Why some filter bags need water & oil repellent treatment?

We usually receive the questions from end users that why the filter bags need to make the finish treatment of water oil repellent? The answer is for some special circumstance, this treatment will improve the performance and prolong the using life of filter bags.
Generally speaking, following situation we consider it easy to dewing:

  1. temperature lower than 80 degree centigrade and
  2. moisture content more than 8% and
  3. the bag filter house not work continuously

When the filter bags meet the dew, while unfortunately the filter bags is without water &oil repellent, the dust will mixed with the dew and glued on the wall of the filter bags, so that will make the filter bags blocked and increase the pressure in the bag filter house, so the filter efficiency will lower and energy consumption will increase sharply, that will shorter the using life of the filter bags obviously.
Further more, once there are some acid or alkali material in bag filter house, when they meet the dew which will cause some chemical reaction so that will engender some corrosive liquid which mixed with dust and glue on the wall of the filter bags that will decay the filter bags soon and also will increase the frequency to change the filter bags.