ZW type sewage self-priming pump

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 Comparison Items Fluoroplastic self-priming pump Fluoroplastic centrifugal pump Self-priming ability Can handle media with gas content ≤15% It needs to be completely exhausted. When the gas content is >5%, it is easy to cavitation. Startup method No need to repeat the operation after the first filling Each start requires filling and exhaust Efficiency Lower (about 5-8% lower than centrifugal pump) Higher (n can reach more than 70%) Particle resistance Only suitable for media without solid particles Can handle media containing trace particles (≤0.1mm) Installation Requirements No foot valve required (except for special working conditions) Need to install bottom valve or vacuum water diversion device   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)