Aluminum cast heater type DBH
DIRAC has developed and delivered a cast heater suitable for heating up a N2 gas flow.
The cast heater is in the first place developed to heat up seal gas at high pressures and low flow rates.
The cast heater is of an indirect heating type and is built up with a helix coil provided with an insert of electric tubular heating elements. Together they would be casted in aluminium.
The heat transfer from element to aluminium and from aluminium to the gas is very good.
A good design is based on a low temperature difference between the aluminium casting and the required gas outlet temperature.
Due to this no overheating can occur when gas flow fluctuates.
Gas outlet temperature would vary if flow rate fluctuates however the gas outlet temperature would never be higher than the aluminium cast temperature.
A precise gas outlet temperature is only possible by a constant flow rate.
In most of the cases pressure drop is not an issue except for low pressures <10 bar and relative high flow rates of approximately 1500 kg/h. A traditional way of heating up with a so-called in-line heater type can give problems when flow rates are fluctuated. The heater can be shut down by the master cut-out protection when element sheath temperature would rise above the set point of the protection.