How to choose a rotor pump

The basic requirements for a quality-ridden rotor pump unit are performance and life. Performance is the parameters of the rotor pump: head, flow and efficiency. Lifetime is the total number of hours of operation before one or more parts must be replaced while maintaining permissible performance. It is mainly to resist corrosion in the structural materials under actual operating conditions. Erosion or a combination of both.

Factors to consider when selecting materials for the rotor pump process components are: user experience, expected pump life (eg, for short-term or long-term use), intermittent or continuous use, and conditions for pumping hazardous or noxious liquids or liquids. The corrosiveness of a liquid varies depending on one or more of the following conditions: temperature, concentration. Purity, speed. Mixed solids and gases. Stainless steel usually means that the addition of iron-based corrosion-resistant alloy elements containing 12% to 30% chromium can affect and change the alloy structure and properties. According to the different carbon content, 18% chromium stainless steel can be divided into three categories. That is, less than 0.08% carbon ferritic steel, 0.08% to 0.22% carbon austenite-ferrite and more than 0.22% carbon austenitic steel.

Considerations for selecting materials:

1) The corrosiveness of the medium: The material has a certain range of corrosion resistance to the medium.

2) Electrochemical corrosion; the same metal material is preferably used in the entire flow path of the rotor pump.

3) Medium temperature: The material is brittle at very low temperatures. Creep occurs at high temperatures; a material can withstand the corrosion of a medium at room temperature. However, it is not necessarily resistant to high temperature corrosion of the medium; so the material properties should meet the requirements of the temperature of the medium being transported.

4) Economical: Different materials, their prices and machining performance are also different, so at the same time to meet the corrosion of several materials. Under the requirements of temperature, materials with relatively cheap prices and good machining performance should be selected.

5) Abrasion of solid particles: When the medium contains abrasive solid particles, wear-resistant materials should be used.

6) Occlusality between materials; for parts with relative motion, such as shafts and bushings. The bolts and nuts, the impeller seal ring and the rotor pump body seal ring, etc., in the choice of materials should make the hardness of the parts of the material somewhat different, otherwise easy to bite in the loading and unloading and operation of synthetic scratches.

7) The temperature of the same part: When the temperature difference between the same part is large when working, such as when the pump cover is cooled during the delivery of high temperature liquid, the temperature expansion of the contact between the pump cover and the medium is large, the temperature is low and the expansion temperature is low at the contact with the cooling water. , Such parts should use good plastic material, so as to avoid cracks caused by different expansion during the movement.

8) Parts that need to be welded: The parts that need to be repaired in the process of casting, processing and use should be made of materials with good weldability. For example, the weldability of low carbon steel is better than that of high carbon steel 9) High lift: Head Very high rotor pumps have high liquid flow rates, and the flow-through components should be made of high-strength steel that is resistant to erosion and cavitation, such as precipitation hardened stainless steel.