Process Technology, a wet process heating and cooling manufacturer, is introducing its SmartOne line of PTC (positive temperature coefficient) electric immersion heaters at Sur/Fin 2011.
With the SmartOne technology, thermal over-temperature protectors are no longer required for safe operation, the company says, adding that its SmartOne PTC heaters will not burn out in air like traditional resistance heaters.
A PTC heater utilizes solid state ceramic heating elements as its heat source. These devices are “self-limiting” - the maximum temperature is internally limited regardless of the operating conditions. Therefore, these heaters have a built-in safety not previously available in electric immersion heaters. Traditional resistance heaters have the potential for a runaway heat condition if operated out of solution, but a PTC heater can self limit its maximum temperature regardless if operated in water, air, or surrounded by buildup.
If the temperature goes down, so does the resistance (thereby increasing power output). If the heat transfer is restricted, as would happen when i.e. operating in air, the temperature will increase (as will the resistance) resulting in reduced power output. (PTCs are used in car seat warmers or hair dryers for example – the product reaches a predetermined maximum temperature and then turns itself down.)
Common threats to heater life are buildup and scale which cause overheat situations. These conditions will not cause the SmartOne to overheat, the company says. The maximum output temperature is below the ignition point of most plastic tanks, so overheat damage is prevented if the element is operated in air or becomes covered with buildup.