GB332465A - Centrifugal pumps rendered self-priming by means of their gap water - Google Patents

Abstract

332,465. Pfleiderer, C. July 16, 1929, [Convention date]. Starting, facilitating; balancing moving parts.- In a centrifugal pump the energy of the water passing through the gap between the impeller and the casing, is used to effect de-aeration by means of a jet apparatus consisting of inlet and receiver nozzles. On the inlet side of the impeller a is attached the wall b which forms a moving side of an annular nozzle, the other side c of which is stationary. The water from the gap passes from the nozzle in the form of a thin sheet, through the receiving nozzle d and accumulates in the vessel f. Any air escapes through the vent i and the water is returned to the suction chamber by the pipe, g which contains an automatic valve h. A similar arrangement can be used to balance axial thrust. The moving wall b of the nozzle is attached to the impeller as shown in Fig. 2 and the stationary wall c forms a throttling space H with the moving part. If the rotor moves to the left the nozzle widens and the pressure on the movable wall b diminishes. In a modification the pump is provided with a gap which varies with the axial position of the impeller and the nozzle takes the form of a separate jet pump. The water is deaerated by this apparatus and returned to the suction of the centrifugal pump. In another modification the nozzle is directed inwards towards the axis. Guide vanes k are mounted on the stationary wall c of the nozzle to impart the desired direction of flow to the outgoing water. The nozzle may be widened by the axial displacement of the wall c; this is effected by the rotation of the wheel l which causes the rotation of the wall c and its axial movement by means of a screw thread.