Abstract: A reciprocating piston motor has the piston biased in return stroke direction and driven in power stroke by air pressure introduced between the head of the piston and a closure across the end of the working chamber cylinder. A valve which closes an exhaust port leading from the working chamber, is opened at the end of the power stroke by working chamber air pressure and the air pressure is evacuated from the working chamber. The valve is returned to closing relation to the port by the returning piston, thereby resetting the motor for another cycle of operation.

Abstract: A high pressure piston pump especially suitable for moving heavy high viscosity and abrasive materials, which has its piston in substantial clearance relation in a cylinder, is operable in a pumping stroke to drive into a flexibly deflectable, elastic combination valving, wiping and sealing elastomeric ring which not only maintains tensioned sealing engagement with the piston but also reacts to pump pressure to improve the sealing engagement during pumping stroke of the piston, and permits relaxation of grip on the piston and leakage forwardly along the piston during return stroke suction in front of the piston.