Pump housings and gears are made of top quality bronze, shafts are
303 stainless steel. Bearings are made of high performance
carbon-graphite material selected for wear resistance and long service
life. Gear pumps are positive displacement pumps. Each shaft revolution
displaces a definite amount of liquid relatively unaffected by the
backpressure in the discharge line. Shaft speed and flow are directly
proportional.
DRIVE
Pumps should be mounted on a rigid base and
properly aligned with the motor. Direct drive via flexible shaft
coupling is the preferred method. When a belt drive is needed,
additional support is necessary to absorb the added pulley load. this
can be accomplished in two ways:
- Use the standard pump arrangement by adding an independently supported jackshaft (see figure 2 below) or use kit 2P
- When space is an issue, use an optional “long shafted” pump and add a properly shimmed pillow block bearing (see figure 1).
LIQUIDS & TEMPERATURES
Service life will be increased substantially if
the liquid pumped is clean and has some degree of lubricity. These
positive displacement pumps have tight tolerances. Fine abrasives like
sand, silt, or powders in suspension will accelerate pump wear and
reduce throughput. Liquids compatible with bronze and stainless steel
can be pumped providing proper seal has been specified (see chemical
compatibility or check factory). When possible, flush the pump after
each usage. Temperature extremes are detrimental to service life and
should be avoided. Basic metals of construction allow a temperature
range of -40 to 400oF. Some lip and mechanical seal elastomers have a
limit of 212oF. (see engineering data or check factory). Allowing a
liquid to freeze in the pump can cause damage.
Service life will decrease for fluids without lubricity (e.q. water,
solvents). Close tolerances and the positive pumping action make the
rotary gear pump capable of lifting water on the suction side as high as
20 feet.
Though gear pumps are self priming, a foot valve is recommended. If
possible, wet the gears with liquid to be pumped for the first dry
start. Liquid retained in the system and gear chambers serves to “wet”
the pump on subsequent starts.
*For pressures over 100 psi, the above selections are suitable for pumping fluids with lubricity (e.q. oils, polymers).
SUCTION LIFT
Close tolerances and the positive
pumping action make the rotary gear pump capable of lifting water on the
suction side as high as 20 feet. Though gear pumps are self priming, a
foot valve is recommended. If possible, wet the gears with liquid to be
pumped for the first dry start. Liquid retained in the system and gear
chambers serves to “wet” the pump on subsequent starts.
