What type of mechanism is primarily used in float steam traps to sense water level?

Float steam traps utilize a float mechanism to sense the water level within the trap. When steam condenses into water, the float rises and falls with the changing water levels. This movement directly affects the operation of the trap, allowing it to open or close based on the water level. The float ensures that the trap efficiently drains condensate while preventing steam loss.

In contrast, the other mechanisms mentioned do not serve this purpose effectively. The centrifugal mechanism operates based on rotational force and is not designed for level sensing. Thermostatic elements rely on temperature changes to operate, which is unsuitable for detecting water level specifically. Pressure gauges measure pressure rather than liquid levels, making them ineffective for the function required in float steam traps. The reliance on the float mechanism is critical for the efficient operation of these traps, ensuring that they react promptly to changes in condensate levels.