A metering pump is a pump used to pump
liquids at adjustable flow rates which are precise when
averaged over time. Delivery of fluids in precise adjustable
flow rates is sometimes called metering. The term "metering
pump" is based on the application or use rather than the
exact kind of pump used, although a couple types of pumps
are far more suitable than most other types of pumps.
Although metering pumps can pump water,
they are often used to pump chemicals, solutions, or other
liquids. Many metering pumps are rated to be able to pump
into a high discharge pressure. They are typically made to
meter at flow rates which are practically constant (when
averaged over time) within a wide range of discharge
(outlet) pressure. Manufacturers provide each of their
models of metering pumps with a maximum discharge pressure
rating against which each model is guaranteed to be able to
pump against. An engineer, designer, or user should ensure
that the pressure and temperature ratings and wetted pump
materials are compatible for the application and the type of
liquid being pumped.
Most metering pumps have a pump head and
a motor. The liquid being pumped goes through the pump head,
entering through an inlet line and leaving through an outlet
line. The motor is commonly an electric motor which drives
the pump head.
