712 KEW YOEK STATE MUSEUM 



Hoffman ring Jciln. This is used at a number of works in 

 Germany but thus far has not been introduced into the United 

 States. It is circular in form and consists of a number of cham- 

 bers which are connected by flues with a central stack, and also 

 with each other. The fuel is charged through the top and the 

 kiln is down-draft in its action. The fire is started in the first 

 chamber, and the heat from that is used to heat up several of 

 the subsequent ones before it passes off to the stack. The mate- 

 rial is dried preferably in the shape of bricks. 



The advantages are: saving in fuel of 10;^ to 20^; combustion 

 more perfect than in dome kiln; kiln well under control; burning 

 can be watched. The disadvantages are: not economical unless 

 run continuously; material of chamber lining should be as basic 

 as possible to avoid union with silica of cement. 



There are about five different types of kilns in use in the 

 United States at the present time, requiring three different meth- 

 ods of preparation for the raw materials, regardless of differences 

 of preparation which may be required by the character of these 

 materials. The following list quoted from Lewis may serve as 

 partial illustration of this point. 



MANUFACTORY KILN 



Coplay cement co Schof er continuous . . . 



Coplay cement co . Ordinary intermittent 



American cement co., Egypt. " 



American cement co., Jordan " 



Atlas cement co Revolving continuous 



Alpha cement co " 



Vulcanite co " 



Sandusky co " 



Bronson co " 



Empire co Ordinary intermittent 



Glens Falls co Schof er continuous 



Whitecliffs Ark " 



Buckeye cement co Ordinary intermittent 



• • 



Approximate 

 output a day 

 No, Barrels 



9 



55 



23 



30 



56 



30 



6 



30 



20 



150 



8 



150 



3 



150 



4 



120 



3 



120 



18 



130 



8 



60 



8 



60 



« • 



30 



