How is the operation of bellows type steam traps controlled?

Bellows type steam traps operate based on the principle of thermodynamics, specifically utilizing the expansion of vapor from a volatile liquid. When steam enters the trap, it heats the volatile liquid, causing it to vaporize. This vapor expands and causes the bellows to expand as well. The expansion of the bellows in turn opens and closes the trap's discharge valve, allowing condensate and non-condensable gases to escape while preventing steam from being lost.

This method is effective because it relies on temperature differences and the phase change of the trapped fluid to control the flow of condensate, making it a reliable mechanism for steam management in various systems.