HALE DSD, Operating And Maintenance Manual, Page: 48 / 84

Glossary
G - 1
Atmospheric Pressure caused by the elevation of air above the earth.
Pressure
Auxiliary Permits water from a pump to cool the radiator water through a heat exchange.
Cooling Valve
Capacity Pump flow rating.
Cavitation Caused by the pump attempting to deliver more water than is being supplied. This causes the
formation of water vapor, and liquid water, under pressure, rushes in to fill the empty space.
This damages the pump.
Centrifugal Force that tends to make rotating bodies move away from the center of rotation.
Force
Centrifugal A pump that uses a rapidly spinning disk to create the pressure for water movement.
Pump
Certification Pumper test in accordance with NFPA standards to determine if a pump can deliver its rated
volume and pressure.
Check valve In two stage pumps, there are two swing check or flap valves in the suction passage of the
second stage. They are located in each side of the pump between the suction tube and the
pump body. These valves swing open when pumping in parallel for volume. They are
closed by first stage pressure when pumping in series for pressure.
Clearance Prevent discharge water from returning to the eye of the impeller.
Rings
Compound A compound gauge is graduated to read pressure in pounds per square inch and vacuum in
Gauge inches of mercury.
Double Water enters on both sides of the impeller.
Suction
Impeller
Dry prime Provides information on the ability of a pump to evacuate air and draft water.
Test
Eye, Impeller Point where water enters the impeller.
Flow Meter Measures the volume of water flowing.
Friction Loss of pressure in hose, fittings, standpipes, and other appliances because of the
Loss resistance between the water molecules and the inside surfaces of hoses, fittings,
standpipes, and other appliances.
Front-mount Pump mounted ahead of the engine.
Pump