GB1148915A - Seals between relatively rotatable parts - Google Patents

Abstract

1,148,915. Seals. BRISTOL SIDDELEY ENGINES Ltd. 27 July, 1966 [28 July, 1965], No. 32302/65. Heading F2B. [Also in Division F1] In a turbodrill a lubricated bearing 12 for the motor shaft 11 is sealed by a face seal comprising a rotary sealing element 29 and a non- rotary sealing element 30 sealed to the shaft 11 and the motor casing 10 respectively and urged into facial sealing contact with one another and a further seal 110 is provided between the shaft and the casing on the drilling mud side of the face seal, the space between the two seals being filled with oil maintained at a pressure substantially equal to that of the drilling mud outside the casing 10. The element 29 is slidably mounted on a sleeve 20 slidable on a coupling member 13 splined to the shaft 11, the sleeve and the element being rotated with the shaft by pins 25 and 33 respectively and sealing O-rings 27 and 35 being provided in the sleeves. The element 30 is slidably housed in a fixed sleeve 17 and sealed thereto by an O-ring 40. Springs 37 and 44 urge the sealing faces 31 of elements 29 and 30 into contact with each other. A lip seal member 110 seals against the sleeve 20 and a sleeve 109 clamped to the casing 10. A drill collar 120, Fig. 2, is screwed into the coupling member 13 and sealed thereto by O-rings 71, 72 and a spigot member 124 located between the collar 120 and the shaft 11 carries a frustoconical flexible diaphragm 122 which divides a space between the spigot member and the collar into two separate chambers 83 and 84. The chamber 83 communicates through holes 75 and 76 with the drilling mud in the borehole and the chamber 84 communicates through passages 78 and 79 and splines 14 with a cavity 80 connected by holes 81 and 82 to a cavity 85 leading to the clearance space 29a between the sealing elements and the sleeve 17. The space formed by cavities 80 and 85 and chamber 84 and the interconnecting passages is filled with oil which is pressurized by the drilling mud acting on the diaphragm 122 and thus the pressures on each side of the seal member 110 are substantially equal. The lubricating oil in the bearing space 86 is supplied from a reservoir (133), Fig. 3 (not shown) having a wall constituted by one side of a flexible diaphragm (134) subjected on its other side to drilling mud by-passing the turbine and flowing through a pressure reducer (137) whereby the lubricating oil pressure is slightly above the drilling mud pressure downstream of the turbine.