MECHANICS AND USEFUL ARTS. 



BOILER TUBES. 



MR. JAMES BANNISTER has received a patent for some " improve- 

 ments in tubes for locomotive and other hoilers," which relate to the 

 making of the tubes by the combination into one of three tubes of dif- 

 ferent metals, and to a mode of manufacturing tubes of copper, brass, 

 and other alloys of copper. In the first part of the invention, three 

 tubes of different metals are employed, brass, iron, and copper being 

 the metals. These tubes are placed one within the other, the brass 

 tube on the interior, the iron next, and the copper on the exterior. A 

 slightly tapering mandril is then introduced, and the tubes are drawn 

 through a series of dies till they are closely combined. By this mode 

 of construction, the advantage is obtained of having the beneficial re- 

 sults consequent on using brass where the rush of flame comes, togeth- 

 er with the advantage of having the copper next the water, while the 

 whole is stiffened by the iron. When, however, the fire is to act ex- 

 ternally, the order of arrangement should be reversed. 



The second part of the invention consists of a new means of joining 

 the seams of tubes of copper, or brass, and other alloys of copper. The 

 metal is to be bent over into the form of a tube, so that the edges come 

 together, and then, by the edge of a triangular file, remove the edges 

 of the metal, so as to form as it were an angular gutter. The tube 

 is then filled with sand, and the exterior covered with it, leaving a gut- 

 ter in the sand so as to increase the size of that made by the coming 

 together of the chamfered edges of the metal, and in this condition 

 the tube is heated to a bright-red heat. Melted metal, similar to that 

 used for the tube, is then poured into the gutter, which will partially 

 fuse the eda;es of the tube, and then the whole will set into a solid 



o ' 



mass. When it is cold the projecting ridge of metal at the seam is 

 removed. This is best done by passing it in contact with a circular 

 saw. The tubes thus made are passed two or three times between 

 grooved rollers, having a mandril in them, and are then completed by 

 drawing through dies with a mandril, as is usually done with other 

 tabes. Civil Engineer and Architect's Journal, July. 



SAFETY-VALVE. 



AT Messrs. Stonehouse and Co/s office is being exhibited a new 

 invention to be applied to steam-boilers. From the hollow standard 

 of the float-pulley, near the boiler, springs a short elbow-pipe, the up- 

 per orifice of which is a small safety-valve ; and from the chamber on 

 which it works rises a tube, terminating with a whistle. The valve 

 is held down by a lever and weight, the fulcrum of the lever being a 

 short standard on one side of the valve. But the lever is prolonged 

 backwards also, passing through a slant in the main standard, and ter- 

 minating in an eye, which loosely embraces the float-rod. On the 

 valve-box there is a sscond small standard, opposite the one forming 

 the lever, projecting backwards, and also embracing the float-rod. 

 This second lever is likewise jointed to the safety-valve rod, but there 

 is no weight on it. On the float-rod, and between the eyes of the two 



