Leakage in the mechanical seal of a centrifugal pump
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A regular centrifugal pump is used to transport tar, under negative pressure at a temperature of 90 degrees. The original dry gas seal was removed, and now a mechanical seal is being used; however, it leaks severely after just over a month of use. The manufacturer was called in for analysis, and it was found that there were dry cracks on the seal, likely due to poor backwashing performance. I’m not sure if there are other reasons; originally, it was specified that the machine seal should last for one year under normal conditions.
It’s caused by the operating conditions; we also have many pumps for such media at different temperatures
What was said upstairs is correct – vacuum-type mechanical seals tend to get emptied of air. We’ve encountered this issue before as well; we should discuss it in detail with the manufacturer to see if there are any ways to improve it
In cases of negative pressure, when the backwash volume is low, the backwashing effect is reduced, which leads to dry grinding and wear of the sealing surfaces. Nowadays, silicon carbide and cemented carbide are generally used together. Check again to see if there are any issues with the fit of the O-rings
There’s no need for rinsing; try the direct quenching method using steam or hot water – we’ve tried it on ethylene tar!
Modified to pressure-bearing double-end face type, with storage tank
Thank you all; next, we will make improvements based on the information you provided. Negative pressure twelve kilopascals a
Try thickening the backwash pipeline first; if that doesn’t work, then consider replacing the machine seal
Why not use a dry gas seal with two faces, since the flow rate is very low?
This post was last edited by Zhongheng Pump Industry on 2020-2-26 at 09:10; it’s probably caused by negative pressure. Change the material of the sealing friction pair. Try using silicon carbide on graphite.