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Full text of "The Flow Of Gases In Furnaces"

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DESIGN OF OPEN-HEARTH FURNACES

283


	Gas on Gas
	Air on Air
	Gas on Waste Gas
	Air on
 Waste Gas

7= friction loss between port and valves, revised, kg per m2 or mm of water. . . . d— pressure to impress velocities between port and valves, kg per m2 or mm of water ...
	1.114 3 300
	1.185 2 351
	1.265 4 756
	1.109 2 419

Valve resistance, 5= kg per m2 .....
	4 201
	2 317
	6 216
	4 781


	
	
	
	

Summation, kg per m2 or mm of water . . Chimney effect of checkerwork, etc., kg per m2 or mm of water . .
	8.615 12 851
	6.853 10 683
	12.237 13 217
	8.309 12 990


	
	
	
	

Chimney effect available for port velocity.
	4 236
	3 830
	
	

Draft depression required at reversing valve
	
	
	25.454
	21.299


	
	


	Gas on
 Waste Gas
	Air on Waste Gas

Revised figure for draft depression required at reversing valve, kg per m2 or mm. of water ........       .......
	25.454
	21.299

7= re vised frictional resistance in flue from valve, kg per m2 or mm of water
	0 228
	0 107

5= velocity pressure required in flues from valves ..........
	0.760
	0.730

Revised total draft depression required at point of junction of flues kg per m.2 or mm of water
	26 442
	22 136

T= revised frictional resistance in flue to stack or boiler, kg per m2 or mrn of water              .............
	0 226
	

8= velocity pressure required in stack flue, kg per rn2 or rnm of water .......................................
	1 . 520
	


	
	

Total draft depression required at base of stack or boiler inlet, kg per m2 or mrn of water          .............
	28 . 188
	


	
	

The port areas and velocities may now be fixed. In so doing, it
should be borne in mind that the waste gases must pass out
through the gas- and air-ports in proper proportions to supply the
required amount of preheat. This is very rarely accomplished
when chimney draft is depended upon, particularly when the gas