Oberdorfer Bronze Gear pumps
Pump housings and gears are made of top quality bronze, shafts are
from stainless steel 303. Bearings are designed of high performance
carbon-graphite material selected for wear resistance and long
Gear pumps are positive displacement pumps. Each shaft
revolution displaces a definite amount of l9iquid relatively
unaffected by the back pressure 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
lubricants. Maximum shaft speed is 1750 rpm.
A relief valve is necessary in the system if the discharge line
contains any throttling devices, such as a shut-off valve, a spray
nozzle or other restrictive device. This will return the liquid to
the suction side or to the tank. The relief valve is also available
as part of the pump itself (R-model pumps). However, built-in
relief valves are only good for intermittent service. A built-in
relief valve is strictly a safety device against overpressure. It
will not work successfully as a pressure or flow control device.
For this purpose a separate relief valve in the pressure line must
Service life will be increase substantially if the liquid pumped
is clean and has a lubricity value. These pumps have extremely
close tolerances. Fine abrasives like sand, silt, or powder in
suspension will destroy pumping ability.
Liquids compatible with bronze, stainless steel and the acrylic
graphite packing can be pumped. Solvent resistant packings and
Teflon® packings are also available.
Temperature extremes are detrimental to service life and should
be avoided. Basic metals of construction allow temperature range of
_40F to 400F. The acrylic graphite packing is rated to 500F.
Freezing liquid in the pump can deform or damage the pump.
Viscous liquids such as molasses or oils require a lower pumping
speed, in extreme cases as low ass 200 R.P.M. Liquids with specific
gravities heavier than water such as dry cleaning fluids require an
increase in motor horsepower directly proportional to the increase
in specific gravity over water.
A rotary gear pump is capable of lifting water on the suction
side as high as 20 feet. Though gear pumps are self-priming, a foot
valve is recommended. For pumping water directly from streams or
ponds, a wire mesh strainer must be used at the beginning of the
suction line to prevent stones from entering the pump. Strainer and
foot valve are commercially available as combination units.
NOTE: For the individual pump performance curves and dimensional
drawings, please select a model from below. Used for vegetable oil,