CAPB-101 - page 7

7
Blower capacity tables are based on
standard air at 70°F and sea level.
For other operating conditions,
correct the required Static Pressure
(SP) before using the rating tables.
The BrakeHorsepower (BHP) is
corrected after blower selection
has beenmade.
EXAMPLE:
Select a pressure blower tohan-
dle 1000 CFMat 2.75" SP, 100°F
and at 1000 feet above sea level.
Refer to the Temperature/Altitude
table. At 1000 feet and 100°F, the
correction factor is 1.10.
Temperature and Altitude Correction
Correction factors
for temperature (F)
and altitude (above sea
level); standard air = .075
lbs.per cubic foot at sea
level, 29.92” barometric
pressure and 70° F
-15
0
70
100
150
200
.79
.87
1.00
1.06
1.15
1.25
.81
.88
1.02
1.08
1.17
1.27
.82
.90
1.04
1.10
1.19
1.29
.84
.92
1.06
1.12
1.22
1.32
.85
.93
1.08
1.14
1.24
1.34
.87
.95
1.10
1.16
1.26
1.36
.88
.97
1.12
1.18
1.28
1.39
AIR
TEMP
(F°)
29.92
500´
29.38
1000´
28.86
1500´
28.33
2000´
27.82
2500´
27.31
3000´
26.82
3500´
26.32
ALTITUDE (feet) withBAROMETRICPRESSURE (HG)
Refer to Chicago Blower’s
Selection program, fan.net,
for performance, fan curves
and sound data. Contact
your local Chicago Blower
sales engineer for software
and assistance.
.90
.99
1.14
1.20
1.31
1.42
Corrected SP is 1.10 X 2.75" SP =
3.025" SP at 70°F and sea level.
To simplify, use 3.00"SP.
FOR DIRECT DRIVE
Using the Direct Drive Performance
tables, enter the tables at the
required Static Pressure, 3.00" SP.
Reading down the column, find
the CFM rating(s) thatmeet the
required 1000 CFM. Several
blowersmeet this requirement,
one of which is aModel 1400with
a 12-1/4" x 2-7/8"wheel and 6"
inlet. The blower will run at 3450
RPM and require 2.46 BHP at 70°F
and sea level.
Correct the BHP. Divide 2.46 by the
correction factor (1.10). 2.46÷ 1.10=
2.24BHP at 100°F and 1000' altitude.
FOR BELT DRIVE
Using the Belt Drive Performance
tables, one selection for 1000CFM at
3" SPwould also be aModel 1400.
The blower will run at 2470 RPM and
require 1.45 BHP at 70°F and sea
level. (Actual RPM and BHPwas cal-
culated by interpolating between the
1050 and 900 CFM in the tables.)
Correct the BHP. Divide 1.45 by the
correction factor (1.10). 1.45 ÷ 1.10 =
1.32 BHP at 100°F and 1000' altitude.
NOTE:
When several ratingsmeet the
requirements, usually the lowest
brake horsepower requirement
will provide themost efficient
andquietest selection.
PRESSURE BLOWER SELECTION
Identical performances can be
achieved by different blower
sizes by varying the wheel
widths and diameters. Often
installation requirements will
determine the blower size.
1,2,3,4,5,6 8,9,10,11,12,13,14,15,16
Powered by FlippingBook