What is a Bourdon gauge primarily used for?

A Bourdon gauge is primarily used for measuring pressure, particularly in gas systems. It works by translating the pressure within a gas-filled system into a mechanical displacement, which is then displayed on a dial. This functionality is critical in many medical and industrial applications where monitoring the pressure of gases is essential for safety and efficacy.

While transporting gases is an important aspect of managing gas systems, the Bourdon gauge itself does not fulfill that role. Instead, it's used to ensure that the pressure of the gas being transported is within safe and appropriate limits, thereby preventing issues such as leaks or equipment failure.

The other options involve different measurements or functions that are outside the scope of what a Bourdon gauge does. It does not measure flow rate, which is the volume of gas moving through a system, nor does it monitor atmospheric pressure or calculate gas density. These specific functions are typically handled by other types of equipment or gauges designed for those purposes.