This detailed technical diagram illustrates a U-tube shell and tube heat exchanger. The exchanger features two key fluid flows: a hot fluid on the tube side and a cold fluid on the shell side. The hot fluid enters through the tube-side inlet, passes through fixed tubes secured by a tubesheet, in a two-pass flow, and exits via the tube-side outlet. Meanwhile, cooling water (cold fluid) flows in a single pass on the shell side, entering at the shell-side inlet, passing around the U-shaped tubes and through tube baffles, and exiting at the shell-side outlet. Important components such as the front header (bonnet), pass partition plate, mounting saddles, and tube baffles are labeled, providing clear insight into the exchanger’s construction and fluid flow paths.