Selection of pumps and pump seals under such operating conditions
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This post was last edited by mli1979 on 2018-7-4 09:17. Industrial protein is produced using animal leather and lye; the dissolved protein solution is then pumped into a filter press for filtration. The pH of the protein solution is around 13; it has a certain viscosity, the temperature is around seventy to eighty degrees, and the solution contains a small amount of sediment. Currently, centrifugal pumps are being used, but the mechanical seals wear out very easily and cause leakage (leakage occurs every three to five days). The manufacturer has now switched to external mechanical seals, but the results are still not satisfactory; moreover, the SKZ80-50-250 external mechanical seals used come at a high price. Everyone, do you have any recommendations or suggestions regarding pumps or mechanical seals for this type of environment?
For feeding the filter press, what type of seal was used before? How long is its lifespan? What kind of pump is the poster using? Why does the manufacturer want to switch to an external machine seal? The price of external machine seals isn’t very high; an internal double-face balanced seal with a PLAN54 flushing system can be used instead. Additionally, the 80-50-250 pressure can reach 8 kilograms; generally, 5-6 kilograms is sufficient for feeding a filter press
This operating condition is similar to one of our medium-related scenarios: the temperature is 70–80 degrees, the pH level is 12+, and the medium is crystalline. In our case, there is not only seal leakage but also alkali embrittlement in the stainless steel pipes.
It used to be SKZ80-50-250 as well, but it was much smaller than the one in use now. All the acid- and alkali-resistant materials that were used back then started leaking within a week. It says on the pump that it is a process flow pump, but it seems to be a centrifugal pump. . I originally wanted to upload a picture, but for some reason the webpage freezes as soon as I try to do that. External machine seals are very expensive, which is why I am seeking from all of you **solutions or ways to extend the lifespan of these external machine seals.
Mine does not crystallize, but the medium has a certain viscosity (it’s a protein solution), and it contains various sedimentary impurities. Steel pipes; no alkali embrittlement occurred. The impeller was originally made of iron, and cavitation occurred in both the impeller and the pump cover; it has now been replaced with stainless steel, but it’s not yet certain whether cavitation will occur again. Under cavitation conditions, the impeller may also suffer from alkali embrittlement, resulting in multiple fractures in the impeller cover.
Change it to the plan54 double-seal version
Leaking material in just one week is too fast; it’s better to go with the PLAN54 double-end face seal solution. Similar use cases show that the machine seal can work fine for over a year.
The smaller one is the old machine seal, while the larger one is the newer one; the models provided by the manufacturer are all SKZ80-50-250
Why is the suspension part designed this way? The external enclosure seal will also leak; is there an auxiliary 62 solution available? A PLAN32 modular mechanical seal with a large spring sand prevention mechanism should work, right?
How is a pump with such a high head used in this direct-connected format? It looks pretty similar to a magnetic pump, hehe. OP, you might consider using this type: a corrosion- and wear-resistant slurry pump with an open impeller and double-end mechanical seals.