Sigma Thermal, Inc. products

A convection style heater offers the benefits of a direct-fired heater while eliminating some of the drawbacks associated with radiant heat transfer. Radiant heat transfer can be undesirable in certain temperature-sensitive applications as radiant heat transfer tends to be more intense and unevenly distributed around the coil surface. Sigma Thermal’s convection style direct fired heater utilizes a separate combustion chamber and flue gas recirculation to reduce combustion chamber temperatures to 1,400F, thereby minimizing the impact of radiant heat transfer to the process coil.

A radiant–convective style heater is the most well-known and commonly used style of direct-fired heater. These heaters utilize a bare tube radiant zone in combination with a bare / finned convection section. Vertical cylindrical, A-frame, and cabin style are the most common configurations. Sigma Thermal offers all types of radiant–convective heater designs including API 560 compliant systems.

Sometimes referred to as a weir bath heater, this is a slight variation of a traditional water bath heater that does not utilize a process coil. This type of heater is most commonly used as a direct fired reboiler for amine and glycol solutions. The bath vessel contains a fire-tube and a weir at the end of the fire-tube. The process fluid is circulated through the bath vessel in direct contact with the fire-tube. After the process fluid is heated, it falls over the weir where the return line sends it back to the process user.