We design our heaters for optimum geometry of the combustion chamber and flux density of the helical coil. Our coil has a larger heat transfer surface area than those used by others. Coil diameter and length are sized to virtually eliminate flame imingement and provide optimum flame pattern. Pipe diameter for the coil is sized for an ideal fluid velocity of 7 to 11 feet per second.
Heatec HCM heaters use centrifugal pumps to circulate the thermal fluid. These pumps have mechanical seals. They are air-cooled, eliminating the need for water cooling.
Construction of our HCM helical coil heaters is illustrated in the drawing shown above. The heater has a steel cylindrical shell that houses a helical coil. Oversized stainless pads inside the shell support the coil, leaving an annular space between the coil and the shell. The inner surface of the shell is covered with ceramic blanket insulation that has low thermal conductivity and low heat storage. It is coated with a hardener for longer life.
A burner mounts on one end of the shell and fires through the center axis of the coil. Its flame produces radiant energy that heats the inner side of the coil without impinging on its surfaces. Hot combustion gases turn outwards at the end of the coil. They double back into the annular space between the insulation and the exterior side of the coil, heating its outer surfaces by convection. The gases travel back the full length of the coil and then pass through the exhaust stack.
The hot helical coil heats the thermal fluid as it circulates through the coil. In turn, the hot fluid heats coils in storage compartments filled with asphalt, heavy fuel, sulphur or phosphates.