CATALOG OF THE MECHANICAL COLLECTIONS H^ 



STEAM-BOILER ACCESSORIES AND BURNERS 



STEVENS SAFETY VALVE, 1825 



Plate 26, Fiqubb 1 



U.S.N.M. no. 180029; origiual; deposited by the Stevens Institute of Technology; 

 photograph uo. 2720. 



Tliis is the safety valve used with the Stevens water-tube boiler 

 of 1803-1825 described above under "Steam Boilers." It is a simple 

 disk valve held closed by a spherical lead weight and stirrup at the 

 end of a lever of the "second-order." The lever or beam of the valve 

 is notched so that the weight can be moved to set the valve to open 

 at different steam pressures. The effective area of the disk is ap- 

 proximately 0.6 square inch; the notches of the lever are 41^, 5%, 

 6%, 8%, 9, and IQi^ inches from the pivot; the center of the valve 

 is 1%6 inches from the pivot; and the ball weighs 3 pounds 14 ounces. 



ROEBLING SAFETY STEAM GAUGE, 1842 



U.S.N.M. no. 308C51 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent issued 

 to John A. Roebling, of Saxonburg, Pa., July 16, 1842, no. 2728. 



The model represents a section of a steam-boiler flue and head to 

 which is attached the safety gauge. The gauge consists of a box 

 fastened to the top of the flue and containing a fusible metal upon 

 which rests a weight connected through a lever to a valve in the 

 boiler head. Should the level of water within the boiler fall below 

 the top of the flue, the fusible metal would melt and allow the weight 

 to fall and open the valve, attracting the attention of the engineer. 

 A rod is provided by which the lever and weight are raised by the 

 engineer before admitting more water, so that the fused metal will 

 solidify below the weight and the gauge be in a position to function 

 again. 



WORTHINGTON AND BAKER "PERCUSSION" WATER-LEVEL GAUGE, 



1847 



U.S.N.M. no. 308052; origiual patent model; transferi'ed from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent 

 issued to Henry R. Worthington, of New York, N. Y., and William 

 H. Baker, of Williamsburg, N. Y., February 20, 1847, no. 4972. 



The model represents a steam-boiler water-level gauge in which a 

 vertical metal cylinder is connected to the boiler so that water and 

 steam stand in the cylinder at the height of the water and steam in 

 the boilers. Within the cylinder is a piston connected to a handle 



