PU Engineering’s heat exchangers

Double pipe heat exchangers

A double pipe heat exchanger, in its simplest emergence is just one pipe inside another larger pipe. One fluid flows all the way through the surrounded by pipe and the additional flows throughout the annulus stuck between the two pipes. The wall of the inner pipe is the heat transfer surface. The pipes are usually doubled back multiple times as shown on the picture down, in order to make the overall unit more compact. The term ‘hairpin heat exchanger’ is also used for a heat exchanger of the configuration on the picture. A hairpin heat exchanger may have only one inside pipe, or it may have multiple inside tubes, but it will always have the doubling back feature shown. Some heat exchanger manufacturers advertise the availability of finned tubes in a hairpin or double pipe heat exchanger. These would always be longitudinal fins, rather than the more common radial fins used in a cross flow finned tube heat exchanger. 


Shell and tube heat exchangers

Shell and Tube Heat Exchanger is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. Shell Tubes Heat Exchanger is classified into fixed and floating type Heat Exchangers. Fixed type Heat Exchangers are used where there are absolutely no chances for inter mixing of two fluids.

Shell and tube heat exchangers consist of a series of tubes. One set of these tubes contains the fluid that must be either heated or cooled. The second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required.In this type, the tube sheets are absolutely welded to the shell and acted as shell flanges. The Floating type Heat Exchangers has the advantages of resolvability of tube bundle and access for cleaning both inner and outer side of tubes and shell.


U-tube bundle heat exchangers

A heat-exchanger system consisting of a bundle of U tubes (hairpin tubes) surrounded by a shell (outer vessel); one fluid flows through the tubes, and the other fluid flows through the shell, around the tubes. Multitherm can duplicate any existing bundle to include dimensions, materials and performance. We can build “U” tube bundles, straight tube “floating” tube bundles, or we can re-tube fixed tube sheet heat exchangers when the bundles is not removable. 

The simple design of a shell and tube heat exchanger makes it an ideal cooling solution for a wide variety of applications. One of the most common applications is the cooling of hydraulic fluid and oil in engines, transmissions and hydraulic power packs. With the right choice of materials they can also be used to cool or heat other mediums, such as swimming pool water or charge air. One of the big advantages of using a shell and tube heat exchanger is that they are often easy to service, particularly with models where a floating tube bundle (where the tube plates are not welded to the outer shell) is available. Can also be used on fixed tube sheet heat exchangers. 

u tube