The following points should be paid attention to the key considerations in the selection of chemical pumps.
1. The process flow of the pump. According to the essentials of the process, reasonably determine the basic parameters such as the flow rate and head of the pump. Taking into account the normal wear of the pump and the change of the speed, the head may decrease. Therefore, the head of the water pump should be selected with a margin of 2% to 5%. Can not exceed 10%, the basic principle is to ensure that the pump runs within the normal range. In addition, the information of the pump inlet status can be obtained through the process, which can be used for calculating the cavitation margin of the device.
2. The corrosiveness of the medium and the choice of materials. Due to the wide variety of chemical media with different properties, especially corrosiveness, concentration, volatility, vaporization pressure, viscosity, density and other characteristics, it is necessary to be careful in the selection of materials. The performance of the pump is closely related to the selection of materials. Not only metal materials, but also the interaction between non-metal materials and the medium.
3. The temperature of the medium. Temperature has a significant impact on the structural selection of chemical pumps. For example, the support method of the pump body and the design of the cooling (or heat preservation) system are closely related to the temperature of the conveyed medium.
4. Selection of main shaft seal and auxiliary system. Unit failures caused by the main shaft seal account for a high proportion of all failures, and can reach more than 30% to 40% in some cases. Therefore, the choice of spindle seal is very important. In addition to the physical and chemical properties of the medium, the pressure of the sealed cavity and the temperature of the medium in the sealed cavity should be understood when selecting the model.