**Professional Technical Guide for Roots Blowers (Vacuum Pumps)**
1、 Working principle and characteristics
1. Vacuum generation mechanism:
-By reversing the rotation of two three bladed rotors, a volume change is formed
-No internal compression design, maximum vacuum degree can reach -80kPa (absolute pressure 20kPa)
-Pumping speed range: 1~400m3/min
2. Comparison with traditional vacuum pumps:
|Features | Roots vacuum pump | Liquid ring pump | Rotary vane pump|
|---------------------|------------------|------------------|----------------|
|Extreme vacuum (kPa) | -80~-30 | -95~-70 | -100~-90|
|Extraction efficiency | High (60~75) | Medium (40~50) | Low (30~40)|
|Dust resistance ability | ★★★★☆☆ | ★★☆☆☆☆ | ★☆☆☆☆☆☆|
2、 Core structure design
1. * * Key components * *:
-* * Rotor system * *:
-Gradual opening line (4 teeth/6 teeth combination)
-Dynamic gap 0.08~0.15mm (with temperature compensation)
-Sealing technology:
-Triple seal combination:
```mermaid
graph LR
A [Mechanical Seal] -->B [Maze Seal] -->C [Nitrogen Barrier Seal]
```
-Cooling system:
-Air cooled type (≤ -50kPa)
-Water cooled type (≤ -80kPa)
2. * * Material selection * *:
|Components | Conventional Materials | Corrosive Environment Materials|
|------------|----------------|-----------------|
|Shell | HT250 | 316L stainless steel|
|Rotor | 20CrMnTi | 2205 duplex steel|
|Bearings | SKF C3 grade | Ceramic bearings|
3、 Performance parameter calculation
1. * * Speed formula * *:
\[
S=\ lambda \ cdot V_ {th} \ cdot n \ quad (\ text {actual pumping speed})
\]
-λ: Volumetric efficiency (0.65~0.85)
-V<sub>th</sub>: Theoretical displacement (m3/rev)
-N: Speed (rpm)
2. * * Power Calculation * *:
\[
P = \frac{Q \cdot \Delta P}{6120 \cdot \eta} \cdot K
\]
-Q: Extraction volume (m3/min)
-Δ P: Differential pressure (kPa)
-η: Mechanical efficiency (0.6~0.75)
-K: Coefficient (1.1~1.3)
4、 Vacuum system construction plan
1. * * Single level system * *:
-Applicable: -30kPa~-50kPa
-Configuration: Roots pump+cyclone separator
-Typical applications: Vacuum conveying, central vacuuming
2. * * Multi level system * *:
-High vacuum solution:
```mermaid
graph LR
A [Front stage pump] -->B [Roots booster pump] -->C [Main Roots pump]
```
-Performance parameters:
|Combination method | Extreme vacuum | Pump speed retention rate|
|-------------------|---------------|------------|
|Roots+rotary blade | -95kPa | 85|
|Roots+dry screw | -100kPa | 92|
5、 Intelligent control system
1. Precise adjustment of vacuum degree:
-PID control (pressure fluctuation ± 0.5)
-Variable frequency range: 20~65Hz
-Quick response:<100ms
2. * * Protection System * *:
|Protection project | Trigger value | Response measures|
|----------------|----------------|--------------------|
|Overload | 110 rated current | Soft shutdown|
|High temperature | 95 ℃ (bearing) | Start up auxiliary cooling|
|Vacuum failure | -10kPa (alarm) | Switch to standby pump|
6、 Maintain management standards
1. * * Daily Inspection Checklist * *:
|Project | Standard Value | Testing Tool|
|-----------------|-----------------|-------------------|
|Oil level | Window 1/2~2/3 | Visual inspection|
|Vibration | ≤ 4.5mm/s | Vibration analyzer|
|Noise | ≤ 85dB (A) | Sound level meter (1m distance)|
2. * * Major Maintenance Standards * *:
-Radial runout of rotor: ≤ 0.02mm
-Gear backlash: 0.12~0.18mm
-Sealing surface roughness: Ra ≤ 0.8 μ m
7、 Industry application cases
1. * * Electronic Coating * *:
-Requirement: -80kPa ± 0.5
-Configuration:
-Magnetic levitation bearing Roots pump
-Molecular sieve trap
-Effect: Uniformity of film thickness ± 3nm
2. * * Food Packaging * *:
-Parameters: -60kPa, pumping speed 50m3/min
-Special Design:
-Food grade lubrication system
-Quick disassembly and cleaning structure
8、 Selection service process
1. * * Parameter Confirmation * *:
-Working vacuum degree
-Extraction rate curve
-Gas composition analysis
2. * * Scheme Validation * *:
-CFD flow field simulation
-1:1 testing platform verification
-72 hour continuous operation test
9、 Mainstream products in the market
|Brand | Series | Vacuum Range | Price Coefficient|
|------------|------------|---------------|----------|
|JGV series | -30~-70kPa | 1.0|
|Atlas | ZR series | -50~-85kPa | 2.5|
| | RUVAC | -60~-90kPa | 3.0 |
**Note * *: ATEX explosion-proof certified models (Ex d IIB T4) are required for hazardous environments. Suggest configuring an inlet filter (accuracy ≤ 5 μ m) to protect the pump body. For corrosive gases, material compatibility testing should be conducted in advance.
