Centrifugal pumps

1,165,884. Centrifugal pumps. NEWAGE LYON Ltd. Nov. 7, 1966 [Dec. 3, 1965], No.51489/65. Heading F1C. In a self-priming centrifugal pump a portion of the liquid discharged therefrom is trapped in a priming chamber 13, Fig. 1, for subsequent, flow through perforations or slots 31 and tubes 30, 32 to a seal chamber 17 for cooling the shaft seal 18. Thereafter the liquid returns through an annular gap 35 to the entrainment region of backwardly-curved impeller vanes 40 to provide the self-priming characteristic. The gap 35 is formed between the impeller hub 21 and a stationary wear plate 24 arranged opposite a similar wear plate 23. In a modification, Fig. 2 (not shown), the impeller has a back plate with arcuate slots (44) therethrough for the return flow.