Feldmeier Stainless Steel Triple Tube Heat Exchanger-12 Tubes. Thickness: 0.065 in. Inner tube: 0.87 in. diameter (inner dia.) x 247 in. L, total holding capacity: 9.6 gal. Intermediate tube: 1.37 in. diameter (inner dia.) x 238 in. L, total holding capacity: 12 gal. Outer tube: 1.86 in. diameter (inner dia.) x 222 in. L, total holding capacity: 14.5 gal. Concentrically mounted tubes. In actual process, the heating or cooling medium travels in one direction through the inner tube and through the annular space between the intermediate and outer tubes. The product flows in the opposite direction through the annular space between the inner tube and the intermediate tube. This produces counter flow action. Substantial heat exchange efficiency results from this counter flow. Frame dimensions: 200 in. L x 39 in. W x 9 in. H. Inlets/outlets: (4) 3 in. 'S' line fittings. Overall dimensions: 21 ft. L x 47 in. W x 46 in. H.