Equipment Isolation System

Abstract

An equipment isolation system (10) comprising at least one equipment item (20,21,25) energisable by an energy source (30) and a control system (50,260) for automatically isolating said at least one equipment item (20,21,25) from said energy source (30) to an isolated state, wherein said equipment isolation system (10) includes means for securing the integrity of operation of said equipment isolation system, said securing means (21A,25A,50,S,900) including at least one monitoring means (50,S,900) for continuously monitoring the isolation state of said at least one equipment item (20,21,25) through detection of undesired energy flow or possible energy flow therein.

Claims

1. An equipment isolation system comprising: at least one equipment item energisable by an energy source; and a control system for automatically isolating said at least one equipment item from said energy source to an isolated state, wherein said equipment isolation system includes means for securing the integrity of operation of said equipment isolation system, said securing means including at least one monitoring means for continuously monitoring the isolation state of said at least one equipment item through detection of undesired energy flow or possible energy flow therein.

2. An equipment isolation system as claimed in claim 1 wherein said monitoring means operates prior to an isolation being effected to ensure that all energy which could potentially cause a safety hazard is dissipated from the equipment item.

3. An equipment isolation system as claimed in claim 1 wherein each said monitoring means operates during an isolation to ensure the integrity of the isolation is not compromised once it has been instigated.

4. An equipment isolation system as claimed in claim 1 wherein a plurality of monitoring means are selected, preferably following a hazards analysis, to address at least any substantial threats to the integrity of the isolation system.

5. An equipment isolation system as claimed in claim 1 wherein at least one monitoring means operates independently of another.

6. An equipment isolation system as claimed in claim 1 wherein said securing means forms part of the control system, said securing means preferably including one or more electronic, mechanical or electro-mechanical device(s) for monitoring important components of the equipment isolation system.

7. An equipment isolation system as claimed in claim 6 wherein said monitoring device(s) provide a signal to the control system representative of a hazard to the integrity of the equipment isolation system.

8. An equipment isolation system as claimed in claim 7 wherein sensors are used to monitor the equipment isolation system providing signals indicating tampering, failure of, or other threats to, the integrity of the equipment isolation system.

9. An equipment isolation system as claimed in claim 1 wherein the securing means forms part of the equipment item being isolated and is operated as part of the isolation process.

10. An equipment isolation system as claimed in claim 1 wherein each said monitoring means includes a sensor, preferably a plurality of sensors, for detecting and/or monitoring undesired energy flow or possible energy flow in the equipment item.

11. An equipment isolation system as claimed in claim 10 wherein a sensor is selected from the group consisting of movement sensors, speed sensors, proximity sensors, voltage sensors, current sensors, temperature sensors, flow sensors and pressure sensors.

12. An equipment isolation system as claimed in claim 1 wherein said equipment item includes a conveyor belt system and said equipment isolation system implements steps to dissipate energy from the isolated, or to be isolated, conveyor belt system through stored energy tests prior to isolation.

13. An equipment isolation system as claimed in claim 1 wherein said equipment item is a conveyor belt system and said control system continuously monitors conveyor belt movement.

14. An equipment isolation system as claimed in claim 12 wherein said conveyor belt system includes a braking system with brake(s) for slowing and stopping conveyor belt movement, said brake(s) being released and applied in a braking cycle procedure during which the conveyor belt is continuously monitored for movement through stored energy testing employing at least one sensor, and preferably a plurality of sensors, until the control system confirms that hazardous stored energy has been released or dissipated, preferably by confirming that the conveyor belt is completely stationary.

15. An equipment isolation system as claimed in claim 12 wherein said at least one sensor, and preferably a plurality of sensors, is selected from the group consisting of belt speed sensors, belt standstill monitors, belt slack monitors, belt clamp position sensors, braking system temperature sensors and braking system pressure sensors including brake fluid pressure sensors and brake fluid temperature sensors.

16. An equipment isolation system as claimed in claim 1 enabling purposeful continuation of energy supply to selected equipment items where authorised by the control system.

17. An equipment isolation system as claimed in claim 16 wherein said equipment item is a conveyor belt system and an energy supply is maintained to the conveyor braking system to ensure that braking action is applied as required during an isolation or energy dissipation process.

18. An equipment isolation system as claimed in claim 1 wherein said control system approves isolation on permissible request logged by an operator at a remote isolation station.

19. An equipment isolation system as claimed in claim 1 comprising at least one isolation switch movable between a first position in which an equipment item is energised by an energy source and a second isolated position in which the equipment item is isolated from the energy source, and a locking device co-operates with the switch for locking it into said isolated position in a lockout process wherein the position of the locking device is monitored by sensors and the control system for correct positioning whether for isolated and de-isolated states when using the equipment isolation system.

20. An equipment isolation system as claimed in claim 19 wherein sensors, such as proximity sensors, are provided to monitor for tampering with a locked out isolation switch.

21. An equipment isolation system as claimed in claim 1 including at least one remote isolation station including a control panel to implement and monitor isolation procedures, the control panel being protected by an enclosure with a lockable door enabling access to important components of the isolation system wherein the enclosure is provided with perimeter security monitoring means that detect unauthorised attempts to access or tamper with the enclosure by force.

22. An equipment isolation system as claimed in claim 9 wherein said at least one equipment item includes a conveyor belt system and said securing means includes at least one of belt clamps and shuttle locking pins, engagement of said securing means being instructed and confirmed by the control system.

23. An equipment isolation system as claimed in claim 1 wherein the equipment item is transferred from a de-isolated (energised) state, to an isolated state where it is isolated from said energy source and continuous monitoring of the isolated state occurs, and back to a de-isolated (energised) state.

Description

[0033] The equipment isolation system may be more fully understood from the following description of preferred embodiments thereof made with reference to the following drawings in which:

[0034] FIG. 1 shows a schematic layout of an equipment isolation system as applied to a conveyor belt system for which isolation integrity is monitored in accordance with preferred embodiments of the present invention.

[0035] FIG. 2 shows a schematic diagram of the exterior of a remote isolation station configured to implement the equipment isolation system of FIG. 1.

[0036] FIG. 3 shows a control panel provided inside the remote isolation station of FIG. 2 with the conveyor belt system in a normal state.

[0037] FIG. 4 shows an isolation lockout switch box used in the control panel of FIG. 3 and showing the isolation lockout switch in isolation lockout condition.

[0038] FIG. 5 provides a plot showing braking action for the conveyor belt system of FIG. 1 prior to isolation by the equipment isolation system shown in FIG. 1.

[0039] FIG. 6 shows a block diagram showing integration of mechanical security means, in the form of conveyor belt clamps, with a remote isolation station as shown in FIG. 2, for the conveyor belt system of FIG. 1.

[0040] FIG. 7 shows a schematic view of an automated conveyor belt clamp system for use in the equipment isolation system shown in FIGS. 1 and 5.

[0041] FIG. 8 shows a schematic view of a conveyor belt standstill monitor forming part of the conveyor belt system shown in FIGS. 1, 6 and 7.

[0042] FIG. 9 shows a schematic view of a shuttle conveyor forming part of the conveyor belt system shown in FIG. 1 and including mechanical security means in the form of shuttle locking pins.

[0043] Referring to FIG. 1, there is shown a schematic layout of a remote equipment isolation system 10, as retrofitted to an existing conveyor belt system 20, for example a long range conveyor system for conveying iron ore from a mine site to a port for shipment. The conveyor belt system 20 comprises a troughed conveyor belt 21 feeding a shuttle conveyor system 25 described further below with reference to FIG. 9. Conveyor belt 21 has a head pulley motor 22 driven by an electrical supply emanating from electrical contacts 31, whether provided as contactors or circuit breakers. One contact is a standard contactor for ON/OFF operation of the motor 22. The head pulley motor 22 is powered through a Variable Speed Drive (VSD) which is electrically powered from a 3 phase AC power supply line 23 providing voltages of less than 1000V AC. The electrical power is supplied from a sub-station 30. The sub-station 30 houses the contacts 31. Activation of the contacts 31 (i.e. placing them in the off or break state), de-energises all 3 phases of the electrical supply to the conveyor head pulley drive motor 22. Conveyor speed is sensed by a belt movement monitor 900 as will be discussed later with reference to FIG. 8. Such de-energisation is continuously monitored by a voltage monitor relay (not shown) located downstream of contacts 31, i.e. on the conveyor belt system 20 side of the contacts 31.

[0044] The conveyor belt system 20 also includes a Tramp Metal Detector (TMD) 21B for detecting tramp metal which requires removal to avoid damage to the conveyor belt 21. Prior to removal of tramp metal, the conveyor belt system 20 requires isolation, as described below, to make removal safer.

[0045] The conveyor belt system 20 and sub-station 30 are under the control and supervision of a plant control system 260 having a CCR (Central Control Room) 40, via a DCS (Distributed Control System), PLC (Programmable Logic Controller) and SCADA (Supervisory Control and Data Acquisition System) as are commonly used and would be well understood by the skilled person. Item 41 in FIG. 1 is representative of a communication and control network between the CCR and the various other plant and isolation systems and components. A Control Room Operator (CRO) 42 is located within the CCR 40 and has various input/output (I/O) devices and displays available for the proper supervision and control of the conveyor belt system 20. Except for the remote isolation system 10, the above description represents a conventional system as would be known within the materials handling and mining industries.

[0046] The remote isolation system 10 comprises fixed remote isolation stations 12 and 14 which are located proximate to the conveyor belt system 20. As will be evident from FIGS. 3 and 4, remote isolation stations 12 and 14 include control panels 700 for use in operating the remote isolation system 10. Each control panel 700 is integrated with a dedicated isolation switch box 200 and isolation lockout switch 400 for completing isolation of conveyor belt system 20 as described below. It will be understood that remote isolation stations 12 and 14 could be replaced or supplemented by one or more mobile isolation stations, for example in the form of portable computer devices (in certain applications these potentially being provided as smartphones) or communication devices using wireless communications, as disclosed for example in the Applicant's Australian Provisional Patent Application Nos. 2015902561 and 2015902562, the contents of which are incorporated herein by way of reference. The remote isolation stations 12 and 14 may be powered from the plant grid, other power networks or alternative power sources, conveniently such as via solar power.

[0047] The remote isolation system 10 also includes a master controller 50 incorporating a Human/Machine Interface (HMI) in the form of a touch sensitive screen 51 which displays human interpretable information. The master controller 50 is also located within sub-station 30. Remote isolation stations 12 and 14 are in communication with the master controller 50 and each other via communication channels such as channels 11 and 13. These communication channels can be provided in any suitable form including hard wired or wireless forms that satisfy known industrial open communication protocols with Ethernet communications being particularly preferred to enable flexible system updating. Communications must be via safety rated communications protocol software, noting that these may be varied depending on the PLC platform used. For example, the Interbus Safety or PROFIsafe software solutions provide an indication of existing systems which are well known within the mining and materials handling industries. This will ensure that the communication channels are monitored and diagnostic tools are available for fault control and rectification when required.

[0048] Further description of the electrical layout and operation of the remote isolation system 10 is provided in the Applicants granted Australian Patent No. 2010310881, the contents of which are incorporated herein by way of reference.

[0049] In summary, the conveyor belt system 20 is isolated, following tripping of the Tramp Metal Detector (TMD) 21B by tramp metal, by a process involving: [0050] An operator request at remote isolation station 12 or 14 for the control system to approve isolation of all or part of the conveyor belt system 20 including conveyor belt 21 and drive motor 22 in accordance with a preferred mode of isolation developed by the Applicant and described in Australian Provisional Patent Application No. 2015902558, the contents of which are incorporated herein by way of reference; [0051] Isolation being approved if the operator request meets permissives for isolation, for example as described in the Applicant's Australian Patent No. 2010310881; [0052] A try start process being invoked to check that the isolation is effective, which involves checking that electrical contacts for the conveyor belt system 20 are in an isolated position with no voltage being detected by the voltage monitor relay downstream of the electrical contacts 31 (and desirably, conveyor belt movement sensors such as movement speed sensor S and/or belt standstill monitor 900 confirming that the conveyor belt 21 has come to a complete stop as described below); an attempt to re-start the conveyor belt system 20 using try step button 780 or an automated process; and checking that there is no re-energisation of conveyor belt system 20 using the same sensors; and [0053] Lockout at a control panel of remote isolation station 12 and/or 14, with the isolation lockout switch 400 of isolation switch box 200 as shown in FIG. 4, if the try start process is unsuccessful (as required) and stored energy tests show that, for all practical safety purposes, energy has been dissipated from the conveyor belt system 20 and the remote isolation system 10 can proceed to isolate.

[0054] Further description of the isolation as effected on the conveyor belt system refers only to remote isolation station 12 but is to be understood to be equally applicable to remote isolation station 14.

[0055] The isolation procedure requires dissipation of energy which could otherwise cause safety hazards from undesirable movement of the conveyor belt 21. The conveyor belt system 20 includes a brake 21E which is activated to bring the conveyor belt 21 to a stop. At least one stored energy test is then performed to ensure that conveyor belt 21 is stationary and that all stored energy has been released. The conveyor belt movement sensor S, 900 shown in further detail in FIG. 8 and which can sense motion or travel in forward and reverse directions for the conveyor belt 21, is used to ensure that the conveyor belt 21 has come to a complete stop before isolation is effected. The speed sensor S could be provided as, or in conjunction with, a belt standstill monitor as would be known in the industry. For example, plant control system 260 may command release of conveyor brake 21E and then the conveyor belt 21 may again be monitored for movement by speed sensor S. When the conveyor belt 21 is confirmed stationary with zero speed sensed by sensor S, the brake 21E will be re-applied. The brake 21E will then be released again with the conveyor belt 21 being again monitored for movement by sensor S. This procedure may be repeated as many times as necessary until sensor S and consequently the plant control system 260 confirms that the conveyor belt 21 is completely stationary with all stored energy released or dissipated. This process may be demonstrated with reference to FIG. 5 showing a plot of brake 21E action, as reflected by brake torque, against time. Here brake 21E is applied in three pulses 21EA, of approximately equal length, with belt movement monitor S, 900 continuously monitoring movement at all times including during time intervals M between brake pulses 21EA. When no movement is sensed by belt movement monitor S, 900 after three pulses 21EA (corresponding with a certain elapsed time MA), control system 260 sends a signal to control panel 700 that the operator may proceed to isolation switch lockout as described below.

[0056] On conclusion of the above isolation procedure, remote isolation system 10 continuously monitors the integrity of conveyor belt system 20 isolation by continuous monitoring of signals received from the plurality of sensors described herein. Threats to such isolation integrity typically imply safety hazards, such as may result from conveyor belt movement, that may be pre-empted and compensated for with the equipment isolation system. As a plurality of potential threats to isolation integrity may exist, securing isolation system integrity involves the use of a combination of monitoring and securing systems for addressing the most probable threats to isolation integrity for the conveyor belt system 20. As described below, these monitoring systems include: [0057] A perimeter monitoring system including sensors 705 (as can be seen with reference to FIG. 2) for providing surveillance at a perimeter of remote isolation station 12 and alarms for providing alert signals where the perimeter is breached, or is at risk of breach, in an unauthorised manner, whatever the cause of that breach. [0058] A monitoring system for detecting any movement of the isolation lockout switch 400 and its associated key 500 from an isolated position which could result in an undesirable or hazardous re-energisation of conveyor belt system 20. [0059] A securing means involving mechanical devices, in the form of automated belt clamps integrated with remote isolation system 10 to prevent movement of the conveyor belt 21 whilst isolated. [0060] A monitoring system for detecting stored energy in the conveyor belt system 20 during isolation, suitable stored energy tests including those described above and continuous conveyor belt speed monitoring using speed sensor S. [0061] A securing means involving mechanical devices, in the form of shuttle locking pins integrated with remote isolation system 10 to prevent movement of the shuttle conveyor 25 whilst isolated. [0062] A monitoring system for detecting slackening off of the conveyor belt 21 in certain arrangements after associated counter-weights (not shown) are lowered to eliminate tension from the belt 21 and thus ensure no potential energy remains prior to and during an isolation event being effected.
The first monitoring system identifies threats of unauthorised entry to remote isolation station 12 and, in particular, its control panel 700 for which it forms an enclosure or box, i.e. (a perimeter). As shown in FIG. 2, remote isolation station 12 is mounted on post 12A and has an access door 122 enabling access to the control panel 700, this access door 122 normally being closed to unauthorised personnel to protect the control panel 700 and other safety critical components, including isolation lockout switch box 200 and lockout switch 400, from damage, typically from human interference or climatic factors. The access door 122 should not be opened, exposing these safety critical components, without authorisation. The access door 122 is therefore provided with one or more sensors 123, such as position, tamper or limit switches, to detect movement in position or status of the door 122 from a closed position, irrespective of the cause of a change in door position. The sensor 123 continuously monitors the position or status of the door 122, at least whilst conveyor belt 21 is in an isolated state. Where motion or a change of position is detected, the sensor or limit switch 123 triggers alert signals through alarms 124 and 126 fitted to the remote isolation station 12. Alarm 124 is a siren and alarm 126 is a light beacon which includes a light 126A which flashes red when triggered by the door limit switch 123. Siren 124 (which may include start up warning horns for conveyor belt system 20) may be pulsed in a preferred manner to represent the condition alarm. An alert signal is also sent to the controller 50 and central control room 40 so that corrective action can be initiated as required. Corrective action may involve tripping of a shunt trip device (not shown) at substation 30, fail-safe deactivation of the isolation system 10 and a reset of the remote isolation system 10 following an investigation to locate the cause and effects of the detected unauthorised access to remote isolation station 12. Ideally, all access doors to remote isolation stations 12, 14 are fitted with door limit switches 123 as described above.

[0063] The second monitoring system, which operates independently of the first, is described with reference to FIG. 3 showing a schematic of a control panel 700 located within the remote isolation station 12. Panel 700 has a Human Machine Interface (HMI) 710 with a touch screen 1265 (though less fragile buttons, switches and other input devices may be used in alternative arrangements) for entering commands including issuing isolation requests to the plant control system. A request button 740 is provided for isolation requests. Information can also be presented on screen 1265 in respect of any such isolation requests. Control panel 700 also includes: [0064] indicator light 720 showing whether or not the remote isolation station 12 or 14 is available for isolation; as well as whether the conveyor belt system 20 is in the desired isolation mode (as described in the Applicant's Australian Provisional Patent Application No. 2015902558; [0065] indicator light 725 showing whether or not exclusive or maintenance mode for the remote isolation system is active as described in Australian Provisional Patent Application No. 2015902557 (with the remote isolation station 12 exclusively controlling operation of the conveyor belt system 20), the contents of which are incorporated herein by way of reference; and respective select and cancel buttons for initiating or terminating the maintenance mode; [0066] indicator light 730 to provide zero energy confirmation when sensors, such as at least the voltage monitor relay described above for contacts 31, and preferably conveyor belt 21 movement sensors as well, indicate zero hazardous energy in the conveyor belt system 20; [0067] request isolation button 740 which is activated by an operator (and which illuminates when pressed) to request isolation and request approved indicator light 750 which illuminates to provide status information to said operator; [0068] indicator light block 760 for showing correctness of selection of conveyor belt 21 for isolation and for indicating that control system checking is taking place subsequent to an isolation request being instigated; [0069] indicator light block 770 for showing whether or not the isolation process is complete following control system checking; [0070] try step button 780 for requesting a try start as described above; [0071] isolation switch block 765 including switch box 200 with isolation lockout switch 400 (shown with key 500 in a normal position with keeper plate 405 locked by padlock 407 to prevent removal of key 500 from the isolation lockout switch 400). Isolation lockout is further evident with reference to FIG. 4 showing the isolation switch box 200 detached from control panel 700. Lockout switch 400 has key 500 in the isolated position with flap lock member 291 in correct position for application of hasp 600 securely and correctly accommodated for isolation lockout. Multiple operators may need to lock out and hasp 600 includes hasp lockout points 600A to enable this to occur; and [0072] graphics (in the form of arrows and text) illustrating the sequence of steps to be followed in the required isolation procedure.

[0073] Further description of the construction and operation of the lockout switch box 200 and isolation switch 400 is provided in the Applicant's Australian Provisional Patent Application No. 2015902554, the contents of which are incorporated herein by way of reference.

[0074] It is critical to safety that the isolation lock out switch 400 remains in the correct locked out position during isolation of conveyor belt 21. To that end, a second monitoring system for securing integrity of remote isolation system 10 includes sensors, such as proximity sensors to continuously monitor the position of the isolation key 500 in isolation lockout switch 400 and to ensure that various components (e.g. key 500, keeper plate 405 and flap 291) are correctly positioned in resting or NORMAL (energised), or locked out condition. Corrective action may be initiated if deviation from the correct position is indicated. Sensors can also be used to indicate tampering with hasp 600 and to initiate corrective action if tampering is detected. Alert signals may also be generated using the siren 124 and alarm 126. The signal could be different from that provided for the first monitoring system warning personnel to evacuate the working area for conveyor belt 21 if there is a significant risk of conveyor belt re-energisation, or movement, should the isolation lockout switch 400 be moved out of the correct isolated position. Corrective action may involve a reset of the remote isolation system 10 following an investigation to locate the cause and effects of deviation of the isolation lockout switch 400 from the correct lockout position.

[0075] A third monitoring system, though more aptly described a security system operating independently of the first monitoring system, provides additional security to those working on conveyor belt system 20 and conveyor belt 21, in particular, when isolated using the remote isolation system 10 as described in Australian Patent No. 2010310881 and above. This third monitoring system is described with reference to FIGS. 6 and 7. Conveyor belt 21 is provided with a number of automated belt clamps 21A for preventing belt movement during isolation. The number of belt clamps provided is typically dependent on the required holding torque required and possible mounting locations available for such clamps.

[0076] As shown in greater detail in FIG. 7, belt clamps 21A are arranged on the feed and return sides of the conveyor belt 21. Each belt clamp 21A comprises clamping plates 21AA that are brought into compressive engagement with conveyor belt 21 by a drive system 21AB including an electric motor under the control of master controller 50 of remote isolation system 10. When engaged the conveyor belt 21 should remain stationary with all energy dissipated.

[0077] Use of automated, rather than manually installed, belt clamps 21A saves time on conveyor belt maintenance and especially maintenance on the conveyor belt brake system 21E. Still further, time savings may also be achieved by integrating the engagement of belt clamps 21A with operation of the remote isolation system 10 as above described. The belt clamps 21A clamp the conveyor belt 21 by force and their engaged position may also be continuously monitored by the isolation control system. Accordingly, when isolation is approved, plant control system 260 instructs engagement of the belt clamps 21A with the conveyor belt 21 through drive system 21AB and confirms such engagement as part of the isolation procedure. Release of the belt clamps 21A by drive system 21AB is also controlled by plant control system 260. In this way, the belt clamps 21A do not require manual, or even automatic installation, in separate steps after isolation lockout has occurred which saves significant time for production. Further description of the automated belt clamp system is provided in the Applicant's Australian Provisional Patent Application No. 2015902565, the contents of which are incorporated herein by way of reference.

[0078] Use of conveyor belt clamps 21A should prevent movement of the conveyor belt 21, but conveyor belt speed or movement monitoring is also continuously conducted during isolation using speed sensor S, 900 to provide further safety assurance by checking that there is no conveyor belt 21 movement. Speed sensor S, which can also or alternatively be provided as a belt standstill monitor (BSM) 900, is shown in FIG. 8, and arranged to operate with the conveyor belt system 20. BSM 900 is ideally mounted, using mounting brackets 950, close to a belt support roller to prevent sagging of the conveyor belt 21 onto the unit. BSM 900 has a rotatable encoder roller 905 which is in contact with conveyor belt 21 and caused to rotate (either clockwise or anti-clockwise) by the movement of the belt 21. As it does so, a sensor arrangement 910, such as a Hall effect sensor, co-operates with a sensible index 908 on the encoder roller 905 allowing measurement of the rotational speed (which has a relationship with conveyor belt speed) in the manner of a conventional encoder.

[0079] The BSM 900 serves a number of key roles as are described below. Firstly, the BSM 900 is used to qualify one of the primary steps in the remote isolation process, that is, it confirms that the conveyor belt 21 is stationary. This enables a request to isolate by an operator (i.e. effected by pressing the REQUEST TO ISOLATE button 740 on the control panel 700) being recognised by the control system when received. Secondly, the BSM 900 is integral to the energy release or energy dissipation sub-routine as described hereinbefore where the conveyor brake 21E is applied and released to find the neutralised (and hence de-energised) position of the conveyor belt 21 prior to isolation. The BSM 900 facilitates continued execution cycles of the brake release routine until no movement is detected in the conveyor belt 21. Thirdly, the BSM 900 is used to continually monitor the conveyor belt 21 for movement when a remote isolation is in place and will activate alarms if movement is detected. Importantly, the BSM 900 is configured to be fit for the application purpose of a functional safety system and is designed to withstand the rigours of the installation, which involves actual contact with the conveyor belt 21 to provide direct sensing thereof.

[0080] As described above, the conveyor belt system 20 also includes a shuttle conveyor system 25 now described in more detail with reference to FIG. 9. In shuttle conveyor system 25, supported by structural members 256 and fed with iron ore from conveyor belt 21 through chute 212, a shuttle 25A at the head end of conveyor 25 moves an end or delivery tip of the conveyor back and forth, shuttling it into position over chutes 252 and 253 of a downstream conveyor (not shown). Such a shuttle conveyor may be isolated in essentially the same manner as described above and in Australian Patent No. 2010310881 using an additional remote isolation station 12A rather than less conveniently located remote isolation stations 12 and 14.

[0081] When isolated, a brake 254 for shuttle conveyor 25 is engaged and excessive reliance could be placed on that brake to hold the shuttle 25A in correct position for isolation over chute 252. This might be acceptable for minor tasks not requiring work on the shuttle 25A itself. However, as with conveyor belt clamps 21A described above, the shuttle conveyor 25 can be locked into isolation position so that shuttle 25A does not move using automated locking pins 25C driven within complementary recesses 257. The locking pins 25C are moved into position when required by electrically driven hydraulic ram 25B operated by plant control system 260 during operation of remote isolation system 10. Hydraulic ram 25B similarly retracts locking pins 25C from the locked position when shuttle conveyor 25 is ready for return to service following maintenance.

[0082] Use of automated, rather than manually installed, shuttle locking pins 25C saves time on shuttle maintenance. Still further, considerable time savings can be achieved by integrating the engagement of locking pins 25C with the remote isolation system 10 as above described. Accordingly, when isolation is approved, controller 50 instructs engagement of the locking pins 25C with the recesses 257 of shuttle conveyor 25 by hydraulic ram 25B and confirms such engagement as part of the isolation procedure. The shuttle locking pins 25C do not require manual, or even automatic, installation in separate steps after isolation lockout and this saves time for production. Further description of the shuttle locking pin system is provided in the Applicants Australian Provisional Patent Application No. 2015902566, the contents of which are incorporated herein by way of reference.

[0083] The equipment isolation system as described above provides a number of benefits. First, careful steps are taken to dissipate energy (in whatever form may cause hazard) before isolation of the conveyor belt system 20 can be effected. In this way, any potential safety hazards posed by the stored energy can be mitigated before any maintenance or other work is commenced on the isolated equipment. Second, isolation integrity during an isolation event provides even greater safety assurance by mitigating against risks of re-energisation of the conveyor belt system 20 and/or any misuse/tampering with the equipment isolation system 10. This continuous monitoring ensures the integrity of an isolation event is not compromised, as this may put anyone working on the equipment in danger of serious harm. Careful control over, and integration of, these aspects also helps minimise downtime and increases production for the overall plant or site.

[0084] In actual use, the equipment isolation system as described above typically involves transference of an equipment item from a de-isolated (or energised) state to an isolated state and then back to a de-isolated (or energised state). This is because the equipment isolation system is typically used to take the equipment item out of operation (an isolation event), in a safe and controlled manner, to enable maintenance or other work to be performed, before it is then returned back to normal operation.

[0085] Modifications and variations to the equipment isolation system of the present invention will be apparent to the skilled reader of this specification. Such modifications and variations are deemed within the scope of the present invention. For example, whilst the equipment isolation system has primarily been discussed with reference to a conveyor belt system and the dissipation of electrical and potential energy in such a system, the isolation system may have application to other types of equipment where continuous monitoring of different forms of energy, as alluded to hereinbefore, may be required.

[0086] Furthermore, while the control panel 700 has primarily been described as including a Human Machine Interface (HMI) 710 with a touch screen 1265 and a series of buttons and lights (e.g. 740, 750, 760, 770, 780 etc) to enable an operator to request an isolation event, it should be noted that the control panel 700, and specifically the touch screen 1265, may be configured to provide greater control and more information about isolation system steps to an operator (or indeed full control and all information to do with the isolation system). That is, a more digitally based input means (or indeed a totally digital system) may be arranged for operation instead of an analogue or part analogue system as described herein to enable control of the equipment isolation system according to the present invention.