Improving Air Heater Life
Air heaters are key components in several industrial processes and identifying the element’s true temperature can be difficult. Thermocouple placement and type can dramatically effect temperature readings. The equipment and materials surrounding the thermocouple will wick heat away causing temperature changes. Don’t assume the readings are that of the heater element. The environment plays a role. That assumption is often the cause of overshoot that shortens the lifespan of the heater element component.
Understanding the heater element construction and adapting the controls to manage its lifespan is crucial. Here are some quick pointers to help develop a heating system for sustained performance.
Understand that heater element life is the direct result of the Elements Wire Temperature. Wire Temperature is the result of the Control Settings, Wire Gauge, Application Environment and Air Flow.
Lower element temperatures result in exponentially longer life of the heating element. ( see the graph below )
Warm up time is important. Just because a heater can ramp up to temperature quickly doesn’t mean the environment surrounding are warm enough to maintain the needed process temperature. Starting the production process before everything is warmed up will force the heater to run hotter than necessary and shorten it’s life. Allow the SYSTEM time to heat up at 70 to 80% of the normal operating temperature for a 5 to 10 minute period. Don’t force the heater to over work. Think of your oven at home, that’s why it has a preheat alarm. It lets you know when the ENVIRONMENT is to temperature.
The process air temperature IS NOT the element temperature. The air passing through the element coil is heated and already beginning to cool as it moves further down the process. While our TUTCO SureHeat Serpentine technology offers higher watt density than other heating coils, single length elements can have heat losses near 30% pending the distance from the element. Keeping the element as close to the process as possible, preheating the process, and proper insulation will help retain heat and manage the heater element life.