Mechanical seal normal operation and maintenance problems

1. Preparation and precautions before starting


1) Check the mechanical seal, as well as the installation of auxiliary devices and pipelines, and meet the technical requirements;


2) Perform a static pressure test before starting the mechanical seal to check whether the mechanical seal is leaking. If there are many leaks, the cause should be investigated and eliminated. If it is still invalid, it should be disassembled for inspection and reinstalled. The general static pressure test pressure is 2~3 kg/cm2;


3) Press the pump to turn the bar to check whether it is light and even. If the barring machine is difficult or does not move, you should check whether the assembly size is wrong and whether the installation is reasonable.


2. Installation and shutdown


1) Keep the sealed cavity filled with liquid before starting. For the delivery of solidified media, steam should be used to heat the sealed cavity to melt the media. It must be cranked before starting to prevent the soft ring from breaking due to sudden start;


2) For the mechanical seal using the pump oil seal system, the oil seal system should be started first. Stop the oil sealing system after stopping;


3) After the hot oil pump is shut down, the cooling water in the oil seal chamber and the end face seal cannot be stopped immediately. The cooling water can be stopped only when the oil temperature at the end face seal drops below 80 degrees, so as not to damage the seal parts.


3. Operation


1) If there is a slight leak after the pump is started, it should be observed for a period of time. If the leakage is still not reduced for 4 hours of continuous operation, the pump should be stopped and checked;


2) The operating pressure of the pump should be stable, and the pressure fluctuation should not exceed 1 kg/cm2;


3) During the operation of the pump, the phenomenon of evacuation should be avoided to avoid dry friction of the sealing surface and damage to the seal;


4) The sealing condition should be checked frequently. During operation, when the leakage exceeds the standard, the heavy oil is not more than 5 drops/minute, and the light oil is not more than 10/minute. If there is no improvement trend within 2-3 days, the pump should be stopped to check the sealing device.