What occurs to the bellows in a bellows thermostatic trap when it is heated?

When the bellows in a bellows thermostatic trap are heated, they expand and close the valve. This mechanism is designed to regulate the flow of condensate and steam. As the temperature rises, the bellows, which are typically made from a flexible material, respond by expanding. This expansion pushes against the valve, causing it to close and thus preventing steam from escaping while allowing condensate to pass through.

This function is crucial in managing the efficiency of steam systems, as it helps maintain proper pressure and temperature levels. By closing the valve in response to heat, the bellows ensure that the system operates effectively, preventing steam loss and conserving energy. The interaction of heat with the bellows' material is specifically engineered for this operational purpose, making the system reliable in various heating applications.