An ignition arch is specifically used with which type of stoker?

An ignition arch is specifically used with a chain grate stoker due to its design and operational characteristics. The chain grate system involves a continuously moving grate that enables efficient combustion of solid fuels, such as coal or biomass. The ignition arch plays a crucial role in this system as it helps initiate combustion by providing an adequate flame and heat source at the beginning of the fuel bed on the grate.

This arch is positioned at the front of the stoker and directs flames uniformly across the surface of the fuel as it is fed into the combustion chamber. By ensuring that the fuel ignites properly and burns evenly, the ignition arch enhances the overall efficiency and reliability of the chain grate system.

In contrast, other types of stokers, such as cross-feed and underfeed stokers, utilize different mechanisms for fuel feed and combustion, lacking the need for an ignition arch specifically tailored to the chain grate design. Non-pressurized systems generally refer to those that operate without creating internal pressure, but they do not specifically relate to the function of an ignition arch in the context of a chain grate stoker. This makes the chain grate the correct answer, as it requires the ignition arch to facilitate optimal combustion practices.