Recently, the seal of the alkali pump in the unit has been leaking frequently; new seals start to leak just a few days after being installed. I was wondering if anyone has any good solutions
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We are using a Coollong single-stage mechanical seal with water flushing, model DBM65. The new seal starts leaking within 1-7 days of being installed, either in drops or as a continuous stream. Is there any good solution for this?
The poster could provide more details about the pump – is it single-stage or multi-stage?
The material is incorrect; please use acid- and alkali-resistant material
What are the concentration and temperature of the alkaline solution? The material of the machine seal body is generally stainless steel (except for the sealing surface), so corrosion is unlikely. The excessively low temperature controlled for flushing and cooling leads to alkali crystallization, which damages the sealing surface of the mechanical seal and causes leakage.
To determine the cause, it’s necessary to know where the leak is occurring. There are many possible locations for leaks; it’s important to identify which one is leaking. The component in question needs to be taken apart to check whether there is deformation, corrosion, or gasification – each case requires a specific analysis
There is a high likelihood of damage to the sealing surface of the mechanical seal and resulting leakage, caused by crystallization that occurs when the alkaline solution precipitates at low temperatures; if the temperature of the alkaline solution is not high, it is recommended to turn off the cooling water. Or heat the seal box with steam when there is a leak to see if that improves things.
If the medium temperature is low, crystallization is likely to occur; DBM is not very suitable in this case. It might be better to try other types of mechanical seals such as C8 or C45. It’s advisable to use cemented carbide for the sealing surfaces. Alkali pumps leak easily due to crystallization
Alkaline solutions tend to crystallize, which can wear out the mechanical seal; therefore, the flushing method must be appropriate. It’s best to use PLAN62 as well