134 BULLETIN 173, U. S. NATIONAL MUSEUM 



The inventor refers to this as an improvement on the invention of 

 "a new and improved method of insuring the action of steam valves 

 in direct-acting pumping engines", patented by himself and William 

 H. Baker, April 3, 1849. 



WORTHINGTON "DUPLEX" STEAM PUMP, 1859 



U.S.N.M. uo. 251300 ; original model ; transferred from the United States 

 Patent OflSce ; not illustrated. 



This model was part of the application for the patent issued to 

 Henry K. Worthington, of Brooklyn, N. Y., July 19, 1859, no. 24838. 



This is a 2-cylinder, direct-connected steam pump in which the 

 steam and exhaust valves of each steam cylinder are actuated in 

 part by the motion of the piston in the other cylinder. The "du- 

 plex" pump has had a wide application as a boiler feed-water pump. 



The engine consists of two horizontal double-acting steam cylin- 

 ders, each directly connected to a double-acting pump cylinder. In 

 operation steam is admitted to one steam cylinder forcing the piston 

 to move, until at some position in its stroke it engages a series of 

 levers that open the steam valve of the other cylinder. The piston 

 continues on until it engages a second lever, which shuts off the 

 steam to its cylinder and the piston comes to rest. Meanwhile the 

 second piston, moving through its stroke, actuates levers that open 

 the steam valve to the first cylinder and causes the first piston to 

 start on its return stroke. The second piston continues to move until 

 it closes its own steam valve and then remains at rest until its steam 

 valve is opened by the movement of the first piston, and so on. 



This arrangement of valves produces a positive motion of the 

 pump, prevents "short-stroking", and provides the action of at least 

 one piston upon the water at all times, thereby reducing shock or 

 pounding in the water discharge. 



SEWELL AND CAMERON STEAM PUMP, 1864 



U.S.N.M. no. 808669; original patent model; transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for the patent is- 

 sued to William Sewell and Adam S. Cameron, of Nev/ York, N. Y., 

 May 10, 1864, no. 42694. 



The model represents a direct-connected steam pump in which the 

 water piston rod is keyed in a socket in the end of the steam piston 

 rod, so that the two may be disconnected when it is desired to oper- 

 ate the pump by hand. The socket is sufficiently long to serve as a 

 guide for the water piston rod, and a suitable rock shaft and capstan 

 head is provided for working the pump by hand. 



The purpose of the combination is to provide a hand pump for the 

 various purposes for which a pump might be required aboard a 



