Lacashire boiler : A steam boiler having two flues which contain the furnaces and extend through the boiler from end to end.

Example:


Taxonomy
boiler, flue, tube, furnace, flued, Lancashire boiler, fire, Cornish boiler, shell, locomotive, design, pressure, Steam, furnace flue, type boilers, tube diameter, flue gases, Huber.

Defination from the web:
Lancashire boiler is similar to the Cornish, but has two large flues containing the fires instead of one. ... William Fairbairn's work on the Lancashire boiler had demonstrated the efficiency virtues of multiple furnaces relative to a reduced water volume. ...