Kirjoittaja Aihe: SCREW PUMP APPLICATIONS IN PIPELINES (Luettu 206 kertaa)

upamfva · 17.03.23 - 08:19

SCREW PUMP APPLICATIONS IN PIPELINES

As complexity grows in processes and in transfer of fluids in pipelines and plants, screw pump technology has attracted increased interest from engineers and operators in the industry. The emphasis to increase energy efficiency while improving flexibility and driving down operating costs is leading the way. It is now the time to critically revisit conventional thinking about pump selection and take a fresh look at the evolution of screw pumps, how they could improve economics and safeguard the vitality of critical processes in plants and transfer systems.To get more news about SEEPEX Pump Part, you can visit hw-screwpump.com official website.

Let’s discuss pump types with multiple screws, which are different from the often used single screw or progressive cavity pump. In principle, screw pumps are part of the positive displacement family, and as such, are designed to displace flow in direct proportion to the rotary speed of the pump.
The tight cavities formed when the profiles of the screws are meshing, transport fluids from suction to discharge, building up pressure enough to overcome the downstream system back pressure. The screws in the pump are the pumping elements where the driven screw or power rotor transfer the torque to one or several idler screws both mechanically and hydraulically. The smooth opening and closing pump cavities result in a pump flow with very limited pulsations and noise.

The pump screws or rotors are designed to eliminate any axial hydraulic thrust either by using balance pistons or having the screws in an opposed flow arrangement. Eliminating thrust bearings helps greatly to simplify the pump design and exclude potential wear areas. The multiple screw pump design is self-priming, can work with very low suction pressure, is also gas tolerant and able to handle free and entrained gases without loosing prime. Low internal fluid velocity and the gentle meshing of the rotors also contribute to very low shear rates, which is especially important for shear sensitive fluids or for different kinds of oil emulsions.

The operational flexibility of the multiple screw pump is also manifested by its ability to work over a very large viscosity range – from light hydrocarbons to residues and bitumen. The screws are normally case hardened for improved wear resistance, and customized coating are often used to protect the rotor bores, the rotor liner, or pump casing.

The Leistritz family of screw pumps with multiple rotors includes the following pump designs which are increasingly used not only in hydrocarbon related industries and applications, but also in chemical and petrochemical applications. Each series of pump has its specific set of operational advantages and possibilities. To find the right type of pump for an application is not only technically important for the process, but also a cost optimization opportunity.
This unique pump design relies on two screws, one drive and one idler screw, which are radially supported by large bushings lubricated by the pumped fluid. The bearing journals are also part of the axial thrust balance configuration where discharge pressure one side of the journal and suction pressure on the other side creates pressure balance and also provides the bearing journal with liquid for lubrication and cooling.

The torque transfer from one rotor to the other is by means of rolling (as opposed to sliding) contact over the screw profiles, which is important for good wear resistance. The rotors are at the
same time positioned without any radial support from the rotor bore, which also makes to pump very resistant to abrasive wear and suitable for fluids with low lubricity.