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BULK HANDLING CONVEYORS

SEMINAR 12 MAY 2006

Held at the Holiday Inn, Royal Victoria, Sheffield

Organised by The Midland Institute of Mining Engineers

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Contents Welcome Message from the President of the Midland Institute of Mining Engineers

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Organising Committee 6

Sponsors of Bulk Handling Conveyors Seminar 6

Program of Events 7

Synopsis of Papers 8

Conveyor Safety

M Holyoak 16

Thermal Imaging M Deakin 22

Conveyor Performance K.Shaw, N.Battinson 32

International Perspective R Turner 42

Conveyor Overview and Innovation M Foster 51

Exhibition Stands 58

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Welcome Message

It gives me great pleasure, as President of Midland Institute of Mining Engineers; to welcome you here today to what I believe will be a rewarding investment of your time. The success of this event will depend, in part, on your interaction and subsequent contribution. Whilst each speaker will conclude with an opportunity for you raise any questions, the final session of the seminar is intended to facilitate debate on any issues raised throughout the day. There will be ample opportunity in between the sessions for you to network with other delegates and to visit the stands around the hall. I would like to thank all the organisations represented here today, in particular those attending the stands. I would recommend to everyone in attendance to take the opportunity of meeting Adele and David at the Institute of Materials Minerals and Mining (IOM3), Membership stand, where you can:

• Become a member of IOM3 • Upgrade existing membership, eg Member to Fellow • Register with the Engineering Council • Upgrade Engineering Council registration, IEng, CEng, EUR Ing

On behalf of the Midland Institute of Mining Engineers, I would like to thank all our co-sponsors and members of the organising committee for their efforts in making this event possible. In order to fulfil a meaningful review of the seminar we need to take into account the views and experiences of all in attendance, I would be most grateful if you would take a few moments of your time to complete and return the review form in the back of this booklet. Finally, thanks go to you the delegates for giving up your valuable time to join us here today. I feel sure that together we will make this event a success and that we can share our experience, exchange views and opinions, and most importantly Learn something that will make a difference in our work with bulk handling conveyors. As I said in my Presidential address: “If we do again today what we did yesterday, We’ll get the same again tomorrow” Together we have an opportunity to use today to learn how to improve tomorrow. Kevin Sabin MBA, CEng. FIMMM. President of The Midland Institute of Mining Engineers

Midland Institute of Mining Engineers, Web site- www.themime.org.uk.

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Organising Committee

Mr Kevin Sabin (Chairman) President Midland Institute of Mining Engineers

Mr Peter Scott HMI, Health & Safety Executive

Mr Malcolm Foster Continental Conveyors

Mr Peter Hetherington Head of Engineering UK Coal Mining Ltd

Mr Tim Spurry UK Coal Mining Ltd

Mr Norman E Riley Honorary Treasurer, Midland Institute of Mining Engineers

Mr Charles Rhodes Honorary Secretary, Midland Institute of Mining Engineers

Sponsors of Bulk Handling Conveyors Seminar Health & Safety Executive UK Coal Mining Ltd Continental Conveyors Midland Institute of Mining Engineers The Institute of Materials, Minerals & Mining

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Program of Events 8.30 to 9.00 Registration

9.00 to 9.05 Introduction Mr K Sabin President MIME

9.05 to 10.00 First Session Chairman Mr P Scott HMI Health & Safety Executive

Conveyor Safety Mr M Holyoak HMI Health & Safety Executive

Mr M Deakin Director, Proviso Systems

10.00 to 11.00 Second Session Chairman Mr P Hetherington Head of Engineering UK Coal

Conveyor Performance Mr K Shaw Group Engineer UK Coal

Mr N Battinson Electrical Engineer UK Coal 11.00 to 11.30 Coffee

11.30 to 12.30 Third Session Chairman Mr T Sanders Continental Conveyors Ltd

International Perspective Mr R Turner Continental Conveyors Ltd

12.30 to 2.00 Buffet Lunch Visit Exhibition Stands

2.00 to 3.00 Final Session Chairman Mr T Sanders Continental Conveyors Ltd

Conveyor overview Mr M Foster Continental Conveyors Ltd

Conveyor Innovation Mr M Foster Continental Conveyors Ltd

3.00 to 3.15 Closing Remarks Mr K Sabin President MIME

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Synopsis of Papers

Conveyor Safety MARTIN HOLYOAK BSc, CEng, MIMechE, FIMMM HM INSPECTOR OF MECHANICAL ENGINEERING IN MINES

A QUESTION OF GUARDING WHY ARE NIP GUARDS REQUIRED ON BELT CONVEYORS IN MINES BUT NOT IN

QUARRIES? The coal mining industry has a policy of guarding directly at the nip point, which evolved between 1968 and 1994 in response to fatal and severe injury accidents. It now includes all major nip points at head pulleys, tail pulleys, snub pulleys, tension pulleys and deflection pulleys. Since adopting a policy of total nip guarding such accidents have become virtually unknown in mines. British Standards used in the manufacture of belt conveyors do not apply underground in mines, because they do not automatically require the provision of nip guards and perimeter guards are traditionally used as a priority. But belt conveyor nip points are difficult to enclose because of the passage of the belt and the material. In addition, spillage may result in perimeter guards being damaged or removed and not replaced. And serious accidents continue to occur where nip guarding is not mandatory. Arguably, modern risk based European harmonised standards require more emphasis on nip guarding as a direct safeguard against a well-known and foreseeable hazard. The paper asks: Is it time to remove the mining exclusion in standards, make provision of nip guards a priority requirement in conveyor manufacture, and apply the same standards uniformly?

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Improve Safety, Maintenance and Reliability with Thermal Imaging Systems Mike Deakin – Director Proviso Systems Limited Thermal imaging systems are used extensively today throughout many industry sectors. Over

the years their application has moved from the more traditional electrical surveys and now

includes mechanical plant, temperature critical production processes, heating systems,

insulation and energy conservation.

Today’s thermal cameras have changed significantly to their predecessors.

Easier to use, smaller, lighter and more affordable, the cameras provide their user with instant,

clear thermal pictures for immediate diagnosis of potential problem areas.

With the necessary emphasis on Safety in the Workplace, used as a non-invasive inspection

tool, a thermal camera can be used remotely to examine rotating and moving equipment, even

when guarded.

This presentation provides a brief introduction into the science behind Thermal Imaging and a

guide to some of its applications on and around conveyor systems.

Used regularly as a diagnostic tool the information collected by the thermographer will

provide an invaluable contribution towards Improving Safety,

Maintenance Practices and Equipment Reliability.

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Conveyor Performance

K. Shaw. Group Engineer, UK Coal. N. Battison. Electrical Engineer UK Coal. Introduction This paper will present UK Coals views and engineering strategies on factors affecting conveyor performance in the underground coal mining application, by discussing issues and making observations on specification and design of conveyors, and our approach to engineering with particular reference to conveyors installed for plus 3000m long retracting applications. An explanation on the benefits of reliable monitoring and control will be presented and how the necessary inspection and maintenance regimes are part of our strategy to enhance performance, through reliability and operability. Specification and Design Initial concept design has to be developed from mine layout which usually dictates duty performance requirements. Calculations based on known factors and many years experience of utilising and modifying empirical data indicates conveyor design requirements. This, together with UK Coals engineering philosophy and strategy for utilising capital expenditure will be briefly explained to demonstrate our approach to using well proven technology in what can be a difficult and potentially a high risk environment. Engineering, Fit for Purpose. The paper will show details of overall conveyor design and that the selection of major components is fit for purpose, with a preference for installed power utilisation factors to ensure reserves. Our tendering process when considering new installations allows us to pull on world wide best practice and to utilise proven innovation in technology. Long Retracting Applications. To capitalise on extensive reserves in a large block of 5m thick coal, the chosen mine layout at one of UK Coals deep mines has necessitated the installation of retractable conveyors in 3000m long gate roads that can deal with, what is for UK Coal, high tonnage rates. The high costs of production in recent times has seen most deep coal mines concentrate efforts on a one face strategy and adoption of this concept demands high reliability of equipment, coupled to very little available down time for maintenance.

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Benefits of reliable Monitoring and Controlling and Drive Tripper Arrangement Philosophy. The benefits of the application and utilisation of monitoring and control technology to keep the coal on the belt, to prevent belt edge damage and spillage will be explained. The layout of a modern conveyor incorporating slip detection, belt tear and temperature protection and the way we can control the load onto the conveyor will also be demonstrated. The paper explores and discusses how these issues and their potential effects impact on performance. UK Coal has adopted technology to strive for reliability and performance by utilising soft start equipment that can give infinitely variable transmission input torques to enable more effective management of bulk handling of mineral on our plus 3000m long gate conveyors. The Paper will explain how we utilise real time control by and how auto capture of data allows for changes in operational requirements to be catered for. Inspection and Maintenance. UK Coals approach to a common conveyor maintenance strategy will be explained which is designed to be flexible to suit local conditions but is yet administered by a common approach. As in many industries our maintenance package is a mix of predictive, proactive and planned change outs. Issues of the need for maintenance will be discussed and how equipment design could be improved to reduce maintenance. Performance through Reliability An indication will be given of when performance enhancement has been achieved, especially where the utilisation of technology coupled with good standards of installation in the challenging application of plus 3000m long retractable conveyors.

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International Perspective

Mr R Turner Project Design Manager, Continental Conveyors Ltd Bulk Handling Operations around the world over the past few years have moved the goal posts with regards conveying capacities and more difficult configurations, conveyors using conventional components in non conventional applications. As an example is the advent of major tunnelling projects both in the UK and around the world belt conveyor technology has been pushed to design more complex conveyor systems using existing drive technology and develop new control methods. There is now some 100’s of Kilometres of tunnel currently being excavated today and a large majority are using belt conveyors by choice. Another example is the need to increase productivity, produce cost-effective solutions, and to provide the ability to upgrade existing installations. This presentation will give a general overview of our international experiences in several projects.

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Conveyor Overview and Inovation

Continental Conveyors Ltd. In recent years a number of key belt conveyor techniques and items of equipment have been further developed for the application of belt conveyors in the Quarries,Open Cast and Deep Mining, and Tunneling, Industries world wide, Long Overland Systems for the bulk transport of minerals are being considered more seriously now in an effort to reduce Truck Haulage Miles and improve the environment. Significant among these are: Optimised Drive Systems and Control Methods. These range from simple direct drives through to highly controllable VFD electronic systems. Direct drive is the simplest form of connecting the prime mover to the belt conveyor drive drums and is limited to small power applications,VFD controllable systems are used on very high power applications and where the installed Kw are required to be installed along the length of the conveyor system ie.as in Tripper Systems, many other methods are being used and will be covered in this presentation. High Angel Conveying. High Angle Conveyors can be classified as those conveyors which can carry minerals on inclines above which standard cannot operate. The Continental Conveyor HAC can transport almost any type of mineral at any angle up to and beyond vertical.This applies to both up hill and down hill applications. This most versatile type of High Angle Conveyor system uses only standard conveyor components and standard ply or steel cord belting, and as such, conventional drums,rollers, drives, loading sections, discharge heads, and belt cleaning devices. This type of conveyor is now being used in quarrying and open pit mining operations, and to lift mineral vertically from underground locations in the Tunneling Industry, also for storage into silo, s. Curved Conveying Curved and Curvilinear Conveyors have been successfully applied in limited applications over a number of years, in both the UK and Overseas. However in recent years the development in belt design, booster drives, soft start equipment and belt tension control systems have dramatically increased the potential for application of much tighter radii curves in conveyor systems The best way to run a conveyor is still to follow a straight line. But if the need arises then, dependent on route conditions and curve radii a conveyor can now be successfully designed to follow a curved route.

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Booster Drives/ Tripper Drives Known as Booster or Tripper Drives, Conveyors using booster technology are more generally used in the Deep Mining and Tunneling sectors but the technology can be applied to long overland conveyor systems.The booster drives are installed at strategic calculated points along the conveyor to: i) Reduce the overall belt tension in the system ii) Introduce an increase in power A booster system can be made intelligent by use of tension sensing equipment, located at each booster drive, which will trigger an increase or decrease of the tension in the system when necessary . This is achieved by automatically adjusting drum speed /torque at each booster drive. Tension is constantly monitored at each booster drive and the input power to the drive system is automatically adjusted to maintain the pre-set target tension for the particular system. Frequency Inverters. Frequency Inverters are variable speed control devices (VFD,s). They offer a number of extremely useful features to a conveyor system,particularly to long conveyors,curved conveyors,or curved and undulating systems.VFD and electronic control provide very accurate control of tension/torque when used with complex conveyor applications. Constant Tension Winches & Multi Lap Storage. Tensioning of conveyors can be achieved generally by use of three methods. Gravity Tower, Hydraulic Winch and VFD Winch, these three methods are all known as Live Tensioning systems, and provide accurate/optimum tension within the conveyor system, important particularly in terms of efficient transmission of required power to the drive drums and to constantly adjust the tensions during the changes in the system dynamics. Efficient Multi Lap Storage is vitally important particularly in Deep Mining and Tunneling applications as the majority of conveyor systems are either advancing or retreating, Continental Conveyors have made major strides in developing these systems, currently belt storage units are being used with a capacity up to 720 meters Live storage.

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A QUESTION OF GUARDING

WHY ARE NIP GUARDS REQUIRED ON BELT CONVEYORS IN MINES BUT NOT IN

QUARRIES?

BY: MARTIN HOLYOAK BSc, CEng, MIMechE, FIMMM HM INSPECTOR OF MECHANICAL ENGINEERING IN MINES INTRODUCTION. Belt conveyors continue to feature in HSE accident statistics, in particular accidents that occur because guarding is inadequate. Perhaps the most dangerous mechanical hazard on a belt conveyor is the risk of being drawn in to a nip point. Although, the term ‘nip’ is too gentle a word for what has the potential to kill or maim. There are a multitude of nip points on belt conveyors: where the belt wraps around pulleys, where there is a change of angle, and also at any place where the lifting of the belt at carrying and return idlers is restricted, or is prevented by the stiffness of the belt itself. Different standards of guarding apparently apply underground at mines to those at mine surfaces, open cast coal sites and quarries. In particular, nip guards are mandatory on belt conveyors at coal mines, but not necessarily in other industries. This paper does two things: it summarises the duties of manufacturers and users, including those who manufacture for their own use; and suggests why manufacturing standards should be applied more rigorously to provide the same protection in all industries that share the same risks. WHAT IS A NIP POINT? A nip point is defined as, the dangerous area on the in-running side at the line of contact between the conveyor belt and a rotating pulley. The nip hazard is best described by considering the old fashioned mangle. Here, two counter-rotating rollers draw material through the nip point. On a belt conveyor, one of the two rollers is replaced by the moving belt surface, but the effect is still the same: the two moving elements, the belt and the roller, will draw things into the nip point.

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Many accidents have occurred whilst cleaning spillage from around a roller or whilst scraping a roller. If the rake or shovel is drawn in to the nip point, the speed of the typical belt conveyor allows no time for conscious thought, the instinctive reaction is to grip tighter, and in less than half a second the tool, hand and arm are drawn into the nip point. The strength of the pull at a nip point should not be underestimated. Following a fatal accident where a person was drawn through the gap between a bottom idler roller and the deck plate, tests were carried out that indicated pulls of up to 25kgf could be generated for a 5 degree deflection. On high power installations, with stiff belting, little or no deflection may draw material into the nip point. And where the belt wraps around the pulley for 108degrees or more, the pull into the nip point will be considerable. The principle of nip guarding is that, if one of the moving surfaces is eliminated then the single remaining moving surface is unable to draw material in, and the hazard is eliminated. WHY DIFFERENT STANDARDS? The background to nip guarding in coal mines goes back many years. In 1968, after a number of tragic and fatal accidents at conveyor head pulleys the National Coal Board issued an instruction that every belt conveyor on the surface and underground was to be fitted with head end nip guards, and there have been no serious accidents involving head end nip points since. The instruction was later extended to include fitting nip guards to return pulleys. These mandatory requirements were included in the 1982 edition of the National Coal Board Codes and Rules - Minimum standards of fencing and guarding. In 1992, following further accidents, the fitting of nip guards to snub pulleys became mandatory. In 1994, following a fatal accident where a person was apparently drawn in to a deflection roller that was accessible by crawling under perimeter guarding, the industry required that nip guards be fitted on all belt conveyor pulleys that deflect the line of the belt other than drive pulleys in conventional mining type drive heads (i.e., not readily dismantled, fully enclosed), as shown in BS7300: 1990 figure 9, and enclosed within totally enclosing mesh guards as described in NCB Codes & Rules. A common misconception within the coal mining industry is that nip guards are an automatic requirement in manufacture – unfortunately they are not. Following privatisation of the coal industry, HM Inspectors of Mines used their influence to pursue the automatic provision of nip guards throughout the deep mining industry, including non-coal mines. The Quarries Hard Targets Initiative draws attention to the nip hazard, but the provision of nip guards has never been the automatic requirement at quarries and open cast coal sites that it has been at mines.

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THE DUTY ON THE MANUFACTURER OR SUPPLIER The Supply of Machinery Safety Regulations (as amended). SMSR apply to relevant machines (an assembly of linked parts one of which moves, or an assembly of machines) supplied for use after 1/1/95 (there was a transitional period from 1/1/93 to 1/1/95 during which SMSR was discretional), and place duties on manufacturers and suppliers. Also, where a user makes up their own equipment, or modifies existing equipment, either by combining parts from suppliers or in combination with their own made equipment, then SMSR applies to the interface of the units and to any parts they manufacture. Relevant SMSR Essential Health and Safety Requirements (EHSR) are:

• 1.3.8 - guards must be selected on the basis of the type of risk, and must be either fixed or movable (the latter relates to interlocked type guards opening and closing as part of a process, i.e. not usually relevant to conveyors);

• 1.4.1 - requires that guards are not easy to bypass or render non-operational, and enable maintenance work to be carried out by restricting access, if possible without the guard having to be dismantled.

Compliance with relevant EHSR is mandatory, so far as the state of the art allows. One way for manufacturers to show compliance with relevant EHSR is to manufacturer in accordance with harmonised standards. The European Standards Organisations (CEN and CENELEC) have produced a hierarchy of harmonised standards. Type A standards set out basic concepts for design that can be applied to all machines. Type B standards each deal with one safety aspect or device that can be used across a wide range of machines. Type C standards give detailed safety requirements for a particular machine or group of machines. (‘Harmonised’ refers to standards specifically drawn up to help manufacturers interpret EHSR and to achieve conformity with legislation on machinery safety; ‘hierarchy’ means that type C standards must comply with concepts and safety aspects in type A and B standards). The standards used in the manufacturer of a machine will be shown in the Certificate of Conformity or Certificate of Incorporation Type A standard - BSEN 292-1:1993, Safety of machinery – Basic concepts, general principles for design.

This standard requires (6.1) designers to use their experience to assess the risk and select appropriate safety measures. Factors to be taken into account when assessing a risk are (6.2), the probability of exposure to the danger zone, and the highest foreseeable severity of injury. (There is probably little difference between the conveying problems and resulting risks in mines and those in other industries, particularly at open cast coal sites and quarries).

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Type B standard - BSEN 953:1998, Safety of machinery – Guards – General requirements for the design and construction of fixed and moveable guards. This standard requires that guards should be selected from the following order of priority:

1. Local guards enclosing individual danger zones. 2. A guard enclosing all the danger zones. 3. Partial distance guards. 4. Fully surrounding distance guards.

Local guarding has the benefit that it permits access to non-hazardous zones for maintenance tasks, and is less likely to be removed. The standard defines ‘fixed guard’ as one kept in place (closed) either permanently (by welding) or by means of fasteners (nuts etc) making removal/opening impossible without using tools; and ‘enclosing guard’ as one which totally prevents access to the danger zone from all sides. A ‘fixed enclosing’ guard that can meet both these requirements should be a very effective standard of guarding. Type C standard - BSEN 620:2002, Continuous handling equipment and systems – Safety and EMC requirements for fixed belt conveyors for bulk materials. This is the base standard used for the manufacture and supply of guards on belt conveyors. (Note, BS 7300:1990, CoP for Safeguarding of the hazard points on troughed belt conveyors, is current, proposed for withdrawal, and the requirements are duplicated in BSEN 620). The standard requires ‘safeguards’ to be provided, which may take the form of fixed enclosing guards, fixed distance guards or nip guards. The following references in the standard are appropriate when considering the adequacy of guarding:

• Hazards may arise during maintenance and cleaning (4.8); • Hazards may arise if equipment can run with guards removed (4.8); • The design of guards should enable spillage to be cleared without removal of guards

(5.1.1.1 note); • If access to dangerous parts cannot be prevented by the use of fixed enclosing guards

then distance guards or nip guards shall be provided (5.1.1.4.1); • Fixed enclosing guards shall not be designed to have sufficient space to allow any

persons to enter and be enclosed inside; • Where openings are required in fixed enclosure guards, for the passage of the belt and

material, and they are greater than 120mm, then the guard at the opening shall be extended in accordance with the distance table ‘a’ in the standard.

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DUTIES PLACED ON USERS. Provision and Use of Work Equipment Regulations (as amended). PUWER 98:

• Regulation 11(1) requires employers to take effective measures to prevent access to dangerous parts.

• Regulation 11(2) provides a hierarchy of measures: the primary level of protection is fixed enclosing guards; then, to the extent these are impracticable, other guards.

• Regulation 11(3) requires that guards shall not be easily bypassed or disabled; and be constructed to allow for maintenance if possible without having to remove guards.

Guidance paragraph 214 advises the use of risk assessment to decide if measures are appropriate to the risk and consequence. The Health and Safety (Miscellaneous Amendments) Regulations 2002 made significant changes to PUWER 98. Previously, regulation 10 disapplied regulation 11 requirements covered by the EHSR. The amended regulation 10 now allows regulation 11 provisions to be applied to users:

• For work equipment not in compliance with EHSR at the time of supply/first use; • For work equipment supplied in compliance with EHSR but then altered by the user in

such a way that it no longer complies. However, care must be taken when applying regulation 11 not to require measures over and above the EHSR. WHAT IS ACCEPTABLE FOR GUARDING NIP POINTS? Cleaning out during use is a recognised conveyor problem, it can be minimised with good design, but periodically, surging of the load, belt misalignment, blockages etc, cause spillage problems. If safe isolation is conveniently close to-hand it might be viewed as a suitable safety precaution, but often this is some distance away and human nature tends to take the easier solution. To stop and clean out will interrupt the process, and production pressures can lead to poor practices. Perimeter guards are relatively easy to remove unless welded in place, and often difficult to keep in place. Removal of a single fastener, but leaving the guard essentially in place, can permit access to the danger point. Removing perimeter guards to clean out is foreseeable, as is removing them for maintenance and not replacing them. The approach by The National Coal Board/British Coal Corporation, by 1982 to provide nip guards on head and tail pulleys, and by 1994 to provide nip guards to every other belt conveyor pulley that deflects the line of the belt other than in enclosed drive heads (but including snub pulleys, and fixed and traveling pulleys in take-up devices) has been extremely successful in preventing nip point accidents over the last 10 years. Note: It should be recognized that nip guards are generally used in conjunction with some perimeter (enclosing or distance) guarding, which safeguards against contact and rotary entanglement hazards.

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The approach by the NCB/BCC, in setting its own standard as a major industry at the time, and excluding itself from national and international standards, has resulted in a traditional two-tier approach to nip guarding. Consequently, the manufacture of conveyor guarding for other than coal mines will not automatically include provision of nip guards, even on head and tail pulleys. However, the risk-based approach in modern standards arguably requires equal treatment. Unfortunately, the final bullet point in the Type C - BSEN 620 summary above is a throw back to the older prescriptive standards, and directs progress away from a risk based approach, which would lead to the provision of nip guarding, by allowing openings in fixed enclosing guards provided that the guard is extended the minimum distance in table ‘a’ of the standard. If a dangerous area can be totally enclosed in such a way that it prevents access, and there is no need for regular access, e.g. cleaning out, that would encourage an operator to remove or bypass the guard, then fixed enclosing guards are probably sufficient. The principle objective must be to prevent access to danger points, and the measures to be taken must be proportionate to the risk. Where practicable, enclosing the danger area inside a fixed guard is the preferred option, but if it is not possible to prevent access during foreseeable use, and there is a residual risk, then additional measures must be used. In such cases, it is reasonably practicable to provide nip guards on all accessible conveyor pulleys that deflect the line of the belt. (Note, there is a useful clause in BS 5667: Part19: 1980, Continuous mechanical handling equipment - belt conveyors - examples for guarding of nip points, section 4.1, which says, "it is preferable to insert devices at the danger point, since the devices protect the danger point directly....and need not be removed during maintenance work." This is a good statement). ACTIONS SUGGESTED. By Users: Health and Safety Policy documents should include requirements for nip guards on belt conveyors in line with the above principle objective statement. By Enforcers: At any site where nip guards are not provided and risk assessment shows there is a likelihood of perimeter (enclosing or distance) guards being bypassed or removed to expose a dangerous nip point, then PUWER regulation 11 may be used to enforce the requirement for nip guards in addition to perimeter guarding. By Manufacturers: Spillage and cleaning give rise to foreseeable risks, and where such is foreseeable the provision of nip guards should be an automatic requirement based on the risk approach in modern standards, unless fixed enclosing guards can totally and reliably prevent access to the nip point. Manufacturers would probably welcome such a uniform approach to the provision of nip guards.

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By Standards Makers: Provide better direction for the provision of nip guards, particularly where rough environments, remote locations, spillage, etc. give rise to additional risk of damaging, removing or bypassing perimeter type guards. Changes to British Standards may be pursued through the appropriate technical committee. To avoid the risk of conveyors being supplied from manufacturers without nip guards, and to standardise the approach to nip guarding, consideration should be given to removing the ‘mines’ exclusion from BSEN 620, the manufacturing standard for conveyor safety requirements. The views expressed in this paper are mine, not necessarily those of the Health and Safety Executive, and through this forum it is hoped to stimulate discussion and promote greater safety. Any questions, to martin.holyoak@hse.gsi.gov.uk

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Thermal Imaging

Mike Deakin – Director Proviso Systems Limited

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Conveyor Performance K.Shaw, N.Battinson

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International Perspective R Turner

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Conveyor Performance Benefits of reliable Monitoring and control K. Shaw. Group Engineer, UK Coal. N. Battison. Electrical Engineer UK Coal.

British coal introduced the document CR13 codes and rules underground belt conveyors in

1994. This document supersedes all previous documents and remains the bible for running

conveyors underground.

The document is split into 3 sections

Part 1 - Requirements for the protection of belt conveyor installations.

Part 2 – Additional requirements for man less conveyor installation.

Part 3 – Requirements for manridding by belt conveyors.

The document states “the achievable safety standards and efficient operation of conveyors are

largely dependent upon the standards of installation and maintenance of the drive conveyor,

belt cleaners and monitoring devices and the condition in which they operate. Most safety

transducers are fitted to detect abnormal operation and should not in any event be employed

to compensate for poor installation”.

CR13 dictates the minimum requirements required. We will demonstrate how these

requirements are employed and how much extra monitoring we employ to ensure conveyor

performance required is achieved.

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In essence we are about running conveyors straight carrying the correct load on them

preventing damage to all components employed “keeping the coal on the belt”

Dawmill colliery operates 13 Kilometres of conveyors to its coalface and developments all of

which are controlled on a SCADA system.

This overview shows that system. One main feature this system gives us is the ability to view

information and live data.

SCADA is capable of providing the process control that we need today and are indeed

achieving in the 21st century mining industry to remain competitive on the world stage.

The Colour Displays is the single thing that brings together the 2 key elements of any

business, the man and machinery he is working with. The innovation within our industry can

only be seen realised and understood by the use of easily understood clear and concise Colour

Mimics on site at all plant and Process.

All the mimics that you see in the following slides are duplicated both on site for the man and

remotely on the surface, or via remote log in access any were in the world. They are in exactly

the same format so that help, advice and analysis of the process can take place either on the

mine site or indeed any were throughout the world.

Colour displays can be used to view running information or for fault diagnostics, as in the

case being shown that of SID 3 conveyors start and stop sequences.

It is simple even for me to follow the sequence through. The flow diagram changes to green

as the start is initiated so that at any point if a failure occurs both operators and craftsmen

alike are directed to the area of the potential problem.

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The conveyor Infrastructure is now fully monitored so that all information on each element

installed can be viewed at any time by operators craftsmen and supervisors alike at any place.

Benefits of reliable Monitoring and control

Belt slip protection.

CR13 states to prevent danger arising due to belt slip, a slip detector device shall be fitted

which stops the conveyor if belt slip exceeds 25% of the theoretical full driving speed of the

conveyor. In most instances today we fit 2 as in the case shown 31s number 1 conveyor.

Should one unit fail we instantly go onto the other unit without the plant being controlled

stopped. In most instances the form of slip is that of true slip, were we compare a driven drum

to a non driven drum.

Blocked chute.

CR13 states Blocked chute device(s) shall be fitted to the points of all transfer points at all

positions when spillage could give rise to danger. These are fitted at the main drive delivery

and at the tripper delivery. In addition to these we fit back spillage devices at the back of each

delivery. Operational experience as shown that on occasions, with the right combination of

mineral the delivery gets blocked behind the chute causing major spillage. These back spill

devices trip the conveyor should this happen.

Belt Alignment.

CR 13 states a belt alignment device shall be fitted, normally on the top belt as it arrives at the

drive head. In the case show 31s number 1 conveyor again you can clearly see that we fit

considerably more devices than that. This is a retracting conveyor and as stated running

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conveyors straight is essential for high performance so on this conveyor 10 devices are fitted

through out its length.

Main delivery jib

Main drive

Main drive loop

Tripper jib

Tail end

Each device is located no more than 75mm from the belt edge.

Belt tear.

CR13 states a belt tear device shall be fitted at a safe run down distance from the loading

point. Again we fit considerably more.All our belt tear devices are dual tear alignment

devices.

Smoke/ Fire detection

CR13 states a smoke or fire detector shall be fitted, which should be arranged to produce a

high priority alarm at the manned control point. The only transducers employed at Dawmill

today are of the analogue type and are continually data logged so that trend graphs can be

obtained and are used to trip the conveyor at a set level of CO. the devices are sited on the

down wind side of the conveyor and loop arrangement.

Temperature monitoring

CR13 in part 1 is very prescriptive regarding thermal devices for scoops ATLC controlled

fluid couplings brakes and anti run back devices, all of which are used less and less with the

introduction of variable speed drive technology. The fitting of general temperature monitoring

is covered in part 2. Temperature monitors should be fitted where ever there is a danger that

the rise in temperature can initiate the ignition of coal dust or cause major mechanical

damage. The setting of each device should be set to 10 degrees C above the normal running

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temperature and the operation of a device shall give local indication and shall provide a

warning at the manned control point. At Dawmill there is not a driven or non driven roller that

is not monitored by an insertion analogue device.

We exceed the company standard at Dawmill. The company standard is if any temperature

rise 10 degrees above normal running temperature is detected the conveyor is tripped within

30 minutes and if that temperature then rises another 10 degrees in that time then the

conveyor is tripped instantly. At Dawmill we give an alarm at 5 degrees above normal

running temperature and trip instantly at 10 degrees above normal running.

I refer back to what CR13 which states, Most safety transducers are fitted to detect abnormal

operation and should not in any event be employed to compensate for poor installation”. The

fitting of transducers and the policy we employ at Dawmill on tripping each conveyor at a 10

degrees rise in temperature ensure high standards. No person employed at Dawmill is

prepared to except conveyors tripping down to over temperature misalignments or any thing

else, this ensures that standards are high and maintained. Whilst I am engineer at Dawmill the

fitting of reliable monitoring to run conveyors efficiently will not be compromised.

In addition to what’s called for in CR13 the following are also monitored and if required used

to trip conveyors for operational efficiency (to describe)

Vibration

Online loop tension

All Breuer motor information and water flows/temperature for tripping.

In all instances of a device tripping the conveyor CR13 states that the trip shall be indicated at

the manned point, the colliery control room. With the use of the colour displays we not only

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do this we also indicate locally on site. Operators and craftsmen alike can view what the trip

is and see in simple easily understood format what and were the trip is. Gentleman even I can

understand today.

Automatic Speed control of the face cutting machine.

Automatic Speed control of the face cutting machine, as stated one of the main criteria for

running conveyors at peak performances is not overloading them with mineral.

Extracting 5 meters of coal at Dawmill brings its own unique set of problems. With a coal

face that is capable of producing and clearing up to 4000TPH and a gate conveyor that can

carry only 2000 TPH the size of that problem can be seen.

The Eickhoff machine employees its own internal speed control system. This is used through

out the face to limit the maximum cut speed. It allows flit speeds at either end of the face of

up to 23m/min when not in full cut.

The problem at Dawmill however is not just about cut coal, it is also about the coal that spalls

falling onto the AFC, at 5 meters extraction this at times can be in extremely large amounts.

This mimic shows the machine cutting normally, its speed being limited by the internal

Eickhoff speed control. Note the Z graph in the bottom left hand corner, this shows the cutting

for the shift. This is the best performance 31s as done on any day shift, 3.5 cuts about 7000

tons of coal.

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The system we have employed to limit the speed of the machine under these circumstances is

to continually average the current of the 4 Breuer motors employed on the gate conveyor.

These are at the bottom in the middle of this mimic showing 88, 75, 69 and 69 amps.

Knowing the current required to deliver 2000TPH allows us to average the 4 currents out

automatically. Having done this we send a signal to the face in the fibre cable from the

conveyor PLC to the Face PLC slowing the machine cut speed down proportionately

maintaining a constant 2000TPH.the machine mimic at this stage will indicate Speed control

initiated in the top right hand corner. The range of this signal is infinitely variable and easily

changeable through out its range .

The latest set of software installed in the machine automatically allows the speed of the

machine to increase when either an internal or external speed restriction is removed allowing

full set speed to be automatically attained again.

Indeed the biggest challenge we face today at DawMill is finding and utilising the optimum

cutting speed for the coal face preventing overloading of the conveyor system. The system we

now have employed allows us to fine tune the out feed to maximise conveyor run time.

Breuer Motor Main Drive and Driven Tripper Control.

The Breuer motor since its introduction as attracted in some instances bad press, however

since it successful use in the driven tripper application it as proved to be a major success and

step forward in the fully integrated face control process. The frequency inverter gives full

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speed control across its range from zero to full speed with full torque control. The advantages

this gives us at DawMill are.

• Lower Belt tensions

• Belt is easier to handle in gate belt applications

• Total control of start-up torque

• Minimal belt stretch on start-up

• Modular drive units that are easy to dismantle and transport

• Potential for matching gate belt speed to face performance

• Slow speed facility available for belt change and joint examination

This overview shows the amount of tension required if a single head drive configuration had

been employed on 31s with a 3000 meter conveyor. A single head drive would require 560

Killo newtons of tension requiring type 18 belt as thick as my arm. The logistics of handling

this style of belt in these quantities is not practical.

By installing 2 Main drive and driven tripper units you can see we reduce the tension required

down to 120Killo newtons, allowing us to use type 10 rubber which is far easier to handle.

Tripper booster drives are inserted at strategic points along a conveyor to introduce drive

power. Control is achieved by monitoring belt tensions using a tension sensor mounted behind

the tripper return drum. In theory as long as the control scheme employed is capable there is

no limit on the length of the conveyor.

Breuer VSD interface 31s coal gate conveyor

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The conveyor is controlled by the main supervisory PLC containing the control algorithm.

This communicates to the drive PLCs at each drive site on fibre optic cable.

The main drive Breuer motors ramp up on a fixed acceleration ramp from 0 to full speed.

The tripper drive motors accelerate on the load cell inputs at the tripper site.

An increase in load cell tonnage increases the speed of the motors, a decrease in load cell

tonnage slows the motors down.

This has the effect of providing the desired kilowatts required at the tripper site to working

with the head drive at constant speed.

Using Ethernet IP communications as reduced the motor response time from 600 milli

seconds on the first application tried on 301s were the control was rather lumpy so to speak

down to 50 milliseconds in this application were the control is excellent. This is proven by the

constant tonnage in the loop system.

Torque control through out the full range on this application is achieved by limiting the

current each motor can take in essence always denying it of the full current it desires to drive

its load.

(Also to be described the reduced speed running of Variable speed drive conveyors for

operational efficiency.)

SCADA and Predictive Tending. SCADA also gives us Predictive Trending Facilities. This allows us to trend any of the 12500

tags on the server in any format we require. This is a massive untapped tool. A tag is any

piece of information we send to surface such as blocked chutes or temperature monitoring.

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The ones being displayed as examples are those of weigher TPH on 31s gate conveyor the red

a blue cursors can be moved anywhere on the graph displaying the value at that point. On this

graph they show 1087 TPH and 1242 TPH.

This graph shows the average Breuer current over the same time period.

Overlay the 2 on the same graph and we compare tons per hour produced against the average

current on the conveyor. This is a graph that is run daily to enable us to set the current feed

back limit to the face machine effectively controlling the load on the conveyor system.

This is however just one example. If you think that every driven and non driven roller at

Dawmill on the conveyor line is temperature monitored we are increasingly producing graphs

and reports by exception on any rising trends predicting early failures. This allows us to

change components out prior to failure maximizing run time.

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International Perspective Mr R Turner Project Design Manager, Continental Conveyors Ltd Bulk Handling Operations around the world over the past few years have moved the goal posts with regards conveying capacities and more difficult configurations, conveyors using conventional components in non conventional applications. As an example is the advent of major tunnelling projects both in the UK and around the world belt conveyor technology has been pushed to design more complex conveyor systems using existing drive technology and develop new control methods. There is now some 100’s of Kilometres of tunnel currently being excavated today and a large majority are using belt conveyors by choice. Another example is the need to increase productivity, produce cost-effective solutions, and to provide the ability to upgrade existing installations. This presentation will give a general overview of our international experiences in several projects. Tunnelling

Barcelona Metro Currently today the underground metro is being extended by the addition of line 9, this is some 14kM of 10.9m diameter tunnel being excavated beneath the city of Barcelona. Phase I, which is now completed is a 4.7kM tunnel with a very complex shape, with the use of booster drives the excavation was achieved with a single conveyor handling very abrasive and variable material composition. Material Excavation!

Barcelona Line 9 map Phase I With Phase I now complete the next two phases are set to commence later this year using new and the original equipment from Phase I along with a further contract to extend the metro to the international Airport.

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Karahnjukar Dam Iceland Currently today in a remote part of Iceland in excess of 30kM of tunnel is being excavated in the construction of a major hydro electric plant designed to harness the power of some of east Iceland’s great glacial rivers.

Projected Dam

Overview Map Of the 3 Adit’s being driven Adit 1 is the most advanced at 13kM. The material is being transported on a single belt conveyor using booster drives. Currently installed is a 2 x 160kW Head drive, 4 off 160kW top belt boosters and a single 160kW bottom belt booster with a final fifth top belt booster yet to be installed to complete the 16kM flight.

Adit 1

Towards Karahjukar

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Underground Coal

United States Coal production in the US has never been so intense, with mines pressing for higher productivity and conveyor availability. Tripper Booster drives have been used for many years in the US mines but today some of the biggest units are being employed. One example at Twenty-mile mine in Colorado is a 2 x 1000kW Head unit with 3 single 1000kW boosters one of which is actually providing braking effort for the system rather than motive power (a similar project is currently being considered in the UK). Open type drives are used extensively underground and auxiliary equipment such as belt handling and transportation are important factors in productivity.

Open type drives for both gate and trunk conveyors are commonly used with skid mounted frames to aid transportation, this type drive evolved due to US roadways are generally inseam multi-entry systems where width is available and height it restricted. The use of rubber lagging is also common. Belt reeling stations with hydraulic ranging arms andthe ability to swivel 90 to facilitate installation andextraction.

e

tao

CEMA standard Idler construction in the US employs taper roller bearings and conveyor structure is not totally cost driven.

Vector Flux winch systems ardevelopment particularly for mcapacity conveyors, the advanbeing that FLP equipment is nrequired. The hydraulic winch system is still popular with some operators.

a recent edium to high ge in the US t generally

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Tensioning unit belt separators are an important feature of large capacity multiple lap loop systems. Now introduced successfully in the UK

Modular Slider Bed units are common on high production conveyor loading sections.

Bunkers are Back An export from the UK Coal industry in 1985 was moving bed bunkers, today in two US mines 900t dirt and 600t coal moving bed bunkers have been installed. At Twenty-mile coal mine (Colorado) a 900t dirt bunker with 5000TPH input and output rates was installed and commissioned in late 2004. The bunker is used to store mined material from the development faces whilst normal production from the main longwall coal face is transported out of the mine on the trunk conveyor system. This bunker is controlled from the surface and by use of belt weighing equipment and changeover chutes the material from the bunker is discharged onto the conveyor system when space on the belt is seen.

Bunker Discharge

Belt Space Monitoring Screen At SUFCO mine in UTHA the second of the 2 units a 600t coal bunker with 4000TPH input and 3500TPH output was installed and commissioned in early 2006. The bunker is used in the longwall coal face stream to reduce excessive capacities reaching the trunk conveyors

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transporting coal to the surface. Both these units use multi-chain technology developed originally during the channel tunnel project and include hydraulic tensioning and direct drive.

Underground Coal

Australia

The underground coal scene in Australia is currently much similar to the US where the use of open type drives is common and vector flux winch systems are being operated.

Dendrobium Mine Project (2003-2004) Illawarra Region, New South Wales This project included a Regenerative Trunk / Stockpile Conveyor with a capacity of 6000 t/h, 1800mm BW with an installed power of 1 x 450 kW TPKL drive and3 x wet disc brake systems.

Two Maingate Conveyors with a capacity of 4500 t/h, 1500mm BW with an installed power of 3 x 375 kW TPKL drives. KM Trunk Conveyor with a capacity of 6000 t/h, 1800mm BW with an installed power of 2 x 375 kW TPKL drives. NM Trunk Conveyor-6000 t/h, 1800mm BW with an installed power of 3 x 450 kW TPKL drives.

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China - Tianjin port facility Equipment supplied from our Australian operation was used in the construction of Tianjin port facility a 9kM overland conveyor with 4 x 1750kW VFD drives installed with environmental temperatures of –20 to +40 C.

Technical challenges included 2 horizontal curves with 1 of the curves incorporating a bridge crossing over a river with convex and concave vertical curve sections.

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Development of Control techniques If we focus on the Barcelona Metro project one of the conditions faced with the drive units which was not foreseen at the design stage, was periods of time when individual boosters were being towed into a regenerative condition. Although this problem was not a serious mechanical problem as the tunnel extended and became more complex the stoppages due to the Variable Frequency Drives internal protection being trigger due to regeneration were far too regular and were interfering with production of the tunnel. To try to solve this problem we obtained large amounts of running data including real time load cell and power readings some examples of these are included. Two solutions were pursued. Variable Tension control and Catch on the Fly. Variable Tension Control: With a complex booster system such as Bacelona where the position of the boosters in the conveyor are dictated by tunnel topography plus the variable material loading conditions it is inevitable that one or more of the boosters could be towed into regeneration. Using the data captured we were able to reproduce in calculation the conditions on site and show that between the conveyor being empty and full the ideal target tension was significantly different. To resolve this a software routine was created to monitor the power of each booster and alter the target tension requirement dynamically.

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Captured Data Example Power of Boosters over Time

Target setting trend

Catch on the Fly: This technique is used by Variable Frequency Drive integrators to allow the drive to free wheel when it is not required to drive, thus it automatically ignores the regeneration condition as it is towed. Variable tension control and Catch on the fly will further enhance optimising drive configurations for complex conveyors.

Calculation techniques Globally Continental use a common analysis programs which are regularly reviewed to ensure consistency and updating of any idler or belt data, this also allows easy dialog between operations ensuring experience is shared. Examples or analysis output

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To conclude this short paper, reference the international perspective of the bulk handling scene. Conveyor system output requirements are increasingly greater and configurations more complex. This requires the use of more sophisticated drives and controls systems, this conveyor technology is now available to us enabling the design and manufacture of conveyor systems equal to these tasks.

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Conveyor Overview and Innovations

Mr Malcolm Foster Consultant

Unique Applications of Troughed Belt Conveyors In recent years a number of key belt conveyor techniques and items of equipment have been further developed for the application of belt conveyors in the Quarries, Mining and Tunnelling Industries. This paper will discuss these techniques and items of equipment, and some case studies where they are applied to standard troughed belt equipment in unique projects. Significant among these are: High Angle Conveying Curved Conveying Booster Drives Frequency Inverters Constant Tension Winches & Multi-Lap Storage Systems High Angle Conveyors High Angle Conveyors can be classified as those conveyors which can carry materials on inclines above which standard conveyors can no longer operate. The Continental Conveyor HAC can transport almost any type of material at any angle up to and beyond vertical. This applies to both uphill and downhill applications. This most versatile type of High Angle Conveyor system uses only standard conveyor components and standard ply or steel cord belting, and as such, conventional drums, rollers, drives, loading sections, discharge heads and belt cleaning devices are used. This type of conveyor is now being used in quarrying and open pit mining operations, and to lift materials vertically from underground locations and to the top of storage silo’s

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The method of containment allows this system to move materials as diverse as grain to mined ore Current systems are operating at capacities from 15 t/hr to 2000 t/hr, with installed powers from 5 to 2000kw at angles of –35 to +90 degrees and lifts of +180m. And as belt strengths are increasing so is the potential for ever increasing tonnage’s to be lifted over ever increasing heights. Benefits include: • A small footprint required to install and elevate the material. This free’s up expensive

land which would normally be taken up by a long inclined conveyor, or where land / space is limited.

• Modular construction, typically takes only one week to install a 25m vertical system. • Uses only standard conveyor belts and components. The most recent vertical lifts in the UK have taken place here in London on the Heathrow Terminal 5 Tunnelling Projects. Two HAC’s were used on phases of this project. They were of modular design to facilitate frequent moves between vertical shafts as tunnelling progressed. Each was capable of lifting 600 tonnes/hour of London Clay at an average vertical lift of 30m. Case Study Slides: System Spec. / HAC in Shaft / HAC Discharge on surface Curved Conveying Curved and curvilinear conveyors have been successfully applied in limited applications over a number of years, both in the UK and overseas. However, in recent years the developments in belt design, booster drives, soft start equipment and belt tension control systems have dramatically increased the potential for application of much tighter radii curves in conveyor systems. The best way to run a conveyor is still to follow a straight line. But if the need arises, then, dependent on the route conditions and curve radii a conveyor can now be successfully designed to follow a curved route. Much of the recent experience associated with successful applications of curved conveyor technology has been gained, often of necessity, in the underground civil tunnelling sector where curves in conveyors have become the norm rather than a unique requirement.

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This experience can now be applied to the mining and quarrying sectors as shown in these pictures. r

TunnellingTunnelling

Wienerberger CurveWienerberger Curve

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. However, tunnelling applications are still the most challenging, Barcelona Metro Line 9 project which is probably the most difficult curved conveyor project undertaken to date anywhere in the world.

• • •• • • BARCELONA METRO LINEA 9 BARCELONA METRO LINEA 9

Minimum Radius280m

Phase I - Finish

Phase I - TBMLaunch

2 x 160kW Head Drive5 x 160kW Booster Units

Booster Drives Conveyors using booster technology are more generally used in the Mining & Tunnelling sectors but the technology can be applied to long overland conveyor systems. The booster drives are installed at strategic calculated points along the conveyor to; i) Reduce the overall tension in the system. ii) Introduce an increase in power A booster drive system can be made intelligent by the use of tension sensing equipment, located at each booster unit, which will trigger an increase or decrease of tension in the system when necessary. This is achieved by automatically adjusting drum speed/torque at each booster drive. Tension is constantly monitored at each booster and the input power to the drive system is automatically adjusted to maintain the pre-set target tension for the particular system.

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• • • BOOSTER TECHNOLOGY

Booster System

Single Head Drive

Conveyor LengthTe

nsi

onTe

nsi

on

Starting Tension

StartingTension

Application is particularly relevant to conveyor routes having curves or a combination of curves and undulations. The positioning of the booster drives allows for lowering of belt tensions at critical points along the conveyor where the curves and undulations have to be negotiated. The capability of booster drives to lower belt tensions means that lower strength belts can be used with the benefits of lower cost belting and associated conveyor structures and components. Frequency Inverters Frequency Inverters are variable speed control devices (VFD’s). They offer a number of extremely useful features to a conveyor system, particularly to long conveyors, curved conveyors, or curved and undulating systems. Benefits include: • Infinitely variable speed facilities. • Controlled start-up ramps which can significantly reduce system starting stresses. • Can run indefinitely at slower speeds which can be matched to production variations. For

instance it should be possible for a belt weigher to control belt speed related to load. • In freezing conditions it is possible to run at slow continuous speed during

night-time non-production times to prevent seizure of components due to ice formation. • Precise torque limiting facility which can offer greater protection against unforeseen

overload conditions and dynamic stall situations. • In the case of driven trippers the use of Variable Frequency Drives (VFD’s) and PLC

combinations are essential to control the Power and Tension applied.

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Constant Tension Winches

Tensioning of the conveyor system can be achieved generally by use of three methods. Gravity Tower, Hydraulic Winch and Variable Frequency Drive Winch. Gravity Towers are universally known and most suitable where there are no constraints of height and the conveyor is of a fixed length. However, where height is not available and the conveyor length is continuously changing there are now other means of maintaining the correct belt tensions.

Hydraulic Type This was the first system for application of constant tension to a conveyor belt and was developed by Continental Conveyor. Tension is applied to the belt by the use of a hydraulic motor driving the rope winch system. The hydraulic winch is ‘live’ at all times during the running of the conveyor. The hydraulic winch is driven by an infinitely variable, volume/pressure compensated pump. Tension is converted into hydraulic pressure via the rope winch system, the pump is pre-set to maintain a fixed pressure which ensures a constant tension during all conveyor running conditions. Optimum running tensions are vitally important to prevent belt slip and to get maximum life from all the rotary components. The unit is fitted with a brake to ensure system tension is maintained during power failure or emergency shutdown.

Variable Frequency Drive (VFD) Type A combination of VFD and gearbox can be used in a winch configuration to provide a constant tension to the belt at all times by means of a rope system attached to the moving carriage in the loop tensioning arrangement. This can also provide the ability to apply different tensions for different loading and operational conditions, and is fitted with a brake to ensure tension is maintained during a power failure or emergency shutdown situation. Benefits of Constant Tension Winch Systems: • Significantly contribute to life and reliability of the system • Automatically adjusts tensions for start-up, running and stopping. • Eliminates the need for weights and towers where space and height are not readily

available. • Safer and easier belt maintenance Currently a new type of constant tension winch drive/control is being used by Continental Conveyor in the USA (Now around 20 installations). This is a Vectored Flux Drive system which provides full torque & full braking capability in both directions.

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Case Studies Recent projects, which successfully utilised combinations of the equipment and techniques discussed, are Heathrow Terminal 5 and the Barcelona Metro Project: Heathrow: This project has combined; High Angle Conveying 35m vertical lift Opposing Curved Conveying 2 x 320m radius Constant Tension Winch Hydraulic type Multiple-lap storage system 320m ‘live’ belt storage Barcelona Metro: This project has combined: Curved Conveying: 5 x curves of 280m to 320m radius. Booster/Trippers 5 off 160kW boosters Variable Frequency Drives VFD controlled Constant Tension Winch Hydraulic type Multiple lap storage loops 720m ‘live’ storage facility In conclusion, it is now possible using conventional conveyor components to transport material round curves, up or down steep inclines and over longer distances in more difficult terrain than was thought possible only a few years ago.

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List of Exhibition Stands

ABMEC

Allenwest Wallacetown

ATB Morley

Breuer Motoren

Cen-Tech

Continental Conveyors

Davis Derby

Hagglunds Drives

Horizon Drives

IOM3 Membership

Proviso Systems

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Notes

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Notes

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Notes

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Notes