The present invention relates to a gland packing and a packing structure.
Background technology
[0002]
　Japanese Unexamined Patent Publication No. 7-217745 (Patent Document 1) discloses a sealing device configured to seal the periphery of a movable shaft. This sealing device includes a plurality of gland packings (packing rings made of expanded graphite), each of which is arranged around a movable shaft, and two adapter packings that sandwich the plurality of gland packings (see Patent Document 1). ).
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Unexamined Patent Publication No. 7-217745
Outline of the invention
Problems to be solved by the invention
[0004]
　In the sealing device disclosed in Patent Document 1, for example, when the movable shaft slides, the expanded graphite (wear powder) caused by the gland packing is fixed to the movable shaft, and the expanded graphite is fixed to the movable shaft. Is scraped off by the adapter packing. As a result, for example, expanded graphite scraped by the adapter packing may remain on the sliding surface between the movable shaft and the gland packing. If expanded graphite remains on the sliding surface between the movable shaft and the gland packing, the expanded graphite may wear the inner peripheral surface of the gland packing and reduce the airtightness in the sealing device.
[0005]
　Further, in the sealing device disclosed in Patent Document 1, for example, when a lubricant is applied to the inner peripheral surface of the gland packing, the sliding surface between the movable shaft and the gland packing is caused by the sliding of the movable shaft. Lubricant may flow out early.
[0006]
　The present invention has been made to solve such a problem, and an object of the present invention is to suppress the residual expanded graphite on the sliding surface between the movable shaft and the gland packing, and to lubricate the sliding surface. It is an object of the present invention to provide a gland packing and a packing structure capable of suppressing a drug shortage.
Means to solve problems
[0007]
　A gland packing according to an aspect of the present invention is arranged around a movable shaft. This gland packing includes a gland packing body made of expanded graphite. The gland packing body has a cylindrical shape, and a plurality of layers are formed in the radial direction. The gland packing main body has first and second surfaces which are both end surfaces in the axial direction. The gland packing further includes an annular first sheet portion made of expanded graphite, an annular second sheet portion made of expanded graphite, an annular first porous member, and an annular second porous member. The first sheet portion is arranged on the first surface. The second sheet portion is arranged on the second surface. The first porous member is arranged on the first sheet portion. The second porous member is arranged on the second sheet portion.
[0008]
　This gland packing includes first and second porous members. Therefore, according to this gland packing, the expanded graphite generated on the sliding surface is adsorbed on the first and second porous members, so that the residual expanded graphite on the sliding surface can be suppressed. Further, according to this gland packing, when the lubricant is applied to the inner peripheral surface of the gland packing and the first and second porous members, the lubricant is held by the first and second porous members and slides. When the lubricant is insufficient on the moving surface, the lubricant can be supplied to the sliding surface from the first and second porous members, so that the running out of the lubricant on the sliding surface can be suppressed. In this gland packing, since a plurality of layers are formed in the radial direction in the gland packing main body, liquid can permeate in the axial direction of the movable shaft, but the first and second surfaces are on the first and second surfaces. Since the seat portions are arranged respectively, permeation leakage in the axial direction of the movable shaft is suppressed.
[0009]
　In the gland packing, the first and second sheet portions may be plane-symmetrical with a plane located between the first and second planes as a plane of symmetry.
[0010]
　In this gland packing, the plane located between the first and second planes is a plane of symmetry, and the first and second seat portions are plane-symmetrical. Therefore, according to this gland packing, the same sealing effect can be obtained regardless of which side the stuffing box is inserted into. As a result, the installer of the gland packing can arrange the gland packing in the stuffing box without being aware of the front and back sides of the gland packing.
[0011]
　In the gland packing, each of the first and second sheet portions includes the first and second sheets, and one of the first and second sheets covers the inner peripheral side of the first and second surfaces, while the first sheet. The outer peripheral side of the first and second surfaces is not covered, and the other of the first and second sheets covers the outer peripheral side of the first and second surfaces, while does not cover the inner peripheral side of the first and second surfaces. The 1st and 2nd sheets may partially overlap.
[0012]
　In this gland packing, one of the first and second sheets covers the inner peripheral side of the first and second surfaces, and the other of the first and second sheets covers the outer peripheral side of the first and second surfaces. The first and second sheets partially overlap. Therefore, according to this gland packing, since each of the first surface and the second surface of the gland packing main body is covered with the first and second sheets, it is possible to suppress permeation leakage in the axial direction of the movable shaft. .. Further, in this gland packing, one of the first and second sheets does not cover the outer peripheral side of both axial end faces of the gland packing main body, and the other of the first and second sheets is the axial end face of the gland packing main body. Does not cover the inner circumference side. That is, in this gland packing, steps are formed on the inner peripheral side and the outer peripheral side of the gland packing main body by the first and second sheets. According to this gland packing, one of the first and second sheets and the gland packing main body are caught at the step, and the other of the first and second sheets and the porous member are caught. Can be strengthened.
[0013]
　In the gland packing, each of the first and second porous members is a metal mesh molded product, and the inner diameter of one of the first and second sheets is the inner diameter of each of the first and second porous members. May be smaller than.
[0014]
　In this gland packing, the inner circumference of one of the first and second sheets is smaller than the inner diameter of each of the first and second porous members. Therefore, according to this gland packing, since the first and second sheets are located closer to the movable shaft, there is a possibility that the first and second porous members, which are metal mesh molded products, come into contact with the movable shaft. Can be reduced. As a result, it is possible to reduce the possibility that the first and second porous members, which are metal mesh molded products, wear the movable shaft. In this gland packing, since each of the first and second porous members is made of metal and has high hardness, the gland packing body is unlikely to protrude even when a tightening pressure is applied to the gland packing. As a result, according to this gland packing, a high tightening pressure can be maintained.
[0015]
　The gland packing may be impregnated with a lubricant.
[0016]
　A packing structure according to another aspect of the present invention is a structure in which a plurality of gland packings are arranged around a movable shaft. In this packing structure, each of the plurality of gland packings is the gland packing.
The invention's effect
[0017]
　According to the present invention, there is provided a gland packing and a packing structure capable of suppressing residual expanded graphite on the sliding surface between the movable shaft and the gland packing and suppressing running out of lubricant on the sliding surface. Can be done.
A brief description of the drawing
[0018]
[Fig. 1] Fig. 1 is an external perspective view of the gland packing.
[Fig. 2] Fig. 2 is a plan view of the gland packing.
FIG. 3 is a cross-sectional view taken along the line III-III of FIG.
[Fig. 4] Fig. 4 is a diagram showing an example of a packing structure using a gland packing.
FIG. 5 is a plan view of a mold used for manufacturing a gland packing.
6 is a sectional view taken along line VI-VI of FIG.
[Fig. 7] Fig. 7 is a flowchart showing a manufacturing procedure of gland packing.
FIG. 8 is a diagram showing a cross section of a gland packing in a modified example.
[Fig. 9] Fig. 9 is a diagram showing an arrangement of gland packings in a comparative example.
[Fig. 10] Fig. 10 is a diagram showing test results.
Mode for carrying out the invention
[0019]
　Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.
[0020]
　[1. Configuration of Gland Packing]
　FIG. 1 is an external perspective view of the gland packing 10 according to the present embodiment. The gland packing 10 is used, for example, to seal a through shaft (movable shaft) such as a valve.
[0021]
　As shown in FIG. 1, the gland packing 10 has a ring shape. A hole H1 is formed in the central portion of the gland packing 10. The gland packing 10 is arranged around the movable shaft by passing the movable shaft (not shown) through the hole H1. Generally, a plurality of gland packings 10 are arranged around the movable shaft. As a result, a seal of a movable shaft such as a valve is realized.
[0022]
　FIG. 2 is a plan view of the gland packing 10. FIG. 3 is a sectional view taken along line III-III of FIG. With reference to FIGS. 2 and 3, the gland packing 10 is configured by integrally molding a cylindrical gland packing main body 100, an annular sheet portion 110, 120, and an annular mesh molded product 130, 140. ing.
[0023]
　The gland packing body 100 is made of expanded graphite. In the gland packing main body 100, a plurality of layers are formed in the radial direction. Specifically, the gland packing main body 100 is formed by winding expanded graphite tape in a spiral or concentric shape. That is, by winding the expanded graphite tape, a plurality of layers are formed in the radial direction of the gland packing main body 100. In this expanded graphite tape, wrinkles extending in the longitudinal direction of the tape are formed at predetermined intervals in the width direction of the tape. By forming these wrinkles in advance, it is possible to control the position of the buckling point generated in the expanded graphite tape during integral molding.
[0024]
　The sheet portion 110 includes expanded graphite sheets 112 and 114, and the sheet portion 120 includes expanded graphite sheets 122 and 124. Each of the expanded graphite sheets 112, 114, 122, 124 is made of expanded graphite. Further, the expanded graphite sheet 112 and the expanded graphite sheet 122 have the same shape, and the expanded graphite sheet 114 and the expanded graphite sheet 124 have the same shape. The inner diameter of each of the expanded graphite sheets 112 and 122 is larger than the inner diameter of each of the expanded graphite sheets 114 and 124, and the outer diameter of each of the expanded graphite sheets 112 and 122 is larger than the outer diameter of each of the expanded graphite sheets 114 and 124. big.
[0025]
　The expanded graphite sheet 114 is arranged on one surface (upper surface) of the gland packing main body 100, and the expanded graphite sheet 124 is arranged on the other surface (lower surface) of the gland packing main body 100. The expanded graphite sheet 112 is arranged on the expanded graphite sheet 114, and the expanded graphite sheet 122 is arranged on the expanded graphite sheet 124. That is, in the gland packing main body 100, the seat portions 110 and 120 are in the axial direction of the gland packing main body 100 among the planes perpendicular to the axial direction of the movable shaft when the gland packing 10 is arranged around the movable shaft. The planes located between the upper surface and the lower surface, which are both end faces of the above, are planes of symmetry. Therefore, according to the gland packing 10, the same sealing effect can be obtained regardless of which side the stuffing box is inserted into. As a result, the installer of the gland packing 10 can arrange the gland packing 10 in the stuffing box without being aware of the front and back sides of the gland packing 10.
[0026]
　In the gland packing 10, the expanded graphite sheets 114 and 124 cover the inner peripheral sides (inner peripheral sides of the upper surface and the lower surface) of both axial end surfaces of the gland packing main body 100, and the expanded graphite sheets 112 and 122 cover the gland packing main body 100. It covers the outer peripheral side of both end faces in the axial direction (the outer peripheral side of the upper surface and the lower surface). Further, the expanded graphite sheet 112 and the expanded graphite sheet 114 partially overlap each other, and the expanded graphite sheet 122 and the expanded graphite sheet 124 partially overlap each other. In the gland packing 10, since a plurality of layers are formed in the gland packing main body 100 in the radial direction, the liquid can permeate in the axial direction of the movable shaft. However, according to the gland packing 10, since the upper surface and the lower surface of the gland packing main body 100 are covered by the sheet portions 110 and 120, respectively, it is possible to suppress permeation leakage in the axial direction of the movable shaft (not shown). Further, according to the gland packing 10, as described above, the expanded graphite sheets 114 and 124 cover the inner peripheral sides of both end faces in the axial direction of the gland packing main body 100, and the expanded graphite sheets 112 and 122 are the shafts of the gland packing main body 100. Since it covers the outer peripheral sides of both end faces in the direction, it is possible to prevent the gland packing main body 100 (made of expanded graphite) from biting into the mesh molded products 130 and 140 during pressure molding in the manufacturing process of the gland packing 10.
[0027]
　Further, in the gland packing 10, the expanded graphite sheets 114 and 124 do not cover the outer peripheral sides of both axial end surfaces of the gland packing main body 100, and the expanded graphite sheets 112 and 122 are the inner circumferences of both axial end surfaces of the gland packing main body 100. Do not cover the side. That is, in the gland packing 10, steps D1 and D3 are formed on the outer peripheral side of the gland packing main body 100, and steps D2 and D4 are formed on the inner peripheral side of the gland packing main body 100. The steps D2 and D4 are formed between the expanded graphite sheets 114 and 124 and the expanded graphite sheets 112 and 122, which are curved during pressure molding, respectively. By catching the gland packing main body 100 on the steps D1 and D3, the seat portions 110 and 120 and the gland packing main body 100 are firmly joined. Further, the sheet portions 110 and 120 and the mesh molded products 130 and 140 are firmly joined to each other by catching the mesh molded products 130 and 140 at the steps D2 and D4, respectively.
[0028]
　Each of the mesh molded products 130 and 140 is annular and is made of metal. Each of the mesh molded products 130 and 140 is produced, for example, by spirally knitting a metal wire, putting it into a molding die, and pressure-molding it. Each of the completed mesh molded products 130 and 140 is a porous and high-hardness member.
[0029]
　[2. Packing structure using gland packing]
　FIG. 4 is a diagram showing an example of a packing structure using gland packing 10. As shown in FIG. 4, in the packing structure 20, five gland packings 10 are arranged in a stuffing box 45 formed around the movable shaft 30. In the stuffing box 45, the gland packing 10 is axially pressed by the gland retainer 40. As a result, the seal of the movable shaft 30 is realized. In the gland packing 10, since each of the mesh molded products 130 and 140 is made of metal and has high hardness, the gland packing main body 100 is unlikely to protrude even when a tightening pressure is applied to the gland packing 10. As a result, according to the gland packing 10, a high tightening pressure can be maintained.
[0030]
　For example, when the movable shaft 30 slides in the axial direction, expanded graphite (wear powder) caused by the gland packing main body 100 may stick to the movable shaft 30. If expanded graphite remains on the sliding surface between the gland packing 10 and the movable shaft 30, the expanded graphite wears the inner peripheral surface of the gland packing 10 and the airtightness of the packing structure 20 is lowered. However, in the packing structure 20, the mesh molded products 130 and 140 are porous, and the mesh molded products 130 and 140 can adsorb the expanded graphite generated on the sliding surface. That is, according to the packing structure 20, the expanded graphite generated on the sliding surface is discharged to the outside of the sliding surface by the mesh molded products 130 and 140, so that the residual expanded graphite on the sliding surface is suppressed. Can be done. In particular, when a lubricant (for example, a hydrocarbon-based lubricant) is applied to the sliding surface, the expanded graphite is mesh-molded along with the flow of the lubricant infiltrating the mesh-molded products 130 and 140. It moves to the inner side (outer peripheral side) in the radial direction of the products 130 and 140. As a result, more expanded graphite can be retained in the mesh molded products 130 and 140.
[0031]
　Further, in the gland packing 10, when the lubricant is applied to the inner peripheral surface of the gland packing 10 and the mesh molded products 130 and 140, the lubricant is held by the mesh molded products 130 and 140. Therefore, according to the gland packing 10, when the lubricant is insufficient on the sliding surface, the lubricant can be supplied to the sliding surface from the mesh molded products 130 and 140, so that the lubricant running out on the sliding surface is suppressed. be able to.
[0032]
　In order for the mesh molded products 130 and 140 to maintain the strength and appropriately retain the lubricant and expanded graphite, the porosity of the mesh molded products 130 and 140 is preferably 50 to 70%.
[0033]
　[3. Method for Manufacturing Gland Packing]
　FIG. 5 is a plan view of a mold 50 used for manufacturing the gland packing 10. FIG. 6 is a sectional view taken along line VI-VI of FIG. Note that FIG. 6 shows a state in which each material is arranged in the mold 50 and before pressure molding. As shown in FIGS. 5 and 6, the mold 50 includes a material holding portion 52 and a pressurizing portion 54. A plurality of types of materials are arranged at predetermined positions of the material holding portion 52, and the plurality of types of materials are pressed by the pressurizing portion 54. As a result, a plurality of types of materials are integrally molded.
[0034]
　FIG. 7 is a flowchart showing a manufacturing procedure of the gland packing 10. The process shown in this flowchart is executed, for example, by the manufacturing apparatus of the gland packing 10.
[0035]
　With reference to FIGS. 5, 6 and 7, the manufacturing apparatus arranges the mesh molded product 140 on the material holding portion 52 (step S100). The manufacturing apparatus arranges the expanded graphite sheet 122 on the mesh molded product 140 (step S110). The manufacturing apparatus arranges the expanded graphite sheet 124 on the expanded graphite sheet 122 (step S120). The manufacturing apparatus arranges the gland packing main body 100 on the expanded graphite sheet 124 (step S130). The manufacturing apparatus arranges the expanded graphite sheet 114 on the gland packing main body 100 (step S140). The manufacturing apparatus arranges the expanded graphite sheet 112 on the expanded graphite sheet 114 (step S150). The manufacturing apparatus arranges the mesh molded product 130 on the expanded graphite sheet 112 (step S160). After that, the manufacturing apparatus presses the pressure unit 54 to perform pressure molding of the material (step S170). As a result, the gland packing 10 is manufactured.
[0036]
　[4. Features] As described
　above, the gland packing 10 includes mesh molded products 130 and 140. Therefore, according to the gland packing 10, since the expanded graphite generated on the sliding surface is adsorbed on the mesh molded products 130 and 140, the residual expanded graphite on the sliding surface can be suppressed. Further, according to the gland packing 10, when the lubricant is applied to the inner peripheral surface of the gland packing 10 and the mesh molded products 130 and 140, the lubricant is held by the mesh molded products 130 and 140 on the sliding surface. When the lubricant is insufficient, the lubricant can be supplied from the mesh molded products 130 and 140 to the sliding surface, so that it is possible to prevent the lubricant from running out on the sliding surface. In the gland packing 10, since a plurality of layers are formed in the radial direction in the gland packing main body 100, liquid can permeate in the axial direction of the movable shaft, but the sheet portion 110 is placed on both sides of the gland packing main body 100. , 120 are arranged respectively, so that permeation leakage in the axial direction of the movable shaft is suppressed.
[0037]
　[5. Modifications] Although
　the embodiments have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the embodiments. Hereinafter, a modified example will be described. However, the following modifications can be combined as appropriate.
[0038]
　<5-1> In the
　above embodiment, it is assumed that the inner diameters of the gland packing main body 100 and the expanded graphite sheets 114 and 124 and the inner diameters of the mesh molded products 130 and 140 are substantially the same. However, the relationship between the inner diameters of each member is not limited to this.
[0039]
　FIG. 8 is a diagram showing a cross section of the gland packing 10A in the modified example. As shown in FIG. 8, for example, the inner diameters of the gland packing main body 100A and the expanded graphite sheets 114A and 124A may be smaller than the inner diameters of the mesh molded products 130 and 140. That is, the inner circumferences of the expanded graphite sheets 114A and 124A may be shorter than the inner circumferences of the mesh molded products 130 and 140. According to the gland packing 10A, since the gland packing main body 100A and the expanded graphite sheets 114A and 124A are located closer to the movable shaft, the possibility that the metal mesh molded products 130 and 140 come into contact with the movable shaft is reduced. Can be done. As a result, the possibility that the metal mesh molded products 130 and 140 wear the movable shaft can be reduced.
[0040]
　<5-2> In the
　above embodiment, the expanded graphite sheets 114 and 124 having a small inner diameter and outer diameter are arranged at positions close to the gland packing main body 100, and the inner and outer expanded graphite sheets 112 and 122 having a large inner diameter and outer diameter are arranged. It was arranged at a position far from the gland packing main body 100. However, the position of each expanded graphite sheet is not limited to this. For example, the expanded graphite sheets 114 and 124 having a small inner diameter and outer diameter are arranged at positions far from the gland packing main body 100, and the inner and outer expanded graphite sheets 112 and 122 having a large inner diameter and outer diameter are arranged at positions close to the gland packing main body 100. You may.
[0041]
　<5-3> In the
　above embodiment, each of the mesh molded products 130 and 140 is made of metal. However, each of the mesh molded products 130 and 140 does not necessarily have to be made of metal. Each of the mesh molded products 130 and 140 may be composed of, for example, carbon fiber, carbon fiber, alumina, a ceramic filter or the like. That is, each of the mesh molded products 130 and 140 may be made of a member that is more porous and harder than the gland packing main body 100.
[0042]
　[6. Examples, etc.]
　Examples will be described below.
[0043]
　<6-1. Example>
　(Mesh molded product)
　Using a metal wire having a wire diameter (diameter) of 0.15 mm, knitting was performed so that the width was 16 mm. 1.4 g of knitted metal wire was prepared. The prepared metal wire was put into a molding die having an inner diameter of 24 mm and an outer diameter of 37 mm in a spiral shape. Then, pressure molding was performed at a molding surface pressure of 40 N / mm 2 . As a result, a molded product having a thickness of 0.75 mm was completed. Two mesh molded products were prepared in the same manner.
[0044]
　(Expanded Graphite Sheet)
　Two expanded graphite sheets were prepared by punching a 0.75 mm thick expanded graphite sheet with a punching die having an inner diameter of 24 mm and an outer diameter of 35 mm. Further, two expanded graphite sheets were prepared by punching an expanded graphite sheet having a thickness of 0.75 mm with a punching die having an inner diameter of 26 mm and an outer diameter of 37 mm.
[0045]
　(Grand packing body)
　4.29 g of expanded graphite sheet (tape) having a thickness of 0.38 mm and a width of 14 mm, which was habituated to a depth of 0.3 mm so as to extend in the sheet longitudinal direction at intervals of 2 mm in the sheet width direction, was prepared. .. The gland packing main body was prepared by winding the expanded graphite sheet.
[0046]
　(Grand packing) In the
　procedure shown in FIG. 7, each material was put into a mold and then pressure-molded at a molding surface pressure of 40 N / mm 2 . Then, the pressure-molded molded product was impregnated with a hydrocarbon-based lubricant. Then, it was dried in an environment of 80 ° C. for 4 hours.
[0047]
　<6-2. Comparative Example>
　A gland packing according to the gland packing disclosed in Japanese Patent Application Laid-Open No. 7-217745 was prepared.
[0048]
　<6-3. Tests and Results> The
　gland packing according to the examples was arranged as shown in FIG. 4, and the gland packing according to the comparative example was arranged as shown in FIG. In Examples and Comparative Examples, the movable shaft sealed by the gland packing was slid in the axial direction, and the amount of fluid leakage was measured. The test fluid pressure was 25.9 MPa, the test temperature was room temperature, and the test fluid was helium gas. The test method was based on ISO15848-1 (2015).
[0049]
　FIG. 10 is a diagram showing test results. With reference to FIG. 10, the horizontal axis represents the number of slides and the vertical axis represents the amount of fluid leakage. It was confirmed that the leak amount (L1) of the example was improved as compared with the leak amount (L2) of the comparative example.
Code description
[0050]
　10 gland packing, 20 packing structure, 30 movable shaft, 40 gland restraint, 45 stuffing box, 50 mold, 52 material holding part, 54 pressurizing part, 100 gland packing body, 110, 120 sheet part, 112, 114, 122 , 124 Expanded graphite sheet, 130, 140 mesh molded product.
The scope of the claims
[Claim 1]
　It is a gland packing arranged around a movable shaft,
　and includes a gland packing main body made of expanded graphite which is tubular and has a plurality of layers formed in the radial direction, and the gland packing main
　body is axial. The
　gland packing has first and second surfaces which are both end surfaces, and the gland packing has
　an annular first sheet portion made of expanded graphite arranged on the first surface and an expansion arranged on
　the second surface. An annular second sheet portion made of graphite, an annular
　first porous member arranged on the first sheet portion, and
　an annular second porous member arranged on the second sheet portion are further added. Prepare, ground packing.
[Claim 2]
　The gland packing according to claim 1, wherein the first and second sheet portions are plane-symmetric with a surface located between the first and second surfaces as a plane of symmetry.
[Claim 3]
　Each of the first and second sheet portions includes
　the first and second sheets, and one of the first and second sheets covers the inner peripheral side of the first and second surfaces, while the first sheet. And the outer peripheral side of the second surface,
　and the other of the first and second sheets covers the outer peripheral side of the first and second surfaces, while not covering the inner peripheral side of the first and second surfaces.
　The gland packing according to claim 1 or 2 , wherein the first and second sheets partially overlap each other.
[Claim 4]
　Each of the first and second porous members is a metal mesh molded product, and
　the inner diameter of one of the first and second sheets is larger than the inner diameter of each of the first and second porous members. The small gland packing according to claim 3.
[Claim 5]
　The gland packing according to any one of claims 1 to 4, which is impregnated with a lubricant.
[Claim 6]
　A packing structure in which a plurality of gland packings are arranged around a movable shaft,
　and each of the plurality of gland packings is the gland packing according to any one of claims 1 to 5. .