Abstract: A radial piston machine has a rotor which turns within the confines of a surrounding annular control face and is provided with substantially radial cylinder bores each accommodating a radially slidable piston having an outer end provided with a piston shoe formed with guide portions projecting circumferentially of the rotor beyond the associated piston and having contact faces which are in sliding engagement with the control face. Each of the contact faces has a hydrostatic bearing constituted by a depression surrounded by a sealing land, and recesses are formed in the respective contact faces outwardly spaced from the sealing lands, so as to separate the latter from outwardly adjacent portions of the contact faces.

Abstract: A sump containing a conventional sump pump has a battery operated emergency pump. A trapped air pressure operated switch turns the emergency pump on when the water level rises excessively in the sump and an alarm signal is given. If the trapped air operated switch fails to turn the pump on, a non-mechanical float switch does so after a further rise in the liquid level in the sump and at the same time an emergency warning signal is produced. The float switch also turns on the emergency pump if that pump had not previously been turned on due to a malfunction in the trapped air switch. When the emergency pump turns on, a battery charger is energized from the alternating current supply so as to prevent depletion of the battery so long as the alternating current is available. Normally, the battery charger is turned on periodically by a timer to maintain adequate battery charge on a regulated basis. If battery power fails alarm is actuated. An alarm is actuated when alternating current power failure occurs.

Abstract: A system for pumping of liquid under pressure, in which a pressure switch is adapted to control the starting and stopping of the pump within a safe pressure range, and in the event of malfunction of the pressure switch, the service line and associated plumbing is isolated from the pump to protect against development of pressures in the serviceline which might damage the plumbing.