Chronic seal failure need advice!!

[Robio361]

Hello all,
I am new to the forum, so thanks in advance for any help. I am having issues with seal failures and have gotten no help from my vendors or seal manufacturers.
Pumping system:
Pump - Flow serve Durco Mark 3
seal - flow serve/AES single cartridge seals with Kemraz/Kalrez O-rings
Fluid - Marcamine 539....50% Methanol...1,2,3, propanetroil...Diethonalamine
Temp - ambient
Head - 75ft
flow - 150gpm
pump speed - 1750rpm
specific gravity - 0.820

Problem: After replacing seal, the seal starts to leek at about 1 to 2 months of use, which is around 12 hours of operation. The leak is not large, about a half dime size. The fluid only leaks when the pump stops running. It adds a dime size drop of fluid every time the pump stops. The fluid leak seems to be coming from the shaft O-ring. I have tried using Flowserves seal failure analysis app with no luck. My seal looks to be in predestine condition when replaced. Neither myself or my maintenance person can see any obvious signs of wear. I have tried adjusting the reverse impeller but no luck. These pumps rum about 260 -300 hours a year. Any info or advice as to what to try next would be greatly appreciated.



Thanks,

 

[rotw]

did you check with seal manufacturer (Flowserve) if the selected seal qualifies for the application, for instance is it adequate for the fluid composition? if Flowserve is not responding, did you check with another vendor (Burgmann??) what seal selection they would propose and see if they mention any concern?