Vacuum oven · Calibration procedure
Vacuum gauge check
Compares the oven's vacuum gauge with a calibrated reference vacuum gauge at several pressures.
PURPOSE
Why this is checked
Many LOD methods state a maximum pressure. The oven gauge must read correctly so you know that pressure has been reached.
YOU WILL NEED
Standards & tools
- Calibrated reference digital vacuum gauge, traceable to national standards
BEFORE YOU START
Prerequisites
- Reference gauge connected to the chamber through a spare port or tee
- Door gasket clean
PROCEDURE
Step by step
- 1Close the door and evacuate the chamber.
- 2Use the valves to hold the chamber at several pressures (for example about 10, 50 and 100 mbar).
- 3Record the oven gauge and the reference gauge at each point once stable.
- 4Release the vacuum slowly.
RECORD
Example observation table
| Reference (mbar) | Oven gauge (mbar) | Difference (mbar) |
|---|---|---|
| 10 | 11 | +1 |
| 50 | 52 | +2 |
| 100 | 98 | −2 |
CALCULATION
How to calculate the result
Difference = Oven gauge − Reference; % error = Difference ÷ Reference × 100
- At 50 mbar: 52 − 50 = +2 mbar
- % error = 2 ÷ 50 × 100 = 4%
ACCEPTANCE CRITERIA
Pass if
- Within the limit in your SOP (for example ±5 mbar or ±10% of reading, whichever applies).
IF IT FAILS
What to do
- Label the instrument 'Out of calibration' and stop using it.
- Investigate the cause and arrange adjustment or repair.
- Assess the impact on results generated since the last passing calibration.
- Repeat the full calibration before returning it to use.
MORE
Other Vacuum oven calibrations
In LimsPulse · Calibration Management
LimsPulse schedules this calibration, records the result against limits, and blocks the instrument everywhere if it fails or goes overdue.