What medium is suitable for magnetic pumps

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This post was last edited by wx_Us4WS on 2023-2-13 09:24. 1. For pumps used to transport corrosive media, it is required that the components involved in the flow process be made of corrosion-resistant materials, such as fluoroplastic corrosion-resistant pumps. 2. For pumps used to transport flammable, explosive, toxic, or valuable fluids, it is required that the shaft seal be reliable, or that leak-free pumps be used, such as magnetically driven pumps (which have no shaft seal and rely on indirect magnetic drive). 3. For pumps used to transport media containing solid particles, it is required that the moving parts be made of wear-resistant materials; where necessary, the shaft seals should be flushed with a clean liquid. 4. Ensure that the type and performance of the selected pump meet the requirements of the plant’s process parameters such as flow rate, head, pressure, temperature, net positive suction head, and suction lift. 5. Mechanically, high reliability, low noise, and minimal vibration are required. 6. It is necessary to accurately calculate the cost associated with purchasing pumps, and it is also important to evaluate the manufacturers, ensuring that their equipment is of high quality, that they offer good after-sales service, and that spare parts are available promptly. This is something that every purchaser must take into consideration. There is a general consensus worldwide regarding the selection of magnetic materials for magnetic pumps: NdFeB materials can operate at temperatures below 150°C, while SmCo materials can function at temperatures below 250°C. For miniature pumps, aluminum ferrite can be used. Pump body materials are divided into two main categories: metallic and non-metallic. Stainless steel metal does not mean it is rust-proof against all liquids; it is primarily used with process liquids, valuable liquids, and ultra-pure liquids that are compatible with it. Non-metals are specifically developed for corrosive applications. It is further divided into 2 cases. The first is a pure plastic pump, molded thermoplastically from pure polypropylene or ethylene fluoride. The second is the lined pump, which is a popular method for lining corrosion-resistant pumps with plastic. Selection of flow-through components for magnetic pump systems in the case of special media: 1. Sulfuric acid: As one of the highly corrosive media, sulfuric acid is an important industrial material with a wide range of applications. Sulfuric acid at different concentrations and temperatures causes varying degrees of corrosion to materials. For concentrated sulfuric acid with a concentration of over 80% and a temperature below 80°C, carbon steel and cast iron exhibit good corrosion resistance; however, it is not suitable for sulfuric acid that flows at high speeds, and it cannot be used as material for pumps and valves ； Ordinary stainless steel also has limited uses in sulfuric acid media. Therefore, pump valves for transporting sulfuric acid are usually made of high-silicon cast iron or highly alloyed stainless steel. Fluoroplastics exhibit good resistance to sulfuric acid, making the use of fluorine-lined magnetic pumps a more economical option. 2. Nitric acid: Most metals are rapidly corroded and damaged by nitric acid when using magnetic pumps; stainless steel is the most widely used material resistant to nitric acid, exhibiting good corrosion resistance across all concentrations at room temperature. It is worth noting that stainless steel containing molybdenum does not have better corrosion resistance to nitric acid than ordinary stainless steel, and in some cases its resistance is even lower. For high-temperature nitric acid, titanium and titanium alloy materials are typically used. 3. Hydrochloric acid: The vast majority of metal materials are not resistant to corrosion by hydrochloric acid (including various stainless steel materials); high-molybdenum high-silicon iron can only be used in hydrochloric acid at temperatures below 50°C and concentrations of 30% or less. Unlike metal materials, the vast majority of non-metallic materials exhibit good corrosion resistance to hydrochloric acid; therefore, magnetic pumps with rubber or plastic linings are the best choice for transporting hydrochloric acid. 4. Acetic acid: It is one of the most corrosive organic acids; ordinary steel is severely corroded by acetic acid at all concentrations and temperatures. Stainless steel is an excellent material resistant to acetic acid, and 316 stainless steel containing molybdenum can also be used in high-temperature environments as well as with dilute acetic acid vapors. For demanding applications such as high-temperature, high-concentration acetic acid or environments containing other corrosive substances, high-alloy stainless steel pumps or fluoroplastic pumps can be used. 5. Bases (sodium hydroxide): Steel is widely used in sodium hydroxide solutions at temperatures below 80°C and with concentrations up to 30%. In many factories, ordinary steel is still employed for magnetic pump applications at temperatures up to 100°C and with concentrations below 75%; although corrosion increases, the cost advantage remains. Ordinary stainless steel does not have a significant advantage over cast iron in terms of corrosion resistance to alkaline solutions; it is not recommended to use stainless steel unless a small amount of iron is allowed to be present in the medium. For high-temperature alkaline solutions, titanium and titanium alloys or highly alloyed stainless steels are commonly used. The company’s standard cast-iron pumps can be used for alkaline solutions at normal temperatures and low concentrations; for special requirements, various stainless steel pumps or fluoroplastic pumps can be employed. 6. Ammonia (ammonium hydroxide): Most metals and non-metals suffer only mild corrosion in liquid ammonia and ammonium hydroxide solutions; only copper and its alloys are not suitable for use. Most of the company’s products are suitable for transporting ammonia and ammonia solutions. 7. Saltwater (seawater): Ordinary steel experiences a low rate of corrosion in sodium chloride solutions as well as in seawater and brackish water; coating protection is generally required ； Various types of stainless steel also have very low uniform corrosion rates, but local corrosion may occur due to chloride ions; therefore, 316 stainless steel is generally a better choice for magnetic pumps.