Rich Operation Capacity | High Pressure Inspirator
TABLE 3. FACTORS FOR RICH OPERATION AND FOR OTHER GASES % air gas
spud area
gas specifications
thru
capacity and mixture
Btu/ft 3
kWh/Nm 3
MJ/Nm 3
sp gr air/fuel ratio Inspirator
factor
press. factor
90 80 70
0.83 0.67 0.53 1.25 1.03 0.83 0.66
1.21 1.50 1.90 0.85 1.02 1.28 1.60
1000
10.35
37.26
0.60
10
100
90 80 70
1200
12.42
44.71
0.70
11.7
Example: Non-standard selection. Inspirator to supply 80% air for 300 cfh of 20 psi 1000 Btu/ft 3 gas.
standard drill is #44 with 0.00581 sq. in. area. Therefore, specify a 3070-4 Inspirator with #44 spud drill. To find actual mixture pressure, multiply 1.64 × 1.50 = 2.46"w.c. Propane and butane does not inspirate as much air in a 3070 mixer as high pressure natural gas. To use propane, butane, or low-pressure gases in an open-air torch, see Bulletin 4696 “Gas- Compressed Air Torches”
In Table 1, read a 0.67 capacity factor and a 1.50 spud and mixture pressure factor. The required 300 cfh capacity × 0.67 = 201 cfh equivalent capacity. In the left half of Table 1, look down the 20 psi gas pressure column until you find a gas flow near 201 cfh. 192 cfh corresponds to a 3070-4 50 tentative inspirator size and drill designation and 1.64"w.c. tentative mixture pressure. The last number means #50 spud drill, which has 0.00385 sq. in. area (from any drill size table). Multiply this by the spud area factor, 0.00385 × 1.50 = 0.00578 sq. in. The next larger
TABLE 4. OPTIONAL 3070 GAS INLET ACCESSORIES
Gas Inlet Size
Shutoff Valve (Ball Valve)
Needle
NPT/BSPT
Quick
inches NPT
Valve
Inlet Adapter
Disconnects
3⁄8
3070-1 3070-2 3070-3 3070-4 3070-5 3070-6 3070-7 3070-8 3070-9
1821B-02
1837-02
R590-0212
8775-02
½
1821B-01
1837-01
R590-0213
8775-01
¾
1821-0
1837-0
R590-0214
8775-0
1
1821B-1
1837-1
R5690-0215
8775-1
1 ½
1821B-3
1837-3
NA
NA
For additional accessory information see: Bulletin 8735 for gas pressure gauge options Bulletin 8773 or flexible braided hoses Bulletin 8770 for Quick Disconnects Sheet 8771 for BSPT (ISO7) NPT Adapters
Bulletin 3070 Page 5
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