A. Technical arguments

1 - Patent
An international patent number protects DES-CASE breathers, manufactured since nearly 20 years (Disposal breathers U.S. Patents 4,548,624 & 4,504,289)
2 - Physical & Mechanical principles
A reservoir breathes. After each inhalation, there is an exhaust. Silicagel stops water vapor by adsorption principle (Silicagel is able to retain 40% of its dry weigh in water), this chemical principle is reversible. It means that exhausted dry air is able to regenerate Silicagel.
If you shake a surface media filter, it cleans itself.
From those principles, DUPONT de NEMOURS media filter, used by DES-CASE breathers, cleans itself (at around 95%) when the reservoir exhausts and the dry air exhausted by the reservoir through the breathers regenerates the Silicagel at around 80%.
3 - Filtration
To indicate a filtration level for oil is one thing, to be able to certify filtration efficiency at atmospheric pressure for air breath is an other problem.
DES-CASE breathers use DUPONT de NEMOURS filter elements. These ones stop particules and dust from an half micron (0.5) with an efficiency of 73.5% and particules equal or over three (3) microns with an efficiency of 100%.
4 - Water retention
Silicagel offers the best technical and cheaper solution to stop water vapor contained by ambient air. Electrical engineers use it since 50 years to protect oil reservoir on electrical transformer. But it is necessary to know the chemistry of Silicagel and air.
DES-CASE offers a complete line of breathers able to stop from 0.6 to 180 liters of water. In those breathers, as ambient air contains dust and humidity, air, firstly is cleaned by the DUPONT de NEMOURS filter element (0.5 micron), after the Silicagel dehydrates air. At the end, to be secure, clean and dry air is filtered again to be sure to have no Silicagel particules in air, which entrance in the reservoir.
5 - Collapse or saturation indication
It is necessary to have a good collapse indicator to answer correctly to maintenance people needs. Silicagel uses a chemical indicator, from blue the breather turns to pink color when it is saturated by water. But, to use this information as the general remove indicator, you need to be sure that your breather will be effectively saturated by water before it will be collapse by dust and particules.
If you refer to the point N°2 of those informations, you note that DES-CASE breather cleans itself four times better than it dries itself. 20 years of feedback show ,taht the DES-CASE breathers are always saturated by water before being collapsed by dust.
6 - Time life of the breather
As you know, the DES-CASE breathers exist since around 20 years. In Europe industry uses it since 10 years. Around each minute a new DES-CASE breather is installed on a reservoir. Today, in Europe, our end-users reach around 14 months of duration with our DES-CASE disposable breathers.