A positive displacement pump is normally used for moving high viscosity fluids by continuously enclosing a fixed volume of liquid and mechanical movement of the pump. These pumps are chosen when accurate dosing or high-pressure output is desired in any application. The following are some types of displacement pumps for you to know.
There are broadly three types of positive displacement pumps. They are a Rotary pump, Reciprocating pump, and Linear pump. These are further classified as:
Rotary- gear pumps, screw pumps, rotary vane
Reciprocating- plunger pump, piston pump, diaphragm pump
Linear pump- rope pumps, chain pumps
In this type of pump, the liquid is supplied through a rotary and the pipe’s rotation takes the liquid to the releasing pipe. In a gear pump, the liquid is moved between two rotating gears. In screw pumps, there are two screw-type rotors and they turn against each other. When the screw is turned it sends the liquid from the inlet to the outlet. There is a cylindrical vane over the rotor in the rotary vane model. The vanes on the top catch the liquid once it starts turning, and it is sent to the outlet from there.
Reciprocating helps in the movement of liquid here. A plunger, piston, and a diaphragm form part of the pump. There is an inlet valve and an outlet valve where the inlet valve remains open and the outlet valve is closed. When the piston turns in the right direction, the liquid can be taken inside easily as the opening is big.
Here the movement of the liquid takes place in a linear motion. The piston withdrawal here is within the cavity and therefore operating noise will be much higher. A rope pump and a chain pump are types of this.