beddynamically. Two laser scannersat
bothendsof the train constantlysense
the tunnel profile. Thesystem controller
analyses the informationabout the
contoursof thenext 20-metresection in
fractionsof asecondand forwards the
control pulses to the individual suction
nozzles. Themoving cleaningunits there-
fore remain closeenough to the tunnel
walls toeffectively removedirt at all times.
If the laser scannersdetect obstacles
suchassignsor electronic switchboxes,
the tunnel cleaning trainsimply retracts
the respectivesuctionarmsat the right
time. Thisgigantic cleaningsystem isop-
eratedby just twopeople–a locomotive
driver and themachineoperator. Thanks
tovideo camerasandeightmonitorsper
driver’s cab, they constantlykeepaneye
on themost important areasof their
machine. Dependingon the typeof appli
cation, there is room for up toseven
people ineachof the twodriver’s cabs.
Servopneumatics for increasedsafety
Thequickandsafemovement of the
suctionnozzlesandsuction feet is the
workof the latest servopneumatics from
Festo. Thehydraulic solutionsusedby
Schörling in thepast havebeen replaced
bypneumatics for theveryfirst time in the
latestmodel of the tunnel cleaning train.
“Servopneumaticsare just cleaner and
safer,”explainsprojectmanagerDaniel
Eberhardt. “There isnocontaminationdue
topossible leaks in thehydraulicsystems.”
Thescopeof the Festo componentsused
extends fromair preparationwith two
serviceunit combinationsMSB6 right up
to16standard cylindersDNCI-63with in-
tegrateddisplacement encoder, including
16position controllersCPX-CMAXwhich
ensure that thesuctionnozzlesand feet
movequicklyandflexibly into their pro-
grammedpositions. Even large loadsare
acceleratedandbrakeddynamicallyand
precisely. 16proportional valvesof type
VPWPcontrol thesupplyandexhaust air
in the cylinders. TheCPXsystem is the
automationplatform, servingbothasan
electric terminal equippedwithcontrollers
CMAXandasavalve terminal equipped
withvalvesVTSA, for additional switching
functions in thesystem.
The laser scannersat eachendof the
tunnel cleaning trainaremovedbya rod-
less cylinderDGCI-40with integrated
displacement encoder andaproportional
valveVPWP-8. The fast, precise interaction
between cylinder andvalvesupportsopti-
mumpositioningof thescanners, allow-
ing them tosupplyaccuratedataabout
theexpected tunnel profile to thesystem
controller.
Small space, safeoperation
Inaddition tomaking theswitch fromhy-
draulics topneumatics, Schörlingdecided
touse theeasy-to-install andspace-savingdoublesub-baseVABP for thevery
first time. It replaces the individual com-
ponent solutions for variousemergency
stop functionsof servopneumaticaxes
thatwerepreviously required. “Installed
between thedriveandpower valve, the
VABPenablesdifferent switch-off func-
tions tobe realisedusingonesub-base:
stopping, exhausting, reversing left or
rightwith reducedspeedandpressure
compensation,”explainsDaniel Eberhardt,
describing thesafetyadvantageofVABP.
Comparedwithsolutions that have tobe
assembledusing individual components,
thedoublesub-baseVABPand theproven
switchingvalves from the ISOseriesVSVA
havemade itmucheasier for thecustomer
toevaluate thesystemasper theMachin-
eryDirectiveEN ISO13849-1and todeter-
mine thePerformanceLevel that canbe
achieved.
Co-operation fromdayone
The latestmodel of the tunnel cleaning
train fromSchörling incorporating the
innovativeservopneumatic solution from
Festo isalreadybeingused inBeijing’s
underground rail system. Itsnetwork is
around460km long,making it thebiggest
in theworld. ProjectmanagerDaniel
Eberhardt recalls thedesignprocessas
beingparticularlychallenging. Theprocess
from initial discussionswith theunder-
ground rail operators inChina to comple-
tionof the tunnel cleaning train took just
sevenmonths. “For us, itwashugely
important thatwehadapartner likeFesto,
onwhomwe could rely completely,”says
Daniel Eberhardt. The changeover from
hydraulics toservopneumaticswasa
totallynewdeparture forusandwehad to
placeour trust in the innovativesolution
andexpertiseprovidedby Festo.
Onlya fewmonthsafter both companies
met atHannoverMesse2012, aprototype
for theservopneumaticswasdeveloped.
Thiswas thenused toproduce thefinal
product. Service technicians from Festo
deliveredand commissioned theentire
servopneumatic system formovingand
controlling thesuctionnozzles. Inadd
ition to fast deliveryof the technological
hardware, theworldwideserviceprovided
by Festowasamajor sellingpoint for
Schörling. Formaintenanceandservice
work, Schörling canquicklyaccess the
Festoexpertiseavailableworldwide. This
ensuresa cleanenvironment for people
andmachines in the tunnelsof under-
ground rail networksall over theworld.
(A)Maximum impact inasmall space:
Valve terminalVTSAsavesspace thanks
to its compact design.
(B) Cleanliness for a longer service life:
Serviceunit combinationMSB6ensures
that thepneumatic components continue
to runsmoothly for a long time.
(C)Quick, safe, clean:
The cleaningunit
with itsmovablesuctionnozzlesand
suction feet has three fans ineach train
half, eachwithsuctionof 6m³/s.
(D)A total of 16standard cylinders
DNCI-63with integrateddisplacement
encoder position thesuctionnozzles
and feet quicklyandaccurately.
SchörlingKommunal
GmbH
GöttingerHof 9
30453Hannover
Germany
Areaof business:
Development and construction
ofmetro tunnel cleaning trains
“Installedbetween thedriveand
power valve, thedoublesub-base
VABPallowsdifferent switch-off
functions tobe realised.”
Daniel Eberhardt, ProjectManager SchörlingKommunal GmbH
(A)
(B)
(C)
(D)
1.2014
trends inautomation
Synergies
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