SWIVEL SEAL CONSTRUCTION

摘要

The invention relates to a swivel (40) with an outer (41) and inner annular wall (42). A toroïdal chamber (44) is defined between the outer and inner walls and opposing peripheral faces of the walls define an upper (45) and lower gap (52) extending respectively upwardly and downwardly from the toroïdal chamber. The upper and/or lower gap has a first section (46) extending axially, a second section (47) transvers to the first section (46) and a third section (48) extending substantially parallel to the first section (46). A seal (50, 51) is placed in the second (47) or the third (48) section of the upper and/or lower gap (45, 52), the seal having two flexible legs (61, 62) arranged in a generally u-shaped or v-shaped orientation. The gap near the area of the seal being filled with a sealing fluid during use, a fluid duct (56), extending through the outer or inner annular wall (41, 42) to the gap (45, 52) and having an outlet in the gap section between the seal (50, 51) and the toroïdal chamber (44), and means for transporting flushing fluid under pressure through the duct (56) to the toroïdal chamber. The invention is characterised in that the seal (50, 51) is placed in the second gap section (47), or in the third gap section (48) at a position (H) below the upper or lower end part of the first gap section (46), the outlet of the fluid duct (56) being placed in the third gap section (48) or in the second gap section (47). In this way ingress of gas upwardly, and water downwardly towards to the primary seals can be prevented, the water and gas being periodically flushed into the toroïdal chamber.