WHAT IS THE DIFFERENCE BETWEEN ETFE AND PTFE?18th Aug 2014
ETFE (or Ethylene tetraflurorethylene) is a fluorine based plastic, equipped with a high melting point and an excellent chemical, electrical and high energy radiation resistance property.
PTFE (or polytetrafluroethylene) is a fluorocarbon solid. Working as a hydrophobic, neither water nor water-based substances wet PTFE. PTFE reduces friction, wear and therefore energy consumption of pumps as it has one of the lowest coefficients of friction against any solid.
Crest Pumps champion the use of both PTFE and ETFE in our Magnetic Drive and Mechanical seal Pumps.
The AM, AMX, AMXI and AMA ranges are all available in ETFE, making them extra resilient to the most arduous of corrosive applications that could break other materials and cause serious downtime to the production line.
ETFE vs PTFE
The most common materials to be used to re-enforce a pump is PTFE and ETFE polymers.
PTFE is constructed from carbon and fluorine atoms whereas ETFE is built from carbon, fluorine and hydrogen. Giving advantages to using both.
The tensile strength of ETFE can be as much as 38% greater than PTFE, meaning ETFE material can be subjected to harsher operating conditions than its counterpart. This is why most chemical pumps are supplied in ETFE as it is a stronger material for the injection moulding process they go through.
However PTFE has a coefficient of friction at one-third of ETFE making it more suitable when a high flow is needed as it helps reduce pipe friction Losses.Thermal properties of both materials are also a key differentiation… PTFE can reach a maximum temperature of 327c whereas ETFE can reach a maximum temperature of 267c.
This stage is critical when choosing the best suited pump; if the application needed to be pumped can reach anywhere near these temperatures it is best to choose PTFE as both materials get softer near their maximum temperature points.
Furthermore, PTFE has a Limiting Oxygen Index (the minimum percentage concentration of oxygen at which the polymer will burn) greater than 95% whereas ETFE is between 30-36%, meaning that PTFE should be considered in higher oxygen environments.