What is the function of the bellows in a thermal expansion valve?

The bellows in a thermal expansion valve plays a critical role in controlling the flow rate of refrigerant within a refrigeration or air conditioning system. The design of the bellows allows it to respond to pressure changes that correspond to the temperature of the refrigerant. As the temperature of the refrigerant increases, the pressure within the system also rises, causing the bellows to expand. This expansion adjusts the opening of the valve, allowing more or less refrigerant to flow into the evaporator based on demand.

This dynamic control ensures that the system maintains optimal operating efficiency by supplying the right amount of refrigerant required to absorb heat and maintain desired temperature levels. The ability to adjust the flow rate in response to varying thermal loads is essential for achieving efficient cooling and energy usage. Therefore, the primary function of the bellows is indeed to control the refrigerant flow rate.