Monday, April 11, 2011

Failures and Unintended Component Applications

Extending the limits and the specification boundaries of components is common in innovative environments, as often a standard component does not exist yet for a new technology.  In this case, a pump designed to deliver low temperature liquids was used in an application due to its specified flow curve, operating pressures, and cost. The vendor specification did not

include a prescribed operating temperature. Vendor supplied reliability data was used in initial calculations and testing performed on the unit showed it to work well under higher temperature conditions. Pump_spring
Multiple systems were produced and several were deployed, all using the same pump.  After several weeks of near continuous system operation, the pumps began to fail. The failure mode was clear: broken springs. The vendor would not honor claims to the failures since the application was not as intended. Specifying a new pump was difficult due to limited space, tubing interface locations, and controls system changes. It was thought that a new spring design would correct the problem and a new material specification did extend the life of the pump. After working with the vendor and gaining a better understanding of the pump operation, an error in the controls design was found to cause extra stress on the springs.
If the pump had undergone a more rigorous test protocol in the lab under extreme use this failure may have been detected earlier. Many lost hours and customer perception issues may also been avoided. Finding a reason for a vendor to support an innovative application may not always be easy, but finding common ground and commitments to pursue continued use and partnerships with vendors may change their mind. A new spring material and a new controller design resulted in vendor opportunity to enter a new market.
When designing new systems, components may have special requirements that are not readily available. Any component that is not used for its intended purpose should be tracked and discussed in design reviews.

Blogger Labels: Pump,Applications,Case Study,Component,Failures

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