An early but ongoing popular product of St.Louis-based Watlow is celebrating its half-century mark. The Firerod, a heating element introduced in 1954, was the first swaged cartridge heater, according to

the company, which makes heaters, controllers and temperature sensors.

George Desloge, the second Desloge generation to lead Watlow, wanted a heater that would operate effectively under extreme temperatures without compromising service life. He used a technique called swaging, which reduced the cartridge heater's diameter by compacting the unit through a mechanical machine-and-die process. The space between the resistance wires and the metal sheath was reduced, and the magnesium oxide was compacted to a predetermined density.

Compaction meant the element could achieve approximately the same level of effectiveness with significantly less insulation. The result was improved dielectric strength, more efficient heat transfer, better temperature uniformity, and higher shock and vibration tolerance levels. Swaging enabled users to achieve desired process temperatures more quickly and allowed resistance wires to operate at lower temperatures, both of which helped reduce energy costs and improved heater life.

At the time, Firerod could produce several times the power per square inch compared to traditional designs, according to Watlow, allowing customers to achieve comparable watt densities using smaller heaters. The brand continues to be

used in diverse applications, including manufacturing Intel chips, perforating trash bags and packaging chicken nuggets.