Screw Pump

Screw pump is one of the oldest type of pump. It is a kind of rotary, positive displacement pump that has one or more screws to transfer high or low viscosity fluids along an axis.

How does a Screw Pump works?
In a screw pump, the liquid is carried between the screw threads on one or more rotors. As the screws rotate and mesh, the liquid is then displaced axially. In other types of rotary pumps, the liquid moves circumferentially. But the screw pump has an axial flow pattern and low internal velocities. Screw pump has two different types of rotors: the single rotor and the multiple rotor. The multiple rotor is further divided into two: timed and untimed categories. Timed rotors rely on outside means for supporting the forces acting on the rotors. Untimed rotors rely on precision and accuracy of the screw forms for proper mesh and transmission of rotation.

Types of Screw Pumps:

• Single Screw : The single screw pump also known as the Archimedian screw. This pump is at least 2,000 years old and is still used in irrigation and agricultural applications. It is quite large. It is normally used as a water-raising pump. It can also be used for handling liquids containing solids in suspension with either horizontal transport or vertical lift.
  
  
• Intermeshing Screw Pump : This screw pump is commonly called a rigid-screw pump. This type of pump is suitable for a wide range of sizes, and can be run at high speeds. The larger sized screw pumps are used for bulk handling of oils and similar fluids. The basic type is suitable for handling most clean fluids with low flow velocities and at low heads.
  
  
• Eccentric Screw Pump : This screw pump is versatile. It is capable of handling a variety of liquids and products with high efficiency. It can handle slurries, pastes, viscous liquids, solids in suspension and delicate products.

Features of Screw Pump:

• Wide range of flows and pressures.
• Wide range of liquids and viscosities.
• Built-in variable capacity.
• High speed capability which allows freedom of driver selection.
• Low internal velocities.
• Self-priming with good suction characteristics.
• High tolerance for gases and entrained air.
• Minimum foaming or churning.
• Low mechanical vibration and quiet operation.
• Rugged, compact design and easy to install and maintain.
• High tolerance to contamination compared to other rotary pumps

Applications of Screw Pump:
Screw pumps are used in several applications that include a wide range of markets such as:

• Utilities Fuel Oil Service
• Industrial Oil Burners
• Lubricating Oil Service
• Chemical Processes
• Petroleum and Crude Oil Industries
• Power Hydraulics
• Raw Sewage Lifting
• Sewage Lift Up
• Stormwater Pumping
• Land Drainage
• Flood Control