Product Overview/Sizing | High Pressure Inspirator
Bulletin 3070 Page 2
3070 Inspirators supply a fuel / air mixture to open or sealed- in premix burners by using the energy in high pressure natural gas to induce and mix with combustion air. Gas inlet pressures between 10 and 30 psi are most common but gas pressures up to 100 psi gas can be used. Desired air/gas ratio is set with the air disc at high fire and is maintained reasonably throughout the turndown range, as long as combustion chamber pressure is fairly steady. A gas orifice in the spud is carefully aligned with the machined throat in the body to ensure proper air inspiration and highest possible mixture pressures. Inspirator capacity is affected significantly by the type of installation and pressure conditions within the combustion chamber: Negative pressures (draft) increase inspirator capacity and retard flashback.
Positive pressures reduce capacity, and probability of flashback is greater. At neutral furnace pressures, flashback normally will not occur at mixture pressures above 0.25"w.c. for natural gas. Available turndown depends on mixture pressure, which in turn depends on gas and furnace pressures. Inspirators are primarily on-off devices. INSPIRATORS FOR USE IN OTHER APPLICATIONS
High Pressure Inspirators can also be used for other applications.
— 3070 Inspirator mixers can be used to replace main air blowers in applications where it is difficult to use a traditional blower. See Sheet 3070-1 for details
TABLE 1. NATURAL GAS CAPACITIES AND DEVELOPED MIXTURE PRESSURES (for 0.6 sp gr, natural gas, 1000 Btu/ft 3 , 10 ft 3 air required/ft 3 gas) Gas Flow (cfh) in Bold Type, Mixture Pressures ("w.c.) in Light Type, see page 4 for burner capacities. Inspirator gas pressure, psi Burner gas pressure, psi
Burner
Inspirator
designation 5
10
15 20
25
30
size
designation 5
10
15
20 25
30
size
3070-5 36 201 284 348 402 450
492 -5-B
3070-1 68
17
24 30
34 38
42
-1-A
w/#36 drill
0.48 0.96 1.44 1.92 2.40
2.88
w/#68 drill 0.24 0.48 0.72 0.96 1.20
1.44
3070-6 34 226 320 391 451 505
550 -6-A
3070-1 65
22
32 38
44 49
54
-1-B
w/#34 drill 3.00 3070-6 31 278 393 481 555 621 680 -6-B w/#31 drill 0.52 1.04 1.56 2.08 2.60 3.12 3070-6 30 306 437 536 619 692 757 -6-C w/#30 drill 0.53 1.06 1.59 2.12 2.65 3.18 3070-7 29 352 498 611 705 788 863 -7-A w/#29 drill 0.55 1.10 1.65 2.20 2.75 3.30 3070-7 22 453 640 784 905 1012 1100 -7-B w/#22 drill 0.57 1.14 1.71 2.28 2.85 3.42 3070-7 11⁄64 560 766 938 1082 1210 1350 -7-C w/# 11⁄64 drill 0.59 1.18 1.77 2.36 2.95 3.54 3070-8 3 826 1178 1430 1663 1847 2022 -8-A w/#3 drill 0.62 1.24 1.86 2.48 3.10 3.72 3070-8 C 1038 1468 1800 2075 2325 2550 -8-B w/#C drill 0.64 1.28 1.92 2.56 3.20 3.84 3070-8 J 1462 2068 2535 2935 3270 3585 -8-C w/#J drill 0.66 1.32 1.98 2.64 3.30 3.96 3070-8 5⁄16 1788 2530 3100 3575 4000 4380 -8-D w/# 5⁄16 drill 0.69 1.38 2.07 2.76 3.45 4.14 3070-9 27⁄64 3250 4580 5620 6480 7260 7680 -9 w/# 27⁄64 drill 0.74 1.48 2.22 2.96 3.70 4.44 0.50 1.00 1.50 2.00 2.50
w/#65 drill 0.25 0.50 0.75 1.00 1.25
1.50
3070-2 59
31
43 53
61 69
75
-2-A
w/#59 drill 0.30 0.60 0.90 1.20 1.50
1.80
3070-2 57 36
51 63
72
81
89
-2-B
w/#57 drill
0.31 0.62 0.93 1.24 1.55
1.86
3070-2 55 44
62 76
88 99 108
-2-C
w/#55 drill 0.32 0.64 0.96 1.28 1.60
1.92
3070-2 54
51
71 88 101 113
124 1.98 146 2.22
-2-D
w/#54 drill 0.33 0.66 0.99 1.32 1.65
3070-3 53 60
84 103 119 133
-3-A
w/#53 drill 0.37 0.74 1.11 1.48 1.85
3070-3 52 76 108 131 152 170
186
-3-B
w/#52 drill 0.40 0.80 1.20 1.60 2.00 2.40 3070-4 50 96 136 166 192 215 235 0.41 0.82 1.23 1.64 2.05 2.46 3070-4 46 125 176 216 249 278 305 w/#50 drill w/#46 drill 0.43 0.86 1.29 1.72 2.15 2.58 3070-4 44 138 195 238 275 308 337 w/#44 drill 0.45 0.90 1.35 1.80 2.25 2.70 3070-5 41 168 238 291 336 376 412
-4-A
-4-B
-4-C
-5-A
w/#41 drill
0.47 0.94 1.41 1.88 2.35 2.82
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