PT&P custom-designed “mini” big ton spring supports to support a large centrifugal fan at a chemical refinery in Texas. They are designed to support a total weight of 33,000 lb. within a maximum space envelope of 4″ wide x 16″ long x 8″ tall. As a result, these mini big-tons were fabricated using coils that could be placed in parallel within their respective frames. Four of the units were comprised of four inner coils nested inside four outer coils to produce an operating load of 4,478 lb. and an overall spring rate of 2,740 lb./in. The smaller load capacity units were configured with four individual coils in parallel with an operating load of 3,735 lb. and a spring rate of 2,300 lb./in. The frame, load flange, and all internal components were fabricated from carbon steel. The spring coils were fabricated from ASTM A-5160 spring steel. All supports were tested through their total working range to confirm load capacity and functionality.
