Positive Displacement Pumps
Positive displacement pumps do not use impellers to move the fluid. Instead, they utilize rotating or reciprocating parts to push and transport the liquid into an enclosed volume. This design creates pressure, which drives the liquid to its destination. A positive displacement pump is ideal for higher viscosity liquids that are transported at low flow rates but a higher pressure.
- PD pumps are sometimes called constant-volume pumps because they maintain a constant speed and flow. Even if the system pressure varies, the flow remains constant.
- PD pumps can handle a variety of fluid types: high, low and variable viscosity; shear sensitive fluids; solids; and liquids with a high percentage of air or gas entrainment.
- Their capacity is not affected by the operation pressure.
- They are excellent for applications with flows below 100-gpm and above 100-psi.
- They can be 10 to 40 points more efficient than centrifugal pumps when handling viscous fluids.
Custom Pump Curve
A pump curve is a graphical representation of a pumps flowrate against a certain level of head. Using a pump curve that is accurate for your application will greatly help in selecting the correct pump, ultimately saving you time and money.
Pump curves are developed from data gathered during testing of the pumps performance at the manufacturer’s facility and provides the end-user with a graph of how the pump will operate over a set range. To build the pump curve, our engineers compile several variables including type of material, fluid viscosity, distance to pump, target GPM, and factors that are job-specific. This ensures the most efficient pump is recommended for your project.
Positive Displacement Pump Advantages
- Are able to self-prime
- Can be designed as a sealless pump
- Constant speed & flow
- Efficient at handling viscous liquid
- Capacity not affected by operation pressure