In which applications are metering pumps used?
Metering pumps (also known as controlled volume pumps, chemical injection/feed pumps, or dosing pumps) are typically used for the injection of chemical additives, proportional blending of multiple components or metered transfer of a single liquid. These types of pumps are used in applications requiring highly accurate, repeatable and adjustable rates of flow.
Like the vast majority of pump types, ultimate performance is determined by not only correctly specifying the type and size of the pump but also by the design of the suction and discharge piping. This is particularly important for metering pumps because they have a characteristic pulsating output due to their reciprocating action. The rate of flow of a controlled-volume pump is a function of the cross-sectional area of the plunger or piston or displacement of the diaphragm, the stroke length and the strokes per minute. The rate of flow is adjusted by changing the stroke length and/or the stroking speed.
Metering pumps are characterized by their ability to meet specific performance requirements concerning steady state accuracy, turn down ratio, repeatability and linearity.
For more information on metering pumps and their piping design refer to ANSI/HI 7.8 “Controlled Volume Metering Pump Piping Guideline” at pumps.org.