Diaphragm pumps are driven by compressed air. The directional air distribution valve and pilot valve—the “air end”—are located in the center section of the pump. Liquid moves through two manifolds and outer chambers of the pump—the “wet end”. Generally, check valves are located at the top and bottom of each outer chamber or on a common manifold. The two outer chambers are connected by suction and discharge manifolds. Lincoln’s double diaphragm self-priming design offers many advances over other pumps.