The useful life of a breather is dependent on three variables. They are, in order of importance,
- Frequency of Breathing
- Quantity of Silica Gel in the breather
- Ambient Humidity in the work area
Frequency of Breathing
Means how often does a new batch of wet air pass through the breather. Each time this happens water vapor is retained and the breather life is shortened. Examples of the extremes would be a storage tank that has fluid drawn out once a day; one load of water per day to be removed and retained in the breather = long life. A hydraulic cylinder strokes every 30 seconds; each time a new load of water to be removed and retained in the breather = short life.
Quantity of Silica Gel
The water holding capacity of a breather is directly proportional to the amount of silica gel in the breather. We have a chart that gives the maximum water capacity for each Watchdog part number. Our Cross Reference documents also show the comparison to various Des-Case models.
Ambient Humidity in the Work Area
Most users believe that the ambient humidity is the major factor in the life of breather; however, humidity works for us as well as against us; The amount of water a given volume of silica gel will hold is a function of the humidity; as the humidity increases the efficiency of the silica gel goes up, to approximately 40% of its own weight. Therefore as each load of wet air passes through the breather the air with higher humidity brings more water vapor to adsorb, but the silica gel can adsorb more at the higher humidity level. The end result is a small decrease in the life of the breather at higher work area humidity levels, but this is not as significant as the other two life factors. In certain environments, such as paper mills or areas with steam present, ambient has a more negative effect on the life of the breather.
After explaining these factors to a customer, they probably will still say, OK, how long will my breathers last?. Most breathers in industrial applications will last 3 to 6 months, if sized properly. The first breather put on a tank or reservoir that has been in operation for a period of time will usually last a shorter time than subsequent breathers because it is having to dry air leaving the reservoir as well as coming in.
Posted in: Watchdog Desiccant Breather