Mechanical
Mechanical traps sense the difference in density between steam and condensate. The two main types of mechanical traps are: (1) inverted bucket and (2) float/float & thermostatic. Inverted bucket traps feature an upside-down bucket inside the trap housing. The bucket is free to move in the vertical direction. When steam is in the trap, it lifts the bucket which causes the orifice to close. When the steam in the trap condenses and/or when condensate enters the trap, the bucket falls, the orifice opens, and condensate discharges. Most inverted bucket traps incorporate a small bleed hole to allow any air in the system to escape. Inverted bucket traps are the most robust choice for steam jacketed systems as they require no special considerations. Float traps feature a ball float inside the trap housing. When steam or air is in the trap, the ball rests on the trap floor. When condensate enters the trap, the ball floats on the condensate and rises, the orifice opens, and condensate discharges. The orifice is located in the liquid level, requiring additional air purging capability to avoid air lock. Provided some form of continual air purging is incorporated in the trap design, float traps can function well in a steam jacketed system.