The high-temperature concentrated sulfuric acid submerged pump

Use of materials

The design and material selection principle for the SDP-LSB pump is equal strength design. Regardless of the material chosen, it must ensure the pump operates normally for at least two years.

1. Pump impeller, shaft sleeve, bushing, and wear ring are manufactured using our proprietary C1, C2, and C3 nickel-chromium alloys.

This series of alloys exhibits excellent corrosion resistance. By incorporating varying amounts of elements such as Ni, Cr, and Mo into different components, they ensure reliable operation at temperatures ranging from 120°C to 190–220°C, with an annual corrosion rate below 0.1 mm. After heat treatment, the surface hardness reaches HRC 50, offering distinct wear resistance and corrosion resistance. Furthermore, the use of precision casting techniques (e.g., for impellers, shaft sleeves, bushings) enhances material density and strength, significantly extending the service life of these components. This makes them a suitable replacement for LEWMET alloys, thereby reducing pump production costs.

2. The pump body, pump cover, elbow, outlet pipe, and bracket are fabricated from our proprietary S-1 and S-2 acid-resistant ductile iron alloys. Through alloying and graphite spheroidization, these materials exhibit excellent strength and ductility, with tensile strengths ranging from 711 to 823 N/mm² and elongation rates of 5.8–7.4%. The annual corrosion rate in concentrated sulfuric acid is 0.26 mm. The shaft also utilizes ductile iron alloy, which, through alloying, graphite spheroidization, and heat treatment, ensures service life. 5.8–7.4%, with an annual corrosion rate of 0.26 mm in concentrated sulfuric acid. The shaft, also made of ductile iron alloy, undergoes alloying, graphite spheroidization, and heat treatment to ensure a service life exceeding two years. The flow-through components of the fumaric acid pump utilize 304 stainless steel, while the FRS acid pump employs corresponding materials such as 310SS and 329SS.

3. Other: Packing seals utilize oil-impregnated graphite fiber or filled PTFE fiber packing. Sealing rings employ fluororubber material. Gaskets are made of polytetrafluoroethylene (PTFE). These materials fully ensure leak-free operation under normal conditions. Additionally, for pump startup, we employ flexible serpentine spring couplings with low alignment requirements and compensating properties. For high-flow pumps, we utilize highly flexible diaphragm couplings.