PTFE hoses and metal hoses differ in their fluid-carrying material, construction and operating characteristics. Selection should be based on the needs of the system.
Material and construction
A PTFE hose has a polymer tube made from polytetrafluoroethylene. The material is valued for its chemical resistance and dielectric properties. A metallic outer braid may reinforce the tube without changing the material in contact with the fluid.
A metal hose uses a metallic fluid-carrying element, typically made from an alloy selected for the service. The original article discusses stainless steel and titanium. Alloy selection is important for corrosion resistance and the operating environment.
Flexibility and chemical compatibility
PTFE hoses can accommodate complex routing when the selected construction and bend radius permit it. Metal hose flexibility also depends on its construction; one hose type should not be assumed to be more flexible in every application.
PTFE offers compatibility with many chemicals. Metal hose compatibility depends on the alloy and the medium. Both types require an assessment of pressure, temperature, corrosion or chemical attack, mechanical loading and inspection needs.
Smooth-bore and convoluted PTFE
PTFE hoses may have a smooth or convoluted tube. Convoluted designs can offer greater flexibility for suitable routing and movement requirements.
Smooth-bore designs provide a smooth fluid path and can be useful where flow resistance and cleaning requirements are important. The final choice depends on the fluid, installation geometry and operating conditions.
Choosing an assembly
Cost varies with dimensions, construction and performance requirements. Neither material alone establishes a pressure rating or service life.
Provide the operating requirements and connection details so that the appropriate tube, reinforcement and fittings can be selected as a complete assembly.