§ 17
How much of the plastic has been through more than three times when we run with 25% recycled material?
Answer: When inlet and scrap are painted and mixed back into new granulate, some of the plastic goes through the machine again and again. Each time it breaks down a bit: chains get shorter, melt flow index rises and colour can change. With a fixed fraction of regrind r, the fraction of material that has been processed at least n times is rⁿ. The calculator shows how much is old and how many times the plastic on average has been through so you can stay within the customer's or material supplier's limit.
In equilibrium, the proportion processed exactly k times is: (1 − r) × r^(k−1)
The share processed at least n times: rⁿ (the sum of the rest of the series)
Average number of passes: 1 / (1 − r)
Assumes that the regenerate is evenly mixed and that the share is the same every day
| Symbol | Meaning | Unit |
|---|---|---|
| r | Share of recycled material in the mix | % |
| n | Number of runs you want to check (at least n times) | gange |
| = | Share processed at least n times | % |
| = | Average number of passes | gange |
| = | Share that is completely new (first time) | % |
| = | Share processed exactly n times | % |
Does not apply when
The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.
Substituted
Giver
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Når indløb og kassationer males og blandes tilbage i granulatet, kommer noget af plasten igennem maskinen mange gange og nedbrydes lidt for hver gang. Du regner, hvor meget der er gammelt, når I vil hæve andelen af regenerat for at spare materiale og CO₂, eller når en kunde spørger, hvor meget regenerat der er i deres emner.
I kører PP-låg med 25 % malet indløb blandet i ny granulat og vil vide, hvor meget der er kørt mere end to gange.
It means: Kun 1.56 % af plasten har været igennem mindst tre gange. I gennemsnit har plasten været igennem 1.33 times, og 75 % er helt ny.
For at spare materiale foreslås 50 % regenerat. Leverandøren anbefaler højst 5 gennemløb.
It means: 3.13 % af materialet har været igennem fem gange eller mere. Det gennemsnitlige antal gennemløb er 2 times. Tjek smelteindeks og farve på emnerne, før I går over.
Med 25 % regenerat har under 2 % af plasten været igennem tre gange eller mere.
Andelen helt nyt + andelen forarbejdet mindst 2 gange skal give 100 %.