A positive displacement pump is a type of pump that works by trapping a fixed amount of fluid and then forcing it through the pump’s outlet. Positive displacement pumps operate by creating a flow of fluid by capturing and then releasing a fixed volume of fluid, rather than by imparting energy to the fluid as with a centrifugal pump.
There are several types of positive displacement pumps, including reciprocating pumps, rotary pumps, and diaphragm pumps. Reciprocating pumps use a piston or plunger to move fluid through a cylinder, while rotary pumps use gears or lobes to move fluid through a chamber. Diaphragm pumps use a flexible diaphragm to create a pumping action.
Positive displacement pumps are commonly used in applications where a precise and constant flow rate is required, such as in chemical dosing or in the transfer of viscous or abrasive fluids. They are also used in high-pressure applications, such as in oil and gas drilling or in hydraulic systems.
One of the key advantages of positive displacement pumps is that they are self-priming, which means that they can pump fluids without the need for external priming. They are also able to handle high-viscosity fluids, and are generally more efficient than centrifugal pumps at low flow rates. However, they can be more expensive and require more maintenance than centrifugal pumps