Centrifugal pump mechanical seal failure causes

1, the static ring sealing surface leakage
Main reasons are: face flatness, roughness does not meet the requirements, or surface scratches ; face between particulate matter , resulting in both ends of the surface can not be the same run ; installed in place , incorrectly.
2 , the compensation ring seal leak
Main reasons are: gland deformation, uneven preload ; installed incorrectly ; seals do not meet quality standards ; ring selection is wrong.
Actual results showed that most parts of the failure of the sealing element is dynamic and static ring end face mechanical seal centrifugal dynamic and static ring face is a common failure occurs cracking phenomenon for two main reasons :
① sealing surface when installing the gap is too big , too late to rinse away the heat generated by friction ; flushing fluid leakage from the sealing surface clearance to go , resulting in overheating and damage to the end face .
② liquid medium vapor expansion , so that both ends of the surface by the vapor expansion force to separate , when the two sealing surfaces when bonding force , resulting in destruction of the lubricating film facing surface overheating.
③ poor lubricating liquid medium , together with the operating pressure overload, the two sealing surfaces trace rotation is not synchronized. Such as high speed pump speed is 20445r/min, central diameter of the sealing surface 7cm, pump operation after the line speed up 75m / s, when there is a lag can not track the rotating sealing surface , the sealing surface is damaged resulting in instantaneous temperature .
④ sealing fluid orifice or filter is clogged , causing water shortage, so that the mechanical seal failure.
In addition , the sealing surface slippery surface ditch , face a gap of bonding lead to failure of the sealing element ,nylon cable ties two main reasons:
① dirty liquid medium , a small hard particles , people at high speed sliding sealing surface , the end surface scratches and failure.
② poor coaxial transmission parts pump , the pump is turned face each revolution is shaking friction once, moving ring running track misalignment , causing vaporization face , overheating wear.
③ liquid medium caused by the frequent occurrence of hydraulic characteristics of pump vibration , resulting in the sealing surface dislocation and failure.
The sealing element is a liquid medium corrosion, stress concentration , with soft and hard materials , erosion , secondary seal O-ring , V -ring , is not compatible with the liquid medium concave ring , deformation, surface damage can cause failure of the mechanical metal cable ties , so form of damage to its comprehensive analysis to identify the root cause , to ensure the long-running mechanical seals .