How to select the chemical dosing pumps?

When determining which Dosing pump is the best option for a chemical-injection application there are a number of variables that must be taken into consideration, including:

• Flow Rate. Determining the exact flow rate that is required for the application is of paramount importance.
• Materials of Construction. Metering pumps are available in a variety of materials, most commonly 316 stainless steel, C-20 stainless steel, PVC and Kynar® PVDF. When selecting a metering pump’s materials of construction, the corrosion, erosion and solvent action of the chemical must be taken into consideration. The effects of erosion must also be considered when the chemical takes the form of an abrasive slurry.
• Chemical Makeup. Standard Dosing pumps are typically able to handle clear liquids with viscosities ranging from water-like to 1,500 cPs. Chemicals with viscosities that approach 5,000 cPs or have light suspensions will require special liquid ends. Those with viscosities up to 20,000 cPs or that contain up to 10% solids will require special diaphragms, while ones that automatically vent accumulated gas will need their own variety of liquid ends.
• Driver. Drivers, which can be powered by electricity, water, gas, air or the sun, must be selected according to the utilities that are available. Driver selection must also take into account any environmental hazards that may be found in the operating area, with the operator realizing that pumps used in remote locations may not be able to be inspected as often as those in controlled environments.
• Environment. Determine if the pump will be operating indoors or outdoors. If used outdoors, the pump must be sheltered from direct sunlight. Any pumps that will be used in freezing temperatures can only pump fluids that will not freeze at that temperature.
• Method of Control. The operator must know how the pump will be used, either manual continuous operation, on/off operation of operation that is governed by a process signal.