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Anonymous Poster

Cylinders, Valves and Medical Gas

06/26/2008 5:52 PM

a medical gas is to be packaged in cylinders. the client needs to qualify various valves (SS and Aluminum) and various cylinders (SS and Aluminum) and must be included in the DOE. my question is...; how can i do a 2k factorial and Quantify Variable Relationships whilst including the cylinders and the valves from two different vendors? my understanding is that these are not variables???? How can i arrive at worst case scenarios by bracketing vendor equipment?

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Guru
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Join Date: Feb 2008
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#1

Re: Can equipment material be used in a DOE?

06/26/2008 6:28 PM

The detail is in how you plan the experiment.

Yes the valves, cylinders and such can be considered variables if there is any "suspected" way that they could influence the outcome.

If the experiment prooves no correlation between Al and SS, then the experiment worked to confirm they are not contributing variables/inputs.

For instance if one parameter your customer is interested in is failure of the threads during fitting and removing valves, then I suspect that aluminium would exhibit some problems relating to torque to strip, progressive damage to threads by repeated assembly/dissassembly, and especially Al to Al threads binding tight into each other.

There could also be problems using SS and Al in a mixed system where the SS parts damage the softer Al.

If gas volume is important, then the differential thermal expansion while filling may mean that SS and Al have different performance.

Your experiment needs to focus on the outcomes that are important to you (or the customer) and design the experiment with forced "opportunities" for those outcomes to be observed.

If you want an experiment desinged, then reply to the post with the other parameters involved and we'll see what can be done.

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Anonymous Poster
#2
In reply to #1

Re: Can equipment material be used in a DOE?

06/26/2008 6:55 PM

First I want to thank you for the input...

now for the factors we have:

P1=initial pressure of system INPUT Phase I

P2=receiving pressure main vessel1 (final) OUTPUT Phase I

P1=P2 at equalization Phase II(pressure of main vessel will fill 19 smaller vessels)

W1=weight of V1 INPUT Phase I

W2=weight of V2 OUTPUT phase II

Not sure, but i think i might have to insert anti-liquification temp and or ambient temp. Mind you this process is automated and recipe driven...

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Guru

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#3
In reply to #2

Re: Can equipment material be used in a DOE?

06/26/2008 9:35 PM

First, can you give us a better idea of describing what success or failure of the expected response variables are. (failure modes or (bad))

What are the factors that would disqualify a valve or tank?

Then we can help you create the test design that will show whether each of these is pass / fail.

Its difficult for me to understand how wieght or pressure will be the determining /differentiating factors when materials are the tested variables/factors. But i could just not be grasping what you are trying to prove.

milo

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Anonymous Poster
#4
In reply to #3

Re: Can equipment material be used in a DOE?

06/26/2008 10:11 PM

Sorry colleagues, but my associate has not revealed enough info for me either. my associate was asked to design a unified or rather combined Validation/DOE for a client from info which was derived from their FMEA/matrix. she called me and asked to help thinking that i would have a quick answer or methodology. i responded that i needed more info/input. she asked if i could ask this forum for help. apparently it seems that we could do it but we'd need more time. meanwhile our client is expecting a design by tomorrow (Friday). she (my associate) left the brunt of the work to me. i have all, or some, of the documentation but she asked me not to disclose the info in lieu of a breach in confidentiality. i'm stuck in a quagmire because i need the help but don't know how to convey the info without compromising her, our client, my contractor (company) and my word. i'd be embarrassed if someone saw this. please advise if i can contact via private email. BTW i am a member and contributor known by CR4 but prefer to remain anonymous for the reasons stated. also, my associate refuses to say we just can't do it...

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Guru

Join Date: Jul 2006
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#6
In reply to #4

Re: Can equipment material be used in a DOE?

06/27/2008 3:32 PM

I sent my reply privately via email this AM.

milo

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People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is unseeable,eternally active life, contemplated in repose. Goethe
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Anonymous Poster
#5

Re: Can equipment material be used in a DOE?

06/26/2008 10:16 PM

colleagues, i will try to encrypt or remove incriminating info from the documents...,just give me some time.

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Power-User

Join Date: Dec 2007
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#7

Re: Cylinders, Valves and Medical Gas

06/28/2008 10:41 PM

depending on where you are located there is a very definite possibility both supply of the valves and, certification of your cylinders can be arranged for through a company in caistor centre ontario canada

'da ber

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Anonymous Poster (3); barfnagler (1); Just an Engineer (1); Milo (2)

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