Positive displacement pumps are “constant flow” pumps.
Despite pressure in the discharge, positive displacement pumps will not adjust their flow rate. To prevent pressures exceeding that of safe levels within the system, relief valves must be installed. In the event of a blockage in the discharge piping, the pressure can safely be relieved before damage occurs. Without a relief valve, the pump will continue to increase the pressure until the pressure is “relieved”- either by a piping failure, cracked fluid end, or a broken coupler or driveshaft. These failures are often catastrophic, endangering personnel and surrounding equipment systems.
What Are Positive Displacement Pumps Used For?
- High Pressure, Low Flow
- High Viscosity
- Mud or Abrasives
- Precise Flow
Types of Positive Displacement Pumps
Reciprocating Pump
- Plunger Pump
- Piston Pump
- Diaphragm Pump
Rotary Pump
- Progressive Cavity
- Screw Pump
- Gear Pump
- Lobe Pump
- Peristaltic Pump
- Swash Plate
- Rotary Vane
