What type of gaskets or fittings are used to connect cast iron boiler sections?

The use of internal high-temperature gaskets or push nipples is appropriate for connecting cast iron boiler sections due to the specific requirements for maintaining efficiency and integrity at high operating temperatures. Cast iron sections of a boiler undergo significant thermal expansion and contraction during use, which means that the materials used to create these connections must be able to withstand these fluctuations without compromising the seal or the structural integrity of the system.

Internal high-temperature gaskets are designed to endure the extreme heat generated during the boiler's operation, ensuring that the connection remains secure and leak-free. Push nipples, typically made of durable materials, help to connect the sections while allowing for some movement due to thermal expansion, which is essential in a high-temperature environment.

This combination optimally accommodates the characteristics of cast iron, making this option the most suitable for ensuring that the system operates safely and efficiently.