05 applied noise control - university of kentucky
TRANSCRIPT
D. W. Herrin, Ph.D., P.E. University of Kentucky
Department of Mechanical Engineering
Applied Noise Control
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
2
1. Introduction 2. Noise Control at Source 3. Noise Control of Transmission Path 4. Protection at Receiver 5. Summary
Outline of Topics
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
3
Path Source
Receiver
Source Path Receiver
Introduction
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
4
1. Introduction 2. Noise Control at Source 3. Noise Control of Transmission Path 4. Protection at Receiver 5. Summary
Outline of Topics
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
5
Noisy Design
Quiet Design
Reduce Impact Forces
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
6
Noisy Design
Quiet Design
Application Cutting of Cardboard
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
7
Operate at low speed
Use large-diameter low-speed fan
Reduce Speed and Pressure
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
8
A 50% reduction in velocity may lower noise by 10-20 dB
Pressure reduction may lower noise
Reduce Flow Velocities and Pressures
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
9
One of the main sources of machinery
noise
Method: add counter weights or remove
some weights
Balance Rotating Parts
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
10
Noisy Design
Quiet Design
Reduce Flow Resistance
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
11
Noisy Design
Quiet Design
Design of Quiet Flow System
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Noisy Design
Quiet Design
Isolate Vibrating Elements in Machine
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Application Machinery Noise Reduction
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Noisy Design
Quiet Design
Reduce Radiating Area
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
15
Noisy Design
Quiet Design
Hoods and Protective Covers
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
16
Apply Damping Material
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Adding Coatings to a Plate
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Noisy Design
Quiet Design
Reduce Noise Leakage
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
19
Effect of Enclosure Sound Leaks
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
20
Quiet Design
Noisy Design
Avoid Flow Past Hollow Openings
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
21
Use plastic containers instead of containers made of heavy glass
Substitute rubber or plastic trash cans for noisy metal cans
Use wood or fiberboard cabinets instead of metal units
Select sliding or folding closet doors made of wood or laminate instead of metal doors
Replace small high-speed fans with larger, slower-moving units
Change usual procedure of operation
Tips for Controlling Noise
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
22
1. Introduction 2. Noise Control at Source 3. Noise Control of Transmission Path 4. Protection at Receiver 5. Summary
Outline of Topics
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
23
Closed-cell Foam is not
absorptive material
Open-cell Foam is
absorptive material
Absorptive Material Foam
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Absorptive Materials
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
25
Absorptive Materials
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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energyincident energy absorbedtcoefficien absorption =
Absorption Coefficient
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
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Ideal Case Anechoic Room
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
28
Room Treatment
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
29
Ceiling Treatment
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
30
Pipe Lagging
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
31
Free Field 6 dB SPL decrease for each doubling of distance
Separate Source and Receiver
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
32
Sound Barriers
Noisy Design Quiet
Design
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
33
SPL for Different Barriers
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
34
Noisy Design
Quiet Design
Application Auto Plant Barrier
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
35
Application Road Barrier
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
36
Partial Enclosures
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
37
Complete Enclosure
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
38
Untreated Treated
Enclosure with Ventilation Openings
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
39
SPL Comparison of Different Openings
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
40
Enclosure
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
41
Noisy
Quiet
Install Muffler or Silencer
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
42
Industrial Silencers
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
43
Application Muffler for a Large Engine
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
44
Application Fan Inlet Muffler
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
45
Flexible Couplings
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
46
Vibration Isolators
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
47
Application Electric Motor
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
48
Application Compressor
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
49
Noisy Layout
Quiet Layout
Modify Equipment Layout
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
50
1. Introduction 2. Noise Control at Source 3. Noise Control of Transmission Path 4. Protection at Receiver 5. Summary
Outline of Topics
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
51
Ear Protection Devices
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
52
Other Approaches
Booth
Hearing Conservation Programs and Education
Exposure Control
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
53
1. Introduction 2. Noise Control at Source 3. Noise Control of Transmission Path 4. Protection at Receiver 5. Summary
Outline of Topics
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
54
Move the machinery to a new location, more distant from the area where quiet is required
Provide vibration isolation to reduce the radiation from surface on which the machinery is mounted
Use a partial enclosure around the machine Use a complete enclosure around the machine, or use a booth to
house the operator when it is impractical to quiet the machine
Reduce the leakage paths that permit noise to leak through openings in the enclosure
Reduce impact forces
Summary
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
55
Apply vibration-damping materials to the housing of the machine Insert flexible connectors between the machine and conduit,
cable, piping, or ductwork connected to it
Use an inertia block, where appropriate Reduce or modify surfaces that radiate noise
Reduce resonance effects in mechanical and acoustical systems
Use sound-absorptive material Modify or replace noisy parts (gears, bearings etc.)
Reduce unbalance in rotating systems
Summary
Applied Noise Control
Noise and Vibration Short Course
Dept. of Mechanical Engineering University of Kentucky
56
Use ducts lined with sound-absorptive material Use wrapping or lagging on pipes or ducts to increase
their sound insulation
Reduce or eliminate aerodynamically generated noise
Summary