Correlating Gas Leakage Rates to Fluid Ingress in Sensor Seals
Correlating gas leakage rates to liquid ingress requires deriving equivalent pore radius to confirm capillary entry pressure exceeds target hydrostatic head.
Vacuum Decay Testing
Leak Detection
Non-destructive measurement of pressure changes within a vacuum chamber determines the integrity of a sealed package or container. This vacuum decay testing method relies on placing the test specimen in a tightly fitted chamber and evacuating the surrounding air. If a leak exists, the contents of the package escape into the chamber and cause the pressure to rise.
Testing Cycle
Sequence begins with an evacuation phase where a pump removes the air from the test volume. After a short stabilization period, the system isolates the chamber and monitors the pressure over a fixed duration. A high-precision transducer records the rate of change and compares it to a pre-set limit derived from a master non-leaking part.
Volume Influence
Accuracy depends on the dead volume, which is the empty space between the specimen and the chamber walls. Minimizing this space ensures that even a tiny amount of escaping gas produces a measurable rise in pressure. Custom-machined tooling is used to match the shape of the product and maximize the detection signal.
Detection Limit
Liquid contents can mask leaks by freezing or plugging the hole when exposed to the vacuum. This phenomenon occurs because the drop in pressure causes rapid evaporation which chills the liquid until it solidifies. The test is most effective for dry products or for containers where the headspace contains enough gas to provide a consistent pressure signal.