Combining a nitrogen source and oxygen scavengers is an economical and efficient way to exploit the advantages of both principles. The first step is to flush the tent with humidified nitrogen down to a level of around 1.0% residual oxygen. Usually this level is achieved after flushing five times (you can be even more efficient using a vacuum cleaner, see below).
To go down from 1% to <0,2% oxygen you would have to flush several times more, with relatively pure nitrogen. At this stage, oxygen absorbers become a much more cost-effective solution.
Some essential advantages of using oxygen scavengers for going down from 1% to <0,2% oxygen:
Escal clips or our 100 cm long clips can be used to separate scavengers from the rest of the bubble. Thin films like ErgoFlex (80µ) might be damaged by using Escal clips. In this case we recommend using our clips 100 cm because these won't harm the film.
|
Some of the couplings and fittings are relatively heavy. Therefore it makes sense to install them at the bottom so they can lie on the floor without putting any stress on the barrier film. Hoses and cables should be fixed on the floor to avoid people stumbling over them and damaging the barrier film. The coupling for the nitrogen supply and the exit air should certainly be at opposite ends of the bubble or separated by a good distance.
A vacuum cleaner will save you time and nitrogen: the volume of tents without inner frames can be reduced significantly before starting the flushing procedure. As long as neither the objects nor the barrier films are endangered by this treatment it is even possible to create a slight under-pressure atmosphere in the tent. During flushing, the volume can be reduced several times by connecting a vacuum cleaner to the exit air hose.
The standard oxygen meters work with electrolytic cells which all drift noticeably within several weeks or months. You should therefore calibrate them regularly. This can be done in a very simple and cost-effective way with ou calibration bag. Or you can make your own.
Bag dimensions are 43 x 29 cm, consisting of transparent
Escal and
aluminum barrier foil.
Every bag contains 1-2 l air, 5 Ageless Eye oxygen absorbers and 5 bags of ATCO FTM 2000S. After 24h the residual oxygen level in the bags will be < 0,1% and the oxygen indicators tablets turn to pink.
After 24h the residual oxygen level in the bags will be < 0.1% and the oxygen indicator tablets turn pink. After a few days the oxygen concentration should be very close to 0%. Now oxygen meters like the GMH 3691 can be tested in a very simple way. Procedure
The calibration bag can also be used to remove single Ageless Eye indicators. Move an Ageless Eye to a corner of the bag. Separate this corner from the rest of the bag by sealing. Cut the edge off the bag and take out the Ageless Eye. The others indicators will not come into contact with oxygen. |