CATALOG OP THE MECHANICAL COLLECTIONS 127 



ment is illustrated by the injectors in the collections, which are 

 described below. 



GIFFARD INJECTOR, 1860 



Plate 27, Figure 1 



U.S.N.M. no. 309368 ; original patent model ; transferred from the United States 

 Patent OflBce; photograph no. 15316C. 



This model was submitted with the application for the patent 

 issued to Henry Giffard, of Paris, France. April 24, 18C0, no. 27979. 



This injector is the first seen in the United States and was made for 

 Giffard by M. Flaud & Co., of Paris, who made the original Giffard 

 injector in 1858. It greatly resembles the first injector, its appearance 

 being characterized by its length and the ring of adjustable windows 

 through which the state of the jet could be examined. 



Within the tube of the injector is a steam nozzle or jet that is 

 opened or closed by a conical plug operated by a crank projecting 

 from the end of the injector. This nozzle projects into the end of a 

 converging tube so that an annular space is foimed around the nozzle 

 tip. This space is connected to the water reservoir, and the effect 

 of the steam rushing into the tube is to entrain the air in the space and 

 form a partial vacuum there, which draws water into the tube. 

 Water entering the tube "has an impulsive force imparted to it by 

 the steam-jet and simultaneously receives a considerable amount of 

 heat therefrom before it enters the boiler." On issuing from the 

 tube the jet of water and condensed steam enters a second tube, which 

 gradually diverges so that the velocity of the water is reduced (and 

 the pressure increased) and the water arrives at the boiler end of 

 the injector with a pressure slightly above boiler pressure and a very 

 low velocity. 



MILLHOLLAND INJECTOR, 1862 



U.S.N.M. no. 309369; original patent model; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to James Millholland, Reading, Pa., June 10, 1862, no 35575. 



The inventor of this very simple injector declared that it could be 

 made for one-twentieth of the cost of the "elaborate and costly 

 Giffard's injector." It consists principally of a casting having a 

 chamber connected to a water inlet and, through a nozzle-shaped 

 bore, to the boiler pipe. A separate steam nozzle projects through 

 the chamber into the opening of the bore. The injector has no 

 valves or overflow opening and requires that the steam supply be 

 controlled by^ a valve in the steam line and that a bypass and suitable 

 cock be provided in the boiler pipe to return the overflow to the 

 water tank when starting. 



