Plastic Chemical Pumps: Handling Corrosive and Aggressive Fluids

Chemical process pumps are required to handle some of the most aggressive and corrosive fluids used in industry. Selecting the right pump materials is therefore critical to achieving safe, reliable operation and a long service life.

For transferring corrosive and aggressive fluids, plastic can be an effective alternative to metallic pump materials. Plastic pumps can either be injection moulded or plastic-lined, providing excellent chemical resistance for demanding industrial environments.

Are Plastic Pumps Inferior to Steel Pumps?

Not at all. Plastic may not immediately seem like the obvious material choice for an industrial chemical pump, but when correctly selected for the chemical, temperature and operating conditions, it provides excellent resistance to aggressive and corrosive fluids.

CDR Pumps has been manufacturing plastic chemical pumps since the 1970s. In 1978, the first plastic magnetic drive pump was developed at our manufacturing facility in Italy. The TMN-BS was produced in polypropylene, PVDF and ETFE, paving the way for today’s ranges including the STN, ETN and UTN magnetic drive pumps.

The chemical resistance of many plastics is excellent. Polypropylene, PVDF, ETFE and PFA offer resistance to a wide range of aggressive chemicals, making them well suited to demanding chemical processing applications.

Plastic pumps can also provide a cost-effective solution for corrosive chemical duties, with material options suitable for operating temperatures of up to 180°C.

CDR plastic pumps are manufactured from, or lined with, carefully selected virgin materials rather than glass-fibre-reinforced plastics. For plastic-lined pumps, a specialised transfer moulding process is used in which the lining becomes mechanically keyed to the metal structure of the pump. This ‘lining-locking’ mechanism securely retains the lining within the pump casing and prevents movement caused by the centrifugal forces during operation.

Plastic-Lined Pumps for Hydrochloric Acid

An example of plastic pump technology in practice involves a chemical manufacturer looking for a safe and reliable solution for unloading 36% hydrochloric acid.

Hydrochloric acid is highly corrosive and can be harmful through direct contact or exposure to its fumes, making effective fluid and vapour containment an important consideration when selecting pumping equipment.

Four UTN-B PFA-lined magnetic drive pumps were selected, combining a chemically resistant PFA lining with a robust ductile iron outer casing. The seal-less magnetic drive design removed the need for a dynamic mechanical seal, eliminating a potential leakage point when handling the corrosive fluid.

The fluoropolymer PFA (perfluoroalkoxy) was selected as the pump lining material due to its excellent chemical resistance. While sharing many of the chemical-resistant properties of PTFE, PFA offers an ultra-smooth, low-adhesion surface well suited to handling acids. It also retains its reliability at elevated temperatures and offers excellent long-term durability, making it a strong material choice for demanding chemical processing applications.

Read the full hydrochloric acid pump case study to find out more about the application and solution.

Applications for Plastic-Lined Pumps

Plastic-lined CDR pumps are used across a wide range of industrial applications where chemical resistance and reliable fluid handling are crucial.

Typical sectors include:

• Semiconductor manufacturing – where chemical compatibility and reliable fluid containment are critical
• Water and wastewater treatment – dosing and transferring chemicals used throughout treatment processes
• Pharmaceutical manufacturing – where purity, precision and reliable fluid handling are essential

Selecting the Right Plastic Pump

Plastic and plastic-lined pumps can provide an effective solution for handling a wide range of corrosive and aggressive chemicals, but selecting the correct material is critical.

Chemical compatibility depends on factors including the fluid being handled, its concentration and temperature, as well as the wider operating conditions. Selecting the right combination of pump technology and wetted materials is therefore key to achieving safe, reliable operation and a long service life.

To find out more about the plastic pump and lining options available, or discuss the most suitable materials for your application, contact the CDR Pumps team on 01933 674777 or at sales@cdrpumps.co.uk

View our range of non-metallic magnetic drive and mechanical seal centrifugal pumps.