In the modern industrial production system, rotor pumps and screw pumps, as typical representatives of positive displacement pumps, are widely used in industries such as chemical engineering, food, and pharmaceuticals due to their characteristics of being able to convey high-viscosity media and having relatively high delivery pressures. However, there are significant differences between the two in terms of structural design, performance, and maintenance costs, and these differences directly affect their applicability under different working conditions.
I.Differences in Structural Design
The core component of Bonve's rotor pump is an eccentric streamlined rotor. This design is based on the principles of fluid dynamics, enabling it to push the fluid with the minimum resistance and reduce energy consumption. There are no dead corners for fluid flow inside the pump body, which can prevent material residue. The parts through which the material flows are made of special alloy metal materials, which have been surface hardened and anti-corrosion treated to adapt to complex media. The mechanical seal, combined with the water cooling system, can ensure the safety of the mechanical seal during long-term operation or idling. The optimized gaps between the rotors and between the rotors and the pump body can not only ensure fluid conveyance but also prevent component friction, thus extending the service life of the equipment. This precise design allows the rotor pump to operate stably even under complex working conditions.
The screw pump relies on the rotation of the screw inside the rubber stator to convey materials. The zero-clearance fit between the two theoretically facilitates material extrusion, but there are many problems in practical applications. Due to the non-streamlined curved surface of the screw pump and numerous defects inside the cavity, it is impossible for it to be a hygienic-grade pump. The damage to the tetrafluoroethylene or rubber on the cavity wall is more likely to contaminate the conveyed medium. The sleeve of the screw pump is made of rubber, which is not wear-resistant and is a vulnerable part. Comparatively speaking, the long-term cost is very high. In addition, the manufacturing process of the rubber stator affects its performance, and the disassembly and installation of the screw pump are complex, resulting in high maintenance difficulty.
II.Differences in Performance
· Hygienic Performance
In industries with extremely high hygienic requirements, such as the food and beverage and pharmaceutical industries, Bonve's rotor pump has significant advantages. Its structure with no dead corners and all-metal parts through which the material flows complies with international hygienic standards such as GMP, FDA, and EHEDG. For example, when conveying milk and cream in the dairy production process, it can prevent material residue and the growth of bacteria; when conveying liquid medicine in the pharmaceutical industry, it will not chemically react with the medicine. Moreover, its structure is convenient for in-line cleaning (CIP), and thorough cleaning can be achieved through the alternating flushing of acid-base solutions and clean water. In contrast, the non-streamlined curved surface and complex internal structure of the screw pump make it difficult for the cleaning solution to cover all areas, leaving dirt residues easily. After the rubber stator ages and is damaged, the debris will contaminate the materials, so its application is limited in industries with high hygienic requirements, and it is impossible for it to be a hygienic-grade pump.
· Conveyance Efficiency and Stability
The rotor pump can stably output the flow rate by precisely controlling the eccentric movement of the rotor and the gaps. When conveying high-viscosity media, it can adjust the rotational speed according to the demand to achieve a linear change in the flow rate, and the flow pulsation is small, making it suitable for processes with high requirements for flow stability, such as the batching and conveying of coatings. The screw pump has a high initial operating efficiency, but with continuous use, the rubber stator wears and deforms. For example, in the sewage treatment industry when conveying sludge containing impurities, the conveying efficiency may decrease by 30%-50% after running continuously for 6 months, and frequent adjustments or replacements of components are required.
· Idling Adaptability
The mechanical seal water cooling system and gap design of the rotor pump give it strong idling adaptability. Even if it idles for 24 hours, it can protect the mechanical seal and avoid severe friction between components. The screw pump cannot idle. If it idles, the inner cavity of the rubber stator will be completely crushed. The stator of the screw pump is made of rubber, and there is a zero-clearance between the screw and the stator. It relies on the rotation of the screw to extrude and convey the material. During operation, the extrusion of the material and the rubber stator generates friction, causing the stator to gradually heat up, expand, and deform. The gap between the screw and the stator becomes larger, and the material flows back to the low-pressure area. The conveying efficiency becomes lower and lower, failing to meet the working condition flow rate, and the stator needs to be replaced. Therefore, the stator is a vulnerable part.
III. Differences in Maintenance Costs and Service Life
· Vulnerable Parts and Replacement Frequency
The rubber stator of the screw pump is the main vulnerable part, and it wears faster when conveying media containing particulate impurities. In the chemical industry, the average replacement cycle is only a few months, and the material backflow caused by the wear of the stator will also accelerate the wear of the screw. The vulnerable parts of the rotor pump are the mechanical seal and the bearings. The mechanical seal can operate stably under the protection of the water cooling system, and the replacement cycle of the bearings is even longer. Moreover, the replacement of components is simple, reducing the maintenance difficulty and cost. Bonve's pump, with its reliable structural design, further reduces the maintenance frequency and cost.
· Service Life and Costs
In the long run, the rotor pump, with its stable performance and low failure rate, significantly reduces the comprehensive costs of equipment procurement, maintenance, and labor. It has a long designed service life, can operate continuously and stably during the operation process, effectively reduces downtime, and improves production efficiency. In contrast, although the initial procurement cost of the screw pump is relatively low, due to factors such as frequent replacement of vulnerable parts and production losses caused by decreased efficiency, the long-term comprehensive use cost is much higher than that of the rotor pump. Bonve's rotor pump, in practical applications, brings higher economic benefits to enterprises with its long service life and low maintenance cost.
Therefore, the rotor pump, with its advanced structure, good hygienic performance, stable conveying efficiency, and low maintenance cost, is more suitable for industries with high hygienic requirements and complex working conditions; the screw pump is suitable for scenarios with low hygienic requirements and simple working conditions. When enterprises make a choice, they need to consider their own needs, the characteristics of the media, and the cost budget to achieve maximum benefits and optimal cost savings.
