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.
First, its mechanical action creates a vacuum at the pump inlet which allows atmospheric pressure to force liquid from the reservoir into the inlet line to the pump. Second, its mechanical action delivers this liquid to the pump outlet and forces it into the hydraulic system. A pump produces liquid movement or flow: it does not generate pressure. It produces the flow necessary for the development of pressure which is a function of resistance to fluid flow in the system.