GB946494A - Mechanical seals for rotating shafts - Google Patents

Abstract

946,494. Stuffing-box substitutes. WORTHINGTON CORPORATION. Sept. 19, 1961 [Nov. 28, 1960], No. 33468/61. Heading F2B. Sealing means for a rotary pump shaft 9 includes a high-pressure mechanical seal comprising a rotatable ring 15 and a non-rotatable ring 20 pivotally mounted for universal movement and urged axially toward the ring 15 to maintain a predetermined fluid film therebetween by fluid leaking across the seal, means being provided to control the pressure of such leakage fluid. A seal housing 2 is divided into inner and outer seal chambers 7 and 8 respectively housing a low pressure mechanical seal including a rotatable ring 14 and the highpressure seal comprising the rings 15 and 20. The ring 20 has an extension 37 sealingly mounted between 0-rings 40 and 41, Fig. 3, respectively housed in flanges 31 and 32 of sleeves 21 and 33 respectively both secured to the housing 2. The sleeve 21 is surrounded by spaced concentric sleeves 24 and 60 and the rings 14 and 15 are axially spaced by a sleeve 17 which passes with clearance through the ring 20 and the sleeve 33. A piston 39 secured to the extension 37 is sealed to the sleeve 60 by an 0-ring 63. The ring 20 is prevented from rotating by a pin 65 and held against the ring 15 when the pump is not operating by a spring 66. The sealing face of the ring 20 has circumferential grooves 45 and 46, Fig. 4, defining a high-pressure land 50 and a lowpressure land 49 and radial grooves 51 defining pads 52a, 52b, &c. Passages 44 in the ring 20 communicate with the piston space 43 and via inlets 47 with the groove 45. The space 57 in front of the piston 59 is vented to atmosphere via passages 48, 49, chamber 26 and port 27. The piston space 43 communicates with a reservoir 72, Fig. 6, by port 70, pipe 71 and orifice 76 or 77 which may be fixed or variable; the orifice 77 being used when the pump is not running. Fluid collected in the reservoir 72 may be returned by a pump 81. In operation, the pressure of the leakage fluid in the space 43 is controlled by the orifice 76 to provide a film of predetermined thickness between the rings 15 and 20. Any fluid leaking past the land 49 of ring 20 escapes through clearances 54 and 36 to the chamber 7 where it is prevented from leaking along the shaft by the low pressure seal and passes to the reservoir 72 through port 82 and pipe 83. Specification 946,494 is referred to.