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What Is Screw Pump?
A screw pump is a positive displacement (PD) pump that uses one or more screws to move fluid solids or liquids along the screw axis. In its simplest form, a single screw rotates in a cylindrical cavity, moving the material along the screw's spindle.To get more news about NETZSCH Pump Accessories, you can visit hw-screwpump.com official website.

This ancient design is still used in many low-tech applications, such as irrigation systems and farm machinery used to transport grain and other solids.

The evolution of the screw pump has led to a variety of multi-axis technologies in which carefully crafted screws rotate in opposite directions or remain stationary in a cavity. The cavity can be profiled, creating cavities in which the conveyed material is "locked-in".

In offshore and marine installations, a three-spindle screw pump is widely used to pump viscous fluid under high pressure. Three screws propel the pumped liquid in a closed chamber. As the screws rotate in opposite directions, the pumped liquid moves along the spindles of the screw.

Three-spindle screw pumps are used to transport viscous liquids with lubricating properties. They are suitable for a variety of applications such as fuel injection, oil burner, supercharging, hydraulic, fuel, lubrication, circulation, delivery, and so on.

Positive displacement pumps have several advantages over centrifugal pumps. The pumped fluid moves axially without turbulence, preventing foaming that would otherwise occur with viscous liquids. You can also pump higher viscosity liquids without losing flow rate. Changes in the pressure difference also have hardly any effect on PD pumps compared to centrifugal pumps.

How Do Screw Pumps Work?
Screw pumps operate using two counter-rotating screw rotors which are engineered so that they rotate "towards each other". This traps the gas in the space between the "screws" of their rotors. As the screws rotate, this trapped volume decreases which not only compresses the gas but move it towards the exhaust.

In the first case, mechanical bearings support the rotors at both ends. The cantilever design solution supports the rotors at the high-pressure end and the rotors can be cooled internally. A motor drives the two rotors via a gear.

Gear and the bearings are lubricated but separated from the pumping mechanism ('vacuum generator') via shaft seals or labyrinth seals, thus the compression is oil-free. The rotors have no mechanical contact between each other and the pump housing, resulting in zero mechanical wear.

To keep the installed electrical power low, modern pumps are driven by an electronic frequency converter and rotate slower at pressure ranges near atmospheric pressure. Some versions use so-called blow-off valves instead to keep the rotating speed constant also at high pressures.