Bearing monitoring on underground conveyors. Clement Matshavha Junior Engineer 24 April 2013

Transcription

1 Bearing monitoring on underground conveyors Clement Matshavha Junior Engineer 24 April 2013

2 Contents Purpose of monitoring bearing temperature on underground (UG) conveyors Exposure risk to UG fires Current controls Identified gap in our controls System functionality Advantages of monitoring bearing temperature Technical challenges Current status of installation progress Number of trips Slide 2

3 Purpose of monitoring bearing temperature on UG conveyors The temperature of a failed bearing can rise high enough to ignite the lubricant and cause an underground fires Dangers of underground fires: They produce toxic gases into the ventilation system They damage equipment and machinery Source: GLD Slide 3

4 Exposure risk to UG fires Khutala uses approximately 80km of conveyor belts to transport coal from the 14 sections to the surface In the massive conveyor installation there are approximately 950 pulley bearings. Any failed pulley bearing can be a source of an excessive hot surface which can start an underground fire Source: GLD Slide 4

5 Current controls for prevention Current controls for the prevention of fire and explosion Smoke sensors Stone dust Fire extinguishers Water stations Ventilation Gas testing instruments Fire retardant belts Source: GLD Slide 5

6 Current controls for monitoring the bearings Current controls for monitoring bearings Weekly inspections Monthly maintenance Monthly condition monitoring Source: GLD Slide 6

7 Identified gap in our control Identified gap Faulty bearings cannot be identified immediately, they can only be identified during weekly inspections, monthly maintenance and condition monitoring. Solution tried to fill the gap Bimetal sensor used to monitor the temperature of pulley bearings System was not successful because it did not give an early warning for potential bearing failure and did not identify precisely which bearing failed System currently used to fill the gap Online bearing temperature monitoring system. The system uses Resistance Temperature Detector (pt100) sensor to continuously monitor the bearing temperature. Slide 7

8 System Functionality TRD Probes (PT100) SCADA TRD Card PLC Server Room Slide 8

9 Bearing temperature on the SCADA Slide 9

10 Starting up a conveyor Slide 10

11 Advantages of monitoring bearing temperature Should any bearing reach 50 C, it will set off an alarm in the Control Room, and when it reaches 60 C the conveyor will be stopped Bearing temperature will be monitored continuously (online) Prevent possible fires when high temperatures are generated from bearing failures Early detection of potential bearing failures Prevent possible downtime and production loss through early detection on bearing malfunctioning History of temperatures will be available Slide 11

12 Technical challenges 1. Mounting the RTD probes onto the bearings of the take-up pulley. When the take-up pulley moves back and forth, the cable connecting the RTD probe to the RTD card is frequently damaged. Proposed solution Feed the cable from the RTD card to the probe through a cable reel. 2. Installing the monitoring system on the mobile drives because the system is not flameproof. Slide 12

13 Current status of installation progress Actual number of Drives Number of Drives Installed # Trunk Con. 2 # Mobile Con. 4# Trunk Con. 4# mobile Con. Slide 13

14 Number of Trips # 4# Number of Trips in the Month of Feb (2013) Slide 14

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