TANDEM DOUBLE SEAL FOR NUCLEAR POWER PLANT

摘要

The present invention provides a floating ring mechanical seal wherein the sealing surface of the floating ring appropriately contacts the sealing surface of a counterpart seal and exhibits excellent sealing capability even under conditions in which the pressure or temperature of a fluid to be sealed increases or decreases significantly. The present invention pertains to a floating ring mechanical seal wherein a floating ring (5) is compressed and held between a rotary ring (4) and a stationary ring (2), with the stationary ring (2) configured as an cylindrical body having an L-shaped cross section and comprising a thick annular main body part (21) one end of which contacts the floating ring (5), and a thin cylindrical retaining part (22) extending in the axial direction from the inner circumferential edge of the other end of the main body part, and with an O-ring (7a) interposed between a seal case (1) and the retaining part (22) at the inner circumferential part of the seal case, and fitted and retained so as to be capable of moving in the axial direction. In addition, the stationary ring (2) is formed of a metal material having a Young's modulus and/or a thermal expansion coefficient approximately the same as that of the material forming the floating ring (5).