TEMA DESIGNATIONS
BEM: Bonnet (Integral Cover), One Pass Shell, Fixed Tube sheet Bonnet
Fixed tube sheet heat exchanger. Is a version with one shell pass and two tube passes and a very popular version as the heads can be removed to clean the inside of the tubes. The front head piping must be unbolted to allow the removal of the front head, if this is undesired this can be avoided by applying a type A front head. In that case only the cover needs to be removed. It is not possible to clean the outside surface of the tubes as these are inside the fixed part. Chemical cleaning can be used
BEM: This is the same type of heat exchanger as above, but with one tube pass.
AEM: Channel with Removable Cover, One Pass Shell, Fixed Tube sheet Bonnet.
AES: Channel and Removable Cover, One Pass Shell, Floating Head with Backing DeviceFloating Head Heat Exchanger. A floating head is excellent for applications where the difference in temperature between the hot and cold fluid causes unacceptable stresses in the axial direction of the shell and tubes. Notice that the bundle cannot be pulled from the front end. For maintenance both the front and rear end head, including the backing device must be disassembled. If pulling from the front head is required, a type AET should be selected.