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The Difference between Roots Pump And Screw Pump

Views: 158     Author: Site Editor     Publish Time: 2023-12-21      Origin: Site


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Roots pump and screw pump are both positive displacement pumps, but they have some differences in structure and working principle.

Structural differences:

The Roots pump consists of two rotating impellers that mesh with each other, with several wedge-shaped plates on each impeller. Two impellers are installed inside the pump casing through the stator and maintain minimal clearance.

Roots Pump

Roots Pump

A screw pump consists of one or more screws and a rotor, with the screws located inside the rotor and engaged with it. A fixed gap is formed between the screw and the rotor.

screw pump

Screw Pump

Differences in working principles:

When the rotor of the Roots pump rotates, the wedge-shaped plate sucks the liquid into the pump casing from the inlet, and then compresses it along the outer annular track before being discharged.

When the rotor of the screw pump rotates, the screw gradually compresses the liquid from the inlet along the screw chamber and finally discharges it.

Applicable liquid differences:

Roots pump is suitable for conveying and treating viscous liquids such as wastewater, colloids, oils, etc.

Screw pumps are suitable for conveying and processing liquids with high viscosity, such as petroleum, petroleum oils, and high viscosity chemicals.

Efficiency difference:

The efficiency of Roots pump is different from that of LC Roots pump and screw pump, which have some obvious differences.

Structural difference: Roots pumps are composed of two rotors that mesh with each other, and a sealing chamber is formed between the wedge-shaped plate on the rotor and the casing. A screw pump consists of a screw rotor and a fixed threaded housing, with liquid forming a sealing chamber between the two.

Working principle: The Roots pump pumps liquid from the suction end to the discharge end through the rotation between the rotors and the movement of the wedge plate, and the liquid is carried and transmitted between the rotors. A screw pump pumps liquid by rotating the screw and changing the indoor volume, pushing the liquid from the suction end to the discharge end.

Liquid processing capacity: Roots pump is suitable for processing liquids with high viscosity, such as oils, colloids, sludge, etc; Screw pumps are more commonly used to handle low viscosity liquids such as water, petroleum, etc.

Pressure range: The working pressure of Roots pumps is generally low, usually within the range of 1-3 bar; Screw pumps can withstand higher working pressures, typically reaching 10-30 bar.

Efficiency and noise: Due to the relatively less liquid passing through mechanical contact, Roots pumps have higher efficiency and lower noise. Screw pumps, on the other hand, have more mechanical contact during liquid transportation, resulting in lower efficiency and potentially producing higher levels of noise.

Overall, Roots pumps are suitable for handling high viscosity liquids with relatively low working pressure; Screw pumps are suitable for processing low viscosity liquids and can withstand high working pressures. When choosing to use, it is necessary to decide which pump type to use based on the specific liquid properties and working requirements.


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