To heat jet fuel in an airline delivery vessel to keep it from freezing.
Pipe thread construction, fit into the existing design, thermostat controlled and must be explosion-proof.
The potential customer had recently received a large price increase for their vendor. The customer was already using a competitor’s pipe thread equivalent of a strip heater that allowed them to get a higher KW in a shorter heater length aiding in a reasonable w/in2.
We suggested switching to a tubular element but the diameter of the customer’s equipment fitting wouldn’t allow us to fit more than one “U” bent element along with a thermowell.
Kerosene oil at 100°F can handle a watt density of 20 w/in2. In order to maintain the watt density and a short single element we suggested “J” bending the element back. This allowed us to provide a Kerosene oil at 100°F can handle a watt density of 20 w/in2 small diameter threading and a longer element bent back to keep it at a shorter length. Since the heater needed to be operated in a hazardous area we designed the elements out of 304 SST as well as the fitting. We put a NEMA 7 terminal box on the fitting and also provided a NEMA 7 indicating light that the customer would install in one of the hubs to indicate that the heater was on.