Method for the construction of a baffled heat exchanger

#The present invention relates generally to heat exchangers and to methods of heat exchanger construction.

#Heat transfer is an important part of any process. As is well known, an indirect transfer of heat from one medium to another is usually accomplished by the use of heat exchangers of which there are many types. For example, there are double pipe, shell and tube, plate heat exchangers and others. Indeed the art of heat exchanger design is developed to a very high degree. However, there is still room for improvement in a number of areas, such as reducing pressure drop, increasing overall heat transfer coefficients, reducing fouling, and in heat exchangers utilizing a tube bundle, such as the shell and tube heat exchangers, improving the tube support and ease of assembly. In many instances, the tubes in a shell and tube heat exchanger prematurely fail because the tubes vibrate or rub against one another or other parts of the heat exchanger, such as for example, a baffle or the shell.

#The art has heretofore recognized the need for tube support. Plate type baffles have been used in heat exchangers for many years. Such baffles provide support for the tubes at least to some degree. The double segmental plate-baffle heat exchanger is well known to those skilled in the art, and although heat exchangers using plate-type baffles were a relatively early development in heat exchanger design, such exchangers are still widely used today. In most plate-type baffle heat exchangers the passages in the plate baffles through which the tubes pass are slightly larger in diameter than the outside diameter of the tubes in order to facilitate construction of the exchanger, and, as a result, vibration of the tubes can and does often occur, which frequently results in premature tube failure.

#Other objects, aspects and advantages of the present invention will be apparent to those skilled in the art upon reference to the present specification and accompanying drawings in which:

#FIG. 1 is a side elevation view of a heat exchanger employing a tube bundle constructed in accordance with the present invention with portions of the shell broken away to more clearly illustrate the internal construction thereof;

#FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1;

#Referring now to the drawings, and to FIG. 1 in particular, a single pass shell and tube heat exchanger, generally designated by the reference character 10, is illustrated therein. The heat exchanger 10 comprises a shell 12 and a tube bundle 14 positioned therein.

#The tube bundle 14 includes a pair of tube sheets 16 and 18 having apertures formed therein through which the opposite ends of a plurality of tubes 20 extend. The opposite ends of the tubes are secured to the respective tube sheets to provide support for the plurality of parallel aligned tubes 20. A pair of baffles 22 and a second pair of baffles 24 are positioned alternately along the longitudinal axes of the parallel tubes 20 in spaced relation and provide support for the tubes intermediate the tube sheets 16 and 18. While the baffles 22 and 24 are shown lying in a plane normal to the longitudinal axis of the tubes 20 of the tube bundle 14, it is possible to use baffles which are not in planes perpendicular or normal to the longitudinal axis of the tube bundle, however, baffles lying in perpendicular or normal planes as shown are more easily and economically constructed and are thus preferred.

#Nozzles 26 and 28 communicate with the respective opposite ends of the tube side of the heat exchanger 10 providing means for passing a first fluid through the tubes. Nozzles 30 and 32 communicate with the respective ends of the shell side of the heat exchanger 10 and provide means for passing a second fluid over the outside surfaces of the tubes when preferably using countercurrent flow of the heat exchange fluids or mediums.