DESICCANT CLAY SACHETS
Desiccant activated clay sachets are still used in many industries
and regions, in preference to silica gel sachets.
The adsorption capacity of desiccant clay is lower than silica gel,
so more is needed to do the same job
e.g. the equivalent of a 25 gram silica gel sachet would be
a desiccant clay sachet containing 28 to 33 grams.
This is also known as 1 unit of basic desiccant.
This weight of a Desiccant Unit derives from American and German standards (MIL-D-3464E and DIN 55473 respectively)
which define the Desiccant Unit as:
‘the quantity of desiccant, as received, which will adsorb,
at equilibrium with air at 25 degrees Centigrade, at least:
(a) 3.00g at 20%RH
(b) 6.00g at 40%RH’
The lower cost of clay does mean that clay sachets can be cheaper
than their silica gel sachet equivalent, even though more clay
is needed to offer the same performance.
Standard size desiccant clay sachets
These are made in Tyvek and non-woven fabric outers and can variously meet
MIL-D-3464E Type I (general purpose) and Type I and II (non dusting)
and DIN 55473 Class A (dust free) and Class B (dust less) classifications. Please ask.
½ unit (105 x 50 mm)
1 unit (120 x 50 mm)
2 unit (135 x 80 mm)
4 unit (175 x 80 mm)
8 unit (185 x 125 mm)
16 unit (270 x 125 mm)
32 unit (320 x 160 mm)