GB1244757A - Rotary pumps - Google Patents

Abstract

1,244,757. Rotary pumps. K, MœLLER. Oct.10, 1968 [Oct.25, 1967], No.48067/68. Heading F1F. A rotary pump comprises two discs carried by the pump shafts to slide on the side walls of a substantially cylindrical housing; sector-shaped plates arranged between the two discs and extending from the shaft or a hub fixed thereon as far as the cylindrical inner wall of the housing and filling the sector of the housing between an outlet opening and an inlet opening; and recesses in the shaft or hub and in the two discs and arranged to be engaged by that plate which is situated before the inlet opening and to be disengaged when that plate reaches the outlet opening; the inner wall of the housing having a smaller radius corresponding to the depth of the recesses in the sector between the inlet opening and the outlet opening. The pump shaft 7 carries a hub 8 and two spring-pressed discs 9, 10, with sector-shaped plates 11 stacked between the discs. Recesses 12, 13 are formed in the hub 8 and the discs 9, 10 respectively. When the rotation of the shaft brings one set of recesses 12, 13 adjacent an inlet port 5 as shown, that plate 11<SP>1</SP> which at that time is situated at the top before the inlet port is urged by its own weight or by air pressure or oil pressure or, as shown by springs 16 acting on a slide 31, radially inwards into engagement with the recesses. The plate is then carried around a portion 14 of the housing 1 between the inlet port 5 and an outlet port 6, as shown at 11<SP>11</SP>, the portion 14 being of reduced radius to compensate for the retraction of the plate into the recesses 12, 13. Gas or liquid is thereby forced from the inlet port 5 to the outlet port 6. On reaching the end of the portion 14, the plate is disengaged from the recesses 12, 13 by centrifugal force and by the effect of the shape of the recesses and joins the stack of stationary plates 11 extending from the outlet port 6 to the inlet port 5. Each time one plate 11<SP>1</SP> is transported, the fluid-pressure exerted on the last plate of the stack, which may be assisted by frictional drag exerted by the discs 9, 10, moves the stack around by the extent of one plate. Channels 30 may be provided in the non-pumping sector of the housing wall 4 to reduce the frictional area and to collect lubricant. The plates 11 may be hollow and may be of nylon. The recesses 13 or the lateral projections 18 of the plates 11 which engage the recesses may have resilient bearing surfaces. In the case of a vacuum pump, each disengaged plate 11<SP>11</SP> tends to strike heavily against the stack of plates 11. To avoid this, the plate 11<SP>11</SP> can be braked by an air or gas cushion afforded by a space provided between the rear plate 11 and the outlet port 6, air or gas thereby conveyed past the outlet port being discharged from the space to the outlet through narrow ducts.