**Detailed explanation of intake muffler for Roots blower**
The intake muffler of Roots blower is mainly used to reduce the aerodynamic noise (85-110dB (A)) generated during the operation of the blower, while filtering impurities to protect the blower. The following is an analysis of its structure, principle, selection, and maintenance:
---
**1、 Core functions**
1. * * Noise Reduction * *: Reduce intake pulsation noise (main frequency 125-500Hz)
2. * * Filtration * *: Intercept particles ≥ 5 μ m (dust, insects, etc.)
3. * * Fire prevention * *: Metal structures prevent sparks from being inhaled (under conditions of flammable gases such as biogas)
---
**2、 Typical structural composition**
```plaintext
[Inlet flange]
│
∝ - Airflow direction →
│
│ +------------------------------+
│ | Shell: 2mm carbon steel/1.5mm stainless steel|
│ | ├─────────────────┤
│ | |: Metal filter screen (aperture 1-3mm) | → Coarse filtration
│ | ├─────────────────┤
│ | | Level 2: Resistance expansion chamber | → Reflected low-frequency noise
│ | | ┌──────────────┐ |
│ | | │ Cone shaped flow guide+resonant cavity │|
│ | | └──────────────┘ |
│ | ├─────────────────┤
│ | | Level 3: Resistive sound-absorbing layer | → Absorbs mid to high frequencies
│ | | ┌──────────────┐ |
│ | | │ 50mm glass wool+perforated board │|
│ | | └──────────────┘ |
│ | └─────────────────┤
│ +------------------------------+
│
[From air outlet to fan]
```
---
**3、 Key design parameters**
|* * Parameter * * | Standard Value/Range | Impact of Exceeding Standards|
|------------------|--------------------------|-------------------------|
|Filtration efficiency | ≥ 90 (5 μ m particles) | Three times faster rotor wear acceleration|
|Initial pressure loss | ≤ 150Pa (rated flow) | For every 100Pa increase, the air volume decreases by 5|
|Noise reduction level | 15~25dB (A) | Noise level at 1m>85dB needs to be upgraded|
|Flow area ratio | ≥ 1.5 times the inlet cross-sectional area | Flow velocity>15m/s Increased regenerative noise|
---
**4、 Selection matching method**
1. * * Traffic matching**
-Silencer diameter ≥ fan inlet diameter (e.g. DN150 inlet, choose DN150~DN200 silencer)
2. * * Stress verification**
-Calculate the total pressure loss of the system (muffler+pipeline+filter) to ensure that it is ≤ 10% of the allowable back pressure of the fan
3. * * Special Needs**
-* * Anti corrosion * *: 316L stainless steel shell+PTFE coated filter screen
-Explosion proof: Conductive structure (resistance ≤ 10 Ω)
---
**5、 Installation specifications**
1. * * Location requirements**
-Distance from fan inlet ≤ 1.5 times the pipe diameter (to reduce airflow disturbance)
-When installing vertically, a drainage valve (slope ≥ 5 °) should be installed
2. * * Connection method**
-Flange standard: PN10/DN series (with oil resistant rubber gasket)
-Soft connection: Install rubber shock absorber joint (length ≥ 10D)
---
**6、 Maintenance management**
|* * Project * * | Cycle/Standard | Operational Points|
|----------------|-------------------------|-------------------------|
|Filter cleaning | Pressure difference>300Pa or monthly | Compressed air blowback (≤ 0.3MPa)|
|Acoustic cotton replacement | Every 2 years (1 year in humid environment) | Check for clumping and mold growth|
|Shell inspection | Quarterly | Corrosion area>10 requires anti-corrosion treatment|
---
**7、 Common problem handling**
-Problem 1: Decreased noise reduction effect**
**Reason * *: Blockage of the filter leads to airflow distortion
**Solution: Clean the filter screen and check the differential pressure gauge
-Problem 2: Abnormal vibration**
**Reason * *: Internal baffle detachment or bracket loosening
**Solution: Shutdown inspection, welding reinforcement
-Problem 3: Poor drainage**
**Reason * *: Blockage or insufficient inclination of the drain valve
**Solution: unclog the valve body and adjust the installation angle
---
**8、 Recommended brands and prices**
|Brand * * | Model Example | Applicable Air Volume (m3/min) | Price (yuan) | Features|
|------------|---------------|------------------|----------|-----------------------|
|JG-IS15 | 5~20 | 3000~6000 | Economy type, cast iron shell|
|ZG-AF20 | 10~30 | 8000~15000 | Stainless steel structure, low resistance design|
|Donaldson | P181015 | 15~50 | 20000~40000 | Imported filter material, fireproof and explosion-proof|
---
**Summary * *:
The intake muffler of Roots blower is a key component for noise reduction and protection, and the selection should take into account the flow rate, pressure loss, and medium characteristics. For high humidity or corrosive environments, it is essential to choose stainless steel material and maintain it regularly. It is recommended to prioritize selecting mufflers that match the original fan to ensure performance.
