1. Selection principle of the pump
In the selection of the centrifugal pump model, the correct determination of the centrifugal pump material is to ensure the safe operation of the centrifugal pump and prolong the service life of the pump an important factor.The choice of material should consider the influence of various factors comprehensively from many aspects, so as to select the appropriate material.
(1) the nature of the pump transport medium and pump operating conditions, such as temperature, pressure, corrosion, viscosity, whether there are solid particles.In addition, also have to consider whether there are other special circumstances, such as medicine, food industry requirements of the transport medium is particularly clean, prevent metal ion pollution, transport containing solid particle medium pump requirements of good wear resistance.
(2) The mechanical properties of the material should be suitable for the requirements of the pump.Reflect the mechanical properties of materials many indicators, the pump used by the material, mainly considering the strength of the material, steel degree, hardness, plasticity, impact toughness and fatigue performance.
(3) The material processing performance and pump manufacturing and installation maintenance has a direct relationship.Centrifugal pump impeller, shell, balance plate and other most parts are cast by metal materials, and then mechanical processing, some parts even heat treatment.
The quality of the material processing technology also directly affects the use of materials and pump costs.
(4) Corrosion resistance is the pump material selection can not be ignored important issues.For petrochemical industry, the corrosion resistance of pump is particularly important.
2. Selection of materials for commonly used corrosion resistant pumps
Acid, alkali and other corrosive liquid materials are often encountered in petrochemical production.Centrifugal pumps used to transport such materials are collectively referred to as corrosion resistant centrifugal pumps. The models of these pumps are represented by F. Their working principle is similar to that of centrifugal clean water pumps, and their corrosion resistance is mainly determined by the properties of materials used to manufacture such pumps.
The reason why most anticorrosive pumps can be anticorrosive mainly depends on the material of the flow parts of the pump, for anticorrosive pumps, according to the different transmission medium, choose the material of the flow parts of the pump.For example, 1Cr18Ni9Ti can be used for low concentration nitric acid and other oxidizing acid, alkali liquor and weak corrosive medium at room temperature: 0Cr18Ni12Mo2Ti is suitable for conveying high concentration nitric acid at room temperature, and also for conveying sulfuric acid, organic acid and other reducing medium: gray cast iron HT200 is suitable for concentrated sulfuric acid;Plastic has a wide range of application, such as ptfe and fep with reasonable formula, mold, processing a variety of materials, corrosion resistant plastic pump has strong corrosion resistance, and has high mechanical strength, not aging, and the advantages of no toxin decomposition, is an ideal equipment to transport all kinds of strong, weak acid, including ptfe is one of the good corrosion resistant material, basically can be resistant to any corrosion of acid, alkali medium, is called the king of plastic.Ceramics, enamel, glass and so on are also used in some specific occasions to manufacture corrosion - resistant pump over - current components.