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Screw Pumps


Screw Pump Overview

Screw pumps are a part of the dry gas pump family and are positive displacement pumps. These pumps use two screw-shaped rotors that intermesh to move the gas along the pump. These screw pumps are most popular with industrial gas pumping tasks, including root blowers or roughing pumps that do not need oil. The screws in the pump interlock with one another, generating pressure to move the fluids along the pump axis. The liquid goes into these pumps through the inlets and the interlocking screws. The rotary screw pumps are most popular in the power generation industry as they allow controlled, consistent liquid flow. For instance, one can use these screw pumps for jacking oil, fuel injection, bearing lubrication, and water applications for hydroelectric projects. The screw pumps are ideal for industrial applications because they require minimal maintenance and are easy to use.

Screw Pump Brands

Ideal Gusher Applications:
  • HVAC
  • Industrial heat transfer
  • Waste
  • Sump
  • Mixing
  • Machine cooling

Screw Pump Design

The screw pumps have simple construction that consists of three spindles, where two of these screws act as driven screws. The other spindle is the driver and controls the movement of the mechanism. The screws have sufficient spaces between them, allowing water to pass through the pump casing from the inlet to the deposit point. The electrical motor moves the liquid from the fluid to the screws, as most of these pumps have housing suction with discharge on the sides.

Screw Pump Working

The screw pump is a positive displacement pump, meaning the screw moves in and out of a socket, and the liquid flows between the spaces available. The screw pump displaces the area, allowing the fluid to move from one point to another using two counter-rotating screws. The two rotating screws move towards each other and create pump pressure. The screwdriver gets power when the screw pump turns on through an electrical motor. The driver screw starts operating, making the driver screws move along it.

 This movement creates a minimal vacuum in the inlet section, causing the fluid to suck from the inlet section through the pump casing towards the discharge port. The fluid enters from the inlet and collects between the gaps of the moving screws. The driven screws move the water reducing the total trapped water between the screws. The pressure in the liquid increases gradually until the screw pump starts transferring the fluid where needed. Users need to lubricate the screws while pumping oil or other viscous material to reduce the space between the screws. However, the screws and other components do not make contact in the case of other lighter liquids like water.

The parts can wear out without proper connection, so the three-screw pump is not recommended for transferring thinner liquids. Try to avoid using it for multi-phase operations as well. The screws have different types depending on the number of screws added to the system. These types include the following:

  • Five Screw Pump
  • Four Screw Pump
  • Single Screw Pump
  • Three Screw Pump
  • Two Screw Pump


The Alfa Laval Twin Screw Pump designed for process flexibility to handle both product transfer and cleaning in place, with the ability to move seamlessly between the two. Its optimised design, carrying approvals including 3A,FDA and EHEDG, reduces contamination risks and CIP cycle times, cutting cleaning and waste management costs. There are three options for the Alfa Laval Twin Screw cartridge seal, single, single flush and double.