Abstract

A novel system is described for withdrawing liquids from a subsurface horizon utilizing a tubular diaphragm pump. A specific and unique pump is disclosed comprised of an elongated body member which includes a main chamber member extending longitudinally of the body member. In a preferred embodiment, a delivery tube is concentrically mounted within the chamber and forms an annulus with its outer surface and the inner walls of the chamber. The tube is provided with spaced perforations along its length within the chamber. Upper and lower check valves are in fluid communication with and at opposite ends of the delivery tube. Flexible tubing or a bladder is placed in the annulus and is normally spaced from the delivery tube. Means apply hydraulic pressure to the outer surface of the bladder to move the bladder toward the delivery tube to expel liquids out of the chamber through the upper check valve and also for releasing the hydraulic pressure to move the bladder away from the delivery tube to aspirate liquids into the chamber by way of the delivery tube through the lower check valve.