Double screw pump is a type of positive displacement pump that has two synchronized rotating screw profiles. The fluid is continuously and smoothly transported forward through the closed volumes created between these two screws. Thanks to the rotation of the screw profiles without touching each other, the pump offers reliable performance in both low-viscosity liquids and high-viscosity fluids containing particles. This contactless working principle helps keep friction at a minimum level and preserves the integrity of the product.
The linear flow generated by the pump during operation prevents the occurrence of unwanted turbulence and shear forces in sensitive processes. This feature provides a significant advantage, especially in sectors where product integrity is critical, such as food and pharmaceuticals.
One of the prominent working principles of double screw pumps is their ability to provide stable flow over a wide range of speeds. While precise and controlled transfer is possible at low speeds, higher flow rates can be achieved at high speeds. This wide operating range allows the pump to undertake both transfer and cleaning (CIP) tasks on a single line. The ability to operate the pump in reverse or in the same direction during CIP reduces the need for additional pumps, valves, or redirecting systems.
With advantages such as energy efficiency, low maintenance requirements, stainless steel body options, and process flexibility, double screw pumps stand out as versatile equipment in modern production lines. Their ability to deliver stable performance even in high viscosity, gas-liquid mixtures, or fluids with large particles makes this type of pump ideal for various industries.
Double screw pumps have advanced designs that stand out in terms of durability and process flexibility within the positive displacement pump class. The working principle, based on the synchronized rotation of two screws without contact, ensures that the flow progresses continuously, smoothly, and precisely. This structure allows the pump to deliver the same stable performance in both high-viscosity products and low-viscosity fluids.
One of the most striking features of these pumps is their wide pressure and speed range. The body structure suitable for operation up to 20 bar provides reliable performance in processes requiring high pressure. The wide speed range allows the same pump to be used in controlled applications requiring slow flow as well as in high flow demand situations. Thus, multiple operations can be performed with a single pump on production lines.
Double screw pumps also offer significant advantages in cleaning processes. The internal design that fully complies with CIP and SIP systems prevents liquid accumulation within the pump body. During cleaning, the fluid can be completely drained from the pump, and additionally, the pump can be operated during CIP, eliminating the need for extra equipment. This feature helps simplify the line and reduce maintenance costs.
In terms of durability, the use of stainless steel body, needle bearing structure, and high-strength 17-4PH shaft stands out. These materials offer a long service life against temperature, pressure, and vibration effects. The connection of the screws to the shaft with a key facilitates assembly and disassembly processes while shortening maintenance times. Additionally, the ability of the pump to operate in both directions provides maximum flexibility in process flows.
The option to choose sealing options as single or double seals makes it easier to adapt the pump to different process conditions. Washable sealing systems can be added when necessary, and all models are compatible with this feature. The absence of bearings and screws in areas that come into contact with the liquid prevents product contamination and extends the service life of the seals and bearings.
These technical advantages make double screw pumps a reliable, efficient, and long-lasting transfer solution in modern production lines. They enhance process safety and minimize maintenance requirements.
Performance Advantages in High Viscosity, Solid Particulate, and Gas-Liquid Mixtures
Double screw pumps are one of the reliable solutions preferred in many industries due to their stable performance in processes with challenging fluid structures. The contactless and synchronized rotation of the screw profiles ensures that the fluid is transported with a smooth and linear flow. This working principle facilitates the transfer of products with different viscosities and allows the transportation of mixtures containing large particles without compromising their integrity.
One of the biggest challenges encountered with high-viscosity fluids is the intake of the flow into the pump. The powerful self-priming feature of double screw pumps largely eliminates this issue. Even at low speeds, thick products can be easily drawn in by the pump and delivered with a steady flow. Thanks to the pump's low shear application, the structural properties of viscous products are preserved; this is particularly critical for product quality in the food, cosmetics, and chemical sectors.
In fluids containing solid particles, the design of the screws that can create large volumes stands out. The pump can pass solids up to a certain particle size without compressing or breaking them. Thus, fruit particle beverages, particulate mixtures, fibrous liquids, or process fluids carrying particles can be transferred smoothly. This contactless flow structure also reduces wear on process equipment, extending the operational life of the line.
In gas-liquid mixtures, the stable flow capability of double screw pumps provides a decisive advantage. In fluids containing gas bubbles, some positive displacement pumps can cause flow fluctuations, while double screw pumps transport these mixtures more homogeneously. This feature increases operational reliability in sectors such as food, chemicals, and energy, where process continuity is crucial.
A wide speed range is another factor that supports performance in challenging fluids. At low speeds, a precise and controlled flow is provided, while at high speeds, larger flow rates can be achieved. This flexibility allows the same pump to perform different process tasks that include both high viscosity and low viscosity. As a result, the need for separate pumps in the production line decreases, and operational costs are reduced.
In conclusion, twin-screw pumps offer superior performance across a wide variety of processes thanks to their ability to adapt to challenging fluid conditions. They provide a stable, reliable, and product-friendly transfer regardless of high viscosity, solid particles, or gas-liquid mixtures.
Operational Advantages of CIP and SIP Compliant Design
One of the most significant advantages of twin-screw pumps is their complete compatibility with both CIP (Clean-in-Place) and SIP (Sterilize-in-Place) systems. This feature provides significant gains, especially in the food, pharmaceutical, beverage, and chemical industries, where hygiene and process continuity are critical. The ability to completely drain the pump body without leaving any liquid inside enhances the effectiveness of cleaning and sterilization processes while ensuring operational efficiency in the production line.
The self-cleaning capability of the pump during CIP eliminates the need for additional CIP pumps, bypass lines, or extra valve systems. Twin-screw pumps provide more effective washing within the line by circulating the cleaning liquid at low speeds with precision and at high speeds with strong flow throughout the system. This versatility shortens cleaning times and optimizes energy and water consumption.
SIP compatibility comes from the pump's resistance to high temperatures. The stainless steel body, construction that controls thermal expansion, and suitable sealing options ensure that the pump exhibits full resistance to sterilization steam. This feature is particularly important for reliability, hygiene, and product safety in pharmaceutical and biotechnological processes.
To prevent any fluid from accumulating at blind spots in the pump during CIP and SIP, the internal volumes are designed to be smooth and continuous. The absence of bearings or screws in areas that come into contact with the liquid prevents dirt accumulation and ensures that cleaning liquids reach all surfaces evenly. Thus, the microbial load and contamination risks on process equipment are minimized.
The dual-direction operation capability of the twin-screw pump during cleaning is also a significant advantage. This feature allows the cleaning agent to flow in both directions, effectively rinsing the internal surfaces of the pump. At the same time, it enables the pump to be used without requiring configuration changes when the flow needs to be reversed in production lines.
These technical advantages mean less downtime, lower maintenance costs, and higher hygiene assurance for businesses. Being able to perform both transfer and cleaning functions with a single pump, especially in sensitive production lines, makes operational processes more compact, economical, and reliable.
Large Screw Range or Small Screw Range? Choosing the Right Configuration
The performance and process compatibility of twin-screw pumps vary significantly depending on the screw range. Therefore, selecting the correct configuration is a critical step that determines both the efficiency of the pump and its ability to work in harmony with the product. Depending on process requirements, either a large or small screw range can be preferred, and each option has its unique advantages.
A large screw range allows for the formation of larger volumes between the screws. These larger volumes provide the pump with a higher flow rate and greater particle carrying capacity. Large screw ranges are more advantageous for processes involving fruit particle beverages, mixtures containing solids, thick products, or processes where particle size is critical. However, the larger volume may result in lower pressure resistance compared to a small screw range. This situation may limit performance in applications requiring high pressure. Therefore, a large screw range is an ideal choice for low to medium pressure processes that require high flow rates and high particle permeability.
A small screw range, on the other hand, allows for the formation of narrower volumes between the screws. This structure enables tighter transport of the fluid and allows the pump to generate higher pressure. Small screw ranges are more suitable for high-pressure applications and processes that require high temperature and more intense control. However, due to the narrowing of volumes, the size of the particles that can be pumped is limited, and the flow capacity is lower compared to a large range. Nevertheless, a small screw range increases process precision by providing stable flow in high-viscosity fluids.
When choosing a configuration, the viscosity range of the process, desired pressure values, particle size to be transported, and flow requirements in the production line should be evaluated together. The correct choice increases the energy efficiency of the pump and reduces maintenance needs, thereby lowering operating costs in the long run.
In conclusion, the choice between a large or small screw range is not a single correct answer; it is the right engineering choice optimized according to process conditions. Both structures are part of the flexible design of the twin-screw pump and can provide high performance according to the production needs of the business.
Material Structure, Sealing, and Durability Features in Twin-Screw Pumps
Twin-screw pumps are high-engineering products designed to withstand challenging process conditions. The key elements that ensure the long-lasting, reliable, and hygienic operation of these pumps are the quality of the materials used, sealing technology, and mechanical durability features. Each element directly affects the performance of the pump, making the correct configuration during the selection process critically important.
The pump body and all surfaces in contact with the liquid are generally made of stainless steel. This material exhibits high resistance to corrosion and ensures safe use in hygiene-demanding sectors such as food, pharmaceuticals, and chemicals. One of the most significant advantages of the stainless structure is its resistance to high temperatures and aggressive cleaning chemicals. Thus, the pump maintains its performance during both production and CIP/SIP cycles.
The 17-4PH stainless steel used as shaft material stands out with its high strength and hardness values. The wide diameter shaft design reduces vibrations while ensuring even distribution of mechanical loads within the pump. This structure directly extends the lifespan of sealing elements and bearings. The absence of additional contact points such as bearings or screws in the internal volume of twin-screw pumps prevents both wear and contamination buildup. This feature offers significant advantages in hygienic processes.
The bearing system uses high-precision heavy-duty needle bearings. These bearings provide stable performance under high speed, high pressure, and long-term operational conditions. The oil-lubricated bearing design facilitates maintenance operations and increases the reliability of the pump. Additionally, the ability to lubricate the bearings from the front provides more effective protection against temperature and pressure changes.
Sealing systems are a critical component for the pump to operate in accordance with process conditions. Twin-screw pumps offer single or double mechanical seal options. Washing seal applications are particularly preferred in situations where high temperature, aggressive liquids, or contamination risks are critical. The compatibility of all models with subsequent washing seals makes it easier to use the pump in different processes. When these durability features come together, twin-screw pumps offer a long-lasting solution with both mechanical reliability and hygienic design. This structure minimizes the risks of wear, contamination, and mechanical failure, meaning sustainable performance and low maintenance costs for businesses.
Applications of Twin-Screw Pumps by Industry
Twin-screw pumps are among the preferred solutions for reliable fluid transfer in many industries due to their versatile structures and wide operating range. Their ability to transport both low and high viscosity products, mixtures containing solid particles, or fluids in gas-liquid phases with stable and pulsation-free flow makes these pumps indispensable in various sectors. Below, the main application areas of twin-screw pumps in key industries are detailed.
Food Industry
In food production, hygiene, product integrity, and process continuity are extremely important. Twin-screw pumps transport sensitive fluids such as dairy products, fruit pulp beverages, syrups, yogurt derivatives, and viscous food products without compromising their structural properties. The pulsation-free flow principle minimizes product deformation. CIP and SIP compatibility accelerates cleaning processes, helping to maintain high hygiene standards. The stainless steel body and smooth inner surfaces provide an additional advantage in terms of food safety.
Automotive
In the automotive sector, processes such as production lines, testing systems, and paint applications require precise fluid management. Twin-screw pumps enable the safe transfer of hydraulic oils, cooling fluids, high viscosity lubricants, or chemical specialties by providing stable pressure and continuous flow. They prevent vibration and flow variability in impact-sensitive processes, enhancing production quality. Additionally, the durable material structure offers minimal maintenance needs in long-term operations.
Marine
Marine applications require the use of durable equipment due to high humidity, salinity, and variable temperature conditions. Twin-screw pumps provide reliable flow in ballast water, bilge water, fuel transfer, and cooling systems. The corrosion-resistant stainless body offers long life against aggressive conditions in saltwater and marine environments. The self-priming capability allows pumps to draw liquids from tanks at various levels in ship systems.
HVAC
In heating, cooling, ventilation, and hot water applications, fluids must be transported in a controlled and stable manner. Twin-screw pumps provide stable performance in HVAC systems thanks to their high-temperature and pressure-resistant structures. The pulsation-free flow structure reduces pressure fluctuations in the system, extending equipment life. With its design that enhances energy efficiency, the pump is a reliable solution in comfort climate control and industrial heating-cooling processes.
Petrochemical and Pharmaceutical
The petrochemical and pharmaceutical industries involve processes that require both high temperature and chemical resistance. Twin-screw pumps can transport corrosive liquids, solvents, high viscosity chemicals, or multiphase fluids in a pulsation-free and controlled manner.
The advanced structure of sealing systems ensures the leakage safety required by these sectors. In pharmaceutical processes, CIP/SIP compatibility and smooth inner surfaces provide significant advantages for hygienic operation.
Metal Industry
In metal processing lines, lubricants, coolants, chemical specialties, and high viscosity fluids are used intensively. Twin-screw pumps provide stable flow in metal formulation processes with their high-pressure resistant structures. The wear-resistant material structure offers long life and low maintenance needs in continuously operating production lines. The absence of performance loss even at high temperatures and high viscosities increases efficiency in metal processing factories.
Energy
In energy production, applications such as cogeneration, heat recovery systems, and turbine auxiliary circuits require critical flow control. Twin-screw pumps reliably transport challenging fluids such as high viscosity oils and heat transfer liquids. The wide speed range optimizes system performance by meeting different flow requirements. Low maintenance needs contribute to the continuity of energy infrastructures.
Textile
In textile processes, dyes, chemical specialties, viscous mixtures, and heating-cooling fluids must be managed precisely. Twin-screw pumps provide pulsation-free flow, ensuring homogeneity in printing, dyeing, and finishing lines. Energy efficiency and accurate flow control enhance product quality. Their chemical-resistant structure offers long-term usage advantages in textile businesses.
Cost Advantages and Operational Savings Provided by Twin-Screw Pumps
Double screw pumps stand out as an economical solution in modern production lines with their comprehensive advantages in terms of process efficiency and operational costs. The ability to perform both transfer and CIP functions with a single pump significantly reduces equipment investment costs. The elimination of the need for additional CIP pumps, diversion valves, or complex piping installations provides direct savings in initial installation costs.
The pulsation-free and continuous flow structure offered by the pump design enhances the stability of production processes. The reduction of flow fluctuations improves production quality while also decreasing the mechanical stress on system components. This situation extends the lifespan of the equipment and contributes to lower maintenance and repair costs. Additionally, the absence of bearings or screws in areas of the pump that come into contact with the liquid minimizes wear risk and reduces maintenance requirements.
The self-priming capability of double screw pumps can eliminate the need for vacuum systems or auxiliary suction pumps in production lines. This feature particularly increases operational efficiency in lines processing high-viscosity products. The ability of the pump to operate over a wide speed range allows for different flow ranges to be met with a single piece of equipment. This enables businesses to save on energy consumption and allows for more flexible planning in production processes.
In terms of energy efficiency, double screw pumps are advantageous compared to many alternatives. The positive displacement working principle allows for stable flow to be achieved with low energy even in fluids with high viscosity or containing particles. The reduction of system losses positively reflects on operational costs in the long term.
Thanks to their hygienic design, they require less water, fewer chemicals, and shorter cleaning times during CIP and SIP processes. The shortening of cleaning times contributes to a reduction in downtime and an increase in overall efficiency across the facility. At the same time, the reduction in resources spent on cleaning provides direct savings in operating expenses.
When all these factors are considered, double screw pumps offer significant advantages to businesses not only in terms of technical performance but also in terms of total cost of ownership. With less equipment, lower energy consumption, reduced maintenance requirements, and increased process efficiency, total operational costs decrease while production continuity increases.
Differences of Double Screw Pumps Compared to Other Positive Displacement Pumps
Although double screw pumps fall into the category of positive displacement pumps, they exhibit significant differences from many traditional pump types in terms of design and performance. These differences make double screw pumps a more advantageous solution, especially in applications involving the transportation of challenging fluids, processes requiring hygiene, and high-pressure needs. The most notable difference is that the screws operate in synchronization without touching each other. In lobe or gear pumps, the surfaces in contact can damage the integrity of the product due to higher shear forces. In double screw pumps, however, the fluid is transported steadily, linearly, and without pulsation. This structure provides significant advantages, especially for sensitive food products, particulate mixtures, and viscous fluids.
In terms of pressure and speed range, double screw pumps offer a wider operating area. The robust body structure, which can withstand pressures up to 20 bar, ensures stable performance in processes requiring high pressure. Lobe pumps are generally suitable for lower pressure levels and can create flow fluctuations in gas-liquid mixtures. Double screw pumps manage these mixtures more homogeneously and maintain process continuity.
The hygienic design difference is also an important advantage. Since there are no bearings or screws on the inner surfaces of double screw pumps, the risk of contamination in the food and pharmaceutical industries is minimized. These pumps are fully compatible with CIP and SIP processes and do not retain liquid within the system during cleaning. This feature makes double screw pumps stand out in processes where hygiene levels are critical. In terms of sealing technology, double screw pumps are also more flexible. Various mechanical seal options such as single, double, or flushed seals can be adapted to different chemical resistance levels. This flexibility may not be available in all models of other positive displacement pumps, and additional equipment may be required for process changes.
There are also significant differences in energy efficiency. The self-priming capability of double screw pumps provides stable flow with low energy even in fluids with high viscosity or containing particles. Gear pumps may consume more energy or lose flow stability under high viscosity conditions. This situation directly affects operational costs.
Wear resistance is also a highlight of double screw pumps. The non-contact of the screws reduces wear risk and contributes to extended maintenance intervals. Gear pumps or lobe pumps may require more frequent maintenance due to their contacting surfaces.
In conclusion, double screw pumps excel over other positive displacement pumps in areas such as hygiene, pressure resistance, flow stability, adaptability to a wide viscosity range, and ease of maintenance. Therefore, they are increasingly preferred in modern production lines for both process safety and economic operational advantages.
Criteria to Consider When Selecting a Double Screw Pump
The selection of a double screw pump represents a critical engineering decision that directly affects process efficiency. Therefore, when choosing a pump, not only flow and pressure values but also the structure of the fluid, process requirements, and operating conditions should be comprehensively evaluated. The correct configuration reduces operational costs and increases system reliability.
The first criterion to be evaluated should be the physical properties of the fluid. The viscosity, temperature, density, particle size, and phase mixture of the fluid directly affect pump performance. A wide screw range is preferred for high-viscosity or particulate products, while a narrower screw range would be more suitable for applications requiring high pressure. The chemical structure of the fluid also plays a decisive role in the selection of body material and seal type.
The pressure and flow requirements of the process are also important factors in the selection. Since twin-screw pumps can operate over a wide speed range, it is possible to meet different flow needs with a single piece of equipment. However, the total pressure loss in the line, the piping structure, and the operating temperatures must be taken into account. Correct calculation of these values ensures that the pump operates in harmony with the system.
The sealing system is another important criterion that determines the suitability of the pump for the application. When choosing between single, double, or flushed mechanical seal options, the chemicals of the fluid, temperature level, and contamination risk should be considered. In hygienic processes, sealing safety becomes even more critical.
In sectors requiring hygiene, CIP and SIP compatibility must also be evaluated. The internal surfaces of the pump must be smooth, the liquid should not accumulate in the body, and it must be completely emptied during cleaning, which are mandatory criteria, especially for food and pharmaceutical industries. A pump design that can operate at high speed during CIP increases cleaning efficiency while reducing the need for additional equipment in the system.
Material durability and mechanical structure determine long-term operational reliability. The corrosion resistance of the body material, the strength of the shaft structure, the durability of the bearing system, and the overall construction quality directly affect the service life of the pump. Therefore, material selection should be made considering the operating temperature, chemical resistance requirements, and process cycle.
Finally, the maintenance and operation policies of the business also shape the pump selection. Pumps that can be easily disassembled and assembled, have clear grease or lubrication requirements, and can quickly carry out the seal replacement process reduce maintenance times. This significantly contributes to reducing downtime in production lines and lowering overall operating costs.
When all these criteria are evaluated together, a twin-screw pump selected with the right engineering approach increases process safety, enhances energy efficiency, and optimizes operating costs in the long run. Therefore, the pump selection process requires a comprehensive evaluation from both technical and economic perspectives.