Hydraulically driven bellows pump

Abstract

A hydraulically driven diaphragm pumping machine ('pump'), in particular for water and difficult-to-pump materials, comprises at least two side-by-side pumping units. Each pumping unit comprises a hydraulically-driven pump cylinder () and a separate non-pump hydraulic drive cylinder (). The pump cylinder () has a lower first end with a first inlet and outlet for fluid to be pumped and an upper second end with a second inlet and outlet for hydraulic fluid. The pump cylinder () contains a bellows () closed at its lower end and open at its upper end for communication with hydraulic fluid. The outside of the bellows () defines a space for fluid to be pumped. The bellows () of the pump cylinder () is arranged to be driven by hydraulic fluid supplied at its top end, in concertina like expansion and contraction to pump the fluid to be pumped adjacent the lower first end of the pump cylinder (). The hydraulic drive cylinder () is placed side-by-side the pump cylinder (). The hydraulic drive cylinder () has a lower first end associated with a hydraulic drive an upper second end containing hydraulic fluid communicating with the upper second end of the pump cylinder (). The hydraulic drive terminates at its upper end with a drive piston () slidably mounted in the hydraulic drive cylinder (). The hydraulic drives of the hydraulic drive cylinders () of the two pumping units are connected by a hydro-mechanical connection () designed to control drive of the hydraulic fluid to advance and retract the pistons () of each hydraulic drive cylinder ().