A Chemical industry operator was experiencing repetitive failures with a lobe pump.
The pump was failing every few months due to mechanical seal damage. In these instances identifying the root cause of the failure is critical to resolving the problem and performance testing is an integral part of this alongside understanding the application and duty in which the pump is operating.
Replicating the duty and performance of the machine offsite is necessary in order to eliminate site conditions and therefore testing is a critical aspect in the investigations and before any repairs, refurbishments or modifications undertaken. Initial testing can be performed in order to replicate the customer’s reported fault, it can determine the Root Cause Failure (RCFA) and its efficiency can be measured and compared to that of the Original Equipment Manufacturers (OEM) test certificate.
On this specific occasion the problem was traced back to a setup on the application, there was a build-up of pressure in the system due to several pumps working in parallel. After analysing the setup and the failures, it was found that during sequencing switch over of the pumps there was a pressure build up which, in turn, caused premature mechanical seal failures.
After replacing the mechanical seal as part of the refurbishment process the pump was again tested to ensure it was performing to the OEM standard. Modifications were performed on site and a pressure relief system installed to prevent the seal failure. This intervention achieved the objectives of reducing production downtime, saving on maintenance hours removing and refitting replacement seals and repair cost savings by extending the MTBR. Added benefits associated with reducing energy consumption were also experienced.
It also reinforces the confidence that the repair has been tested, is operating safely and meets production needs for reliability and performance while saving £42,350 per year.