7.Kiln Alignment

8/19/2019 7.Kiln Alignment

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Rotary Kiln MaintenanceRotary Kiln MaintenanceSeminarSeminar

Kiln Alignment


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Alignment Principles

Internal Alignment

Hot Kiln Alignment

Kiln AlignmentKiln Alignment


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Alignment PrinciplesAlignment Principles


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A kiln is considered aligned when the

center of rotation of the kiln shell atevery support lies on a straight line.


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Note that a kiln with only two supportsis always aligned, as there is always astraight line between two points.

Two Support Kiln


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A kiln can be misaligned in thehorizontal or in the vertical plane.

Horizontal Axis

Vertical Axis


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Consequences of MisalignmentConsequences of Misalignment

Misalignment changes the loading on thekiln supports and causes overstressing ofthe shell and supports.

3597 kN 7048 kN 2815 kN

3902 kN 6491 kN 3067 kN

10 mm


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Internal AlignmentInternal Alignment


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Internal alignment is normally used whenassembling a new kiln. A line of sight is shotthrough batter boards marking the kiln centers atthe shell section ends and at the tire locations.


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New kiln sections usually have steel spiderbracing with precisely marked centers. Ifnot, wooden batter boards can be prepared.



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The kiln shell’s center is found by scribing fourarcs on a target card tacked onto the batter board.


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Drawing diagonals at the arcs’intersections will locate the center.


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Removable targets with marked shell centers are

placed at each tire center and shell end. Thetheodolite’s line of sight is marked on the target andthe offset is measured.


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Note that if there is any top clearance present, the tirecenter is not the same as the kiln center. Alignmentcalculations must take hot running clearance into account.

Tire

centre

Kilncentre

S

TopClearance


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Roller

Adjustment

Field Joint

Adjustment

After measurements are taken the kiln isaligned by adjusting rollers and field joints.

Correcting MisalignmentCorrecting Misalignment


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Moving both rollers horizontally will movethe kiln center by the same amount.

h

h

h


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Roller adjustments to correct vertical alignment canbe calculated from the relationship of right triangles.

A

B

C

B

C

A2 + B2 = C2



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Moving one roller horizontally will move the kilncenter horizontally by half and vertically by onequarter (approximately ) of the distance.

1

½

¼


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Measurements and corrections canbe completed while the kiln isoperating.

The data collected indicates the realconditions as the kiln is operating.

Alignment errors can be correctedimmediately or during a planned kilnoutage.

Advantages

Hot Kiln AlignmentHot Kiln Alignment


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Mechanical Hot Kiln Survey Method

Laser Kiln Survey (LKS) Method



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Diameter of support rollers and live rings

using electro-mechanical instrument.

Temperature of the support rollers, liverings and kiln shell.

Creep and clearance between the kiln shellsupport pads and live rings.

Both methods utilize a variety ofmeasured data to determine kilns axis:



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Using a theodolite to establish a line of sightalong the kiln, the horizontal distances from theline of sight to each support roller is measured.

Mechanical AlignmentMechanical Alignment


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Using an optical level the elevations ofUsing an optical level the elevations of

the bearing base frames are determined.the bearing base frames are determined.


ΛΛΛΛ

s

f

j

F

a b

c

q

cleft cright

Tire centre

Kiln centre

dleft

dright


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Elevation markers on kiln piers shouldbe checked to see if a kiln pier has sunk.


ElevationMarkers


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DIGITAL CIRCUMFERENCE OF TIRE

A magnet and magnetic sensor recordstart/stop positions. Circumference is readon the digital readout to 0.1 mm accuracy.

MagnetRoller and Tire CircumferenceRoller and Tire Circumference


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ΛΛΛΛ

s

f

j

Fa b

cq

cleft cright

dleft dright



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Laser Kiln SurveyLaser Kiln Survey

Tire elevation and location can be determinedutilizing a laser theodolite from ground level.


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Laser measurement provides the mostaccurate method of kiln alignment.

Kiln Center Tolerances

Horizontal Plane ±±±± 1.5 mm

Vertical Plane ±±±± 2.5 mm


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7.Kiln Alignment

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