Hale 4DK Series - Manual (Page 43)

Manual p/n: 029-0020-79-0 43
4DK Series Pumps
APPENDIX A GLOSSARY
Atmospheric ........ Pressure caused by the elevation of air above the earth. Air pressure is 14 pounds
Pressure
per square inch at sea level. Pressure increases below sea level and decreases
above sea level. The weather also effects air pressure. Atmospheric pressure
effects a pumps ability to pump from draft. Higher pressures increases a pumps
performance, while lower pressures can cause a noticeable decrease in lift.
Auxiliary............... Permits water from a pump to cool the radiator water through a heat exchange.
Cooling Valve
Capacity .............. Pump flow rating.
Cavitation ............ Occurs when the pump attempts to deliver more fluid than is being supplied. This
causes the formation of bubbles in the pump. When the bubbles collapse, the liquid,
under pressure, rushes in to fill the empty space. This damages the pump and must
be correct
ed immediately.
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 or impeller to create the pressure for fluid
Pump
movement.
Certification ......... Pumper test in accordance with NFPA standards to determine if a pump can deliver
its rated volume and pressure.
Check valve ........ A one-way valve or non-return valve that allows flow in one direction, but shifts to
prevent flow in the reverse direction.
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 ............ Prevents discharge fluid from returning to the eye of the impeller.
Rings
Compound........... A compound gauge is graduated to read pressure in "pounds per square inch" and
Gauge
"vacuum in inches of mercury."
Cut Water ............ Cut water is a wedge-shaped point between the volute (pump body) and the pump
discharge where the volume of fluid is directed to the victaulic discharge connection.
Dead Heading ..... Operating a pump without any discharge. The lack of flow causes temperatures to
rise inside the pump. See WARNING ! on next page (1-16).