Heaters with Vertical Coils, Helical coil, Arbor Coils

Heaters with Vertical Coils

A vertical coil heater may be positioned cylindrical or in a rectangular (box-type heater). Most vertical coil heaters are bottom fired, with the stack mounted directly on top of the heater. Downdraft vertical heaters have also been used.

Heaters with Helical Coils

Helical coil heaters are cylindrical with the surface of the radiant section in the form of a coil that spirals up the wall of the heater. They do not usually have a convection section, but if one is included, the convection surface may be in the form of a flat spiral or a bank of horizontal tubes. The stack of a helical coil heater is almost always mounted directly on top of the heater.

Heaters with Arbor Coils

Heaters with arbor or wicket coils are used extensively in catalytic reforming units for preheat and reheat service and as heaters for process air or gases. These heaters have a radiant section that consists of inlet and outlet headers connected with inverted or upright L or U tubes in parallel arrangement. The convection sections consist of conventional horizontal tube coils.