Patent ID: 8491017
Filing Date: 2013-07-23
Classification: F16L

Abstract:
1. A fitting structure comprising: a pair of connection pipes; a flange formed at a leading end of each of the connection pipes, each flange comprising an annular projection, a recessed portion on an outer surface of the flange at a leading end of the flange, a non-recessed portion on the outer surface of the flange, and a step between the recessed portion and the non-recessed portion; a flat ring-shaped metal gasket constructed and arranged to be in contact with each projection on opposite sides when the flanges are opposite to each other; a holder constructed and arranged to hold the metal gasket, the holder comprising a tubular section within which the metal gasket is housed and a claw-shaped engagement section extending radially inward from one end portion of the tubular section, the holder being held by one of the connection pipes such that when the metal gasket is housed within the tubular section, the claw-shaped engagement section is in engagement with at least a part of the metal gasket, and the tubular section is fitted on the recessed portion of the connection pipe; a center ring mountable to surround and contact outer peripheries of both non-recessed portions of the flanges when the flanges of each of the pair of connection pipes are opposite to each other across the metal gasket; a clamp ring comprising three segments arranged in sequence and coupled such that adjacent segments are pivotally attached to one another, and such that the three segments define a ring shape constructed and arranged to cover and hold outer peripheries of the flanges when the flanges are disposed opposite to each other across the metal gasket and when a segment of the three segments positioned at one end and a segment positioned at another end are fixed to each other by a fastening member, a first interspace allowing the center ring to fit on the non-recessed portions of both flanges without coming into contact with the holder, the first interspace being formed between an outer surface of the holder and an inner surface of the center ring because of a difference between an inside diameter of the center ring and an outer diameter of the holder, and a second interspace allowing the clamp ring to contract when the segment positioned at the one end and the segment positioned at the another end are brought into close proximity with each other without coming into contact with the center ring, the second interspace being formed between an outer surface of the center ring and an inner surface of the clamp ring because of a difference between an outside diameter of the center ring and an inside diameter of the clamp ring which defines the ring shape when the segment positioned at the one end and the segment positioned at the another end are fixed to each other by the fastening member, wherein each flange has a slope which is downwardly inclined from the outer periphery of each flange respectively toward a side opposite to the leading end, each segment of the clamp ring has a corresponding slope respectively corresponding to the slope of said each flange on an inner periphery of each segment, and an inside diameter of the tubular section of the holder and an outside diameter of the metal gasket are equal to each other and are smaller than an inside diameter of the center ring.