Fluoropolymer (PTFE) heater, or more commonly known as Teflon heater, are compatible with virtually every chemistry and are available in sizes up to 27kW. PTFE heaters are manufactured to heat corrosive liquid solutions, which normally used in metal finishing tanks. They are specifically designed for these process technology and only heating the part that is to be continually immersed. This plastic sheath enables the heaters to resist flow of heat and the aggressive chemical attack of the bath.
Exposing it out of solution will have a failing condition on the heater. Therefore, it is recommended to have thermal fuses or liquid level probes using alongside with the heater. While thermal fuses serve as an over-heating protection, liquid level probes monitors the solution and turn the heater off prior to exposing it to open air.
Immersion heaters with PTFE coating are usually rated with lower watt density per square inch, therefore more heating elements are needed to attain the wattage output of a similar stainless steel or titanium sheathed heater.
It doesn’t matter what chemical solution you put our PTFE heaters in, as long as it is less than 100°C, and has a pH of 0 to 13. PTFE heaters are normally designed with at least 2” “no liquid zone” or cold zone, from the bottom of the junction box. Having the chemical solution closer to the top generates more steam and harmful vapours, which eventually jeopardize the heater lifespan.