What are the main factors affecting the volumetric efficiency of a G-type horizontal single-screw pump?

2025-11-11 15:49:47

The volumetric efficiency of a G-type horizontal single-screw pump is influenced by several key factors. Below are some key factors and their corresponding explanations:

Structural parameters: The structural parameters of a screw pump, such as the rotor's eccentricity, diameter, lead, and number of stages, have a direct impact on volumetric efficiency. These parameters must be maintained in a certain ratio to ensure high pump efficiency and long-term stable operation. For example, a larger eccentricity and a smaller rotor diameter may help improve volumetric efficiency, but the specific ratio needs to be determined based on the actual application.

Operating parameters: Operating parameters primarily refer to the rotor's rotational speed. Once the structural parameters are determined, the displacement is directly proportional to the rotational speed. Therefore, rotational speed is one of the key factors affecting volumetric efficiency. However, excessively high rotational speeds may increase stator and rotor wear, which in turn reduces volumetric efficiency. Therefore, it is necessary to find an appropriate speed range to balance displacement and wear.

Low submergence: When a screw pump operates at low submergence, insufficient pressure differential prevents the liquid from filling the rotor cavity, resulting in a decrease in volumetric efficiency. Especially when the lifting height is increased to its limit, the pump may not function properly or even damage the stator due to overheating.

Seal Clearance: The size of the seal clearance has a significant impact on volumetric efficiency. Maintaining clearances between the tooth sides, tooth tops, and end faces within the specified range, especially the end face clearance, helps improve volumetric efficiency. Excessive clearances may increase leakage, thereby reducing volumetric efficiency.

Discharge and Suction Pressure: Changes in discharge and suction pressure also affect volumetric efficiency. Excessively high discharge pressure or excessively low suction pressure can lead to a decrease in volumetric efficiency.

Oil Temperature and Viscosity: The oil temperature and viscosity also affect the volumetric efficiency of the screw pump. Excessively high temperatures may cause the stator rubber to age, while excessive viscosity may increase pump resistance, thereby reducing volumetric efficiency.

Speed Control: The speed should be controlled within a reasonable range, generally recommended between 1000 and 1500 rpm. Excessively high speeds may increase wear, while excessively low speeds may reduce displacement. To improve the volumetric efficiency of a G-type horizontal single-screw pump, the following measures can be taken:

Maintain the seal gap within the specified range and regularly inspect and adjust the gap.

Maintain proper shaft seal operation and promptly replace worn shaft seal components.

Prevent overpressure operation and ensure the pump operates within the rated pressure.

Control the speed within a reasonable range and select an appropriate speed based on the media properties and pump design requirements.

In actual applications, it is necessary to comprehensively consider the above factors and make adjustments and optimizations based on the specific situation to ensure the efficient and stable operation of the G-type horizontal single-screw pump.