LIQUID CO2 SEAL LEAKAGE.

[shyamshins]

thread819-353147

JJ PEELIN SIR & FORUM MEMBERS,

With ref. to THREAD819-353147 in which seal drawing is attached this single non cartridge seal is found leaking again after

running for 8 months.

I am attaching failed seal carbon & Silicon carbide photos for your reference. Pls. suggest me how can I solve this seal problem as this seal failure is repeated.

 

[shyamshins]

Sir in this thread I am attaching SILICON CARBIDE FACE photo.

Carbon has scoring marks on face & pls. note that spot on Silicon carbide face is light relection.

 

[JJPellin]

I believe all of my recommendations from the last time are still valid. I would add one point. If the glycol you are using is actually automotive anti-freeze, then it is even more important to stop using it. At the conditions between the seal faces, the anti-corrosion additives in the anti-freeze will come out of solution and plate out on the faces. This is the most likely cause of the scoring damage you see on the faces. If you insist on using this seal design, I would recommend a different fluid. Perhaps Methanol or Glycerine would work better. But, you would have to research the properties and material compatibility.

Johnny Pellin

 

[HansBrinker]

Hi shyamshins

First: whatever JJ has already said - do that
Plus: I looked at your carbon pic and it looks to me like the beginning of blistering in a couple of spots. Have a very close look under magnification - I think you'll see this. It's a fairly common problem with ammonia compressor seals and I've seen it in CO2 pumps. Is this seal face antimony filled carbon? If not, talk to your seal vendor about switching to that material. Consider going a step further and have this face also made from silicon carbide. Running a short while leak free and then having a leak develop is also symptomatic of carbon blistering. The CO2 gets absorbed and then an upset in the system, more likely temperature than pressure related, will cause it a sudden expansion and thus the blister. Try silicon on silicon, I think you'll get your fix.