12 Oct Metering Pumps and It’s Uses
Where and Why Metering Pumps are Used
Metering pumps are specifically designed for the movement of specific volumes of fluid within a particular time frame. With the technology, it is possible to get an exact flow rate, which can be adjusted. The process is often referred to as metering, explaining the name for these types of pumps. Thus, wherever precision pumping is needed in terms of the volume of liquid in a specific period, a metering pump is the best technology for the task.
However, the name does not refer to specific types of pumps, but rather the function of metering. Although these units are suitable for pumping potable water, the units are more widely used for pumping liquids, such as chemicals.
The units are designed for ensuring the right flow rate of the liquids for a specific period as needed for the particular application. Each of these has a rating for the maximum pressure it can handle for discharging. It is, therefore, important to use the applicable unit according to its temperature and pressure ratings for the particular application and liquid type that must be discharged.
Also referred to as proportioning or dosing pumps, the metering devices provide for excellent accuracy in flow-rate management. Applications range from ensuring a variable flow within the specified parameters for the application to injection of a dose of chemicals. The units can also be used for maintaining a specific flow rate irrespective of the viscosity of the fluid.
Industries where the metering of pumped fluids is especially important include, but are not limited to:
- Food processing plants
- Chemical processing units
- Water treatment plants
- Wastewater treatment systems
- Petrochemical industries
Everything from disinfectants, fragrances, and pigments to acids can be metered to ensure correct volumes are pumped in the specific time frame.
Pumps suitable for metering range from centrifugal to positive displacement pumps. The type to be used is determined by factors, such as accuracy required in metering, ability to control the flow, the pressure against which the liquid must be displaced, and the volume to be pumped.
In general, reciprocating units that use diaphragms, pistons, or plungers are used for metering applications. The reason is that these units can ensure consistency in flow rate over a wide pressure range. That said, technological advances over the years have made it possible to control flow rate when using gear or peristaltic types as well.
The piston-based types use suction and compression strokes for the pumping of fluid. The liquid is drawn in through the suction stroke and discharged with the compression stroke.
With plunger-based metering pumps, the same technology is used, but the liquid transfer rate depends on the size of the plunger. Both the plunger and piston types facilitate the delivery of an exact amount of liquid.
With the use of metering pumps, chemicals, such as bleaching agents can be applied to kill bacteria. Precision application is necessary in such applications. The units are often used to adjust pH in liquids. This may be necessary in a process plant where the water pH must stay at 7. In addition, such units can be used for dosing corrosion inhibitors for the prevention of fouling that can lead to plant infrastructure failure if not managed. Metering pumps are also often used for the dosing of flocculants into mix tanks.
The technology thus provides a means for accurate dosing of chemicals and ensuring consistency in flow. With consideration of their important functions, reliable operation is essential. To this end, such pumps must be able to provide superb accuracy and must be corrosion resistant. The units must be able to operate in a wide range of temperatures and must be durable and able to operate at an ongoing basis.
Because safety is so important in the applications, it goes without saying that the units must be built to ensure a low risk of failure. The fewer potential fail points a unit has, the better. This is especially true when extremely hazardous chemicals must be applied.
The short introduction to metering pumps highlights the range of applications, types of pumps that can be used, and the importance of reliability. We provide a wide range of chemical material handling technologies that are reliable, accurate, low on maintenance, and durable. View our product range and get in touch for help in choosing the units most appropriate for your particular industry and applications.