How to choose a chemical pump?

Different environments, different media, different materials... It seems that it is not so simple to choose the right chemical pump. The wrong pump can damage the equipment at least, and cause accidents or even disasters at worst!

Today Shuangbao will introduce to you today the knowledge about type selection based on past trade experience, hoping to be of some help to us chemical workers.

Principles of chemical pump selection:
   1. Make the type and performance of the selected pump meet the requirements of process parameters such as device flow, lift, pressure, temperature, cavitation flow, and suction.
   2. Need to meet the requirements of medium characteristics.
   The requirements of medium characteristics must be met. For pumps conveying flammable, explosive, toxic or valuable media, reliable shaft seals or non-leakage pumps are required, such as magnetic drive pumps (no shaft seals, isolated magnetic indirect transmission). For pumps with corrosive media, the convection parts are required to be made of corrosion-resistant materials, such as fluoroplastic corrosion-resistant pumps. For pumps conveying media containing solid particles, the convection parts are required to be made of wear-resistant materials, and the shaft seal should be washed with clean liquid if necessary.
   3. High mechanical reliability, low noise and vibration.
   4. Consider the input cost of pump purchase comprehensively.
   The principles, internal structures, and components of some pumps are similar, and the biggest difference is reflected in the material selection, workmanship and quality of the components. Different from other products, the cost difference of pump components is very significant, and the price gap of hundreds or thousands of times is reflected in the performance and service life of the product.

 
The selection basis of chemical pumps:
   The selection basis of chemical pumps should be based on the process flow, water supply and drainage requirements, and be considered from five aspects, namely liquid delivery volume, lift, liquid properties, pipeline layout, and operating conditions.
   1. Traffic
   Flow rate is one of the important performance data of pump selection, which is directly related to the production capacity and delivery capacity of the whole device. For example, in the process design of the design institute, the three flow rates of normal, small and large pumps can be calculated. When selecting a pump, the maximum flow is taken as the basis and the normal flow is taken into consideration. When there is no large flow, usually 1.1 times the normal flow can be taken as the maximum flow.
   2. Head
   The head required by the installation system is another important performance data for pump selection. Generally, the head needs to be enlarged by 5%-10% to select the model.
   3. Liquid properties
   Liquid properties, including liquid medium name, physical properties, chemical properties and other properties, physical properties include temperature c density d, viscosity u, solid particle diameter and gas content in the medium, etc., which relate to the head of the system, effective cavitation Quantity calculation and suitable pump type: chemical properties, mainly refer to the chemical corrosion and toxicity of the liquid medium, which is an important basis for selecting pump materials and the type of shaft seal.
   4. Piping layout conditions
   The pipeline layout conditions of the device system refer to the liquid delivery height, the delivery distance, the delivery direction, some data such as the low liquid level on the suction side, the high liquid level on the discharge side, and the pipeline specifications and their length, material, pipe fitting specifications, quantity, etc. In order to carry out the calculation of the comb head and the check of NPSH.
   5. Operating conditions
   There are many operating conditions, such as liquid operation T saturated vapor pressure P, suction side pressure PS, discharge side container pressure PZ, altitude, ambient temperature whether the operation is intermittent or continuous, and whether the pump position is fixed or possible.