Absorptive Silencers
5
1 0 R o t a r y P o s i t i v e B l o w e r S i l e n c e r s 3.1 A b s o r p t i v e S i l e n c e r s 1 2 3 4 5 6 7 8 3.1 S e e p a g e s 1 . 1 – 1 . 3 f o r o r d e r i n g i n f o r m a t i o n | w w w . u n i v e r s a l s i l e n c e r . c o m 9 U5 Series (page 3.2) Highly efficient straight-through silencer available in pipe sizes ¹⁄₂"–6". Attenuation characteristics equivalent to SU5 Series. U2 Series (page 3.3) Moderately efficient straight-through silencer available in pipe sizes 5"–30". For better performance, use SU3, SU4, SU5, or U5 Series. SU5 Series (page 3.4–3.5) Highest efficiency full flow annular type silencer. Available in pipe sizes 4"–60". Larger sizes available based on application. SU4 Series (page 3.4–3.5) Annular type silencer with performance one grade below the SU5 Series. Available in pipe sizes 8"–60". Larger sizes available based on application. SU3 Series (page 3.4–3.5) Annular type silencer with performance one grade below the SU4 Series. Available in pipe sizes 8"–60" and larger. Sizing Information, Pressure Drop Data The flow area through the silencer must be sufficient to accommodate the maximum flow without imposing excessive pressure drop. The following instructions enable the selection of the proper silencer size and determination of actual pressure drop. These instructions assume air as the flowing gas. For other gases, density and other corrections may be necessary—contact Universal Silencer for assistance. Data required: air flow rate (actual CFM) temperature (°F) pressure (psig) maximum pressure drop (inches of water) 2 1 Det ermine max imu m vel oci ty . V = air or gas velocity, ft/min (see note 1) P = maximum pressure drop, inches of water c = silencer pressure drop co efficient (see Table 1) T = air temper ature, °F (see no te 2) P = opera ting pressu re, psig (If at atmospheric pressure, pressure ratio is unity and may be omitted from equation. If P exceeds 15 psig, contact Universal Silencer for recommendations.) 2 Determine flow area required. A = flow area required, ft 2 Q = air flow rate (actual CFM) 3 From T able 2, sel ect siz e with flow a rea equal to or greater than that calculated. 4 Dete rmin e ac tual gas velo city i n ft/ min. A = flow area from Table 2 5 Determine ac tua l pressure drop. c =silencer pressure drop coefficient (see Table 1) V 4005 14.7 P 14.7 P c T 460 Q V A 530 T 460 P 14.7 14.7 V actual 4005 P c U5, U2 SU5 SU3, SU4 .25 .75 .85 Silencer Series Pressure Drop Coefficient (C) Pressure Drop Coefficients 1 0.0014 0.0031 0.0055 0.012 0.022 0.034 0.049 0.067 0.087 0.136 0.196 0.349 0.55 0.79 1.07 1.4 1.8 2.2 ¹⁄₂ ³⁄₄ 1 1¹⁄₂ 2 2¹⁄₂ 3 3¹⁄₂ 4 5 6 8 10 12 14 16 18 20 2.6 3.1 3.7 4.3 4.9 5.6 6.3 7.1 7.9 8.7 9.6 10.6 11.5 12.6 15.9 19.6 23.8 28.3 22 24 26 28 30 32 34 36 38 40 42 44 46 48 54 60 66 72 Flow Area (ft 2 ) Diameter Size (in) Flow Area (ft 2 ) Diameter Size (in) Flow Area Size 2 Notes 1 Since self noise and aerodynamic noise generation increase with velocity, absorptive silencers are usually sized for 4,000–8,000 ft/min. In no case should the velocity exceed 15,000 ft/min, regardless of pressure drop allowed. 2 Typical attenuation curves indicate the characteristics of the silencer series and are neither a minimum nor a guarantee for an individual silencer. Individual silencer performance can be affected by sound source characteristics including pure tones, flow velocity, adjacent piping, and temperature. The absorptive type silencer is the classic dissipative design, deriving its noise control properties from the basic fact that noise energy is effectively “absorbed” by various types of fibrous packing materials. More technically , as sound waves pass through the spaces between the tightly-packed small- diameter fibers of the absorptive material, the resulting viscous friction dissipates the sound energy as small amounts of heat. General Information Absorptive Silencers T 460 530 14.7 P 14.7 Actual CFM (Standard CFM) Q A V actual Absorptive silencers are very effective on high frequency noise (500–8,000 Hz). At frequencies above and below this range, attenuation performance progressively diminishes. Since noise is absorbed by the packing media, absorptive silencers do not rely on internal baffles, tubes or other restrictive devices to achieve noise reduction. Consequently, absorptive silencers generally employ “straight-through” or similar internal designs which impose very little air flow restriction.
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Silenciadores de absorcion
Transcript of Absorptive Silencers
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9U5 Series (page 3.2) Highly efficient straight-through silenceravailable in pipe sizes "6". Attenuationcharacteristics equivalent to SU5 Series.
U2 Series (page 3.3) Moderately efficient straight-throughsilencer available in pipe sizes 5"30". Forbetter performance, use SU3, SU4, SU5, orU5 Series.
SU5 Series (page 3.43.5) Highest efficiency full flow annular typesilencer. Available in pipe sizes 4"60".Larger sizes available based on application.
SU4 Series (page 3.43.5) Annular type silencer with performance onegrade below the SU5 Series. Available inpipe sizes 8"60". Larger sizes availablebased on application.
SU3 Series (page 3.43.5) Annular type silencer with performance onegrade below the SU4 Series. Available inpipe sizes 8"60" and larger.
Sizing Information, Pressure Drop DataThe flow area through the silencer must besufficient to accommodate the maximum flowwithout imposing excessive pressure drop.The following instructions enable theselection of the proper silencer size anddetermination of actual pressure drop. Theseinstructions assume air as the flowing gas.For other gases, density and other correctionsmay be necessarycontact UniversalSilencer for assistance.
Data required:air flow rate (actual CFM)temperature (F)pressure (psig)maximum pressure drop (inches of water)
2
1 Determine maximum velocity.
V = air or gas velocity, ft/min (see note 1)
P = maximum pressure drop, inches of water
c = silencer pressure drop coefficient(see Table 1)
T = air temperature, F (see note 2)P = operating pressure, psig
(If at atmospheric pressure,pressure ratio is unity and may beomitted from equation. If Pexceeds 15 psig, contactUniversal Silencer forrecommendations.)
2 Determine flow area required.
A = flow area required, ft2
Q = air flow rate (actual CFM)
3 From Table 2, select size with flow areaequal to or greater than that calculated.
4 Determine actual gas velocity in ft/min.
A = flow area from Table 2
5 Determine actual pressure drop.
c =silencer pressure drop coefficient (see Table 1)
V 4005 14.7P 14.7 Pc T 460
QVA
530T 460 P 14.714.7V actual4005P c
U5, U2SU5SU3, SU4
.25
.75
.85
Silencer Series Pressure DropCoefficient (C)
Pressure Drop Coefficients1
0.00140.00310.00550.0120.0220.0340.0490.0670.0870.1360.1960.3490.550.791.071.41.82.2
1122334568
101214161820
2.63.13.74.34.95.66.37.17.98.79.6
10.611.512.615.919.623.828.3
222426283032343638404244464854606672
Flow Area(ft2)
DiameterSize (in)
Flow Area(ft2)
DiameterSize (in)
Flow Area Size2
Notes1 Since self noise and aerodynamic noise
generation increase with velocity,absorptive silencers are usually sized for4,0008,000 ft/min. In no case shouldthe velocity exceed 15,000 ft/min,regardless of pressure drop allowed.
2 Typical attenuation curves indicate thecharacteristics of the silencer series andare neither a minimum nor a guarantee foran individual silencer. Individual silencerperformance can be affected by soundsource characteristics including puretones, flow velocity, adjacent piping, andtemperature.
The absorptive type silencer is the classic dissipative design, deriving its noise control properties from the basic fact that noiseenergy is effectively absorbed by varioustypes of fibrous packing materials. Moretechnically, as sound waves pass throughthe spaces between the tightly-packed small-diameter fibers of the absorptive material,the resulting viscous friction dissipates thesound energy as small amounts of heat.
GeneralInformation
Absorptive Silencers
T 46053014.7
P 14.7Actual CFM (Standard CFM)
QAV actual
Absorptive silencers are very effective on highfrequency noise (5008,000 Hz). At frequenciesabove and below this range, attenuationperformance progressively diminishes.
Since noise is absorbed by the packingmedia, absorptive silencers do not rely oninternal baffles, tubes or other restrictivedevices to achieve noise reduction.Consequently, absorptive silencers generally
employ straight-through or similar internal designs which impose very little air flow restriction.
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PartModel
U5 SeriesStraight-ThroughAbsorptive Silencer
The U5 Series is a premium, straight-through, absorptive silencer. It providesexcellent noise attenuation due to its veryhigh length to diameter ratio. It is especiallywell suited for inlet service on small rotarypositive or centrifugal blowers or thedischarge of vacuum pumps. Mild steelconstruction with enamel paint.
Common Applicationsrotary positive/centrifugal blowersvacuum pump dischargeair valves and cylinderssmall low-pressure ventshigh frequency noise sources
U5-U5-U5-1U5-1U5-1U5-2U5-2U5-3U5-4U5-5U5-6
11-150-AA11-170-AA11-101-AA11-121-AA11-115-AA11-102-AA11-125-AA11-103-AA11-104-AA11-105-AA11-106-AA
111223456
333345668
1012
811141619263336485763
33
811141618253235485157
23346
1015204060
100
P D L N H Weight
4045
63 125 250 500 1K 2K 4K 8K
105
15
0
20253035
Octave Band Center Frequency, Hz
Attenuation, dB
Typical Attenuation Curve
NoteU5 series standard paint and acousticalpacking are suitable for 325F.
N N
P P
HL
D
1. Sizes " through 1" are constructed with one-piece tapped heads.The tapped opening is approximately flush with the end on the shell.
2. Sizes " through 4": female NPT pipe connections.3. Sizes 5" and 6": 125#/150# ANSI drilled flanges.
Absorptive Material
Straight-Through Absorptive Silencer
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U2 SeriesStraight-Through
Absorptive Silencer
The U2 Series is an economical straight-though silencer for applications requiringlower-degree noise attenuation. It isfundamentally similar to the U5 Series, buthas lesser attenuation due to its relativelylow length to diameter ratio. Mild steelconstruction, primer-coated exterior.
Common Applicationsintermediate size rotary positive blower inletcentrifugal blower inlet or discharge intermediate size dry vacuum pump dischargegas turbine inlethigh-speed centrifugal compressor inlethigh frequency noise sources
PartModel
U2-5U2-6U2-8U2-10U2-12U2-14U2-16U2-18U2-20U2-22U2-24U2-30
10-105-AA10-106-AA10-108-AA10-110-AA10-112-AA10-114-AA10-116-AA10-118-AA10-120-AA10-122-AA10-124-AA10-126-AA
568
101214161820222430
101214161820222426283036
364053657789
101113128140152189
333333334444
30344658708294
106119131143180
4570
105160220340440530700820
1,0701,940
P D L N H Weight
4045
63 125 250 500 1K 2K 4K 8K
105
15
0
20253035
Octave Band Center Frequency, Hz
Attenuation, dB
Typical Attenuation Curve
Note:U2 series standard paint and acousticalpacking are suitable for 325F.
N NHL
DP
All sizes are furnished with flanged connectionsto match 125#/150# ANSI drilling.
P
Absorptive Material
Straight-Through Absorptive Silencer
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SU SeriesAnnular FlowAbsorptive Silencer
4045
63 125 250 500 1K 2K 4K 8K
105
15
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20253035
Octave Band Center Frequency, Hz
Attenuation, dB
Typical Attenuation Curve
4045
63 125 250 500 1K 2K 4K 8K
105
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20253035
Octave Band Center Frequency, Hz
Attenuation, dB
Typical Attenuation Curve
SU5 SeriesThe SU5 Series is our highest gradestandard absorptive silencer. Its designconsists of two concentric perforatedcylinders lined with acoustical pack, formingan annular flow path. This design featuresfull blocked-line-of-sight, while providingfull flow area for low resistance. Mild steelconstruction, primer-coated exterior.
SU4 SeriesThe SU4 Series provides lower attenuation, ranking just below the SU5Series. The design of this unit features abullet centered in the flow tube to provideannular flow path and partial blocked-line-of-sight. Pressure drop is only slightlygreater than the SU5. Mild steelconstruction, primer-coated exterior.
4045
63 125 250 500 1K 2K 4K 8K
105
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20253035
Octave Band Center Frequency, Hz
Attenuation, dB
Typical Attenuation Curve
SU3 SeriesThe SU3 Series is the most economical ofUniversal Silencers three grades of annulardesign silencers. Its design is nearlyidentical to the SU4, including annular flowpath and partial blocked-line-of-sight.Pressure drop coefficient is the same as forthe SU4 Series. Mild steel construction,primer-coated exterior.
Common Applicationsinlet and discharge of high-speed, low-pressure centrifugal compressorsand blowers (discharge P < 15 psig)industrial fan inlet and dischargehigh-pressure centrifugal compressors inletgas turbine inletdry vacuum pump dischargesome low-pressure vents (< 15 psig)high-frequency noise sourcesinlet of turbocharged reciprocating engines
12" size and smaller24" size and larger
Note:SU Series standard paint and acousticalpacking are suitable for 325F.
N NHL
DP
All sizes furnished with flanged connections to match 125#/150# ANSI drilling.
P
Absorptive Material
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SU SeriesAnnular Flow
Absorptive Silencer
Model Part P D L N H Weight
SU5-4SU5-5SU5-6SU5-8SU5-10SU5-12SU5-14SU5-16SU5-18SU5-20SU5-22SU5-24SU5-26SU5-28SU5-30SU5-32SU5-34SU5-36SU5-42SU5-48SU5-54SU5-60SU4-8SU4-10SU4-12SU4-14SU4-16SU4-18SU4-20SU4-22SU4-24SU4-30SU4-36SU4-42SU4-48SU4-54SU4-60SU3-8SU3-10SU3-12SU3-14SU3-16SU3-18SU3-20SU3-22SU3-24SU3-26SU3-28SU3-30SU3-32SU3-34SU3-36SU3-42SU3-48SU3-54SU3-60
14-104-AA14-105-AA14-106-AA14-108-AA14-110-AA14-112-AA14-114-AA14-116-AA14-118-AA14-120-AA14-122-AA14-124-AA14-126-AA14-128-AA14-130-AA14-132-AA14-134-AA14-136-AA14-142-AA14-148-AA14-154-AA14-160-AA13-108-AA13-110-AA13-112-AA13-114-AA13-116-AA13-118-AA13-120-AA13-122-AA13-124-AA13-130-AA13-136-AA13-142-AA13-148-AA13-154-AA13-160-AA12-108-AA12-110-AA12-112-AA12-114-AA12-116-AA12-118-AA12-120-AA12-122-AA12-124-AA12-126-AA12-128-AA12-130-AA12-132-AA12-134-AA12-136-AA12-142-AA12-148-AA12-154-AA12-160-AA
4568
1012141618202224262830323436424854608
10121416182022243036424854608
101214161820222426283032343642485460
1012121820242628303636424248485460606678849014161820222426283036424854606614161820222426283030363636424248546066
21262636
4453
616874788991
102104115128136145170186198210333547515963
737385
108122137
161178
192313539394747
49555561
6362687580838996
108
33333333344444466666663333334444466663333334444444446666
1520202937465461676980829395
10611612413315817518619826284044525664647699
11312514916618024283232404040464652545359667171778496
305560
120195290390500650950
1,0801,4001,5802,2002,6003,1503,6004,5006,2008,200
10,30012,500
90120180240320370490530720
1,3402,0203,2004,1005,4007,300
85120155200270290350420500680830890
1,1201,3601,4901,9202,6003,3004,430
SU5
SU4
SU3
