valve stem 207 and the inner surface of the packing gland 208 above the packing gland 208.

[0006] When the above-mentioned water leakage W occurs, the water leakage is prevented by using a water leakage prevention device 203 as shown in Fig. 24. The water leakage prevention device 203 has an O-ring 213 that is disposed on the outer circumferential surface of the valve stem 207 and closes the gap between the outer circumferential surface of the valve stem 207 and the inner circumferential surface of the packing gland 208, a case 214 that holds the O-ring 213, and a pressing plate 215 that presses the case 214. Case 214 has two split case pieces, and bolts 219 and nuts that join the split case pieces together.

[0007] An insertion hole 222 is formed in the holding plate 215, and the stud bolt 217 is inserted through the insertion hole 222. When installing the water leakage prevention device 203, the existing stud bolt 209 shown in Fig. 23 is not long enough, so another stud bolt 217 (see Fig. 24) longer than the existing stud bolt 209 is newly used. A second nut 218 is screwed onto these newly installed stud bolts 217, and by tightening the second nut 218, the holding plate 215 presses the case 214 downward, compressing the O-ring 213. The holding plate 215 has a split holding piece divided into two.

[0008] According to this, as shown in FIG. 24, by tightening the second nut 218, the pressing plate 215 presses the case 214 downward, the O-ring 213 is compressed, and the gap between the outer peripheral surface of the valve stem 207 and the inner peripheral surface of the packing retainer 208 is sealed by the O-ring 213, thereby preventing water leakage.

[0009] In addition, since the case 214 is divided into two separate case pieces and the holding plate 215 is divided into two separate holding pieces, the case 214 and the holding plate 215 can be assembled and attached from the radial direction (horizontal direction) of the valve stem 207. This allows the water leakage prevention device 203 to be installed even if the space 220 between the top and bottom of the packing gland 208 and the first gear 211 is narrow.

[0010] At this time, the existing stud bolt 209 shown in Fig. 23 is replaced with a new stud bolt 217 shown in Fig. 24, and a first nut 210 and a second nut 218 are screwed onto the new stud bolt 217. Such replacement of the stud bolts 209, 217 and screwing of the first and second nuts 210, 218 are performed from above the first gear 211 through the hole 212.

[0011] As a result, even if the space 220 between the top and bottom of the packing gland 208 and the first gear 211 is narrower than the length of the newly installed stud 217, the existing stud 209 (see FIG. 23) can be removed and replaced with the new stud 217 (see FIG. 24). Also, even if the space 221 between the top and bottom of the upper end of the new stud 217 and the first gear 211 is narrower than the height of the second nut 218, the second nut 218 can be screwed onto the new stud 217. The above-mentioned water leakage prevention device 203 is described in, for example, Patent Document 1 below. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent Publication No. 2022-166345 Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the above-mentioned conventional type, the replacement work of the stud bolts 209, 217 and the screwing work of the first and second nuts 209, 218 are performed from above the first gear 211 through the hole 212. However, if the hole 212 is not formed in the first gear 211 or the position of the hole 212 is radially shifted from directly above the existing stud bolt 209, unless a large working space is secured between the gasket retainer 208 and the first gear 211, it will be difficult to replace the stud bolts 209, 217 and screw the first and second nuts 209, 218, and there is a risk that the water leakage prevention device 203 cannot be attached to the shaft seal portion 202 of the check valve 201. An object of the present invention is to provide a water leakage prevention device, a valve, and a method for preventing water leakage from a valve that can be attached to a shaft seal portion of a valve even if the working space is narrow. [Means for solving the problem]

[0014] In order to achieve the above object, the first invention provides a valve valve having a valve stem penetrating a valve body, a first seal member for sealing the penetrating portion of the valve stem, a storage section for storing the first seal member, a pressing member for pressing the first seal member stored in the storage section from the outside toward the inside of the valve body in the axial direction, and a plurality of bolts for fixing the pressing member; The bolt is provided in the storage section, A first through hole is formed in the pressing member, A water leakage prevention device that prevents water leakage from a shaft seal of a valve in which a valve stem passes through a first through hole and a bolt passes through a pressing member, A second seal member having an annular shape is disposed on the outer circumferential surface of the valve rod to close a gap between the outer circumferential surface of the valve rod and the first through hole of the pressing member; a holding member for holding the second seal member; a plurality of rotatable pressing bodies for pressing the holding member against the pressing member; A second through hole is formed in the holding member, The valve stem passes through the second through hole; The retaining member has a plurality of divided retaining pieces that can be separated in a radial direction of the valve stem from the second through hole, and a retaining piece joining member that joins the divided retaining pieces together, The pressing body is screwed onto the bolt via a screw, and has a plurality of split pressing pieces that can be separated in the radial direction of the bolt, and a pressing piece joining member that joins the split pressing pieces together.

[0015] According to this, the second sealing member is placed on the outer peripheral surface of the valve rod, and the retaining member is assembled by joining multiple split retaining pieces together with a retaining piece joining member so as to surround the valve rod from the radial direction of the valve rod and so that the valve rod passes through the second through hole of the retaining member, and the second sealing member is held by the retaining member.

[0016] The pressing body is then assembled by joining the multiple split pressing pieces together with a pressing piece joining member while screwing them onto the bolts from the radial direction. The pressing body is then rotated and tightened onto the bolts, and the holding member is pressed against the pressing member by the pressing body. This compresses the second seal member, and the second seal member seals the gap between the outer circumferential surface of the valve stem and the first through hole of the pressing member, preventing water leakage from the shaft seal.

[0017] In this case, since the pressing body can be assembled by joining the multiple divided pressing pieces together from the radial direction of the bolt with the pressing piece joining member, even if the working space secured outside the valve body and outside the longitudinal direction of the bolt is narrow, the pressing body can be assembled and screwed onto the bolt. Therefore, even if the working space is narrow, the water leakage prevention device can be attached to the shaft seal of the valve.

[0018] In the water leakage prevention device according to the second invention, the pressing body has an extension member that is connected to the bolt via a screw, and a pressing part main body that is screwed into the extension member via a screw, The pressing portion main body presses the holding member against the pressing member, The extension member is rotatable relative to the bolt and has a plurality of split extension pieces that can be separated in the radial direction of the bolt, and an extension piece joining member that joins the split extension pieces together, The pressing portion main body is rotatable relative to the extension member and has a plurality of divided main body pieces that can be divided in the radial direction of the bolt, and a main body piece joining member that joins the divided main body pieces together, The split extension piece and the split main body piece constitute a split pressing piece, The extension piece joining member and the main body piece joining member constitute a pressure piece joining member.

[0019] According to this, a plurality of split extension pieces are joined together by an extension piece joining member in a state where the split extension pieces are screwed onto the bolt from the radial direction. In this way, the extension members are assembled and are joined to the bolt via the screws.

[0020] Furthermore, the divided body pieces are joined together by the body piece joining members while being screwed to the extension members from the radial direction, whereby the pressing portion body is assembled and screwed to the extension members via the screws.

[0021] The pressing part body is then rotated and tightened to the extension member, and the pressing part body presses the retaining member against the pressing member, compressing the second seal member and sealing the gap between the outer circumferential surface of the valve stem and the first through hole of the pressing member, thereby preventing water leakage from the shaft seal.

[0022] In this case, the extension member can be assembled by joining multiple split extension pieces together from the radial direction of the bolt with extension piece joining members, and the pressing portion main body can be assembled by joining multiple split main body pieces together from the radial direction of the bolt with main body piece joining members.Therefore, even if the working space secured outside the valve box and outside the bolt in the longitudinal direction is narrow, the pressing body can be assembled and screwed onto the bolt.

[0023] In addition, by extending the extension member to the bolt and screwing the pressing body onto the extension member, the pressing body can be connected to the bolt via the extension member even if the length of the bolt is insufficient. This allows the pressing body to be screwed onto the bolt and tightened, and the pressing body to press the holding member against the pressing member, even if the length of the bolt is insufficient.

[0024] In the water leakage prevention device according to the third invention, the retaining member comes into contact with the extension member in the rotational direction of the valve stem, thereby restricting the rotation of the retaining member. This makes it possible to prevent the retaining member from rotating (co-rotating) with the valve stem when the valve stem rotates.

[0025] In the fourth aspect of the present invention, the water leakage prevention device has an outer circumferential surface having a predetermined radius formed on the extension member, The extension piece joint member is contained inside the radius of the outer peripheral surface of the extension member. With this, the extension piece joining member does not protrude radially outward beyond the outer circumferential surface of the extension member, thereby preventing the extension piece joining member from interfering with the holding member.

[0026] The fifth invention is a valve equipped with the water leakage prevention device according to any one of the first to fourth inventions, A torque transmission member for transmitting a torque to the valve stem is provided on the valve stem outside the valve body, The water leakage prevention device is disposed between the pressing member and the rotational force transmission member.

[0027] The valve body is opened and closed by the rotation of the valve stem, and the torque is transmitted to the valve rod via the torque transmission member. Even if the space between the pressing member and the torque transmission member is narrow, the water leakage prevention device can be attached to the shaft seal of the valve.

[0028] The sixth invention is a method for preventing water leakage from a valve using the water leakage prevention device according to the first invention, a second seal member disposed on an outer peripheral surface of the valve stem; Assembling the retaining member by joining the divided retaining pieces together with a retaining piece joining member so as to surround the valve stem from a radial direction of the valve stem so that the valve stem passes through the second through hole of the retaining member; The second seal member is held by a holding member; The plurality of divided pressing pieces are screwed onto the bolts from the radial direction and joined together with a pressing piece joining member to assemble the pressing body; By turning the pressing body and tightening it onto the bolt, the retaining member is pressed against the pressing member, and the second seal member is pressed and compressed against the outer circumferential surface of the valve stem and the pressing member.

[0029] According to this, even if the working space secured outside the valve body and outside the bolt in the longitudinal direction is narrow, the pressing body can be assembled and screwed onto the bolt. Therefore, even if the working space is narrow, the water leakage prevention device can be attached to the shaft seal of the valve.

[0030] The method for preventing water leakage from a valve in the seventh invention involves wrapping a string-like second sealing member around the outer peripheral surface of the valve stem and bonding both ends to form it into a circular ring shape, and placing it on the outer peripheral surface of the valve stem.

[0031] With this, even if the working space secured outside the valve box and outside the longitudinal direction of the bolt is narrow, the second sealing member can be positioned on the outer peripheral surface of the valve rod to seal the space between the outer peripheral surface of the valve rod and the first through hole of the pressing member. Effect of the Invention

[0032] As described above, according to the present invention, since the pressing body can be assembled by joining the multiple divided pressing pieces together from the radial direction of the bolt with the pressing piece joining member, even if the working space secured outside the valve body and outside the longitudinal direction of the bolt is narrow, the pressing body can be assembled and screwed onto the bolt. Therefore, even if the working space is narrow, the water leakage prevention device can be attached to the shaft seal of the valve. [Brief description of the drawings]

[0033] [Figure 1] 2 is a cross-sectional view of a shaft seal portion of a gate valve before a water leakage prevention device in a first embodiment of the present invention is installed. FIG. [Diagram 2] 2 is a cross-sectional view taken along the line XX in FIG. [Diagram 3] FIG. 2 is a cross-sectional view of a shaft seal portion of a gate valve equipped with a water leakage prevention device according to the first embodiment. [Figure 4] FIG. 2 is an enlarged cross-sectional view of a portion of a shaft seal of a gate valve equipped with a water leakage prevention device according to the first embodiment. [Diagram 5] FIG. 2 is an oblique view of an O-ring and a retaining case of the water leakage prevention device of the first embodiment. [Figure 6]FIG. 4 is a cross-sectional view of an O-ring and a retaining case of the water leakage prevention device of the first embodiment. [Figure 7] FIG. 4 is an exploded perspective view of the holding case of the water leakage prevention device according to the first embodiment. [Figure 8] FIG. 2 is a perspective view of a joint member of the pressing body of the water leakage prevention device according to the first embodiment; [Figure 9] FIG. 11 is a plan view of the shaft seal portion of the gate valve with the O-ring, retaining case, and extension member of the water leakage prevention device attached. [Figure 10] FIG. 13 is an oblique view of the shaft seal portion of the gate valve to which the O-ring, retaining case, and extension member of the water leakage prevention device are attached. [Figure 11] FIG. 4 is an exploded perspective view of the extension member of the pressing body of the water leakage prevention device according to the first embodiment. [Figure 12] FIG. 4 is a perspective view of a pressing portion main body of the pressing body of the water leakage prevention device according to the first embodiment; [Figure 13] XX cross-sectional view of FIG. [Figure 14] FIG. 2 is an oblique view of the shaft seal of the gate valve equipped with the water leakage prevention device. [Figure 15] FIG. 4 is an exploded perspective view of a pressing portion main body of the water leakage prevention device according to the first embodiment. [Figure 16] FIG. 11 is a plan view of the shaft seal portion of the gate valve, showing the arrangement of the retaining case of the water leakage prevention device and the extension member of the pressing body. [Figure 17] FIG. 11 is a plan view of the shaft seal of the gate valve, showing the arrangement of the retaining case of the water leakage prevention device and the pressing portion main body of the pressing body. [Figure 18] 6 is a cross-sectional view of a shaft seal portion of a gate valve equipped with a water leakage prevention device in a second embodiment of the present invention. FIG. [Figure 19] 19 is a cross-sectional view taken along the line XX in FIG. 18. [Figure 20] FIG. 2 is an oblique view of the shaft seal of the gate valve equipped with the water leakage prevention device. [Figure 21] FIG. [Figure 22] FIG. 4 is an exploded perspective view of the pressing body of the water leakage prevention device according to the first embodiment; [Diagram 23] 1 is a cross-sectional view of a shaft seal portion of a gate valve before a conventional water leakage prevention device is installed. [Figure 24] FIG. 2 is a cross-sectional view of a shaft seal portion of a gate valve equipped with a water leakage prevention device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First embodiment)

[0035] In the first embodiment, as shown in Figures 1 and 2, 1 is an internally threaded gate valve, and the gate valve 1 has a valve box 2 that houses a valve body (not shown), a rotatable valve rod 3 that penetrates the inside and outside of the valve box 2, a gland packing 4 (an example of a first sealing member) that seals the penetration portion of the valve rod 3, a packing box 5 (an example of a storage section) in which the gland packing 4 is stored, a packing retainer 7 (an example of a retaining member) that presses the gland packing 4 downward from the outside (towards the inside of the valve box 2 in the axial direction 14), two (or more) stud bolts 8 (an example of bolts) that fix the packing retainer 7, and a large gear 9 (an example of a rotational force transmission member) that transmits the rotational force input from a rotating handle (not shown) to the valve rod 3.

[0036] The valve box 2 has a packing box 5 at its upper end, and the packing box 5 has a circular flange 5a at its upper end. The gland packing 4 is an annular packing, and multiple pieces of the gland packing 4 are stacked one on top of the other and stored in the packing box 5.

[0037] The stud bolt 8 is erected on the upper surface of the flange 5a of the packing box 5. The packing gland 7 has a cylindrical portion 12 that presses the gland packing 4 downward, and a flange portion 13 that extends laterally from one end of the cylindrical portion 12.

[0038] A first through hole 15 is formed in the center of the packing gland 7, penetrating in the axial direction 14 of the valve rod 3 (for example, the vertical direction in FIG. 1 ). A plurality of insertion holes 16 are formed in the flange portion 13, penetrating in the axial direction 14.

[0039] The valve stem 3 passes through a first through hole 15 of the packing gland 7, and the stud bolt 8 passes through an insertion hole 16 of the packing gland 7. A nut 18 is screwed onto the stud bolt 8. When the nut 18 is tightened, the packing gland 7 presses the gland packing 4 downward, thereby maintaining the watertightness of the shaft seal 20.

[0040] The large gear 9 meshes with the small gear 21, and is attached to the upper end of the valve stem 3 outside the valve box 2. The small gear 21 is provided so as to be interlocked with a rotating handle (not shown). When the rotating handle is turned, the small gear 21 and the large gear 9 rotate, and the rotational force is transmitted to the valve stem 3, which rotates and opens and closes the valve body.

[0041] Furthermore, the gap 19 between the tip of the stud bolt 8 and the large gear 9 is set to be narrower than the height H1 of the nut 18, so that the nut 18 cannot be turned and removed from the stud bolt 8.

[0042] In such a gate valve 1, the sealing performance between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the gland packing 4 may decrease due to aging of the gland packing 4, and liquid (e.g., fluid such as water) in the valve body 2 may pass between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the gland packing 4 and leak above the packing gland 7 from between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the packing gland 7. In order to prevent such leakage W from the shaft seal 20, a water leakage prevention device 31 as shown in FIG. 3 is attached to the shaft seal 20 and disposed between the packing gland 7 and the large gear 9.

[0043] As shown in Figures 3 and 4, the water leakage prevention device 31 has an annular O-ring 32 (an example of a second sealing member) that is arranged on the outer surface of the valve rod 3 and seals the space between the outer surface of the valve rod 3 and the first through hole 15 of the gasket 7, a retaining case 33 (an example of a retaining member) that holds the O-ring 32, and two (an example of multiple) rotatable pressing bodies 34 that press the retaining case 33 against the upper surface of the gasket 7. As shown in FIG. 5, the O-ring 32 is formed into a circular ring shape by bonding both ends of a string-like rubber (resin).

[0044] 4 to 6, the retaining case 33 is a rectangular flat plate-shaped member having a second through hole 37 at the center thereof penetrating in the axial direction 14 (vertical direction). The valve rod 3 passes through the second through hole 37.

[0045] A tapered surface 38 is formed around the entire circumference at the lower end of the second through hole 37. The tapered surface 38 expands in diameter downward and connects from the peripheral surface of the second through hole 37 to the lower surface of the retaining case 33. A triangular groove 39 is formed around the entire circumference by the outer circumferential surface of the valve rod 3 and the tapered surface 38, and the O-ring 32 is fitted into the triangular groove 39 and retained by the retaining case 33.

[0046] 7, the retaining case 33 has first and second split retaining pieces 41, 42 that can be separated in the radial direction 22 of the valve rod 3 from the second through hole 37, and two (multiple) sets of retaining piece joining members 43 that join these split retaining pieces 41, 42. The first and second split retaining pieces 41, 42 each have the second through hole 37 divided into two.

[0047] The retaining piece joining member 43 has a reamer bolt 44 and nuts 45 that can be screwed onto both ends of the reamer bolt 44. Two (plural) first bolt insertion holes 47 are formed in the first divided retaining piece 41, and two (plural) second bolt insertion holes 48 are formed in the second divided retaining piece 42. By inserting the reamer bolt 44 into the first and second bolt insertion holes 47, 48 and screwing and fastening the nuts 45 onto both ends of the reamer bolt 44, the first divided retaining piece 41 and the second divided retaining piece 42 are joined together as shown in FIG. 5, and the retaining case 33 is assembled.

[0048] As shown in Figures 3 and 4, the pressing body 34 has an extension member 52 that is extended to the stud bolt 8 via a female thread 51, and a pressing portion main body 56 that screws into the extension member 52 via a male thread 54 and a female thread 55.

[0049] 8, the extension member 52 has a cylindrical portion 58, a seat portion 59 provided at the lower end of the cylindrical portion 58, and a third through hole 60 passing through the cylindrical portion 58 and the seat portion 59 in the axial direction 14 (up-down direction). The female thread 51 is formed on the inner periphery of the cylindrical portion 58 and the seat portion 59. The male thread 54 is formed on the outer periphery of the cylindrical portion 58.

[0050] As shown in Fig. 9, the base portion 59 has an outer peripheral surface 62 having a predetermined radius R1. Recessed portions 63 that are recessed radially inwardly of the outer peripheral surface 62 are formed at multiple locations (four locations in Fig. 9) on the outer peripheral surface 62 of the base portion 59. As shown in Figs. 9 and 10, the holding case 33 is sandwiched between the base portions 59 of both extension members 52.

[0051] The extension member 52 is threadedly engaged with the stud bolt 8 and is freely rotatable, and as shown in Figure 11, has first and second split extension pieces 65, 66 that can be separated in the radial direction 23 of the stud bolt 8, and two sets (multiple sets) of extension piece joining members 67 that join the first and second split extension pieces 65, 66 to each other.

[0052] The extension piece joint member 67 has a reamer bolt 69 and nuts 70 that can be screwed onto both ends of the reamer bolt 69. Two (a plurality of) first bolt insertion holes 71 are formed in the first split extension piece 65, and two (a plurality of) second bolt insertion holes 72 are formed in the second split extension piece 66. The first and second bolt insertion holes 71, 72 open into a recessed portion 63 in the outer peripheral surface 62 of the base portion 59.

[0053] The reamer bolt 69 is inserted into the first and second bolt insertion holes 71, 72, and nuts 70 are screwed onto both ends of the reamer bolt 69 and tightened, thereby joining the first split extension piece 65 and the second split extension piece 66 as shown in Fig. 8, and assembling the extension member 52. At this time, both ends of the reamer bolt 69 and the nuts 70 are placed in the recessed portions 63 of the outer peripheral surface 62 of the base portion 59 and are contained inside the radius R1 of the outer peripheral surface 62 as shown in Fig. 9.

[0054] 12 and 13, the pressing portion body 56 has a fourth through hole 73 penetrating in the axial direction 14 (vertical direction) and an outer peripheral surface 74 having a predetermined radius R2. The female thread 55 is formed on the inner circumference of the pressing portion body 56. Recesses 75 recessed radially inwardly in the outer peripheral surface 74 are formed at multiple locations (four locations in FIG. 13).

[0055] As shown in Fig. 14, the pressing portion body 56 is screwed into the cylindrical portion 58 (see Fig. 8) of the extension member 52 and is rotatable, pressing the retaining case 33 against the upper surface of the packing gland 7. Also, as shown in Fig. 15, the pressing portion body 56 has first and second divided body pieces 77, 78 that can be separated in the radial direction 23 of the stud bolt 8, and two (multiple) sets of body piece joining members 79 that join the first and second divided body pieces 77, 78 together.

[0056] The main body piece joining member 79 has a reamer bolt 81 and nuts 82 that can be screwed onto both ends of the reamer bolt 81. Two (a plurality of) first bolt insertion holes 84 are formed in the first divided main body piece 77, and two (a plurality of) second bolt insertion holes 85 are formed in the second divided main body piece 78. The first and second bolt insertion holes 84, 85 open into the recessed portion 75 in the outer circumferential surface 74 of the pressing portion main body 56.

[0057] The reamer bolt 81 is inserted into the first and second bolt insertion holes 84, 85, and nuts 82 are screwed onto both ends of the reamer bolt 81 and tightened, thereby joining the first divided body piece 77 and the second divided body piece 78 as shown in Fig. 12, and assembling the pressing portion body 56. At this time, both ends of the reamer bolt 81 and the nuts 82 are placed in the recesses 75 of the outer circumferential surface 74 of the pressing portion body 56, and are contained inside the radius R2 of the outer circumferential surface 74, as shown in Fig. 13.

[0058] In the first embodiment, the first split extension piece 65 (see FIG. 11) and the first split main body piece 77 (see FIG. 15) form a first split pressing piece 89, and the second split extension piece 66 (see FIG. 11) and the second split main body piece 78 (see FIG. 15) form a second split pressing piece 90. Also, the extension piece joint member 67 (see FIG. 11) and the main body piece joint member 79 (see FIG. 15) form a pressing piece joint member 91. A method for preventing water leakage from the gate valve 1 using the water leakage prevention device 31 will be described below.

[0059] 1 is a diagram of the shaft seal portion 20 of the gate valve 1 without the water leakage prevention device 31. By turning the rotary handle, the rotational force is transmitted to the valve stem 3 via the small gear 21 and the large gear 9, causing the valve stem 3 to rotate and open / close the valve body.

[0060] Aging and deterioration of the gland packing 4 may cause the sealing performance between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the gland packing 4 to decrease, and water (liquid) in the valve box 2 may pass between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the gland packing 4, and leak out from between the outer circumferential surface of the valve stem 3 and the inner circumferential surface of the gland packing 7 above the gland packing 7. When such a water leakage W occurs, a water leakage prevention device 31 (see FIG. 3) is attached between the gland packing 7 and the large gear 9 as follows to prevent water leakage. First, the existing nut 18 (see FIG. 1) is loosened, and the nut 18 is split using a nut splitter to remove it from the stud bolt 8 .

[0061] Next, as shown in FIG. 11, the first split extension piece 65 and the second split extension piece 66 are screwed onto the stud bolt 8 from the radial direction 23 and joined with the extension piece joining member 67 to assemble the extension member 52.

[0062] At this time, the reamer bolt 69 of the extension piece joining member 67 is inserted into the first bolt insertion hole 71 and the second bolt insertion hole 72, and nuts 70 are screwed onto both ends of the reamer bolt 69 and tightened to join the first split extension piece 65 and the second split extension piece 66 as shown in Figures 8 to 10.

[0063] As a result, the male threads of the stud bolt 8 and the female threads 51 of the extension member 52 mesh with each other, and the extension member 52 is extended onto the upper end of the stud bolt 8, as shown in Figures 3, 4, and 10. The extension member 52 is then turned and tightened onto the stud bolt 8, so that the base portion 59 of the extension member 52 abuts against the upper surface of the packing gland 7.

[0064] 5, a string-like O-ring 32 (see phantom lines) is wound around the outer circumferential surface of the valve rod 3, and both ends are bonded to form an annular shape (see solid lines). As a result, the annular O-ring 32 is disposed on the outer circumferential surface of the valve rod 3, as shown in FIG.

[0065] Then, as shown in Figure 7, the first split retaining piece 41 and the second split retaining piece 42 are joined with a retaining piece joining member 43 from the radial direction 22 of the valve rod 3 so that the valve rod 3 passes through the second through hole 37 of the retaining case 33, and the retaining case 33 is assembled.

[0066] At this time, the reamer bolt 44 of the retaining piece joining member 43 is inserted into the first bolt insertion hole 47 and the second bolt insertion hole 48, and nuts 45 are screwed onto both ends of the reamer bolt 44 and tightened to join the first split retaining piece 41 and the second split retaining piece 42 as shown in Figure 5. Thereafter, as shown in FIGS. 4 and 6, the O-ring 32 is fitted into the triangular groove 39 and held in the holding case 33.

[0067] Furthermore, as shown in Figure 15, the first divided body piece 77 and the second divided body piece 78 are screwed into the cylindrical portion 58 of the extension member 52 from the radial direction 23, and then joined with a body piece joining member 79 to assemble the pressing portion body 56.

[0068] At this time, the reamer bolt 81 of the main body piece joining member 79 is inserted into the first bolt insertion hole 84 and the second bolt insertion hole 85, and nuts 82 are screwed onto both ends of the reamer bolt 81 and tightened to join the first split main body piece 77 and the second split main body piece 78 as shown in Figures 12 to 14.

[0069] As a result, the male thread 54 (see FIG. 8) of the extension member 52 and the female thread 55 (see FIG. 12) of the pressing portion main body 56 mesh with each other. Then, by turning the pressing portion main body 56 and tightening it into the extension member 52, the pressing portion main body 56 comes into contact with the upper surface of the retaining case 33 from above, as shown in FIGS. 3 and 4, and presses the retaining case 33 against the upper surface of the packing gland 7. As a result, the O-ring 32 is pressed against the outer circumferential surface of the valve stem 3 and the upper surface of the packing gland 7 and is compressed, and the gap between the outer circumferential surface of the valve stem 3 and the first through hole 15 of the packing gland 7 is blocked by the O-ring 32, thereby preventing water leakage W from the shaft seal portion 20.

[0070] In this case, as shown in Figure 11, the first split extension piece 65 and the second split extension piece 66 can be joined with an extension piece joining member 67 from the radial direction 23 of the stud bolt 8 to assemble the extension member 52, and as shown in Figure 15, the first split main body piece 77 and the second split main body piece 78 can be joined with a main body piece joining member 79 from the radial direction 23 of the stud bolt 8 to assemble the pressing portion main body 56.Therefore, even if the working space 87 secured between the packing retainer 7 and the gear wheel 9 is narrow, as shown in Figure 3, the pressing body 34 can be assembled and screwed onto the stud bolt 8.

[0071] Furthermore, by extending extension member 52 to an existing stud bolt 8 and screwing pressing portion body 56 onto extension member 52, even if the length of the existing stud bolt 8 is insufficient, pressing portion body 56 can be connected to stud bolt 8 via extension member 52. As a result, even if the length of the existing stud bolt 8 is insufficient, pressing body 34 can be screwed onto stud bolt 8 and tightened, and pressing portion body 56 can press retaining case 33 against the upper surface of packing gland 7, as shown in Figures 4, 13, and 14.

[0072] Also, as shown in Fig. 5, by wrapping a string-like O-ring 32 (see phantom line) around the outer circumferential surface of the valve rod 3 and bonding both ends to form an annular shape (see solid line), even if the working space 87 is narrow as shown in Fig. 3, the O-ring 32 can be placed on the outer circumferential surface of the valve rod 3 to close the gap between the outer circumferential surface of the valve rod 3 and the first through hole 15 of the packing gland 7 as shown in Fig. 4. Therefore, even if the working space 87 is narrow, the water leakage prevention device 31 can be attached to the shaft seal portion 20.

[0073] 9 and 10, since the retaining case 33 is sandwiched between the base portions 59 of the extension members 52, the retaining case 33 comes into contact with the base portions 59 of the extension members 52 in the rotation direction of the valve rod 3, restricting the rotation of the retaining case 33. This makes it possible to prevent the retaining case 33 from rotating together with the valve rod 3 (co-rotating) when the valve rod 3 rotates.

[0074] 8 and 9, both ends of the reamer bolt 69 and the nut 70 of the extension member 52 are disposed in the recessed portion 63 of the base portion 59 and are contained inside the radius R1 of the outer circumferential surface 62, so that both ends of the reamer bolt 69 and the nut 70 do not protrude radially outward from the outer circumferential surface 62. This makes it possible to prevent both ends of the reamer bolt 69 and the nut 70 from interfering with the retaining case 33, as shown in FIG.

[0075] 12 and 13, both ends of the reamer bolt 81 and the nut 82 of the pressing portion main body 56 are disposed in the recessed portion 75 and are contained inside the radius R2 of the outer circumferential surface 74, so that both ends of the reamer bolt 81 and the nut 82 do not protrude radially outward from the outer circumferential surface 74. This makes it possible to prevent both ends of the reamer bolt 81 and the nut 82 from interfering with the valve stem 3, as shown in FIG.

[0076] In the first embodiment described above, as shown in FIG. 3, two stud bolts 8 and two pressing bodies 34 are provided, but three or more stud bolts 8 may be provided and three or more pressing bodies 34 may be provided to match the number of stud bolts 8.

[0077] In the first embodiment, as shown in FIG. 11, the extension member 52 can be divided into two split extension pieces 65, 66, but it may also be divided into three or more split extension pieces.

[0078] In the first embodiment, as shown in FIG. 15, the pressing portion main body 56 can be divided into two divided main body pieces 77, 78, but it may also be divided into three or more divided main body pieces. (Second embodiment)

[0079] In the second embodiment, as shown in Figures 18 to 21, pressing body 101 is screwed onto stud bolt 8 via female thread 102 and is rotatable relative to stud bolt 8. Pressing body 101 has a fifth through hole 103 penetrating in axial direction 14 (up-down direction), a cylindrical portion 104, and a pressing portion main body 105 provided at the upper end of cylindrical portion 104. Female thread 102 is formed on the inner circumference of pressing body 101. The pressing portion main body 105 contacts the upper surface of the holding case 33 from above, and in this state, a gap is formed between the lower end of the cylindrical portion 104 and the upper surface of the packing gland 7 .

[0080] The pressing portion body 105 has an outer peripheral surface 106 having a predetermined radius R3. The radius R3 of the outer peripheral surface 106 of the pressing portion body 105 is larger than the radius R4 of the outer peripheral surface of the cylindrical portion 104. The outer peripheral surface 106 of the pressing portion body 105 has recessed portions 107 formed at multiple locations (four locations in Figs. 19 and 21) that are recessed radially inward of the outer peripheral surface 106.

[0081] As shown in FIG. 22, the pressing body 101 has first and second split pressing pieces 109, 110 that can be separated in the radial direction 23 of the stud bolt 8, and two (multiple) sets of pressing piece connecting members 111 that connect the first and second split pressing pieces 109, 110 to each other.

[0082] The pressing piece connecting member 111 has a reamer bolt 114 and nuts 115 that can be screwed onto both ends of the reamer bolt 114. Two (a plurality of) first bolt insertion holes 117 are formed in the first divided pressing piece 109, and two (a plurality of) second bolt insertion holes 118 are formed in the second divided pressing piece 110. The first and second bolt insertion holes 117, 118 open into the recessed portion 107 of the pressing portion main body 105.

[0083] The reamer bolt 114 is inserted into the first and second bolt insertion holes 117, 118, and nuts 115 are screwed onto both ends of the reamer bolt 114 and tightened, thereby joining the first divided pressing piece 109 and the second divided pressing piece 110 as shown in Fig. 21, and assembling the pressing body 101. At this time, both ends of the reamer bolt 114 and the nuts 115 are placed in the recessed portion 107 and are contained inside the radius R3 of the outer circumferential surface 106 of the pressing portion main body 105 as shown in Fig. 19. A method for preventing water leakage from the gate valve 1 using the water leakage prevention device 100 will be described below.

[0084] As shown in Figure 1, due to deterioration of the gland packing 4 over time, etc., water (liquid) in the valve box 2 may leak out from between the outer peripheral surface of the valve stem 3 and the inner peripheral surface of the packing gland 7 above the packing gland 7. If such a water leakage W occurs, a water leakage prevention device 100 (see Figure 18) is attached between the packing gland 7 and the large gear 9 as described below to prevent the water leakage W.

[0085] First, the existing nut 18 (see Fig. 1) is loosened, and the nut 18 is split using a nut splitter and removed from the stud bolt 8. Then, as shown in Figs. 5 and 6, an annular O-ring 32 is placed on the outer circumferential surface of the valve stem 3, and as shown in Fig. 7, the first divided retaining piece 41 and the second divided retaining piece 42 are joined with a retaining piece joining member 43 from the radial direction 22 of the valve stem 3 so that the valve stem 3 passes through the second through hole 37 of the retaining case 33, thereby assembling the retaining case 33. Thereafter, the O-ring 32 is fitted into the triangular groove 39 and held in the holding case 33.

[0086] Next, as shown in FIG. 22, the first split pressing piece 109 and the second split pressing piece 110 are screwed onto the stud bolt 8 from the radial direction 23 and joined with a pressing piece joining member 111 to assemble the pressing body 101.

[0087] At this time, the reamer bolt 114 of the pressure piece joining member 111 is inserted into the first bolt insertion hole 117 and the second bolt insertion hole 118, and nuts 115 are screwed onto both ends of the reamer bolt 114 and tightened, thereby joining the first split pressure piece 109 and the second split pressure piece 110 as shown in Figure 21.

[0088] As a result, the male thread of the stud bolt 8 and the female thread 102 of the pressing body 101 mesh with each other, and the pressing body 101 is extended onto the upper end of the stud bolt 8, as shown in Fig. 18. Thereafter, the pressing body 101 is turned and tightened onto the stud bolt 8, and as shown in Figs. 18 to 20, the pressing portion main body 105 of the pressing body 101 comes into contact with the upper surface of the retaining case 33 from above, pressing the retaining case 33 against the upper surface of the packing gland 7. As a result, the O-ring 32 is pressed against the outer circumferential surface of the valve stem 3 and the upper surface of the packing gland 7 and is compressed, and the O-ring 32 closes the gap between the outer circumferential surface of the valve stem 3 and the first through hole 15 of the packing gland 7, preventing water leakage W from the shaft seal portion 20.

[0089] In this case, as shown in FIG. 22, the first split pressing piece 109 and the second split pressing piece 110 can be joined with a pressing piece joining member 111 from the radial direction 23 of the stud bolt 8 to assemble the pressing body 101. Therefore, even if the working space 87 secured between the packing retainer 7 and the gear wheel 9 is narrow, as shown in FIG. 18, the pressing body 101 can be assembled and screwed onto the stud bolt 8.

[0090] 19, both ends of the reamer bolt 114 and the nut 115 are disposed in the recess 107 and are contained inside the radius R3 of the outer circumferential surface 106 of the pressing portion main body 105, so that both ends of the reamer bolt 114 and the nut 115 do not protrude radially outward from the outer circumferential surface 106. This makes it possible to prevent both ends of the reamer bolt 114 and the nut 115 from interfering with the valve stem 3.

[0091] In the above-described second embodiment, as shown in FIG. 18, two stud bolts 8 and two pressing bodies 101 are provided, but three or more stud bolts 8 may be provided and three or more pressing bodies 101 may be provided to match the number of stud bolts 8.

[0092] In the second embodiment, as shown in FIG. 22, the pressing body 101 can be divided into two divided pressing pieces 109 and 110, but it may be divided into three or more divided pressing pieces.

[0093] In the above first and second embodiments, as shown in FIG. 7, the holding case 33 can be separated into two divided holding pieces 41, 42, but it may also be separated into three or more divided holding pieces. [Explanation of symbols]

[0094] 1. Gate valve 2 Valve box 3 Valve stem 4 Gland packing (first seal member) 5 Packing box (storage section) 7 Packing retainer (retaining member) 8 Stud bolt (bolt) 9. Gear (rotational force transmission member) 14 Axial direction 15 First through hole 20 Shaft seal 22 Radial direction of valve stem 23 Radial direction of stud bolt 31 Water leakage prevention device 32 O-ring (second seal member) 33 Holding case (holding member) 34 Pressing body 37 Second Through Hole 41,42 Split holding piece 43 Retaining piece joint member 51 Female thread 52 Extension member 54 Male thread 55 Female thread 56 Pressing part body 62 Outer surface 65,66 Split joint piece 67 Joint piece for jointing 77,78 Split body piece 79 Body piece joint member 87 Working Space 89,90 Split pressing piece 91 Pressing piece joint member 100 Water leak prevention device 101 Pressing body 102 Female thread 109,110 Split pressing piece 111 Pressing piece joint member R1 given radius

Claims

1. a valve stem that penetrates a valve body, a first seal member that seals the penetration portion of the valve stem, a storage section in which the first seal member is stored, a pressing member that presses the first seal member stored in the storage section from the outside toward the inside of the valve body in the axial direction, and a plurality of bolts that fix the pressing member; The bolt is provided in the storage section, A first through hole is formed in the pressing member, A water leakage prevention device that prevents water leakage from a shaft seal of a valve in which a valve stem passes through a first through hole and a bolt passes through a pressing member, a second annular seal member disposed on an outer circumferential surface of the valve rod to close a gap between the outer circumferential surface of the valve rod and the first through hole of the pressing member; a holding member for holding the second seal member; a plurality of rotatable pressing bodies for pressing the holding member against the pressing member; A second through hole is formed in the holding member, The valve stem extends through the second through hole; The retaining member has a plurality of divided retaining pieces that can be separated in a radial direction of the valve stem from the second through hole, and a retaining piece joining member that joins the divided retaining pieces together, A water leakage prevention device characterized in that the pressing body is screwed onto the bolt via a screw and has a plurality of split pressing pieces that can be separated in the radial direction of the bolt, and a pressing piece joining member that joins the split pressing pieces together.

2. The pressing body has an extension member that is connected to the bolt via a screw, and a pressing part main body that is screwed into the extension member via a screw, The pressing portion main body presses the holding member against the pressing member, The extension member is rotatable relative to the bolt and has a plurality of split extension pieces that can be separated in the radial direction of the bolt, and an extension piece joining member that joins the split extension pieces together, The pressing portion main body is rotatable relative to the extension member and has a plurality of divided main body pieces that can be divided in the radial direction of the bolt, and a main body piece joining member that joins the divided main body pieces together, The split extension piece and the split main body piece constitute a split pressing piece, 2. The water leakage prevention device according to claim 1, wherein the extension piece connecting member and the main body piece connecting member form a pressing piece connecting member.

3. 3. The water leakage prevention device according to claim 2, wherein the retaining member abuts against the extension member in the rotational direction of the valve stem, thereby restricting the rotation of the retaining member.

4. The extension member has an outer circumferential surface having a predetermined radius, 3. The water leakage prevention device according to claim 2, wherein the extension piece joint member is contained inside the radius of the outer peripheral surface of the extension member.

5. A valve equipped with the water leakage prevention device according to any one of claims 1 to 4, A torque transmission member for transmitting a torque to the valve stem is provided on the valve stem outside the valve body, A valve characterized in that a water leakage prevention device is disposed between a pressing member and a rotational force transmission member.

6. A method for preventing water leakage from a valve using the water leakage prevention device according to claim 1, a second seal member disposed on an outer circumferential surface of the valve stem; Assembling the retaining member by joining the divided retaining pieces together with a retaining piece joining member so as to surround the valve rod from a radial direction of the valve rod and so that the valve rod passes through the second through hole of the retaining member; The second seal member is held by a holding member; The plurality of divided pressing pieces are screwed onto the bolts from the radial direction and joined together with a pressing piece joining member to assemble the pressing body; A method for preventing water leakage from a valve, comprising turning a pressing body and tightening it onto a bolt to press the retaining member against the pressing member, thereby pressing and compressing the second seal member against the outer peripheral surface of the valve stem and the pressing member.

7. The method for preventing water leakage from a valve as described in claim 6, characterized in that a string-like second sealing member is wrapped around the outer peripheral surface of the valve stem and both ends are bonded to form a circular ring shape and placed on the outer peripheral surface of the valve stem.

Images