332 



TUBULAR BOILER, SUPERHEATING STEAM, 



determined on constructing an engine for the purpose 

 of more accurately testing those views. 



" MR. GILBERT, " HAYLE FOUNDRY, July 27th, 1829. 



" Sir, Below you have a sketch of the engine that I am 

 making here for the express purpose of experimenting on the 

 working the same steam and water over and over again, heating 



the returned steam by passing it in 

 small streams up through the hot 

 water from the bottom of the boiler. 

 The boiler is 3 feet in diameter, 

 standing perpendicular; the interior 

 fire-tube is 2 feet in diameter ; there 

 is a steam-case round the outside of 

 the boiler with a IJ-inch space. This 

 keeps the boiler hot and partially 

 condenses the steam before it is again 

 forced into the boiler. 



"The boiler is 15 feet high; the 

 cylinder 14 inches diameter, with a 

 6-feet stroke, single power. The pump 

 for forcing the steam and water back 

 again is 10 inches in diameter, with 

 a 2 feet 9 inch stroke, about one- 

 quarter part of the content of the 

 steam-cylinder. The bottom of the 

 boiler will have a great number of 

 small holes, about yVth of an inch 

 in diameter, through which the steam 

 delivered into the boiler will pass up 

 through the hot water, by which I 

 should think it will heat those small 

 streams of steam again to their usual 

 temperature. 



" The pump for lifting water to 

 prove the duty of the engine is 30 

 inches in diameter, with a 6-feet stroke, but this may be length- 

 ened to a 12-feet lift, as the trial or load in the experiments 

 may require, giving from 12 to 241bs. to the inch in the piston. 



