US Patent 7845399 Downhole well pump

An apparatus for use with production tubing to pump fluid from a well to the surface includes a tubular conduit having upper and lower portions. The lower portion has an inner or outer diameter greater than the diameter of the upper portion to form a first internal or external shoulder where the lower and upper portions are engaged. Seals are disposed on the conduit for sealing between the conduit and a well casing. One or more valve sections have a valve adapted to open during downwards motion through fluid and to close during upwards motion through fluid.