Moisture-indicating Molecular Sieves are beads that have been chemically impregnated to display a blue color when fully activated by removing the water of hydration. When a gas stream is dried using this product, the blue color will turn to pink as water is adsorbed denoting saturation of the sieve. The sieve may then be reactivated at 200°C under vacuum or nitrogen atmosphere for several hours. More conveniently, the sieve may be replaced from fresh stock.
Type 4A Moisture-Indicating Molecular Sieve is the preferred adsorbent for static dehydration in a closed gas or liquid system. It is used as a static desiccant in household refrigeration systems, packaging of drugs, electronic components, perishable chemicals and as a water scavenger in paint and plastic systems. Also used commercially in drying saturated hydrocarbon streams.
Type 4A Moisture-Indicating Molecular Sieve allows the user to determine whether a bed of desiccant is nearing water vapor saturation. Moisture-Indicating Molecular Sieve can be used either "full-strength" to maximize the effect of the color-change indicator, or may be mixed with non-indicating product for a more economical approach to the application.
Nominal Pore Diameter: 4
Molecules Excluded: > 4 effective diameter, e.g., propane
Not suitable for liquid phase applications
|Nominal Pore Size|
|Type of Crystal Structure|
|Equilibrium Water Capacity @ 25°C|
|Crush Strength (beads)|
|Heat of Adsorption (max.)|
1800 BTU/lb H2O
|Moisture Content as Shipped (measured @ 600°F)|