Working principle: types and features

There are several types of screw pumps, which differ in the number of screws and design features:

• Single screw pumps: the simplest in design, but less efficient than multi-screw pumps.
• Twin-screw pumps: provide high performance and smooth running.
• Three-screw pumps: have the highest performance and can pump liquids with high viscosity.
• In addition, screw pumps can be single-stage or multi-stage. Multistage pumps allow for high head delivery.

Materials for manufacturing

The choice of material for a screw pump depends on the properties of the fluid to be pumped and the operating conditions. The following materials are most commonly used:

• Cast iron: for pumping neutral liquids.
• Stainless steel: for aggressive media.
• Special alloys: for particularly difficult operating conditions.

Advantages of screw pumps:

• Self-priming: allows pumping liquid from great depths without the need to pre-fill the pump.
• Gentle operation: minimises damage to products, which is especially important for the food and pharmaceutical industries.
• Wide viscosity range: can pump liquids from water to thick pastes.
• Durability: due to the absence of valves and seals that are subject to wear and tear.
• Dry-running capability: they do not fail in the event of a short-term absence of liquid in the casing.
• Energy efficiency: high efficiency and low energy consumption.

Applications: specific examples

• Pharmaceuticals: sterile pumps for transferring medicines and cosmetics.
• Chemical industry: pumps with anti-corrosion coating for aggressive media.
• Oil refining: pumps for pumping viscous oil products at high temperatures.
• Pulp and paper industry: pumps for pumping abrasive slurries.
• Construction: pumps for concrete and other building mixtures.
• Food industry: pumps made of food grade stainless steel for pumping food products.

Choosing a screw pump: key criteria

• Characteristics of the pumped liquid: viscosity, temperature, abrasiveness, chemical activity.
• Required capacity: the volume of liquid to be pumped per unit of time.
• Required head: the height of the liquid lift.
• Operating conditions: ambient temperature, vibration, dust.
• Materials from which the pump is made.

Conclusion

Screw pumps are a versatile and reliable solution for many industrial applications. Their wide range of applications, high efficiency and durability make them indispensable in modern production. When choosing a screw pump, all of the above factors must be taken into account to ensure optimum performance of the equipment.