ISO 1988 Sampling Question

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Posted in: , on 21. Apr. 2006 - 11:40

Hi all,

I was analyzing ISO 1988-Hard Coal Sampling and I got stuck somewhere while calculating the amount of coal that would be taken by a single operation of an automatic sampler.

According to the tables I need to take 32 increments for ash and 16 increments for moisture. Thus the calculated figure (from 3.3.2) for the minimum mass of increment is 3 kg for my case (for 40 mm pieces)

Since my consignment is 14400 t/day I multiply the number of increments with the factor sqrt(14400/1000), thus I find that I need to get 5 ash and 3 moisture increments per hour. Totally I need 8 increments.

I calculated before that the minimum amount of increments should be 3 kg, thus I multiply 3 by 8 and get 24 which is the amount of coal that my sampler need to take in a single operation.

However, at page 60 of the standard, there's an example and it goes like this:

800 t/hr stream wet coal so needs 32 increments for moisture and 16 for general analysis. It multiplies 16 by 6 and says it needs totally 96 increments for general analysis. I can get how it gets 6 ({(800 t/hr*24hr)/1000}*32=6) but I want to know why it did not multiply 32 by 6 as well. Or is it wrong why I think 16 is multiplied by 6.

It is totally a specific subject but I wish there's someone that could make me understand the case better which is used to calculate the amount of coal that an automatic sampler will take.

Thanks in advance

Engin

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