1. The types and structures of screw pumps and rotor pumps are different
Screw pumps are divided into single screw pumps, twin screw pumps, and triple screw pumps, with reliable performance, high quality, and low price. A screw pump is a kind of multi-rotor pump, belonging to a positive displacement pump, which consists of two or three screws with opposite threads. The screws are installed on parallel shafts, and the liquid is pushed into the pump by the rotation of the screws. The cam pump mainly comprises three parts: a cam rotor, a shaft seal, and a gearbox. A pair of synchronously rotating transmission gears drive the cam rotor to rotate to realize the transmission of the medium, with high efficiency and long life. The rotary lobe pump is a single-rotor pump that combines the advantages of gear pumps, Roots pumps, and rotary piston pumps. A rotor with movable or rigid vanes rotates in the pump chamber, and the liquid is pumped through the cooperation of the vanes and the cam. Inhale and discharge the pump cavity to realize the delivery of flow.
2. Different application scenarios
Rotary lobe pumps are suitable for dry suction, are easy maintenance, and have good suction characteristics. They can handle liquids with temperatures ranging from -32°C to 260°C and pressure differences up to 15 bar. They are mainly used for lubricating oil service and delivery, bilge drainage, fuel loading, and other light viscosity liquid treatment.
Screw pumps are suitable for high-viscosity, high-pressure, and high-temperature occasions. They can handle liquids with temperatures ranging from -20°C to 200°C and pressures up to 120 bar. They are mainly used for liquid transportation in oil and gas, chemical, paper, food, and other industries.
Application examples of cam rotor pump and screw pump
1. Rotary lobe pumps can be used for the treatment of lubricating oil service and delivery, bilge drainage, fuel loading, and other light viscosity liquids, as well as non-lubricating liquids such as liquefied petroleum gas, ammonia, solvents, alcohol, fuel oil, Gasoline, and refrigerant, etc.
2. Screw pumps can be used for high-viscosity, high-pressure, high-temperature liquid transportation in oil and gas, chemical, paper, food, and other industries, and can also be used for spraying high-viscosity materials such as gypsum, even those containing heavy fillers, coarse particles or fibers Material.
Comparison of advantages and disadvantages of lobe rotor pump and screw pump
Benefits of rotary lobe pumps:
– Can be dry sucked, easy to maintain, and has good suction characteristics
– Can handle liquids with a wide temperature range and high differential pressure
– Can handle non-lubricating liquids, such as LPG, ammonia, solvents, alcohol, fuel oil, gasoline, refrigerants, etc.
Disadvantages of rotary lobe pumps:
– Can only be used for the treatment of light viscosity liquids, not suitable for liquids with high viscosity or containing particles or fibers
– The gap between the vane and the cam will cause the liquid to slip from the high-pressure side to the low-pressure side, reducing the volumetric efficiency
– Friction between vanes and cams creates heat and noise, increasing energy consumption and wear
Advantages of screw pumps:
– Can be used in high viscosity, high pressure, and high-temperature occasions, with high volumetric efficiency and energy efficiency
– Can be used to spray high-viscosity materials such as gypsum, even materials containing heavy fillers, coarse particles, or fibers
– No friction and wear due to no mechanical contact between the screws, smooth operation, and low noise
Disadvantages of screw pumps:
– The gas elastic device is required to discharge light gas, otherwise, it will affect the pumping speed and ultimate pressure
– Lower pumping speed and ultimate pressure for light gases (helium and hydrogen), if there is no gas elastic device
– Cannot be scaled down to pumping speeds less than 50 m³/h, below about 100 m³/h requires multi-stage roots or drum pumps
