Ever since vacuum packaging was introduced, the coffee sector has struggled with one problem: micro leaks can only be detected after 16-24 hours. Sometimes machines can produce leaking packaging for hours without anyone noticing.
For a long time the only way of knowing whether there was a leak in vacuum packed coffee was to squeeze the bags. Quality checkers would squeeze each pack to see if it was soft. This checking process has now been partially mechanised. Within a second or two of being sealed the seal is tested and ten minutes after production a mechanical system extracts the leaking packs. But this only detects the bags with really big leaks.
Current leak detection method
Small leaks can be detected by allowing the coffee by waiting 24 hours. The process works as follows:.
- The packs of vacuum packed coffee are packed on trays and stored on a pallet in a warehouse.
- After four hours the pallet is pulled out from the stack and a quality control person pushes the outer bags on the pallet.
- If the quality control person finds more than two soft bags then the whole pallet has to be unpacked and all the separate trays checked manually.
- Pallets that pass the test are then put back in the warehouse.
- The same process is repeated 12 hours later.
- Eight hours later the last check is carried out although this is sometimes not done.
- Only after 24 hours of waiting in total, the coffee can be sent to the retailers.
This system of testing is labor intense and time consuming. Moreover it is not effective. Despite all the testing and checks leaks still occur in the packaging.
That is when panic sets in
Finding out exactly how many packs of coffee have leaked is difficult to determine. And as long as the percentage of leaking bags does not badly affect production statistics, not a lot will change. The vacuum packed coffee sector has learned to live with the weaknesses of checking for leaks after production. There is no budget to thoroughly tackle leak detection. That is until leaking packages roll off the production line for 24 hours non-stop. When this is discovered all the production run has to be cut open and repackaged. It is only then that management gets a real idea of the actual cost of this failure. It is at this point that the problem is so big that a need arises for better leak detection, to ensure it will not happen again in the future.
Even micro leaks can be detected within ten minutes
Oxipack has developed an in-line leak detection method that can measure the very smallest of leaks within ten minutes after vacuuming and sealing. This is done by measuring the pressure in each pack for a few seconds and then comparing this reading with the pressure in other packs. Deviations indicate a leak. The pressure in the bag can vary if the speed of the production line changes because the aroma is released during the production and packaging process. To deal with this, the in-line tester is made to exact specifications and is self regulating and actually learns.
Detecting micro leaks took 48 hours using the old fashioned squeezing method, now the Oxipack method detects leaks immediately after packaging.
The equipment pays for itself
This accurate in-line leak detection based on pressure measurement results in the percentage of leaks being markedly reduced. Moreover, the pallets no longer have to be stored for 16-24 hours. This reduces stock held and benefits working capital. Also less storage space is needed. In addition the packs do not need to be checked for leaks manually two or three times. This saves considerable in handling costs. In short Oxipack’s in-line leak detection makes the production process much more efficient.
