Metering pumps are devices that are used extensively in various types of industrial applications. They are positive-displacement, chemical-dosing devices which have the ability to vary their capacity, as conditions may require. Metering pumps have a high level of accuracy and are capable of pumping a wide range of chemicals such as acids, corrosives, and viscous liquids, etc. They transfer liquids in two stages, which are the intake stroke and the output stroke. These pumps are usually driven by a mechanized motor, although different types of drive mechanisms may be used depending upon the application at hand. These drive mechanisms can include fixed speed, variable speed, electric drive and solenoid drive.
During the intake process the liquid flows into the pump cavity and past the inlet check valve. When the liquid has passed the inlet valve, the inlet valve closes and the outlet valve opens up, allowing the liquid to flow out of the pump. You can adjust the flow rate in the pump by stroking speed, varying stroke length or effective stroke length. If you want to maximize the flow rate there are chemical metering pumps available that have three or more heads.
Metering pumps are used in the daily operations of many types of industries such as chemical processing and water treatment plants, food and pharmaceutical industries, petrochemical industries, metal working and chemical milling, and deep water environmental and testing analysis.
Metering pumps that are used in industrial applications will submerge a certain portion of the pump in an oil bath to assure reliability during continuous operation. Metering pumps are generally used in applications where the speed of the flow is low, but accuracy and systems pressure requirements are high. Also, when the fluid is corrosive or hazardous or it is being transferred at a high temperature, then metering pumps are required. They may also be used when flow proportioning is needed.
There are various factors to consider when choosing and sizing metering pumps such as the environment, the capacity, the type of liquid used, and construction materials of the pump. You need to know if the pump will be exposed to extreme temperatures and if it will be placed directly in the sunlight. The pump’s motor should be protected from sunlight as it can easily ignite if it is in a hazardous environment. You also need to know the pressure and flow rate that is needed and what type of liquids are going to be flowing through it. Metering pumps are made of various materials and come with plastic liquid ends and metal ends. You need to know what type is best suited to the liquid you will be using. Metal is considered to be better for use with acids.