Eclipse ImmersoJet v2.20 Design Guide 330, 10/02
Application example:
A designer of a spray washer has determined the heat input for the
water tank requires 857,500 Btu/hr. Based on the size of his tank,
he has selected a tube efficiency of 70% which results in a gross
burner input of 1,225,000 Btu/hr.
Calculation example to determine the air flow
requirement:
a. Decide which ImmersoJet model is appropriate:
• From the capacity table, either the 4” with a remote
blower (1,800,000 Btu/hr), or the 6” with the low-
pressure packaged blower (2,000,000 Btu/hr) have
sufficient capacity. For this example, the designer selects
the 4” tube because his tank size limits the amount of the
larger 6” tube that will fit.
• Select an IJ004, 4” diameter tube ImmersoJet burner with
a remote blower for a maximum firing rate of 1,225,000
Btu/hr.
b. Calculate the required gas flow:
V
gas
= Q/q = 1,225,000 Btu/hr / 1,002 Btu/ft
3
= 1,223 ft
3
/hr
• Gas flow of 1,223 ft
3
/hr is required.
c. Calculate the required stoichiometric air flow:
V
air-stoichiometric
= a (air/gas ratio) x V
gas
= 9.41 x 1,223 ft
3
/hr
= 11,508 ft
3
/hr
• Stoichiometric air flow of 11,508 scfh required
d. Calculate the final blower air flow requirement based on 15%
excess air at high fire:
V
air
= ( 1 + excess air %) x V
air-stoichiometric
= ( 1 + 0.15) x 11,508 ft
3
/hr = 13,234 ft
3
/hr
• For this example, final blower air flow requirement is
13,234 scfh at 15% excess air.
n
Note:
It is common practice to add an additional 10% to the final
blower air flow requirement as a safety margin.
3. Find the blower model number and motor horsepower (hp).
With the output pressure and the specific flow, you can find the
blower catalog number and the motor hp in Bulletin 610.
4. Select the other parameters:
•
inlet filter or inlet grille
•
inlet size (frame size)
•
voltage, number of phases, frequency
•
blower outlet location, and rotation direction Clockwise
(CW) or Counter Clockwise (CCW).
C
OMBUSTION
A
IR
S
YSTEM
(
CONTINUED
)
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