progressing cavity pump

progressing cavity pump

A Progressive Cavity Pump is a type of a progressive cavity pump which has a rotor rotating within a housing called a stator. The rotor is always metallic and the stator is made up of a rubber type of material. It looks somewhat like a screw thread – the fluid is between the cavities and the rotary motion of the rotor forces the fluid through from one end to the other.

Progressing Cavity Pumps are used when a product needs to be handled gently and are used in all sectors of industries to convey almost all types of media continuously, smoothly, with low pulsation and dosing in proportion to speed. They are used for dosing applications where accuracy is required (multi stage pumps) their range covers from the smallest dosing pumps with flow rates of a few ml to high-performance pumps that pump up to 1000 m³/h.

One of the main advantages of a progressive cavity pump is that it is easy to regulate the flow of product simply by regulating the speed of the pump.

progressive-cavity-pump-2
progressive cavity pump

Progressing Cavity Pump Description

Progressing Cavity Pump Benefits

  • Space-saving design and low maintenance costs
  • The stator is vulcanised into a metal tube and sealed off by a rubber layer at the two faces of the tube. A flow-in cone is formed at one end of the stator boring. 4 different stator rotor geometries available
  • Standard pin joints do not have hardened bushings, but they are sealed and filled with oil for optimum lubrication.
  • Standard shaft sealing is fitted with hard metal mechanical seals.
  • Compact design with directly flanged drive.

Progressing Cavity Pump Typical Design

Specific designs involve the rotor of the pump being made of a steel, coated with a smooth hard surface, normally chromium, with the body made of a molded elastomer inside a metal tube body. The elastomer core of the stator forms the required complex cavities. The rotor is held against the inside surface of the stator by angled link arms, bearings (immersed in the fluid) allowing it to roll around the inner surface (un-driven). Elastomer is used for the stator to simplify the creation of the complex internal shape, created by means of casting, which also improves the quality and longevity of the seals by progressively swelling due to absorption of water and/or other common constituents of pumped fluids. Elastomer/pumped fluid compatibility will thus need to be taken into account.

Two common designs of stator are the “equal-walled” and the “unequal-walled”. The latter, having greater elastomer wall thickness at the peaks allows larger-sized solids to pass through because of its increased ability to distort under pressure. The former have a constant elastomer wall thickness and therefore exceed in most other aspects such as pressure per stage, precision, heat transfer, wear, and weight. They are more expensive due to the complex shape of the outer tube.

Typical application areas

  • Food and drink pumping Oil pumping
  • Coal slurry pumping
  • Sewage and sludge pumping
  • Viscous chemical pumping
  • Stormflow screening
  • Downhole mud motors in oilfield directional drilling (it reverses the process, turning the hydraulic into mechanical power) Limited energy well water pumping