Learn more about self-priming pumps: key performance and selection guide

This article aims to introduce the performance of self-priming pumps in more detail and under what working conditions you should choose #self-priming pumps. I hope it will be helpful to you.

1. Comparison between #fluoroplastic self-priming pump and #stainless steel self-priming pump

①. Fluoroplastic self-priming pump

Performance characteristics: Made of PTFE/PP and other materials, resistant to strong acids and alkalis (such as 98% sulfuric acid, 50% hydrofluoric acid)

Applicable working conditions: chemical waste acid treatment, electroplating liquid transportation, corrosive media in the pharmaceutical industry

Advantages: Corrosion resistance far exceeds that of metal pumps, light weight (30% lighter than stainless steel of the same model)

Disadvantages: Upper temperature limit 120℃ (stainless steel can reach 200℃), not resistant to particle wear

②. #Stainless steel self-priming pump (304/316L)

Performance characteristics: high mechanical strength (compressive capacity up to 1.6MPa), can handle media containing trace solid particles

Applicable working conditions: food processing (such as sauce transportation), seawater desalination pretreatment, environmental sewage treatment

Advantages: good structural stability, long maintenance cycle (bearing life is about 8000 hours)

Disadvantages: not resistant to chloride ion corrosion (316L should be used with caution when Cl-＞200ppm)

2. #Fluoroplastic self-priming pump vs #Fluoroplastic centrifugal pump‌

①. Fluoroplastic self-priming pump‌

Through the gas-liquid separation chamber and reflux hole design, it needs to be filled with liquid once before the first start, and then the air in the suction pipeline can be automatically discharged to form a vacuum (the self-priming height is usually 3-4m)

Typical structure: external mixing design, the impeller groove and the volute cooperate to achieve gas-liquid mixing and separation

②. #Fluoroplastic centrifugal pump‌

Relies on the centrifugal force of the impeller to transport liquid, must be completely filled with liquid and exhausted before starting, no self-priming ability

Typical structure: closed impeller + volute flow channel, high requirements for medium purity

③. Key performance comparison

④. Typical application scenarios

Preferred working conditions for fluoroplastic self-priming pumps

Intermittent operation: such as chemical tank truck unloading, electroplating liquid circulation

Large liquid level fluctuations: underground storage tank suction, emergency drainage

Preferred working conditions for fluoroplastic centrifugal pumps

Continuous and stable transportation: pickling production line, pure water circulation system

High head requirements: chemical process pressurization (head can reach more than 80m)

⑤. Selection recommendations

Select self-priming pumps: when the working conditions have frequent start and stop, pipeline gas storage risks or the installation position is higher than the liquid level

Select centrifugal pumps: for scenes that pursue high efficiency, large flow stable transportation and can ensure continuous filling

3. Stainless steel self-priming pumps vs. #Stainless steel centrifugal pump

①.Core differences:

Self-priming ability: The self-priming pump can form a 5m water column vacuum when it is first started (the centrifugal pump needs to be filled with water)

Gas-liquid mixed transmission: The self-priming pump can handle media with a gas content of 15% (the centrifugal pump is limited to 5%)

Efficiency curve: The centrifugal pump is 5-8% more efficient at the rated point, but the self-priming pump is more stable under variable conditions

Installation requirements: The centrifugal pump requires NPSH>3m, and the self-priming pump allows a negative NPSH

②.Selection suggestions:

Select a self-priming pump for frequent start-stop/liquid level fluctuations (such as unloading oil from a tanker truck)

Select a centrifugal pump for large flow and stable conditions (such as fire water supply system)