Abstract: An inner cylinder and a substantially larger outer cylinder are joined as two verticle concentric cylinders. Verticle partitions between the cylinders divide the space between the cylinders into an inlet chamber and an outlet chamber which is substantially larger in volume than the inner chamber. The inner cylinder has a central pumping section positioned between upper and lower valve sections. In the valve section ports extend through the inner cylinder wall to the inlet and outlet chambers. Spring loaded valves close the ports. Tension springs extend across the inlet chamber and compression springs extend across the inner cylinder to close the inlet valves. Tension springs extend across the inner cylinder the close the outlet valves. The elastomeric valve flaps have rigid curved backing members. A piston rod extends through one end cover to move a piston in the central section. An inlet is connected to the inlet chamber and an outlet is connected to the outlet chamber.

Abstract: A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

Abstract: Two concentric vertical cylinders are separated by three radial partitions. An opening at the bottom of one of the partitions connects an air cell on one side of the partition with an outlet chamber on the other side of the partition. The two other partitions form sides of an inlet chamber, which receives fluid from outside the outer cylinder. The inner cylinder has a central pumping section positioned between upper and lower valve sections. In the valve sections ports extend through the inner cylinder wall to the inlet and outlet chambers. Spring loaded valves close the ports. Tension springs extend across the inlet chamber or compression springs extend across the inner cylinder to close the inlet valves. Tension springs extend across the inner cylinder to close the outlet valves. The elastomeric valve flaps have rigid curved backing members. A piston rod extends through one end cover to move a piston in the central section.

Abstract: A windmill control system having lever means, for varying length of stroke of the pump piston, and a control means, responsive to the velocity of the wind to operate the lever means to vary the length of stroke and hence the effective displacement of the pump in accordance with available wind energy, with the control means having a sensing member separate from the windmill disposed in the wind and displaceable thereby in accordance with wind velocity.