Abstract: An outer ring of a clamp-type joint for vacuum apparatus is disclosed. The joint includes a base forming an outer circumferential side and a pair of brims respectively extending from the top and bottom of the base toward the center axis of the joint, the inner side of the brims on which the brims come into contact with the O-ring being in the form of a convex sector, of which the arc faces the O-ring. The radius r of the circle forming the sector is 0.6-2.5 mm and the thickness (t0) satisfies the following formula: t1?0.2?t0?t1+0.4. In the formula, t1 is a thickness (mm) of the center ring at the point at which the center ring engages with the O-ring. The clamp-type joint can exhibit stable sealing performance at a high temperature of 250° C. or more without cracking of the O-ring.

Abstract: An O-ring used in a clamp-type joint for a vacuum apparatus, which engages with a concave groove in the outer circumference edge of the center ring and is sandwiched by an outer ring having a U-shaped outer circumference, wherein the radius of the circular arc in the cross-section on the side coming into contact with the outer ring is smaller than the radius of the circular arc in the cross-section on the axial side of the joint. A clamp-type joint for the vacuum apparatus which can exhibit stable sealing performance at a high temperature of 200° C. or more without cracking of the O-ring, as well as an outer ring and O-ring used with the clamp-type joint are also provided.

Abstract: A ring-shaped metal gasket 10 in which a metallic ring 10b is fitted to at least one of two valley portions 11b, 12b in the ring-shaped metal gasket 10a. The metal gasket 10 is free of plastic deformation even if a large compressive load is applied thereto and difficult to undergo fatigue destruction. Even if a difference in pressure between a fluid side to be sealed and a non-fluid side on the opposite side is high, the gasket is hard to damage.

Abstract: An O-ring 3 used in a clamp-type joint 10 for vacuum apparatus, which engages with a concave groove 21 in the outer circumference edge of the center ring 2 and is sandwiched by an outer ring 5 having a U-shaped outer circumference, characterized in that the diameter of the circular arc in the cross-section on the side coming into contact with the outer ring 5 is smaller than the diameter of the circular arc in the cross-section on the axial side of the joint. A clamp-type joint for vacuum apparatus which can exhibit stable sealing performance at a high temperature of 200° C. or more without cracking of the O-ring, as well as an outer ring and O-ring used with the clamp-type joint are provided.

Abstract: An outer ring of a clamp-type joint for vacuum apparatus is disclosed. The joint comprises a base forming an outer circumferential side and a pair of brims respectively extending from the top and bottom of the base toward the center axis of the joint, the inner side of the brims on which the brims come into contact with the O-ring being in the form of a convex sector, of which the arc faces the O-ring. The radius r of the circle forming the sector is 0.6-2.5 mm and the thickness (t0) satisfies the following formula: t1?0.2?t0?t1+0.4, wherein t1 is a thickness (mm) of the center ring at the point at which the center ring engages with the O-ring. A clamp-type joint for vacuum apparatus which can exhibit stable sealing performance at a high temperature of 250° C. or more without cracking of the O-ring, as well as an outer ring and O-ring used with the clamp-type joint are provided.

Abstract: The present invention provides a combination metal gasket that is formed by fitting a ring-shaped metal base elastic structure in at least one trough portion of two trough portions of a ring-shaped metal gasket that has an S-shaped longitudinal cross section. The combination metal gasket does not demonstrate the plastic deformation even when a large compressive load is applied and is not likely to be destroyed even when a pressure of a fluid being sealed is high; that is, stable sealing properties are exhibited.

Abstract: To obtain a gasket holding device which is unlikely to slip out of a bolt and facilitates mounting of the bolt thereon, a bolt mounting hole made in a metal plate constituting the gasket holding device is provided with an engaging portion which engages the bolt. This engaging portion is formed by processing part of the metal plate on the bolt mounting hole thinly such that it is elastically deformed and projected in between a crest and a root of the bolt.

Abstract: In order to provide a gasket which can be repeatedly used over a temperature range in which a rubber gasket cannot be used, which does not have any risk of damaging a flange, and which can follow the change of the distance between flanges, a gasket is constructed in such a way that two metallic coned disc springs each of which has a circulation opening for a fluid in a central portion and each of which is formed into a seal surface in which an outer peripheral portion with respect to the circulation opening rises having an arc-like curved surface are combined while being oppositely directed and have outer diameter peripheral edge portions which are welded and fixed so that by tightening flanges, repulsive force of the two coned disc springs concentratedly affects the seal surfaces consisting of the arc-like curved surfaces, and a tight fluid seal is formed between the flange surfaces.

Abstract: An annular-shaped metal gasket, which can reduce a tightening force necessary to a seal and easily manage the manufacturability and the characteristics thereof, the metal gasket, in an annular-shaped metal gasket having a cross section provided with an outer circumferential opening and formed in one of a laterally U-shape, voids are formed to the innermost circumferential portions on the two confronting flat sealing surfaces of the metal gasket that are in contact with opponent surfaces, each void having a width equal to or more than 40% of the central wall thickness t0 of a bight section and a height equal to or more than 5% of the height H of the gasket, wherein the cross section of the gasket is formed in a tuning-fork shape. A tightening force necessary to the seal can be reduced by forming the cross section of the metal gasket in the tuning-fork shape and providing the voids with the surfaces of the metal gasket in contact with the opponent surfaces.

Abstract: To provide an annular-shaped metal gasket, which can reduce a tightening force necessary to a seal and easily manage the manufacturability and the characteristics thereof, the metal gasket, in an annular-shaped metal gasket having a cross section provided with an outer circumferential opening and formed in one of a laterally U-shape, voids are formed to the innermost circumferential portions on the two confronting flat sealing surfaces of the metal gasket that are in contact with opponent surfaces, each void having a width equal to or more than 40% of the central wall thickness t0 of the gasket and a height equal to or more than 5% of the height H of the gasket, wherein the cross section of the gasket is formed in a tuning-fork shape. A tightening force necessary to the seal can be reduced by forming the cross section of the metal gasket in the tuning-fork shape and providing the voids with the surfaces of the metal gasket in contact with the opponent surfaces.

Abstract: In order to provide a ring-shaped metal gasket that can secure a uniform sealing property over the entire surfaces of flanges regardless of the position of a bolt and a nut for tightening a clamp, a ring-shaped metal gasket is composed of an annular main body having a square cross section, a pair of annular arm portions projecting circumferentially outwardly of the annular main body in a bugle state at a predetermined angle, and an annular projecting portion bulging circumferentially inwardly with a height larger than the axial height of the annular main body. The annular projection portion acts as a positioning means. When a flange portion is tightened by a wedge action achieved by tightening a clamp, the pair of annular arm portions are elastically deformed and come into pressure contact with the flange surfaces by the elastic repulsive force thereof.

Abstract: The present invention provides a combination metal gasket that is formed by fitting a ring-shaped metal base elastic structure in at least one trough portion of two trough portions of a ring-shaped metal gasket that has an S-shaped longitudinal cross section. The combination metal gasket does not demonstrate the plastic deformation even when a large compressive load is applied and is not likely to be destroyed even when a pressure of a fluid being sealed is high; that is, stable sealing properties are exhibited.

Abstract: In order to provide a gasket which can be repeatedly used over a temperature range in which a rubber gasket cannot be used, which does not have any risk of damaging a flange, and which can follow the change of the distance between flanges, a gasket is constructed in such a way that two metallic coned disc springs each of which has a circulation opening for a fluid in a central portion and each of which is formed into a seal surface in which an outer peripheral portion with respect to the circulation opening rises having an arc-like curved surface are combined while being oppositely directed and have outer diameter peripheral edge portions which are welded and fixed so that by tightening flanges, repulsive force of the two coned disc springs concentratedly affects the seal surfaces consisting of the arc-like curved surfaces, and a tight fluid seal is formed between the flange surfaces.

Abstract: To obtain a gasket holding device which is unlikely to slip out of a bolt and facilitates mounting of the bolt thereon, a bolt mounting hole made in a metal plate constituting the gasket holding device is provided with an engaging portion which engages the bolt. This engaging portion is formed by processing part of the metal plate on the bolt mounting hole thinly such that it is elastically deformed and projected in between a crest and a root of the bolt.

Abstract: A metal C-shaped ring gasket is constructed so that a satisfactory sealing property can be obtained even with a low clamping pressure. The metal C-shaped ring gasket is made of an austenite stainless steel and constructed so as to have a superficial roughness below 0.2 &mgr;m Ra and a superficial hardness below 230 Hv by electrolytic polishing.

Abstract: In order to provide a spiral wound type gasket, in which centering of the gasket body is easy and a good sealing property at a low superficial pressure can be obtained, the spiral wound type gasket is constructed by winding a metal hoop member having an approximately V-shaped cross section and a filler member in a spiral, superposed on each other. In this gasket, an extremity bent portion of the V shape of the hoop member is directed towards the inner peripheral side and in this way it is possible to obtain a good centering and to prevent bulge-out of the filler member towards the interior of the pipe.

Abstract: In order to obtain an extremely good gas sealing property, in a spiral gasket, in which a metal hoop material and a filler material formed approximately in a V-shape in the cross-section are wound in a spiral, superposed on each other, only the hoop material is wound in a spiral without filler material by at least 5 turns at each of the beginning of winding on the inner side and the end of winding on the outer side. In this case there are disposed at least 4 portions fixed by welding at each of the beginning and the end of winding at positions, where the inner periphery and the outer periphery are divided with equal intervals on the inner and the outer side of the gasket body, respectively.