Leak Testing – Destructive and Non Destructive Options
A Practical Review of Destructive and Non Destructive Leak Testing
Leaking MAP packages are a major problem for all food packers. They trigger several consequences and most of them land back with the packaging company:
- inedible product delivered to the customer
- product with reduced shelf life
- increased food waste
- increased packaging waste
- significant financial penalties per pack
- damage to brand and customer reputation
- damage to packer reputation
- loss of contracts
Even a hole as small as 50 micron can introduce disastrous levels of O2 to the headspace within 3 days. Of coursesuch small holes can be difficult to detect, but not impossible. We have several excellent solutions from the Dansensor range to help you cut your leaker rate to an all time low.
For example, putting a non destructive Dansensor LeakMatic II at the end of the production line has helped one of our customers bring their leak rate down from 17% to just over 2%. A dramatic reduction with significant financial and reputations benefits.
Leak Detection Methods
Hand Squeeze The Pack in a Bowl of Water
This is a very popular test method and works well when the holes are large and the leaks obvious. The bag is simply held under water by hand and squeezed as hard as possible. A stream of bubbles reveals the position of any hole.
In many instances this method will not identify leaks from small holes. These only show when the packaging is placed under a much higher pressure than can be generated by hand – and particularly hands that are cold and tired by frequent testing. Very small holes are more easily identified using the vacuum water test chamber.
Bags that show no bubbles in the water bowl test are often wiped down and sent out. The test would be regarded as non-destructive. However, if there is an undetected micro leak, water will ingress into the hole and there is a high probability that bath water will contaminate the pack, turning it, in effect, into a destructive test.
Vacuum Water Test Chamber
The test pack is immersed in the vacuum tank, the lid closed and a vacuum applied. As a result, the pack inflates from the gas inside and the pressure differential forces gas out through holes and/or seal faults.
Even very small holes can be detected. The stream of bubbles identifies the exact position of the fault and when present in several packs, it helps to determine which sealing jaw is underperforming. Being able to direct an engineer to the exact location of the problem, helps reduce line down time.
If no bubbles show, then the pack can be regarded as having no leaks, can be confidently wiped down and sent out. A non-destructive test. Where packs show leaks, the test is destructive and they must be discarded.
Dansensor Leak Testers
Reliable non-destructive manual testing of single packs. Repeatedly capable of detecting leaks, as small as 50 microns (µm). A vacuum operation with the detection of trace gas CO2.
LeakPointer II E2
Large volume, manual leak detector for products already packed inside transit cases, or trays. Reliable non-destructive testing of multiple packs. Creates a vacuum and detects the release of trace gas CO2.
Fully automated, end of line, non-destructive leak detection system for crates and multipacks. Extremely sensitive to trace gas CO2. Microleak detection.
A destructive test for quantifiably determining the strength of a pack seal. Ideal for ensuring that jaws and heat sealers are performing optimally, particularly when changing film materials.