TEMA TYPES
For a graphical representation of the various TEMA types click HERE.
For a Tabular representation of the various TEMA types Click HERE.
In order for you to better understand the process of selecting a TEMA type, refer to the general selection criteria for the most common TEMA types.
Removable
Bundle Exchangers
Listed by Increasing Cost
Removable bundle exchangers give the customer the ability to replace the tube bundle without replacing the shell or bonnets. They are generally less cost effective than non removable designs.
BEU/AEU- U Bundle Exchangers are generally the most cost effective design style of removable bundle exchanger. Tubes may be water blasted, steam or chemically cleaned. These units must have an even number of tube passes, sometimes limiting their applicability to a service(e.g. they generally can not be used when a temperature cross occurs).
CEU- This design has the tubesheet welded to the bonnet. You can remove the bundle from the shell, however to replace the bundle, the inlet bonnet is included or you must cut off the tubesheet. Tubes may be chemically cleaned, water blasted or steam cleaned.
BEW/AEW- These are straight tube units with one floating head and one stationary head. The floating head is generally sealed with an O-Ring. These units are most often used as oil coolers or air coolers. Cleaning can be performed by either a chemical, mechanical method, water blast or steam cleaning.
AEP/BEP- These are straight tube units with one inside packed floating head and one stationary head. The floating head is generally sealed with packing. These units are most often used as intercoolers and aftercoolers with the gas on the tube side. They are also the most common style for oxygen service exchangers. These units have been used in services with tube side design pressures in excess of 2000 PSIG.
AES/AET- These units are the most expensive of the removable bundle designed units. The floating head is internal to the shell. Tubes can be cleaned mechanically , chemically, water blasted or steam cleaned. The design of these units forces an even number of tube side passes therefore they suffer the same service restrictions as U bundles. Although in theory one pass unit can be designed, this is rarely done. These units are generally used in services where U bundles are not desired and the service may be too corrosive/damaging to the packing used in AEP/BEP units.
Non
Removable Bundle Exchangers
Listed by Increasing Cost
These types of units are often used in high pressure services and services where you wish to avoid leakage problems at gasketed joints. Another advantage is that they are generally more cost effective than removable bundle designs.
NEU- The most cost effective design available. The tubesheet is welded to both the shell and bonnet. There is no access to the shell. Tubes may be chemically cleaned, water blasted or steam cleaned from inside only. These units are commonly used in high pressure services (such as feedwater heaters), where process conditions allow for even pass exchangers.
NEN- Tubesheets are welded to both the Shell & Bonnets. Access to the tubes is through covers on the channels. These units are favored in very high pressure designs as their construction minimizes the tubesheet thickness and number of high pressure retaining flanges.
AEM/BEM/AEL-Shell side is completely welded up, however, the bonnets are removable. Chemical, mechanical, and water blast cleaning of the tubes is possible, however you do not have access to the shell.
You should avoid using Steam cleaning on a fixed tube sheet unit unless the unit has a shell side expansion joint. The steam will cause the tubes to expand and pull out of the Tube Sheet causing failure at startup.