Pumps

Abstract

A regenerative pump comprises a housing (1), an impeller (5) within the housing (1) having a plurality of vanes (13) spaced angularly around the axis of rotation of the impeller (5) and accommodated within a flow channel (4) within the housing (1) extending between an inlet (19) and an outlet (20), a flow stripper (17) located between the inlet (19) and outlet (20) and through which the vanes (13) pass, a fluid flow loop (27) in the stripper (17) which intersects the path of rotation of the vanes (13), and control means (26) to control the flow of fluid through the loop (27) so as to vary the annular motion transferred to the fluid downstream of the stripper (17), thereby to selectively vary the output of the pump. The flow stripper (17) comprises a land portion (21) upstream of the loop (27) which restricts direct fluid flow through the stripper (17), and the control means (26) comprises valve means which controls a supply of fluid to the upstream end of the loop (27). The supply of fluid to the loop (27) is tapped from a high pressure region of the pump possibly via a second fluid flow loop (22) in the stripper (17).

Dependencies are inferred from the claim text.