Tips and tricks from our practical experience

nach obenCombining nitrogen generators or bottle nitrogen with oxygen absorbers

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.
As soon as the oxygen concentration is down to <1%, the clip is opened and the scavengers slide into the bubble.
If the flushing time is to take several days, it might be wise to make separate compartments for the oxygen scavenger and the desiccant bags

The same principle can be used to sneak any object into the bubble without introducing much oxygen. As soon as an edge of the tent is separated with a clip, this edge can be opened and resealed after filling.

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.


nach obenWhere to put the couplings?

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.

nach obenHow to check air tightness of the bubble

An easy test for checking the tightness of the bubble is to evacuate it with a vacuum cleaner and see whether the low-pressure atmosphere can be maintained for several days. This technique only can be used if the deflating bubble doesn't endanger the art objects or if there is no risk of puncture of the film by sharp edges. Other helpful tools are air flow indicators for leakage detection.

nach obenUse a vacuum cleaner for more efficiency

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.

nach obenCalibration bag for oxygen meters

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.

Test of Oxygen meter GMH 3691
Display shows 0,1% residual oxygen.
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.
  • put rubber foam sticker close to an edge of the bag
  • push the needle of the GMH 3691 through the foam sticker without puncturing the aluminum side of the bag
  • measurement can be carried out (oxygen level in the bag = 0%) , approx. 0.2 l of air will be pumped out of the bag
  • pull the needle out of the bag
  • re-seal the edge so the puncture of the needle will be situated on the outside of the bag. New measurements can be carried out after 24h
Removal of single indicators
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.

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