Both positive displacement and rotodynamic pumps are used for food and beverage processing. A few positive displacement pumps that are used are:
Controlled volume metering pumps—or simply metering pumps—pump fluid through reciprocating action. They are often used to pump a fixed amount of a mixture in situations where precision is crucial. These metering pumps have a stroke length adjustment so that the volume delivered can be precisely metered, which is important in many blending or mixing operations. In food processing, this may include the addition of dyes or other ingredients into the product.
Flexible vane pumps are a type of rotary positive displacement pumps that have a broad range of uses, including food and beverage processing and chemical processing. The pump uses an elastomer rotating member with enlarged vane tips that form a pumping chamber in conjunction with a casing when the rotor is placed with the shaft centered in the substantially circular casing that incorporates an eccentric section. Discharge forcing action is accomplished as the vane bends in the eccentric section, effectively squeezing liquid from the discharge chamber.
Peristaltic pumps use a flexible tube compressed between one or more moving rollers or shoes and a fixed track. The
roller or shoe compresses the tubing and pushes the fluid in front of the roller or shoe toward the discharge end of the tubing. For the food and beverage industry, a primary benefit is that the fluid contacts only the tubing. This is a benefit for food and beverage applications, as reactivity with the pump piping does not need to be addressed.