What is a capillary tube used for?

• A. A device to increase pressure in a refrigerant system
• B. A metering device designed to restrict flow
• C. A method for mixing refrigerants
• D. A heat exchanger in refrigeration systems

Answer: (B)

A capillary tube is primarily used as a metering device in refrigeration systems. It functions by providing a specific restriction to the flow of refrigerant, which is essential for the operation of the system. When the refrigerant flows through the narrow diameter of the capillary tube, it experiences a pressure drop, which helps regulate the amount of refrigerant that enters the evaporator. This process is crucial because it ensures that the evaporator is adequately supplied with the correct amount of refrigerant for efficient heat exchange and system performance.

By restricting the flow, the capillary tube plays a vital role in controlling the system's capacity and maintaining the desired cooling effect. Its simple design and lack of moving parts also contribute to its reliability in various cooling applications.