The structural design of the Roots blower muffler aims to reduce airflow noise (typically 85-110dB (A)) while controlling pressure loss. The following is a detailed analysis of its core structural composition:
---
**1、 3D anatomical diagram of muffler**
```plaintext
[Inlet flange]
│
∝ -- Airflow direction
│
│ +---------------------------------------+
│ | Outer shell: 2mm carbon steel/1.5mm stainless steel|
│ | ├─────────────────────────┤
│ | | | Resistance silencing zone: expansion chamber+resonant cavity | → Targeting 63-500Hz low frequency
│ | | ┌───────┐ ┌────────┐ |
│ | | │ Conical baffle │ │ Helmholtz cavity │|
│ | | └───────┘ └────────┘ |
│ | ├─────────────────────────┤
│ | | Resistive silencing zone: sound-absorbing layer+micro perforated panel | → Processing 500-4kHz medium and high frequencies
│ | | ┌───────────────┐ |
│ | | │ 50mm glass wool+0.8mm perforated plate │|
│ | | └───────────────┘ |
│ | ├─────────────────────────┤
│ | | Drainage structure: inclined bottom plate+DN20 drain valve|
│ | └─────────────────────────┤
│ +---------------------------------------+
│
[Exhaust flange]
```
---
**2、 Detailed explanation of core functional modules**
**1. Resistance silencing unit (low-frequency control)**
-Expansion Room Design**
-Reflecting sound waves through a sudden change in cross-section (area ratio 3:1~5:1), with a sound attenuation of Δ L=10lg [1+0.25 (m-1/m) 2sin2kl]
-Typical structure: 2-3 stages in series, total length ≥ 1.5 times the diameter of the main pipe
-* * Resonance cavity design**
-Helmholtz resonator: for specific frequencies (such as 125Hz)
-Calculation formula: f=(c/2 π) √ (σ/(V × l)) (c=sound velocity, σ=neck area)
**2. Resistive silencing unit (medium high frequency control)**
-* * Acoustic layer structure**
|Material | Thickness | Noise Reduction Frequency Range | Temperature Resistance|
|---------------|---------|----------|----------|
|Ultra fine glass wool | 50-100mm | 500-4kHz | ≤ 300 ℃|
|Ceramic fiber cotton | 80-150mm | 250-3kHz | ≤ 800 ℃|
-Micro perforated board**
-Plate thickness 0.8-1.2mm, aperture 0.5-1mm, perforation rate 1-3
-Principle of acoustic impedance matching, effectively absorbing mid to high frequency noise
**3. Shell and auxiliary structure**
-Double layer shell design**
-Outer layer: Carbon steel spray coated/stainless steel (1.5-3mm)
-Inner layer: perforated plate (perforation rate 20-30)+damping layer
-* * Drainage system**
-5 ° inclined bottom plate+stainless steel drain net (anti clogging)
-High humidity environment can be equipped with power distribution heating drainage valve
---
**3、 Key performance parameters**
|Parameters | Typical Values | Test Standards|
|-----------------|-------------------------|------------------|
|Noise reduction level | 20-35dB (A) | GB/T 4760-1995|
|Pressure loss | ≤ 2 rated pressure of fan | JB/T 6891-2010|
|Airflow velocity | 10-15m/s (core channel) | ISO 5801|
|Fire rating | Grade A (GB 8624-2012) ||
---
**4、 Structural variation under special working conditions**
1. Explosion proof design**
-Thicken the shell to 6mm (carbon steel)/4mm (stainless steel)
-Anti static rock wool for sound absorption layer (surface resistance ≤ 10 Ω)
2. * * Food grade design**
-Full 304/316L stainless steel structure
-The sound-absorbing material complies with FDA 21 CFR 177.1520
3. High temperature design**
-Ceramic fiber cotton+heat-resistant steel lining (≤ 800 ℃)
-Thermal expansion compensation structure (expansion joint)
---
**5、 Selection matching formula**
1. * * Calculation of muffler length**
$$
L=\ frac {c} {4f} \ times n \ quad (c=sound velocity, f=target frequency, n=number of chambers)
$$
-Example: For 250Hz noise, the length of a single chamber is approximately 340/(4 × 250)=0.34m
2. Verification of Flow Area**
$$
A_ {Silencer} \ geq 1.2 \ times A_ {Pipe} \ quad (Control flow rate ≤ 15m/s)
$$
---
**6、 Maintenance and lifespan**
-* * Acoustic material replacement * *: Every 2-3 years (shortened to 1 year in humid environments)
-Perforated plate cleaning: Compressed air blowback every month (pressure ≤ 0.3MPa)
-* * Overall lifespan * *: Carbon steel shell 8-10 years, stainless steel over 15 years
---
**Structural optimization suggestions * *:
1. For pulse noise (such as exhaust silencing), add a Venturi diffusion section to reduce regenerative noise
When high-frequency noise is prominent, use multi-layer micro perforated boards with a spacing of 50-100mm
3. If you need CAD drawings or CFD flow field simulation, you can contact professional manufacturers for customized design
