High-temperature pump mechanical seal
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The mechanical seal used for the residue oil pumps in our factory is a DBM65 diaphragm mechanical seal; the temperature of the medium is around 350 degrees. Dan Dong Klon seals are used here. During operation, there is a cracking sound, similar to the sound heard when cooking at home once the oil is added to the pan. There are oil droplets in the cooling water, which is likely due to seal leakage and the resulting noise. The manufacturer’s staff said that the high temperature is the cause, but I’ve used seals from other companies before without encountering such problems. Could it be that the issue lies with the quality of the seal, or was there something wrong during the installation process? I would appreciate your advice!
Residual oil has high viscosity; it can still be used even if there is little leakage, so monitor it regularly； Mechanical seals operate under harsh conditions; judging from this situation, leakage from the friction pair has seeped into the cooling water ；
Let’s start by checking for installation issues; the noise is likely caused by the high-temperature medium leaking and coming into contact with water. We use clones here as well, and no issues have been encountered so far.
First, it is necessary to check whether the properties of the materials produced meet the requirements for use in pumps, such as the wear caused by impurities.
A bellows mechanical seal is also used. What flushing protocol should be used? It is not necessarily a leak in the mechanical seal; it’s possible that the flushing oil has entered the steam stream, resulting in oil droplets appearing in the cooling system.
Previously, when we looked at the Fuchs centrifugal pumps used in Germany and the United States for pumping oil residues in refineries, they all employed mechanical seals. Tianjin John Clone and currently Dandong Sealing. Factors that affect the sealing performance includes the pump’s design (the user shall provide detailed operating instructions and conditions), installation, and pre-use inspection. It’s hard to say much about the installation techniques in some areas of the country. I’ve seen it changed a few times; it’s far inferior to the foreign versions.
It is preferable to use PLAN32+62 for the residue pump; 32+52/53 and similar types can also be used, as they can provide clean seal oil for the mechanical seal. If there is a popping sound inside the pump, it may be suffering from cavitation; check whether the filter at the pump’s inlet is clogged.
Flushing is carried out directly from the pump outlet to the mechanical seal gland via a flushing pipe, with cooling water used for cooling as well!
It worked fine before. I asked my former colleagues, and they said they encountered the same issue; replacing the machine seal resolved it. Also, the shaft sleeve gasket for the machine seal is a 1-millimeter aluminum gasket with a narrow sealing surface – could it be that leakage is caused by this gasket?
There are too few conditions, so it seems there are many possibilities~~~~ The 53a+62 (steam) option should be a good choice~~~ Oil leakage is most likely not due to a leak in the sealed friction pair; it might be caused by high temperatures and vibration, which result in oil seeping out from behind the O-ring of the stationary ring, and then that oil is carried away by 62~~~