Selection of desiccant and dosage calculation

One. Selection of desiccant

1. choose the type of desiccant raw materials according to the storage conditions of the customer's products (permissible humidity conditions).

2. according to other characteristics of customer products, choose the right packaging materials. For example: the requirements of dustproof, the speed of moisture absorption, whether direct contact with food, whether it needs antistatic, cost requirements and so on.

3. according to the size of customer orders and the period of use of desiccant (storage time), choose the appropriate barrier bag (the shelf life of desiccant).

Two. Dosage calculation

The following three factors need to be considered in calculating desiccant dosage.

1. the water contained in the sealed container (or sealed package).

2. Moisture contained in a water bearing material inside of packing, such as wood, paper, foam materials, etc.

3. during the entire storage and transportation period, water vapor from the package is penetrated into the package.

We use the following formula to calculate the amount of dosage

In the following form:

m：The amount of desiccant，unit；

V：The internal volume of a container (or packing bag)，m³；

b：Water content in the environment when the product is packed,g/m³；

c：How much moisture in the water containing material will evaporate into the package，%；

A：The surface area of the packing is obstruct，m²；

WVTR:Water vapor transmissivity in barrier packing，g/m².d；

e:Correction factor for water vapor transmission under actual storage conditions (relative to test conditions)

t：Total storage and transportation time,d

a：In real storage conditions (safe storage conditions for goods),the amount of water vapour adsorbed by each unit of desiccant，g/unit