EMS OCTOBER 2010

3

Engineering Maintenance Solutions, June 2010

3

Contents

Publisher - Michael Dominguez

Email:[email protected]

Editors/Contributers - Jon Barratt,Christer Idhammar, Alan France, MickSaltzer, Mark Haarman


Ad Manager - Paul Clappison


Online Sales Director - Paul Miles


Website:

www.engineeringmaintenance.info

MSL Group, Cobalt House, CentreCourt, Sir Thomas Longley Road,Rochester, Kent, ME2 4BQ

Tel: +44(0)1634 731646

Fax: +44(0)1634 731644

www.engineeringmaintenance.info

70/30 PHENOMENON - 5

SHIP BASED CONDITIONMONITORING - 6

LATEST NEWS & PRODUCTS 8- 33

GAS TURBINE

MAINTENANCE - 33 - 38

HEALTH & SAFETY 44 - 47

PLUS:

BUYER’S GUIDE

VIBRATION MONITORING

IR/THERMAL MONITORING

MAINTENANCE BESTPRACTICE

HEAT EXCHANGERS

+ MORE

October 2010

5

All over the world, the mostcommon answer, after someanalysis, verifies that about30% of the people do 70% ofthe work. This is not only true

for front line people like mechanics andelectricians, but also for planners,engineers, and other salaried employees.However, our focus in this column is onthe front line of maintenance.

When I am involved in assessingmaintenance performance for acustomer, I always make an effort totalk one-on-one with individuals, but Ialso talk with a group of three to eightindividuals. When you talk with peopleone-on-one, they are in most cases veryopen and honest about what they say.When you talk with a group of more thanthree, there will often be a change inattitudes.

In a good work system with ahomogenous group of strong performers,there is not much difference in talkingwith people in a group or on anindividual basis. However, in a typicalwork situation, it is common to see a bigdifference.

What I call "the griping level" is very highin a typical group. For example, in agroup of nine, it is likely that threepeople will talk and complain about allthe bad aspects of working in their plant,three people will show signs of supportfor the gripers, and three will say verylittle and remain passive.

I have discovered that the silent few areoften very good craftspeople that belongto the group of good performers, theones doing 70% of the work. They arealso sick and tired of hearing the gripers'constant complaints about everythingthat is wrong, especially when thesegripers never do anything to improve thesituation. As a manager, you shouldremember to listen to the goodperformers and to downplay comments

from the gripers. You should give muchmore time and attention to the bestperformers; otherwise, you risk losingthem.

When presenting observations andrecommendations to a large, mixedgroup of people, I have often brought upthe griping level as an improvementopportunity. After addressing thisproblem, I have had numerouscraftspeople thank me for bringing it up."If we could just get the 70% you talkedabout-and I believe you are correct withthat figure in our organization-to pulltheir weight, we would do very wellhere," is a comment I have heard manytimes from individual crafts people.

I have also had human resource,production, and maintenance managersthank me for addressing the gripinglevel. The fact is that people's attitudeschange quickly after such an opendiscussion, especially after talking aboutthe group they belong to. It is notpositive to be branded as a griper, sothe griping decreases and people starttalking about more productive andpositive issues. Then, when they hearothers say that they do not have enoughresources for a task, their reactionbecomes "we must each do our own partof the work before we complain aboutnot having enough people."

To really change the situation,supervisors or teams must start assigningwork in such a way that all employeeswill have a chance to improve theirperformances. In a team environment,especially if teams are supposed to beself-directed, this can be difficult. Inthe pile of work orders that must bedone, there are always jobs at thebottom of the stack that nobody wants.

As a supervisor, it is understandablytempting to hand work to your bestperformers, because you know it will

get done and you won't need to worryabout it anymore. However, to bring thewhole team up to a high-performancelevel, you must make the effort tomatch the best performers with otherswhen you assign work. It might take alittle longer, but it pays off in the longrun.

The same principle is vital when aproposed flexible work system transfersfrom the negotiated contract to reality.Unfortunately, it is common to see thatafter long negotiations, strikes, andincreased pay, the flexibility agreementis not implemented. Remember that youonly get the flexibility you have trainedpeople for through their workassignments.

Christer Idhammar is a worldrenowned and awarded Reliabilityand Maintenance Consultant andGuru. He is the founder andexecutive vice president withIDCON, INC in Raleigh NC, USA; Areliability and maintenance trainingand consulting companyto industry world wide since 1972.www.idcon.com

70/30 PhenomenonWhen you ask front line supervisors or team leaders if all people in

their teams are performing to the same standards or if some are doingmore work and achieving more results than others, you will often get

the same answer.

6

As a result machinery that isimportant to a vesselsperformance and revenueearning capability may be

monitored only sporadically or notmonitored at all and this falls far shortof best practice.

However there is an alternative to VA fordetecting machinery degradation that iseasy and quick to use by all engineeringpersonnel. It has been in use in generalindustry for almost two decades where ithas proved its effectiveness andsensitivity to faults, giving plenty ofwarning to allow maintenance activitiesto be planned and carried out withminimum disruption to operations andlimiting the opportunity for costlysecondary damage to occur. Furthermoreit is well suited to routine marine usewhere it can put the power of ConditionMonitoring into the hands of every ships’engineer.

Whereas VA requires a sophisticateddiagnostic analysis to be carried out beforethe presence or absence of a faultcan be confirmed, the Acoustic Emission(AE) technique in the guise of aruggedised, portable MHC instrument can

a machine fault and enables easytrending during subsequentdeterioration. Another benefit of the AEtechnique is that it can also monitorslowly rotating machinery whereVibration measurements become evermore difficult because of backgroundnoise issues.

So where’s the catch ? Well although withvery little effort an MHC instrument canlet you know where and when you needto focus your maintenance, it does notdirectly identify the specific nature ofthe fault. In practice this is not as big anegative as it may first appear. Firstly,once you have been pointed in the rightdirection you can often draw on standardengineering skills and experience toidentify the problem and the headphoneson the instrument are a great help in thisregard. Secondly, you could always usethe MHC indication to initiate a fulldiagnostic analysis on just the machine ofconcern at the time it needs it (based onVA and/or AE). However before assumingthis will always be necessary consider thefollowing real life case study from aplatform supply vessel :

MHC instruments are used on a particularfleet of platform supply vessels withperiodic measurements being taken byships’ engineers. On one vessel anincrease in the proprietary Distress®

parameter alerted to a problem arising onthe gearbox starboard alternator PTObearing (in service for 4 years).Measurements over the subsequent 6months tracked the deterioration andstrip-down revealed clear damage withinthe bearing as shown in the accompanyingphotos. The bearing replacement resultedin one planned day out of service.However it was evident that had thebearing further deteriorated considerabledamage would have been caused to thegearbox itself resulting in much greaterrepair costs and a minimum of 7unplanned days out of service. Theestimated saving in this case was well inexcess of £150,000.

In fact MHC instruments are in use onaround 30 platform supply vessels andanother fleet operator whose vessels havebeen monitored with on-board MHCinstruments for the last 7 years summedup the benefits as follows :

“The information that this system pro-

vides to our engineering staff is invalu-

able in being able to plan in advance for

overhauls … It also allows us to vin-

dicate or extend / shorten the manu-

facturers recommended maintenance

schedules based on the data collected

…”.

The MHC range is not restricted toportable instruments and includespermanently installed remote sensors forareas of difficult access as well as stand-alone programmable smart sensors forcontinuous surveillance.

To find out more about an easierapproach to condition monitoring visitwww.holroyd-instruments.com or emailus at [email protected] orphone us on +44 (0)1629 822060.

Easier Ship Based MachineryCondition MonitoringMost engineers acknowledge the usefulness of Vibration Analysis (VA) inthe monitoring of machinery condition and fault diagnosis butunfortunately only a tiny minority have the necessary specialist skills ortime available to apply it successfully.

8

9

With the new SPC DTM datatransfer module fromElcomponent, users of the

company’s renowned SPC range ofportable energy data loggers can nowaccess information from instrumentsinstalled anywhere in the world, withoutleaving their desk.

The SPC DTM module uses GPRS(General Packet Radio Service) toupload logger surveys to the web. Assuch the data is available at anylocation with a PC and an Internetconnection.

For users with data loggers on one ormore remote sites, this means hugesavings in time, money and carbonemissions as it is no longer necessary tovisit those sites regularly to collectenergy data. And, even for users whohave instruments only on their localsite, the ability to acquire data withoutleaving their desks is still a big timesaver and a major aid toconvenience.The new SPC DTM module,which communicates via the same GPRSwireless network that is used to providedata services on mobile phones, upholdsElcomponent’s strong tradition ofproducing devices that are dependable

and easy to use, even for those with nospecialist knowhow.

At the data monitoring location, bethat in an office or any where in theworld with web access, an internetconnection is established using a PCrunning the same PowerPackProsoftware that was used to configurethe module, and the data accessfacility is set up automatically. It’s noteven necessary to enter the webaddress, as the software remembersthis from the programming of themodule.

Unlike general-purpose data loggerpackages, the PowerPackPro softwarehas been specifically designed toprovide energy managers andengineers with the key informationthey need in the form that they needit. It allows, for example, almostinstant creation of graphs and reports,so that energy cost savings andreductions in carbon footprint canstart from day one, and itautomatically converts volume data forgas or oil to energy and carbon valuesand seamless integration withMicrosoft Office.www.elcomponent.co.uk andwww.spcloggers.com

ACCESS KEY ENERGYDATA WITHOUT LEAVINGYOUR DESK!

His Royal Highness spoke to Rich-

ard Granger, Sales Engineer at

Schaeffler (UK) Ltd, to learn

more about Schaeffler’s range of rolling

and plain bearings that are helping engi-

neers to design more energy efficient

wind, wave and tidal turbines.

HRH cut the ribbon at the very first Start

Wales Festival. The event featured pres-

entations and exhibits on the simple steps

we can all take to make better use of our

natural resources, including energy,

food, transport, buildings and waste – at

home and in the workplace.

More than 160 exhibitors attended the

event, including

Schaeffler (UK) Ltd. A variety of different

rolling bearings and plain bearings were

displayed on Schaeffler’s stand, many of

these designed to support specific types

of renewable energy systems, including

wind, wave and tidal turbines.

Prince learns about energy efficient rollingbearings at Start Wales Festival

10

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Cooper Roller Bearings is the inventor and world leader inthe design, manufacture and development of split rollerbearings and has been leading the market for over 100years.

With worldwide representation, vast experience and unbeatableknow-how, Cooper is a full-service provider from bearingselection through installation, training to maintenance andrepair.

Our manufacturing plant is in King’s Lynn where the reliability ofCooper products and business processes is underlined by ISO 9001and 14000 accreditation as well as registration with Lloyds andBSI.

The Cooper split roller bearing is a simple product that can saveyou huge amounts of money by reducing downtime andincreasing productivity. The split feature means inspection andmaintenance is cut to a minimum while the superior sealingpromotes longer bearing life. As a result, your businessprofitability is increased.

When placing an order, please quote this code:engineeringmaintenance2010

Cooper Bearings GroupWisbech Road, King’s LynnNorfolk PE30 5JX, EnglandTel.: +44 (0)1553 763 447Fax: +44 (0)1553 660 494Website: www.cooperbearings.com

EXCELLENCE EVERY INCH OF THE WAY

The problem on the original

bearings, as identified by an NSK

applications engineer, was the

ingress of concrete dust. This is a

common problem in the industry: the

dust combines with bearing lubricant to

produce an abrasive mixture that causes

premature bearing failure. In this

instance, the dust- contaminated

lubricant was causing failures four-times

per year, each failure resulting in 8-

hours downtime, at a cost of €1,200/hr.

As a means of overcoming the problem,

the NSK engineer recommended using

bearings equipped with Molded OilTM, a

solid lubricant technology developed by

NSK for bearings used in remote

locations, and/or where oil and grease

absorbing dust is produced.

Molded OilTM has been proven to

transform the performance of bearings

used in machinery and equipment - in

terms of reliability, maintenance free

intervals and operation - in environments

exposed to contamination. It also

enables plant operators to make real

cost savings by replacing existing, and

often costly, methods of lubricating

machine parts.

A highly effective lubrication method,

Molded Oil differs from other oil impreg-

nated plastics - where the oil content is a

mere few percent by weight - by offering

a lubricating oil content of more than 50%

by weight. This enables the material to

always maintain a good lubrication re-

gime, helped by the mechanism of oil

discharge from the matrix, which this is

temperature dependent: so the higher

the heat generation, the higher the oil

discharge rate. Operating temperatures

are normally limited to 60°c

www.nskeurope.com

NSK’s asset improvement programme has delivered an annual cost saving of€38,400 for a manufacturer of concrete pipes. This has been achieved byreducing failures on the blade support roller of a concrete pipe-slottingmachine, replacing the original bearings, which were lasting 2-3 months onaverage, with NSK Molded OilTM bearings. To date, these bearings haveoperated for 12-months with not a single failure.

NSK’S MOLDED OILTM BEARINGSDELIVER SAVINGS IN DOWNTIMECOSTS OF €38,400/yr FORCONCRETE PIPE MANUFACTURER.

14

New Look, one of the nation’s

hottest fashion chains, has

taken the lead on sustainability

at its new flagship Oxford Circus store on

London’s Oxford Street and its popular

Marble Arch premises, by installing

revolutionary AC Series air curtains from

Airbloc.

The energy efficient Airbloc air curtains

will slash the energy consumption of the

two stores. Situated above the main

entrances, they will reduce

the demands of air

conditioning by preventing

heat loss from the building

by 80%.

The significant green benefits of

installing AC Series units are matched by

their other performance qualities. CE

approved, the versatile and hardwearing

system can be installed either vertically

or horizontally at doorways and

entrances to meet any need.

At New Look’s Oxford Circus store, the

main entrance featured overhead High

Capacity ACR Series air curtains for

additional power.

For the Marble Arch store building,

bespoke AC Series units were supplied. A

corner entrance, it was specially

designed to create an impressive effect

for customers. As such, it was essential

that the air curtains fitted the design

seamlessly.

For further information, please contactMr Keith SpragueFens Pool AvenueBrierley HillWest MidlandsDY5 [email protected]

GREEN IS THISSEASON’S COLOUR

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Confusion often arises over the

difference between mass and volume

flow measurement and when a

particular measurement should be

applied.

Though both technologies will deliver

almost identical results under certain

conditions, the deviations that can oc-

cur where a process is subject to pres-

sure and temperature changes makes it

crucial to make the right choice from

the outset. Understanding the effects

of these deviations and how to correct-

ly select the right flow variable can

lead to significant improvements in

process performance and cost effec-

tiveness.

The video tutorial is presented by Mark

Allinson, Process Flow Specialist for

ABB's UK instrumentation business,

who explains the differences between

mass and volume flow measurement

and highlights the best technologies for

specific applications.

As a leading manufacturer and supplier

of a comprehensive range of flowmeter

technologies, ABB is well placed to of-

fer advice and guidance on the best

flowmeter for your application. For

more information, please call 0870 600

6122 or email

[email protected] ref.

'mass v. volume flow'.

New ABB online tutorial explainshow to choose between mass and

volume flowABB has released the latest in its series of online tutorial videos at

www.youtube.co.uk/abbukinstrumentation, explaining the difference betweenmass and volume flow and how to decide which technique is appropriate for

particular applications.

As it replaces the energy normallyused to fuel boilers or heaters, itsaves significantly on fuel costs.

Energy Box provides an easy to installpackaged system that can be fitted toany make of oil injected rotary screwcompressor up to 90 kW.

It recovers energy from the oil circuit onthe compressor via a heat exchanger,allowing a return on investment (ROI) tobe achieved very quickly.

The amount of energy it is possible torecover using Energy Box can besignificant.

For instance, with a relatively small 37kW compressor, the energy available forrecovery can be up to 29.9 kW. whichmay equate to annual heating costs ofover £6000 (based on 4000 operatinghours if conventional heaters or boilersare used to provide this energy).

The system is available in several sizesto suit any make of oil injected screwcompressor from 11 to 90 kW, andoperating with larger compressors or forlonger periods can result in greaterenergy savings.

Further information:http://www.alup.co.uk/energy-

box.htm

Recovering waste heatfrom compressed air

systemsABAC’s Alup Energy Box converts the

heat generated by most aircompressors into hot water up to 70ºC, for industrial

processes or washroom use.

16

Seaward’s latest PAT accessory is aspecial new adaptor for RCDtesting. The adaptor has beendesigned to enable users to test a

portable RCD or RCD protected extensionlead without risk of tripping the main RCDin the installation.

RCD testing has taken on greatersignificance since the introduction of the3rd Edition of the IEE Code of Practicewhich recommends that when anextension lead or multiway adaptor isfitted with an RCD, the RCD should bechecked using an RCD test instrument todetermine that the trip time is within thelimits set out in BS 4293, BS 7288 or BS EN61008.

Most Seaward portable appliance testersare already equipped with an integral RCDtrip time test. However, when testing aportable RCD using a mains outlet on an

installation which is RCD protected, thetest may cause the main RCD to operate.

The new compact RCD test adaptoreliminates this problem by providing anisolated mains supply. The Seaward RCDadaptor can be used easily and effectivelywith any make of PAT tester or RCD testinstrument.

The new RCD test adaptor from Seawardforms part of an extended range ofspecialist PAT testers and accessories.

More details from: www.seaward.co.uk

TEST ADAPTOR AVOIDSUNWANTED TRIPPING OF RCDs

“Customers also get one freecast metal sanding or grindingconnection manifold and one

hundred free abrasive discs,” said MarkHodgens, Managing Director. “It’s acomplete package, ready to use - all at agreatly reduced price.”

The P160I is available in 110V or 240V.The 1200W motor gives powerfulperformance from a light unit (19kg)that’s ideal for most general sanding andgrinding applications. Automatic featuresinclude electrical start / stop and filtercleaning; a floor cleaning attachment isalso included.

This versatility makes it an ideal entry-level extraction solution for businesseslooking to realise benefits includingreduced abrasive costs, improvedproduct quality and lower cleaning costs,all whilst protecting staff from harmfulparticles.

Further information is available atwww.nederman.co.uk or by contactingNederman on 08452 743434.

Nederman’s Free GrinderNederman are offering a free high quality sander /grinder with all P160I portable dustextraction units absolutely freefrom 01st September to 31stDecember.

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Maintenance engineers have longknown the benefits ofmonitoring vibration, howeverthe virtues of what can be

achieved are not always appreciated bytheir work colleagues and the validwarnings that are highlighted can bedisregarded from management level tothe shop floor with often catastrophicresults.

Chris Hansford, Managing Director atHansford Sensors Ltd. tells that “Such asituation was reported to us via one ofour overseas customers very recently. AMaintenance Engineer Team leadercontacted our customer directly foradvice on a potential equipment failurethey had recently identified. Theapplication was in a process applicationwhere the Maintenance Team haddiscovered that a conveyor pulleybearing had developed high levels ofwear over a short period of time. TheProduction Department decided that,instead of instigating an unplannedshutdown, based on therecommendations of the MaintenanceTeam they chose to ignore the warningand continued to run the pulley untilthe planned shutdown date. Thescheduled shutdown was due 3 weeksafter the initial bearing faultdetection”.

Chris continues “The maintenance teamresponsible for the monitoring of thisproduction line was obviously concerned

with the possibility of a failure on thispulley, and on the recommendation ofour customer they purchased a stockitem sensor; HS-423 (Dual output -4-20mA acceleration into the PLC and ACoutput via a data collector). Within 24hours these were delivered and installedon the conveyor pulley bearing that hadbeen diagnosed with high levels of wear,thus giving Management at the facilityinstant warning if the problem pro-gressed further”.

As the date for the planned shutgrew closer, the identified ‘g’(acceleration) levels shown by theHS-423 sensor, monitoring thepulley bearing doubled. The HS-423, being connected directly tothe control room display, wassent into alarm as the detectedlevels surpassed previouslyspecified warningparameters. These readingwere further backed up bythe acceleration readingstaken via the department’shand-held data collector.The levels increasedsubstantially in the finalhours before the failure.(See diagram)

Unfortunately, the operators did notheed the alarm warnings and continuedtheir attempt to run the conveyor to theplanned shutdown date. Consequentlythe bearing catastrophically failed, inturn catching on fire and resulting in highcosts of damage to equipment andputting the lives of a number ofemployees at risk. This resulted inexpensive repairs, a mountain of paperwork with the fire it caused and shutdown of the conveyor for over 24 hours.Hindsight is a wonderful thing, but atleast a valuable lesson had been learned.Fortunately no-one was badly injuredand the worth of the Maintenance Teamhas been put in the spot-light provingwhat a valuable job they carry out andthe significance of their role in ensuringthe safe, cost-effective management ofindustrial plant.

For more information, pleasecontact:-

Suzanne PearlHansford Sensors Ltd.

Tel:0845 680 1957Fax:0845 680 1958


Web: www.hansfordsensors.com

Hansford Sensors highlight benefitsof On-line monitoring using HS-423

Dual Output SensorsIn the world of industry, pressure to deliver high productivity whilst keeping

costs down has over the last two decades led to a rise in the implementation ofmachinery vibration monitoring programs with great success. Costly break downsand damage to machinery have in many instances been avoided and the required

maintenance has been able to be scheduled for a convenient time.

22

Listed as a key topic is a SIPOSAktorik case-study on theimplementation of SIPOS 5 variable

speed actuators in district cooling plantsin the UAE: Steffen Koehler, SIPOSAktorik’s International Sales Manager willpresent a paper on this subject on thefirst day of the programme.

The summit has been designed to attractdelegates from a range of sectorsincluding district coolingowners/operators, EPC/MEP andmaintenance contractors along withwater re-use/conservation companiesplus WwTW and power utilityorganisations.

SIPOS will therefore be well placed topresent its district cooling specialism tokey target markets with a display thatwill highlight how its actuators controlcooling water flow and protecthydraulics from water hammer.

Successful district cooling installationsfor SIPOS in the Middle East includecontracts in Dubai, Yas Island and AlRaha beach.

As well as presenting a paper, SIPOS willhave a presence in the exhibition areasupported by local agent Torento EnergySystems.

SIPOS Aktorik GmbH, Im Erlet 2, D-90518 Altdorf, GermanyTel. +49 (0) 9187 / 9227- 0 Fax +49 (0)9187 / 9227-5111 Web: www.sipos.de

SIPOS takes district cooling toDohaA growing Middle East market for SIPOS Aktorik’sactuation solution for district cooling is beingsupported with a premium gold sponsorship packagefor the DC summit in Doha. The second annualdistrict cooling event will run from 28-30 Nov 2010.

Photocaption: SIPOS actuators aiddistrict cooling

Commonly used on small sensing

devices, the M8 connector has

become popular in recent years,

having developed from a simple push-fit

to more secure screw-on connectors.

While conforming to EN 61076, the de-

sign was, however, ripe for the makeover

now thoughtfully carried out by sensor

market leader ifm electronic Ltd.

Having greatly improved the larger M12

connector, the sensor Specialist Compa-

ny turned their attention specifically to

the seal of the M8. As the male part of

the connector is designed with a taper –

originating from the push-fit days – it

does not always sit well on the O-ring

supplied with the female counterpart,

and in fact can ride up, losing any seal-

ing function. In addition, the small size

of the connector led often to insufficient

tightening of the thread, again leading to

loss of seal of shaking loose. All this re-

sulted in a lack of confidence in the M8

connector in many applications.

Now with the new additions to their

‘ecolink’ family sensor market leader ifm

electronic have successfully addressed

both of these issues at a stroke.

Firstly, the sealing O-ring has been clev-

erly replaced by a profiled seal. Normally

invisible in the female connector, this

seal has a vital role in keeping moisture

out of the connection, but the original

design was not always capable. Now the

cunning new design of shaped seal can-

not be displaced, and will always per-

form. This design achieves protection

ratings of IP 67, IP 68 and even IP 69K

Secondly, the mechanical interlocking of

the two parts is now more stable thanks

to the sawtooth incorporated in the

thread. This prevents the mated parts

from shaking apart under high or pro-

longed vibration.

For further information: Telephone:

+44(0)20 8213-0000. or visit our

website www.ifm.com/uk

Better connections, better seal New M8 connectors from ifmelectronic

23

The detection of defects in

switchgear, fuses, motors or

electrical connections is almost

impossible with the naked eye. But we

do know that almost any electrical

device will get warmer than normal very

soon after an anomaly occurs. In

complement to portable thermal

imagers, high-end portable infrared

thermometers are now increasingly used

for the detection of weak spots.

Fixed pyrometers are used

predominantly in plants where electrical

or mechanical components to be

monitored are hard or impossible to

reach.

Using portable precision pyrometers

for preventive maintenance

The handheld infrared thermometer

optris LaserSight LS enables you to verify

critical components quickly and easily

once you have identified them by means

of a thermal imager. This gives you fast

inspection capability for temperatures

from -32 to 900ºC.

The integrated laser sight with crosshairs

permits accurate targeting of the

measured object and indicates the real

measurement spot size.

At the touch of a single button the

temperature reading appears on the

display with a 0.1ºC resolution. An alarm

signal is output to indicate temperatures

above or below programmed limit values

(MAX/MIN function) so that you can

systematically scan the measured object

and quickly pinpoint the source of the

malfunction.

One major aspect to be taken into

account for all measurements is whether

the optics of the infrared thermometer

actually are able to acquire the hot spots

properly. The optical resolution offered

by commercially available infrared

thermometers in the low price range is

poor, and the dot laser featured by such

instruments can be used for sighting only

but doesn’t represent the true

measurement spot size.

As a consequence, the temperatures

readings for overheated objects are

lower than their real temperatures. So

if, for example, a small electrical

component experiences an overload

condition and heats up excessively, this

will only show as a minor temperature

rise if the measurement spot is too large,

so that potentially hazardous situations

will go undetected.

Figure 1 shows a correct temperature

measurement procedure using the

laser/crosshairs technology for

Noncontact temperature monitoring is an essential tool for ensuringthe safety and reliability of equipment. As alternative solutions to

portable thermal imagers, both portable and fixed infraredthermometers are gaining importance in preventive maintenanceapplications, the latter for example in OEM solutions and for the

infrared monitoring of large plants with a multitude of measuringpoints.

RethinkingMaintenance

Procedures Using IR

Fig. 1: Temperaturemeasurements on highlystressed components of awelding robot using theoptris LaserSight LS

24

monitoring of mechanical components on

a welding robot.

The new two-lens precision optics of the

optris LaserSight LS permit the

measurement of very small objects.

Switching to the Close Focus Mode

enables you to accurately measure

targets as small as 1 mm. Sighting is

provided by two laser beams intersecting

at the close focus point at a distance of

62 mm. So far, instruments available on

the market have been designed either

for longer measuring distances, or

exclusively for small measurement

objects. This forced customers to buy

either several thermometer models or

replacement optics. The optris

LaserSight LS is an all-in-one

instrument where you simply flip a

selector switch for close focussing.

Fixed measuring system for full-time

monitoring

In plants which are very expansive or

comprise hard-to-reach electrical or

mechanical equipment (large production

facilities, high-rise buildings, shipboard

systems etc.) the use of portable

instruments is very time-consuming and

labour-intensive.

Also, such inspections can never be more

than random spot checks and will only

permit the detection of trends. Near-

absolute safety can only be offered by a

fixed system providing full-time

continuous monitoring.

The fixed pyrometer optris CS has been

specially designed for maximum

versatility and is used for example to

monitor shipboard electrical systems for

loose bolted connections. Defective

busbar and power breaker connections

lead to increased contact resistances,

causing overheating at these points.

Fixed pyrometers are an affordable

solution for the monitoring of large

numbers of such critical points.

If temperature limits are exceeded an

alarm signal is output to the control unit.

This allows overheating conditions to be

detected quickly and reliably and the

electrical system to be cut-out

instantaneously with very short response

times (less than 1 second).

Fig. 2: Detailed temperaturemeasurement of an electricalcontrol system using theintegrated Close Focus opticsof the optris LaserSight LS

Fig. 3: Medium-voltage switchgearmonitored by fixed pyrometers

25

The optris CS measures temperatures

from -20 to 350°C, being only 87 mm

long and 12 mm in diameter it can be

installed in confined spaces and

tolerates ambient temperatures up to

75°C. It is attractively priced and

combines excellent quality and high

measuring accuracy with a rugged,

superior mechanical design. It has been

designed for deployment in harsh

industrial environments and ensures very

good electromagnetic compatibility

performance. The electronics package is

integrated in the instrument together

with an intelligent sighting aid.

It also features a scalable analog output

(0 - 10 V or 0 - 5 V) and protection

against short circuits and polarity

reversal.

Medium-voltage switchgears fitted with

the instrumentation described above will

no longer require any additional routine

checks of contact points. This improves

the protection of your equipment,

reduces maintenance costs and ensures

the health and safety of your personnel.

For Further information please

CONTACT:

Optris GmbH

Ferdinand-Buisson-Str. 14 · D -13127

Berlin · Germany

Tel. +49 30 500197-0

Fax +49 30 500197-10

E-mail : [email protected]

www.optris.de

Fig. 5: Typical monitoringlocations at points of contact

Fig. 4: optris CS pyrometer

Focusing on customersatisfaction and meeting allrequirements soon saw theorder book grow and by theend of the first year oftrading a firm customer basehad been established and

growth soon followed.Following four years of exceeding allplanned growth projections the businesswas incorporated as a limited companyin April of 2007.

Further investment then enabled there-location to new premises to cater forthe increase in growth demand withinthe market place.

Today that growth continues and furtherinvestment is being planned to be readyto meet future challenges and continueto meet all customer needs andexpectations.

A&G Heat Exchangers Limited is aleading supplier of heating and coolingsolutions. Utilising the most up to datedesign software our engineers are ableto evaluate all customer requirementsand offer the most cost effective designsolutions to ensure effectiveserviceability whilst fully complying withPED regulations.

Along with the annual growth came theability and capability to meet ever moredemanding requirements set by ourcustomers. Detailed above is a servicelist that we currently offer.

Turn key projects including skidmounted equipment and completesupply and installation of pipe work andcontrols Is also part of the service weoffer.

We also specialise in the supply andassembly of kit form heat exchangerswhere there are access restrictions tofinal installation locations.

Welding

All welding is carried out by codedoperators qualified to ASME IX and BSEN 287

Operations

All operations are governed by our ISO9001:2008 accredited status. Supply of aquality service and delivery of a qualityproduct is confirmed by the feedbackwe receive from satisfied customers. Allour systems are controlled inaccordance with the standard and areaudited continually for compliance.

The health and safety of all personsconnected with our operations isparamount. This fact is confirmed by ourcommitment to enrolling with the CHAS -Contractors Health and SafetyAssessment scheme. Our procedures forensuring the welfare of all have beenconfirmed as fully compliant and willcontinue to be so.

A&G Heat Exchangers Ltd welcomes allenquiries. We are fully committed tosupplying a service that fully complieswith all our customer requirements andmeets all needs and expectations.

We look forward to being of service.

A&G Heat Exchangers LimitedTel:00 44 (0)121 788 2450Fax:00 44 (0)121 788 2587Web: www.aandgheatexchangers.com

A&G HeatExchangers Ltd

A&G Heat Exchangers was established as apartnership business in 2003 by two

engineers who saw potential in market share to supply heatexchanger solutions and services. Pooling their knowledge andskills together the business soon established itself and furtherenhanced its capabilities by employing a dedicated team upon

which a platform for growth was soon established.

The VIBXPERT II handheldvibration analyzer combinesthe advantages of a rapidprocessor with a brilliantenergy-efficient colour VGA

display. Enhanced with an Fmax of51KHz and up to 102,400 Lines ofResolution, all machinery problemscan be captured and easily analyzedon the VIBXPERT II large colour screen.

The VIBXPERT II Basic platform is a1-channel vibration data collectorwhich can be upgraded at any time to2 individually configured channels viaa special pass code it’s userupgradable and does not requirehardware changes.

All forms of machine vibrations,bearing conditions, process data andvisual inspection information can becollected and stored on theexpandable Compact Flash Card (up to8 gigabyte) for report generation or forlater transfer to the OMNITRENDsoftware for further analysis,reporting and archiving.

The VIBXPERT II vibration analyzerprovides an easy-to-use icon drivenplatform that offers comprehensiveanalysis functionality for the diagnosisof simple or very complex vibrationproblems. Capabilities include orderspectrum, phase, cepstrum, cross-channel phase, orbits, run-up andcoast-down measurements, bumptest, negative averaging and more.Analysis tools, including various cursortypes, machine-specific frequencymarkers, signal post processing, andextensive bearing databases areincluded for evaluating eachspectrum. Alarm notifications basedon ISO standards or user-defined

standards are visually identified withthe aid of coloured LEDs.

VIBXPERT II is lightweight vibrationmeter —only 1.2Kg! Its robust housingis dustproof and water resistant(IP65). VIBXPERT II is delivered with acarrying pouch with includes abreakaway shoulder strap for safetyduring data collection.

The VIBXPERT II vibration analyzerfeatures modular functionalityincluding dynamic balancing,extended time waveform recording,transient data capture, UFF fileexport, Modal/ODS support and more.

As with all Pruftechnik vibration datacollectors with the new VIBXPERT IIyou will enjoy the benefits of freeupdates, low ownership cost andunlimited tech support from the

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Optionally available:

Modules for Dynamic Balancing,Recording, Modal Analysis andOperation Deflection Shape (ODS) andVIBCODE automatic measurementlocation identification.

For details and our free 180 pageguide to Condition Monitoring, LaserShaft Alignment and DynamicBalancing contactPruftechnik Ltd, Plant LaneBusiness Park, Burntwood WS7 3GNorphone 01543 448350,Fax 01543 275472,email [email protected]

Vibxpert® IIA New Portable Vibration Analyzer — with Full

Colour Display, fast data acquisition andpowerful diagnostics tools.

30

31

PROSIG have already successfullycommissioned and installed thePROTOR system in the Lada(Asturias, Spain) and the Pasajes

(Guipúzcoa, Spain) power plants. Thework primarily consists of the supply,installation and signal cabling of thePROTOR systems together with trainingof the IBERDROLA staff. PROSIG willcomplete the third installation at theVelilla power plant, located in Palencia,Spain in September 2010.

The monitoring and diagnosis of rotatingequipment based on vibration analysismeasurement is at the core of predictivemaintenance systems. This type of sys-tem allows the condition and health ofmachines to be assessed. During opera-tion, rotating equipment experiencesdynamic stress caused by hydraulic, me-chanical or electrical forces that inducevibrations and contribute to both ageingand wear of machines. The damage levelof a rotating machine is reflected in sev-eral measureable factors.

The PROTOR Vibration Monitoring Sys-tem, designed and manufactured byPROSIG, provides reliable on-line moni-toring of turbine generators, main boilerfeed pumps and other auxiliary plantequipment. It provides both real-timeand long-term historical access to theimportant vibration factors togetherwith various plant process parameterswhich indicate the machine state.

Without information on the condition ofprimary equipment, such as turbines,pumps and associated plant, impendingfaults go unnoticed and develop intosevere conditions that could result infailures. Failures may lead to unsched-uled outages or more serious equipmentdamage with consequent loss of reve-nues.

tel: +44 (0)1329 239925

http://www.prosig.com

[email protected]

Protor Vibration ConditionMonitoring System Installed in Three

Thermal Power Plants in Spain forIberdrola

IBERDROLA has launched a renewal plan for the existing condition monitoringsystems in their plants in Spain. This plan will be implemented gradually andPROSIG was selected to install their PROTOR Vibration Condition Monitoring

System in three IBERDROLA power stations. The contract was awarded to PROSIGin partnership with Aries Ingeniería y Sistemas, who are PROSIG’s representative

in Spain.

32

VDV software is used for professionalhandling of data from technicalprojects like Wind Farms, Ambient

Weather and Water and Sewer infrastruc-tures.VDV automatically imports data fromfiles collected from your data-logger(s)

and stores in its built-in database. Withaccess to the database, VDV becomes thefront end of your data allowing you toeasily and quickly view graphs, histo-grams, wind roses and trend lines. Virtu-al variables can be used to create newcalculated results. Validation limits and

alarm limits can beset for individualsensors. With VDV,there are endlesspossibilities of mak-ing logged data visi-ble and easy tounderstand.

Users include Gov-ernment Agencies,Universities, Munici-pals and Engineeringfirms.

Full Web-access to all data is accom-plished using comprehensive Access Con-trol. VDV natively supports the fullrange of Campbell Scientific data-loggersand most other brands of data-loggersvia its File Converter.

See http://demo.vistadatavision.comfor real data from various industries.

For more information, please contactVista Data Vision - Vista Engineering,Hofdabakka 9c,IS-110 Reykjavik, Iceland, tel +354-587-8889email [email protected],www.vistadatavision.com,

If logging data, use Vista Data Vision (VDV) for auto-matic data handling, including data base storage,trend lines, alarms and reports

Vista Data Vision (VDV)

33

Combined Cycle Power Plantswere originally designed tooperate as base-loaded units,however, recently most ofthese units that operate arecycled weekly or daily and

during the day the plants are furthercycled from about 40% - 100% powerload. Most operators and OEM’s work onan equivalent hour basis, which takesinto account the number of starts, andthe percent load and time at which theyare operated. The gas turbine failuresrange from control system problems,which are the most frequent but thedown time accompanying these failuresusually is the smallest averaging a fewhours, the problems with combustors,rotors and blade failures are lessfrequent but the down time and costsaccompanying those failures couldextend to several weeks, and severalmillion dollars in costs. The hot sectionfailures used to far outnumber theproblems in the compressor due to thehigh temperatures associated with thehot section, however in today’sadvanced gas turbine a blade failure inthe compressor can cause extensivedownstream failures.

Recent reports published Based oninformation from “Moderne GasTurbinen-Technologie, Risiken undSchaden, Dr. J. Stoiber, Allianz ZentrumFur Technik Gmbh, VGB PowerTech2/2002, divides the problems for gasturbines into sizes larger than 150 MW,and gas turbines less than 170 MW.Figure 1 and Figure 2 show the majorproblems areas experienced in Gasturbines than less 150 MW and largerthan 150 MW, respectively. In thesmaller size turbines, the problems areconcentrated in the hot section, as hasbeen traditionally experienced. Theinteresting point as seen in Figure 2 isthat the compressor problems are greatlyincreased as the turbine ratings increase.

In fact, the compressor problems areslightly larger than the turbine problems.This is related to the high flow and highpressure in the larger turbines, and theair coolers forcompressor air usedfor turbine cooling.

The failures of thegas turbine in thecompressor sectionare usually in theInlet Guide Vanes, atthe transitionbetween the lowpressure and highpressure compressorsand due to rubbing instages usuallyupstream of the bleedflow sections. Thelarger units have veryhigh pressure ratios per stage, and haveboth low pressure and high pressurecompressors and have high exittemperatures all leading to problems inthe compressor section. The compressor

exhaust air coolers in some systems arepart of the Heat Recovery SteamGenerator Systems (HRSG), addingfurther complexity to the system.

The last twenty years has seen a largegrowth in Gas Turbine Technology. Thegrowth is spear headed by the increasein compressor pressure ratio, advancedcombustion techniques, the growth of

Maintenance of GasTurbines

There are many types of failures associated with a gasturbine, since these units are very complex in their

overall makeup. The Gas Turbines are the heart of largeCombined Cycle Power Plants.

Figure 1 – Major Failures in GasTurbines Smaller Than 170 MW

Figure 2 – Major Failures in GasTurbines Sizes Larger than 150 MW

TURBINE MAINTENANCE

34

materials technology, new coatings andnew cooling schemes. In other words thetechnology envelope is being pushed sothat many of the components areoperating in uncharted waters.

Gas Turbine maintenance is dependent onthe operational characteristics of theplant. The large Combined Cycle PowerPlants were developed as Base LoadOperating Units (1 start in every 1000hours of operation). The reality has beenvery different and most combined cyclepower plants are operating under cyclicconditions where the load at off primetime could be as low as 40-50% of thebase load. Many of these plants nowshutdown for the weekends. Thesechanges in operation in many casesrequire the maintenance and inspectionchanges. Maintenance of most gasturbines depends on Equivalent EngineOperating Hours (EOH) and the number ofstarts. The Equivalent Operating Hours(EOH) are based on calculation of thenumber of starts or stops, number oftrips, firing temperature, the variation infiring temperature, the type of fuel andthe total actual operating hours.

Inspection intervals are in most casesbased on EOH, but some manufacturersalso want to base these intervals on acombination of EOH and number of starts.Table 1 shows the typical gas turbineintervals for various types of inspections.

TABLE 1

Typical Gas Turbine Inspection timeIntervals.

EquivalentOperating Hours

8,000 16,000 24,000 32,000 40,000 48,000

Type of Inspection CombustorInspection Combustorand First StageNozzle vanes andblades* Hot GasPath Inspection CombustorInspection Combustor and First Stage NozzleVanes and Blades* Full TurbineMaintenance

Fired Starts 400 800 1200 1600

Inspection Combustor Inspection HotGas Path Inspection CombustorInspection Full Turbine Maintenance

Performance degradation in a gasturbine can be categorized asrecoverable and non-recoverable.Recoverable performance is thedeterioration in a gas turbineperformance that can be recovered byengine cleaning or other wise known asan on-line and off-line water wash.Non-recoverable degradation is theperformance deterioration of a gasturbine caused by internal enginecomponent wear. The only way torecover the non-recoverabledegradation is by performing a shopinspection and engine overhaul.Deterioration in turbine performance isindicated by one or more of thefollowing conditions:

Slower engine acceleration

Engine compressor surge or stall

Lower power output

Loss of engine compressor dischargepressure

Increase in compressor dischargetemperature

Figure 3 is a typical non-recoverablePower and Heat Rate degradation curve

as a function of Equivalent EngineOperating Hours (EOH). With anincrease in equivalent engine operatinghours there is a sharp drop in delivered

power and an increase in the turbineheat rate during the first 5000equivalent operating hours. Theselosses are non-recoverable in mostcases, and would require the turbine tobe returned to the shop, and outfittedwith most new components, as well asspecial machining of the casing.

Compressor Section

Increase in overall gas turbine efficiencydepends on pressure ratio and firingtemperature. Therefore advanced gasturbines operate at very high pressureratios. Pressure ratios in industrial gasturbines have increased from about 7:1in the 1950’s to as high as 30:1 in thelate 1990’s. Aero-engines in operationtoday have pressure ratios as high as40:1. This increase in compressorpressure ratio decreases the operatingrange of the compressor, and thus thestability of the compressor. Theoperating range of the compressor isdefined as the flow range at a constantspeed line stretches from the surgepoint at the low flow end to the chokepoint at the high flow end. The stabilityof the compressor is defined as the ratioof the difference between the surgepoint and the design point to the designpoint:

Stability (%) = ( Design Point- Surgepoint)/ Design point

The compressor of a gas turbineconsumes over 55%-60% of the powergenerated by the turbine, thus problemswith the compressor can be very costlyas to power produced and the loss ofoverall thermal efficiency of the gasturbine. Figure 4 shows the effect ofcompressor fouling on overall cycleefficiency. The effect of fouling of thecompressor which reduces thecompressor efficiency, leads to areduction in the overall efficiency. Thehigher the pressure ratio of thecompressor, the greater the reduction inthe overall thermal efficiency of theturbine as can also be seen.

Figure 4

Effect of Compressor Efficiency Drop onthe Overall Thermal Efficiency

Reduction

Table 2 indicates the various foulingmechanisms that affect the compressor

TURBINE MAINTENANCE

35

section of the Gas Turbine. The tableindicates the effect that various types offouling mechanisms have on the entirecompressor section from the Inlet GuideVanes to the Exhaust Guide Vanes*. Thetable deals with the effects on thevariable and fixed compressor statorvanes, and the rotating blades.

Table 2

Axial flow compressor performance issensitive to the condition of the rotorblades. The compressor’s majorproblems are caused by dirt on theblades, due to poor filtration andmaintenance practices. On-line waterwashing recovers majority of theperformance deterioration. During amajor inspection, all blades should becleaned and checked for cracks with adye penetrant test. If cracks are foundin any blade, that blade should bereplaced. Occasionally, small cracks canbe blended out, tests conducted onblended blades have shown that if 75% ofthe blade tip chord length is intact thenthe compressor will suffer minimal lossof pressure and efficiency, and theblades can be used. The maximum andminimum chord lengths should berecorded and reported to themanufacturer, who in turn should beable to report the performance lossoccasioned by wear and the decrease instructural strength. Leading edge bladeerosion, as seen in Figure 5, is caused bythe impact of water droplets from inletevaporative and fogging systemscommonly used in large gas turbines asan aid to power augmentation during thehot summer months. It should be notedthat in many cases the benefit ofEvaporative Cooling outweighs the costof rejuvenating the leading edge of theseblades.

Figure 5

Coating Erosion Found on the First Stageof the Compressor Blade in units using

Evaporative Cooling Systems

The trends for the advanced axial flowcompressors are towards fewer, thinner,larger, three Dimensional and controlleddiffusion shaped airfoils (3D/CDA), withsmaller clearances and higher loadingper stage. Table 3 shows the technologyin Axial flow Compressor blading of thenew advanced gas turbines.

TABLE 3

Comparison of Design Characteristics ofthe New Advanced Gas Turbine Blades tothe

Many of the new high performancecompressors suffer from tip rubs. Thesmaller clearances (20-50 mils) and highpressure ratios tend to increase theprobability of encountering rubs. Thesetip rubs can lead to blade failures at thetrailing edge of the tip section of theblades. Most of these tip rubs do usuallyoccur near the bleed sections which areusually positioned around the first bleedvalve section which are close to thefourth to seventh compressor stages andthe second bleed valve section which are

near the eleventh to fourteenthcompressor stages and therefore aremore susceptible to out of roundness ofthe casing. Figure 6 shows the bleedchambers in a typical compressor.Measurements of the casing should betaken to determine blade tip clearancesat eight points on the innercircumference of the compressor casing.Comparison of these clearance readingswith those at installation or at someprevious time will indicate if rubs haveoccurred and whether or not the casingis warped. It will also indicate whetheror not the rotor is below its originalposition and requires furtherinvestigation at the overhaul period..

Figure 6

Typical Bleed Ports in an Axial FlowCompressor

The advancedcompressor bladesalso usually havesquealer sectionson the blade tips,which are designedto wear in a safemanner if theblades are incontact with thecasing. Theserubs, if severe canlead to tipfractures andoverall destructionof the downstreamblades and diffuser

vanes due to domestic object damage(DOD), as seen in Figure 7..

Figure 7

Compressor blade Damage due toDomestic object damage (DOD) due toblade tip failure due to rubbing

The very high temperature at the exit ofthe compressor, which in some casesexceeds 1000ºF (538 ºC), causes a veryhot compression section, which alsorequires the cooling of the bleed flowsbefore they can be used for cooling theturbine section. This also limits thedown time between start-ups of theturbines. Design margins are set byFinite Element Modeling (FEM) at the

TURBINE MAINTENANCE

36

element level which results in lowersafety margins than previous designs.The costs of these larger, thinner, less-rub tolerant, and more twisted-shapeairfoils are usually higher. When severalof the major characteristics of advancedgas turbines are examined from a riskviewpoint (i.e., probability andconsequences of failure), there are nocharacteristics which reduce theprobability of failure and/or decrease

the consequence of failure.

Figure 7 indicates typical blade failuresin blades around the fifth to seventhstage of a typical axial flow compressorin an advanced gas turbine. Note thenumber of blades downstream whichhave suffered from DOD.

If the air inlet is subjected to salt-watercontamination, the rotor and statorblades should be checked for pitting.Severe pitting near the blade roots maylead to structural failures. Themanufacturer should be informed ofsevere pitting. Coating compressorblades is highly recommended and theextra cost is paid back in the first yearby the fuel savings.

On line cleaning is a very importantoperational requirement. On-linecleaning is not the answer to allcompressor fouling problems since aftereach cleaning cycle full power is notregained, therefore a time comes when

the unit needs to be cleaned off-line, asseen in Figure 3

Figure 3

Effect of Compressor Water Wash onPower Output

The time for off-line cleaning must bedetermined by calculating the loss of

income in power as well as the cost oflabor to do so and equate it against theextra energy costs. Cleaning the turbinecompressor with the online wash systemshould be a routine, and scheduledmaintenance function. The on-linewater wash system is based on injectingatomized demineralized water or amixture with a cleaning fluid.

Water quality for both on-line and off-line water washes must be stringent, soas to ensure that impurities are notintroduced. Table 3 gives a detailedspecification of the quality of the water

required to complete a successful waterwash.

TABLE 3

WATER SPECIFICATION

Combustor Section

Gas Turbine Combustors can be “CanAnnular Type Combustors” where about10-14 individual combustor cans arepositioned in an annular configuration.The can annular chambers are connectedto each other by the use of cross-overtubes which are there to ensure that thecombustion pressure is maintainedevenly in all the combustor cans. Theother configuration of the combustor canis a “Single Annular Combustor”.Furthermore each of the above two typecombustors can be classified into twotypes of combustion chambercharacteristics: “Diffusion Type WetCombustors”, and the “Dry Low NOx(DLN) Combustors”, or sometimes knownas “Dry Low Emission (DLE)Combustors”., and furthermore there aredifferent configurations of the combustorchambers, the most common being theannular and can annular combustors.

Diffusion type combustors inject the fuelthrough a single fuel nozzle into theprimary combustion zone where it mixeswith about 8-10% of the compressed airflow, and stoichiometric combustionoccurs. The rest of the compressed air isused for cooling and mixing in thecombustor liner. Water or steam isinjected in the stoichiometric zone tocool the temperature of combustion andreduce NOx emissions. The amount ofwater is between 80-100% of the fuelflow rate.

The DLN/DLE combustors have multiplefuel nozzles in each combustor chamber,One center pilot fuel nozzle and from 5-8secondary fuel nozzles in a circle aroundthe pilot nozzle. These nozzles are“staged” i.e. pilot nozzle is on all thetime, while the surrounding nozzles,which may be connected in two or threegroups of fuel nozzles, come on and offat various speeds during start-up. Thefuel is pre-mixed in the fuel nozzlesbefore it enters the combustor linerwhere combustion occurs. The DLN/DLEcombustors have stability problems andare very susceptible to any liquids in the

fuel gas system, which lead to aphenomenon known as flashback.Flash back is caused by thecombustion flame moving from theprimary combustion zone on to thefuel nozzles, causing a melt downof the fuel nozzles as shown inFigure 8.

Figure 8

Combustor Nozzles Burnt due to FlashBack Problems in a DLN Combustor

Can-Annular type combustors and thesmall side combustors can be easilyremoved without removing the casingand the combustion liners and nozzlesare easily inspected for cracks andburned areas without having to removethe turbine casing. Silo Combustors canalso be easily examined after they havecooled and technicians can enter thecombustors to examine the combustortiles. The best way to examine theannular combustors is with the use ofborescopes.

Short, individual cracks especially indiffusion combustors are not uncommonand need no immediate attention.However, if the cracks are grouped suchthat their continuance or the beginningof another crack could cause the loss ofa piece of metal, then a repair should bemade. Cracks of this nature normallycan be welded with a type of welding rodrecommended by the manufacturer,depending on the kind of metal involved.Burned or warped areas in combustionchambers or baskets can be cut out andnew sections welded. However, burnedareas should be studied with regard tolocation, pattern, or repetition in allchambers to determine the cause of theburning.

TURBINE MAINTENANCE

37

Table 4 indicates the various foulingmechanisms that affect the combustorsection of the Gas Turbine. The tableindicates the effect that various typesof fouling mechanisms have on theentire combustor section includingDiffusion and DLN combustors, fuelnozzles, cross-over-tubes, and thetransition pieces. The table deals withthe effects on can-annular and annularcombustors.

Table 4

Flash Back This is a phenomenon

common in DLN combustors, and isaccelerated if there is any liquids in thefuel gas No problem in diffusioncombustors Major problem in thesetype of combustors. Caused by flamebeing moved back to the fuel pre-mixnozzles which destroys these nozzles,also accompanied by High vibration andpulsation

Dual Fuel Liquid Fuel and naturalgas. Operation at various percentmixture settings. Good operation at allpercent mixture settings. Changes ofpercent on line possible On-linechange of fuel not possible. Unit has tobe shutdown and new fuel nozzles mustbe inserted.

Individual burned areas may indicate adirty or faulty fuel burner nozzle ormisalignment of the combustionchamber. Similar burned areas invarious chambers may indicateabnormally high firing temperaturesduring starting due to excessive fueluse. They may also be the result of"slugs" of liquids entering with the fuelgas, excessively rapid starts, oroverloading of the turbine. In the caseof DLN combustors problems with “flashbacks” due to liquids in the fuel gasdestroy the fuel pre-mix nozzles.

The combustion chamber positions aswell as the actual chambers or basketsshould be permanently numbered, and acomplete record should be made foreach basket regarding hours of service,

repairs, or replacements made, andtheir location in the turbine at eachinspection date. The basket ends or atplaces where they are supported shouldbe inspected for excessive wear fromvibration or expansion and contractionmovement. Repair of these parts shouldbe made by cutting out and welding innew materials or replacing spring seals ifnecessary.

The Combustor Cans are connected tothe “Transition Piece” which thenconnects to the turbine casing. TheTransition pieces are exposed to the

highest temperatures in the gasturbines. The transition piecesshould be inspected for crackingand wear at points of contact.Transition pieces are now beingcoated with a TBC. Wearusually occurs between thetransition piece and thecombustion liner sleeve, andalso at the first-stage nozzle fit.The cylindrical section of thetransition piece may bereplaced if the wear isexcessive; wear at the nozzle-end of the transition piece ismore serious because it allowsexcessive vibration of thetransition piece, which mightlead to cracking. Transition

pieces should be replaced if 50% of theinner or outer seal is reduced to half theoriginal thickness. If the transitionpiece is in otherwise excellentcondition, the seals may be ground offand replaced. Floating seals which jointhe transition piece to the turbinecasing near the first stage nozzle vanesshould be examined closely. Transitionpieces should be replaced if cracks arefound in the body. It is highlyrecommended that the combustor linersand the transition pieces be lined with athermal barrier coating, so as to reducethe metal temperatures.

Turbine Section

The gas turbine consists of three to fivestages, each stage consists of a circularrow of nozzle vanes followed by a row ofturbine blades. The first two row ofturbine blades usually are non-shrouded,while the last few stages where theblades are long are also shrouded asseen in Figure 9. In this figure the firsttwo rows have Thermal Barrier Coating(TBC). These coatings for each mil ofcoating thickness reduces the metaltemperature by about 14 ºF (8 ºC).

Figure 9

A Typical Gas Turbine’s Axial FlowTurbine Section

The first-stage turbine nozzle vanes canbe superficially inspected by the use ofa borescope for bowing by entering the

turbine through the combustionchamber areas or by removinginspection plates. In certain turbines(and by somewhat difficultmaneuvering) the last row of turbinerotating blades can be inspected byentering through the turbine dischargeduct. The opportunity should be takento measure, if possible, the blade tipclearance at eight points on thecircumference. Comparison of theseclearance readings with those atinstallation or at some previous timewill indicate if rubs have occurred andwhether or not the casing seal ring iswarped and out of round. It will alsoindicate whether or not the rotor isbelow its original position and requiresfurther investigation at the overhaulperiod.

As the hot sections become exposed,preliminary inspection for cracks orbowings should be undertaken toestimate work to be done. Cracks areusually noted at the trailing edge of theblades at around 1/3 the blade heightfrom the blade platform. The hightemperature in the new blades havecaused major failures at the bladeplatforms and due to leakages of thehigh temperature air the labyrinth sealsor the honeycomb seals have had majorblade failures.

Incomplete combustion or excess fuel During start-up the fuel is notcombusted and collects in thestationary vanes, which act as flameholders. Ensure that the control systemhas a rate of acceleration shutdownmode

Hot Corrosion Type I (over 1500ºF) Rapid form of oxidation, caused bythe reaction of Na in the air or fluid,sulfur which is usually in the fluid, andoxygen. Intergranular attack, sulfideparticles and a denuded zone of basemetal.

TURBINE MAINTENANCE

38

Hot Corrosion Type II ( between 1100ºF-1450ºF) Caused by low melting eutecticcompounds resulting from thecontamination of sodium sulfate andsome of the alloy constituents such asnickel and cobalt. Layered type ofcorrosion scale

Hot Gas Erosion Oxidation Caused bysmall solids in the air or the fuel. Bypoor combustor pattern, excessive EGTpattern

Blade Tip Rubs Due to very small tipclearance, and high metal temperaturesin the blades

Blade Fretting Erosion Fretting in thedove tails/ fir trees is caused by therocking action of the blades. Peakingturbines are highly susceptible to thisproblem

Blade and wheel Rupture Failure Thisfailure occurs in high temperature andhighly loaded blades (highly stressed)and disks. Disk failure can becatastrophic. Caused by inadequatecooling due to blockage of coolingpassages.

Foreign Object Damage / DomesticObject Damage FOD occurs frommaterials coming from an externalsource to the gas turbine, and DODoccurs from failure of internalcomponents.

Low Cycle Fatigue (LCF) Turbine disks,and first stage turbine suffering from lowsteady state stress, also due to thermo-mechanical fatigue problems. Peakingturbines more susceptible.

High Cycle Fatigue Can occur in anyblades or vanes due to blade resonancefrequency being excited. This usuallyoccurs in blades where there are no tipor mid-span shrouds.

Turbine blades should be closelyinspected for erosion and cracks. Themost critical areas in the turbine rotorare the fir-tree section, where theblades are attached to the rotor, and thetrailing edge of the blade near the hub.The trailing edge of the turbine blade isusually the hottest section of the blade,and cracks usually start at the trailingedge at about 1/3 the height of theblade from the base. These areas shouldbe carefully cleaned and checked forcracks with spray penetrant.

The coatings should be stripped. Theyshould then be inspected minutely forcracks by means of red dye or blacklight. The first-stage nozzle vanes willprobably need attention, which can bedone on the job. In older design vanesbowing on the trailing edge, if any, canbe taken out by inserting a spacer pieceof correct cross-sectional area betweenthe vanes, heating the top vane to red

heat with a torch, and forging the vaneedge flat with a hammer and flatter.The cracks, if less than 1.5 inches long,can be grooved out and welded,providing the crack does not run underthe end-supporting rings. In this casethe vane must be removed and welded ora new vane fitted in place. As the vanesare welded, they must be continuallychecked for new cracks, which in turnmust be grooved and welded andchecked again.

The new advanced nozzle vanes havethousands of cooling holes through outthe vanes. These vanes have the hottestsection at the leading and trailing edgesof the vanes. Figure 10 shows a newdesign nozzle vane with a burnt leadingedge and a burnt trailing edge. Thesevanes due to the very high temperatureof over 2400ºF (1316 ºC) also requirecooling of the nozzle platforms.

A. Leading Edge Vane

B. Trailing Edge Vane

The new advanced nozzle blades,because of their single crystal structure,or directionally solidified vane structure,and very complex cooling sections cannot be repaired. The older alloy blades(IN 738) can be rejuvenated. Beforerejuvenation the blades must beinspected for damage. There are twodistinct types of damage can berecognized: surface damage and internaldegradation. Surface damage may bedue to either mechanical impact orcorrosion and is generally confined to theblade airfoil. In both cases light damagecan be removed by blending or dressing,and then applying coating for surfacesmoothness and temperature protection.Blending of the trailing edges andleading edges should not leave the chordat the blade tip less than 75% of theoriginal blade chord length. Blades withsevere surface damage or cracks usuallyare scrapped.

When properly applied, these coatingscan increase the life of the bladesconsiderably, in some cases even morethan when they were new. Advances inhigh temperature coatings for severe hotcorrosion service have resulted in thelow unit cost feature of packcementation and the economy ofelectroplating to yield multiple elementcoatings containing precious metalaluminides. These coatings are availablein several combinations of platinum,rhodium, and aluminum for applicationto cobalt and nickel based vanes andblades. Most of the newer first twostages of blades are coated with TBCcoating. These coatings were optionalon the old turbines but they are nownecessary to maintain the blade metaltemperature below 1350ºF (732ºC).

Internal degradation is caused bymicrostructual changes, which resultfrom extended exposure at hightemperature under stress. Themicrostructural changes are responsiblefor the reduction in mechanicalproperties. Three forms of internaldegradation have been verified: (1)precipitate coarsening or overaging, (2)changes in grain boundary carbides, and(3) cavitation or void formation.

Normal reheat treatment can partiallyrestore blade properties; however, itdoes not appear to be capable of fullproperty recovery, although themiscrostructures are comparable to newblades. This shortcoming implies thatcavitation may be present and was notremoved by conventional reheattreatment. Hot isostatic pressure (HIP)processing is an alternative that ensuresvoid removal. It has demonstrated itsability to remove even gross internalshrinkage porosity in investmentcastings.

While repairing the older first-stagenozzle vanes, the upper and lower vanesection should be bolted or clampedtogether, and the entire ring should beplaced on a flat, level surface, orsufficiently supported in the horizontalplane to prevent heat warpage or bowingof the ring due to heating of the vanesduring their repair.

After straightening or taking out anybowing in the trailing edges of the vanes(partitions), perpendicular distancesbetween the trailing edges of each vaneand the surface of the next should becarefully measured. An average of thesedistances should be made and thencorrected to a plus or minus percentageapproved by the manufacturer. Thismethod will help to assure equaldistribution of gas flow to the first stagerotating blades for elimination of bladevibration.

Turbine rotating blades cannot be fieldrepaired if they are cracked. If one ortwo blades are damaged mechanically,the manufacturer may recommend fieldrepair or replacement of the damagedblades. However, if several blades arefatigue cracked, it is recommended thatthe entire set be replaced, since theremaining blades have been exposed tothe same operating conditions and,therefore, have little fatigue life left.

Dr. Meherwan P. Boyce, P. E., C.Eng.

FELLOW: ASME(USA), I.MechE(UK),IDGTE(UK)

THE BOYCE CONSULTANCY GROUP,LLC.

PHONE: 713-807-0888

FAX: 713-807-0088

TURBINE MAINTENANCE

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Working with ourpartners Hydrastore,Atos & MP Filtri we

offer not only a PreventativeMaintenance Service but ourexperienced engineers canoffer advice on improvementsto filtration, solutions tosystem overheating and moregeneral fault diagnosis.

A routine part of hydraulicservicing is to establish thecondition of the hydraulicfluid and its suitability forcontinued use.

This is done on-site, withoutinterrupting production, usingour Laser Particle Counter.

If necessary, more detailedanalysis can be carried outfrom samples taken.

To complement our servicewe carry large stocks ofreplacement hydrauliccomponents, including valves,pumps and filters.

Our extensive workshops areequipped for all types ofhydraulic repairs including

repair or complete re-manufacture for hydraulicand pneumatic cylinders.

Allison Hydraulics LtdUnit 2 Factory LaneOff Rooley LaneDudley HillBradfordBD4 9NWTel 01274 687327

Allison Hydraulics Ltd13B Harvey CloseCrowther Ind Estate District 3WashingtonTyne & WearNE38 0ABTel 0191 416 1260Email:[email protected] visit:

www.allisonhydraulics.com

Allison Hydraulics has provided aservice to UK Industry for over 30years, starting from its base in theLeeds/Bradford area and laterexpanding with another servicefacility in Washington Tyne & Wear.

HydraulicServicing

42

True-RMS clamp meter measuresdown to 1mA with no circuitdisturbance.

GMC-I PROSyS has introduced the CP41

AC/DC True RMS Clamp Meter, , a hand-

held unit that combines simplicity of

operation and convenience with non-

invasive measurement of current to an

accuracy of ± 1% of reading and

resolution of 1mA.

Measurement capability in the mA range

permits verification of 4-20mA current-

loops in process-control systems, while

the meter is equally applicable to testing

light-industrial and residential electrical

installations. The CP41 measures,

selectably, DC or AC currents with a

resolution of 1mA and, on its AC ranges,

with true-RMS current indication.

It maintains accuracy even in electrically

noisy environments, featuring excellent

rejection of external magnetic fields

together with a very high level of

immunity to interference from voltage

transients. The meter is battery-

powered, and has a 4-digit liquid-crystal

display: full-scale readings are up to 4A

or 40A, with auto-ranging and auto-zero

functions. GMC-I PROSyS also offers a

second variant of the CP41, the CP410,

which measures higher currents: its auto-

range full-scale limits are up to 40A or

400A. The GMC-I PROSyS CP41 uses

compensated Hall-Effect sensing in a

patented magnetic circuit, to detect the

magnetic current generated by the

current of interest; this technology

allows measurement of both DC and AC

currents. AC currents are measured over

a frequency range of 15 to 400 Hz.

In operation, the user opens the jaws of

the probe, which have a 25-mm

aperture, and closes them around the

conductor carrying the current of

interest: advanced design of the

magnetic circuit means that location of

the conductor within the aperture is non-

critical and errors due to off-centre

positioning are negligible. The CP41’s

design supports safe, single-handed

operation in hazardous areas, assisted by

a display-hold function which allows the

user to take a measurement in a

difficult-to-reach location, remove the

CP41 from the test site, and to bring it

back into clear view still displaying its

current reading.

The CP41 and CP410 meet the Safety

requirements of EN61010-2-032:2002 and

the EMC specifications of EN 61326-2-

2:2006, and provide safe operation on

uninsulated conductors carrying voltage

of up to 300V with respect to ground.

They measure 194 x 74 x 25mm, weigh

235g, and operate for 15 hours from a

standard 9V alkaline battery.

About GMC-I PROSySGMC-I PROSyS designs, develops andmanufactures current probes, clampmeters, handheld instruments andsystems for current and voltagemeasurement, as well as measurementand processing of electrical parameters.

For more information visit: www.i-prosys.com.

For further information, pleasecontact:

Ahmet Selcuk, GMC-I PROSySTel: +44 1695 [email protected]

Do notdisturb!

Key points:· AC and DCmeasurements with 1mAaccuracy/resolution· Non-invasive currentmeasurement – no needto break connections· Full accuracymaintained in harshelectrical environments· Lightweight, single-handed operation

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With the Health & Safe-

ty Executive about to

commence on-site

inspections of hand-

fed platen presses, users of this high-

risk machinery need to ensure that

their presses meet the required safety

standards. By working closely togeth-

er, two companies have developed a

novel, high integrity safety solution

for a hand-fed platen press, which us-

es an array of light beam sensors and

a modular safety control and monitor-

ing system.

A collaborative development project be-

tween two UK-based companies has re-

sulted in a much safer working

environment for operators of a hand-fed

platen (die cutting) press.

In November 2009, machinery safety spe-

cialist Pilz Automation Technology and

SCA Display UK, a manufacturer of Point-

of-Display (POD) products for retail cus-

tomers, began working together to im-

prove the safety of a hand-fed platen

press at SCA Display’s production plant in

Shenstone.

Part of SCA, SCA Display UK’s Shenstone

plant employs around 80 staff and manu-

factures a wide variety of point-of-sale

and POD products, mostly custom de-

signed products made from cardboard.

The factory uses a wide range of machin-

ery, including digital and silkscreen

printers, die cutters, folding & gluing

machines and platen presses. Most of the

Pilz Automation Technologyand SCA Display UK co-developinnovative safety solution forhand-fed platen press

45

die cutting uses semi-automatic presses,

but one of the presses is hand-fed, which

is used for short runs and one-off cus-

tomer specials.

Ian Clews, Facilities Manager at Shen-

stone, has been working with platen

presses for more than 30 years and SCA

are members of the Confederation of

Paper Industries, where machinery safe-

ty is high on the agenda. “Quite frankly,

the use of these machines has been a

concern for many years, particularly in

the dwell mode. With two fatalities in

the UK in recent years, users of these

machines need to review their safety

systems.”

“A typical hand fed platen press closes

with a tremendous force, often with the

operator’s body in close proximity. This

means that operator safety is extremely

critical. At Shenstone we have a continu-

al improvement policy which instigated

further upgrades to our platen press to

ensure that additional operator safety

measures.”

HSE Safety Alerts and Inspections

Ian Clews is not alone in his views on

the need to improve the safety of

hand-fed platen presses. In the UK, the

Health & Safety Executive (HSE) has

recently issued safety alerts to users of

hand-fed platen presses. It is estimated

that in the UK alone, there are be-

tween 1,000 and 2,000 such presses

that require safety upgrades, mostly

operated by companies in the printing

and packaging industries. Most of the

high-risk machines fall into the 1.4m to

2m-width range.

The HSE is currently considering issuing

alerts to users in order to raise aware-

ness of the potential dangers of whole

body access between the platens of

these machines when operating in the

‘dwell’ mode. The alerts are in re-

sponse to two fatalities since 2008 in

the UK, where operators were crushed

between the platens as they intervened

during normal production. In both cases,

the hand-fed machine was being used in

the dwell mode and the power to the

platen was not isolated before the inter-

vention occurred and so the safety de-

vices fitted to the machine did not

prevent the platens closing on the oper-

ator.

“During the setting process, waste re-

moval, replacement of lay stops or mis-

feed retrieval, even with the most safe-

ty conscious operators may try to beat

the dwell and climb onto the platen

press bed or lean into the machine.

Whilst between the fixed and moving

platen beds the operator is not detected

by any of the usual safety systems,” ex-

plains Ian Clews.

According to the HSE, the latest hand-

fed platen presses are much larger than

their predecessors and many users now

use the machine’s dwell mode to either

give them more production flexibility or

to speed up the machine’s output, as

this mode can often double the speed of

46

operation. On most hand-fed platen

presses, climbing onto the platen from

the normal operating position in front of

the machine can be done without operat-

ing the safe edge that is normally fitted

to the leading edge of the lower platen.

This means that if a safe system of work

is not followed, including isolating the

machine, the platen may then continue

to cycle if it is being used in the dwell

mode and the protective devices will not

automatically be triggered.

Further investigation by the HSE has

showed that standards of guarding and

working practices on many existing, larg-

er hand-fed platen presses need to be

improved significantly. HSE has an-

nounced that it will commence on-site

inspections of hand-fed platen presses in

October 2010.

In his presentation to a group of machin-

ery safety suppliers at the HSE’s Birming-

ham offices on 12th July 2010, Tim Small,

HM Principal Inspector at the HSE, stat-

ed: “The HSE deems hand-fed platen

presses as high risk machines. Enforce-

ment action will be taken against any UK

firms that aren’t taking appropriate ac-

tion to meet these new safety expecta-

tions.”

Employee Safety-Driven Approach

In November 2009, SCA Display UK decid-

ed to improve the safety of its hand-fed

platen press at Shenstone to better pro-

tect employees. Ian Clews contacted Pilz

Automation Technology to discuss possi-

ble safety solutions.

“By this time, I had already devised sev-

eral concepts for upgrading the safety of

the platen press, but needed to talk to a

machinery safety specialist supplier such

as Pilz about how the solution could be

realised from a technological viewpoint.

I also wanted the solution to be modular,

enabling a best option for employee pro-

tection rather than a cost option. It was

critical that we worked with a supplier

that had in-depth knowledge of current

machinery safety legislation and stand-

ards, but with the ability to then apply

that knowledge to developing the most

appropriate safety system for our ma-

chine,” says Ian Clews.

Chris Sloan (Area Sales Engineer) and

Stewart Robinson (Consultant Engineer)

at Pilz Automation Technology have

worked closely with Ian Clews on the

platen press project since early 2010.

Chris Sloan says: “Initially we visited

Shenstone to assess and analyse the plat-

en press and to discuss safety issues and

potential solutions. SCA wanted a work-

ing solution based on a modular safety

platform that would include all the nec-

essary hardware and software, tailored

to suit the machine.”

Stewart Robinson adds: “One of Ian

Clews’ favoured concepts was to use an

array of light beam sensors that would

monitor the side and platens in order to

detect any violation of the machine’s

danger zone whilst the press was closing.

As far as we are aware, the solution

we’ve developed is the only one of its

kind in the UK, where light beam sensors

are being used to monitor the area di-

rectly above the moving platen.”

The overall safety solution is based on

Pilz’s PNOZmulti modular safety system.

PNOZmulti is multifunctional, freely con-

figurable and is ideal for monitoring

safety functions such as Emergency-Stop,

safety gates and light barriers, as well as

performing standard control functions.

Rather than hard wiring, safety circuits

can be generated on a PC using

PNOZmulti’s intuitive configuration soft-

ware. This configuration can then be

stored on a memory card and download-

ed to the PNOZmulti base unit.

The solution incorporates a PNOZmulti

base unit, with input and output expan-

sion modules to control all aspects of

machine safety and control. “We wrote a

functional specification for the press,

then engineered a solution based on

these functional safety requirements. We

supplied all the hardware, including the

light beam array and safety controller, as

well as writing all the software code for

the application,” states Stewart Robin-

son.

47

The hand-fed platen press at Shenstone

is fitted with a number of general pur-

pose safety devices such as trip bars,

interlocked guards, right and left hand

emergency stops, safety mat, front safe

edge, lumbar bar, safety gate key

switch, left and right side light curtain.

All these devices have the same func-

tional safety requirements, which are to

prevent all hazardous movement by en-

suring that the clutch safety valve is

de-energised and that the main motor is

stopped, and to prevent unintended

restart. The target safety integrity level

for each General Safety Function is SIL 3

(EN 62061), equivalent to PLe according

to EN ISO 13849-1.

SCA’s Safety Solution

The machine now uses an array of

PSENop4S light beams supplied by Pilz.

As Ian Clews explains: “We did have a

few teething problems based around

alignment of the sensors, but this was

down to the original machine mount-

ings, which were not robust enough to

provide a solid foundation for the light

beam sensors.

We quickly resolved this issue by devel-

oping more robust bearing mountings,

which enable the sensors to be adjust-

ed more easily. We also developed an

infra-red sighting device that simplifies

the alignment of the sensors.”

The light beam array now detects a

violation of the danger zone whilst the

press is closing. This is achieved by se-

quentially muting the laser beams as

the press closes.

If any beam is broken before it has

been muted, the press clutch safety

valve is de-energised immediately

bringing the hazardous movement to a

stop. Once the final beam has been

broken (press closed) the beams re-

main muted until the press cam switch

has operated, signalling that the press

is at the ‘home’ position.

The muting points are derived from the

simulation of press position carried out

within the PNOZmulti control system.

The application also includes checking

that the press cam switch operates cor-

rectly in each press cycle.

It should be remembered that this solu-

tion must be accompanied with robust,

safe systems of work, training, regular

maintenance and risk assessments.

“The services provided by Pilz were ex-

ceptionally good and I cannot fault them

at all. Any modifications or software up-

dates were carried out quickly as and

when required and technical support

from Pilz engineers was excellent.

The working relationship was very close

and has resulted in a truly collaborative

solution. The project itself was complet-

ed successfully on the 16th of July and

the press was handed over to our pro-

duction team two weeks later,” Ian

Clews concludes.

Please email [email protected] for

more information about the project or

telephone 01536 460766 or visit

www.pilz.co.uk

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