Advantages:
Good heat preservation performance: The pump body is equipped with a hollow interlayer, through which heat transfer oil, steam, hot water, etc. can be introduced to heat, preserve the temperature of and cool the transported liquid and the pump itself. It can effectively prevent media that are prone to solidifying at room temperature, such as asphalt, from solidifying and ensure good fluidity during the transportation process. It is especially suitable for outdoor installation in extremely cold regions and occasions where the medium needs to be kept warm during the technological process. The temperature of the medium can reach 250 °C, and the viscosity is 5 - 1500 cst.
Wide range of transported media: It is suitable for transporting non-corrosive media that do not contain solid particles and have solidifying properties at room temperature, such as asphalt, paraffin wax, rosin, heavy oil, resin and liquids with similar properties. The temperature is not higher than 300 °C.
Stable working performance: It has a simple structure, mainly composed of components like screws and pump casings, without complicated valves and transmission devices. It operates reliably with a low probability of malfunction. It transports media by utilizing the screw meshing principle. There is no pulsation or agitation during the operation process, and the pressure pulsation is small. It can provide a stable pressure for the system, making the entire transportation system operate more smoothly and reducing the impact on pipelines and other equipment.
High efficiency and energy saving: Under the same requirements for flow rate and pressure, compared with other types of pumps, this pump has a smaller volume, can save installation space, and is allowed to operate at a high rotational speed. To a certain extent, it improves the transportation efficiency and can meet the demand for large-flow transportation.
Low noise: It generates relatively low noise during operation and usually does not cause obvious noise pollution to the working environment and operators, which is beneficial for improving the working environment.
Good sealing performance: Mechanical seals are adopted. According to different media, different materials can be selected for the friction parts of the mechanical seals. For high-viscosity media, cemented carbide materials with good mechanical properties are selected, which can effectively prevent media leakage and meet the sealing performance requirements under high temperatures.
Disadvantages:
High requirement for medium cleanliness: The clearance between the screw and the pump casing is relatively small. If the medium contains excessive impurities, particles or fibers, it is easy to cause wear on the screw and the pump casing, affecting the normal operation and service life of the pump. Therefore, it is necessary to install filtering devices such as filters at the inlet of the pump.
Not suitable for transporting corrosive media: It is generally made of cast steel and has poor tolerance for strongly corrosive media. If corrosive liquids are transported, it may lead to corrosion damage to components such as the pump body and the screw, and special materials need to be selected or anti-corrosion treatments need to be carried out.
High requirements for machining and assembly precision: The machining and assembly precision of the screw rotor is the key to affecting the volumetric efficiency and service life of the screw pump. If the machining and assembly precision is insufficient, it may lead to problems such as poor screw meshing, excessive or insufficient clearance, etc., thus affecting the performance and service life of the pump.
Axial force exists: During the operation process, the screw will be subjected to a certain axial force. Effective axial force balancing measures need to be taken. Otherwise, it may lead to problems such as increased wear of the screw and increased bearing load, affecting the reliability and service life of the pump.
High maintenance cost: Once key components of the screw pump, such as the screw and the pump casing, are worn or damaged, the maintenance cost is relatively high. Because these components have high requirements for machining precision, professional technicians and equipment are needed for installation and debugging during replacement.
