Sectioned model of Niclausse Water-tube boiler

Model (scale 1:10) in longitudinal section in several elements of the Niclausse Water-tube boiler in brickwork setting on mahogany base

The model shows, partly in section, a Niclausse boiler having a brick setting. In this class of water-tube boiler the heating surface is formed by tubes closed at one end and opening at the other into square vertical water chambers, or "headers," while within each tube is a smaller one conveying cooler water from another chamber in the header to the closed end of each double tube, acting similarly to the tubes introduced by Mr. E. Field in 1862. The application of the internal circulating tube to the inclined tubes of boilers of the water-tube type was accomplished by M. Collet, who also introduced the double-chambered header; for the attachment of the outer tubes he, however, employed long internal bolts, and these proved to be unsatisfactory. The practical success of the arrangement is, therefore, due to the work of M. M. Niclausse, who invented and patented, between 1891 and 1900, a form of joint for this purpose which has overcome the difficulties and led to the successful introduction of this system of construction.