Patent GB-218201-A (GB)
Title: Improvements in or relating to rotary pumps and the like
IPC: F16J15/34
Filed: 1923-12-22
Abstract: 218,201. Carrier, W. H. Dec. 22, 1923. Balancing moving parts; leakagepreventing devices.-The opening through which the rotary shaft passes out of the pump or compressor casing is closed without substantial friction while the pump is running by means of a sealing liquid under pressure, and is closed by a valve when the pump is at rest. Liquid under pressure is also used to balance the end thrust. The rotor shaft C is carried by bearings D, Fig. 2, D', Fig. 3, and the end thrust produced causes the shaft to move slightly to the left with the arrangement shown. Attached to the shaft is a collar 10, Fig. 2, facing a stationary member 11 which limits the movement of the shaft and which forms one end of a pressure chamber 12. Liquid, preferably lubricating oil, is supplied to this chamber and acts on the collar 10 to oppose the end thrust of the pump and escapes between the members 10, 11 into the chamber 14. The liquid pressure is maintained by the pump 29 which is driven through gearing from the shaft C and therefore the pressure on the collar 10 continues as long as the compressor is working. The liquid is supplied through the pipe 32 and is conveyed by the pipe 37 from the chamber 14 to the oil reservoir 26. The end of the shaft shown in Fig. 3 projects through an opening 16 in the casing with packing rings 74. A sealing chamber 17 with an annular valve plate 18 on the shaft is provided at this end, and when the compressor is not running the valve plate 18 is seated against the bushing 19. The movement of the plate 18 away from the bushing 19, is limited by the engagement of the collar 10 and member 11. The passage round the plate 18 is very small and' passages 20, 20<a> lead to the spaces on each side of the plate, the latter passage 20a to the bottom of a closed oil container 22 and a pipe 23 leads from the passage 20 to the upper part of the container. The pump 29 takes oil from the reservoir 26 and supplies the container under pressure through the pipe 31; the oil passes through the pipes 21, 23 to form the seal on both sides of the valve plate 18. Oil from the chamber 17 passes through the bushing 33 to the chamber 34 from whence it escapes through the pipe 35 to the trap 36 which is controlled by a float valve 39. A pipe 41 conveys oil from the chamber 42 to the reservoir 26. The oil flowing through the passages 20, 20<a> forms the liquid seal when the compressor is working, but when this stops the pipe 23 serves as a vent pipe for the container 22, and oil runs down through the pipe 21 and forms a film over the plate 18 and its seat on the bushing 19, to assist the valve in making a gas tight closure. A centrifugal device in which weights fly out to permit the axial movement due to the end thrust may be employed, the inward movement of the weights as the compressor stops being utilized to return the shaft to the position in which the plate 18 rests on the bushing 19. Or, the arrangement shown in Fig. 2 may be used. A coil spring 60 rests between a fixed abutment 61 on the shaft C and a sliding sleeve 62 with a flange engaging a ball thrust bearing 63 which is held against the flange of an inner sleeve 64 adjustably secured on the end of the shaft. To prevent leakage of oil from the bearings into the pump along the shaft, a sleeve 65 with internal circumferential grooves 66 is arranged over narrower grooves 67. Leakage oil is thrown by centrifugal force into the grooves 66 and is returned to the oil reservoir bv the passage 68. Absorbent material may be placed in the grooves to hold the oil when the shaft is not running.