The selection of a screw pump should follow a systematic approach. First, the basic type and specifications of the pump should be determined based on the properties of the liquid being pumped (such as viscosity, corrosiveness, and particle content), the required flow rate, and pressure.
The maximum output pressure (maximum operating pressure) of a screw pump is primarily determined by its structure. For example, a single-screw pump can be determined based on the number of leads (stages) of the bushing (stator). The pump speed selection needs to consider the viscosity, corrosiveness, abrasiveness of the medium, and the pump's specifications. High-viscosity or particulate media typically require lower speeds to ensure reliable operation and reduce wear. The material combination of components in contact with the medium (such as bushings and screws) must be selected based on the corrosiveness, lubricity, and temperature characteristics of the medium, which is crucial for the pump's lifespan and applicability.
After clarifying the above basic parameter requirements, the type of screw pump (such as single-screw, twin-screw, or triple-screw) can be initially selected. For example, single-screw pumps are suitable for conveying high-viscosity media containing a large number of particles or fibers, and cause little damage to the media structure; the flow rate of twin-screw pumps is affected by viscosity, and the leakage is inversely proportional to the viscosity; three-screw pumps are mostly used to convey lubricating oils, and the internal or external bearing structure is selected according to the temperature and lubricity of the media.
