Hale SMR - Manual (Page 32)

Introduction
2-18 Stainless Max Series Pumps
Positive................ A pump with a fixed flow delivered to the discharge with each revolution.
Displacement Pump
Positive................ Pressure above atmospheric.
Pressure
Power Valve ........ A valve that uses hydraulic pressure to transfer two-stage pump operation from
volume mode to pressure mode, and vice versa.
Pressure .............. Force per unit area.
Pressure .............. The pressure gauge is usually graduated in pounds per square inch (PSI) only. It
Gauge
is connected to the pump discharge manifold, thus indicating pump discharge
pressure.
Priming ................ Priming evacuates the air from the main pump and suction hose, thus creating a
vacuum. This allows atmospheric pressure on the source of the fluid to push the
fluid up into the suction hose and pump.
Priming Pump...... An auxiliary positive displacement pump which pumps air out of the booster pump
that creates a vacuum to prime the main pump. The priming pump is a rotary vane
type, electric motor driven. Once the main pump is primed and pumping, the
priming pump is shut off.
Priming Pump...... A valve located in the priming line between the priming pump and the main pump.
Valve
It remains closed at all times except when priming. The control is normally located
on the pump panel.
Pump Shift ........... A midship pump is usually mounted with a split gearbox installed in the drive shaft.
The pump shift moves a sliding gear in the gearbox that transmits power either to
the pump or the rear axle. In ROAD position, power is shifted to the rear axle for
driving; in PUMP position, the rear axle is disconnected, and power is shifted to the
pump shaft.
Relay ................... Movement of water from an apparatus at a water source to additional apparatus
until water reaches the fire ground.
Relief Valve ......... An automatic valve which, when activated by the relief valve control, will hold pump
pressure steady when discharge valves or shut-off nozzles are closed. The valve
maintains its given pressure by dumping the pump discharge flow into the pump
suction.
Relief Valve ......... A handwheel adjustment valve which controls and/or adjusts the relief valve to
Control (PM)
maintain the working pressure (i.e., set to control the desired pressure).
Series .................. Pressure position in which the first impeller’s discharge is fed to the eye of the
second impeller in a two-stage pump which then discharges the fluid from the
pump.
Service Test ........ Pump test performed to determine if the apparatus can deliver its rated volume and
pressure.