What are the reasons why the pump cover and shaft of plastic-lined centrifugal pumps, as well as mechanical seals, often get damaged?
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Sea friends: The lined centrifugal pumps used in our facility for hydrochloric acid absorption often cause damage to the mechanical seals, pump shafts, and rear covers. Why is that? The process is: hydrochloric acid storage tank ----- plastic-lined centrifugal pump ----- graphite heat exchanger ----- hydrochloric acid storage tank. When the pump cover was opened, there was something black inside the pump chamber; it should be graphite. My preliminary assumption is that the graphite from the graphite heat exchanger has fallen off, causing graphite particles to rub against the friction surface of the mechanical seal and thus damaging it. I would appreciate any opinions from experts to help resolve this issue
Graphite heat exchangers generally do not fall off. Our company has over 50 graphite heat exchangers of various specifications, and we have never encountered such a situation. The mechanical seal of the centrifugal pump has burned out. Apart from assembly-related issues, we need to check whether there is a problem with the supply of material. Our units are lined with fluoropolymer, and the mechanical seals used are made of SIC+PTFE. The process is similar to yours; the situation you described occurs very rarely. When the mechanical seal burns out, adjustments to the liquid level display are caused by a shortage of material.
There’s no issue with liquid interruption, but for some reason, it gets overheated frequently, which is troubling
The reasons for the burnout of mechanical seals include pump cavitation and excessive sealing compression
Reply to 4# heyan919: The mechanical seal does not have cooling water
If the above reasons are ruled out, it is either 1: assembly issues, such as excessive tightness; or 2: the use of a hard-on-hard end-face friction pair