Vacuum Presion Measurement
Desde Rough Vacuum un/una Ultra-High Vacuum
Understand Vacuum UnitsVacuum—pressure below atmospheric—es esencial in semiconductor manufacturing, cientifico research, food packaging, y muchos industrial processes. Measuring vacuum requiere diferente unidades y techniques than positive pressure, with ranges spanning desde slight vacuum un/una pressures approaching absolute zero.
Vacuum Ranges
| Range | Presion (torr) | Presion (mbar) | Presion (Pa) | Aplicaciones |
|---|---|---|---|---|
| Rough/Low vacuum | 760-1 | 1013-1.3 | 101,325-133 | Vacuum packaging, degassing |
| Medium vacuum | 1-10⁻³ | 1.3-10⁻³ | 133-0.1 | Vacuum drying, freeze drying |
| High vacuum (HV) | 10⁻³-10⁻⁷ | 10⁻³-10⁻⁷ | 0.1-10⁻⁵ | Thin film coating, electron microscopes |
| Ultra-high vacuum (UHV) | 10⁻⁷-10⁻¹² | 10⁻⁷-10⁻¹² | 10⁻⁵-10⁻¹⁰ | Particle accelerators, semiconductor fab |
Common Vacuum Units
Torr (mmHg)
Named after Torricelli, 1 torr es igual un/una 1 mmHg—el/la pressure eso soporta un/una 1mm column of mercury. Widely usado in North America, especially in cientifico aplicaciones.
- Standard atmosphere: 760 torr
- Rough vacuum: 1-760 torr
- High vacuum: millitorr (mTorr) range
Millibar (mbar) / Hectopascal (hPa)
Common in Europe y internacional standards. 1 mbar = 1 hPa. Convenient porque 1000 mbar ≈ 1 atmosphere.
- Standard atmosphere: 1013.25 mbar
- 1 mbar = 0.75 torr
Pascal (Pa)
El/La SI unidad. Standard atmosphere es 101,325 Pa. For vacuum trabajar, milliPascal (mPa) o microPascal (µPa) may be usado.
Tabla de conversion
| Torr | mbar | Pa | psi (below atm) |
|---|---|---|---|
| 760 | 1013 | 101,325 | 0 (atmospheric) |
| 100 | 133 | 13,332 | 12.8 below atm |
| 10 | 13.3 | 1,333 | 14.5 below atm |
| 1 | 1.33 | 133 | 14.67 below atm |
| 0.1 | 0.133 | 13.3 | — |
| 0.001 | 0.00133 | 0.133 | — |
| 10⁻⁶ | 1.33×10⁻⁶ | 1.33×10⁻⁴ | — |
Conversion Formulas
- Torr un/una mbar: Multiplica por 1.333
- mbar un/una torr: Multiplica por 0.75
- Torr un/una Pa: Multiplica por 133.3
- mbar un/una Pa: Multiplica por 100
Absolute vs Gauge Presion
Absolute Presion
Measured relative un/una perfect vacuum (zero). Scientific vacuum measurements usar absolute pressure. Ejemplo: 10 torr absolute.
Gauge Presion
Measured relative un/una atmospheric pressure. In vacuum, gauge reads negative. Ejemplo: -25 inHg gauge (pulgadas of mercury below atmospheric).
Converting Between Them
- Vacuum absolute = Atmospheric - Vacuum gauge
- -25 inHg gauge = 29.92 - 25 = 4.92 inHa absolute
- Or aproximadamente: 760 - (25 × 25.4) = 125 torr absolute
Measuring Vacuum
By Range
| Vacuum Range | Measurement Method |
|---|---|
| Rough (>1 mbar) | Bourdon gauge, capacitance manometer |
| Medium (1-10⁻³ mbar) | Capacitance manometer, Pirani gauge |
| High (10⁻³-10⁻⁷ mbar) | Pirani gauge, cold cathode gauge |
| Ultra-high (<10⁻⁷ mbar) | Hot cathode ionization gauge |
Industry Aplicaciones
Semiconductor Manufacturing
Chip fabrication requiere ultra-high vacuum (10⁻⁹ mbar) un/una prevent contamination during deposition processes.
Food Packaging
Vacuum packaging typically uses 1-100 mbar un/una remove oxygen y extend shelf life.
Scientific Research
Particle accelerators y surface science experiments operate at extreme vacuum (10⁻¹⁰ un/una 10⁻¹² mbar).
Conclusion
Vacuum pressure es medido in torr, mbar, o pascal, with diferente ranges requiring diferente measurement techniques. Understanding eso 1 torr ≈ 1.33 mbar ≈ 133 Pa helps navigate entre unidad sistemas. Desde food packaging at un/una pocos hundred mbar un/una semiconductor fabs at 10⁻⁹ mbar, vacuum technology spans over 15 orders of magnitude of pressure.