THK EAST RIVER AM) TIIK UUOOKI.YX BRIDGES FROM THE SINGER TOWER 



furnace and tin- exhaust of gases from the furnace 

 are under perfect control and bear a fixed relation 

 to each other for all rates of combustion. Ha hi need 

 Draft, therefore, checks the waste of coal by auto- 

 matically van-ing both the air supply to the furnace 

 and the throttling of the gases passing to the chimney, 

 thereby controlling the combustion according to the 

 evaporation, and maintaining it at its maximum effi- 

 ciency under all conditions of load on the boiler. 



That the Balanced-Draft System plays a very 

 important part in the economy of the boiler plant in 

 the Singer Building is very clearly shown by the 

 results of the official tests, which indicate the evap- 

 oration from and at 212 F. of 10.3 pounds of water 

 per pound of \o. 2 buckwheat coal costing $2.75 

 per ton delivered. 



It is interesting to note that this plant develops a 

 kilowatt hour from three pounds of No. 2 buck- 

 uheat coal at a cost of 1 % of a cent. These 

 K-MilK clearly demonstrate the plant in the Singer 

 Building to be one of the most economical in 

 the country and to compare very favorably with 

 the great electric-power generating plants. The 

 effect of limiting the air supply by the Balanced- 

 Draft System is clearly shown by the CO2 recorder, 

 which shows an average of 16 per cent. COz in the 

 flue gases while the foregoing results are being ob- 

 tained. 



SMOKE BREECHING AND IHVT FOR 

 BALANCED DRAFT 



THE smoke breeching for the buttery of five 

 boilers, aggregating about ^.OOO nominal II. P., con- 

 sists of No. 10 gauge black iron stiffened with 2^- 

 inch angle irons placed 3 feet on centers. There 

 are several clean-out doors and a main damper on 

 roller bearings. On account of its great size it was 

 made of two sheets of steel riveted together with 

 channel braces. 



The breeching is 4 ft. x (5 ft. 6 in. at the ex- 

 treme end and increases gradually to (J ft. (> in. 

 x 9 ft. where it enters the vertical smoke stack. It 

 is covered throughout its entire length with "2 inch H;> 

 per cent, carbonate of magnesia blocks, on a wire lath 

 foundation, leaving an air space of 1 inch between 

 the covering and the flue. The outside is finished 

 with magnesia plaster having a hard, smooth finish. 



The entire equipment was installed by Edtrin 

 linrlinrn. No. 71 Wall .Street, who also furnished the 

 galvani/ed-iron duct work connecting the balanced - 

 draft blower with the ashpits of the boilers. This 

 work is constructed of galvanized iron up to the rear 

 wall and of hard-burned salt-glased tile pipe under 

 each boiler. To install it so as not to interfere 

 with the concrete foundations required considerable 

 ingenuity. 





