Which type of boiler commonly used Stay Bolts to prevent bulging?

Firetube boilers utilize stay bolts to help maintain the structural integrity of the boiler shell, particularly to prevent bulging caused by internal pressure. These stay bolts are crucial in reinforcing the shell of the boiler and keeping it in shape, especially in areas that are subject to high temperatures and pressures.

In firetube boilers, hot combustion gases pass through tubes that are surrounded by water, and as the pressure and temperature rise inside the combustion chambers, they can cause the outer shell to bulge. Stay bolts provide the necessary support to counteract this force by anchoring the shell to stationary parts of the boiler, thus ensuring that the structure remains stable and safe during operation.

In contrast, water tube boilers have a different design where water flows through tubes that are heated by external fire. Electric boilers generate steam using electric elements and do not face the same pressure distribution challenges as firetube boilers. Steam boilers can refer to various types that might include both firetube and water tube designs, but when specifically considering the prevention of bulging through structural support, firetube boilers are the most relevant type due to their construction and operational conditions.