Modification of the mechanical seal in centrifugal pumps
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Centrifugal pumps are the most widely used pumps in chemical production, and mechanical seals are the primary sealing method for such pumps. Our factory has several centrifugal pumps; the medium in these pumps has a high temperature and high concentration. The mechanical seals used are self-priming, and they tend to fail frequently – sometimes the mechanical seals need to be replaced three times a week. Later, the mechanical seal was changed from self-flushing to appropriate external flushing water; now, the seal has been in operation for half a year with no abnormalities observed. If anyone has good methods, let’s learn together and make progress together!
Changing to a packing seal makes maintenance more convenient.
For centrifugal pumps, high-pressure sealing water generally provides the best sealing effect. Our unit has been using it for a year with no problems; the pump operates at a pressure of 7.5 MPa and a temperature of 245 degrees
It must be related to the medium being transported! If the medium contains particles or other impurities, it probably cannot achieve self-sealing.
Generally, sealed flushing methods include self-flushing, cyclic flushing, and external flushing; the appropriate method should be selected based on the properties of the medium and the conditions of the factory
The medium used in self-priming pumps must meet certain conditions: the temperature cannot be too high, and the concentration cannot be too high. It is preferable to use externally flushed pumps when such conditions are available. Our unit has several pumps for high-temperature ethylamine hydrochloride that are self-priming as well, and we need to plan to replace them
The centrifugal pumps here (used for circulating water containing particles) use oil seals, which need to be replaced every 2 months!
If a tandem mechanical seal would work as well, our plant uses tandem mechanical seals for the pumps at the bottom of the vacuum distillation tower.