Oberdorfer Gear Pump Model# N991-32S5
Pump housings and gears are made of top quality bronze, shafts are
303 stainless steel. Bearings are designed 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.
Recommended pressure limits are 100 PSI for water and non-lubricants,
150 PSI for oil and other lubricants. The maximum shaft speed is 1750
RPM. Close-coupled gear pumps are normally supplied with a Nitrile lip
seal. A lip seal made of fluoroelastomer is available as an option. For a fluoroelastomer Seal, add S5 to the pump model number.
FEATURES
- Rugged corrosion resistant bronze construction
- Compact close-coupled design
- Stainless steel shafts
- Durable bronze spur gears
- Process lubricated carbon graphite bearings
- O-ring cover seal for maximum leak protection
- Nitrile Lip Seal -standard
- Easy field assembly to a variety of motor frames
- For typical DC motor pump units - see N991-32 DC
- For compact AC motor pump units - see Close Coupled Bronze Adapterless Rotary Gear Pumps
- For bronze pedestal pumps and mechanical seal styles - see model N1000
DRIVE
Close-coupled pumps are mounted directly to the
electric motor by means of a suitable adapter bracket. The pump drive
shaft is connected to the motor shaft by a flexible coupling.
LIQUIDS & TEMPERATURES
These pumps are suitable for all liquids that are
compatible with bronze. Most common liquids are water, oil, and mild
chemicals in the pH range of 4 to 11. Viscous liquids require reduced
shaft speeds of 1150 RPM or lower. (Consult factory.) Liquids containing
solids, abrasives, powders, or paint pigments are definitely not
recommended for gear pumps. If abrasives are unavoidable, use a very low
shaft speed. The recommended liquid temperature range is from 32o F to
140o F for best pump life. If more extreme temperature conditions exist,
factory should be consulted. Freezing of water-filled pumps can cause
damage and must be avoided. Oils at low temperatures are very viscous
requiring a lower speed or extra power.
SUCTION LIFT
As a general rule, the suction lift should be
kept at an absolute minimum by placing the pump as close to the liquid
source as possible. A gear pump in new condition can lift 20 feet of
water in the suction line. A foot valve (preferably with built-in
strainer) is recommended at the beginning of the suction line. For a
first start-up, the pump should be primed to avoid dry running. Minimum
size of the suction pipe is the size of the pump inlet port. For longer
suction lines (over 3 feet) or for viscous liquids, the pipe should be
at least one size or two sizes larger than the pump inlet port.
