Desiccant consumption calculation
Calculation method by JIS Z 0301
The desiccating agent, please find the consumption by the following expressions depending on a use and the situation.
(1)
W: Consumption (g) of the desiccating agent
R: Of JIS Z 0208 [vapor permeance test method (cup method) of the moisture-proof wrapping]
Vapor permeance (g/m2, 24h) of the moisture-proof wrapping by condition B
A: Surface area (m2) of the moisture-proof packing
t: Packing period Sunday (= 24h) (1)
h1: Mean humidity (%) of the fresh air during a packing period
h2: Mean humidity (%) (2) in the packing during a packing period
K1: Moisture-proof wrapping coefficient (3) to be decided by kind and average temperature θ ℃ during a packing period
C1: Moisture absorption rate (%) of the desiccating agent at the time of the beginning to use
C2: Equilibrium moisture absorption rate (%) of the desiccating agent in the relative humidity of the maximum permitted by the packing inside
K2: Wrapping coefficient (4) to be decided by a moisture absorption rate with the absorbency in the packing
D: Mass (g) of the wrapping with the absorbency in the packing
R: Of JIS Z 0208 [vapor permeance test method (cup method) of the moisture-proof wrapping]
Vapor permeance (g/m2, 24h) of the moisture-proof wrapping by condition B
A: Surface area (m2) of the moisture-proof packing
t: Packing period Sunday (= 24h) (1)
h1: Mean humidity (%) of the fresh air during a packing period
h2: Mean humidity (%) (2) in the packing during a packing period
K1: Moisture-proof wrapping coefficient (3) to be decided by kind and average temperature θ ℃ during a packing period
C1: Moisture absorption rate (%) of the desiccating agent at the time of the beginning to use
C2: Equilibrium moisture absorption rate (%) of the desiccating agent in the relative humidity of the maximum permitted by the packing inside
K2: Wrapping coefficient (4) to be decided by a moisture absorption rate with the absorbency in the packing
D: Mass (g) of the wrapping with the absorbency in the packing
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Note (1)
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When a change of temperature, the humidity during a packing period is big, you divide a packing period properly and calculate the desiccating agent consumption during each period and may add this. |
| (2) | For kisanchi, I take the middle value with the humidity of the maximum permitted within humidity and packing in the early packing. |
| (3) | I calculate the value of K1 by the next expression. |
 Pθ: I can put it in mean temperature θ ℃ during a packing period
Moisture-permeable rate (g, cm/cm2, s, kPa) of the moisture-proof wrapping P40: Moisture-permeable rate (g, cm/cm2, s, kPa) of the moisture-proof wrapping in 40 degrees Celsius pθ: I divide saturated steam in θ ℃ (kPa) p40: I divide saturated steam in 40 degrees Celsius (kPa) |
■I show a value of K1 in various temperature of the film for the reference ... a lot of packing to the reference list.
Film
| 40 degrees Celsius
| 35 degrees Celsius
| 30 degrees Celsius
| 25 degrees Celsius
| 20 degrees Celsius
| 15 degrees Celsius
| 10 degrees Celsius
| 5 degrees Celsius
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Polyester
| 11.1 x
10-3 | 7.3 x
10-3 | 4.9 x
10-3 | 3.1 x
10-3 | 2.0 x
10-3 | 1.27 x
10-3 | 0.81 x
10-3 | 0.48 x
10-3 |
Low density
Polyethylene | 11.1 x
10-3 | 7.0 x
10-3 | 4.5 x
10-3 | 2.8 x
10-3 | 1.8 x
10-3 | 1.05 x
10-3 | 0.63 x
10-3 | 0.36 x
10-3 |
High density
Polyethylene | 11.1 x
10-3 | 6.9 x
10-3 | 4.4 x
10-3 | 2.7 x
10-3 | 1.7 x
10-3 | 1.0 x
10-3 | 0.59 x
10-3 | 0.33 x
10-3 |
Polypropylene
| 11.1 x
10-3 | 6.9 x
10-3 | 4.3 x
10-3 | 2.5 x
10-3 | 1.6 x
10-3 | 0.92 x
10-3 | 0.53 x
10-3 | 0.29 x
10-3 |
Polychlorination
Vinylidene | 11.1 x
10-3 | 6.5 x
10-3 | 3.9 x
10-3 | 2.2 x
10-3 | 1.3 x
10-3 | 0.74 x
10-3 | 0.40 x
10-3 | 0.21 x
10-3 |
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Note (4)
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I calculate K2 by the next expression.
 C1: Moisture absorption rate (%) of the desiccating agent at the time of the packing start
C2: Equilibrium moisture absorption rate (%) of the desiccating agent in the humidity of the maximum permitted within packing C3: Equilibrium moisture absorption rate (%) of the wrapping with the absorbency in the humidity of the maximum permitted within packing C4: Moisture absorption rate (%) of the wrapping with the absorbency when I put it in the packing |
(2)
I calculate R = 0, the consumption of the desiccating agent at the age of D = 0 by the next expression.
I calculate R = 0, the consumption of the desiccating agent at the age of D = 0 by the next expression.
V: The space capacity (m3) in the packing container except the capacity of the packing contents
H: Absolute humidity (g/m3) in the temperature-humidity at the time of the packing
C1: Moisture absorption rate (%) of the desiccating agent at the time of the packing start
C2: Equilibrium moisture absorption rate (%) of the desiccating agent in the humidity of the maximum permitted within packing
H: Absolute humidity (g/m3) in the temperature-humidity at the time of the packing
C1: Moisture absorption rate (%) of the desiccating agent at the time of the packing start
C2: Equilibrium moisture absorption rate (%) of the desiccating agent in the humidity of the maximum permitted within packing