The static rings of the front and rear machine seals of the multi-stage centrifugal pump are broken
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The front bearing of the motor began to smoke. After the electrician removed the motor and replaced the bearing, and after aligning the pump, it was started up; however, at that time the pump’s mechanical seal was leaking severely. Upon inspection by the fitter, it was found that the static rings on the front and back sides were broken. Yet no leakage from the mechanical seal was noticed when the motor was smoking. I hope colleagues from Chuan can provide more guidance
The motor disassembly process should not easily damage the mechanical seal. Was it the vibration of the main unit caused by damage to the motor bearings that led to the fragmentation of the static ring?
What are the reasons for the fracture of the static ring? 1. Temperature fluctuations cause material failure and resulting fragmentation. 2. Significant vibration during startup leads to intense collisions with the moving ring. 3. Quality issues with the stationary ring itself. What kind of pump is a multi-stage pump? Most of the multistage pumps we have here are high-temperature pumps, and we have encountered cases where the static ring exploded immediately after filling the pump without preheating. Was sufficient preheating done before starting the pump? Is there significant vibration during smoking of the motor bearings, and how does it affect the vibration of the pump body? Did the fitter check to ensure that the static ring was intact during the mechanical seal installation? The above are my own thoughts; the original poster can take them into consideration.
Was there no leakage from the mechanical seal at all before replacing the motor? Is the pump not vibrating?
At room temperature; the pressure of the pre-hydrogenation feed pump is 3.6 MPa, with a flow rate of 200 t/h
The pump had no leaks, but vibration levels could not be measured at that time; the pump was switched over urgently
I need to check the recent vibration conditions
Logically, the stationary ring should be thicker and more robust than the rotating ring; since it’s the rotating part that’s supposed to break, it should be the rotating ring that gets damaged. I don’t understand this.
I asked the equipment supervisor yesterday; because smoke was coming from the motor bearings, the operator stopped the pump right away without following the standard procedure of closing the outlet valve first. Since the pressure in this pump reached 4 MPa and the outlet check valve wasn’t functioning properly, high-pressure fluid flowed back into the pump, damaging the stationary ring
It’s not known what type of coupling is being used; if there’s no problem with the pump bearings, it’s almost certain that the equipment vibration was caused by a motor failure, which resulted in the static ring breaking. Of course, is there dry grinding?