Which of the following describes the function of a Bourdon tube?

The Bourdon tube is a crucial instrument used in various applications to measure pressure. It operates based on the principle that the shape of the tube changes in response to internal pressure. As pressure increases, the Bourdon tube tends to straighten out; this movement is then translated into a dial reading, indicating the level of pressure being exerted.

This device is commonly found in pressure gauges, which are essential in HVAC systems for monitoring refrigerant pressure, ensuring the system operates within safe and efficient parameters. Understanding the function of a Bourdon tube is essential for professionals in the HVAC refrigeration field, as accurate pressure readings are vital for system performance and troubleshooting.

The other options pertain to different measurement instruments or methods. Temperature is measured with thermometers, volume can be assessed with flow meters, and density typically requires specialized meters or calculations involving mass and volume. Therefore, their descriptions do not align with the specific capabilities of a Bourdon tube.