Why does a Steam Heat Exchanger or any Steam Heater have a Steam Trap:

1st reason:

On Outlet line, Steam-out of the Heat Exchanger may also heat or condensated at Steam outlet, therefore, a Steam Trap at Outlet line of Heat Exchanger for trap the Steam to condense into water  before forwarding it to condensate main line (Saving Steam).

2nd reason:

The Steam on the Heat Exchanger may be Water Condensate contaminated, so they have to set Steam Trap with Steam Inlet line to prevent damage from Two-phase flow steam erosion occurred in Heat Exchanger. (Corrosion/Errosion Protection)

Example of Steam Trap between Condensing Steam from Heat Exchanger and Condensate Piping; 

An example of a Steam Trap installed between the Steam outlet line of the Heat Exchanger and the Condensate return line to allow the Heat Exchanger to use the heat energy of steam condensing as much as possible.

Example of Steam Trap connected to Steam Inlet Line of Heat Exchanger; 

An example of a Steam Trap that exits the Steam inlet line of the Heat Exchanger to eliminate condensate mixed with the Inlet Steam to prevent Steam Erosion and damage Heat Exchanger.

 

Why Steam Trap in Steam Transfer Line ?; 

Tubes used in steam or Steam Up Transfer the Line must have a Steam Trap to remove water Condensate and air from Steam makes Steam is in Dry Condition in order to effectively heat exchanger highest. And to prevent Steam Erosion from two-phase flow (Steam + Condensate) overloading with pipes and Heat Exchanger.