Hazard Monitors for Grain Elevators


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Hazard Monitors for Grain Elevators

  1. 1. Johnny WheatBrian Knapp4BComponentsLimitedPRESENTED BY:Copyright 2012 © 4B Components Ltd. All Rights Reserved
  2. 2. Combustible Dust(Fuel)Dispersionof Dust ParticlesIgnition Source(Heat)Confinementof the Dust CloudOxygen in Air(Oxidizer)YOUR PROBLEM: Grain dust is explosiveYOUR SOLUTION: Remove one of the elements fromthe dust explosion pentagonCopyright 2012 © 4B Components Ltd. All Rights Reserved
  3. 3. Common Ignition Sources:1. Belt Slip2. Belt Misalignment3. Hot BearingsCopyright 2012 © 4B Components Ltd. All Rights Reserved
  4. 4. If you eliminate these ignition sources then you not onlyconsiderably reduce your chance of having anexplosion, but you also realize every day values of:1. Improved Preventative Maintenance2. Smoother Running Equipment3. Longer Service Life for EquipmentCopyright 2012 © 4B Components Ltd. All Rights Reserved
  5. 5. YOUR PROBLEM: Belts slipping on the head or drive pulley of amachine is an ignition sourceYOUR SOLUTION: Install a speed switch at the tail end of the bucketelevator or conveyor to warn when the belt startsto slip and automatically stop the machineSensorM800 Elite Speed SwitchCopyright 2012 © 4B Components Ltd. All Rights Reserved
  6. 6. Standard 1910.272(q)(5)The employer shall equip bucket elevators with a motion detectiondevice which will shut-down the bucket elevator when the belt speedis reduced by no more than 20% of the normal operating speed.Copyright 2012 © 4B Components Ltd. All Rights Reserved
  7. 7. YOUR PROBLEM: Belts misaligning and rubbing against a machine’scasing is an ignition sourceYOUR SOLUTION: Install belt misalignment sensors at the drive andtail ends of the bucket elevator to warn when thebelt starts to rub and automatically stop the machineSensorSensorTouchswitchCopyright 2012 © 4B Components Ltd. All Rights Reserved
  8. 8. Standards 1910.272(q)(6)(i) & (q)(6)(ii)Equip bucket elevators with a belt alignment monitoring device which willinitiate an alarm to employees when the belt is not tracking properly.Copyright 2012 © 4B Components Ltd. All Rights Reserved
  9. 9. YOUR PROBLEM: Bearings overheating are ignition sourcesYOUR SOLUTION: Install bearing temperature sensors on all criticalbearings such as the drive and tail bearings to warnwhen a bearing reaches a high temperature andautomatically stop the machineSensorSensorADB Bearing Temperature SensorCopyright 2012 © 4B Components Ltd. All Rights Reserved
  10. 10. Standard 1910.272(q)(4)(ii)Provide vibration monitoring, temperature monitoring, or other meansto monitor the condition of those bearings mounted inside or partiallyinside the leg casing.Copyright 2012 © 4B Components Ltd. All Rights Reserved
  11. 11. YOUR PROBLEM: Electrical equipment can itself, be an ignitionsource for a grain dust explosionYOUR SOLUTION: Only install equipment approved / listed andcertified by an NRTL (Nationally RecognizedTesting Laboratory)Class II Division 1 Group G -• For example, inside a bucket elevator or belt conveyorClass II Division 2 Group G -• For example, outside a bucket elevator or belt conveyorCopyright 2012 © 4B Components Ltd. All Rights Reserved
  12. 12. YOUR PROBLEM: You are not confident that your local electricalservice supplier has the experience and knowledgerequired to professionally install a hazard monitoringsystemYOUR SOLUTION: 1. Send your electrician to the manufacturersfacility for training on the equipment to be installed2. Have the manufacturer install the system orrecommend a suitable installerCopyright 2012 © 4B Components Ltd. All Rights Reserved
  13. 13. YOUR PROBLEM: Operators continue to operate equipment despitehazard monitoring systems indicating that there isa hazardous conditionYOUR SOLUTION: 1. Educate operators on the hazards of grain dustexplosions2. Instruct operators of the severe penalties thatwill be enforced if they do not follow companypolicy3. Automatically log all alarms and shutdowns sothat operators understand that there is apermanent record and they are accountableCopyright 2012 © 4B Components Ltd. All Rights Reserved
  14. 14. YOUR PROBLEM: Equipment does not perform to your expectationsYOUR SOLUTION: 1. Inspect the system and installation2. Commission the system3. Test the system, both initially and periodically4. Train the operators and management on thecapabilities, use, maintenance and testing of thesystemCopyright 2012 © 4B Components Ltd. All Rights Reserved
  15. 15. YOUR PROBLEM: A sensor or control is damaged and the only wayto run equipment is by electrically bypassing thehazard monitoring systemYOUR SOLUTION: DO NOT RUN IN BYPASS. Have spare sensorsand components available for immediatereplacement so that down time is reduced to aminimum! ! ! WARNING ! ! !Copyright 2012 © 4B Components Ltd. All Rights Reserved
  16. 16. Standard 1910.272 App AIt is imperative that the prearranged schedule of maintenance beadhered to regardless of other facility constraints. The employershould give priority to the maintenance or repair work associated withsafety control equipment…(See Actual Standard For Full Interpretation)Copyright 2012 © 4B Components Ltd. All Rights Reserved
  17. 17. YOUR PROBLEM: 1. OSHA has stepped up its facility inspection andaudits in conjunction with their National EmphasisProgram (NEP) on dust explosions2. OSHA is finding twice as many violations inrelation to the NEP inspections compared with allother types of facilities. One such violation is thatbucket elevators and conveyors are not equippedwith bearing temperature, belt alignment andunderspeed detection monitorsYOUR SOLUTION: 1. Understand the dangers of grain dust, andimplement a program of compliance to not onlyOSHA regulations, but also NFPA and otherstandards2. Install hazard monitors (as discussed earlier) tohelp eliminate ignition sourcesCopyright 2012 © 4B Components Ltd. All Rights Reserved
  18. 18. OSHA & NFPA STANDARDS(See Actual Standard For Full Interpretation: OSHA 1910-272, NFPA 61, NFPA 654)Hazard RequirementBelt Slip Motion detection device to provide a shutdown andalarm at 20% reduction in normal belt speed. Alsoshutdown of feeding equipment.Belt Misalignment Belt alignment monitoring devices at head and tailpulleys, which initiate an alarm.Bearing Failure Bearing temperature or bearing vibration monitors whichactivate and alarm.Pulley Misalignment Head pulley alignment monitors which activate an alarm.Plugged Spout Sensors which provide a shutdown and alarm when thereis a plug condition. Also shutdown of feeding equipment.Copyright 2012 © 4B Components Ltd. All Rights Reserved
  19. 19. o NFPA 61 Standard for agricultural and foodprocessing industry (rev. 2008)o NFPA 68 explosion venting standard (rev. 2007)o NFPA 69 prevention standard (rev. 2008)o NFPA 70 NEC (rev. 2008)o NFPA 77 static electricity (rev. 2007)o NFPA 499 guide to combustible dust areaclassifications (rev. 2004)o NFPA 654 standard for general industry (rev. 2006)NFPA STANDARDSCopyright 2012 © 4B Components Ltd. All Rights Reserved
  20. 20. TYPICAL SENSORS FOR HAZARD MONITORINGSpeed &Belt SlippageBelt MisalignmentBearingTemperatureCopyright 2012 © 4B Components Ltd. All Rights Reserved
  21. 21. TYPICAL CONTROLS FOR HAZARD MONITORINGWatchdog™ EliteSingle MachineHazard MonitorPLC T500 Hotbus™Multi MachineHazard MonitorCopyright 2012 © 4B Components Ltd. All Rights Reserved
  22. 22. QUESTIONS?Copyright 2012 © 4B Components Ltd. All Rights Reserved
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