xPost from Pharma: Sanitary Clamp Replacement

[HotPotato]

This is an xPost from the Pharma thread since the forum looks pretty dead. I appreciate your help!

Hi All,

I have been tasked to head a project to reduce the risk of contamination in our bio-pharma production facility. The main goal is to roll out the use of torque wrenches to use on sanitary wing-nut triclamps. I have been asked to replace the sanitary clamps on all of our bioreactors (nearly all clamps from 2003). This would be the replacement of >2500 low pressure wing-nut tri-clamps. I have already replaced the clamps on 2 bioreactors and I'm starting to wonder if this activity is really worth it?

Is it best practice to replace the clamps after some time? Granted, some clamps are so old they have residue on the inside of them, but do the clamps, wingnuts, or threads loose their integrity after a time?

Thanks!

 

[IRstuff]

That depends their usage; certainly, there will be wear and tear on the threads through constant usage. But that's pretty much it, unless you're managing to overstress the clamp itself.

From a cleanliness perspective, they probably should be replaced; there have been incidences of contamination within sterilization chambers in hospitals.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[EdStainless]

Are all of your flanges and clamps of the same brand? If not then that is the first issue.
It would be straightforward to build a gauge to check the clamps.
I have seen wear on the clamp surface and I have seen hinge pin wear that both impact clamping.
You also have to have very tight control on the seals. If they are too hard or too soft they will not fill the gap properly.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[HotPotato]

It would be near impossible to determine where the clamp ferrules were sourced from as we have many different skid providers. The clamps are from a few different vendors, but mostly Alfa Laval. Torque wrenches have not been used on these clamps to date so I couldn't imagine they have been overstressed.

They are probably 15 years old. Would that wear and tear on the threads cause inaccurate torqueing of the clamp (excluding galled threads)?

How would you describe the impact to clamping effectiveness of an old clamp? Is it that the distributed forces become uneven?

 

[IRstuff]

Perhaps we should back up a bit. Please explain what the clamps are supposed to be doing and what the torque wrenches are supposed to do.

How old are the seals?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[jari001]

When I worked at a vaccine filling site clamps were replaced for aesthetic reasons (why give something to an auditor to nitpick). It could be the result of the clamp looking beat up (from being dropped, rubbed against other metal pieces), tarnished from the cleaning and sterilization cycles, etc. I was not aware of a program to track clamp life because of lifetime concerns.

The contamination risk really depends on how careful the operators are when assembling and disassembling and if their training on the matter was sufficient. I'm sure you know that you can't just wave sanitized components around higgly-piggly and expect things to stay clean. It will be imperative that the torque wrench be kept clean and possibly sterilized regularly if it's going to be used on sterile status items.

 

[Compositepro]

What does the manufacturer say? I do not have a lot of experience with these fittings but they appear to be very reliable and robust, and I have never heard of any issue with them. I do not see that torque wrenches would improve things.

 

[EdStainless]

Not all of the makers use the same dimensions, and some bias tolerances to one side or the other.
I have seen some combination that simply are not reliable together.
If the clamps and flanges are not a good match then torque will not be a reliable indicator of suitable clamping. You really should test some and measure the actual gap between the flanges, that is the critical dimension. If you have consistent components then torques is a good measure.
If you haven't been using torque wrenches I would assume that they are being seriously over-tightened.
I have seen plants where all clamps and flanges have mfg marks on them, and the clamps have mo-yr stamped into them. As the become older (if they are used a lot) the inside surfaces can become worn changing the way that they mate to the flanges. I have seen them worn to the point of bottoming out and not applying enough clamp force, or clamping unevenly.

With seals some will become hard with age, and some soft. Depends on the specific compound and the service conditions.
Either way and you get a seal that traps materials and is hard to clean.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[bimr]

Have you contacted the manufacturer of the clamps and asked for their recommendations?

 

[quark]

If you see residues (of the product, I suppose) in the clamp groove, there is misalignment of TC ferrules. This is a bigger problem than clamps losing their integrity. The major failure factor for clamps is damage of threads. Replacing all clamps at once doesn't add any value unless all are rusting.