The purpose of flushing is to prevent impurity accumulation, prevent airbag formation, maintain and improve lubrication, and when cooling fluid is low, it has cooling effect. The main ways of washing are as follows:
1. Internal flushing
1.1. positive flushing
Features: using the sealed medium of the working host, the pump's outlet end is introduced into the sealing cavity through the pipeline.
Features: using the sealed medium of the working host, the pump's outlet end is introduced into the sealing cavity, and then rinsed and then flows back through the pipeline to the pump inlet.
1.3. Full flush
Features: using the sealed medium of the working host, the pump's outlet end is introduced into the sealing cavity through the pipeline, and then rinsed and then flows back to the pump inlet through the pipe.
2. External Flushing
Features: introducing the clean fluid compatible with the external system to the sealed cavity for washing.
Application: the pressure of the external rinsing fluid should be 0.05--0.1MPa larger than that of the sealed medium. It is suitable for occasions where the medium is high temperature or solid particles. The flow rate of the rinsing fluid should ensure that the heat is taken away, and the need for flushing is not satisfied. Therefore, it is necessary to control the pressure of the sealing cavity and the flow velocity of flushing. The flow velocity of the general cleaning liquid should be less than 5m/s, and the slurry containing particles must be less than 3m/s. In order to reach the above flow rate, the difference between the pressure of the washing liquid and the seal cavity should be <0.5MPa, and the 0.05--0.1MPa is generally taken, and the double cartridge mechanical
seal is advisable to 0.1--0.2MP.The entrance and exit of the sealing cavity should be located near the seal face and near the moving ring side. In order to prevent the graphite ring from erosion or the temperature difference caused by the uneven cooling, and the accumulation and coking of the impurities, it can be introduced by tangential or multi point flushing.