Hot-tube Ignitor - Disadvantages

Disadvantages

Hot-tube ignitors had many problems, most caused by the sudden pressure changes in the tube because of the operation of the engine and the high temperature of the tube. It was extremely difficult to find materials that were both durable enough for these conditions and inexpensive.

Also important was never setting the burner flame where it would heat the tube white hot, which would rapidly damage the tube and could cause it to burst explosively. This mistake was made often.

The tubes used were typically 6 to 12 inches long, which tended to make them impractical for use on anything but large engines (e.g., stationary motors in factories). Tubes rarely lasted longer than a year before needing replacement, especially when the engines were fueled with high sulfur gases like unpurified producer gas or natural gas.