Drierite® Desiccant, Indicating
DRIERITE® desiccants are made from the naturally occurring mineral, gypsum (Calcium Sulfate), and are available in several varieties designed to solve all types of drying problems. Drierite is an all-purpose drying agent for the efficient and rapid drying of air, industrial gases, refrigerants, organic liquids and mixed solvents. It is used to maintain a dry atmosphere in storage spaces, vaults, commercial packages and other enclosures; and for the protection of hygroscopic materials or materials subject to mildew, corrosion, rust or other deterioration caused by high humidity.
Efficiency
The moisture remaining in gases dried with Drierite at 25°-30°C is 0.005 mg/liter (data verified by the National Bureau of Standards). Air is dried to a dew point of –100°F. Organic liquids are dried to the low ppm range. There is little change in efficiency at temperatures up to 100°C.
Capacity
For the drying of liquids, Drierite instantly absorbs 6.6 weight percent water by chemical action, creating the hemihydrate of calcium sulfate.
For the drying of gases, Drierite has a water capacity of 10 to 14 weight percent. This increased capacity is due to combined chemical and capillary action. Drierite granules have 38 percent pore space volume, which accounts for the additional capacity. Above 6.6 percent, the capacity varies inversely with temperature and directly with pressure and the partial pressure of water vapor.
Regeneration
All forms of DRIERITE can be regenerated many times for reuse.
INDICATING DRIERITE
Indicating Drierite is impregnated with cobalt chloride. Indicating Drierite is blue when dry and changes to rose red upon absorption of moisture. The color change is pronounced and clearly visible. This makes Indicating Drierite valuable when it is necessary to know with certainty that dryness is being maintained and to signal when the drying agent should be replaced. It has the same efficiency as Non-Indicating Drierite, and somewhat greater capacity due to the desiccating effect of the cobalt chloride. Contents 97% CaSO4, 3% CoCl2. It should be noted that Indicating Drierite should not be used for the drying of ammonia, NH3, since ammonia reacts with inorganic chlorides.