Anatomy of a Shell and Tube Heat Exchanger

Shell and tube heat exchangers are the most common type of heat exchanger in oil refineries and large chemical processes and is well suited for high temperature and high pressure applications.  The basic design consists of a shell with a bundle of tubes inside it.  One fluid runs through the tubes while another medium runs over the tubes with the intent of heat transfer between the two fluids.  Heat exchangers with only one phase on each side can be called one phase or single pass heat exchangers.  Two phase heat exchangers can be used to heat a liquid in order to boil it into a gas.

I1 = Heating/Cooling medium inlet at temperature T1

I2 = Heating/cooling medium outlet at temperature T2 – Where T1 is greater than T2

O1 = Inlet of Medium to be heated/cooled at temperature T3 – Where T3 is less than T1

O2 = Outlet of heated/cooled medium at temperature T4 – Where T4 is greater than T2

Heat exchanger flanges may be to “TEMA” standards or to other special designs based on service conditions

Floating head exchanger flange may be to “TEMA” standards or to other special designs based on service conditions

The inlet and outlet connections are typically specified as standard ASME B16.5 pipe flanges.  

Unlike smaller ASME standard pipe flange connections, the body flanges on a large heat exchanger react much differently to the differential pressures and temperatures that are inherent in a typical application.  Due to the relative mass of material and temperature/pressure fluctuations, designers and users should recognize the additional variables this introduces in respect to load retention and sealability. Increased efficiency and reliability can be realized by choosing gasket technologies that are designed to perform specifically in this environment.  Proper bolting materials, lubrication, tightening procedures and the use of a controlled tightening method also contribute to long term reliability.  Contact your Patriot Bolt Representative or Patriot Bolt Engineering for additional information regarding best practices and materials for achieving leak free heat exchangers. 

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