How to choose a corrosion-resistant chemical pump?

Selection criteria and principles for corrosion-resistant chemical pumps.

 

The basis for pump selection should be considered from five aspects based on the process flow, water supply and drainage requirements, namely liquid conveying capacity, device head, liquid properties, pipeline layout, and operating conditions.

 

1. Flow rate is one of the important performance data for pump selection, which is directly related to the production capacity and conveying capacity of the entire device. In the process design of the design institute, the normal, minimum, and maximum flow rates of the pump can be calculated. When selecting a pump, it is based on the maximum flow rate and takes into account the normal flow rate. When there is no maximum flow rate, 1.1 times the normal flow rate is usually taken as the maximum flow rate.

 

2. The required head of the device system is another important performance data for pump selection, and the head is generally selected by amplifying the margin by 5% -10%.

 

3. Liquid properties, including the name of the liquid medium, physical properties, chemical properties, and other properties. Physical properties include temperature c, density d, viscosity u, solid particle diameter in the medium, and gas content. This involves the head of the system, effective cavitation margin calculation, and appropriate pump type: chemical properties mainly refer to the chemical corrosiveness and toxicity of the liquid medium, which is an important basis for selecting pump materials and the type of shaft seal.

 

4. The pipeline layout conditions of the device system refer to the height of the liquid delivery, the distance from the liquid delivery direction, the lowest liquid level on the suction side, the highest liquid level on the discharge side, and other data, as well as pipeline specifications and their lengths, materials, pipe fittings specifications, quantities, etc., in order to calculate the system head and verify the cavitation margin.

 

5. There are many contents of operating conditions, such as liquid operation T saturated vapor force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, whether the ambient temperature operation is intermittent or continuous, and whether the pump position is fixed or movable.

 

 

Principles for selecting corrosion-resistant chemical pumps:

 

1. Ensure that the selected pump type and performance meet the requirements of process parameters such as device flow rate, head, pressure, temperature, cavitation margin, suction head, etc.

 

2. It must meet the requirements of the medium characteristics.

 

For pumps that transport flammable, explosive, toxic or valuable media, reliable shaft seals or leak free pumps such as magnetic drive pumps, diaphragm pumps, and shielded pumps are required; For pumps that transport corrosive media, corrosion-resistant materials are required for the convection components, such as AFB stainless steel corrosion-resistant pumps and CQF engineering plastic magnetic drive pumps.

 

For pumps conveying media containing solid particles, it is required that the convection components use wear-resistant materials, and if necessary, the shaft seal should be flushed with clean liquid.