A
Leader in Silencing for Industry
Rotary Positive Blower
Silencers
|
Model |
|
| 122 | 4.4 |
| 131 | 4.4 |
| 141 | 4.4 |
| 141 12" & Larger | 5.5 |
| 144 | 5.5 |
Rotary Positive Blowers are two impeller compressors that function like a high speed reciprocating compressor. Each revolution will displace a large quantity of gas relative to the individual pulse; each revolution
will produce (4) pulsations. Blower capacities are expressed in ICFM (Inlet Cubic Feet per Minute). The manufacturer typically specifies blower size by connection size, gear diameter and rotor length. Pitch Line Velocity (PLV) is the gear circumference multiplied by the RPM usually expressed in feet per minute (FPM).Blower applications involve two acoustic problems, pulsation (4/Revolution) which cause pipe vibration, and high audible noise levels radiating from the blower housing and piping. Pulsation and noise increase proportionately with blower size and the square of the RPM.
Silencer size and type is determined based on allowable pressure drop and flow, noise reduction required (DIL). The nominal size (nozzle/connection size) of the silencer is based on flow (ICFM). However, the silencer type is selected based on consideration of blower size (gear PLV).
Silencer type will typically be either a reactive chambered design or a combination reactive/absorptive design. Both inlet and discharge connections will require a silencer.
PITCH LINE VELOCITY (PLV) SELECTION RECOMMENDATIONS:
| INLET | 3300 FPM(PLV) |
Below 3300 FPM reactive silencers are appropriate
Over 3300 FPM combination reactive/absorptive are appropriate.
| DISCHARGE | 2700 FPM (PLV) |
Silencers should be mounted directly to the blower to avoid standing wave resonances that can develop by extending the connection length.
:
|
BLOWER GEAR SIZE |
TRANSITION SPEED – R.P.M. |
|
|
INLET |
DISCHARGE |
|
|
2 2½ 3 |
6,300 5,040 4,200 |
5,155 4,125 3,435 |
|
4 5 6 |
3,150 2,520 2,100 |
2,575 2,060 1,720 |
|
7 8 10 |
1,800 1,575 1,260 |
1,470 1,290 1,030 |
|
12 14 16 |
1,050 900 785 |
860 735 645 |
|
18 20 22 |
700 630 570 |
570 515 470 |
|
24 |
525 |
430 |
|
PITCH LINE VELOCITY |
INLET SILENCER |
DISCHARGE SILENCER |
|
BELOW TRANSITION |
||
|
ABOVE TRANSITION |
|
SIZE |
CAPACITY (Inlet CFM 14.7 psia & 70°F) |
|||||
|
INLET SILENCER |
DISCHARGE SILENCER |
|||||
|
4 PSIG |
6 PSIG |
8 PSIG |
10 PSIG |
15 PSIG |
||
|
1 1½ 2 |
30 70 120 |
35 80 140 |
40 85 150 |
40 90 160 |
40 95 165 |
45 105 185 |
|
2½ 3 3½ |
190 270 370 |
220 320 430 |
235 335 455 |
245 355 480 |
255 370 505 |
285 415 560 |
|
4 5 6 |
480 750 1,080 |
560 880 1,260 |
600 935 1,340 |
630 985 1,410 |
660 1,030 1,480 |
735 1,150 1,650 |
|
8 10 12 |
1,920 3,000 4,300 |
2,250 3,520 5,070 |
2,390 3,730 5,370 |
2,510 3,930 5,660 |
2,630 4,110 5,920 |
2,940 4,590 6,600 |
|
14 16 18 |
5,900 7,700 9,700 |
6,890 9,000 11,400 |
7,310 9,550 12,100 |
7,700 10,000 12,700 |
8,060 10,500 13,300 |
8,990 11,800 14,900 |
|
20 22 24 |
12,000 14,500 17,300 |
14,000 17,000 20,200 |
14,900 18,100 21,500 |
15,700 19,000 22,600 |
16,400 19,900 23,700 |
18,400 22,200 26,400 |
|
26 28 30 |
20,300 23,500 27,000 |
23,800 27,600 31,700 |
25,200 29,300 33,600 |
26,600 30,800 35,400 |
27,800 32,200 37,000 |
31,000 36,000 41,300 |
|
EST. TEMP |
70°F |
115°F |
140°F |
165°F |
190°F |
240°F |
|
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Made In
USA
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