Leak / Vacuum Tester
Checks that packs and containers are sealed, by pulling a vacuum around them and looking for dye ingress, bubbles or a rise in chamber pressure. Covers simple blister leak tests and deterministic vacuum-decay CCI testing.
- Pharmaceutical
- Medical devices
- Food packaging
- Nutraceutical
How Leak tester works
A pressure difference across a leak drives gas or liquid through it. In dye ingress the coloured liquid is pulled in when the vacuum is released. In vacuum decay the chamber is evacuated and isolated; gas or vapour escaping from a leaking pack makes the chamber pressure rise, which is measured and compared with a limit set using known leak standards.
The path of a sample
- 01
Load
The pack or container is placed in the test chamber (submerged in dye for a dye test).
- 02
Evacuate
A vacuum pump reduces the chamber pressure to the set level.
- 03
Hold / isolate
The vacuum is held for a set time; in vacuum decay the chamber is isolated from the pump.
- 04
Measure
Pressure rise is measured (vacuum decay) or bubbles are watched (bubble test).
- 05
Release
The vacuum is released; for dye tests the atmospheric pressure pushes dye into any leak.
- 06
Judge
Packs are inspected for dye, or the pressure result is compared with the pass/fail limit.
Main parts and what they do
Test chamber
Transparent desiccator-type vessel for dye/bubble tests, or a close-fitting metal chamber for vacuum decay.
Vacuum pump
Creates the vacuum in the chamber.
Vacuum gauge / pressure transducer
Shows vacuum level; vacuum decay testers use sensitive absolute and differential transducers.
Valves and timer
Control evacuation, hold and release and the test time.
Controller and software
Stores test recipes and limits, records results and audit trail (vacuum decay).
Hold-down plate
Keeps blister strips under the dye surface.
Terms every analyst should know
Deterministic method
Measures a physical event with a predictable result and objective data, e.g. vacuum decay or laser headspace analysis.
Probabilistic method
Detection depends on chance events and inspection, e.g. dye ingress or microbial challenge.
Positive control
A container with a known, calibrated defect (e.g. a laser-drilled micro-hole) used to prove the test detects leaks of that size.
Maximum allowable leakage limit
The largest leak a pack can have without risk to product quality or sterility; the test must be able to detect it.
Methylene blue test
A common in-house blister test: strips are held under a dilute methylene blue solution at a vacuum, then checked for blue penetration.
Keep every Leak tester in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.