HALE DSD, Operating And Maintenance Manual, Page: 10 / 84

DESCRIPTION OF HALE MIDSHIP PUMPS
SINGLE-STAGE
There are two series of single-stage pumps:
• 750 GPM to 1250 GPM
• 1000 GPM to 2000 GPM
Hale single-stage pumps are of a size and design to attach to the chassis rails of commercial
and custom chassis. The pump is driven from the truck main drive line. Generally, it consists of
the following major components:
• Pump Body
• Impeller and Shaft Components
• Gearbox
• Priming System
• Pressure Control Device
• Valves
The number of impellers on a common shaft determines the number of pump stages. The Hale
series of single stage pumps provides the same normal operating and rating test pressures as
the Hale series of two-stage pumps. The two-stage pump provides an additional level of
operating pressures if required, but adds some operating complexity.
Single-Stage Pump Operation
Hale single-stage pumps use a single impeller with a double suction entry to develop the
required volume and pressure. Dual cutwaters strip water from the rotating impeller and direct
it to the discharge path. Figure 1-9 shows the flow of water through a Hale single-stage pump.
Water enters the two suction channels and both sides of the impeller, thereby maintaining axial
balance. The double suction impeller develops discharge pressure and directs the water to the
dual cutwaters and then to the discharge valves. The impellers are radially and axially
balanced. Radial hydraulic balance is maintained by the opposed discharge volute cutwaters
The cutwaters are wedge shaped and divide the water between the volute and the pump
discharge.
DUAL CUTWATERS
CROSS SECTION
Figure 1.9. Water Flow Through a Hale Single Stage Pump
END VIEW