What is the main advantage of a screw pump rather than an external gear pump?

Screw pumps have a strong ability to transport abrasive fluids. Gear pumps are another option, both offering the advantage of a small footprint. However, gear pumps produce significant vibrations that spread through the pipeline, causing pipeline and infrastructure vibrations. Vibration damping devices are almost always installed together with gear pumps. Their failure, jamming, inaccurate positioning, etc. can cause problems in the entire system. However, screw pumps are vibration-free and operate smoothly and quietly.


Characteristics of screw pumps and gear pumps


Screw pump

1. Screw pumps have better suction capabilities and therefore work better in longer pipelines, higher viscosity oils, and when air is present in the fluid.

2. The screw element inside the pump has a smaller diameter than the gear (for the same capacity), creating less turbulence in the fluid, resulting in smoother pumping.

3. Screw pumps can work at higher motor speeds (3000-3500 RPM).

4. The design of the screw pump has better mechanical efficiency because it uses less power at the same capacity compared to the gear pump, thus saving energy costs.

5. The screw pump runs softer, with less pulsation, less noise, and less vibration, which means a longer service life.

6. Screw pumps usually have a smaller footprint, so they are better when space is an issue.

7. Internal components such as screws generally need to be replaced at the same time to ensure efficient operation, and the maintenance cost is quite high.


Gear pump

1. The suction capacity of a gear pump is usually smaller than that of an equivalent screw pump, so it is less efficient when suction is difficult.

2. The gear needs a larger diameter to meet the required capacity, thus producing more pulsations in the fluid discharge.

3. Due to the large gear, the rotation speed is limited. If you increase the RPM, the pump will lose suction.

4. The motor in a gear pump uses higher power for the same capacity as a screw pump, resulting in increased energy costs and the need for a larger motor.

5. Gear pumps are noisier, have greater turbulence, and cause the pump and piping system to experience more vibration, thereby reducing operating life.

6. Since they usually have a larger footprint, they are not suitable for installations with limited space.

7. Internal components are generally less expensive than those in progressive cavity pumps, but because bushings and bearings are in the pumped fluid, they are more susceptible to wear.


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