Metering pumps, also referred to as "dispensing," liquid," "chemical feed," "proportioning" and "fluid metering pumps," are positive displacement pumps that move exact amounts of liquid in any given time frame, resulting in accurate flow rates. These pumps move a consistent volume of liquid with each cycle or revolution. The distinguishing characteristic of these pumps is their accuracy. Metering pumps have an average accuracy rate of plus or minus one percent. Another feature of metering pumps is their ability to vary the flow rate. This is either manual or automatic, depending on the system and process requirements.
The majority of metering pumps are equipped with a micrometer screw adjustment, but a pneumatic or electronic actuator can also be used if the pump flow rate requires alteration due to a process signal. These pumps move fluid in two stages. First is the intake stroke in which liquid is carried into the pump cavity beyond the inlet check valve. In the next stage, after the inlet valve closes, the outlet valve opens and the fluid is forced out. Altering the stroke length or stroking speed adjusts the flow rate of the metering pump.
The majority of metering pumps are equipped with a micrometer screw adjustment, but a pneumatic or electronic actuator can also be used if the pump flow rate requires alteration due to a process signal. These pumps move fluid in two stages. First is the intake stroke in which liquid is carried into the pump cavity beyond the inlet check valve. In the next stage, after the inlet valve closes, the outlet valve opens and the fluid is forced out. Altering the stroke length or stroking speed adjusts the flow rate of the metering pump.
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Last Updated: June 16, 2007
Last Updated: June 16, 2007
What are Metering Pumps?
Metering pumps can be dispensing devices of chemicals and other fluids. Typically, these pumps are used to meet any or all of the following requirements: high accuracy dispensing, high system pressure, low flow rates in GPH or mL/hr, the ability to move hazardous or corrosive fluids or controlled dispensing via a microprocessor, computer or PLC. Water treatment systems, chemical processing and laboratory applications use metering pumps. Plastic extrusion machines use metering pumps to maintain a constant flow of melted plastic through the die. These pumps are also great for spray paint applications, as they enable quick changeover of colors. Additionally, manufacturers of processed food use metering pumps to ensure a constant rate of food additives during their processes.
Different factors determine which metering pump is appropriate for a specific application. Since each fluid that needs to be pumped is unique, it is important to select a pump based on the specific characteristics of the fluid, such as whether or not it is abrasive or corrosive. Some other important factors include fluid viscosity, temperature, flow and pressure rates. Since metering refers to the accurate delivery of a measured amount of liquid, metering pumps are useful in numerous applications throughout the world.
Different factors determine which metering pump is appropriate for a specific application. Since each fluid that needs to be pumped is unique, it is important to select a pump based on the specific characteristics of the fluid, such as whether or not it is abrasive or corrosive. Some other important factors include fluid viscosity, temperature, flow and pressure rates. Since metering refers to the accurate delivery of a measured amount of liquid, metering pumps are useful in numerous applications throughout the world.
