122 BULLETIN 173, U. S. NATIONAL MUSEUM 



the two air ducts, discharging the fuel into the air streams halfway 

 between the fan and the furnace. The system was designed to burn 

 tanbark, culm, sawdust, etc. One feature described is the connection 

 between the smoke box at the forward end of the flue and the fan 

 housing, by which hot gases were returned to the furnace in the mix- 

 ture of air and fuel. Cool air was drawn into the fan through its 

 hollow shaft. 



SALISBURY HYDROCARBON BURNER, 1879 



U.S.N.M. no. 308764; original patent model; transferred from the United States 

 Patent Otfice; not illustrated. 



This model was submitted with the application for the patent issued 

 to Silas C. Salisbury, June 24, 1879, no. 216898. 



The model represents a burner in which two concentric annular 

 chambers are framed around a central hollow tube. The chambers 

 are connected to pipes so that the fuel is fed to the outer chamber, 

 steam to the inner one, while air for combustion is supplied through 

 the centra] tube. The shells forming the annular chambers, and the 

 tube are assembled with long threaded joints, which permit the posi- 

 tions of the parts to be varied for the purpose of controlling the 

 combustion. The inventor described a burner with the forward ends 

 of the shells and tube flared outward as well as one with tlie ends 

 curved inward, either of which would be used depending upon the 

 shape of the fl.ame desired. 



DEXTER HYDROCARBON (OIL) BURNER, 1879 



U.S.N.M. no. 308765 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to Thomas B. Dexter, of Lynn, Mass. (assignor of one-half his 

 right to the Gilmanton Mills, Belmont, N. H.), AugTist 19, 1879, no. 

 218619. 



The model represents a tubular burner with a slightly reduced tip, 

 provided with a vertical diaphragm that divides the burner into two 

 sections. The space on one side of the diaphragm is connected to the 

 oil line and to an air inlet pipe provided with a damper for adjust- 

 ing the flow of air. The other space is connected to the steam line. 

 In operation the flow of steam from the tip creates suction enough to 

 draw the oil and air through the burner. The oil and air are heated 

 by contact with the diaphragm, which separates them from the steam, 

 and are irtimately mixed when they issue from the burner. The 

 diaphragm i-^ notched just inside the tip so that the mixing of the 

 steam and the air and oil results in the formation of a wide, thin, 

 horizontal sheet. This produced a sheet of flame that spread over 

 a large part of the furnace. 



