Bronze gear pump. 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
service life. Motor may not include handle.
Gear pumps are positive displacement pumps. Each shaft
revolution displaces a definite amount of liquid 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. If used
continuously, the pump will over heat. A built-in relief valve is
strictly a safety device against over pressure. It will not work
successfully as a pressure or flow control device. For this purpose
a separate relief valve in the pressure line must be used.
Service life will be increase substantially if the liquid pumped
is clean and has a lubricity value. These pumps have extremely