Abstract: Cleaning apparatus for cleaning a generally planar generally horizontal surface comprises at least one nozzle for providing a jet of cleaning liquid directed against the surface and which is mounted by an arm on a shaft for rotation about the axis of the shaft which is perpendicular to the surface. The nozzle rotates within a chamber defined by a casing assembly which has an open lower end closed by the surface to the cleaning and which carries a seal for sealing against the surface to contain cleaning liquid within the chamber. The casing assembly defines a peripheral liquid collection region from which the liquid is withdrawn through an outlet by a pump. The nozzle is self-motivating and may be associated with an impellor having blades for inducing flow of ambient fluid, e.g. air, into the chamber, the air flowing out of the chamber with the cleaning liquid and assisting removal of cleaning liquid therefrom.

Abstract: A diaphragm pump comprises a body defining a chamber in which a diaphragm is arranged to divide the chamber into a drive chamber and a pump chamber. The pump chamber has an inlet and an outlet for fluid to be pumped, each of the inlet and outlet being provided with a one-way valve. The drive chamber has an inlet for driving fluid and the inlet is provided with a valve which is open under normal operating conditions of the pump. The valve is arranged so that, if a high pressure persists in the pump chamber when the pressure in the drive chamber is relieved causing the diaphragm to expand, the diaphragm will contact the movable valve member of the valve to move it to a position closing the inlet opening so that the drive chamber is isolated from the drive fluid pressure variations while the abnormal pressure subsists in the pump chamber.