In Process Gas Coolers offered by us gas passes through tubes, the cooling length of which is subdivided into different sections. The important sections include a hot or inlet section, a medium temperature or intermediate section, and a cool discharge section. These sections carry out different process enabling the gas to cool the system fro which it is used. Primarily, the tubes are of inverted U-shape and preferably are of serpentine form where one arm of the U has portions overlapping the other arm for greater heat exchange.