This is how Tutco SureHeat industrial air heaters are affected by process changes, like increasing your air temperature setting:
- Increasing air pressure (psi) decreases airflow (ACFM).
- Increasing the temperature setting increases the airflow (ACFM =actual cubic feet per minute). Increasing the temperature, expands the gas, and it gets bigger, so you get more volume.
- Back pressure curves for Serpentine heaters are done at 60 deg F and 1 atmosphere of pressure. You need at least enough air pressure to overcome the back pressure generated by the air flow/temperature combination you are using for your process.
- If you have the lowest airflow and a lot of air pressure, then you can actually starve the heater for airflow.
- Two-stage heaters have the finer 18ga wire at the inlet, which has less resistance. This speeds up the heating in that section and allows it to achieve a higher peak temperature by the time it gets to the outlet, where the thicker 16ga wire can handle 1500F.
- For two-stage heaters, the air is naturally colder at the inlet, and it gets hotter as it travels down the heater coil to the exit. The initial reduced resistance at the inlet due to the finer wire allows the air to travel the same distance but get to a higher temperature.
- For two-stage heaters, if you made the whole heater using the thicker, lower gage wire (vs. the 18ga used), then it wouldn’t speed up the energizing rate, so you would only get to 1400F by the time the air reached the outlet.
- A smaller ID airline decreases air pressure, and a larger ID airline increases air pressure.
- These are some examples of how air pressure, air temperature, and airflow are all interdependent with a Max heater:
If you start off with 100cfm and are going from 1C to 147C with 87psi, then airflow at the exit of 3 heating tubes would be 6.88cfm per tube or only 20cfm total.
If you start off with 100cfm and are going from 1C to 147C with 50psi, then airflow at the exit of 3 heating tubes would be 10.81cfm per tube or only 32.44cfm total.
if you start off with 100cfm and are going from 1C to 300C with 87psi, then airflow at the exit of 3 heating tubes would be 9.37cfm per tube or only 28.1cfm total.
https://jobcosupply.com/improving-the-sylvania-air-heater-element-life/
https://jobcosupply.com/sylvania-air-heater-failures-due-to-voltage-overshoot-or-zero-airflow/
