Hale DSD - Manual (Page 18)

CAVITATION
Often referred to as “running away from the water supply.” Cavitation simply means that the
operator is trying to pump more water out of the pump than is going into the pump.
AUXILIARY COOLING
Model K Auxiliary Heat Exchanger/Cooler
NFPA 1901 requires a supplementary heat exchanger cooling system for the pump drive
engine during pumping operations. Hale model “K” heat exchangers meet the NFPA 1901
requirements. The units can be used with any size radiator and use water from the pump to
help maintain the proper a temperature of the engine coolant. The cast-iron housing and
copper tubing coil keep the water and coolant from contaminating each other. A valve is
supplied on the operator’s panel to allow the operator to control the amount of water being
supplied to the Model “K” heat exchanger This valve is needed to keep the apparatus from
operating at a temperature below the recommended level
Pump Overheating Protection
An optional Thermal Relief Valve (TRV) can be attached to the main pump body. This valve
prevents the Overheating of the pump under certain operating conditions The valve monitors
and controls the temperature of the water in the pump. When the temperature exceeds 120°F,
the valve automatically opens and discharges a small amount of water either to the ground or
into the water tank, allowing cooler water to enter the pump. After the temperature reduces to a
safe level, the valve closes until the temperature is exceeded again.
DISCHARGE, SUCTION, DRAIN, AND INLINE VALVES
Discharge and suction valves regulate the amount of water entering and leaving a pump. Each
valve includes a locking device that permits operation in any position from fully opened to fully
closed. Several types of valves are available for Hale midship pumps.
The suction and discharge valves are quarter-turn ball-type with a locking handle. As the valve
handle is moved, the ball can rotate from being in-line with the waterway to a position 90
degrees to the waterway, or any position in between, thus reducing or stopping the flow of
water. Inline valves are also quarter-turn ball-type valves. These valves can be used in either
suction or discharge lines
The optional Hale tank-to-pump valve is a flanged, three-inch, full flow ball device that includes
a three-inch NPT and four-inch flexible coupling inlet connection An optional built-in Hale
bronze check valve is specifically designed for the purpose of avoiding accidental overpressure
of the booster tank and is strongly recommended.
At least one full flow suction valve with locking handle can be provided on the pump. The body
of each suction valve connects into the pump suction with a maximum of one long sweep 90°
elbow between the valve and the pump suction.
The Hale drain valve is a sliding plug type valve used to relieve pressure from hose lines after
pumping. To open, pull the knob out; to close, push the knob in. The valve must be seated
completely to prevent leakage while priming and pumping.
Each suction and discharge valve on a Hale pump may be equipped with a drain. Opening the
drain before uncoupling the hose relieves the pressure in the line. Also, water must be drained
from the pump during freezing conditions through the master drain valve.