AU2020223635B2 - Amelioration of the Effects of Conveyor Belt Wander - Google Patents

Abstract

#$%^&*AU2020223635B220250710.pdf##### ABSTRACT A method of, and apparatus for, increasing the accuracy of conveyor belt measurements taken whilst the belt is moving by ameliorating the effects of belt wander, is disclosed. The method includes the steps of: 5 mounting at least one belt sensor (41-43) on a belt sensor mount (21-23) movable transversely to the direction of motion of the belt (11), providing a motor (31-33) to move the belt sensor mount in response to a belt wander signal indicating a direction and approximate magnitude of the belt wander, 10 simultaneously sensing the current location of each edge (A, B) of the moving belt using at least one pair of edge sensors (17, 18) located at the same downstream belt locations but on opposite edges of the belt, and generating the belt wander signal if the pair of edge sensors indicate the belt edges are both moving in the same direction and by approximately the same 15 magnitude. 5004T-AU 9 ABSTRACT A method of, and apparatus for, increasing the accuracy of conveyor belt 2020223635 24 2020 measurements taken whilst the belt is moving by ameliorating the effects of Aug belt wander, is disclosed. The method includes the steps of: 5 mounting at least one belt sensor (41-43) on a belt sensor mount (21-23) movable transversely to the direction of motion of the belt (11), providing a motor (31-33) to move the belt sensor mount in response to a belt wander signal indicating a direction and approximate magnitude of the belt wander, 10 simultaneously sensing the current location of each edge (A, B) of the moving belt using at least one pair of edge sensors (17, 18) located at the same downstream belt locations but on opposite edges of the belt, and generating the belt wander signal if the pair of edge sensors indicate the belt edges are both moving in the same direction and by approximately the same 15 magnitude. 5004T-AU 9 20 20 22 36 35 2 4 A ug 2 02 02020223635 24 Aug 2020 31 32 33 21 22 15 23 K 41 43 42A 42B 17 18 Il 3/5 FIG. 3

Description

3/5 24 Aug 2020 2020223635 24 Aug 2020

23 18

33

43 FIG. 3 2020223635

15

Il 22

K 42B

32

42A

21

31

41

Amelioration ofthe the Effects Effects of of Conveyor 2020223635 24 Aug 2020

Amelioration of BeltWander Conveyor Belt Wander

Field ofofthe Field theInvention Invention Thepresent The presentinvention invention relates relates to steel to steel cordcord conveyor conveyor belts. belts. 5 5

Background Art Background Art Such conveyorbelts Such conveyor beltsare arewidely widelyused used in in mining mining andand industry industry and and consist consist of aoftension a tension member(steel member (steelcords) cords)and anda atop top(carry) (carry) cover cover and andaa bottom bottom(pulley) (pulley)cover. cover. The Thecovers, covers, whichare which aregenerally generallymade made from from an elastomeric an elastomeric material material such such as rubber, as rubber, suffer suffer wear wear 10 during 10 duringservice serviceinin much muchthe thesame sameway way as as a motorvehicle a motor vehicletyre tyre wears. wears. Normally Normally the the carry cover carry coverwears wears more more than than the pulley the pulley cover cover if if the material the material conveyed conveyed is is abrasive. abrasive.

Wearininthe Wear the carry carry cover cover of ofaa running runningconveyor conveyorbelt beltisis not not uniform uniformacross acrossthe thewidth widthofof belt. In belt. general, the In general, thewear wearis is restricted restricted to to three three locations locations spaced spaced transversely transversely across across the the 15 belt. belt. TheThe central central wear wear location location is the is the resultofof result interactionbetween interaction betweenthethe product product being being

conveyedand conveyed andthethebelt beltcover coverandand thus thus is is typicallytowards typically towardsthethe centre centre of of thethe belt,but belt, but maybebelocated may locatedmore more to to one one sideside or the or the other other depending depending upon upon the the product product loading loading

conditions. conditions.

20 The The 20 other other two two locations locations arise arise because because of the of the curtain curtain like like "skirts"fitted "skirts" fitted to to the the conveyor conveyor

structure at structure at the the load load point pointononopposite opposite sides sides of the of the loadload point. point. TheseThese skirtsskirts are are intended to intended to prevent prevent the the loaded loadedmaterial materialinadvertently inadvertentlyleaving leavingeither eitherside sideofofthe thebelt belt and are and are also also intended to prevent intended to prevent the the spread spread of of dust. dust. The skirts are The skirts are rubber rubber flaps flaps which which

contact the contact the carry carry cover cover surface surface of of the the belt beltwhich which has has aa troughed troughed or or U-shaped U-shaped 25 configuration. 25 configuration. Because Because of this of this contact contact there there is expected is expected to be to be some some wear wear at these at these two two locationsbut locations butthis thiswear wear should should not not be excessive. be excessive.

However, However, itit is is possible for for some some of the the loaded loaded material material to tobecome trapped between become trapped betweenthe the lower edge lower edgeofofaaskirt skirt and and the the carry carry cover coverofofthe the belt. belt. In In this this case case wear can suddenly wear can suddenly 30 become 30 become accelerated, accelerated, oftenoften producing producing a deep aand deep and groove. narrow narrow Belt groove. Belt operators operators are are desirable of desirable of being able to being able to detect detect the the presence of such presence of such accelerated accelerated wear wearasasquickly quicklyasas possibleininorder possible orderforforrectification rectification action action to taken. to be be taken. If such If such action action is notistaken not taken the the belt belt life may life may be be prematurely shortened. prematurely shortened.

5004T-AU 5004T-AU 1

Australian Patent Patent No 2012 216 216 769 769(Belt (BeltWatch WatchAttorney Attorney RefRef 5004K-AU) and 2020223635 24 2020

Australian No 2012 5004K-AU) and

Australian Patent Australian Patent NoNo2012 2012 321 321 080 (Baseline 080 (Baseline Asset Technologies) Asset Technologies) both both disclose disclose essentially the essentially thesame same method method ofofmeasuring measuringthethethickness thicknessofofthe thecover coverremaining remaining on on thethe Aug belt. In belt. In this this way, wearcaused way, wear caused by skirts by skirts candetected can be be detected and measured. and measured.

5 5

Not every Not every belt belt wanders, wanders, but but for for those those that that do do wander, such measurements wander, such measurementsarearerendered rendered inaccurate by belt inaccurate by belt wander. wander.Generally Generallyspeaking, speaking, beltwander belt wander is generated is generated by various by various

mechanisms.InInone mechanisms. onetype typeofofbelt beltwander, wander,a abelt belt moving movingat,at,5-10 5-10meters metersper persecond, second,for for example, may example, maymove move sideways sideways at aatspeed a speed in the in the vicinityofof1mm/second vicinity 1mm/second - 1mm/minute - 1mm/minute

10 10 in first in a a first direction,andand direction, then then movemove in opposite in the the opposite direction. direction. Suchwander Such belt belt wander is is relatively slow. relatively slow.

Asecond A second type type of belt of belt wander wander is essentially is essentially permanent permanent for aofperiod for a period of the the belt's belt's life. life.

15 15 Remaining Remaining covercover thickness, thickness, or cover or cover wear,wear, is the is not not only the only conveyor conveyor belt belt measurement measurement

whichisis adversely which adversely affected affected by bybelt belt wander. wander.ItIt isis therefore therefore desirable desirable that that belt belt wander wander

be able be able to to bebetaken takeninto intoaccount accountduring during thethe measurement measurement of conveyor of conveyor belt belt characteristics and characteristics andthis thisisisthe theGenesis Genesis of the of the present present invention. invention.

20 Whilst 20 Whilst it generally it is is generally not not economically economically practical practical to provide to provide closely closely spacedspaced sensorssensors

transversely located transversely located across across the the entire entire belt, belt, even if this even if this is is done, done, without taking belt without taking belt wanderinto wander into account, account, erroneous erroneousresults results may maybebeobtained. obtained.

25 Summary 25 Summary of the of the Invention Invention

In accordance In accordance with with a first a first aspect aspect of the of the present present invention invention there there is is disclosed disclosed a methoda method of increasing of increasing the the accuracy accuracy of conveyor belt measurements conveyor belt takenwhilst measurements taken whilstthe thebelt belt is is movingbybyameliorating moving amelioratingthe theeffects effects of of belt belt wander, said method wander, said methodcomprising comprisingthethesteps steps of: of:

30 mounting 30 mounting at least at least one one beltbelt sensor sensor on on a belt a belt sensormount sensor mount movable movable transversely transversely to to the the direction ofofmotion direction motionof of thethe belt, belt,

providing aa motor providing motorto to move movesaid saidbelt belt sensor sensor mount mountininresponse responsetotoa abelt belt wander wandersignal signal indicating indicating aa direction directionand and approximate magnitudeofofthe approximate magnitude thebelt belt wander, wander,

5004T-AU 5004T-AU 2

2020223635 24 2020

simultaneously sensing simultaneously sensing the current the current location location of eachofedge eachof edge of thebelt the moving moving belt using at using at

least one least pairofofedge one pair edgesensors sensors located located at the at the same same downstream downstream belt locations belt locations but on but on oppositeedges opposite edgesof of thethe belt, belt, andand Aug generatingsaid generating saidbelt belt wander wander signal signal if said if said pair pair of edge of edge sensors sensors indicate indicate said said belt belt edges edges 55 are both are both moving in the moving in the same samedirection direction and andby byapproximately approximately thesame the same magnitude magnitude

In accordance In accordance with with a second a second aspect aspect of theof the present present invention invention there is there is disclosed disclosed an an apparatus for apparatus for increasing increasing the the accuracy accuracy of of conveyor belt measurements conveyor belt takenwhilst measurements taken whilstthe the belt is belt is moving moving by by ameliorating ameliorating the effects the effects ofwander, of belt belt wander, said apparatus said apparatus comprising: comprising:

10 10 at leastone at least onebelt beltsensor sensormounted mountedon on a belt a belt sensormount sensor mount movable movable transversely transversely to the to the

direction ofofmotion direction motionof of thethe belt, belt,

a motor a operatively connected motor operatively connected toto said said belt belt sensor sensor mount to move mount to movesame samein in response response toto

a belt a belt wander signal indicating wander signal indicating aa direction directionand andapproximate magnitudeofofthe approximate magnitude the belt belt wander, wander,

15 15 at leastone at least onepair pairofofedge edgesensors sensorslocated locatedatat the the same samedownstream downstream belt belt locationsbutbutonon locations

oppositeedges opposite edgesof of thethe belt belt andand arranged arranged to simultaneously to simultaneously sense thesense thelocation current currentoflocation of eachedge each edgeof of thethe belt,andand belt,

signal generating signal generatingmeans means to generate to generate saidwander said belt belt wander signal ifsignal if said said pair pair of edge of edge sensors indicate sensors indicate said said belt beltedges edgesare areboth bothmoving moving in the the same same direction direction and and by by

20 approximately 20 approximatelythe thesame samemagnitude. magnitude.

Preferablythe Preferably theatatleast leastone one belt belt sensor sensor senses senses a belt a belt property property selected selected from from the the class class consisting of remaining consisting cover thickness remaining cover thickness and and remaining remainingsteel steel cord cord volume. volume.

25 Preferably 25 Preferably the the edge edge sensors sensors are are ultrasonic. ultrasonic.

Preferablythe Preferably thecurrent current location location of each of each edge edge of theof the moving moving belt isrelative belt is sensed sensed to relative a to a stationaryframe. stationary frame.

30 Brief 30 Brief Description Description of the of the Drawings Drawings

A preferred A preferred embodiment embodiment of the of the invention invention will will nownow be described, be described, by of by way way of example example

only, with only, with reference reference to to the theaccompanying drawingsininwhich: accompanying drawings which: Fig. 11 is Fig. is aa schematic schematicplan plan view view of carry of the the carry cover cover of a prior of a prior art conveyor art conveyor belt, belt,

5004T-AU 5004T-AU 3

Fig. 22 is is aa schematic schematicplan 2020223635 24 2020

Fig. plan view view of conveyor of the the conveyor belt ofbelt Fig.of 1 Fig. 1 including including

measurementapparatus measurement apparatus in in accordance accordance with with an an embodiment embodiment ofpresent of the the present invention, invention,

Aug Fig. 33 is Fig. is aa schematic schematiccross-sectional cross-sectional viewview taken taken along along the linethe line111-111 III-III of Fig.of 2,Fig. 2, Fig. 44 is Fig. is aa schematic schematicremaining remaining belt belt covercover profile profile showing showing the belt the belt wear, andwear, and 55 is aa schematic Fig. 55 is Fig. schematiccircuit circuit diagram diagram the signal of signal of the generator. generator.

Detailed Description Detailed Description Asseen As seenininFig. Fig.1, 1,a aconveyor conveyor belt belt 11 ahas 11 has lefta edge left edge indicated indicated by the by the line linea A A and and right a right edgeindicated edge indicatedby by line line B. B. At the At the timetime of manufacture of manufacture these these lines lines were bothwere both originally originally 10 straight 10 straight andand essentiallyparallel. essentially parallel. However, However,over overtime timeedge edge defects13 13arearecaused defects caused andand

these can these canbebeupupto to 20 20 or or 100 100 meters meters in length in length andinvary and vary in but width, width, but are typically are typically in in the vicinity the vicinity ofof25mm 25mm in width. in width. It isItnot is not unknown unknown for the for theorfirst first last or last reinforcing reinforcing steel steel cord of cord of aa conveyor belt to conveyor belt to be be damaged orcompletely damaged or completelyremoved removedas as a resultofofananedge a result edge defect. defect.

15 15

The line The line C is aa line C is lineofofwear wearcreated createdby byconveyed conveyed product, product, for for example, becoming example, becoming

wedged wedged between between the conveyor the conveyor belt 11 belt and a11 andside left a left side skirt skirt (not (not illustrated). illustrated). It is theIt is the degreeofofwear degree wear along along the the line line C which C which is of interest is of interest to the to theoperator. belt belt operator.

20 However, 20 However, as indicated as indicated in Fig. in Fig. 1, the 1, the belt belt 1111 may may wander wander to the to the right right as as indicated indicated byby

dashed linesorormaymay dashed lines wander wander to thetoleft the asleft as indicated indicated by dot by dot dash dashAslines. lines. As explained explained

above, this above, this wander maybebetransient wander may transient or or permanent. permanent.

As seen As seen in in Figs. Figs. 22 and and 3, 3, aa crossbar crossbar 15 15isispermanently permanently mounted abovethe mounted above theconveyor conveyor 25 belt belt 25 11, preferably 11, preferably at a location at a location where where the belt the belt and is flat is flat and relatively relatively flap flap free. The free. The crossbar1515supports crossbar supports two two ultrasonic ultrasonic edge sensors edge sensors 17, 18. 17, 18. In addition, In addition, the 15 the crossbar crossbar 15 supports three supports three belt belt sensor sensor mountings 21, 22, mountings 21, 22, 23 each of which each of consists of which consists of aa rack rack and and

pinion style pinion style variable variable location locationdevice devicewhich which is is driven drivenby by aacorresponding corresponding stepping

motor31,31,32,32,33.33. motor TheThe rackrack of belt of the the belt sensor sensor mounting mounting 21 supports 21 supports a belt a belt sensor 41. sensor 41. 30 Similarly, 30 Similarly, thethe rack rack of of thethebelt beltsensor sensormounting mounting23 23 supports supports a beltsensor a belt sensor4343whilst whilstthe the rack ofofthe rack thebelt beltsensor sensor2222 supports supports a pair a pair of belt of belt sensors sensors 42A 42A and and 42B. In 42B. In the the present present embodiment, eachofof embodiment, each thebelt the belt sensors sensors 41, 41, 42A, 42A,42B 42Bandand 4343 is isa aremaining remainingcover cover thicknesssensor. thickness sensor.

5004T-AU 5004T-AU 4

The belt The belt sensor sensor mountings 21,22, mountings 21, 22, 23 23 are are each each able able to to be be covered by aa flexible covered by flexible bellows bellows

like cover like cover(not (notillustrated) illustrated)ininorder ordertotoprotect protect thethe mountings mountings from ingress from ingress of dust,of dust, etc. etc. In addition, In addition, each eachofof thebelt the belt sensors sensors 41-43 41-43 is preferably is preferably able able to to be raised be raised into a into a 55 standby standby position position and and lowered lowered intointo a measurement a measurement position, position, for example for example as disclosed as disclosed

in Australian in Australian Patent Patent Application Application No. 2016202 No. 2016 202263 263(Belt (BeltWatch Watch - Attorney - Attorney Reference Reference

5004N-AU) 5004N-AU) thethe contents contents of of which which areare hereby hereby incorporated incorporated into into thethe present present

specificationbybycross specification cross reference. reference.

10 10 Fig. Fig. 4 shows 4 shows a typical a typical remaining remaining belt belt cover cover profile profile with with thethe lineofofwear line wearC Cindicated. indicated.

Fig. 55 shows Fig. showsthat that thethe outputs outputs of the of the edgeedge sensors sensors 17, 18 17, are 18 are connected connected to a to a central central processing unit 45 processing unit whichoutputs 45 which outputsaa belt belt wander signal to wander signal to each of the stepping each of stepping motors motors

31, 32, 31, 32, 33 33sosoasastotosimultaneously simultaneously control control the position the position of the of thesensors belt belt sensors 41-43. A41-43. A 15 "Belt "Belt Wander Wander Signal" Signal" is only is only generated generated if both if both the the edgeedge sensors sensors 17, 17, 18 indicate 18 indicate that that

the belt the belt isismoving moving sideways in the sideways in the same direction and same direction and by by essentially essentially the the same same amount. amount.

In this In this way, thebelt way, the beltsensors sensors 41-43 41-43 canmade can be be made to the to track track the movement movement of the belt of 11 the belt 11 beneath them. beneath them. As Asa aconsequence, consequence,irrespective irrespectiveofofbelt belt wander, wander, the the belt belt sensors sensors 41-43 41-43

are continuously are continuously sensing sensing the same the same longitudinal longitudinal strip orstrip loopor of loop belt. of belt.

20 20

Preferably the Preferably the edge sensors 17, edge sensors 17, 18 18 are are sampled at aa 30 sampled at 30 Hz rate and Hz rate each sample and each sample creates an creates an individual individual window oftime window of timeduring duringwhich whichthe theinstantaneous instantaneousvalue valueofofthe the positionofofthe position theedge edge of of thethe belt belt is is measured measured in millimetres in millimetres relative relative to the to the crossbar crossbar 15. 15. This spatial This spatial data data isisthen thenprocessed processedby bythe theCPU 45 and CPU 45 and the the Belt Wander Signal Wander Signal

25 generated, 25 generated, if necessary. if necessary.

The foregoing The foregoingdescribes describesonly onlyone oneembodiment embodiment of the of the present present invention invention andand

modifications, obvious modifications, obvious to those to those skilled skilled inconveyor in the the conveyor beltcan belt arts, arts, can be be made made thereto thereto

without departing without departing from fromthe the scope scopeof ofthe the present present invention. invention. For example, other example, other

30 characteristics 30 characteristicsof of theconveyor the conveyor belttotobebemeasured belt measured include include thethe volume volume of steel of steel

remainingin in remaining thethe steel steel cords, cords, and and the the like.like.

5004T-AU 5004T-AU 5 addition, itit is In addition, is possible to have haveonly only a single motor and aand a single longonrack whichon which 2020223635 24 2020

In possible to a single motor single long rack

all the all the belt belt sensors 41-43areare sensors 41-43 mounted. mounted. Alternatively, Alternatively, rather rather than utilise than utilise the the above above

Aug describedrack described rack andand pinion pinion arrangement, arrangement, it is possible it is possible to use to use a"lathe a short short bed" "lathe bed" device device withits with its movement movement being being controlled controlled by a linear by a linear actuatoractuator rather rather than than a motor. a stepping stepping motor. 5 5

The term The term"comprising" "comprising"(and (anditsitsgrammatical grammaticalvariations) variations)asasused usedherein hereinisis used used in in the the inclusive senseof of inclusive sense "including" "including" or "having" or "having" and notand not exclusive in the in the exclusive sense of sense of

"consistingonly "consisting only of'. of".

10 10

5004T-AU 5004T-AU 6

Claims (8)

CLAIMS CLAIMS

1. AAmethod 1. methodof of increasingthe increasing theaccuracy accuracyofofconveyor conveyor belt belt measurements measurements taken taken

whilstthe whilst thebelt beltisis moving movingby by ameliorating ameliorating the effects the effects of beltofwander, belt wander, said said 5 5 comprisingthethesteps methodcomprising method stepsof: of: mountingatat least mounting least one belt sensor one belt sensor on on aa belt beltsensor sensormount mount movable transversely movable transversely

to the to directionofofmotion the direction motion of the of the belt, belt,

providing aa motor providing motorto to move movesaid saidbelt belt sensor sensor mount mountininresponse responsetotoa abelt belt wander wander signal indicating signal indicating aadirection directionand andapproximate approximate magnitude ofthe magnitude of the belt belt wander, wander,

10 10 simultaneously sensing simultaneously sensingthe the current current location location of of each each edge of the edge of the moving belt moving belt

usingatat least using least one onepair pairofofedge edge sensors sensors located located at same at the the downstream same downstream belt belt locationsbut locations butononopposite opposite edges edges ofbelt, of the the belt, and and generatingsaid generating saidbelt belt wander wander signal signal if said if said pair pair of edge of edge sensors sensors indicateindicate said said belt belt edges are edges are both both moving movingininthe the same samedirection directionand andbybyapproximately approximatelythethe same same

15 15 magnitude. magnitude.

2. The 2. Themethod methodas as claimed claimed in in claim claim 1 wherein 1 wherein said said at at leastone least onebelt beltsensor sensorsenses senses a belt a belt property selectedfrom property selected from the the class class consisting consisting of remaining of remaining cover thickness cover thickness

and remaining and remainingsteel steel cord cord volume. volume. 20 20

3. The 3. Themethod methodas as claimed claimed in in claim claim 1 or 1 or 2 wherein 2 wherein said said edge edge sensors sensors areare

ultrasonic. ultrasonic.

4. The 4. Themethod methodas as claimed claimed in in anyany oneone of of claims claims 1-31-3 wherein wherein the the current current location location

25 25 of each of eachedge edgeof of thethe moving moving belt belt is sensed is sensed relative relative to a stationary to a stationary frame. frame.

5. Apparatusfor 5. Apparatus forincreasing increasingthe theaccuracy accuracyofofconveyor conveyorbelt beltmeasurements measurements taken taken

whilstthe whilst thebelt beltisis moving movingby by ameliorating ameliorating the effects the effects of beltofwander, belt wander, said said apparatus comprising: apparatus comprising: 30 30 at least at leastone onebelt beltsensor mounted sensor mounted on on aa belt beltsensor sensormount mount movable transversely movable transversely

to the to directionofofmotion the direction motion of the of the belt, belt, a motor a operatively connected motor operatively connectedtoto said said belt belt sensor sensor mount to move mount to movesame samein in

response to response to aa belt belt wander signal indicating wander signal indicating aadirection directionand andapproximate approximate

5004T-AU 5004T-AU 7 magnitudeofofthe 2020223635 24 2020 magnitude the belt belt wander, wander, at least one pair of edge sensors located at the same downstream belt locations at least one pair of edge sensors located at the same downstream belt locations

Aug but on but opposite edges on opposite edges of of the the belt belt and and arranged arranged to to simultaneously sense the simultaneously sense the current location of each edge of the belt, and current location of each edge of the belt, and

5 5 signal means generatingmeans signal generating to generate to generate saidwander said belt signal ifsignal belt wander if said said pair pair of edge of edge

sensors indicate said sensors indicate saidbelt beltedges edgesare areboth bothmoving moving in in the the same same direction direction and and by by

approximatelythe approximately the same samemagnitude. magnitude.

6. The 6. Theapparatus apparatusasasclaimed claimedininclaim claim5 5wherein whereinsaid saidatatleast least one one belt belt sensor sensor 10 10 senses senses a abelt beltproperty propertyselected selected fromfrom the class the class consisting consisting of remaining of remaining cover cover thickness and thickness and remaining remainingsteel steel cord cord volume. volume.

7. The 7. Theapparatus apparatusasasclaimed claimedininclaim claim5 5oror6 6wherein whereinsaid saidedge edgesensors sensorsare are ultrasonic. ultrasonic.

15 15

8. Theapparatus 8. The apparatusasasclaimed claimedininany anyone oneofofclaims claims5-7 5-7wherein wherein thethe currentlocation current location of each edge of the moving belt is sensed relative to a stationary frame. of each edge of the moving belt is sensed relative to a stationary frame.

20 20

Dated this Dated this 22nd day ofofJune 22nd day June 2020 2020

25 25 BEMO PTY BEMO PTY LTD LTD

By By FRASER OLD FRASER OLD&&SOHN SOHN 30 30 Patent Attorneys Patent for the Attorneys for the Applicant Applicant

5004T-AU 5004T-AU 8