The steam trap must be able to "identify" steam and condensed water in order to play the role of blocking steam and draining water. The "identification" of steam and condensate is based on three principles: density difference, temperature difference and phase change. Therefore, three types of steam traps are manufactured according to three principles: they are classified into mechanical type, thermostatic type, and thermodynamic type.
Sizing and Installing the Right Traps As long as there is steam passing through, there will be no freezing problems. But if the steam is cut off, the steam condensate will create a vacuum in the heat exchanger or the tracer. This prevents condensate from draining freely from the system before freezing occurs. Therefore, install a vacuum breaker between the device being discharged and the trap. If gravity drainage is not used from the trap to the return line, the trap and discharge line should be manually drained or automatically drained using a freeze-protected drain. Also, when multiple traps are installed together in a trap station, insulating the traps will prevent freezing.
The six antifreeze measures for steam traps are:
1. Insulate the trap discharge line and the condensate return line.
2. If the return pipe is raised, the vertical discharge pipe should be adjacent to the discharge pipe above the return header and insulate the discharge pipe along with the trap discharge pipe.
3. Slope the trap discharge line downward to increase the rate of gravity discharge.
4. Do not oversize the trap.
5. When the condensate return line is exposed to atmospheric conditions, consideration should be given to adding a tracer.
6. Keep the trap discharge line as short as possible.