Inline contaminant analysis on bulky product stream

[01Mercy]

Hi all,

I have a kinda headache exercize at hand here. I hope someone can look into it with me to find a posibble solution.

Case is: I want to analyze contaminant ppmage mass based inline.

We have a bulky product stream that goes over a weighing belt with a know speed and the weight that passes is also known.
I am scanning for contaminant on a 25mm spot that is measureing with 15ms for contaminants and it's scanning the surface.

What I wanted to do is counting the hits for a contaminant in the total run and than since I have the total number of scans on the run, make the total amount of scans in the run represent the total product weight in this run.

I'm struggling to go from the counts of contaminant to the weight of contaminant on the total run. I have the mass distribution of the contaminant which I could use on the found counts but than how must I calculate to the mass of the contaminant on total amount of product.
I think this should be possible even if I scan a surface and can not relate to a certain wieght of product per scan since there is more contaminant in that weight than only the surface.

Please help if it is clear to you.
Thanks!

 

[01Mercy]

Maybe more easily said:

I have the total product mass of the run.
I have the ppm based on surface contamination count.
I have the particle mass distribution of the contaminant.

From these known facts I want to calculate the ppm of the contaminant based on mass for the total product run.

 

[MintJulep]

Your question isn't very clear, as you appear to state that you already know what you are asking for.

If you process a million pounds with 1 ppm of contaminate then you have processed 999,999 pounds of product and 1 pound of contaminate.

This is of course subject to many assumptions, that I won't state here.

 

[01Mercy]

The problem is that ppm based on counts does not equal the ppm based on mass because than the assumption is made that the contaminant has the same mass as the main product, which is not the case.

 

[MintJulep]

Then you need to know the densities.

Or develop your own empirical relationship.

 

[01Mercy]

Thanks

 

[cloa]

Even volumetric analysis would be difficult- is this product granular or big blocks? You doing some sort of mixing directly and perhaps indirectly by the conveying? and the contamination is by some sort of random process being able to seen on the surface then you need to statistically simulate how to the mixing and conveying orientates the product.

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[BillPSU]

All of these calculation assumes the sampling is random and the contamination is random and has a normal distribution. First you will have to do some empirical evaluation of your assumptions. Is the contamination random/normal? Is your visual surface contamination representative of the cross sectional contamination? If you can answer yes to these questions then you can utilize staticical methods on your findings. You will also have to decide what do you want to study either contamination by mass or volume or some other method.

Bill