Which instrument is used to measure the water level in a boiler?

The water gauge glass is specifically designed to measure the water level within a boiler. It provides a direct visual indication of the water level, allowing operators to monitor the amount of water present in the boiler at any given time. This is critical for safe boiler operation, as maintaining the appropriate water level is essential to prevent overheating and potential boiler damage.

The gauge glass typically features two chambers that allow operators to see both the water level and its fluctuations in real-time. This visual feedback is crucial for preventing hazardous conditions such as boiling dry, which can lead to serious accidents.

In contrast, a thermometer measures temperature, a pressure gauge measures internal pressure, and a flow meter measures the flow rate of water or steam. While all these instruments serve important functions in boiler management and safety, they do not provide information specifically about the water level, making the water gauge glass the correct choice for this purpose.