Part 31 (2/2)

AVAILABLE DRAFT

CALCULATED FOR 100-FOOT STACK OF DIFFERENT DIAMETERS assUMING STACK TEMPERATURE OF 500 DEGREES FAHRENHEIT AND 100 POUNDS OF GAS PER HORSE POWER

FOR OTHER HEIGHTS OF STACK MULTIPLY DRAFT BY HEIGHT 100

+-----+-------------------------------------------------------------------+ |Horse| | |Power| Diameter of Stack in Inches | +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | |36 |42 |48 |54 |60 |66 |72 |78 |84 |90 |96 |102|108|114|120|132|144| +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 100 |64| | | | | | | | | | | | | | | | | | 200 |55|62| | | | | | | | | | | | | | | | | 300 |41|55|61| | | | | | | | | | | | | | | | 400 |21|46|56|61| | | | | | | | | | | | | | | 500 | |34|50|57|61| | | | | | | | | | | | | | 600 | |19|42|53|59| | | | | | | | | | | | | | 700 | | |34|48|56|60|63| | | | | | | | | | | | 800 | | |23|43|52|58|61|63| | | | | | | | | | | 900 | | | |36|49|56|60|62|64| | | | | | | | | |1000 | | | |29|45|53|58|61|63|64| | | | | | | | |1100 | | | | |40|50|56|60|62|63|64| | | | | | | |1200 | | | | |35|47|54|58|61|63|64|65| | | | | | |1300 | | | | |29|44|52|57|60|62|63|64|65| | | | | |1400 | | | | | |40|49|55|59|61|63|64|65|65| | | | |1500 | | | | | |36|47|53|58|60|62|63|64|65|65| | | |1600 | | | | | |31|43|52|56|59|62|63|64|65|65| | | |1700 | | | | | | |41|50|55|58|61|62|64|64|65| | | |1800 | | | | | | |37|47|54|57|60|62|63|64|65| | | |1900 | | | | | | |34|45|52|56|59|61|63|64|64| | | |2000 | | | | | | | |43|50|55|59|61|62|63|64| | | |2100 | | | | | | | |40|49|54|58|60|62|63|64| | | |2200 | | | | | | | |38|47|53|57|59|61|62|64| | | |2300 | | | | | | | |35|45|52|56|59|61|62|63| | | |2400 | | | | | | | |32|43|50|55|58|60|62|63| | | |2500 | | | | | | | | |41|49|54|57|60|61|63| | | |2600 | | | | | | | | | |47|53|56|59|61|62|64|65| |2700 | | | | | | | | | |45|52|55|58|60|62|64|65| |2800 | | | | | | | | | |44|59|55|58|60|61|64|65| |2900 | | | | | | | | | |42|49|54|57|59|61|63|65| |3000 | | | | | | | | | |40|48|53|56|59|61|63|64| |3100 | | | | | | | | | |38|47|52|56|58|60|63|64| |3200 | | | | | | | | | | |45|51|55|58|60|63|64| |3300 | | | | | | | | | | |44|50|54|57|59|62|64| |3400 | | | | | | | | | | |42|49|53|56|59|62|64| |3500 | | | | | | | | | | |40|48|52|56|58|62|64| |3600 | | | | | | | | | | | |47|52|55|58|61|63| |3700 | | | | | | | | | | | |45|51|55|57|61|63| |3800 | | | | | | | | | | | |44|50|54|57|61|63| |3900 | | | | | | | | | | | |43|49|53|56|60|63| |4000 | | | | | | | | | | | |42|48|52|56|60|62| |4100 | | | | | | | | | | | |40|47|52|55|60|62| |4200 | | | | | | | | | | | |39|46|51|55|59|62| |4300 | | | | | | | | | | | | |45|50|54|59|62| |4400 | | | | | | | | | | | | |44|49|53|59|62| |4500 | | | | | | | | | | | | |43|49|53|58|61| |4600 | | | | | | | | | | | | |42|48|52|58|61| |4700 | | | | | | | | | | | | |41|47|51|57|61| |4800 | | | | | | | | | | | | |40|46|51|57|60| |4900 | | | | | | | | | | | | | |45|50|57|60| |5000 | | | | | | | | | | | | | |44|49|56|60| +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

FOR OTHER STACK TEMPERATURES ADD OR DEDUCT BEFORE MULTIPLYING BY HEIGHT 100 AS FOLLOWS[52]

For 750 Degrees F Add 17 inch

For 700 Degrees F Add 14 inch

For 650 Degrees F Add 11 inch

For 600 Degrees F Add 08 inch

For 550 Degrees F Add 04 inch

For 450 Degrees F Deduct 04 inch

For 400 Degrees F Deduct 09 inch

For 350 Degrees F Deduct 14 inch

[Graph: Horse Power of Boilers against Dia 33 Diameter of Stacks and Horse Power they will Serve

Computed from Formula (28) For brick or brick-lined stacks, increase the diaht and Diameter of Stacks--From this formula (27) it becomes evident that a stack of certain diaht, will produce the saer dia required to overco the various stacks that would meet the requirements of a particular case there must be one which can be constructed more cheaply than the others It has been determined from the relation of the cost of stacks to their diahts, in connection with the formula for available draft, that the minimum cost stack has a diameter dependent solely upon the horse power of the boilers it serves, and a height proportional to the available draft required

assuas per hour for each boiler horse pohich provides for ordinary overloads and the use of poor coal, the ives:

For an unlined steel stack--

diameter in inches = 468 (H P){2/5} (28)

For a stack lined with masonry--

diameter in inches = 492 (H P){2/5} (29)

In both of these formulae H P = the rated horse power of the boiler

Fro 33, has been calculated and from it the stack diameter for any boiler horse power can be selected

For stoker practice where a large stack serves a number of boilers, the area is usually made about one-third e of air through the setting of any idle boilers, irregularities in operating conditions, etc

Stacks with diaive an available draft which bears a constant ratio of the theoretical draft, and allowing for the cooling of the gases in their passage upward through the stack, this ratio is 8 Using this factor in forht of the chimney becoht of stack in feet above the level of the grates, d{1} = available draft required, K = constant as in formula