Measares to secure a patent for the above have been taken by Benjamin Irving, oi Greenpoint, L. I. This form of boiler has great merits in the essential point—of consi derable heating surface in a small compass whilst a small quantity of water suffices tc cover the heated plate, and in consequence steam is rapidly generated. But although quick in operation it is emphatically a safe boiler, as the system of circulation, which is one of its leading traits enables a very small quantity of water to keep the flue plates from injury. It is, however, almost impossible foi the water level to be reduced by accident tc such a degree as to be dangerous, and more over the form is so strong that braces or stays are not required. The outer shell consists ol a vertical cylinder containing a smaller one nearly as high, the annuiar space thus formed is closed at each end by a plate, whilst a se ries of flue tubes are arranged inside the an nular space. Each cylinder terminates at the top in a dome, that of the outer cylinder touch ing the inner dome (which is the steam cham ber) near the vertex. A smaller cylinder is situated inside the two just described, and it is united to the inner one some distance from the top, but the lower end does not reach to the bottom; this contains a fourth cylinder united to it at the bottom, and ending in a dome at the top. The fire grate is circular and lies below the two latter cylinders. Two coils of pipe are placed within the smallest cylinder, and communicate with the lowest part of the two outer cylinders, their upper ends passing through the dome to the steam chamber. That space between the outer shell and con tained cylinder, which is not engrossed by the flue tubes, is used as a " water jacket," and a similar water space exists between the two inner cylinders, these water spaces being con nected. A coil of pipe, led through the above spaces, will serve either to dry or to generate the steam. The gases, as they rise from the fuel, proceed up the innermost cylinder, thence between the two- others, whilst the products of combustion descend and from a circular passage escape through the flue tubes into a space that conducts to the chimney.
This article was originally published with the title "Improved Steam Boiler"