Alfa Lavalh - lcec.com · FRONT OM English EN OPERATOR’S MANUAL OPERATION SERVICE MAINTENANCE...

h

OM English EN

OPERATOR’SMANUAL

OPERATIONSERVICEMAINTENANCE

Decanter Centrifuge

Alfa LavalAlfa Laval

FRONT

Decanter Centrifuge Data Sheet

Decanter Specification, Type SG2-100 Machine No.: 5122361 Date of issue: 2009-06-12

Specification: 882004907-0

Process liquid: Min. 0°C (32°F) - max. 100°C (212°F)

Max. density of compact wet cake at max. bowl speed: 1.2 kg/dm³ Bowl Maximum main speed: 5300 rpm Bowl length: 709 Bowl diameter: 200 mm Beach angle: 10° Solids discharge type: 6 bushings Solids discharge radius: 61 mm Solids transportation aids, cylindrical section: Ribs Solids transportation aids, taper section: Ribs Material - hubs: AL 111 2349-02 (AISI 316) Material - bowl shell: AL 111 2349-83 (AISI 316) Material - bolts: A4-80 (AISI 316) Material - seals: Liquid outlet, type: 4 Liquid outlet, radius: 55 mm (fitted from factory: 63 mm)

Conveyor Material - flights: AL 111 2349 (AISI 316) Material - hub: AL 111 2349 (AISI 316)

Wear Protection Bowl solids discharge: Wear bushing in stellite, 6 pieces Part No. 61240489-01 Bowl feed zone liner: Conveyor flights: TM11 (flame sprayed nickel-chromium alloy) Conveyor feed zone: None Frame / casing: Wear liner in upper casing

Frame and Casing Material - casing / cover: Stainless steel (AISI 316) Inside surface of casing: Stainless steel cladding throughout Gaskets / seals - casing:

Drives Power supply: 3 x 460 V / 60 Hz Gearbox, type: Planetary - 2-stage Gearbox, max. torque: 0.4 kNm Gearbox, ratio: 1:45.6 Back drive: Variable Frequency Drive 3 kW IEC (400V, 50Hz/460V,

60Hz) - diff. speed 2 - 40 rpm at 0,4 kNm - (Back drive motor, 3.3 kW, 400VD/460VD, 5170rpm, 87Hz, part No. 61195700-50, Connect motor in Delta)

Back drive parts: Operating main speed: 5300 rpm Max. diff. speed and torque (at operating speed):

40 rpm / 0.4 kNm

G-force at operating speed: 3140 G Main motor: 11 kW, 2pol/3000rpm, 400V/460V, 50Hz/60Hz, Y/D-VFD

– part No. 61195703-00 Main motor, protection:

Documents & Drawings Manuals, language: Manuals in English Dimension drawing: 61242480 Diagram, decanter junction box: 61211237

Spare Parts Important: When ordering spare parts, always state:

• Machine number and type indicated above • Part number and designation • Quantity

DATASHEET

Noise Declaration Noise emission data for the decanter declared in accordance with the re-quirements in EN ISO 4871 and EN12547:

LwAd : Declared A-weighted sound power level from the decanter

LpAd : Declared A-weighted emission sound pressure level in a free field over a re-flecting plane at 1 m distance from the decanter

Uncertainty on declared values : LwAd : KwA=2 dB

LpAd : KpA=4 dB

The noise does not contain significant impulsive or tonal components and the peak C-weighted instantaneous sound pressure level LpCpeak is below 130 dB(C) at all operat-ing speeds.

The emission sound power level is measured according to ISO 9614-2 while operatingthe decanter with water as process medium. The sound pressure level is determinedfrom the measured sound power level according to EN ISO 11203.

The sound pressure level can vary –1dB to 2 dB at different positions around the decanter.

For decanters with hydraulic back drive some operating modes will give up to 2dB in-crease in sound pressure at the back drive end of the decanter.

The declared values are based on measurements conducted on typical new decanters.

Note that the sound pressure levels are based on free-field conditions and not guaran-teed values. In a normal indoor installation the sound pressure level will be significant-ly higher than the declared free-field sound pressure level due to the reflection ofsound from walls and surroundings.

In order to minimise the sound pressure level at the decanter it is recommended to in-stall the decanter in a room with low reflection of sound from the walls and alwayskeep the decanter in a properly maintained condition.

Operating Speed

[rpm]

Sound Power LevelLwAd

[B(A) re 1 pW]

Sound Pressure LevelLpAd

[dB(A) re 20 μPa]

5300 9.3 78

enNOI904.fm

Alfa Laval OMChapter Contents Page

0.0 1 Safety Instructions .............................................................. 1.0-1

2 Decanter Operating Principle ...................................... 2.0-1

2.1 Main Drive ...................................................................................... 2.1-1

2.2 Back Drive ...................................................................................... 2.2-12.2.1 Variable Frequency Drive (VFD) Back Drive ............................... 2.2-2

EN904003.TOC+ 0.0-1


3 Operation and Routine Maintenance .................... 3.1-1

3.1 Before First Start ........................................................................ 3.1-13.1.1 Noise and Vibrations ........................................................................ 3.1-2

3.2 Start/Stop procedures .............................................................. 3.2-13.2.1 Inspect Bowl ...................................................................................... 3.2-13.2.2 Before Start ......................................................................................... 3.2-1

3.2.2.1 Checkpoints ....................................................................................... 3.2-13.2.2.2 Decanters with Mechanical Seals (Optional Equipment) ........... 3.2-1

3.2.3 Start Decanter .................................................................................... 3.2-23.2.4 Stop Decanter .................................................................................... 3.2-2

3.3 Monitoring Operation ................................................................ 3.3-13.3.1 Overload ............................................................................................. 3.3-1

3.3.1.1 Causes of Overload ........................................................................... 3.3-23.3.1.2 Cleaning an Overloaded Bowl ........................................................ 3.3-2

3.3.2 Vibrations ........................................................................................... 3.3-33.3.2.1 Vibration Switch (Optional Equipment) ....................................... 3.3-3

3.4 Cleaning Procedures .................................................................. 3.4-13.4.1 Chemical Cleaning (Optional Equipment) .................................... 3.4-23.4.2 High Speed CIP ................................................................................. 3.4-63.4.3 Low Speed CIP .................................................................................. 3.4-7

3.5 Performance Optimization ...................................................... 3.5-1

3.6 Main Drive ...................................................................................... 3.6-1

3.7 Variable Frequency Drive (VFD) ............................................ 3.7-1

3.8 Lubrication ..................................................................................... 3.8-13.8.1 Main Bearings .................................................................................... 3.8-33.8.2 Conveyor Bearings ........................................................................... 3.8-43.8.3 Gearbox .............................................................................................. 3.8-5

3.9 Maintenance Tables .................................................................... 3.9-13.9.1 When to lubricate and to perform maintenance .......................... 3.9-2

Table 3.9.1 Lubrication ...................................................................... 3.9-2Table 3.9.1.1 Recommended Intervals for Maintenance .............. 3.9-3

3.9.2 Applicable Lubricants ...................................................................... 3.9-4Table 3.9.2 Lubricant, Parts to Lubricate ........................................ 3.9-4

0.0-2 EN904003.TOC+


4 Disassembling and Assembling ................................... 4.0-1

4.1 Rotating Assembly ...................................................................... 4.1-14.1.1 Remove Bowl ..................................................................................... 4.1-14.1.2 Install Bowl ........................................................................................ 4.1-44.1.3 Remove Large End Hub ................................................................... 4.1-74.1.4 Install Large End Hub ...................................................................... 4.1-74.1.5 Remove Small End Hub ................................................................... 4.1-94.1.6 Install Small End Hub ...................................................................... 4.1-94.1.7 Remove Gearbox ............................................................................... 4.1-104.1.8 Install Gearbox .................................................................................. 4.1-114.1.9 Fit New Solids Discharge Bushing ................................................. 4.1-12

4.2 Main Bearings ............................................................................... 4.2-14.2.1 Disassemble Main Bearing Large End ........................................... 4.2-14.2.2 Assemble Main Bearing Large End ................................................ 4.2-24.2.3 Disassemble the Main Bearing Small End ..................................... 4.2-54.2.4 Assemble Main Bearing Small End ................................................ 4.2-6

4.3 Conveyor Bearings ...................................................................... 4.3-14.3.1 Disassemble Conveyor Bearing Large End ................................... 4.3-14.3.2 Assemble Conveyor Bearing Large End ........................................ 4.3-34.3.3 Disassemble Conveyor Bearing Small End ................................... 4.3-54.3.4 Assemble Conveyor Bearing Small End ........................................ 4.3-6

4.4 Conveyor ......................................................................................... 4.4-14.4.1 Remove Conveyor from Bowl ......................................................... 4.4-14.4.2 Insert Conveyor into Bowl ............................................................... 4.4-2

4.5 Main Drive ...................................................................................... 4.5-14.5.1 Disassemble Main Drive .................................................................. 4.5-14.5.2 Assemble Main Drive ....................................................................... 4.5-34.5.3 Tighten V-belts .................................................................................. 4.5-44.5.4 Disassemble Mechanical Coupling ................................................ 4.5-54.5.5 Assemble Mechanical Coupling ..................................................... 4.5-6

4.6 Variable Frequency Drive (VFD) ............................................ 4.6-14.6.1 Disassemble VFD .............................................................................. 4.6-14.6.2 Assemble VFD ................................................................................... 4.6-1

5 Supplementary Documentation ................................. 5.0-0

EN904003.TOC+ 0.0-3

Alfa Laval Rev. 2008-01 OM
1.01.01 Safety Instructions
1.0

The Decanter

1. The decanter delivered must not be used to separate flam-mable, toxic, corrosive, or radioactive process mediawithout prior written approval from Alfa Laval.

2. Read this manual and the Operator's Manual before at-tempting to install or operate the decanter equipment,and follow all recommendations.

3. Do not operate the decanter with damaged or missingwarning labels.

4. Do not operate the decanter if the vibration level exceeds24 mm/sec (RMS) (US: 1 inch/sec).

5. Do not operate the decanter with feed temperatures ex-ceeding the limits stated on the DATA SHEET included inall three volumes of the Instruction Manual.

6. Never attempt to start the decanter with frozen water orfrozen or hardened process material in the bowl.

7. Do not exceed the maximum bowl speed or solids densityspecified on the decanter name-plate and DATA SHEET.

8. Do not operate the decanter without belt guards and otherguards provided.

9. Periodically check all the automatic shut-off devices andmonitoring systems for correct operation.

FAILURE TO FOLLOW THESE RULES MAYRESULT IN SEVERE PERSONAL INJURY ORPROPERTY DAMAGE.

1.0-1SAFETYIN.EN0

10. Do not attempt dismantling until the decanter has come to
a complete stop, the main power is shut off, and the dis-connected main switch is locked with a safety lock.

11. Do not operate the decanter if the bowl, motor, or sup-porting structure show cracks, pitting, holes, or grooves.

12. Do not use tools other than those recommended by AlfaLaval to dismantle and assemble the decanter.

13. Do not attempt to use the decanter for any application orprocess material other than that stated on the original pur-chase documentation without first consulting Alfa Laval.

14. Follow all lubricating procedures and schedules.

15. Check periodically - at least once a year - for loose bolts onfoundation and supporting structures, covers, hatchesand pipe connections of decanter and motor.

16. Do not get rags or loose clothing near rotating parts.

17. At all times follow the recommended sequence and proce-dures for dismantling, assembly, operation, and mainte-nance. Do not introduce new procedures without firstconsulting Alfa Laval.

18. Only allow trained personnel to operate, clean, dismantleor assemble the decanter.

19. Do not operate the decanter before the installation is com-plete.

20. Do not operate the decanter with any electrical motor run-ning in the opposite direction to that indicated by the ar-rows on the frame or otherwise specified.

1.0-2 SAFETYIN.EN0

21. If the decanter is fitted with a frequency inverter, make
sure that the maximum possible frequency will not causeoverspeeding of the decanter. At least two separate pro-tections against overspeed must be provided. See section6.9.

22. Do not turn on feed or water before the decanter has at-tained its full speed.

23. If the decanter is operated with hot, corrosive, or aggres-sive liquids, care should be taken that any incidental spill-age from the decanter cannot hit persons below the centreline of the decanter.

24. Never turn on feed or large amounts of hot, corrosive, oraggressive liquids when the decanter is at a standstill, asthese liquids might hit persons below the centre line of thedecanter.

25. Never start the feed pump or flush the decanter beforeopening the discharge valves or starting the dischargepumps, including any conveying means for the liquid andsolids phases.

26. When personnel are working on a decanter with a hingedcover, care should be taken that the cover is not closed un-intentionally by other persons or by moving machinery,which might cause injury.

27. Do not touch the solids phase discharging from the de-canter as hard lumps being ejected with high speed mightcause injury.

28. When using straps to lift the complete decanter or any ofits parts such as the rotating assembly, make sure to pre-vent the part hanging by the straps from sliding.

29. When lifting the decanter, use the slings specified on thedimensioned drawing.

30. The lifting eyes in the bearing housings, if fitted, must notbe used for lifting the bowl assembly.

of the ID manual.

1.0-3SAFETYIN.EN0

Electrical Installation
1. Install and earth all equipment in accordance with re-quirements of the Local Electricity Authority.

2. Use an “on-load” isolator or circuit breaker (a main switchfor switching off during run-up) on the main power sup-ply.

3. Check that the voltage and the frequency are in agreementwith labels on motors and other electrical equipment.

4. De-energize all equipment before connecting and discon-necting test equipment.

Repairs

1. Major repairs to decanter must not be made without firstconsulting with Alfa Laval.

In no circumstances should weld repairs, heating witha naked flame, or other alterations be made to bowl shells,bowl hubs, gearbox adapter, shafts, or other rotating partswithout prior written approval and instructions fromAlfa Laval. Failure to obtain this approval may result infailure of parts involved with possible serious damage toequipment, property, or personnel.

2. Do not operate the decanter on completion of the repairsuntil the belt and/or other guards are re-fitted.

1.0-4 SAFETYIN.EN0

3. Do not exceed the maximum load carrying capacity of the
lifting tools. Only use the lifting tools for the intendedpurpose.

4. Replace worn or damaged parts with only originalAlfa Laval parts.

Alfa Laval cannot be held responsible for any damageto property or for injury to persons if genuine parts arenot used.

5. Do not interchange bowl parts, since specific parts are bal-anced as a unit.

The Motor

1. Do not operate a decanter equipped with flame proof mo-tor(s) and control unit(s) until all enclosures have been as-sembled in accordance with the appropriate standards.

2. If a motor should become inoperative, immediately shutoff the power.

3. Always follow motor manufacturer's specifications onbearing lubrication.

4. Do not attempt to operate a motor that is overheated dueto frequent starts and stops. Allow motors to cool to am-bient temperature (as designated on the motor name-plate) before each restart.

Do not attempt to start motor unless the rotating elementsturn freely.

1.0-5SAFETYIN.EN0

Corrosion, Erosion and Pitting of DecanterEquipment It should be recognized that equipment sub-jected to severe erosive or corrosive environments may deteri-orate over a period of time, depending upon the severity of ex-posure and/or possible misuse. Users of high speed centrifu-gal equipment should be aware of this fact and also that ex-tremely high forces are brought into play when their equip-ment is in operation. Any weakening of highly stressed mem-bers by misuse, erosion, corrosion, chemical pitting, or stresscracking must be guarded against.The following points should be noted and the recommendedaction taken:
1. Inspect the outside of the bowl for erosion and corrosion,at least every two months.

2. Do not operate equipment when:

2.1 Holes are worn through rotating parts.2.2 Grooves greater than 2 mm (0.08 inch) deep are worn

in rotating parts.2.3 Evidence of cracks is present in rotating parts.2.4 Chemical pitting of 2 mm (0.08 inch) depth or greater

is present on rotating parts.

3. Chemical Pitting Observed:

All cases of chemical pitting, even under 2 mm depth,should be monitored carefully. This action is almost al-ways due to the breakdown of the passive film on stain-less bowl shell walls, in the presence of chlorides. This of-ten occurs under deposits that have not been cleaned fromthe outside of the bowl wall. High temperature and highacidity accelerate the action.

4. Pay special attention to the bolts assembling the bowl sec-tions. If the process liquid or cleaning agents contain chlo-rides, check these bolts at least once a year and exchangethem at least every three years. Contact Alfa Laval, if indoubt.

Contact Alfa Laval regarding the repair or replacement of pit-ted bowl shells or other parts.

1.0-6 SAFETYIN.EN0


2 - Decanter Operating Principle

The feed enters the decanter at the intersection of the conicaland the cylindrical part of the bowl through a central feed pipein the hollow drive shaft. After leaving the feed pipe, the feedsuspension is distributed into the rotating liquid in the bowland smoothly accelerated to the full rotational speed. The cen-trifugal force makes the solids settle at the bowl shell. Thescrew conveyor continuously transports the solids toward theconical end of the bowl and through conical bowl part.

The separation takes place throughout the total length of thecylindrical part of the bowl, and the clarified liquid dischargesat the large end where it flows over the rim of exchangeableand/or adjustable plate dams.

The solids are discharged from the small end by centrifu-gal force through outlet openings.

2.0-1nall2001.en0


Decanter with Baffle DiscThe space in the cylindrical and conical parts of the bowl, withthe baffle disc between them, act as two communicating ves-sels. The plate dams can be set to a smaller radius than that ofthe solids discharge (negative beach).

Then the heavy phase (the solids) is pressed under thebaffle disc by the hydrostatic pressure of the light phase (theclarified liquid).

ATTENTION The liquid and the solids are discharged at roughly the same radius,and consequently, during start-up, flushing, and irregularities inprocess, discharge of liquid through the solids discharge ports mayoccur owing to lack of solids in the bowl. This should be taken intoconsideration when the decanter is installed.

Figure 2.0.1

2.0-2 nall2001.en0

2.1 Main Drive
The decanter i driven by an electric motor. The motor shaftcarries a drive pulley, and motive power is transmittedthrough V-belts to the bowl pulley to drive the bowl.

2.1-1NALL2101.EN0

2.2 Back Drive
The purpose of the back drive system is to make it possible tocontrol the speed of the sunwheel shaft of the gearbox andconsequently to control the differential speed between bowland conveyor.

Two automatic back drives are available; one with Eddy Cur-rent Brake (ECB) and one with Variable Frequency Drive(VFD).

For the ECB back drive, two specialized controllers can beused; either the Differential Speed Controller (DSC) or theVariable Speed (VS).

For the VFD back drive, either the DSC or the Decanter CoreController (DCC) can be used.

See specific manuals for the DCC, DSC or VS for furtherinformation about the controllers.

2.2-1NALL2216.EN0

2.2.1 Variable Frequency Drive (VFD) Back Drive
The VFD Back Drive System consists mainly of three compo-nents, the specialized decanter back drive controller (DCC orDSC), a variable frequency drive (VFD) and a variable speedmotor.

The variable speed motor is coupled to the decanter gearboxeither inline with a flexible coupling or offset with belt andpulleys.

The motor speed and direction is directly controlled by vary-ing the electrical output voltage, and frequency from the VFD.The VFD receives its speed command signal from the backdrive controller and sends back a motor load or torque signal.If a motor encoder is used, then the quadrature signal fromthis is connected to the VFD for determining motor speed anddirection.

If the motor has to brake to obtain the set speed, then the brak-ing power could either be dissipated as heat in a resistor bank,or in case of a full four quadrant inverter be fed back on thegrid. If a VFD is also used for the main drive, then the powercould be fed back via a DC link between the main and backdrive inverters.

The back drive controller is master of the system, and calcu-lates the speed command signal based on the measured differ-ential speed and conveyor torque. To determine the differen-tial speed, the controller must have information about the gearratio, and measure both speed and direction of the motor/sunwheel shaft and the speed of the bowl.

contd...

2.2-2 NALL2216.EN0

The bowl speed is measured by an inductive speed sensor lo-cated on the decanter, and the sunwheel or motor speed anddirection of rotation is either determined by using two sepa-rate inductive speed sensors, or if an encoder is used, from oneof the channels of the motor encoder.
WARNING Care must be taken when setting up operational parameters.

Firstly, it must be ensured when setting up the speed range for thevariable speed motor that the conveyor can never rotate as fast as orgreater than the bowl speed. This could result in a plugged or cloggeddecanter and could even mean a risk of overspeeding the bowl. Thebowl speed is determined by the type of decanter and the process.

Secondly, it must also be ensured that the maximum load does notexceed the gearbox rating. This will result in damage to the gearboxand pinion shaft. The maximum gearbox load depends on the sizeand type of gearbox fitted.

contd...

2.2-3NALL2216.EN0


3 Operation and Routine Maintenance

3.1 Before First Start

ATTENTION Be sure the decanter has been properly lubricated according instruc-tions in section 3.8. If the decanter has been in stock for more than afew months, the grease in the main bearings might have stiffened,which makes it difficult to attain full speed. The remedy is to applynew grease while turning the bowl slowly by hand (see section 3.8.1).

Be sure that the transport safety devices (the yellow wedges) havebeen removed. Check that the bowl rotates freely in both directions.

WARNING In all decanters the bowl rotates at very high speeds. Very great en-ergy is accumulated and it is therefore essential that both the direc-tions concerning assembly of parts, starting, stopping and overhaul,and the safety precautions given are followed strictly.

3.1-1NALL3101.EN0

3.1.1 Noise and Vibrations
In spite of the most accurate balancing a rotating body is al-ways slightly out of balance. As the bowl and the conveyor aretwo separately balanced units rotating at different speeds, thenegligible unbalance of each unit will coincide, and a momen-tary increase of noise and vibration occurs in the machine.

The period of time between the moments when this hap-pens depends on the difference in the speeds of bowl and con-veyor. The higher the differential speed the shorter the inter-vals, and vice versa.

Increased unbalance caused by wear and/or accumula-tion of solids will increase the amplitude of noise and vibra-tion.

A practical hint: The differential speed of the conveyor canbe found by counting these vibrations for exactly one minute.

3.1-2 NALL3101.EN0

3.2 Start/Stop procedures
3.2.1 Inspect Bowl

A bowl which has not been cleaned, but left clogged by solidsafter operation must be cleaned before the decanter is restart-ed, because dried solids may cause severe unbalance andeventual generation of an overload condition. See section3.3.1.

3.2.2 Before Start

3.2.2.1 Checkpoints

If the decanter has stopped due to overload, the followingpoints must be checked before the decanter is started:

• Are the upper and lower casings free from solidsdeposits?

• Are the discharges open?

• Is the bowl easily rotated by hand?

• Are all guards correctly placed and properly secured?

3.2.2.2 Decanters with Mechanical Seals(Optional Equipment)

Before starting a decanter with mechanical seals, the gas sup-ply system for the seals must be activated and the flow andpressure of gas to the seals must be checked. If the decanter isto be used for inflammable substances, it must be purged withinert gas and it must be ensured that the oxygen concentrationhas gone down to a safe level before the machine is started.Also during run-down until the decanter has stopped, the gassupply to the seals must be activated. See section 3.10.1 ’Instal-lation, Start-up and Operation of Decanters with Circumferen-tial Seals’.

3.2-1NALL3201.EN0

3.2.3 Start Decanter
Release EMERGENCY STOP (in most cases: pull out theEMERGENCY STOP knob - or turn it as indicated by arrows).

Start the decanter motor.

Wait 2-4 minutes for the decanter to attain full speed with starconnected circuit before switching to delta connected circuit.

Start the belt conveyor or other transport means for dis-charged solids.

Open the feed valve (if any).

Start polymer pump (if used).

Start the feed pump.

3.2.4 Stop Decanter

ATTENTION When stopping a decanter with mechanical seals make sure that thesupply of gas continues until the decanter has stopped.

Stop feed and polymer pumps (if used), close feed valve (if fit-ted).

Before stopping, flush out with water of suitable temperature.Flush while the machine is running.

Stopping the decanter before its bowl is sufficientlycleaned may give rise to heavy vibrations both during decant-er rundown and during its successive run-up.

ATTENTION When flushing decanters for fat and oil applications, optimal flushingeffect is achieved by using flushing liquids holding temperatures abovethe melting points of the fats and oils run through the decanter.

Using e.g. cold water might cause solidified lumps of fat/oils to re-main in the decanter, which in their turn would give unbalance duringdecanter rundown and during its successive run-up.

Stop the decanter motor when the bowl is thoroughly flushed.Do not flush the decanter when it is inactive.

Press the CENTRIFUGE STOP button on operator panel.

3.2-2 NALL3201.EN0

3.3 Monitoring Operation
Make particularly sure that there is no increase in vibration.

Check the surface temperature of the main bearing housingsfrom time to time. A temperature rise may indicate a possiblemalfunction in the bearing.

The decanter can optionally be equipped with temperatureprobes for continuous monitoring of the bearing tempera-tures.

ATTENTION The alarm level for main bearing temperature is 100°C (212°F). Atthis temperature level the bearing must be monitored. Especially ifthe increase of temperature is very steep or appears without any ob-vious reason such as after lubrication of the bearing or increased feedor ambient temperature.

The shut down level is 110° C (230°F). At this temperature the de-canter must shut down immediately. If after a restart the tempera-ture again increases to 110°C (230°F), the bearing must be replaced.

After lubrication the temperature may remain high for some hours.

The decanter can optionally be equipped with automaticgreasing system for the main bearings, see Chapter 5 Supple-mentary Documentation.

3.3.1 Overload

If the centrifuge torque exceeds a certain limit, the control sys-tem will deactivate the feed permissive contact and stop thefeed and polymer pumps.

Under these circumstances the control system can be resetand the feed pump restarted from the control panel.

If the conveyor torque exceeds a higher limit, the main motorwill be also be switched off.

Then it is advisable to have the feed replaced by water un-til the bowl speed has reached 300 r p m.

When the bowl has stopped rotating, reset the control sys-tem to operative condition.

3.3-1N9043301.EN0

3.3.1.1 Causes of Overload
The causes of overload may be:

• Too high throughput.• Too high feed concentration.• The properties of the solids (prestraining or grinding the

process liquid before feeding it into the decanter may benecessary).

• Too low differential speed.• Solids clogging the discharge from the casing. (Main mo-

tor overload.)• Too hig bowl speed.

3.3.1.2 Cleaning an Overloaded Bowl

If the decanter has stopped due to too high torque on the con-veyor, and the decanter is unable to scroll itself free during anew start, the causes of overload may be as described above,and the only way to clean the bowl will be to disassemble thebowl according to instructions given in section 4.4.1.

When cleaning the conveyor, be careful to clean all of theflights to avoid unbalance when running the decanter after as-sembly.

ATTENTION It is forbidden to attempt to eliminate the overload on a decanter witha standard gearbox by fixing the sunwheel shaft and rotate the bowl,due to the fact that it can cause damage on either the gearbox, thespline shaft or the large end hub.

3.3-2 N9043301.EN0

3.3.2 Vibrations
If excessive vibrations occur while the bowl rotates, stop themain motor immediately and supply liquid to soften the vi-brations.

3.3.2.1 Vibration Switch (Optional Equipment)

To protect the decanter against damage due to heavy vibra-tion, it can be equipped with a vibration sensor which cuts offthe power supply to the main motor and the feed pump in caseof excessive decanter vibrations.

The control panel (or the motor starter) must be providedwith a terminal for the vibraswitch.

Being erected on vibration dampers, the decanter deflectsgreatly during starting and stopping, but these oscillations areso soft that they will not activate the vibraswitch.

Three types of vibration switches are available:

Vibration Level Monitor

See specific manual VLM for further information.

Vitec Vibration Switch

The standard factory-set levels are ¾ in/sec (19 mm/sec)alarm level and 1¼ in/sec (31 mm/sec) as decanter shutdownlevel.

For further details about the vibration switch, see sub-supplier's descriptions included in the decanter supply.

3.3-3N9043301.EN0

Robertshaw Vibration Switch (Fig. 3.3.2.1)
ResettingThis vibration switch is reset manually by pressing the resetbutton, see figure 3.3.2.1 below

AdjustingTo adjust this vibration switch to trip at the correct vibrationlevel, proceed as follows:When the decanter is not operating, turn the adjusting screwclockwise until the vibraswitch trips.

Then reset it and find the tripping point again. Repeat thisprocedure a couple of times to ensure that the correct trippingpoint has been found.

Then turn the adjusting screw counterclockwise one timeand a third.

ATTENTION Re-adjustment may be required if the vibraswitch shuts off the powersupply because the building where the decanter equipped with vi-braswitch is operating begins to vibrate heavily.

Figure 3.3.2.1 Resetting the Robertshaw Vibration Switch

Reset Button Adjusting Screw

3.3-4 N9043301.EN0

3.4 Cleaning Procedures
Before starting a cleaning process, please note that the belowprocedure is not product specific and therefore is only intend-ed as a guide.

Before the decanter is stopped, close the valve to the feed andraise the differential speed, if possible, in order to transportthe last solids remains out of the bowl. Always make sure totake precautions against outflow of fluids to other machineswhich provide further treatment of the solids after the separa-tion process, such as for instance sludge drier or the like. Thiscan be done by redirecting the decanter's slide gates or by-passsystem.

Instructions:

1. Flush the decanter with water until the discharged flush-ing water from the large end looks clean and clear.

ATTENTION On decanters with paring disc the flow must not exceed the capacityof the paring disc.

2. Switch off the main motor, but continue to flush. Shut offthe water before the bowl speed decelerates below 300rpm.

ATTENTION Never flush the decanter when the bowl is standing still or rotatingbelow 300 rpm (see section 3.8.2 ‘Conveyor Bearings’ regarding lu-brication).

3. Open the upper casing of the bowl and check visually ifboth upper and lower casings are clean. Check also ifthere is still product in the bowl. This is done by lookinginto the bowl through the holes of the large end hub andthe solids discharge.

4. Now check if the flushing had the intended effect on thebowl. This is done by turning the sun wheel shaft by handwithout moving the bowl.

3.4-1NALL3403.EN0

5. If item 3 and item 4 are not satisfactory, the decanter must
be accelerated to operating speed again, and the proce-dure is repeated from item 1. If it is not possible to prop-erly clean the bowl according to the above procedure, thebowl must be disassembled and then cleaned.

After having done the above procedure, the observationsshould be evaluated regarding time intervals of the flushingtime in order to obtain the optimum cleaning.

Note!The optimum flushing time of the decanter very much de-pends on the operating conditions.

• If the vibrations level is higher than normal during start-up, the time interval of the flushing of the bowl must be in-creased.

• If the vibrations are not too high at any time, the flushingis of appropriate length.

3.4.1 Chemical Cleaning (optional) (CIP = Cleaning in Place)

A chemical cleaning of the decanter is done in two phases:

• High speed

• Low speed

High speed:

Cleaning during high speed is normally done at a speed that is10-15% below the normal operating speed (rpm). This is doneto avoid unnecessary overloading of the main motor, as dur-ing this CIP-procedure smaller power consumption should beanticipated.

When the decanter is taken out of operation to run a CIP-pro-cedure, it is necessary to flush the decanter (see table 3.4.1).This is done during the high speed phase with hot water,which is flushed into the decanter to remove process remains.

3.4-2 NALL3403.EN0

During the flushing, the piping, the inlet parts, the bowl's ex-terior and the casing of the decanter are cleaned. Cleaning ofthe bowl's exterior is done in connection with deceleration ofthe bowl, as both the main motor and the cleaning fluid con-tributes to slowing down the bowl rotation.
The solids remains, which might still be in the bowl after thehigh speed cleaning, will be removed during the next phase,i.e. the low speed phase.

High Speed CIP

Bowldiameter

[mm]

Feedtube

[litre/hour]

CIP nozzles in casing/cover

at 3 bar[litre/hour]

200 1500 3000

280 5500 7400

353 10000 11000

360 10000 11000

450 20000 12000

480 25000 12000

575 45000 14000

740 100000 15000

Table 3.4.1

3.4-3NALL3403.EN0

Low speed:
In order to be able to run low speed CIP, it is a condition thatthe main motor is equipped with a frequency converter.

Cleaning at low speed is executed with a bowl speed below 1G at the bowl wall (see the bowl speeds in table 3.4.2).

The rotation direction of the bowl is reversed at certain inter-vals, which gives the intended effect of a washing machine.See sequence diagram page 3.4-10.

During the low speed phase, some of the cleaning fluid is lift-ed upwards onto the bowl wall from where the fluid hurlsdown on the conveyor hub. In this way a mechanical cleaningof the bowl and conveyor is carried out, which together withthe chemical action of the cleaning fluid improves the washingintensity and gives a good cleaning effect.

Low Speed CIP

Bowldiameter

[mm]

BowlSpeed

[rpm]

Feedtube

[litre/hour]

CIP radial hole in the feed tubeat 3 bar

[litre/hour]

200 95-115 350 -

280 80-95 1300 600

353 70-85 2500 600

360 70-85 3000 600

450 60-75 5000 600

480 60-70 6000 600

575 55-65 11000 600

740 45-55 25000 600

Table 3.4.2

3.4-4 NALL3403.EN0

In those cases where water alone cannot remove the deposits,chemicals such as sodium hydroxide (NaOH)/caustic sodacan be added in order to get a satisfactory result. To ensure apH value of 12 to 13, the solution must be 1.5-2.0%.
If necessary, cleaning with acid could be carried out as a goodsupplement to cleaning with caustic soda; a suitable agent isnitric acid (HNO3) with a concentration of approx. 1 pH value.

To intensify the effect of the use of the CIP-fluids, the chemi-cals are heated, by means of which the heat acts as a catalyst.

Typical scopes of application for caustic soda and acid are:

• NaOH (caustic soda) - Proteins, grease.

• HNO3 (acid) - Calcareous deposits

A detergent compound of NaOH with an admixture of a com-plex agent such as sodium polyphosphate, EDTA (ethylenedi-aminetetraacetic acid) or NTA (nitrilotriacetic acid) can beused.

Be aware that when using low speed CIP, the intervals be-tween lubrication are more frequent because of the low speedand the aggressive CIP-fluids. The combination of low speedand CIP-fluids increases the risk of eluviation of grease fromthe conveyor bearings (see section 3.8.2 ’Conveyor Bearings’re. lubrication).

Remarks to sequence diagram page 3.4-10:The duration of each cycle is to be individually determinedbased on the operating conditions at the site, where the de-canter is used.

Note!Alfa Laval expects that storage, handling, cleaning and re-moval of the used CIP-fluids is executed in accordance withthe legislation of the country concerned, in which the decanteris used.

3.4-5NALL3403.EN0

3.4.2 High Speed CIP
In the high speed phase the nozzles are activated in the casingat 3 bar, see the recommended flows in table 3.4.1.

Sequence:(see diagram page 3.4-10)

Step I, Flushing:

Shut off the main motor and the feed. Redirect the by-pass sys-tem of the decanter and flush with clean hot water through thefeed tube and the nozzles of the casing when the speed has de-creased to 90% of the operating speed. The bowl speed mustnot decrease below 50% of the operating speed.


Step II, Acid:

Supply for a short period of time hot CIP-fluid in the form ofacid through the feed tube and the nozzles of the casing. TheCIP-fluid is led back to the CIP-tanks through the by-pass sys-tem.

Step III, Flushing:

Flush with hot water through the feed tube and the nozzles ofthe casing.


Step IV, Flushing:

While the main motor is switched off, continue flushing thedecanter with cold water through the feed tube and the noz-zles of the casing until the rotation has reached 300 rpm. Thebowl speed must not decrease below 50% of the operatingspeed. The flushing with water will contribute to slowingdown the bowl. While the decanter decelerates the rotations, itis emptied for cleaning fluid. At the moment when the decant-er bowl begins to rotate at low speed, the rotation direction isreversed and the decanter goes directly to low speed CIP.

3.4-6 NALL3403.EN0

ATTENTION When the decanter rotates in opposite direction of the normal rota-
tion, the solids are transported towards the small end and the solidsoutlet. This reversed rotation is especially important on decanterswith paring disc in order to avoid solids from blocking the paringdisc outlet.

Note!If the flushing water or the CIP-fluids are recycled, these fluidsmust be cleaned of solids and impurities before use.

The CIP-fluid that comes from the feed tube via the paringdisc, can be pumped directly back into the CIP-system. Thefluid that is sprayed through the nozzles of the casing comesout of the fluid discharge funnel in the casing. The fluid fromthe funnel will be polluted by solids, too, and should thereforebe cleaned before reuse.

3.4.3 Low Speed CIPDuring the low speed phase, the solids remains are flushed offof the bowl inner side and the conveyor hub. The recommend-ed flows and speeds can be seen in table 3.4.2.

Low speed CIP is not started until the bowl rotates in oppositedirection of the normal rotation direction. In this way the sol-ids are transported out through the solids discharge of thebowl. The rotation direction is not changed back until no moresolids come out of the solids discharge. This will, of course, re-sult in a longer intermission at the stage VI (see sequence dia-gram page 3.4-10).

The CIP-fluids that are returned to the CIP-tanks must becleaned of impurities before reuse. It is important that thequantity and concentration (pH-value) of the CIP-fluids arecontrolled regularly, since otherwise the intended cleaning ef-fect of the CIP-fluids cannot be obtained.

3.4-7NALL3403.EN0

Sequence:(see diagram page 3.4-10)
Step V, Caustic soda:

Now when the decanter runs backwards and the speed is be-low 1 G (see table 3.4.2 for speeds), hot caustic soda is added,which is sprayed through the feed tube and the radial hole ofthe feed tube. The CIP-fluid is led back to the CIP-tanks.

Step VI, Flushing:

Flush with hot water through the feed tube and the radial holeof the feed tube. Check visually that no more solids come outof the solids discharge.

Step VII, Flushing:

Stop the main motor, but continue to flush the decanter withcold water through the feed tube and the radial hole of thefeed tube.

Flushing with water will contribute to slow down the bowl.While the decanter decelerates the rotations, it is emptied forcleaning fluid. At the moment when the decanter’s bowl startsrotating at low speed, the rotation direction is changed back topositive rotations.

Step VIII, Acid:

Supply for a short period of time hot CIP-fluid in the form ofacid through the feed tube and the radial hole of the feed tube.

Step IX, Flushing:

Flush with hot water through the feed tube and the radial holeof the feed tube.

Step X, Flushing:

Stop the main motor, but continue to flush the decanter withcold water through the feed tube and the radial hole of thefeed tube.

3.4-8 NALL3403.EN0

Flushing with water will contribute to slow down the bowl.While the decanter decelerates the rotations, it is emptied forcleaning fluid. At the moment when the decanter’s bowl startsrotating at low speed, the rotation direction is changed back tonegative rotations.
Step XI, Caustic soda:

Supply for a short period of time hot CIP-fluid in the form ofcaustic soda through the feed tube and the radial hole of thefeed tube.

Step XII, Flushing:

Flush with hot water through the feed tube and the radial holeof the feed tube.

The procedure can be repeated from step VII to XII to the ex-tent that is required.

Step XIII, Final Flushing:

Before the CIP-procedure is ended, be sure to finalize thecleaning by flushing with cold, clean water. The flushing mustbe done through the feed tube and the radial hole of the feedtube as well as through the nozzles of the upper casing.


The first times a CIP-programme is run, all procedures and ob-servations should be written down in preparation for a follow-up evaluation and optimization of the times and flow quanti-ties until the most optimum cleaning is achieved.

If desired, please contact your local sales company to jointlywork out the most optimum cleaning procedure that is neces-sary for your specific application.

3.4-9NALL3403.EN0

co
ntd.

..3.4

-10

Sequ

ence

dia

gram

Nor

mal

ope

ratin

g sp

eed

[ Bow

l spe

ed ]

Rep

etiti

on10

- 50

% <

op.

spe

ed

Production

> 30

0 [r

pm]

1G >

[rpm

]

0 [r

pm]

[ Tim

e ]

1G >

[rpm

]

Tem

p.:

pH :

Med

ia:

60 -

70°

6-7

Wat

er20

- 30

°1-

2A

cid

60 -

70°

12-1

3So

da5

- 10°

6-7

Wat

er

Function

Feed

sto

pB

y-pa

ss (W

,A,S

)W

*A

*W

WS

*W

WA

WW

SW

WA

WW

SW

WFe

ed tu

beC

IP -

Noz

zles

CIP

- R

adia

l hol

e

Step

III

IIIIV

VVI

VII

VIII

IXX

XIXI

IVI

IVI

IIIX

XXI

XII

XIII

CIP

- ph

ase

Hig

h sp

eed

CIP

Low

spe

ed C

IP

* B

y-pa

ss (W

) to

Wat

erta

nk;

B

y-pa

ss (A

,S) t

o C

IP-ta

nks

3.4-10 NALL3403.EN0

3.5 Performance Optimization
The decanter can be adjusted to suit individual requirementsby varying the following control parameters:

Bowl Speed

By varying the rotational speed of the bowl, the G-force can beadjusted to suit the application. The higher speed, the betterseparation.

Liquid Level

Adjust the liquid level (pond depth) to give the optimal bal-ance between liquid clarity and solids dryness by selecting dif-ferent plate dams.

In general terms, the centrate becomes more clear and thecake more wet when diminishing the liquid radius and viceversa.

Differential Speed (Δn or ΔRPM)

The dryness of the cake can be increased when operating witha lower differential speed, but the centrate will be less clearand vice versa. The torque increases with the lower Δn.

The differential speed can be regulated automatically tocompensate for varying content of solids in the feed.

Feed rate

The lower feed rate, the better separation.

contd...

3.5-1NALL3501.en0

3.6 Main Drive
ATTENTION Store spare V-belts in a dry and cool place.Never roll up the V-belts. Sharp bends will damage them.

Before installing new belts, check the pulleys for wear, using,if necessary, a profile and groove gauge.

When installing new belts, rotate the belt drive a few turns be-fore measuring the belt tension, repeating this procedure untilthe belt tension is correct. For the belt tension values, refer tosection 4.5.

Check the belt tension after 0.5-4 hours of full load opera-tion and then every 4000 hours, referring to section 4.5 for thebelt tension values, and not forgetting to rotate the belt driveevery time before measuring the belt tension.

All types of V-belts used for the main drive should normallybe exchanged every 16000 hours.

N9043601.en0 3.6-1

3.7-1NALL3709.EN0

Alfa Laval Rev. 1997-11 OM3.7 Variable Frequency Drive (VFD)

Refer to section 5 ’Supplementary Documentation’ for the spe-cific descriptions of the electrical motor and the frequency in-verter and follow the given instructions for service and main-tenance.

3.8
contd...

Figure 3.8.11. Main Bearing Large End 2. Main Bearing, Small End

3.8-0 N9043801.EN0

3.8 Lubrication
(Fig. 3.8.1 shows where the lubricating nipples are located)

The lubricants must be kept in a dry and cool location (15-20°C=59-68°F). The containers must be kept closed to prevent con-tamination of the lubricants by dust and moisture.

When lubricating, refer to the lubrication and lubricant tablesin the next section of this manual.

3.8

3.8-1N9043801.EN0


Figure 3.8.2

1. Main Bearing Large End 2. Main Bearing, Small End3. Discharge opening, Large End 4. Discharge Opening, Small End5. Conveyor Bearing, Large End 6. Conveyor Bearing, Small End

3.8-2 N9043801.EN0

3.8.1 Main Bearings (Nipples 1 and 2 in Fig. 3.8.2)
Always lubricate the main bearings while the decanter is run-ning, and preferably, just before stopping it for any prolongedperiod of time.

This will ensure the best distribution of grease, which inits turn gives optimum lubrication condition and maximumprotection against contamination of the bearings.

ATTENTION Using larger quantities than those recommended may lead toover-greasing and thereby problems of high bearing temperatures oreven bearing breakdown.

Hint: If the decanter is taken out of service for a certain periodevery week, lubricate the main bearings just before stoppingthe decanter.

If the decanter is taken out of service for more than two weeks,its main bearings must be lubricated every two weeks duringthe inactive period.

Using the grease gun included in the standard decanterdelivery, apply 1.5 grammes (0.05 oz) - 1 stroke - of grease toeach bearing. Then turn the bowl slowly by hand.

3.8-3N9043801.EN0

3.8.2 Conveyor Bearings (Nipples 5 and 6 in Fig. 3.8.2)
Lubricate the conveyor bearings with the decanter stoppedand the power effectively disconnected from the main motor.

Using the grease gun included in the standard decanterdelivery, apply 40 g (1.4 oz) - 27 strokes - of grease to eachbearing.

ATTENTION Sufficient amount of lubricating grease applied: If the lubricatinggrease flows out from the grease discharge opening located behind themain bearing housing, add no more grease.

3.8-4 N9043801.EN0

3.8.3 Gearbox (Fig. 3.8.3)
Change the oil in the gearbox at the intervals given in Table3.9.1 ’Lubrication Table’.

In the outer surface of the gearbox there are two plugs (drainplugs) screwed into two holes.

Drain the oil from the gearbox into a suitable container as fol-lows:

Rotate the gearbox until one of the drain plugs points up-wards.

First remove the upper plug and then place a can underthe gearbox. Rotate the gearbox by 180° and remove the sec-ond plug. After draining, fit a plug in the lower hole. Thenplace a hopper in the upper hole.

Refill the gearbox with oil of the quality and quantity giv-en in the lubrication table.

After filling, fit the second plug into the upper hole.

Figure 3.8.3

3.8-5N9043801.EN0

3.9 Maintenance Tables (Tables 3.9.1, 3.9.1.1, and 3.9.2)
General Information

For proper lubrication and maintenance, see the tables on the followingpages.

Lubrication: In cases where no Alfa Laval lubricants are available, othertypes of lubricants acceptable by Alfa Laval may be used; refer to the table3.9.2.

The alternative lubricants are only to be used, if this does not result in anincreased bearing temperature level.

WARNING Use of non acceptable lubricants will void Alfa-Laval’s warrantywith respect to damages resulting from such incorrect use.

ATTENTION If changing from one grease type to another, it will be necessary todisassemble all bearings and remove old grease by washing the bear-ing itself in petrol or a similar detergent. Other parts must be care-fully cleaned of old grease. When having reassembled the cleanedbearing parts, the new type of grease can be applied.

Table 3.9.1Table 3.9.2

3.9-1N9043901.EN0

3.9.1 When to lubricate and
to perform maintenance

Lubrication Table

First Running Intervals Lubricant Quantity

Main Bearings

Lubricate during running at 50-150 rpm

See table 3.9.1.1 See table 3.9.21.5 g (0.05 oz) at each grease nipple *)

*) When injecting grease with the grease gun***) included in the standard decanterdelivery:

1 stroke = approx 1.5 g (0.05 oz)7 strokes = approx 10 g (0.35 oz)

Conveyor Bearings

Before starting the decanter for the first time.

See table 3.9.1.1 See table 3.9.240 g (1.4 oz) at each grease nipple*) **)

**) NB! It is important that grease is flowing out from the grease outlet in mainbearing houses. Remove used grease before start.

Gearbox

Check oil level (see section 3.8.3). If necessary, add oil.

See table 3.9.1.1 Alfa Laval 61203671-10

Statoil Mereta 320 0.7 litres (0.74 quarts)

Table 3.9.1

***) For P/N, see table 3.9.2 or Spare Parts Catalogue, List TOOLS.

3.9-2 N9043901.EN0


1) 2000 hours, unless specified otherwise in separate motor manual.

Recommended Intervals for Maintenance

Item Interval [hours]8h Daily 24h Service

Main Bearings Lubrication Product temperature < 60°C (140°F) 100 *) 300 *)Product temperature > 60°C (140°F) 50 *) 150 *)

Conveyor Bearings LubricationProduct temperature < 60°C (140°F) 200 *) 300 *)Product temperature > 60°C (140°F) 100 *) 150 *)

Gearbox Oil Leakage Check Once a month

Once a month

Oil Level Check 1000 1000Oil Change 2000 2000 Change lip seal(s) atsunwheel shaft(s) ** If leaking If leaking

GearboxSpline Shaft Lubricate splines At each

major serviceAt each

major serviceMotor(s) Lubrication 20001) 20001) Mechanical Coupling

Check or replacement offriction blocks 2000 8000

V-belts Tightening up and Check 2000 2000 Change 16000 16000

Bowl Check for wear and corrosion. For decanters operating at high tempera-tures and/or high chloride levels in feed,check bolts connecting bowl section forcorrosion and stress corrosion cracks.See safety instructions for details.

1000 1000

Solids Discharge Wear Protection

Check If damaged or excessively worn,fit new immediately.

1000 1000

Safety Equipment Check functioning of: All alarm devices Safety equipment

2000 2000

Labels Check: Name-plate and warning labels.Replace if not readable.

2000 2000

Foundation bolts Check tightening 4000 4000 Vibration dampers Check

Fit new, if necessary. 4000 4000

Table 3.9.1.1

* At least once a month** For P/N, see Spare Parts Catalogue

3.9-3N9043901.EN0

3.9.2 Applicable Lubricants
■ Lubricants applied to the decanter when delivered

▲ Lubricant applied to conveyor bearings on sanitary decanters

❑ Lubricants accepted by Alfa Laval

Δ Lubricant accepted by Alfa Laval for sanitary decanters

**) ATTENTION If changing from this grease type to another, it will be necessary todisassemble all bearings and remove old grease by washing the bear-ing itself in petrol or a similar detergent. Other parts must be care-fully cleaned of old grease. When having reassembled the cleanedbearing parts, the new type of grease can be applied.

contd...

Lubricant Parts to Lubricate

Brand Type MainBearings

ConveyorBearings

Alfa Laval 61203671-50 Grease ■ ■

61203671-40* Grease ▲

BP Energrease LC2 Grease ❑ ❑

Shell Alvania RL2 Grease**) ❑ ❑

Cassida EPS 2* Grease ΔSKF LGHP 2 Grease ❑ ❑

Texaco Starplex EP2 Grease ❑ ❑

Table 3.9.2

* Food Grade Grease

3.9-4 N9043901.EN0


4 Disassembling and Assembling

WARNING Do not make any disassembly/assembly operations on the decanterunless the main power is shut off, and the disconnected main switchis locked with a safety lock.

Replacing parts

To ensure trouble-free operation of the decanter, great caremust be taken during replacement of parts:

• Contacting and sliding surfaces, as well as O-rings andseals must be care fully cleaned.

• Always place removed parts on a clean, soft surface toavoid scratching the surfaces.

• Ensure that screws used to pull parts from each otherhave smooth ends.

O-rings, Seals, and Gaskets

Check O-rings, seals and gaskets for defects.

Check that O-ring grooves and sealing surfaces are clean.

After replacing an O-ring, check that it fills the groove com-pletely and that it is not twisted.

Ensure that seals are mounted with the open end pointing thecorrect way. See illustrations.

4.0-1NALL4001.EN0

Special tools Always use the recommended special tools for removing,disassembling, assembling, and mounting the bowl. In case ofnegligence of this point, Alfa Laval accepts no liability for pos-sible damage to the parts.
Alfa Laval supplies a variety of special tools and accesso-ries to facilitate maintenance of the decanter. See volume SPC(Spare Parts Catalogue).

When lifting the decanter assembly use theslings specified on the dimensioned drawing.

When Lifting Minor Decanter Parts by Strapsalways use lifting straps having a load capacity of minimum1000 kg (2200 lbs).

Vibration Dampers Check regularly and change those crumbled and damperswhose rubber has swelled or cracked. Do not run the decanterif any of its dampers is defective.

4.0-2 NALL4001.EN0

Spare Parts Kits
Alfa Laval supplies three types of spare parts kits for the de-canter:

The intermediate kit for main bearings and conveyorbearings, respectively, contain rubber parts for the main bear-ings and the conveyor bearings.

The major kit for main bearings and conveyor bearings, re-spectively, contains parts necessary for the complete overhaulof the decanter. It includes all sealing components and bear-ings. See volume SPC (Spare Parts Cataloque).

The gearbox kit includes the lip seal(s) for the sun wheel(s)and the O-ring between the splined nave and the gearbox cov-er.

4.0-3NALL4001.EN0

4.1
Figure 4.1.1

4.1-0 N9044101.EN0

4.1 Rotating Assembly
4.1.1 Remove Bowl (Figs. 4.1.1, 4.1.2 and 4.1.3)

WARNING Do under no circumstances loosen or remove the upper casing whilethe bowl is rotating.

Remove the screws [1] holding the upper casing and removethe casing.

Disassemble the main drive according to instructions in sec-tion 4.5.1.

Remove the four screws [7] and the feed tube [5].

Disassemble the countershaft transmission according to theinstructions in section 4.6.1.

Remove the four screws [2] and the wear liner [3].

Remove the four dowel pins [6] by means of the jacket nut [8]as shown in Fig. 4.1.2.

Remove the four dowel pin outer sleeves [9] by means of thespecial T-tool* as shown in Fig. 4.1.2.

Remove the eight screws [4] holding the pillow blocks.

contd...

* For P/N, see Spare Parts Catalogue

4.1-1N9044101.EN0


Figure 4.1.2

4.1-2 N9044101.EN0


Now remove the bowl assembly by means of the lifting slingas shown in Fig. 4.1.3.

Carefully lift the bowl assembly off the lower casing and placeit on a table or on two wooden trestles or the like.

Secure the bowl assembly with wedges to prevent it fromrolling.

Figure 4.1.3

4.1-3N9044101.EN0

4.1.2 Install Bowl (Figs. 4.1.1, 4.1.2 and 4.1.3)
Place the lifting sling around the bowl as shown in Fig. 4.1.3.

When installing the bowl, clean the pillow block contact sur-faces and the frame before lowering the bowl into place.

Lower the bowl assembly onto the frame.

ATTENTION If the gearbox is equipped with a reaction arm, as shown in Fig. 4.1.3,then be very careful not to damage it when lowering the bowl assem-bly.

Either remove the reaction arm during assembly or turn it upwards.

After the bowl has been placed and the pillow blocks aligned,the dowel pins [9] and [6] must be driven in.

Tighten the eight screws [4] securing the pillow blocks toa torque of 81 Nm (716 in-lbs).

Assemble the main drive according to the instructions in sec-tion 4.5.2.

Insert the feed tube [5] and secure with the four screws [7].

Install the wear liner [3] and secure with the four screws [2].

Assemble the countershaft transmission according to the in-structions in section 4.6.2.

Close the upper casing and secure with the screws [1].

4.1-4 N9044101.EN0


this page intentionally left blank

4.1-5N9044101.EN0


Figure 4.1.4

4.1-6 N9044101.EN0

4.1.3 Remove Large End Hub (Fig. 4.1.4)
This procedure describes how to remove the large end hubwith the gearbox assembled to it. For removal of the gearboxfrom the large end hub, see section 4.1.7.

Remove 11 of the 12 long screws [3], loosen the last one, andleave it in place until the end hub [1] is ready to be removed.

The end hub [1] can now be jacked off: Using two of the screws[3] as jacking screws, clear it off the bowl.

Be careful not to damage the needle bearing [2].

Remove the loosened long screw [3] left in place and pull outcarefully the end hub [1].

Remove the two screws [3] used as jacking screws.

4.1.4 Install Large End Hub (Fig. 4.1.4)

This procedure describes how to install the large end hub withthe gearbox assembled to it. For assembling the gearbox to thelarge end hub, see section 4.1.8.

Grease the outside of the O-rings [4] and [5]. Fill up withgrease the needle bearing outer race [2] and distribute thegrease with the fingers. Do not fill grease in the free space onboth sides of the needle bearing [2], because it is impossible tofit the large end hub [1], if the space around the bearing iscompletely filled up with grease.

Place the large end hub [1] on the bowl, being careful not todamage the needle bearing [2].

Fit the 12 screws [3] and tighten them to a torque of 7 Nm(62 in-lbs).

4.1-7N9044101.EN0


Figure 4.1.5

4.1-8 N9044101.EN0

4.1.5 Remove Small End Hub (Fig. 4.1.5)
Remove the conveyor according to instructions given in sec-tion 4.4.1.

Remove the 12 screws [3] and jack off the small end hub [1] bymeans of two of the screws [3].

Pull out the end hub [1].

Remove the two screws [3] used as jacking screws.

4.1.6 Install Small End Hub (Fig. 4.1.5)

Grease the outside of the O-rings [4] and [5].

Place the small end hub [1] on the bowl, being careful with theball bearing [2].

Fit the 12 screws [3] and tighten them to a torque of 7 Nm (62in-lbs).

Fill up with grease the ball bearing outer race [2] and distrib-ute the grease with the fingers. Do not fill grease in the freespace on both sides of the ball bearing [2], because it is impos-sible to fit the small end hub [1], if the space around the bear-ing is completely filled up with grease.

Fit the conveyor according to instruction given in section 4.4.2.

4.1-9N9044101.EN0


4.1.7 Remove Gearbox (Fig. 4.1.6)

ATTENTION When removing or installing the gearbox, always suspend it from ahoist or the like to avoid excessive load to the splined shaft. Use thelifting sling* as shown in Figure 4.1.6.

Remove the six screws connecting the gearbox to the gearboxadapter.

Place the lifting sling* as shown above.Suspend the gearbox from a hoist or the like and jack it off,

using two jacking screws into the threaded jacking holes.

Carefully pull out the suspended gearbox.

Remove the two jacking screws again when the gearbox hasbeen removed.

Figure 4.1.6


4.1-10 N9044101.EN0

4.1.8 Install Gearbox (Figs. 4.1.6)
Apply an ample amount of grease to the splined shaft and thesplined hub in the conveyor.

Don’t forget the O-ring on the splined shaft ([2] in Figure4.3.1).

Push the gearbox assembly with splined shaft carefully intoplace.

Rotate the sunwheel shaft a few turns, to make the splinesengage.

Insert the six screws assembling the gearbox adapter to thegearbox and tighten them to a torque of 24 Nm (212 in-lbs).

4.1-11N9044101.EN0


4.1.9 Fit New Solids Discharge Bushing (Figs. 4.1.7)

Before fitting the sludge bushing, both end hubs and the con-veyor must be removed from the bowl according to the proce-dures in sections 4.1.5, 4.1.3, and 4.4.1 of this book.

Use a soft hammer to force out the old bushing. Hold a handunder the bushing - or place some rags in the bowl, to preventdamage to the inside of the bowl.

Clean the holes in the bowl carefully.

Insert the bushing into the hole using a soft hammer. Ensurethat the edge on the bushing is parallel with the end surface ofthe small end hub.

Figure 4.1.7

4.1-12 N9044101.EN0



4.1-13N9044101.EN0

4.2
Figure 4.2.1

4.2-0 N9044201.EN0

4.2 Main Bearings (Fig. 4.2.1)
4.2.1 Disassemble Main Bearing Large End (Fig. 4.2.1)

Prior to disassembling the large end main bearing, the gearboxmust be removed according to instructions given in section4.1.7.

Remove the eight screws [6].Using two of them as jacking screws, pull off the gearbox

adapter [2], tightening the jacking screws equally to avoidpulling out the adapter [2] askew.

Place a standard two-armed puller as shown in Figure 4.2.2and remove the complete bearing assembly consisting of pil-low block [3], ball bearing [4], and bearing cover [7].

Remove the four screws [17] and the bearing cover [7].

Use a Ø3 mm mandrel to remove the ball bearing [4] from thepillow block [3], through the holes [A], taking care that themandrel does not damage the pillow block [3].

Figure 4.2.2

4.2-1N9044201.EN0

4.2.2 Assemble Main Bearing Large End (Fig. 4.2.1)
Insert the ball bearing [4] into the pillow block [3] and greasethe balls.

Fit the bearing cover [7] on the pillow block [3].

Insert the four screws [17] attaching the bearing cover [7] tothe pillow block [3] and tighten them.

Press, with the pressure acting on the inner race of the ballbearing [4], the assembly onto the pinion.

Carefully clean the contact surfaces between the gearboxadapter [2] and the pinion.

Place the gearbox adapter [2] on the large end pinion.

Fit the eight screws [6]. Tighten them to a torque of 24 Nm(212 in-lbs), tightening them crosswise a few times to ensuretightening of all eight screws to the correct torque.

Install the gearbox according to the instructions given in sec-tion 4.1.8.

4.2-2 N9044201.EN0



4.2-3N9044201.EN0


Figure 4.2.3

4.2-4 N9044201.EN0

4.2.3 Disassemble the Main Bearing Small End
(Fig. 4.2.3)

Remove the eight screws [12].Using two of them as jacking screws, pull off the V-belt

pulley [11].

Place a standard two-armed puller as shown in Figure 4.2.4and remove the complete bearing assembly, consisting of pil-low block [9], roller bearing [10], and bearing cover [15].

Remove the four screws [19] and the bearing cover [15].

Use a Ø3 mm mandrel to remove the roller bearing [10] fromthe pillow block [9], through the holes [A], taking care that themandrel does not damage the pillow block [9].

Figure 4.2.4

4.2-5N9044201.EN0

4.2.4 Assemble Main Bearing Small End (Fig. 4.2.3)
Fit the bearing cover [15] onto the pinion.

Heat the roller bearing inner race [10] by means of an induc-tion heater or in an oven to approximately 80°C (175°F) and fitit onto the inner pinion; be sure it seats fully against the shoul-der of the pinion.

Insert the roller bearing outer race [10] into the pillow block [9]and grease the rollers. Push carefully the assembly onto thebearing inner race [10].

Insert the four screws [19] attaching the bearing cover [15] tothe pillow block [9] and tighten them.

Carefully clean the contact surfaces between the V-belt pulley[11] and the pinion.

Place the V-belt pulley [11] on the small end pinion.

Fit the eight screws [12] and tighten them to a torque of 7 Nm(62 in-lbs).

4.2-6 N9044201.EN0



4.2-7N9044201.EN0

4.3
Figure 4.3.1

4.3-0 N9044301.en0

4.3 Conveyor Bearings (Fig. 4.3.1)
4.3.1 Disassemble Conveyor Bearing Large End

Remove the large end hub according to instructions given insection 4.1.3.

Remove the four screws [1] and the ring [3].

Remove the needle bearing inner race [5] by means of a smallstandard two-armed puller as shown in Figure 4.3.2.

Figure 4.3.2

4.3-1N9044301.en0

Remove the snap ring [10].
Using the special puller* as shown in Figure 4.3.3, pull offthe needle bearing outer race [5] .


Figure 4.3.3

4.3-2 N9044301.en0

4.3.2 Assemble Conveyor Bearing Large End
(Fig. 4.3.1)

If the end flange [7] has been removed, assemble the parts inthe following order:

Fit the O-ring [12] in the end flange [7].Fit the cover plate [11] and secure with the four screws[13].Fit the O-ring [9] in the end flange [7].Insert the end flange [7]. Fit the 12 screws [8] and tighten

them to a torque of 7 Nm (62 in-lbs).

Heat the needle bearing inner race [5] by means of an induc-tion heater or in an oven to approximately 80°C (175°F) and fitit onto the inner pinion; be sure it seats fully against the shoul-der of the pinion.

Fit the two O-rings [4] and [6] and grease them.

Fit the needle bearing outer race [5] onto the large end hub. Fitthe snap ring [10]. Fill up with grease the needle bearing outerrace [5] and distribute the grease with the fingers. Do not fillgrease in the free space on both sides of the needle bearing [5],because it is impossible to fit the large end hub, if the spacearound the bearing is completely filled up with grease.

Fit the ring [3] and secure with the four screws [1].

Place the conveyor into the bowl according to the instructionsgiven in section 4.4.2.

Install the large end hub according to the instructions given insection 4.1.4.

4.3-3N9044301.en0


Figure 4.3.4

4.3-4 N9044301.en0

4.3.3 Disassemble Conveyor Bearing Small End
(Fig. 4.3.4)

Remove the small end hub according to the instructions givenin section 4.1.5.

Remove the 12 screws [20] and the ring [21].Using the outer part of the ball bearing inner race [16] and

the puller tool* as shown in Fig. 4.3.5, pull off the ball bearingouter race [16].

Remove the inner half of the ball bearing inner race [16] byhand or use a brass mandrel. Be careful not to damage the pin-ion.


R

Figure 4.3.5

4.3-5N9044301.en0

4.3.4 Assemble Conveyor Bearing Small End
(Fig. 4.3.4)

Fit the inner half of the ball bearing inner race [16] onto thepinion.

Fit the O-rings [14].

Fit the ball bearing outer race [16] into the small end hub.

Fit the O-ring [15] in the ring [21].

Fit the ring [21] and secure with the 12 screws [20].

Fill up with grease the ball bearing outer race [16] and distrib-ute the grease with the fingers. Do not fill grease in the freespace on both sides of the ball bearing [16], because it is impos-sible to fit the small end hub, if the space around the bearing isfilled up with grease.

Insert the conveyor into the bowl according to the instructionsgiven in section 4.4.2.

Install the small end hub according to the instructions given insection 4.1.6.

4.3-6 N9044301.en0

4.4 Conveyor
4.4.1 Remove Conveyor from Bowl (Fig. 4.3.4)

Remove the large end hub according to instructions given insection 4.1.3.

Remove the small end hub according to instructions given insection 4.1.5.

Remove the 10 screws [19]. The ring [17] can be removed bymeans of the two long M3 threaded bars*.

Carefully pull out the conveyor 2-300 mm by hand. Place asling around the conveyor hub and connect the sling to a hoist.Now pull out the conveyor.

The outer half of the ball bearing inner race [16] can be re-moved by hand when the conveyor has been pulled out.

contd...


4.4-1N9044401.EN0

4.4.2 Insert Conveyor into Bowl (Fig. 4.3.4)
Place a sling around the conveyor hub and connect the sling toa hoist. Carefully insert the conveyor into the bowl until thesling hits the end of the bowl. Remove the sling again andcarefully push the conveyor into the bowl by hand.

CAUTION Be careful not to cut your fingers, when pushing the conveyor intothe bowl.

Fit the outer part of the ball bearing inner race [16] and the ring[17] with the O-ring [18] fitted.

Fit the 10 screws [19] and tighten them to a torque of 7 Nm (62in-lbs).

Install large and small end hubs according to the instructionsgiven in sections 4.1.4, and 4.1.6, respectively.

4.4-2 N9044401.EN0

4.5
Figure 4.5.1

4.5-0 N9044501.EN0

4.5 Main Drive
This decanter can be equipped with a mechanical coupling, inorder to reduce the starting current and avoid a star/delta re-lay. The motor should be connected in direct mode (delta cou-pled).

The starting current will vary from 1.5 up to 2.5 times the nom-inal current depending on temperature, condition of the cou-pling, etc.

The normal starting time is between 60 and 100 seconds. If thebearings are filled up with grease or if the ambient tempera-ture is low, the starting time may increase or it could even beimpossible to start the decanter, because the overlaod relay(thermistor) will switch off the power to the motor. In this caseit may be necessary to wait ½-1 hour before the decanter canbe started.

The starting time will also increase if the mechanical couplingitself is hot or the friction blocks are worn.

4.5.1 Disassemble Main Drive (Fig. 4.5.1)

Remove the feed tube and the upper casing.

Loosen the four screws [6] and elevate the motor bracket [10]by means of the two elevating screws [4].

Remove the two V-belts [3] from the pulleys.

Remove the motor with motor plate, and remove the centricscrew [16], the snap ring [15] and the washer [17].

Fit the thrust plate* [26] by means of three M8x20 screws [23],then demount the complete coupling with the M16x60 screw[24].


4.5-1N9044501.EN0


Figure 4.5.2

4.5-2 N9044501.EN0

4.5.2 Assemble Main Drive (Fig. 4.5.1)
Fit the coupling onto the motor shaft. First install the snap ring[15] and the washer [17], then install the thrust plate* [26] bymeans of three M8x20 screws [23], and pull the coupling ontothe shaft with a M10 or ½” UNC screw [24].

Demount the tool* and refit the screw [16].

Align the pulleys so that their placing is within 1 mm asshown in Figure 4.5.2.

Install the two V-belts [3] in the grooves of the pulleys andtighten them by means of the two screws [5].

Tighten the V-belts [3] to 250 N-300 N for new belts and 200 N-250 N for used belts as per instructions given in section 4.5.3.

Secure the motor bracket [10] with the four screws [6].

Install the upper casing and the feed tube.


Figure 4.5.3

1 Indicator Arm2 Rubber Finger Loop3 Pressure Surface4 Pocket Clip5 V-belt6 Pressure Spring

4.5-3N9044501.EN0

4.5.3 Tighten V-belts
Using the tester illustrated in Figure 4.5.3 above, adjust thebelt tension as follows:

1. See how to hold the tension tester and choose one of theways a, b, or c as shown in Figure 4.5.4.

2. Position the tester on the belt midway between the twopulleys with the flange on the bottom against the upperedge of belt.Take care that the indicator is completely pushed down inthe tester body.

3. Position the tester loosely on the belt to be measured andpush slowly with one finger in the above way (Fig. 4.5.4,A, B, C) on the pressure surface.

4. Avoid contact of tester with more than one finger duringthe measuring process.

5. When your hear a CLICK, stop pressing immediately; theindicator arm remains in measure position.

6. Remove tester carefully so that the indicator arm is notmoved and read the belt tension where the top surface ofthe indicator arm crosses the scale as shown in Figure4.5.5.

Figure 4.5.4

4.5-4 N9044501.EN0


7. For safe reading mark the spot of the upper side of the in-dicator with a thumbnail on the scale and then turn thetester sideways.

8. Increase or decrease the belt tension depending on themeasuring result until it is within the desired tension.

4.5.4 Disassemble Mechanical Coupling (Fig. 4.5.1)

Remove the centric screw [16], the snap ring [15] and thewasher [17], and pull off the coupling assembly from the mo-tor shaft.

Remove the eight screws [11] and the cover plate [12]. Removethe snap ring [18] and pull off the assembly consisting of thepulley [1], the ball bearings [14], the ring [22] and the snap ring[13].

Remove the snap ring [13], the ball bearings [14] and the ring[22], if the ball bearings [14] should be replaced.

Remove the screws [21] and the friction blocks [20].

Figure 4.5.5

4.5-5N9044501.EN0

4.5.5 Assemble Mechanical Coupling (Fig. 4.5.1)
Fit the holders [19] onto the nave [2]. Fit the friction blocks [20]and secure with the screws [21].

Fit the ball bearings [14] and the ring [22], if it has been re-moved, and the snap ring [13].

Fit the assembly consisting of the pulley [1], the ball bearings[14], the ring [22] and the snap ring [13] onto the nave [2]. Fitthe snap ring [18].

Fit the cover plate [12] and secure with the eight screws [11].

Fit the coupling assembly onto the motor shaft. Fit the washer[17], the snap ring [15], and the centric screw [16].

Fit the coupling assembly onto the motor shaft.

4.5-6 N9044501.EN0



4.5-7N9044501.EN0

4.6
Figure 4.6.1

4.6-0 N9044602.EN0

4.6 Variable Frequency Drive (VFD)
4.6.1 Disassemble VFD (Fig. 4.6.1)

Loosen the screw [11] and push the coupling part on to thesunwheel shaft of the gearbox so that the driving pins are free.

Place a sling around the VFD [1] and attach the sling to a hoist.Remove the four screws [2] and remove the VFD [1].

4.6.2 Assemble VFD (Fig. 4.6.1)

Place a sling around the VFD [1] and attach the sling to a hoist.Lift the VFD [1] into its place and refit the four screws [2].

Turn the coupling part on the sunwheel shaft so that the driv-ing pins are aligned with the holes in the other coupling part,and push the coupling part into place. There should be an airspace of 3-4 mm (1/8 inch) between the two halves. Tightenthe screw [11].

4.6-1N9044602.EN0

5.0-0NALL5001.EN0

Alfa Laval Rev. 1994-09 OMy

5 Supplementary Documentation

Date post:	16-Feb-2019
Category:	Documents
Upload:	phungbao
View:	234 times
Download:	3 times