Abstract: A fluid operated pumping system which includes a main power cylinder divided into a power chamber and a pump chamber by a reciprocally mounted power piston. An actuator piston is connected to the power piston for synchronous movement therewith and is reciprocably mounted in an actuator cylinder. A diaphragm type four-way transfer valve is interposed between a power fluid source and the main power cylinder and actuator cylinder, to both of which the valve is connected, and functions to alternately and cyclically charge power fluid at a relatively high pressure to the power cylinder and actuator cylinder, and to concurrently discharge power fluid at a relatively low pressure. The system further includes a needle valve controlled, diaphragm-type, astable pneumatic amplifier which is connected to, and controls the movement of, the transfer valve.

Abstract: A filter for arresting the flow of a liquid entrained, deformable solid or semi-solid body through a tubular vessel or conduit, the filter including a plurality of convergent legs in generally conical array and joined at their convergent ends to an apical hub, each leg having a reversely bent hook at its end which is distal with respect to the hub. Each leg also includes a plurality of bends intermediate its length, which bends decrease the solids by-pass capability of the filter without concurrent fluid occlusion.An intrument for inserting the filter in a tubular environment is provided and includes a carrier for supporting the filter in a collapsed, compact status, an ejector mounted in the carrier for ejecting or releasing the filter from the carrier and an elongated flexible tube connected to the carrier for moving the carrier and filter to the locus of use of the filter, and for supplying an ejector actuating fluid to the ejector.