best practices in bearing reliability - ciwg minutes.pdf

SIRF Industrial Maintenance Roundtable - S.E. Area of 23 Terry Blackman

Common Interest Work Group Best Practices in Bearing Reliability and Maintenance

SIRF Industrial Maintenance

Roundtables – S.E. Area

Rt

Best

Practices in Lubrication

AVAILABLITY

MAINTAIN

IMPROVE

INSTALL

Training, & Installation

Procedures

Stocking

Conditions &

Supplier Agreements

RCA &

Reliability Improvements

October 12

November 30

February 8

April 5


Contents

1. INTRODUCTION: ............................................................................................................................................................... 3 2. MEETING #1 – SCOPE MEETING ................................................................................................................................. 4 3. MEETING # 2 – TRAINING AND INSTALLATION................................................................................................... 5

3.1 TRAINING ....................................................................................................................................................................... 5 3.2 INSTALLATION: .............................................................................................................................................................. 5

3.2.1 Cleanliness – a clean installation environment is important................................................................................ 5 3.2.2 Pre-Installation checks ............................................................................................................................................ 5 3.2.3 Mounting Procedure – Critical for Bearings with Tapered Bore (K). ................................................................. 6 3.2.4 Mounting Tools – Use the Right Tools ................................................................................................................... 6 3.2.5 To work out what tools are required: ..................................................................................................................... 6 3.2.6 Dismounting Procedures:........................................................................................................................................ 6

3.3 REPLACING SEALED BEARINGS: ................................................................................................................................... 7 4. MEETING #3 - BEST PRACTICES IN BEARING LUBRICATION ........................................................................ 8

4.1 PERSONNEL: ................................................................................................................................................................... 8 4.2 STORAGE AND HANDLING: ............................................................................................................................................ 8 4.3 SAFETY:.......................................................................................................................................................................... 9 4.4 TRAINING: .................................................................................................................................................................... 10 4.5 FLUSHING OF GEARBOXES: ......................................................................................................................................... 10 4.6 LABELLING:.................................................................................................................................................................. 10 4.7 RELUBRICATION QUANTITIES: .................................................................................................................................... 10 4.8 RATIONALISATION: ...................................................................................................................................................... 11 4.9 AUTOMATIC LUBRICATORS:........................................................................................................................................ 11 4.10 SOFTWARE AND SCHEDULING:.................................................................................................................................... 11 4.11 MAGNETS, BREATHERS AND PURGE HOLES:.............................................................................................................. 11

5. MEETING # 4 - ROOT CAUSE FAILURE ANALYSIS & RELIABILITY IMPROVEMENTS ....................... 13 5.1 SUMMARY OF COMPANIES RCA PROCESSES AND IMPROVEMENT METHODOLOGIES ............................................... 13

5.1.1 Best Practices in Bearing Reliability Improvement............................................................................................. 14 5.1.2 Specific Bearing Failurr Information ................................................................................................................... 14

5.2 CASE STUDIES OF IMPROVEMENT PROJECTS .............................................................................................................. 15 5.2.1 Bluescope Steel....................................................................................................................................................... 15 5.2.2 TRUenergy Yallourn – Pulley Housing Redesign................................................................................................ 16

5.3 SUPPLIER TECHNICAL SUPPORT .................................................................................................................................. 16 5.4. TECHNOLOGIES THAT CAN IMPROVE RELIABILITY ..................................................................................................... 17

5.4.1 Two-Bearing Units for Fans.................................................................................................................................. 17 5.4.2 ConCentra (Pop-Release) Bearing Units. ............................................................................................................ 18 5.4.3 CARB Toroidal Bearings....................................................................................................................................... 19

5.5 COST-BENEFIT ANALYSIS ............................................................................................................................................ 20 APPENDIX 1 - MEETING DATES & LOCATIONS ............................................................................................................ 21 APPENDIX 2 - ATTENDEES LIST.......................................................................................................................................... 22 APPENDIX 3 - REFERENCE MATERIAL............................................................................................................................ 23


1. Introduction: Bearings are at the heart of rotating equipment and their reliability is often critical to the operation of plant and equipment. The purchase cost of bearings is proportionally very small compared to the maintenance cost of replacement and potential lost production caused by failure. The purpose of this Common Interest Work Group (CIWG) is to discuss the various factors affecting bearing performance and share practices that members have successfully implemented to overcome known problems. There will be four CIWG meetings covering the areas of interest to the members. CIWGs will be held on member sites to allow for a short overview of the host company’s initiatives in a particular area relevant to the topic.


2. Meeting #1 – Scope Meeting Location: Qenos- Altona Host: Gavin Clark The areas of interest expressed by members can be broadly classified into four (4) areas:

1. Lubrication 2. Training and Installation 3. Root Cause Failure Analysis & Improvements 4. Stock & Suppliers

Main Topic(s) Sub-topics

Training & Installation

What’s available out there, Procedure documentation, use of check lists & job packs, using the right tools & equipment, getting the basics right, preventing skidding under light loads, subcontractor skills. Specs. for off-site repairers, specs. for new equipment, specs for turnkey projects, particularly for fans, motors & Plummer blocks. Using “greased for life” applications, cages

Lubrication

Who should do it?, labelling of containers, stopping cross-contamination , setting up routines, using magnets in oil, software available, lubrication intervals based on hours, cleaning sumps for sludge removal?, grease fill in Plummer blocks, storage of oil, oil rationalisation, using subcontractors for lubrication, filtration standards, oil mist applications, bearing isolators, use of auto-lubricators, breathers, sealing types for housings, purge points.

RCA & Reliability Improvements

Bearing Failures analysis (RCA, Post mortems), improvement examples, involving operators, monitoring and predicting failures in slow speed bearings, Alternatives and technology upgrades,

Stock, Suppliers & Stores

Shelf life, vibration isolation, critical spares management, stock rotation practices, checking condition of old stock, refurbishment of bearings. What’s in the contracts?, Technical support, web sites, KPI’s, Maintenance Involvement in decisions.


3. Meeting # 2 – Training and Installation Location: Bluescope Steel – Hastings Host: Rod Bennett Bearing failures due to incorrect installation are reported to account for between 16% and 36% of all premature bearing failures. The root cause of the incorrect installation in most cases is lack of specific bearing installation training, incorrect use of tools, use of the wrong tools, contamination during fitting and incorrect tolerances of shafts and housings. These can all be avoided and the path to best practices in bearing reliability and maintenance starts with addressing these issues:

3.1 Training

• Utilise vendors where possible for short training courses on site e.g. Blusecope Steel get CBC to do regular 3 hour training courses on site. Other vendors will do the same if asked. Check to see what free training is available with supply contracts.

• Make training also available for contractors to ensure they get upskilled as well. • Include Engineers, Supervisors & Planners in Training courses as it cannot be assumed that

they understand the need for getting the basics right. • It’s particularly important that Supervisors are knowledgeable about bearing installation so they

can supervise contractors who may not be trained in this area. • Accredited 3-day courses are also available - see SKF “Course in Bearing Technology &

Maintenance”. These cover all aspects of bearing maintenance. • Include examples of the costs of failures in training to emphasise the importance of correct

installation.

3.2 Installation:

3.2.1 Cleanliness – a clean installation environment is important

• Ensure the workshop area where bearings are fitted is clean • When installation is in the open, create a wind break and cover the bearing to prevent

contamination. • Don’t unpack or unwrap until ready to install to reduce risk of contamination. • Wash out contaminants if the dust has blown on the bearing.

3.2.2 Pre-Installation checks • Find out what the tolerances should be from manufacturer’s drawings or bearing catalogues. • Check shaft and housing tolerances for wear and conformity. This is a critical step that is often

not done. Shafts and housings must be checked dimensionally in 3 positions in 3 planes. • Use a Straight-edge and bearing blue when checking and repair if there is not a minimum of

80% contact.


3.2.3 Mounting Procedure – Critical for Bearings with Tapered Bore (K). • Have mounting instructions for Self Aligning Double-Row Ball and Roller Bearings supplied

with the bearing. e.g. Bluescope example where the vendor supplies instructions attached to each bearing box.

• Supply mounting detail checklist with the bearing to record actual mounting clearances. • Download mounting instructions from websites. e.g. www.skf.com/mount • These issues increase in importance when contractors and casuals are doing the installation and

their skill in this area in not known. • Document worksheets for critical jobs and include the instructions in the CMMS. • Record installed clearance dimensions of large bearings to enable calculation of wear by

measurements taken at some future date. • For infrequent and critical installations, contact your bearing supplier to provide an engineer for

on-site supervision.

3.2.4 Mounting Tools – Use the Right Tools • Bearing Magnetic Induction heaters will do 80% of all tight inner-ring fit bearings. • Ensure the heaters have a working temperature probe and check its accuracy with a contact

Thermometer. Get training on the use of the heater from the supplier. • Use an Impact mounting kit for small bearings (up to 50mm bore) instead of pipes and home-

made dollies. • Use correct “C” (hook) or impact spanners for lock nuts for adapter sleeves. • Use Hydraulic Nuts for bearings on adapter sleeves and tapered journals over 100mm where

possible. • Dial indicators can be useful for measuring drive-up distances and can be fitted to the newer

hydraulic nuts. Use hydraulic pumps with calibrated gauges for connecting to hydraulic nuts not standard Enerpac type pumps.

• Ensure fitters have a good set of Feeler Gauges for checking clearance when mounting tapered bore bearings. Feeler gauges can be made a stores stock code so that they are re-ordered automatically.

3.2.5 To work out what tools are required: • Get a list of bearings from the store (and their usage) and sort by part number and criticality. • Bearings with the suffix “K” (Tapered bore) will generally need fitting with hook spanners or

hydraulic nuts. Check the bearing supplier’s manuals or the www.skf.com/mount web site for the right tools for the bearings.

• Order the tools that are not already in the tool store so they are available for the next installation.

3.2.6 Dismounting Procedures:

• Use hydraulic removal pullers wherever possible. • Adapter sleeves over 150 mm shaft should be ordered with oil injection holes to enable safe and

fast removal by high pressure oil injection.e.g. Sleeve number OH 3134 H • Avoid grinding right through a bearing inner ring and damaging he shaft - inner rings can be

cracked with a cold chisel and hammer if a grinding cut is made nearly all the way through.


3.3 Replacing Sealed Bearings: • Improved life can be achieved when Ball Bearings with double shields (2Z) are converted to the

double sealed (2RS) type. The 2Z bearings are suitable for light-duty environments where low friction is required whereas 2RS types have higher friction but give better protection from moisture and contamination. e.g. small electric motors. e.g. 6305-2Z replaced by 6205-2RS


4. Meeting #3 - Best Practices in Bearing Lubrication Alan Pycroft gave us an excellent overview of the Lubrication practises at TRUenergy - Yallourn. Yallourn has implemented many of the best practices that are mentioned below in the summary. The Presentation is available on the SIRFRt web site www.sirfrt.com.au Go to Meetings, CIWG Meetings, Rolling Bearing Management & Reliability CIWG, Nov 30

4.1 Personnel: • For an effective lubrication program, it was agreed that there must be dedicated Lubrication

person or team to do the job. It should not be a job relegated to the least skilled people on site. • A starting point is to have a job specification and a title for the role that reflects its importance.

e.g. “Lubrication Technician”. If the role is not given importance, it will not be treated with the importance it deserves.

• Where companies have different personnel responsible for lubrication and each area does their own thing, there is no chance of a successful lubrication program. Where the lubrication role is part of a plant-wide strategy for improving lubrication, there is greater chance of implementing a successful program.

• Whoever is involved in the program requires training – not just in the theory of lubrication but in storage, handling, and the various methods of application, safety, and disposal.

4.2 Storage and Handling:

• Try to ensure that a first-in/first-out (FIFO) system is used for drums. • Drums and containers should be stored in clean and dry locations away form all types on

contamination including dust and humidity. Ideally, drums should be stored horizontally on storage racks. With the bungs at 3 and 9 o’clock positions to below the lubricant level.

• Drums should not be stored outside where water can pool on the top of the drums. Water ingress from uncovered drums is a common source of contamination.

• If drums have to be stored outside, it is stongly recommended that they be covered by a shelter. • A separate store for storage of lubricants is best practice. Several companies have done this

already. • Storage areas should have built in spillage areas to prevent spills from contaminating ground

water and the working areas. • It is essential that safe and ergonomic handling equipment is used for lifting, rotating moving,

and handling drums. • The use of 10 litre Oil Safe containers is a good way of reducing the risk of cross contamination

of oils, and can make filling containers faster and more efficient. • Avoid galvanised containers as oil additives may react with the zinc plating causing the

formation of metal soaps that can clog up lube Systems. • Colour coding and clear labelling of drums, containers, hoses, and pumps reduces the risk of

cross-contamination and dispensing the wrong lubricant.


• Oil containers should be stored in metal cabinets in they are not in a clean dedicated lubrication

store. • Each type of Oil should have a dedicated pump to reduce cross-contamination. • Desiccant breathers on drums are a good way to keep oil clean and dry while in storage. • Oils should be filtered (3 micron absolute) when transferring from bulk containers to dispensing

containers. • Bluescope Steel tests new oil delivered from their supplier and has found quality issues that we

not known to the supplier. • Disposal drums should be clearly marked so that oils are not mixed. Mixed oils (e.g. synthetic

and mineral oils) can cause serious problems during disposal or reclaiming.

4.3 Safety: • MSDS must be readily accessible for all lubricants. • The handling of lubricants does have some health risks and appropriate safety procedures

should be followed (e.g. gloves). See table below.


4.4 Training:

Training courses identified by participants are: 1. Noria.

Noria is an independent Lubrication Knowledge company based in the USA. They run courses on Oil Analysis and Machinery Lubrication. The courses are usually followed by optional assessment with an IMCL (International Council for Machinery Lubrication) certification exam. See: www.noria.com for training course dates for Australia for 2006.

2. Vendors: Mobil run an accredited course called Mobil Motion training in conjunction with the VUT (Victoria University of Technology) which is recognised nationally. See appendix for details.

4.5 Flushing of Gearboxes: • One suggested method is to flush a gearbox with a compatible low-viscosity oil variation of the

service oil. • Filter carts are good for flushing gearboxes on line. • Depending on the gearboxes age and the level of contamination and scaling, solvents can be

used which break up the deposits that normal flushing does not remove. • Some companies do a pre-flush and then a final flush.

e.g. Castrol Solvent Flushing Oil • Solvent cleaning may incorporate hydrocarbon-based Solvents (type USDA A-1) like kerosene

or USDA A-2 cleaners such as naphtha and Stoddart.

4.6 Labelling:

• Tags should be used to indicate the correct lube -Grease or oil for the lubrication point. • Some companies use Silastic or Sikaflex to ensure adhesion for labels. • Others use TRAFFOLITE engraved labels

4.7 Relubrication Quantities:

• OEM recommendations are a good place to start. • History and experience is used to fine tune relubrication quantities. • The best way is to calculate the relubrication amount required by using a calculator as

supplied by the bearing companies. (e.g. SKF Dialset or Lubeselect and FAG Relubrication Calculator).

• Bearing catalogues also give the relubrication amounts as a calculation of the bearing size, type, and speed.

• Using listening devices, vibration measurements (e.g. HFD, SEE) and temperature are a good way of determining when a bearing requires relubrication.


4.8 Rationalisation: • When it is done correctly, lubrication rationalisation can have good benefits such as reduced

inventory, reduced risk of applying the wrong lubricant, efficiency, and improved reliability.

• PPG have reduced their greases on site from eight types to one, using Molub-Alloy Multiservice grease 860-220-2,

• The rationalisation program must be driven for the right reasons, not just for cost reduction in purchases. Before rationalising, the details must be checked to ensure that the right lubricant is specified in the first place.

• Involve the supplier in the rationalisation process. • Do not reduce the viscosity of the lubricant when rationalising as this can greatly reduce the

life of bearings and gears.

4.9 Automatic Lubricators:

• The key to success with automatic lubricators (PermaLube, System 24, Memolube, etc.) is to ensure that they are part of a lubrication program that is managed by a CMMS or stand alone lube program.

• Automatic lubricators generally operate well as long as they are used within their range of suitable applications (temperature, length of line, correct relubrication interval, etc.).

• Installing fixed grease lines to make greasing more accessible gives good results.

4.10 Software and Scheduling: • It was generally agreed by the participants that Lubrication Management needs to be run as

a stand alone activity, separate to the main CMMS. This is because the detail required for lube scheduling is too detailed for a CMMS.

• The main methods used are: • Lube- IT see www. www.generationsystems.com • LMS2000 see www.totalplantcontrol.com • In house programs using Excel, Access, etc.

4.11 Magnets, Breathers and Purge Holes:

• It was agreed that Oil Magnets have their place to help make decisions regarding machine problems when used along side Vibration analysis and Oil analysis.

• Oil magnets are common as drain plugs in the automotive applications where no other oil analysis is performed.

• They have proved to be successful for slow speed applications where vibration analysis has been uncertain.

• Yallourn is going to test a couple out to see if they have more universal use. Breathers are good addition to oil lubricated machines as they can keep out both contaminants and moisture if selected correctly.


• Recommended specifications are for filters to have 3-5µ absolute (suppliers are Pall or Hydac) and for desiccant to be included for moisture removal.

• Grease purge holes are important for bearings at high speeds where over lubrication can be a problem (e.g. electric motors and fan housings).

• The SKF and FAG catalogues specify the correct hole sizes for different Plummer blocks and the housings can be ordered with the holes pre-drilled.


5. Meeting # 4 - Root Cause Failure Analysis & Reliability Improvements

PPG Industries was the host company for the meeting on Root Cause Failure Analysis & Reliability Improvements. PPG is the world’s largest OEM automotive coatings supplier, manufacturing water and solvent based paints, coatings, and finishes.

Participants were give a very interesting tour of the plant and were all surprised at the size of the plant and are now much more aware of the PPG brand and the extent of their operations at Clayton.

The site was a good venue for discussing rhe different approaches that companies have to investigating and improving bearing related failures.

5.1 Summary of Companies RCA processes and improvement methodologies

There is a varied range of approaches to reliability improvements,

Company RCA methodology Comments

Impact Fertilisers No formal RCA processes used on site

No full time predictive maintenance personnel. PdM work outsourced to Vipac. Use FAG bearings for low speed applications and SKF for high speed applications. Most problems with bearings are related to sealing, as the environment is very dusty. Have used CARB bearings successfully on fans with life now 5 years from installation.

Qenos Use Formal RCA for major incidents. e.g. shutdowns > 4 hours or costing high $. Have been trained in Taproot, Apollo and Kepner-Tregoe

Have sorted out problems with OEM designs where lubrication ducts have been incorrectly designed. Most problems have been lubrication-related (e.g. Decanter bearings).

Bluescope/Silcar Most bearing failures investigated by reliability personnel.

Use CBC engineers under the contract arrangements to assist with training and failure investigations. Most problems are associated with maintenance installation and inconsistent lubrication practices across the site. Issues with training and quality of tradesmen /fitters are a major concern.

TRUenergy – Yallourn

Use Apollo methodology after generating losses reach threshold.

Estimated that 90% of problems are process and procedure related. Skilled engineering are responsible for installation work and procurement. Have an ITP (Inspection test plan) and ITC (inspection check test). Use CBC and FAG for technical support.


Company RCA methodology Comments

International Power – Hazelwood

No formal RCA process. Reliability personnel get involved in failure analysis.

Most bearing replacements are on white metal bearings on pumps. Small process pumps are replaced, rather than overhauled.

Australian Paper RCA is driven by the size of the problem, when there is a loss of production.

Many problems picked up by Predictive maintenance team. Often bearings are destroyed or disposed of before they can be inspected.

International Power – Loy Yang B

Started using RCA Rt software to record failure data.

Used to use Shell Services for RCA but now do it themselves. Vibration analysis is a major indicator of problems. Have used SKF for mill bearing inspections.

Anglesea Power Station

No structured RCA process. Just starting using RCA Rt.

Have recently had failures on 2 x Sumitomo Cooling Tower Gearboxes, which are as yet undetermined. Use CBC for tech. support as part of a supply contract.

PPG No Formal RCA process. Do oil analysis and Vibration analysis to detect most problems with rotating equipment. Have used SKF for tech. support when required. Generally have high reliability and few problems.

5.1.1 Best Practices in Bearing Reliability Improvement The Best Practices in Reliability Improvement appears to be:

1. Use an RCA investigation to determine the cause of the problem.

2. Investigate options to remove the cause, redesign, or employ new technology

3. Involve the product supplier or contracted vendor engineers for expert assistance.

4. Analyse the cost-benefit of the solution(s) to justify the choice and changes.

5. Get approval if necessary and implement the changes

6. Document the changes (not forgetting to update records, drawing mods, procedures, inventory codes, specification change documentation, etc.)

7. Review the results.

5.1.2 Specific Bearing Failure Information The reference material list on page 23 gives a list of some of the resource material used by participants for bearing failure analysis.

The ISO standard for rolling bearings - Damage and failures - Terms, characteristics, and Causes has now been published and is available. ISO 15243:2004.

When this is used by industry, it will ensure that all parties use the same language when reporting on bearing failures.


5.2 Case Studies of Improvement Projects

5.2.1 Bluescope Steel Rod Bennet from Bluescope Steel gave an excellent presentation on Fan Bearing Reliability Improvements.

By analysing the loading conditions on fan bearings, Rod has been able to select the best bearing and housing options for fans, particularly for overhung fans.

The main fan arrangements are shown below:

He discussed how when using spherical roller bearings, that the bearing carrying the axial load should also be subjected to radial load to improve the load distribution within the bearings. This determines at installation which bearing is the fixed one and which is the floating one.

For overhung fans, especially those with direct drives, the best solution is to have an in-line bearing (two-bearing) housing, because many of the loading conditions can be accommodated better. See Technology upgrade section below for more information. In the case study that Rod presented to the group, the solution to the overhung fan problems involves the installation of an on-line monitoring system to detect early problems (including electrical faults.).

Direct Drive – Centre impeller Pulley Drive- Centre Impeller

Pulley drive - Overhung Impeller Direct Drive – Overhung Impeller


The solution has been in operation now for over 7 years, and the accumulated saving in maintenance costs, production and downtime are now in excess of $1million

5.2.2 TRUenergy Yallourn – Pulley Housing Redesign

Danny Shine from TRUenergy gave a good example of a successful redesign to an inherent original design and manufacture problem with conveyor pulley take-up housings on the Krupp mine dredges. By changing the pulley design from a rotating shaft to a fixed shaft and rotating pulley, they were able to eliminate a misalignment problem that was causing early and frequent bearing failures.

The sealing was also upgraded from a simple labyrinth to a taconite seal (with labyrinth and V-ring), to reduce ingress of contamination. Addition lubrication lines were added to grease the seals as well as the bearings.

The result is an accumulated saving of hundreds of thousands of dollars in maintenance and downtime costs.

5.3 Supplier Technical Support It is agreed that one of the best sources for assistance in technical information on bearing failures and assistance in reliability Improvements is the technical representatives from the various bearing companies. A summary of engineers known to be able to provide good support are as below. In each instance it is advisable to get to know your local contact so that they become familiar with your site and should be more receptive to giving you support.

Company Contact Person (s) Phone CBC Anthony O’Keefe 9276 9100

CBC Laurence Camenzuli 9276 9100

CBC Jeff James 9276 9100

SKF Val Guerra 0417 399 905

SKF John Mesiti 0408 3660498

SKF Rob Distil (Tasmania) 0419 523 959

FAG Craig Edwards 0400 255 187

FAG Milos Grujic 9859 8020

FAG Dana Romanowski 0419 613 956

Two bearing housing for overhung impeller. – Better reliability than 2 x separate Plummer blocks


NSK Nitin Verma 9764 8302

NSK Alan Bampton 9764 8302

TIMKEN Brad Kemp 9541 8101

5.4. Technologies that can improve reliability There are many new technologies available from bearing companies to improve service life. Some are related to steel quality, some to micro-internal design, some with respect to sealing, and some to increased capacity from geometry of rollers and flanges. The improvements can range from small percentage life increases to multiple life increases. The following three examples are technologies that can make dramatic life improvements, where it is not unusual to have increases in MTBF of 10 or more.

5.4.1 Two-Bearing Units for Fans Rod Bennet from Bluescope Steel gave an excellent example of a reliability improvement for fans with overhung impellers. Fans often had variable axial loads s and relatively low radial loads on the bearings. This does not always suit the traditional arrangement of self-aligning bearings in Plummer blocks.

For these overhung fans, a two-bearing unit shown above can have many advantages over a normal arrangement of 2 x Plummer blocks, such as:

• More choices in the bearings that can be installed (ball, angular contact, cylindrical, spherical or CARB, depending on the load and speed).

• Better seals can be fitted to the housings to keep out contamination. • They can run with grease or with oil lubrication. • They have easy installation, because it is only necessary to bolt the unit to its support surface.

(although its necessary to watch out for soft foot) • There is little risk of contaminating or otherwise damaging the bearings during installation.

These units come in standard sizes from SKF and FAG but can be made to suit most existing fan centre heights. Original equipment manufacturers, such as Flakt-Woods, can offer these with new fans installations if you specify them.


5.4.2 ConCentra (Pop-Release) Bearing Units.

These have been around for some years, but still prove to be a good economical technology improvement for some applications. Their main use is in reducing failures caused by contamination and installation. These are bearing units that come complete with the housing, bearing, seals, locking sleeve, lubricant and are pre-assembled, ready to mount. They are quick and easy to install. Once the bearing is correctly located on a shaft, mounting screws are tightened, axially displacing two paired precision-engineered serrated rings. The paired rings grip the shaft as the internal clearance in the bearing is reduced and expand evenly around the entire shaft circumference for a reliable fit. The versions with spherical rollers (as per the picture above) are best used on slower speed applications. They come in fixed and floating executions. There are versions available with ball bearings for lighter loads and higher speeds Their advantages include the following:

• Can be retrofitted to suit many existing shafts and Plummer block sizes. They can often replace standard size Plummer blocks (e.g. SN, SNA, SNH, SNL series from 35mm to 75mm shaft size).

• They have tight gripping triple-lip seals, which are good for keeping out contamination. • No special tools required – just an Allen Key that comes with the bearing unit. • They are protected against contamination during installation. • They allow logistics costs to be reduced as only one part has to be ordered, stored and managed

Application areas Typical applications for these bearing units are mining and metallurgical equipment, quarries, belt conveyors, bucket elevators, refining equipment and chain conveyors.


5.4.3 CARB Toroidal Bearings

The rollers of the CARB bearing are self-guiding, i.e. they will always adopt the position where the load is evenly distributed over the roller length - irrespective of whether the inner ring is axially displaced and/or misaligned with respect to the outer ring. The load carrying capacity of the CARB bearing is very high even when it has to compensate for angular misalignment or axial displacement, which should result in improved reliability. They are intended exclusively as non-locating bearings. They simplify the bearing arrangement design for long shafts that are subjected to temperature variations. When using CARB bearings, it has also been proven that vibration levels are reduced, e.g. in paper machines or fans.

CARB bearings have a lower required minimum load than equivalent sized spherical roller bearings, which means they are less inclined to skid under light load and high speed. Because they require less grease than equivalent sized spherical roller bearings, they can be prone to get hot if too much grease is applied at start-up. Their main uses have been in paper mill rolls, fans, pinion shafts, crushers, and gearboxes.

CARB bearing on Floating end only

The CARB bearing is a single row bearing with long, slightly crowned symmetrical rollers. The raceways of both the inner and outer rings are concave and situated symmetrically about the bearing centre. They have been around for about 10 years now and have started to become a standard bearing for heavy-duty applications.


5.5 Cost-benefit analysis

An important, and often neglected part of a reliability improvement project is the cost-benefit analysis. This is a useful tool in documenting both the projected pay-back time for an improvement as well as historical evidence of the improvement.

This is a key aid in getting management approval for capital or additional resources to fund improvements. An example of a simple cost-benefit analysis is below:

Reliability Improvement Cost-Benefit Analysis Comments Project FD Fan #2

Problem Description Unacceptable failure rate Bearing Failures on average 2 times per year

RCA Outcomes Bearing sealing design and relubrication system is inadequate

Proposed Solution Upgrade bearing housing and seal design and install automatic lubrication.

Maintenance Costs Parts $2,500

Labour cost per hour $35 Number of man hours (elec. + mech) 18

Consumables $250 Other costs $150

Total maintenance cost allocated to repair $3,530

Production Losses Hours of downtime 8

Cost per hour $3,000 Other losses $1,200

Total Production Losses per failure $25,200

Total Cost per event $28,730 Frequency of failure per year 2

Total cost per year $57,460

Improvement costs New Lubrication system $4,900

New shaft $3,200 Drawing and documentation updates $450

Bearing & housing upgrade $750 Other costs $200

Reliability Improvement Costs $9,500 Cost per month if left as is $4,788.33 Average cost of failure per month over one year

Time to pay back improvement costs (months) 2

If the solution extends the MTBF by 2 months, it has paid for itself.

Total Pay back time (6 + 2 months) 8 After 8 months operation, the solution is cost-neutral.

Probability of success >90% Based on other similar improvements documented by vendor.


Appendix 1 - Meeting Dates & Locations

CIWG Date

Meeting Location Main Topic(s)

October 12

Bluescope Steel – Hastings

Training & Installation

November 30

TRUenergy – Yallourn

Lubrication

February 8

PPG - Clayton

RCA & Reliability Improvements

April 5

PowerWorks - Morwell

Stock, Suppliers & Stores


Appendix 2 – Company Attendance List

Company Name Aug-17 Oct-12 Nov-30 Feb-08

Alcoa World Alumina v

Anglesea Power Station v

Australian Paper - Maryvale v v v

BlueScope Steel Limited v v v v

Cement Australia v

Impact Fertilisers v v v

International Power - Hazelwood v v v v

International Power - Loy Yang B v v v v

Mobil Refining Australia Pty Ltd v

PPG Industries v v v

Qenos Australia Pty Ltd v v v

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Appendix 3 - Reference Material Installation & Training Mounting Instructions www.skf.cm/mount 10 Tips for Bearing Maintenance SKFRBO2016 Tips for Bearing Mounting SKFRBO2017 Bearing Basics – an overview SKF RBO2002 Bearing Dismounting Methods SKF GSO4012 s Proper practice for the cleaning, removal NTN9102/E and mounting of bearings Spherical Record Fitting Sheet CBC QA-FGR-01 Self –Aligning Ball Installation Procedures CBC Tapered Bore SRB Measurement NTN Course in Bearing Technology & Maintenance www.skf.com.au Best Practices in Lubrication Oil Safe Products www.oilsafe.com..au Training Courses www.noria.com Lube- IT Software www.generationsystems.com LMS2000 Software www.totalplantcontrol.com Mobil Lubrication Course Michael Lennon - 03 9286 5076 Bearing Lubrication SKFJMO2006 Best Practices in Flushing Gearboxes Noria – Lubrication Excellence Conference 2003 Best Practices for Lube storage & handling SKF Aptitude Exchange Consolidating Lubricants Utility Service Associates Lube Practice – Let’s get Serious Noria – Asset Management 2005 Conference How to set optimum cleanliness levels Noria Pacesetter Performance through sound Premcor Refining Group Lubrication Practices How to design a World Class Lube Room Clopay Corporation RCA & Reliability Improvements Rolling bearings - Damage and failures - Terms, characteristics and causes ISO 15243:2004 NSK Bearing Doctor www.nskaustralia.com.au/page/6view.html SKF Rolling Bearing failures and their causes Product Information 401E FAG Rolling Bearing Damage Publ. No. WL 82 102/2 EA SKF POP release bearings Publication 4255E Rolling Bearing Handbook & Trouble shooting Guide Raymond A. Guyer, Jr. Rolling Bearings in Service – Interpretations of Types of Damage T.S. Nisbet &G.W. Mullett Root Cause Failure Analysis R. Keith Mobley Root Cause Analysis Handbook RCA Rt, SIRF Roundtables SKF Bearing Inspector www.aptitudexhange.com Two Bearing Units www.aptitudexchange.com NSK www.tec.nsk.com Bearing Detective www.emersonbearing.com

best practices in bearing reliability - ciwg minutes.pdf

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