(under subclass 136) Devices having horizontally disposed small fire tubes, through which the products of combustion are returned through the boiler after leaving the large flues. The firebox is generally located in the large flues.
SEE OR SEARCH THIS CLASS, SUBCLASS:
47, for miscellaneous boilers having fire tubes with a horizontal flue.
74, 76 and 107, for related art in the fire tube type of boiler.
141, 146, 150, 151, and 410, for other types of horizontal flue boilers having return fire tubes.
