Patent GB-861705-A (GB)
Title: Improvements in or relating to rotary shaft seals
IPC: F16J15/34
Filed: 1957-04-18
Abstract: 861,705. Stuffing-box substitutes. LA BOUR, H. E. April 18, 1957 [Dec. 7, 1956], No. 12660/57. Addition to 854,526. Class 122 (5). A seal for a vertical rotary shaft 5, particularly a centrifugal pump-shaft, comprises a first sealing ring 60 urged by a spring 87 into engagement with a second sealing-ring 65 rotatable with the shaft, an annular reservoir around the shaft for holding lubricant out of contact with the sealing-rings and means for feeding lubricant from the reservoir to the engaging surfaces of the sealing-rings. The sealing ring 65, preferably of carbon or graphite, is tightly fitted in a collar 66 secured to the shaft by a pin 69 and sealed to the shaft by an O-ring 72. A pin 68 projecting from the collar 66 into the ring 65 prevents relative rotation between the two parts. The sealing-ring or sleeve 60 is surrounded by the hub 50 of a guide-member 49, Fig. 15, fixed to a plate 6 secured to a seal housing 3 connected to the pump body 4 and the sleeve is axially slidably guided in a flange 58 of the plate 6 and in a flange 52 at the upper end of the hub 50 and is sealed by a resilient packing-ring 55 compressed by a spring 53 between the flange 52 and a metal ring 54. The sleeve 60 is preferably of metal or ceramic. A loading-ring 79 slidable on the hub 50 is urged downwardly by the spring 87 and has arms 85 that engage in notches 76 in the upper end of the sleeve 60, see Fig. 14, and thereby urge the sleeve into contact with the sealing-ring 65. The arms 85 also engage notches 77, Fig. 15, in the member 49 thus preventing rotation of the sleeve 60, the notches 77 having a greater depth than the notches 76, thereby permitting downward movement of the ring 79 and the sleeve 60 as wear occurs. A lubricant elevator 89 having a depending flange 94 provided in its inner surface with inclined ribs 95, Fig. 5, is secured to the shaft above the member 49 which with the housing 3 forms an annular reservoir vented to atmosphere at 97<SP>1</SP> and supplied with lubricant maintained at a level slightly above the lower end of the flange 94. In operation, lubricant is pumped from the reservoir by the ribs 95 on to the shaft 5 above the sleeve 60 whence it flows by gravity to fill the space between the sealing- ring 65 and the shaft and thus lubricate the engaging surfaces of the sleeve and ring. To facilitate the upward and inward movement of the lubricant helical grooves 104 and inclined grooves 105, Fig. 10, are provided on the outer surface and arms 85, respectively, of the member 79. Openings 96, 97 are provided in the elevator 89 to prevent syphoning of lubricant into the pump should the seal fail. The seal lubricant is cooled by water circulated through a cavity 44 in the housing 5. In the arrangement shown in Fig. 1 water is used as the seal lubricant and it is introduced through a pipe into the housing 3 and maintained at the desired level by a dam 48 in the outlet pipe fitting 47. The shaft bearings 19, 30 are lubricated by oil supplied by a solenoid-operated lubricator 27 and drained through a pipe 38, leakage of bearing-oil along the shaft being prevented by an oil seal 40. If it is desired to use oil as the seal lubricant, the water inlet is plugged and the fitting 47 replaced by a constant level oiler. In a modification, the bearing oil is also used as the seal lubricant, the passage 37 being plugged and the oil seal 40 omitted. In another modification, the shaft bearings are lubricated by grease and fitting 47 is replaced by a constant level oiler.