Pressure Decay Testing
Food manufacturers incorporate stringent quality control measures to check for the seal integrity of their products to ensure a maximum shelf life. Quality control personnel will do batch leak testing and preferably, record the data for traceability. Of the many existing food packaging testing methods, the bubble leak detector and the pressure decay testing method of vacuum decay leak detector are the two most widely known techniques and used in the industry.
The bubble leak detector tests seal integrity by submerging the package underwater in water-filled transparent acrylic case and place in under vacuum. It is one of the simplest packaging leak testers in the market which demonstrate the leaks by bubbles arising from the location of leak. The tested packages have to be discarded after each test and the results are proven to be unreliable due to its high dependency on the operators.
Vacuum decay leak detector works by measuring the pressure decay using the highly sensitive differential pressure transducer. It creates the vacuum around the package and leaks are determine by the change in vacuum decay. This technique provides quantifiable leak data which can be stored and retrieved. The packages can also be returned to the production line, provided it passes the preset leak condition.
Both of these methods have their advantages and disadvantages. Choosing which systems to be used depends on your testing requirements and objectives
- Complexities and Labor cost
The bubble leak testers heavily rely on the operator to judge whether the packages leak. As the test determination is visually done, anyone can do it with just a simple instruction. However, this test is subjective, and operator fatigue can affect the quality of tests over a long period. Bubble leak detection is not suitable if you are testing hundreds or thousands of packages per day.
Vacuum decay leak testers offer a fast, accurate and reliable testing of seal integrity in less than 15 seconds. This semi-automated system offers quantitative leak data that is not reliant on the operators. Therefore, it is more accurate and reliable. It needs the operator to know how to setup the test procedure to ensure that the systems can accurately detect for leaks based on your testing requirement.
2. Waste
If you are testing high-value products such as milk powder, it is highly advisable to use a non-destructive vacuum decay leak tester. The bubble leak detector is destructive, which means products cannot be returned to the production line, even if it passes the test. Therefore, it is not an efficient method and incurs huge losses when testing high-value products such as milk powder.
3. Data storage capability
Vacuum decay testers are the preferred option if you are looking for a system with data storage capability as the leak results are quantifiable. The results can be retrieved by operators via USB or Ethernet for quality traceability. Underwater bubble leak testers do not provide this feature as the operators have to manually record the data.
4. Locate leaks
Vacuum decay leak tester can provide fast and accurate results of package leaks, however, it cannot be used to determine the exact leak location. In the bubble leak testing systems, it is possible to locate the leak in the packages visually.
Ideally, it is advisable to use a combination of both systems for packaging leak detection. Vacuum decay leak testers can be used as primary system for quick and accurate testing in the production line. The packages that fail the test can be further tester with the bubble leak tester to figure out the exact leak location. Based on the leak location, operators can make adjustments to the equipment to correct the problem.