Vertical boiler

A vertical boiler is a fire-tube or water-tube boiler where the barrel is oriented vertically, differing from the more common horizontal design. It was widely used in steam-powered vehicles and mobile machinery, including early locomotives.

Design considerations include various tube arrangements, such as vertical fire-tubes, cross-tubes, and spiral water tubes. Advantages of vertical boilers include a small footprint, making them suitable for space-constrained vehicles; easier maintenance, as they can be replaced without dismantling the entire machine; and better tolerance for uneven water levels during operation on inclines.

Disadvantages include larger size due to height requirements, limiting their use in confined spaces; limited grate area affecting steam production; short tubes causing heat loss through chimneys; and sediment buildup insulating water from heat, risking damage to the bottom tube sheet.

Vertical boilers were applied in various fields:

Overall, vertical boilers offered versatility across industries but faced limitations in size and efficiency.