Sealing tips

Date:Jan 22, 2019

Mechanical seal scouring technology features

The purpose of the mechanical seal flushing is to prevent the accumulation of impurities, prevent the formation of the airbag, maintain and improve the lubrication, etc., and when the temperature of the flushing liquid is low, it has a cooling effect.

1, internal flushing

Positive flushing: Using the sealed medium of the working host, the outlet end of the pump is introduced into the sealed chamber through the pipeline. It is mainly used for cleaning fluid. When the temperature is high or there is impurity, a cooler, a filter, etc. may be arranged on the pipeline.

Backflushing: Using the sealed medium of the working host, the inlet end of the pump is introduced into the sealing chamber, and after flushing, it is returned to the pump inlet through the pipeline. The main purpose is to clean the fluid. The full flushing is to use the sealed medium of the working host, and the outlet end of the pump. The sealing cavity is introduced through the pipeline, and is flushed and then flows back to the pump inlet through the pipeline. This method is better in cooling effect.

2, external flushing: the introduction of the external system and the cleaning fluid compatible with the sealed medium to the sealed cavity for flushing. The external flushing fluid pressure should be 0.05--0.1 MPA larger than the sealed medium, and used in the case where the medium is high temperature or solid particles. The flow rate of the flushing liquid should be ensured to take away the heat, and it is necessary to satisfy the need of flushing, and there is no erosion of the seal. To do this, it is necessary to control the pressure of the sealed chamber and the flow rate of the flushing. The flow rate of the general cleaning scouring solution should be less than 5 M / S; the slurry liquid containing the particles must be less than 3 M / s, in order to achieve the above flow rate value, the scouring liquid and the sealed chamber The difference of pressure should be ≤0.5MPA, generally 0.05--0.1MPA, and 0.1--0.2MP for double-face mechanical seal. The position of the orifice into which the flushing liquid enters and exits the sealing chamber shall be placed around the sealing end face and shall be close to the moving ring side, in order to prevent the graphite ring from being eroded or the temperature difference deformation due to uneven cooling, and impurity accumulation and coking, etc. A tangential introduction or a multi-point flushing may be employed. If necessary, the flushing fluid may be hot water or steam.

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