What did GE's analytics software find?
In January, GE's Mine Performance solution detected a difference in flow measurement and set point on the loop for water flow to the mill sump. The set point fluctuated between 0 and 2000 m3/h, yet the process variable remained at 500 m3/h regardless of the control signal to the valve. GE’s Industrial Performance & Reliability Center (IPRC) reported the issue to the customer for discussion on the weekly call.
What was the underlying cause?
Upon investigation, the customer learned that the magnetic coupling of the control valve was degraded.
What was the value to the customer?
Due to the early notification by the IPRC, the customer was able to resolve the issue before a lost opportunity event occurred. Loss of level control in the sump can lead to overflows and the spillage of raw material. The sump water also controls the density of the material, which directly controls the energy consumption and efficiency of the process.
1) The process variable does not follow the set point as it is changed over time prior to valve maintenance but closely follows the setpoint post-maintenance. 2) Control loop performance clearly improves to the target limit after the valve is repaired.