What sealant should be used for double-end face mechanical seals in concentrated sulfuric acid media?
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Concentrated sulfuric acid seems to react with all organic and inorganic substances. For the seal fluid used in double mechanical seals for corresponding pumps, what medium would be most suitable? The manufacturer recommends using 15# industrial white oil; however, it’s unclear whether it will react if it leaks into the process medium Have any friends who have used it given feedback?
Fluoroplastic magnetic pumps rotate the rotor through magnetic drive; they do not require mechanical seals and are completely sealed pumps, which eliminates the risk of fluid leakage. Fluoroplastic magnetic pumps are safer and more reliable for transporting concentrated sulfuric acid. If the medium contains fine particles, magnetic pumps cannot be used; instead, a fluoroplastic centrifugal pump should be selected. For the mechanical seal, a wear-resistant type such as a cemented carbide mechanical seal should be chosen
From 2011 to 2013, I was in charge of systems that used many magnetic pump units. Under similar operating conditions with the same medium, the failure rate of magnetic pumps was generally higher than that of double-end face seals (both were domestic brands), and the cost of replacement parts was very high when they failed. Magnetic pump systems are said to be leak-proof, but many failures occur due to wear of the shielding sleeve; once it wears out, leakage still happens.
From 2011 to 2013, I was in charge of systems that used many magnetic pump units. Under similar operating conditions with the same medium, the failure rate of magnetic pumps was generally higher than that of double-end face seals (both were domestic brands), and the cost of replacement parts was very high when they failed. Magnetic pump systems are said to be leak-proof, but many failures occur due to wear of the shielding sleeve; once it wears out, leakage still happens.
For base flow rates and process requirements, metering pumps can be considered; the flow-through components are made of PVDF, so they can handle concentrated sulfuric acid without issue. Fluorinated linings on centrifugal pumps are also an option, though leaks with such pumps can be quite problematic