The shell-and-tube heat exchanger consists of shell, heat transfer tube, pipe plate, baffle plate and pipe box and other components. The shell is cylindrical, with internal tube bundles, and the ends of the bundles are fixed on the tube plate. Hot and cold heat transfer of two fluids, one in the tube flow, called the tube fluid, and another in the flow outside the tube, called the shell fluid. In order to improve the heat transfer coefficient of external fluids, several baffles are usually installed in the shell. The baffle can increase the velocity of the shell fluid, forcing the fluid to cross the tube in many times, and increase the turbulent degree of the fluid. The heat exchanger can be arranged on the tubesheet by equilateral or square. The equilateral arrangement is compact, the fluid turbulence degree is high, the heat transfer coefficient is large, and the square arrangement is convenient for cleaning the pipe, and is suitable for the easily scaling fluid.
The fluid is called a tube at a time by each tube bundle; The simplest single shell-tube heat exchanger, referred to as type 1-1 heat exchanger, is shown. In order to increase the fluid velocity in the tube, the clapboard can be arranged in the pipe box of both ends, and all the tubes are divided into several groups. This means that the fluid travels through only part of the tube at a time, so it is called a multiple-tube process. Similarly, in order to improve the external flow velocity, can also be installed in the shell longitudinal baffle, forcing the fluid through the shell space, known as the multi-shell process. Multi-tube and multi-shell can be used together.