Components of water shipping packages for electronics?
Abord a ship electronics are typically packaged with small pouches labeled "Not-Salt – Do not eat." What is the name of this bags/pouches used and what are the chemical components?
they are there to absorb moisture and keep the components dry.
wikipedia:
A desiccant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container.
Commonly encountered pre-packaged desiccants are solids, and work through absorption or adsorption of water, or a combination of the two. Desiccants for specialised purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules.
Pre-packaged desiccant is most commonly used to remove excessive humidity that would normally degrade or even destroy products sensitive to moisture. Silica gel, calcium sulfate, calcium chloride, montmorillonite clay, and molecular sieves are commonly used as desiccants.
Rice is a common "low-tech" alternative frequently used, for example, in salt-shakers to maintain granularity of table-salt for effective pouring or shaking. Rice, however, is not a good general purpose desiccant since, unless immersed in an organism-hostile environment like pure salt, over time may be eaten by creatures that might in turn pollute the product that is being preserved. Salt itself is another effective desiccant, used for millennia in preparation of dried foodstuffs. A specific usage of dessicant would be in double glazing where it is placed inside the spacer between the air space and window edge. This stops heat loss via the actual spacer.
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May 25th, 2010 at 9:54 pm
they are there to absorb moisture and keep the components dry.
wikipedia:
A desiccant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container.
Commonly encountered pre-packaged desiccants are solids, and work through absorption or adsorption of water, or a combination of the two. Desiccants for specialised purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules.
Pre-packaged desiccant is most commonly used to remove excessive humidity that would normally degrade or even destroy products sensitive to moisture. Silica gel, calcium sulfate, calcium chloride, montmorillonite clay, and molecular sieves are commonly used as desiccants.
Rice is a common "low-tech" alternative frequently used, for example, in salt-shakers to maintain granularity of table-salt for effective pouring or shaking. Rice, however, is not a good general purpose desiccant since, unless immersed in an organism-hostile environment like pure salt, over time may be eaten by creatures that might in turn pollute the product that is being preserved. Salt itself is another effective desiccant, used for millennia in preparation of dried foodstuffs. A specific usage of dessicant would be in double glazing where it is placed inside the spacer between the air space and window edge. This stops heat loss via the actual spacer.
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References :
May 25th, 2010 at 10:33 pm
Silica Gel. It is known as a dessicant. Actually, they put it in the box for pretty much all electronics, on ship or on land.
It is sodium silicate. Other chemicals are mixed with it to make it turn color when it has absorbed enough moisture to make it not work as well, those chemicals are typically toxic or carcinogenic. You can also get non-adulterated silica gel, but it stays clear.
It has a very porous structure, which is why it absorbs water so well.
References :
http://www.silicagelpackets.com/
http://en.wikipedia.org/wiki/Silica_gel