You’re comparing two vacuum pumps online. One lists its performance in mbar, another in torr, and a third in microns. Suddenly, you’re not sure if “0.01 mbar” is better or worse than “10 microns.” Sound familiar? Let’s decode the chaos behind vacuum measurement units so you can confidently evaluate pump specs.
The 4 Key Units – And Why Regions Disagree
Vacuum pressure is measured using four main units, each with its own history and regional stronghold:
- Torr (USA’s Favorite)
- Origin: Named after Evangelista Torricelli, who invented the mercury barometer in 1643.
- How it works: 1 Torr ≈ 1 mm of mercury (Hg) pressure.
- Fun fact: The unit was renamed “Torr” in the 1970s to honor Torricelli.
- Millibar (Europe’s Standard)
- Origin: Derived from the bar unit, introduced by Norwegian meteorologist Vilhelm Bjerknes for weather forecasting.
- Conversion: 1 mbar = 0.75 Torr = 100 Pascals.
- Why it matters: Dominates industrial specs in Germany, France, and neighboring countries.
- Pascal (Asia’s Rising Star)
- Origin: Honors French physicist Blaise Pascal, who proved atmospheric pressure decreases with altitude.
- Conversion: 1 Pa = 0.0075 Torr = 7.5 microns.
- Real-world use: Common in Japanese and Chinese lab equipment manuals.
- Micron (Industry Niche)
- Origin: A fraction of Torr (1 micron = 0.001 Torr).
- Where you’ll see it: Semiconductor manufacturing, HVAC systems.
- Watch out: 1 micron ≠ 1 micrometer! It’s specifically a pressure unit.
The Cheat Sheet Every Engineer Needs
| Unit | Torr | mbar | Pascal (Pa) | Micron |
|---|---|---|---|---|
| 1 Torr | 1 | 1.33 | 133.3 | 1000 |
| 1 mbar | 0.75 | 1 | 100 | 750 |
| 1 Pa | 0.0075 | 0.01 | 1 | 7.5 |
| 1 Micron | 0.001 | 0.0013 | 0.133 | 1 |
Why Unit Choice Matters for Pump Selection
A pump advertised as achieving “2 Pa” (0.015 Torr) might seem superior to one rated at “15 microns” – until you realize they’re the same vacuum level. Here’s how to avoid confusion:
- Rough vacuum (e.g., packaging): 1,000 to 1 mbar (750 to 0.75 Torr).
- Medium vacuum (e.g., freeze drying): 1 mbar to 0.001 mbar (0.75 to 0.00075 Torr).
- High vacuum (e.g., space simulation): Below 0.001 mbar (0.00075 Torr).
Pro tip: When comparing pumps:
- Convert all specs to one unit using the table above.
- Ignore “partial ultimate pressure” claims – they’re marketing fluff.
- Focus on working pressure range, not just ultimate pressure.
The Hidden Trap in Pump Spec Sheets
A manufacturer claims their single-stage pump reaches “150 microns.” Sounds impressive, right? Not quite:
- 150 microns = 0.15 Torr = 20 Pa = 0.2 mbar
- This is still a rough vacuum – achievable by most basic pumps.
Meanwhile, a dual-stage pump hitting “15 microns” (0.015 Torr/2 Pa) delivers 10x better vacuum but might cost 3x more. Knowing units helps you spot overpriced underperformers.
How to Never Get Lost Again
- Bookmark the conversion table – Print it and tape it to your workbench.
- Ask for dual-unit specs: Reputable suppliers list pressure in both mbar and Torr.
- Use free apps: Tools like Vacuum Unit Converter instantly translate units on your phone.
- Coolink: TOP 3 Global HVAC Vacuum Pump Manufacturer
- Elitevak: Quality Industrial Vacuum Pump Supplier from China
Coolink, a TOP 3 Global HVAC Vacuum Pump Manufacturer & Quality Industrial Vacuum Pump Supplier from China
