78 BULLETIN 173, U. S. NATIONAL MUSEUM 



CORLISS PUMPING ENGINE, 1879 



U.S.N.M. no. 251291 ; original patent model ; transferred from the United States 

 Patent Oflace; not illustrated. 



Model submitted with the application for patent issued May 27, 

 1879, Patent no. 215803. 



The model shows a compound pumping engine with a high-pressure 

 and a low-pressure horizontal steam cylinder each in line with a 

 pump cylinder. The steam pistons are directly connected to the 

 pump pistons, and a tail rod from each pump piston is connected 

 by a system of oscillating levers to a crank on a flywheel shaft. 

 The flywheel shaft is carried in bearings that are mounted upon the 

 pump cylinders. As is usually the case in engines using steam ex- 

 pansively, the power developed during the admission of steam is in 

 excess of that absorbed by the pumps, and the excess is stored in the 

 flywheel from which it is drawn to carry the load during the ex- 

 pansion of the steam after the steam supply to the cylinder is cut 

 off. The unique feature of the engine is the manner of connecting 

 the piston rods to the cranks. The diameter of the circle in which 

 the crank travels is made much larger than the stroke of the engine 

 with the purpose of making the bearing pressures on the crank and 

 connecting-rod pins smaller and the connecting rods lighter in order 

 to diminish the friction losses in these parts during the transmission 

 of power to and from the flywheel. 



An engine of this design is pictured on page 212 of Thurston's 

 Manual of the SteaTn Engkie, under the caption "Corliss's Pawtucket 

 Engine." 



CORLISS STEAM-ENGINE GOVERNOR, 1882 



U.S.N.M. no. 308715 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent issued 

 to George H. Corliss, August 8, 1882, no. 262209. 



The model represents a flyball governor in which the motion of 

 the slide, owing to a change in the speed of the engine to which the 

 governor is attached, not only changes the position of the cut-off 

 or throttle devices to regulate the speed of the engine but also 

 changes the gear ratio between the engine and the governor to change 

 the speed of the governor relative to the speed of the engine. 



When the governor speed is increased by an increase in the speed 

 of the engine, the balls rise and communicate motion to a slide^ 

 which, in turn, affects the throttle or cut-off to return the engine to 

 its lower speed. At the same time the motion of the slide shifts a 

 friction roller on its driving disk so that the governor speed is in- 

 creased relative to the engine causing an additional motion of the 



