UL Field Inspections. Yesterday we were greeted at the front door by our UL Inspector for an unannounced field inspectionâ¦surprise! At another facility there might be a cry for alarm, but at Coast Label Company there was no mad scramble, no rush to hide this, or go find that. We just sat him down and asked what he was checking today.
Jet pumps create suction in a rather novel way. The pump is powered by an electric motor that drives an impeller, or centrifugal pump. The impeller moves water, called drive water, from the well through a narrow orifice, or jet, mounted in the housing in front of the impeller.
To see how the pump works, look at the drawing below. The pump consists of a small diameter pipe (called the piston) inserted into a larger diameter pipe (called the cylinder). The drawing shows the pump at two points during its operation. The top drawing shows air being drawn into the pipe by pulling out the piston. The bottom drawing shows air exiting the pipe when the piston is pushed back in. At the right end of the pipe is a commercially bought one-way valve.