GB1025384A - Improvements in or relating to seals - Google Patents

Abstract

1,025,384. Seals. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 4, 1963 [April 25, 1962], No. 15700/62. Heading F2B. A sealing device for controlling leakage of fluid between a casing and a rotatable shaft or collar secured to the shaft comprises a soft packing ring held by means of a jacket or an open-cage-like member, a sealing member between the casing and the jacket or cagelike member, and a connection for applying pressure medium to the packing ring to vary its sealing contact with the shaft or collar. In Fig. 1, the packing ring 1 is held in a non-rotatable jacket 3 of plastic material contained in a recess 4 in a stationary casing 5 and floatingly supported by a spring 6. The fluid being sealed enters the chamber 4 and acts on to the jacket to press the packing ring 1 against a shaft 2. In a modification, Fig. 2 (not shown), the spring is dispensed with and the jacket 3 is sealed on both sides to the casing, pressure medium, which may be the fluid being sealed or fluid under manual control, being supplied to the recess in the casing. In a further modification, Fig. 3 (not shown), the packing ring 1 is normally loose on the shaft 2 and is forced thereon, when required, by supplying fluid to the recess 4 by means of a pump 7, the pressure being controlled by a relief valve 8. In another embodiment, Fig. 4 (not shown), two spring-loaded packing rings 1 are held by an open-cage-like member 9 to which grease is supplied from an hydraulic intensifier 10. In a modification, Fig. 5 (not shown), the spring 6 is dispensed with and a cage-like member 9 is provided for each packing ring, a part of each member 9 forming a bearing surface against the shaft 1. In a further modification, Fig. 6 (not shown), the middle spring loading the rings is also dispensed with and the two cages are joined by a waist which forms a bearing against the shaft. In a further embodiment, Fig. 7 (not shown), a mechanical sealing arrangement is formed by two soft packing rings 1 loaded against a collar 11 on the shaft by grease supplied to a recess 4 in an axially floating member 13 which is movable against a spring 6 so as to act on the packing rings 1 via the cagelike member 9. A plastic pad 12 is carried by the member 13 to engage with the collar 11 when the packing rings 1 are worn. In a modification, Fig. 8 (not shown), only one packing ring 1 is provided and the cage-like member is an integral part of the member 13. In a further modification, Fig. 9 (not shown), the mechanical sealing arrangement is normally effective but in the event of its failure or replacement, a jacket-type sealing device 1, 3 comes into operation.