ALLIED DESICCANT PRODUCTS
Along side silica gels,
we offer a number of related products. Namely :
molecular sieves , capsilgels (silica gel in capsules), humidity indicator cards and papers and desiccant and fluograde activated aluminas.
DESICCANT MOLECULAR SIEVES.
Molecular sieves are desiccants with differing properties to those of silica gel. With the appearance of small opaque pinkish beads, molecular sieves are synthetically produced, highly porous crystalline metal-alumino silicates. They have many internal cavities that are linked by window openings of precise diameters. adsorption of water from air and liquids, as water molecules are both polar and very small.
Molecular sieves properties as desiccants differ from silica gel in a number of ways :
(1) They adsorb water vapour more rapidly than silica gel.
(2) They will reduce water vapour to much lower levels than silica gel, making their use essential when a very dry product or atmosphere is required.
(3) They perform more effectively as moisture adsorbers at higher temperatures (greater than 25°C) than silica gel does.
CAPSILGELS - SILICA GEL IN CAPSULES.
Capsilgels are transparent hard capsules containing silica gel. The capsule is made from hard gelatine. It consists of two cylindrical parts, a body with a hemispherical base and a corresponding cap of the same shape, but shorter. The internal diameter of the cap and the external diameter of the body are virtually equal. They are held together by a pair of circumferential grooves, that interlock when the filled body and cap are pressed together. Both non and self-indicating silica gels can be used to fill the capsule. Three standard sizes are available. These are size 1, size 00 and size 000.
| |
FILLED WEIGHT
OF SILICA GEL |
LENGTH |
DIAMETER |
VOLUME |
CAPSILGEL
1 |
0.3 grams |
19.0 mm |
6.9 mm |
0.5 ml |
CAPSILGEL
00 |
0.6 grams |
23.5 mm |
8.5 mm |
0.95 ml |
| CAPSILGEL 000 |
1.0 grams |
25.8 mm |
9.9 mm |
1.37 ml |
All
figures are approximate.
Capsilgels breathe and adsorb moisture in the same way
as silica gel sachets do. They are ideal for use in situations
where the physical space available to site a desiccant
is restricted, such as in small spaces inside moisture
sensitive scientific instruments or other electronic assemblies.
HUMIDITY INDICATOR CARDS
AND PAPER.
The actual moisture content of air within a package expressed
as a percentage of its saturation moisture content, is
termed the Relative Humidity (RH). The crucial factor
in preventing corrosion and mould growth to stored or
in transit items, is to keep the RH below 50%. Carefully
calculated, the use of silica gel sachets will keep the
RH below
this level. This can be confirmed by the use of humidity
indicator cards or papers
which give a guide to the RH level.
We currently offer the following humidity indicators :
(1) Safe/Unsafe cards or paper. The paper will change colour dependent on the RH level. A pink paper indicates that the silica gel sachets need changing to prevent moisture damage occurring. A blue paper indicates that the RH is at safe levels. Similarly, the indicator card has a spot that changes colour in the same fashion. This
can be compared to a blue fixed colour on the card - if the spot shows the same
colour or a darker blue than the fixed panel, then the RH is at safe levels. A pinker
colour and the RH is considered unsafe.
(2) Six spot indicator cards. Each spot represents a RH level from 10 - 60%. The higher
up the card the spots change from blue to pink, the higher the RH. This allows
an accurate reading of the humidity level and again, aids in indicating when
silica gel sachets require replacing.
(2) Three spot indicator cards. Similar to six spot cards, but with each spot
representing a RH level from 10 - 30%.
All of the humidity indicator cards and papers are sold in small or large quantities.
ACTIVATED ALUMINA.
Desiccant grade activated alumina is a highly porous form of aluminium oxide. It has the appearance of white chalky beads. Standard stock sizes have 1 - 2 mm, 2 - 5 mm or
5 - 8 mm beads. An adsorbent from liquids and gases, it is supplied to customers requirements, usually in bulk packs.
