Oberdorfer N991 Gear Pump Peo 1/4" Brz Buna
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.
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