FFKM o-ring selection for -25 deg C / -15 deg F continuous service

[bssem]

For my process condition (various aggressive chemicals @ -25 deg C / -15 deg F) I have been advised by our marketing dept. to select Perfluoro-elastomer (FFKM) - Kalrez / Equiv. grade suited for the low temperature service (-25 deg C / -15 deg F).

1) Can anyone suggest me a FFKM compound that is suited for such applications?

I have recently read about Parker Hifluor grade (compound V3819-75) that makes such claims.

2) Pl. let me know if you have some experience with this grade. Is Hifluor comparable to Perfluoro-elastomer (FFKM) Kalrez?

Thank-you for your advise / suggestions.
Regards,
bssem

 

[engineeringplastics]

suggest you try the kalrez website...

http://www.dupont-dow.com/kalrez

 

[unclesyd]

Fluorocarbon O-rings, in fact all O-rings, are each compounds that have very specific chemical resistance and it is very hard to predict the performance of a specific compound with different fluids based on published data and general comparisons except for some pure chemicals and petroleum products. You can use the data to narrow your selection but you need to test each manufacturers specific compound with a specific fluid in as close as possible to the actual operating conditions.

A case in point when Kalrez was introduced I looked on it as panacea for all our sealing problems where we were existing with Teflon. Our worst sealing problem was a high molecular weight Amine at high temperature. I immediately had a Kalrez O-ring installed as a static seal in a pump seal, it immediately failed. I started laboratory tests which confirmed a serious problem with Kalrez in this application.
Several years later another Fluorocarbon Elastomeric compound, Chemraz, was introduced to compete with Kalrez. Laboratory tests revealed that Chemraz was compatible with the Amine at any temperature. A Chemraz compound is the site standard today for this service.

If these are agressive chemicals I would defiantly check each O-ring compound for compatibility.

Chemraz

http://www.gtweed.com/85256D3C0038D8DA/vwContentByKey/N25QLJSV273ELETEN

I must add that Dupont immediately responded to our problem with Kalrez. They requested and I sent my failed test samples for analysis by the Kalrez team. They resolved the failure mode in a very short time and the leader of the group, the inventor, called me several times and sent me a full report on the failure mode of the Kalrez in this particular enviroment. They also produced the same chemical.
We didn't give up on Kalrez as we still use a Kalrez O-ring that cost $9,000.

 

[berti]

Hi bssem and all,

if you are searching for the combination of good (including amines and other bases) chemical resistance and excellent cold resistance (like FVMQ) have a look at SIFEL (R) of Shin-Etsu (or their daughter SHINCOR in US).

This is a quite new polymer concept with slightly different main chain than FFKM or PTFE,it is a Perfluoropolyether, and it is available in different forms as e.g. millable compound, One- and two-component-LIM etc. Price level is generally spoken between good FKM and usual FFKM.

We are supplying the material (not the parts) in some European countries and our customers are mainly smaller spezialized moulders. Let me know if you need a contact or more technical information.

Regards

Berti

 

[mjh368]

These orings cost a million dollars.
I am sure you have seend it but this is a great oring guide from parker.

http://www.parker.com/o-ring/products/allcomps3.htm#FKM