JP3162992U - Fitting gasket - Google Patents

Abstract

[PROBLEMS] To ensure that air and water leaks of pipe joints can be found reliably at the stage of air pressure or water pressure test after the completion of piping work, and confirm that there is no construction failure at the test stage before moving to safe full-scale operation. Provided is a gasket for pipe fittings. An annular elastic gasket that is installed inside a pipe joint and prevents liquid leakage from a pipe by compression contact is installed. A plurality of protrusions 30 are formed in the circumferential direction of the gasket on the contact surface with the end surface of the collar portion 7 or the outer peripheral surface of the pipe. When the height of each projection 30 exceeds the lip side end portion 32 of the gasket, and the pipe joint is simply attached, the gasket and the flange portion or the flange end surface or the pipe outer peripheral surface are interposed by the projection. When there is a gap channel between them, and when the pipe joint is tightened, the gasket is compressed and the gap channel disappears to establish a seal. [Selection] Figure 3

Description

  The present invention relates to a gasket for a pipe joint that can be reliably detected at the stage of air pressure or water pressure test after completion of piping work, and can be shifted to safe full-scale operation after confirming that there is no construction failure at the test stage. .

  In plumbing for water supply and air conditioning, in order to connect the pipes in a straight line, the flange type coupling method is often used in terms of mechanical strength of the connecting part and piping workability of the large diameter pipe. It is preferable to use a loose flange type pipe joint that allows easy matching of the bolt through holes of the flange. In the loose flange type pipe joint, a sheet packing is disposed between the flange portions at both ends of the pipe, and the sheet packing is fastened with a bolt and a nut to obtain a high sealing force.

  In the loose flange type pipe joint, there is a type in which an O-ring is used together with a seat packing in order to obtain a high sealing force. For example, in Japanese Patent Laid-Open No. 9-14545, an O-ring is disposed on the inner peripheral surface side of the packing, and the outer diameter of the packing is substantially equal to the outer diameter of the loose flange. On the other hand, in Japanese Utility Model Laid-Open No. 4-133430, an O-ring is disposed on the inner peripheral surface side of the outer ring corresponding to the seat packing, and the outer diameter of the outer ring is larger than the outer diameter of the pipe collar portion. When seat packing and an O-ring are used in combination, as in JP-A-9-14545 and JP-A-4-133430, the sealing force between both pipes can be relatively high, but the sealing force is such that overtightening of the bolt is not necessary. Is not high and requires a strong tightening force, which is almost the same as in the prior art. In addition, since this O-ring is usually an elastic material having a circular cross section, when the inside of the pipe becomes negative pressure, it is easily deformed inward, resulting in a problem that the sealing force between the two pipes is reduced.

  The present inventor has already proposed Utility Model Registration No. 3136954 in order to improve the problem that the sealing force between pipes does not increase in the conventional loose flange type pipe joint. As shown in FIG. 1, the loose flange type pipe joint 1 has a gasket 2 and a reinforcing ring 3 disposed between the flange portions 7 of the pipe 5 instead of the seat packing, and the pipe joint 1 is assembled by the loose flanges 8 and 8. .

  The gasket 2 to be used has a substantially inverted V-shaped lip shape as shown by the alternate long and short dash line in FIG. The outer diameter of the gasket 2 is substantially equal to the inner diameter of the reinforcing ring 3, and the reinforcing ring 3 has a rectangular cross section. The gasket 2 has an inverted V-shaped cross section, and the lower center portion of the cross section is recessed. In the cross section of the gasket 2, the lip portions 10, 10 extend obliquely downward and outward, the distance between the tips of both lip portions is larger than the thickness of the reinforcing ring 3, and the side surface of the gasket is pipe 5 when compressed. It closely adheres to the front end surface of the collar portion 7.

Japanese Patent Laid-Open No. 9-14545 Japanese Utility Model Publication No. 4-133430 Utility Model Registration No. 3136954

  Since the loose flange-type pipe joint 1 is sealed using the gasket 2 that is relatively easy to compress and deform, the tightening force by each bolt only needs to withstand the tube pulling force, and is tightened as in a conventional seat packing. There is no need. In the pipe joint 1, as the pipe internal pressure increases, the lip portion 10 of the compression-deformed gasket 2 is pressed against the end face of the collar portion and the outer peripheral surface thereof toward the reinforcing ring 3, and the problem of water leakage is obtained by obtaining high sealing force. Does not occur. On the other hand, the pipe joint 1 is frequently lightly sealed when the lip parts 10 and 10 are pushed to the end face side of the collar part with a slight pressure inside the pipe, even by hand tightening with bolts and nuts. There may be no air leak or water leak in the test or water pressure test.

  This type of pipe joint is subjected to air pressure test and water pressure test of all pipes after the completion of the pipe work, and after confirming that there is no construction failure by this test, it shifts to safe full-scale operation. At this time, in the installation work of the pipe joint, even if there is a construction failure such as leaving the bolt and nut lightly hand-tightened or temporarily fixed without tightening with a spanner tool or forgetting to tighten some bolts, If there is no air leak or water leak in the pressure test or water pressure test, the leak cannot be found at the test stage. If full operation is started with no leaks found, water leakage will occur from the pipe joint after completion of construction. The air pressure test and the water pressure test become completely meaningless.

  The present invention has been proposed in order to improve the above-mentioned problems associated with conventional pipe joints, and an elastic gasket that can reliably detect forgotten tightening of pipe joints and poor installation at the stage of pneumatic tests and hydraulic pressure tests. It is intended to provide. Another object of the present invention is to provide a gasket for a loose flange type pipe joint that can detect a deficiency in piping connection in a test stage and can achieve complete piping during full-scale operation. Another object of the present invention is to provide a gasket for a housing-type pipe joint that can detect a deficiency in piping connection in a test stage and can achieve complete piping during full-scale operation.

  The gasket according to the present invention is an annular elastic gasket that is installed inside a pipe joint and prevents liquid leakage from the pipe by compression and adhesion. In the gasket according to the present invention, one or a plurality of protrusions are formed in the circumferential direction of the gasket at the contact surface with the flange portion or the flange end surface or the pipe outer peripheral surface, and the height of each protrusion is the peripheral end portion of the gasket. If the pipe joint is simply attached by crossing the gap, a gap flow path exists between the gasket and the flange or flange end face or pipe outer peripheral surface due to the protrusion, while the pipe joint is tightened. In this state, the gasket is compressed, the gap flow path disappears, and sealing is established. In this elastic gasket, instead of arranging the plurality of protrusions in the circumferential direction, an annular protrusion provided with one or a plurality of transverse grooves may be formed.

  In the gasket of the present invention, a sealing member is interposed between the flange end faces of both pipes, and then both flanges or fitting loose flanges are joined and tightened. At this time, an annular elastic gasket and the gasket are used as the sealing members. It can apply to the pipe joint which uses the metal reinforcement ring arrange | positioned at the outer peripheral side. This gasket forms one or more protrusions in the circumferential direction of the gasket on the contact surface with the flange or flange end surface, and each protrusion is higher than the side end of the gasket in the axial direction. When an elastic gasket and a reinforcing ring are disposed between both flange portions and a pipe joint is simply attached with a bolt and a nut, a gap flow path is formed between the gasket and the flange portion or the flange end surface by the interposition of the protrusion. On the other hand, when the pipe joint is tightened, the gasket is compressed, the gap flow path disappears, and the seal is established. Preferably, a plurality of protrusions are formed at equal intervals in the circumferential direction on both side surfaces of the gasket.

  The gasket of the present invention may be applied to a pipe joint in which an annular elastic gasket is fitted to the ends of both pipes, a housing is covered on the gasket, and the housing is tightened with bolts and nuts. This gasket forms one or more protrusions on the inner peripheral surface of the gasket at the contact surface with the outer peripheral surface of the pipe, and each protrusion is inward of the peripheral edge of the gasket in the diametrical direction. When the pipe joint is simply attached with bolts and nuts, there is a gap flow path between the gasket inner peripheral surface and the pipe outer peripheral surface due to the interposition of the projection, while the pipe joint is tightened. Then, the gasket is compressed, the gap flow path disappears, and the sealing is established. Preferably, a plurality of inward projections are formed at equal intervals in the circumferential direction on the inner peripheral surfaces of both sides of the gasket.

  The gasket according to the present invention is made of a material that is relatively easy to compress and deform. When installed inside a pipe joint, the entire joint is sealed by the gasket, and the tightening force by each bolt and nut is enough to withstand the pipe pulling force. When tightening the bolt and nut for temporary fixing, the lip of the gasket is pushed toward the end face of the pipe collar and the outer peripheral face of the pipe, but the protrusion formed on the end face of the collar and the outer peripheral face of the pipe Thus, a gap between the gasket side face or the inner peripheral face is maintained, and the gap flow path is always formed without the gasket being in close contact with the flange end face or the pipe outer peripheral face. Due to the formation of this gap flow path, if only the bolts are temporarily fixed or hand-tightened, an air leak or a water leak will always occur from the pipe joint in a water pressure test or the like.

  The pipe joint provided with the gasket of the present invention has the gap flow path described above when the bolt is sufficiently tightened with a tightening tool such as a spanner, and the protrusion of the gasket is pressed and compressed to closely contact with the end face of the collar portion or the outer peripheral surface of the pipe. Disappears and complete airtightness of the connecting part is achieved, completely preventing air and water leakage. If the pipe fitting with the gasket of the present invention is installed after the completion of piping work after tightening the bolts, if you perform an air pressure test or water pressure test on all the pipes, you should forget to tighten the bolts, forget to insert any number of bolts, When there is a construction failure such as completeness, air leaks and water leaks will always occur, and it is possible to reliably detect defective piping connections.

  Since the pipe joint provided with the gasket of the present invention is relatively easily compressed and deformed, each bolt is tightened with a tightening tool to withstand the tube pulling force and does not need to be tightened as strongly as the conventional seat packing. If this pipe joint is a loose flange type pipe joint, the higher the pipe internal pressure, the higher the pressure on the seal side surface and the outer peripheral face of the compression deformed gasket, and the higher the sealing force. Due to this high sealing force, this loose flange type pipe joint does not require a strong tightening force by a tightening tool, and the gasket does not break during tightening and use, so there is no problem of water leakage.

It is a whole sectional view of a loose flange type pipe joint. It is an expanded sectional view of the principal part of FIG. 1 which shows the conventional gasket. In a loose flange type pipe joint, it is principal part sectional drawing which shows the elastic gasket and reinforcement ring before the fastening which concern on this invention. It is a side view of the elastic gasket and reinforcement ring in the pipe joint of FIG. It is principal part sectional drawing which shows the gasket after clamp | tightening with respect to FIG. In a housing type pipe joint, it is principal part sectional drawing which shows the gasket before the fastening which concerns on this invention. It is principal part sectional drawing which shows the gasket after clamp | tightening with respect to FIG. It is a whole sectional view showing the state before bolt and nut tightening about another housing type pipe joint.

  In the present invention, an annular elastic gasket is installed inside the pipe joint, and a plurality of protrusions are formed in the circumferential direction of the elastic gasket on the contact surface with the flange end face or the pipe outer peripheral face. It needs to be higher than the peripheral edge of the gasket. The pipe joints to which the present invention can be applied include flange-type pipe joints, loose-flange-type pipe joints 1 (see FIG. 1), Victorian-type or housing-type pipe joints (see FIG. 8), dresser-type pipe joints, sliding An example is an expandable pipe joint.

  In the elastic gasket of the present invention, the protrusions may be arranged sideways or inward with respect to the gasket at the mounting position. One or a plurality of the protrusions are provided on the side surface and the inner peripheral surface of the elastic gasket, and in the case of a plurality of protrusions, it is preferable to arrange them at equal intervals in the circumferential direction. Generally, the number of the protrusions may be about 2 to 36 if they are arranged at equal intervals in the circumferential direction. As shown in FIG. 4, this protrusion may be generally circular. In addition, this protrusion is usually in the shape of a hemisphere, and in FIG.

  According to the present invention, since it is sufficient that a gap flow path exists between the gasket and the flange portion or the flange end surface or the pipe outer peripheral surface, in the elastic gasket, instead of arranging the plurality of protrusions in the circumferential direction, one or more An annular ridge provided with a plurality of transverse grooves may be formed. When this elastic gasket is installed inside the pipe joint, air leakage and water leakage occur through the transverse groove of the ridge in the gasket if only bolts and nuts are temporarily fixed or hand-tightened.

  The present invention will be supplementarily described with reference to the drawings. In the loose flange type pipe joint 1 shown in FIG. 1, the connection pipes 5 and 5 are the same or similar metal pipes or plastic pipes, and pipes or metal pipes having different inner diameters. A plastic tube may be used. Although various metals can be used for the pipe 5 and the flange 8, the pipe 5 is preferably made of stainless steel, and the flange 8 is made of stainless steel, carbon steel or casting. In the case of carbon steel or casting, galvanization or plastic coating may be applied.

  The elastic gasket 14 is made of elastic rubber or plastic. For example, polypropylene, polyester, polyamide, polyethylene, polyacetal or the like is used, and when used for piping in a chemical plant or the like, its peripheral surface has corrosion resistance. It is preferable to coat a thin film. The elastic gasket 14 has an outer diameter substantially equal to the inner diameter of the reinforcing ring 12. The elastic gasket 14 is usually installed separately from the reinforcing ring 12, but may be integrated by inserting the reinforcing ring 12 on the outer peripheral surface thereof. The elastic gasket 14 is compressed and deformed to reduce its thickness, and matches the thickness of the reinforcing ring 12.

  The reinforcing ring 12 is made of an annular thin stainless steel, carbon steel or casting. The reinforcing ring 12 is formed with at least one positioning extension 34 (FIG. 4) protruding outward in the radial direction, and a bolt through hole 18 is provided in the extension. In the reinforcing ring 12, the number of the extension portions 34 can be arbitrarily determined according to the number and position of the bolt through holes 16 (FIG. 3) of the flange 8, for example, as shown in FIG. You may arrange in three at intervals of 120 °.

  As shown in FIG. 1, the loose flange type pipe joint 1 is fitted with pipes 5 and 5 with known loose flanges 8, respectively, and ends the pipes or welds a stub end. For example, in a pipe processing factory or a piping site, the rib portion is formed by forming a rib portion 7 at right angles to the outside in the diameter direction by a known tapping machine, and then the other end portion of the pipe is similarly tapped. Process. Thereafter, the reinforcing ring 12 and the elastic gasket 14 are interposed between the end faces of the flange portion 7 of the pipe 5, and then both the flanges 8 and 8 are coupled and tightened with the bolt 20 and the nut 22. It is also possible to fit and fix the half-shaped flange after the tapping process.

  The elastic gasket 14 and the reinforcing ring 12 can be attached not only to the loose flange type pipe joint 1 as shown, but also to a normal flange type pipe joint. In this case, the elastic gasket is not the end face of the collar part. In direct contact with the flange end face. This flange-type pipe joint may have a structure in which the flange is welded to the front end surface of the pipe as disclosed in Utility Model Registration No. 3152172.

  Next, the present invention will be described based on an embodiment. The same members as in the prior art will be described with reference to FIG. 1, and the members related to the present invention will be illustrated in FIGS. In the loose flange-type pipe joint 1 of FIG. 1, the metal loose flanges 8 and 8 are formed separately from the pipe 5, and the planar shape thereof is substantially a donut shape. In the flange 8, for example, six bolt through holes 16 are provided at equal intervals in the circumferential direction, and the flange inner diameter is substantially equal to the outer diameter of the pipe 5.

  The flange 8 can be fitted to the pipe 5 before the pipe end is blown or a stub end (not shown) is welded to the pipe end. Good. As shown in FIGS. 3 and 4, both the pipes 5 and 5 abut the front end face of the flange portion 7 through the reinforcing ring 12 and the elastic gasket 14, and the through hole 16 of the flange 8 and the through hole of the reinforcing ring 12. A bolt 20 (FIG. 1) is passed through 18 (FIG. 4) and temporarily fixed with a nut 22. The reinforcing ring 12 can be accurately positioned when the bolts 20 are passed through the two through holes 18, and all the bolts 20 are tightened with nuts 22 after the positioning.

  The elastic gasket 14 has an annular plane as shown in FIG. The elastic gasket 14 is determined so that its outer diameter is substantially equal to the inner diameter of the reinforcing ring 12 and its inner diameter is equal to or slightly larger than the inner diameter of the connection pipe 5. As shown in FIG. 3, the elastic gasket 14 has a substantially inverted V-shaped lip cross section, and the lip portions 24, 24 extend obliquely downward and outward. The distance between the tips of the lip portions 24, 24 is larger than the thickness outside the gasket, that is, the axial width. Since the elastic gasket 14 has a substantially inverted V-shaped cross section, the lower central portion of the cross section is slightly recessed. The lip valley 28 causes the side surfaces 26 and 26 of the elastic gasket 14 to be brim due to the internal pressure of the pipe. 7 and the outer peripheral surface 29 are crimped toward the reinforcing ring 12 (see FIG. 5).

  The elastic gasket 14 is formed with lateral projections 30 in the circumferential direction on both side surfaces thereof. In FIG. 4, the number of projections 30 is 12 at regular intervals in the circumferential direction. Each lateral protrusion 30 needs to be higher than the lip side end portion 32 of the gasket 14 in the axial direction (see FIG. 3). Further, it is desirable that the lateral protrusion 30 is located outward from the lip valley portion 28 in the diameter direction.

  The reinforcing ring 12 is made of a relatively hard metal. The reinforcing ring 12 is provided with extending portions 34 and 34 projecting outward in the opposite direction with respect to the diametrical direction, and the bolt through holes 18 are respectively provided in the extending portions. As shown in FIG. 3, the reinforcing ring 12 has a rectangular cross section, and its thickness, that is, the axial width is thinner than the axial width of the elastic gasket 14 by the compression of the gasket. The reinforcing ring 12 has an outer diameter substantially equal to the outer diameter of the pipe collar portion 7 and an inner diameter larger than the inner diameter of the pipe 5. It is desirable that the reinforcing ring 12 has a strength approximately equal to or higher than the strength of the connection pipe 5 with respect to the pipe internal pressure.

  In the loose flange type pipe joint 1, when the bolt 20 and the nut 22 are hand-tightened to temporarily fix the bolt, the lip portion 24 of the elastic gasket 14 is pushed toward the front end face of the pipe collar portion 7 by the pipe internal pressure. However, the end face of the collar portion keeps a gap with the gasket side face 26 due to the interposition of the lateral protrusions 30, and the gap is always in contact with the end face of the collar portion without forming a gap (see FIG. 3). ). Due to the formation of this gap flow path, air leakage and water leakage always occur from the pipe joint 1 when only the bolt 20 is temporarily fixed or hand-tightened.

  When the bolt is sufficiently tightened with a tightening tool such as a spanner, the loose flange-type pipe joint 1 pressurizes and compresses the protrusion 30 and the lip portion 24 of the elastic gasket 14, and the side surface 26 has a collar portion as shown in FIG. By closely contacting the end face, the gap flow path disappears, complete airtightness is achieved in the pipe joint 1, and leakage of air and water is completely prevented. After completing the piping work after the bolt tightening is completed, pipe fitting 1 is subject to construction failures such as forgetting to tighten bolts, forgetting how many bolts are inserted, and incomplete tightening. If this happens, air leaks and water leaks will always occur, and defective pipe connections can be detected with certainty.

  In the loose flange type pipe joint 1, the elastic gasket 14 that is relatively easy to compress and deform is brought into close contact as shown in FIG. 5, so that the tightening force by each bolt 20 only needs to withstand the tube pulling force. For this reason, the area of the contact surface with the collar portions 7 and 7 of the pipe 5 may be smaller than the conventional one, and the outer diameter of the collar portion 7 can be smaller than the conventional one. Further, the flange 8 having six bolt through holes 16 can be reduced in outer diameter and thickness as compared with the conventional flange.

  6 and 7 show a housing type pipe joint 36, and an annular protrusion 40 is provided on the outer periphery of the front part of both pipes 38 to be connected by welding or screwing. The pipe joint 36 tightens a rubber elastic gasket 42 surrounding the front ends of both pipes, a U-shaped cross-section housing 44 surrounding the elastic gasket 42 between the annular protrusions 40, 40, and both housings having substantially semicircular side surfaces. It consists of two sets of bolts and nuts (not shown) that are tightly fixed. The housing 44 is formed with annular recesses 46 on the inner peripheral portions on both sides, and the annular recesses are fitted with the pipe annular protrusions 40. On the other hand, the elastic gasket 42 has an annular side surface and has a hollow U-shaped cross section, and a pair of lip portions 48 are formed inward and downward in the cross section. The tip portions of the lip portions 48 are slightly inward in the diametrical direction from the inner peripheral surfaces of the gasket side portions.

  A plurality of inward projections 50 are formed at equal intervals in the circumferential direction on the inner circumferential surfaces of both sides of the elastic gasket 42, and the number of the projections is, for example, 12 at equal intervals in the circumferential direction. Each protrusion needs to be inward of the inner peripheral surface of the gasket 42 in the diameter direction. It is desirable that the inward projection 50 be positioned outward from the lip corner 53 in the axial direction.

  In the housing type pipe joint 36, when bolts and nuts are manually tightened for temporary fixing, as shown in FIG. 6, the lip portion 48 of the elastic gasket 42 is pushed toward the pipe outer peripheral surface by the pipe internal pressure. The outer peripheral surface keeps a gap with the inner peripheral surface of the gasket by the interposition of the inward projection 50, and the gasket always forms a gap flow path without being in close contact with the outer peripheral surface of the pipe. Due to the formation of the gap flow path, air leakage and water leakage always occur from the pipe joint 36 if only the bolts are temporarily fixed or hand-tightened.

  When the bolt is sufficiently tightened with a tightening tool such as a spanner, the housing-type pipe joint 36 compresses and compresses the protrusion 50 and the lip 48 of the elastic gasket 42 as shown in FIG. Closes to the outer peripheral surface of the pipe, the gap flow path disappears, complete airtightness is achieved in the pipe joint 36, and leakage of air and water is prevented. Pipe fittings 36 are subject to air leaks in the event of a faulty work such as forgetting to tighten bolts or incomplete tightening if an air pressure test or water pressure test is performed on all pipes after the completion of piping work after bolt tightening is completed. And water leaks can be detected reliably.

  A housing-type pipe joint 52 shown in FIG. 8 includes a housing 58 having a substantially semicircular side surface surrounding the bulging end portion 56 of the pipe 54 to be connected, and a rubber disposed around the bulging end portion inside the housing. It consists of an annular gasket 60 made of two pieces, and two sets of bolts 64 and nuts penetrating the outer extensions 62 of both housings. Both side ends of the housing 58 reach the pipe normal diameter portion beyond the pipe bulging end portion 56. The housing 58 is provided with a larger central annular recess 66 and both side recesses 68, 68. When the elastic gasket 60 is fitted in the annular recess 66 and the pipe bulging end portion 56 is fitted in the annular recess 68 on both sides, the pipes 54 and 54 can be fixedly connected by the housing-type pipe joint 52.

  A plurality of inwardly extending ridges 70 are formed in the circumferential direction on the inner peripheral surfaces of both sides of the elastic gasket 60, and transverse grooves (not shown) are formed on the ridges in the circumferential direction, for example, at regular intervals. Individually formed. Both protrusions 70 are required to be located inward of the inner peripheral surface of the gasket 60 in the diameter direction.

  In the housing-type pipe joint 52, when the bolt 64 and the nut are manually tightened for temporary fixing, as shown in FIG. 8, the elastic gasket 60 is pushed toward the pipe outer peripheral surface by the pipe internal pressure. The gap between the inner circumferential surface of the gasket is maintained by the interposition of the inwardly extending ridges 70, 70, and the gasket always forms a gap flow path without being in close contact with the outer circumferential surface of the pipe. When the bolts 64, 64 are sufficiently tightened with a tightening tool such as a spanner, the housing type pipe joint 52 is compressed and compressed with the protrusions 70, 70 of the elastic gasket 60, and the inner peripheral surface of the gasket is the pipe outer peripheral surface. By adhering to each other, the gap flow path disappears, complete airtightness is achieved in the pipe joint 52, and leakage of air and water is prevented.

DESCRIPTION OF SYMBOLS 1 Loose flange type pipe fitting 5 Pipe 8 Loose flange 12 Reinforcement ring 14 Elastic gasket 24, 24 Lip part 28 Lip valley part 30 Lateral protrusion 32 Lip side edge part

Claims (6)

  An annular elastic gasket that is installed inside a pipe joint and prevents liquid leakage from the pipe by compression and adhesion, and there are a plurality of gaskets in the circumferential direction of the gasket on the contact surface with the flange or flange end surface or pipe outer peripheral surface. The protrusions are formed and the height of each protrusion exceeds the peripheral end of the gasket, so that the pipe joint is simply attached. A gasket for a pipe joint in which there is a gap channel between the surface and the gasket, when the pipe joint is tightened, the gasket is compressed and the gap channel disappears to form a seal.   After a sealing member is interposed between the flanges or flange end surfaces of both pipes, both flanges or fitting loose flanges are joined and tightened. At this time, an annular elastic gasket and an outer peripheral side of the gasket are used as the sealing members. In a pipe joint using a metal reinforcing ring to be arranged, one or a plurality of lateral projections are formed in the circumferential direction of the gasket on the contact surface with the flange portion or the flange end surface, and the projection is a side end of the gasket in the axial direction. If an elastic gasket and a reinforcing ring are arranged between both brim parts and the pipe joint is simply attached with bolts and nuts during assembly, the gasket and brim part are interposed by the projection. If there is a gap channel between the flange end face and the pipe joint is tightened, the gasket is compressed. Gasket flange type pipe joint gap passage seal is established disappeared.   The gasket according to claim 2, wherein a plurality of lateral projections are formed at equal intervals in the circumferential direction on both side surfaces of the gasket.   In a pipe joint in which an annular elastic gasket is fitted to the ends of both pipes, a housing is covered on the gasket, and the housing is tightened with bolts and nuts, one is provided on the inner peripheral surface of the gasket at the contact surface with the outer peripheral surface of the pipe. A plurality of inward projections are formed, each projection is inward of the peripheral end of the gasket in the diametrical direction, and when assembled, the pipe joint is simply attached with a bolt and a nut. A gap channel exists between the inner peripheral surface of the gasket and the outer peripheral surface of the pipe due to the protrusions. On the other hand, when the pipe joint is tightened, the gasket is compressed and the gap channel disappears to establish a seal. Gasket for housing type fittings.   The gasket according to claim 4, wherein a plurality of inward projections are formed at equal intervals in the circumferential direction on the inner peripheral surfaces of both side portions of the gasket.   The gasket according to claim 1, 2, or 4, wherein, in the elastic gasket, instead of forming a plurality of protrusions in the circumferential direction, an annular protrusion provided with one or a plurality of transverse grooves is formed.

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