Sealing material, pressing ring, coupling, and valve

摘要

The present invention involves: forming a first projection (19) in the outer-circumferential section of a valve part (18); forming a second projection (20) in the receiving-port far-end section of the valve part (18); forming a tapered part (28) which decreases in diameter from the inner circumference of the heel part (17) toward the inner circumference of the second projection (20); forming a third projection (21) on the tapered part (28) so as to project to the inside in the radial direction; forming the inner diameter of the third projection (21) so as to be smaller than the outer diameter of the insertion port and larger than the inner diameter of the second projection (20); forming the angle direction (G) of the tapered part (28) in a manner such that a first dimension (B) in the opposite angle direction from the first projection (19) to the third projection (21) is smaller than a second dimension (C) in the radial direction (A) from the first projection (19) to the second projection (20); and compressing the interval between the first projection (19) and the third projection (21) in the radial direction (A), resulting in the retention of watertightness between the receiving port and the insertion port.