Proper leak detection equipment is essential to ensuring the safety and value of the food we produce and consume. Essentially a means of quality control, leak detectors inspect the integrity of many different types of packages, including: three sided pouches, stand-up pouches, side gusset pouches, bottom seal pouches, rigid trays with lidding material flushed with modified atmosphere packaging (MAP) and any other food packaging.
1. The necessity of leak detection equipment
Packages should be absolutely leak tight. However, even with the utmost care in the process, faulty packaged products cannot be avoided 100 per cent of the time. Defects in the sealing process or in the material can easily lead to leaks, and another they might be microscopically small, they can still be incredibly dangerous. Luckily, the food processing industry has, over many years, developed package leak detection and seal integrity testing of packaging has established itself as an integral part of quality assurance.
2. Types of leak detection equipment
Depending on the types of package that is being evaluated, different technology might work better to determine the integrity of the material. To optimize quality assurance, you have the choice between package leak detection equipment for random or in-line tests – on a CO2 detection basis or as a bubble tester using a water bath.
3. What causes a leak
Seal integrity can be compromised for a number of different reasons. For example, particles of the product being packaged may come between the tray and the seal. Another potential source of a breach in seal integrity is that the heating element that creates the thermal seal may be defective or misaligned, or there may be issues with the pressure, heat and duration of the sealing process.
It is vital for quality control and quality assurance that leak detection equipment works as quickly and as accurately as possible. If seal integrity problems go undetected, issues are likely to arise with the product resulting in unwanted returns and potential damage to the relationship with a customer.
4. Seal integrity testing in a water bath
Water bath evaluation allows the detection of even the smallest leaks without the use of trace gases. Using this method, the package is placed in a chamber filled with water, and the air space is evacuated above the water level with the aid of a pneumatically operated nozzle, compressing the package under water. Air or fill gas escapes at the leak point, and heads upwards to the surface of the water as bubbles. With this bubble test, it is also possible to determine where precisely the package is leaking. This is particularly important to identify which element of the packaging process is faulty, for example whether there is a material defect or if the seal integrity is defective.
5. Leak detection of packages with CO2 as a trace gas
Other integrity testing systems rely on CO2 to detect a leak. The use of CO2 is a particularly cost-effective method compared to helium or hydrogen. Products which are packaged under protective gas contain CO2 in most cases as a component of the protective atmosphere – other products produce CO2 themselves. An adjustable vacuum is generated in the measuring chamber. The pressure difference between the package and the chamber results in CO2 escaping through the leaks. This increases the CO2 concentration within the chamber. The sensitive CO2 sensor responds to this increase and thus detects even the smallest leaks.
6. It’s just not worth the risk
Unfortunately, preventative measures can be easy to forgo when there doesn’t appear to be a problem. When it comes to the safety and quality of food though, it is simply not worth the risk. To ensure quality control and integrity of the seals, products coming off the packaging line must regularly undergo tests by package leak detector equipment.