We were approached by a chemical processing customer to encapsulate free-issue conical springs. We recommended a thin wall PTFE sleeve coating and through careful engineering, ensured the sleeving didn't affect the performance of the conical spring.

The project: Encapsulating conical springs in PTFE

We encapsulated free-issue conical springs in thin wall PTFE sleeving. Used in an aggressive chemical application, the Hastelloy wires were encapsulated in a tube with a 0.15mm wall thickness, then sealed at both ends. We spark tested the encapsulated springs to ensure the integrity of the seal.

The application required the springs to lay flat when compressed. We recommended a thin wall sleeve coating to encapsulate the component, as a spray coating wouldn’t provide a robust enough protection against chemicals and would impact the flexibility of the spring. Given the small diameter of the wires and the complex profile of the spring, it proved challenging to apply the sleeve coating.

For this chemical processing application, PTFE was chosen for its chemical resistance, mechanical properties and temperature tolerance. PTFE is highly chemically resistant. Chemicals that the material is resistant to include, but are not limited to, acetone, formic acid, hydrofluoric acid, nitric acid, diesel oil, phosphoric acid and sulphur dioxide.

PTFE also has fantastic non-stick qualities – this is an added benefit in the chemical processing industry as it prevents a build-up of microbes and bacteria. Finally, the fluoroplastic is ideal for use in very high and very low working temperatures, and can withstand temperatures from -200°C up to +260°C.

Encapsulating fluoroplastics

Encapsulating components with fluoroplastics provides you with a high temperature, chemically inert and non-stick coating. FEP, PFA and PTFE are some of the most inert materials known to man, and they also have a very high temperature resistance. They are ideal materials for the protection of components in applications where highly corrosive or solvent conditions exist.

Using combinations of custom manufacturing techniques in conjunction with thermoforming processes, a coating can be applied on almost any item in FEP, PFA and PTFE. Your components can be encapsulated in heat shrink as well as non-heat shrink tubing. Once applied, all our fluoropolymer coatings are fully inspected and spark tested to ensure the integrity of the seal.

Here at Adtech, we are specialists in delivering innovative fluoroplastic solutions for your technical applications. We understand that every customer’s application is different, so our knowledgeable customer service and R&D teams are on hand to discuss your project.

Get in touch today to ask for more information or to discuss your requirements:

t: +44 (0) 1285 762000

e: sales@adtech.co.uk

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