How are cast-iron sectional boilers held together?

Cast-iron sectional boilers are held together using tie rods, which provide the necessary structural support and stability for the boiler sections. Tie rods are long, heavy-duty bolts that are connected through the sectional pieces. Their primary function is to keep the sections in alignment and prevent them from separating under the internal pressure and thermal expansion that occurs during operation.

The use of tie rods is particularly advantageous in cast-iron boilers because it allows for a form of assembly that can accommodate different thermal expansion characteristics of the various sections, preventing stress and potential damage. This method allows for a robust design while also enabling easier disassembly for maintenance or repair, since the individual sections can be detached without scraping or damaging the surfaces.

Welding is not suitable for cast iron due to the material's properties, which can lead to cracking during the welding process. Screws are not generally used for structural integrity in this type of boiler design, as they do not provide the same level of durability under high-pressure conditions. Clamps could potentially be used for additional support or during assembly, but they are not the primary method for holding the sections together. Thus, tie rods are the most effective solution for ensuring the safe and reliable operation of cast-iron sectional boilers.