How can leaks in the shell be detected in a negative pressure furnace?

Detecting leaks in the shell of a negative pressure furnace is crucial for ensuring safety and efficiency. Employing a smoke stick or ultrasonic test is effective because these methods can visually or acoustically identify areas where air is leaking into the system.

A smoke stick introduces a visible vapor that will be drawn into any leaks, making it easy to see where the air is entering the furnace. This is particularly useful in negative pressure systems, where any leak can significantly impact performance and safety. Similarly, ultrasonic testing can detect the high-frequency sounds produced by air escaping through small leaks, providing a sensitive and reliable way to pinpoint the source of the leak.

Using other methods, such as a pressure gauge or simply listening for hissing sounds, may not provide the same level of accuracy or reliability. Checking the color of the burner flame, while indicative of combustion issues, is not a direct method for identifying leaks in the shell itself. Thus, using a smoke stick or ultrasonic test stands out as the most effective and practical approach for this situation.