Abstract: A pipe coupling structure, configured to prevent formation of a gap between the inner peripheral surfaces of pipe elements connected together through which gap a fluid being transported may enter, includes first and second pipe elements to be connected together. The first pipe element has a first sealing portion with an acute angle defined by a first inner peripheral surface defining a hole of the first pipe element and a first annular surface extending radially outward from an end edge of the first inner peripheral surface. The second pipe element has a second sealing portion defined by a second inner peripheral surface defining a hole of the second pipe element and a second annular surface extending radially outward from an end edge of the second inner peripheral surface. The first and second pipe elements are connected together, with the first and second end edges abutted against each other.

Abstract: A pipe coupling structure, configured to prevent formation of a gap between the inner peripheral surfaces of pipe elements connected together through which gap a fluid being transported may enter, includes first and second pipe elements to be connected together. The first pipe element has a first sealing portion with an acute angle defined by a first inner peripheral surface defining a hole of the first pipe element and a first annular surface extending radially outward from an end edge of the first inner peripheral surface. The second pipe element has a second sealing portion defined by a second inner peripheral surface defining a hole of the second pipe element and a second annular surface extending radially outward from an end edge of the second inner peripheral surface. The first and second pipe elements are connected together, with the first and second end edges abutted against each other.

Abstract: A metal seal ring by which conduits are hermetically engaged by a pressure in accordance with a fluid pressure. The metal seal ring is comprised of a first annular seal surface, a second annular seal surface a pressure receiving surface which is formed between a first and second seal surfaces and which defines an annular recessed portion, and an annular seal portion comprised of a first seal portion and a second seal portion which are both elastically deformable and both formed between the annular recessed portion and the second seal surface. Additionally, an annular seal ring main body is provided on the radially outer side of the seal portion to prevent the first and second flanges from moving closer to the metal seal ring in the axial direction.

Abstract: Disclosed is a metal seal ring by which conduits are hermetically engaged by a pressure in accordance with a fluid pressure. The metal seal ring is comprised of a first annular seal surface (12a) configured so as to be in contact with a first flange, a second annular seal surface (12b) configured so as to be in contact with a second flange, a pressure receiving surface (12f) which is formed between the first and second seal surfaces and which defines an annular recessed portion (12e) which is radially inwardly open, and an annular seal portion (12) comprised of a first seal portion (12A) which is elastically deformable and formed between the annular recessed portion (12e) and the first seal surface (12a) and a second seal portion (12B) which is elastically deformable and formed between the annular recessed portion (12e) and the second seal surface (12b).