Abstract: A high pressure pump in which at least one reciprocatingly driven piston acts on a hydraulic fluid communicating with one side of a diaphragm, the other side of the diaphragm communicating with a fluid to be displaced by the pump. The diaphragm is made of elastomeric material, and is relatively thick so that it is substantially self-restoring on the return stroke of the piston even in the event of total blockage of the supply of fluid to be displaced.

Abstract: A surface cleaning device comprising nozzle means for directing a high-pressure jet of liquid at an acute angle on to a surface, and collection means for collecting the liquid after deflection from the surface, said collection means including an inlet duct of approximately constant cross-sectional area having a lower wall terminating with an edge adapted in use to contact the surface ahead of the area of impingement of the jet, whereby in use the liquid jet deflected from the surface co-operates with the duct to create a jet-pump which sucks entrained air, stray liquid, and debris cleaned from the surface, into the duct.