A screw pump is a type of positive displacement pump that uses two or more screws that intermesh to pressurize fluids and move them in a system. The screws take in fluid then push it out from the other side while increasing its pressure.
Types of the Screw Pumps
There are two main types of screw pumps in common use today:
- Two/Double screw pump (twin screw pump) – These pumps operates by using two intermeshing screws as described above. The pump is often equipped with timing gears located outside the pumping chamber that are lubricated with oil in order to ensure the two screws are rotating properly. Due to the design, the screws are not required to be in direct contact with each other which helps extend the life of the pump.
- Three screw pump (triple screw pump) – They utilize one driving screw intermeshed with the other two screws to create pressure and move fluid. The screws do come into contact with each other, which often limits the pump to handling only clean liquids.
There is also a three spindle screw pump commonly used in the offshore and marine industries to move high-pressure viscous fluids. Three screws that rotate in opposite directions drive the liquid forward in a closed chamber and along the screws’ spindles. The pumps are also used to transport viscous fluids with lubricating properties and in a variety of applications including boosting, burners, circulating, fuel-injection, lubrication, oil hydraulics, and others.
Less commonly used is the single screw pump, which uses only one screw and has more limited capabilities.
Screw Pump Applications
Due to their ability to provide high flow rates even in viscous liquids, screw pumps are ideal for fuel transfer, elevators, and other similar industrial applications. Single screw pumps, or Archimedean screw pumps, are used for simple water movement such as for sewage inlet pumps, storm water pumping, drainage pumping, and to move industrial waste water.
Screw Pump Application Ranges
- Flow Rate Ranges – 50 to 15,000 gallons per minute, 189 to 56,781 liters per minute
- Total Head (Pressure) Ranges – 50 to 4,500 psi, 3 to 310 bar
- Horse Power Ranges – 5 to 5,000
Pro’s and Con’s of Screw Pumps
Screw pumps offer the highest flow rate of positive displacement pumps which makes them a great choice for those who work with hard to move liquids and need to move them as quickly as possible, as in many oil and gas applications moving fuels, oils, and other high viscosity liquids. Screw pumps are also a good choice for two phase liquid and gas mixtures. However – with the exception of single screw pumps – they are not ideal for moving clean liquids at steady paces. In addition, the complexity of screw pumps often comes with increased maintenance and shorter equipment when compared to more simple pumps.
Advances in Screw Pumps
Blackmer S Series Screw Pumps – These amazing new pumps are self-priming double ended positive displacement pumps offered with or without external timing gears and bearings. Available in double and triple screw models, they provide axial balancing of rotating screws and eliminate metal-to-metal contact with advanced timing technologies.
NETZSCH NOTOS Multi Screw Pump – These screw pumps are designed to work with low to high lubricant fluids, low to high viscosity, shear sensitive, and even chemically aggressive media. They operate by use of a drive screw intermeshing with a driven screw that transfers torque from one component to the other. Available as double, triple, and even quadruple screw pumps.
Maag S Series Screw Pump – These double-suction, self-priming screw pumps come with external bearings and a timing gears transmission. The pumps are ideal for the delivery of fluids free of solid substances and/or with little abrasiveness. They also come with non-timing gear transmission and as multi-phase pumps.
For More on Screw Pumps
Screw Pump White Paper – Enter your contact info here to download our very own white paper on what a screw pump is. We discuss how the name fails to recognize the different product configurations, as well as the advantages, uses, and design considerations.
Archimedes’ Screw – Screw pumps date back to the Archimedes screw, which was invented by the Greek scientist in around 300 BC. The screw was used to move water for irrigation using one screw fit into a cylinder. Today, a few types of systems still use this design, although most use at least two screws.
Engineer’s Edge – See the schematics for several different types of screw pumps here, as well as get an inside opinion on the pro’s and con’s of screw pumps.
Intelligent Pumps for the Digital Oilfield Global Market Research Study – ARC predicts the future of the market in this five year study and includes interesting facts in relation to pumps.