GB1094058A - High pressure fluid seal with biasing action - Google Patents

Abstract

1,094,058. Mechanical seals. SEALOL Inc. June 30, 1965, No. 27647/65. Heading F2B. A seal for controlling the leakage of fluid along a rotatable shaft is formed by a sealing ring and a mating ring which are axially movable relative to each other, the axial dimensions of the sealing ring being such that at least at one face of the sealing ring parallel to the sealing face the fluid pressure undergoes a pressure drop so that the effective pressure on the sealing ring is sufficient to force the sealing face towards the mating face but insufficient to prevent some leakage therebetween. As shown, a sealing ring 50 is axially movable by the pressure of fluid in a pump housing 10 and both the end faces cooperate with mating faces on rings 25 and 27 to control the passage of fluid therebetween, the rings 25, 27 being secured to the shaft 18 by nut 31 and spacing collar 26. The fluid passes through a restricted, passage A, an unrestricted passage B and a restricted passage C towards an outlet 22A, pressure-drops occurring through both of the restricted passages. The passage A is 0À0009 inch wide and the passage C is 0.0002 inch wide, the gap at the sealing face being 0À0001 inch. A knife edge 40 on the sealing ring 50 allows the ring to align itself with the ring 27. In Fig. 3 (not shown), the fluid travels in the direction of the arrow between the sealing face of the ring (50A) and the mating face of the ring (27A) which is screwthreaded on to the shaft. In Fig. 4 (not shown) the fluid flows through restricted passage between the mating ring (25A) and the sealing ring (50B) which is mounted for axial movement on a cylindrical portion (21C) of the housing cover (21Z). Fig. 5 (not shown), is a modification of Fig. 4 and illustrates the knife edge on the sealing ring (50C) instead of on the cylindrical portion of the cover. In Fig. 6 (not shown), the sealing ring (50D) is urged into engagement with the mating ring (25D) by a bellows (100) as well as the fluid pressure. In Fig. 7 (not shown), the sealing ring (50E) is held against rotation by a pin (102) on a cylindrield portion of the housing cover (21X) and is urged into engagement by a coil spring (100A); the passage between the sealing ring and cover may also be restricted. -In, Fig. 8 (not shown), the sealing ring (50F) is driven by a pin (102F) on the shaft and is slidably mounted so as to cooperate with mating rings (105), (25F) secured to the housing. Restricted passages are provided at each end of the sealing ring. Fig. 9 (not shown) is a modification of Fig. 8 wherein only one end of the sealing ring forms part of a restricted passage.. In Fig. 10 (not shown), both the sealing ring (50H) and mating ring (27H) are slidably-mounted and co-operate with each other to provide a restricted passage, the fluid travelling in the direction of the arrow. In a further embodiment, Fig. 11 (not shown), the sealing ring (50L) is urged by bellows (177) and fluid pressure into engagement with a mating ring (27L) on the shaft. Reference has been directed by the Comptroller to Specification 1,012,085.