Installation & Alignement of Rotating Drums [PDF]

Zitiervorschau

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 1 of 9

1. INTRODUCTION The scope of this procedure specification covers the steps and the minimum checks for the Installation and the Alignment of Horizontal Rotating Drums, to be performed by staff or by contractor. This specification does not relieve the supplier of its responsibility in regards to the quality of work: operation under load, without vibrations and without efforts, after alignment. If the supplier offers an alternative, that differs from described in this specification, or there are contradictions between this specification and his standards or provisions, he must explicitly indicate and justify them in his offer.

2. INSTALLATION Rotary drums, whether RT diffusers, beet washers, pulp or sugar dryers, lime slakers, dry soil separators, etc, are an integral part of sugar mills. As an extremely valuable investment, protecting this investment with routine maintenance and proper knowledge can help a rotary drum to lead a long, productive life. Proper installation and preventative maintenance can mean the difference between a drum with a long life ahead, or a drum with serious problems. Trunnion rollers. Support the weight of the drum. Riding rings. Add structural support for the drum, and a place for pressure to be absorbed. The riding rings ride on the support trunnion rollers. Thrust rollers. Thrust rollers hold on the riding ring side to stop the drum from drifting, or moving horizontally 1.1.

Proper Rotary Drum Base Installation

Proper base installation is the first step in preventative rotary drum maintenance. The importance of a proper base installation can be compared to that of a foundation for a house; a house foundation done improperly will result in disastrous results and many long-term repairs. A proper base install will help reduce adjustments needed at start-up in order to obtain optimal operation. One such adjustment is the bearings. Typically, on a drum with a slope, bearings need to be slightly skewed in order to allow proper float between thrust rollers. If trunnion bases are not installed correctly, it can result in the need for a substantial increase in bearing adjustments. The overall longevity of a drum is also increased with a proper base install. Improper drum alignment is one of the most common causes of rotary drum damage and failure. This is because misalignments in the base can propagate through the drum and cause wear and damage to components such as the trunnion rollers, drive components, and thrust rollers. Misalignment essentially causes the drum to ride harder against the thrust roller, thus wearing faster. It also can cause grooves or gouges to form on the roller face itself. Proper drum base installation will help to ensure that the drum properly ‘floats’ between thrust rollers.

1.2.

Foundations, base structures and trunnion rollers

 Foundations (in the case of drums installed on concrete foundations) It is an indispensable condition that the foundation piers be executed in accordance with the dimensions, both in length, height and elevation, that the designer indicates in his drawings. These dimensions must be checked. The height dimensions in the foundation drawings always correspond to the finished drum installation, or to the underside of the trunnion roller base structure... The distance between foundations or piers of the trunnion rollers shall also be checked. (Allowance ± 0.6 ‰) These dimensions must also be checked in relation to the axis of the drum. The dimensions of the positions of anchor studbolts of a pier with respect to another must also be checked, such that frames are parallel. (Allowance ± 0.6 ‰)

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 2 of 9

 Metal bedframes (In the case of drums installed on steel structure) The dimensions between the anchors for the trunnion rollers base structures shall be checked before mounting them. (Allowance ±0.6 ‰)  Trunnion rollers base structures The height and leveling of the trunnion rollers base structures shall be checked and corrected, by snapping them with metal supplements if necessary until a precision of 0.03 mm/m is achieved. When base structures are mounted on concrete foundations precaution shall be taken that the frame rests on the concrete and not on the leveling nuts, in order to correct potential loosening because of retraction of the concrete, or because of stretching of the studbolts.  Trunnion rollers Driving station of trunnion rollers The driving trunnion rollers station is located nearer to the product entrance and their roller shafts shall always be parallel to the axis of the drum. Guiding station of trunnion rollers The guiding trunnion rollers shafts shall always be parallel to each other and parallel to the drum during the Installation stage; though, in operation, they do not necessarily have to be parallel to the axis of the drum. Trunnion rollers shafts, in both driving and guiding stations, must be exactly parallel to each other in the installation stage and exactly parallel to the axis of the drum (maximum allowance in deviation from parallel is ± 0.1 % of the dimension). I.e., the inclination of the drum and trunnion rollers base structures must also be the same. (Allowance: ± 5% of the angle indicated by the designer). Three measurements of the diameter of the trunnion rollers shall be made and the roundness of the same must be verified. These three measures: one in the center and other two 50 mm from the sides of the trunnion rollers. (Allowance ± 2 ‰) Diameters and roundness of the riding rings shall be equally checked. Taking three measurements, one in the center and the other two at 50 mm from the sides of the track. (Allowance: ± 2‰). Geometry of roller stations The triangle that forms the axis of the drum with the trunnion rollers shafts must be ideally equilateral at each roller station. Such a geometry is subdivided into two right-angled triangles, with an angle of 30º ±1, between vertical line from the center of the riding ring and an imaginary line of union between the centers of the trunnion rollers , this geometry is that must prevail, and not the 60º main. Where angle is deviated more than 5º of 30º expected, the manufacturer shall be consulted about if he has designed the geometry of the drum other than what this specification says.

See enclosed diagrams:

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 3 of 9

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Note 1. Note 2. Note 3.

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 4 of 9

The vertical line that passes through the center of the riding ring has to be coincident with the center of the base structure, as previously marked on this. Parallelism between roller stations, i.e. distance A = A´, must be assured The seats of the shells of bearings, apart from being equal, must be at the same level.

Drum The drum fully welded and with its mechanized finished, provided with the riding rings, but without the girth, shall be placed by means of a crane on top of the trunnion rollers. Next, the axial thrust rollers can be tightened to their frames with the slack mentioned in the drawing. Driving gear The gear girth, in several pieces, shall be assembled around the mechanized path in the drum. It shall be able to be rotated without shocks. The allowed deviation shall be maximum 0.05 times de module. The pinion shall be mounted on the plane fixed by the reducer shaft. The gear girth shaft and the gear pinion shafts, on the drums so designed, shall be carefully adjusted parallel to each other, as well as parallel to the axis of the drum. Primitive diameters shall be marked both in the Girth and in the Pinion. The deviation between the primitive diameters shall be ≤ 0.05 x module. Both gears must maintain tangency; and, hence, should the primitive diameters not be marked, the distance from the head of the tooth of the Girth gear and the foot of the tooth of the pinion gear shall be checked (free space on bottom) equal to 0.2 to 0.25 x module.

Slack in axial thrust rollers As mentioned, the axial thrust rollers shall be installed for the riding ring on the side of the product input, with the slack mentioned in the drawing. The drum shall be able to travel free between the thrust rollers and precisely, in such a way that it does not pushes heavily against one of the thrust rollers. The axial slack in the drum is achieved by a small adjustment of the trunnion rollers in one riding ring. If necessary, in two riding rings. This adjustment must begin in the trunnion rollers station that is in the side of the product output.

3. ALIGNMENT Misalignment is one of the most common problems faced when working with rotary drums. Though aligning a drum is a simple solution, leaving a drum out of alignment can result in major problems. Once all the checks to verify that the base has been properly installed are done, proceed as follows: 1.3.

Test run without load

Without product been fed, the drum shall undergo a test for long enough as to reach the stationary regime of operation (minimum 1 hour, recommended 8 hours), observing and correcting especially the following points: Prior to the test  Reducer and bearings shall be provided with the prescribed quantity of oil or grease. During the test

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 5 of 9

 Warming, noise, and vibration of reducer bearings, axial retention roller bearings or pressure at 10-minute intervals and the Trunnion rollers bearings, are checked at 10 minutes interval.  Pinion and Girth gear must exactly touch one other at the primitive diameter (deviation ≤ 0.05 x module). The pinion must be in contact along the entire width of the tooth.  The Guiding Trunnion rollers shall be placed always parallel to each other, so that the drum goes back and forth between the axial retention or thrust rollers; or, at least, that the drum does not charge continuously on one of these rollers. A clearance of 0.1 x width of riding ring shall be kept between both axial retention rollers. Never adjust the reaction of the drum with the motor driven trunnion rollers, which must be always parallel to the axis of the drum.

3.2.

Test run under load

Once the good performance without load has been achieved, it is necessary to repeat all tests with the drum in permanent load for long enough (at least 8 hours), correcting the alignment, if applicable, with the guiding trunnion rollers.

4. WAY OF ACTING ON GUIDING TRUNNION ROLLERS To correct the axial thrust of the drum, one must act on the guiding trunnion rollers station, taking into account that these trunnion rollers shafts have to be always parallel. ( entrada = product input ; galetes guía = guiding trunnion rollers )

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For a drum with clockwise rotation, when looked at from the side of product input, if the guiding trunnion rollers are moved according to D, the drum will move in E direction.

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For a drum with clockwise rotation, when looked at from the side of product input, if the guiding trunnion rollers are moved according to D', the drum will move in the E´ direction.

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 6 of 9

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 7 of 9

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For a drum with anti-clockwise direction when been looked at from the side of product input, if the guiding trunnion rollers are moved according to I, the drum will move in F direction.

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For a drum with anti-clockwise rotation when looked at from the product input, if the guiding trunnion rollers are moved according to I', the drum will move in the F´ direction.

In each trunnion rollers station, one can distinguish between the pushing roller and the pulled roller. Looking in the axis direction and when the drum turns clockwise, the roller on the right is the one pushing the drum and the one in the left in been pulled by the drum. The pushing roller shall be adjusted in such a way that there is some separation to the side where the drum must turn; therefore, in such a way that in the side where the drum must run there will be no contact between the roller and the surface of the riding ring. For this purpose, the bolts that fix one support of the bearing of the roller shall be slightly loosened. Next, the two pressure bolts of one support of the bearing shall be turned 1/3 to ½ pitches, according to the desired adjustment. Next, the pressure bolts of the support of the bearing shall be tightened. The pulled roller shall be adjusted next, with the same procedure; always in a way that the shafts of both trunnion rollers are left parallel.

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 8 of 9

5. GUARANTIES The Supplier guaranties that all the alignment process has been done according to this specification and that all measures are within the allowances specified in the same. If detected problems can be due to a misalignment by the supplier, he shall take care at no cost for the buyer.

6. TECHNICAL DOCUMENTATION The supplier, after the alignment of the equipment, shall deliver a dossier with documentation as follows: 

Dimensions of location of foundations or foundation piers (shafts, distance between piers, location of the shafts with respect the drum axis).

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Dimensions of location of the axes of the trunnion roller base structure.

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Dimensions of the locations of the trunnion rollers shafts.

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Diameter and roundness of the trunnion rollers.

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Diameter and roundness of the riding rings

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Geometry of base structures with respect to the drum.

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Records kept of temperatures and vibrations.

7. OPERATOR TRAINING

Operator Training A properly trained operator is also key to a healthy rotary drum. Training operators on how to correctly inspect and maintain drum components will help prevent and catch potential issues. Operators that do not know what to look for could interpret situations as normal wear and tear, when in fact they are early signs of serious problems. Operators also need to be skilled in making adjustments to a rotary drum, as improper adjustments to a drum in operation can cause serious wear or damage, as is the case with the drum bearings. As a drum experiences normal wear, bearings may require adjustment to maintain the proper “float” between thrust rollers. Adjusting the bearings too much, too little, or unevenly can lead to serious damage. Training drum operators on things such as preventative maintenance, maintenance record keeping, and bearing skewing is a necessity in protecting the investment of a rotary drum, and potentially reducing future maintenance costs and downtime. Operators should also know to look for when a drum is in need of realignment. As a drum experiences normal wear and tear, it will gradually fall out of perfect alignment and need to be realigned. When a drum is running properly, and aligned correctly, it should run smoothly, with little to no contact with the thrust rollers. Drive components should turn smoothly with no excessive chatter or vibrations. These signs can be mistaken for normal wear and tear, but are actually signs that the drum is in need of some maintenance and/or repair. Regularly maintenancing and inspecting your rotary drums is one of the best things you can do to prolong the life of your rotary drums, as well as to minimize maintenance costs and downtime. Importance of Rotary Drum Alignment Misalignment is one of the most common problems faced when working with rotary drums. Though aligning a drum is a simple solution, leaving a drum out of alignment can result in major problems. Routinely having a

INSTALLATION & COMISSIONING OF ROTATING DRUMS Document nr.:

Owner: Made by: Date: JGR 04/12/2012 Issue: 0 Sheet nr: 9 of 9

rotary drum re-aligned is an important part of preventative maintenance, and the overall longevity of a rotary drum. What causes a drum to be misaligned? A misalignment is often the result of an improper base installation. Misalignment also occurs naturally, as a drum experiences normal wear and tear, causing the drum to gradually fall out of perfect alignment. For this reason, it is important to routinely have a drum re-aligned. How do you know if your drum is misaligned? Misalignment causes a drum to ride harder against the thrust roller, therefore wearing faster. This excessive riding can result in grooves and/or gouges. There are several tell-tale signs that can be a good indication that a rotary drum is out of alignment: 

Excessive wear on the trunnion roller

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Damage to the trunnion roller

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Excessive wear on the thrust roller

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Damage to the thrust roller

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Pinion/girth gear wear

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Pinion/girth gear damage

In addition to this, watching a drum run can indicate that it is time for a re-alignment. A working drum that is properly aligned should have little to no contact with thrust rollers. Drive components should run smoothly, without excessive chatter or vibrations.