Centrifugal pump shutdown is mainly caused by the failure of the mechanical seal. Failure of the performance of most of the leakage, the reasons for the following leakage:
① static and dynamic ring seal surface leakage, the main reasons are: the end plane flatness, roughness did not meet the requirements, or surface scratches; between the end of a particulate matter, resulting in both ends can not run the same; installation is not in place, the way is not correct.
② compensation ring seal leakage, the main reasons are: gland deformation, preload is not uniform; installation is not correct; seal quality does not meet the standard; seal selection is wrong.
The actual use of the results show that the most failed parts of the sealing element is moving and static ring of the end, centrifugal pump sealing, static ring end of the crack is a common failure phenomenon, the main reasons are: ① installation sealing surface gap is too large, The rinse liquid is too late to take away the heat generated by the friction pair; the flushing fluid leaks away from the sealing surface gap, causing the end face to overheat and damage.
② liquid media vaporization expansion, so that both ends by the vaporization of expansion force and separated, when the two sealing surface forced fit, damage the lubricating film and thus cause the surface of the surface overheating.
③ poor liquid media lubrication, coupled with the operating pressure overload, two sealed surface tracking rotation is not synchronized. For example, the high speed pump speed is 20445r / min, the sealing surface center diameter is 7cm, the pump speed after the line speed up to 75m / s, when there is a sealing surface lag can not track rotation, instantaneous high temperature caused by sealing surface damage.