API 682 (3rd edition) mechanical seal temperature limit
API 682 (3rd edition) mechanical seal temperature limit
(OP)
I have a C2A3A235261 flowserve mechanical seal: Category 2--Arrangement 3--Type A. Do someone know the temperature limit for this kind of seals? I have done some research through the internet and apparently Category 2 can work up to 400 ºC (750 ºF). However when it is type A... the temperature limit can be 250 ºC (480 ºF)





RE: API 682 (3rd edition) mechanical seal temperature limit
RE: API 682 (3rd edition) mechanical seal temperature limit
Depends of materials and design (model).
What model you have? QB, QBQ, BX, BXH, BXRH, etc?
What materilas are components made? o-rings, faces, bellow or spring..
RE: API 682 (3rd edition) mechanical seal temperature limit
RE: API 682 (3rd edition) mechanical seal temperature limit
316 SS, SIL CAR, C-276, 304 SS... most of them correct for high temp, except for the gaskets which are FFKM... am I right?
The seal is Flowserve QBQ
RE: API 682 (3rd edition) mechanical seal temperature limit
RE: API 682 (3rd edition) mechanical seal temperature limit
RE: API 682 (3rd edition) mechanical seal temperature limit
First of all I answer your questions:
1.- We do not have temp measure in Plan 52.
2.- Same as the process fluid: Dowthwrm A.
The fact is that we are observing that the seal faces are degrading themselves very quickly (at least much faster than expected). Some more comments:
1.- It is true that our barrier fluid can degrade to create coke. However, for this, it is needed O2... but our system is blanketed with N2 and inside the seal the pressure is always much higher than the atm... So no O2 inside the seal...
2.- I am trying to investigate the Carbon grade so that to know the suitability as you said in your post.
3.- Independtly of all of this, I have a huge doubt... If my seal is type A and according to API 682, type A is only recommended for temperatures up to 176 ºC... I guess this is the max allowable temperature inside the seal. am I right? I ask this because in the pump suction the nominal temperature is 300 ºC. However, inside the seal we have on average:
- Seal outlet (towards plan 23 cooler): 140. (since august we are observing: 250 ºC)
- Seal inlet 80. (since august we are observing: 150 ºC)
I do not know if the temperature increase is due to that the degraded faces allow higher flow from the pump to the seal and the cooler is not able to cool it down...
Finally, in the documentation I uploaded, the supplier stated the max allowable temp inside the fluid is 327 ºC... This contradicts API 682. Am I right?
Why Type A is not valid for temps over 176 ºC taking into account that al materials are suitable to withstand temp over 176 ºC?
RE: API 682 (3rd edition) mechanical seal temperature limit
RE: API 682 (3rd edition) mechanical seal temperature limit
Arrangement 2 (A2) is a dual unpressurised (tandem)seal. But 53B is for an arrangement 3 (A3) dual pressurised seal with a pressurised barrier fluid, pressurised via a bladder accumulator.
Perhaps I'm missing something
RE: API 682 (3rd edition) mechanical seal temperature limit
The material code 5AKX on the drawing tells you that the carbon grade is resin bound.
The title block clearly indicates that this is a non-pressurised seal - as does the terminology "buffer" as opposed to "barrier".
If the faces had degraded to allow higher flow through the inner seal, you should get a high level/high pressure alarm in your Plan 52 system. However this depends on how it is set up - do you have a system drawing?
If there is no indication of increased leakage through the inner seal, I would suspect your cooler is fouled/blocked on the CW side.