Rolled Baking Band

Rolled Baking Band

Wire Belt Company’s Rolled Baking Band is designed primarily for ovens common to the baking industry, where an extremely flat carrying surface is required for the direct baking of biscuits and cookies.  These belts are often installed in biscuit baking tunnel ovens in lengths in excess of 100 metres with baking zone temperatures up to approximately 310°C.

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Rolled Baking Band also known throughout the industry as “Z Belts” is created by forcing a duplex unilateral spiral woven mesh through a rolling process to achieve a completely flat, smooth surface and a reduced belt thickness, without compromising heat efficiency.  The design creates a belt of low mass, high strength with good air circulation.  The belt is friction-driven by means of a large diameter drum, commonly placed at the out feed of the tunnel oven.  

By providing a flat, uniform surface, Rolled Baking Band is suitable for conveying both soft and hard dough through baking processes whilst ensuring an even heat transfer across the whole belt width.  Rolled Baking Bands may not be suitable for soft doughs with a high fat content where the dough will flow into the mesh in the baking process.

Typical Applications:

  • Cooking
  • Heating
  • Baking
  • Elevating
  • De-Elevating
 
The open area of the mesh can be varied to suit the application. For example, where soft dough is being conveyed we will supply a tight mesh to ensure complete product support. Conversely, meshes can be supplied with an increased open area for applications where heat efficiency is a major concern.

Rolled Baking Bands may not be suitable for soft doughs with a high fat content where the dough will flow into the mesh in the baking process.

Rolled Baking Bands features a hooked edge finish, eliminating the risk of welded joins becoming dislodged and contaminating product and to ensure maximum flexibility of the belt edges around rollers.

There are 4 standard belts which are listed in the table below:-

Available Specifications

  Belt Type
Z47 Z47R Z28* Z48
Wire Diameter (mm) 1.2 1.5 1.0 1.3
Pitch (mm): 8.2 8.5 6.3 8.5
Belt Thickness (mm): 2.2 2.8 1.8 2.4
Weight/m² (Kg): 7.0 11.2 6.5 7.4
Max. Width (mm): 1550 1530 1500 1550
Min. roller diameter for belt flexibility (mm): 300** 300** 300** 300**

* Not recommended for high temperature applications.  Designed for light loads with belt lengths up to 100 mtrs.
** The nominal oven drive and idle infeed drum roller diameter would be approximately 1 mtr (dependent upon oven length and process).  For new installations with belt lengths in excess of 100 mtrs please confirm full details of the application to our Technical Sales Team for assessment.

Material:  Carbon Steel

All belts are delivered marked with the direction of operation plus 10 connection join coils.

Important Note: Our belts are manufactured on a bespoke basis to suit your exact requirement.  Please ensure that the exact full replacement belt length is stated on your enquiry/order.  We do not supply short belt lengths to join onto an existing belt. DO NOT attempt to join on to an existing belt. 

Each belt is supplied with an included control length on each end, with a matching number of apertures across the width.  For minor belt length adjustment these control lengths can be cut back equally to suit.  If this is necessary please contact Technical Sales to confirm the maximum belt length reduction without affecting performance.  

For more information on which mesh will best suit your application, please contact our technical sales team.

Tracking of Friction Driven Mesh Belts

Belt track off is one of the major causes of belt failure. Incorrect tracking will lead to edge damage and early failure of the belt.
 
The recognised principle is that a friction driven belt will always track perpendicular to the roller over which it passes.  This principle holds good for all rollers in the system.
 
The conveyor should be set up to run with all rollers parallel and level to each other. 
  • As a general rule if the end rollers are not parallel the belt will track off to the short side.
  • Make sure all support beds are level and symmetrical about the centre line of the conveyor.
  • Ensure that the conveyor framework runs straight between the idle infeed and the discharge (drive) roller.
  • Ensure belt support surfaces are free from obstructions (e.g. protruding framework)
  • Do not use crowned rollers to support or drive the belt at any position in the circuit.

Caution: Incorrect installation may result in permanent damage to your belt.

Before installing the belt it is important that the conveyor structure is set up as per the above instructions in a proper aligned and level condition.
 
For belt installation please refer to the “Installation Guidelines”.  Once the belt is installed and set to run in the slow speed mode careful attention should be paid to ensure straight tracking of the belt.  If the belt tracks off to one edge then the following procedure for true tracking should be used which generally means adjusting horizontally the position of the belt support rollers.

During the procedure of belt tracking DO NOT alter the end roller positions once they have been checked and set according to the instructions above.  It is important that they run parallel and level.
 
The following are guidelines for the proper tracking of woven steel beltings: 
  1. To check for proper tracking first mark the belt at several positions down the length at an equal position in from the edge of the belt.  The edge of the belt can also be used if free and clear of any covers or guards. 
  2. The belt should now be run for several complete revolutions at slow speed to allow for settling out of the belt to its running position.  Once the belt has settled to position then measure any track off by means of the belt mark or belt edge relative to a point on the conveyor frame at the infeed end.  This will then indicate the direction and amount of belt track off. 
  3. To adjust the belt tracking please refer to the sketch below and adjust the return support rollers as per indicated in the instructions. 
  4. As a general guideline the roller closest to the infeed should be set at approximately 1¾ times the belt width away from the idle infeed roller.   Adjusting this roller may be sufficient however if you need additional tracking then adjust each roller in turn working away from the infeed.  TIP:  For large amounts of belt tracking correction it is more effective to move many rollers a small amount rather than say one or two rollers a large amount.  If the conveyor has a full wrap snub roller in the return way then adjustment of that roller may be more effective as the full wrap of belt on this roller will produce more lateral belt movement for any given amount of adjustment.
  5. At each stage of adjustment check the lateral belt movement against the previously set reference point at the infeed.  Once the belt lateral movement is stable the belt is then tracked and the rollers should be firmly secured in position.
  6. As final check move to the discharge and check for any lateral belt movement.  If there is movement of the belt at this point then adjust any carry way rollers in a similar fashion to previously.  Adjusting rollers closest to the discharge first and then moving back down the conveyor if further adjustment is required.  In general however if the belt is supported on a symmetrical chevron pattern of wear strips then the belt should self-track at the discharge.
Various other methods of belt tracking can be used under limited circumstances:-
  • Steel angle edge plates, which may be faced with low friction plastic contact surfaces. 
  • Vertical edge rollers.  These have only a single point of contact with the belt and should be used in multiples to help alleviate high pressure contact on the belt edge.
  • Hyperbolic edge rollers which offer a straight line of contact with the belt edge over the length of the roller when set at the designed angle of operation.
 
 
Any of the above can be used as a temporary measure until the belt can be re-tracked as described in the main text above.  They can also be used where the normal method of tracking is not possible or the conveyor is short with light loading, low tension and low speed.
 
There are 6 golden rules when tracking the belt:
  1. Always operate the belt with minimum of belt tension to ensure slip free drive.
  2. Always operate the belt with the minimum belt speed.
  3. Do NOT push the belt edges with excessive force to guide the belt. 
  4. Any type of belt tracking should start at the point of least belt tension.  Normally at the infeed end return way.
  5. Under no circumstances should flanged or crowned rollers be used in an attempt to track the belt.  Both will permanently damage the belt.
  6. The starting point for any edge guides should be no closer than 2 x the belt width from either the drive or infeed idle roller or any other roller where the belt contact is in excess of 30°.
Note:  For Rolled Baking Bands edge roller or guides are NOT recommended.  Only safety trip rollers or photo-electric cells can be used to stop the conveyor should excessive belt wander be encountered.  These should be set at least 10mm from the normal belt edge running position.
 

Rolled Baking Band

Conveyor Circuit Design Guidelines—Friction Driven

Typical Belt Circuit

Plain Roller Infeed & Discharge


Diameter of Infeed & Discharge rollers are typically 800mm dia. but can be as large as 1500mm depending upon the application.  Contact Wire Belt Technical Sales for advice.

Free Rotating Plain Roller at Infeed (Gravity Weight Actuated Tensioning)



NOTE: If you wish to use an alternative belt circuit then please contact Wire Belt Technical Sales to discuss your options.

Suggested Infeed Roller Take-up Systems

Note:  Where the belt take-up operates automatically (gravity/pneumatic/spring operated) you should ensure that the amount of take-up roller adjustment is the same on each belt edge. This can be designed into the system by using a rack & pinion or chain & sprocket arrangement (see below) that act evenly at the take-up roller position, or similar.















Gravity weighted chain sprocket arrangement (sprockets keyed to shaft).

Note:  If using independent manual screw adjustment then ensure that adjustment is the same on each side.

Belt Support—Carry Way

Multiple Free Rotating Roller Belt Support


Note:  All support rollers should be free to rotate and set horizontally and perpendicular to the centre line of the conveyor / belt.  The roller spacing should be sufficiently close to ensure that the belt lies flat without the need for increased belt tension.  The roller diameters normally vary between 75mm and 150mm dependent upon on the width of the belt and the mesh size.  They should have sufficient diameter to suit the width of the belt and application without deflection.

Chevron Pattern Wear Strips

Straight In-line Staggered Wear Strips



Notes:-
1) Ensure adequate clearance between the belt edge and any frame construction to prevent belt edge contact during use.
 
2) It is recommended that all wear strip surfaces are faced with low friction material where possible.

Belt Support—Return Way


All support rollers should be free to rotate and set horizontally and perpendicular to the centre line of the conveyor / belt.  The spacing can vary between 900mm and 3mtrs, however to limit the catenary belt sag between rollers and belt tension minimise the spacing. The catenary belt sag between rollers also acts as a natural belt take-up mechanism.

Suggested roller mounting:  One end to have a pillow block bearing placed on vertical plane with the other end placed in a horizontal plane – both to be adjustable using slots in the conveyor frame structure.  This allows the rollers to be adjustable in both vertical and horizontal planes to ensure true alignment of the rollers and the ability to adjust the rollers as necessary to track the belt. For belt tracking procedure refer to the “Tracking of Friction Driven Mesh Belts” within the Support Info tab.

It is also possible to use a combination of chevron/straight wear strips & free to rotate rollers however you should ensure that there is enough length at the infeed underside and carry way discharge to accommodate the tracking adjustment rollers.

Roller Guidelines

Drive & Idle Infeed Roller

These should be of plain parallel design without edge flanges and have an overall minimum width of:-  Belt width +200mm

The diameter of these rollers are typically 800mm but can be as large as 1500mm depending upon the application.  Contact Wire Belt Technical Sales for advice.
These rollers should be as large as practically possible which will maximise the belt contact with the rollers.  This in turn will minimise the necessary belt tension to maintain a non-slip drive.  Low belt tension will prolong belt life.  This will also create a more positive belt tracking arrangement.

Belt Support Rollers

These should be of plain parallel design without edge flanges and have an overall minimum width as follows:-  Belt width +200mm

In general diameters vary between 75mm and 150mm.  However they should have sufficient diameter to suit the width of the belt and application without deflection. 
 
With the exception of the drive and Infeed roller the minimum suggested diameter of rollers under tension with at least 30° of contact wrap is 300 mm.

Roller Limitations

  • The roller diameters above are suggested only to prevent damage to the belt and do not necessarily indicate the diameter for proper belt drive in terms of the application.  Contact Wire Belt Technical Sales for a full assessment of your proposed conveyor application.
  • Always maximise the roller diameters where possible to ensure the best performance from the belt.
  • Do not use flanged rollers in any part of the belt circuit as a means of belt tracking.  The belt will climb the flanges and cause permanent belt edge damage.
  • Do not use crowned rollers as this will stretch the belt centre causing permanent damage.
  • Please contact Wire Belt Technical Sales to confirm the appropriate roller sizes to suit your application.

Roller Material

  • Steel
  • Steel with high friction material – brake lining materials or similar.
  • Steel with rubber, neoprene or similar lagging material having a shore hardness of ≈60 and to suit maximum operating temperature of system.

Conveyor Frame Construction

  • Do not allow sharp framework parts to come into contact with the edges of the belt.
  • Ensure adequate clearance between the edges of the belt and any near framework parts.  As a general rule the longer the conveyor the greater the clearance needs to be.
  • Ensure all rollers are horizontally set and at 90° to the line of travel prior to tracking the belt.
  • Do not track the belt with static edge guides.  Tracking is achieved by adjustment of the belt support rollers – see “Tracking of Friction Driven Mesh Belts” within the Support Info tab of the website.
  • Any bed support for the belt should also be horizontally set with the surface aligning with the surface of the adjacent roller(s), or lower.
  • Always taper down the leading edges of any belt support wear strips/bed.
If in any doubt please contact Wire Belt Technical Sales Team.
 

Rolled Baking Band

Belt Installation Guidelines

In general conveyor circuits for Rolled Baking Belt consist of large friction drive discharge and idle infeed end rollers.  Support of the belt is normally over spaced free rotating rollers and grid support wear strips – dependent upon product and process. The belt installation requires careful planning in order that the procedures are undertaken correctly and that the belt will run smooth and efficiently in use.

There are two types of belt installation to consider:
  1. An EXISTING oven where the belt requires replacement after a period of use.  Click here to download instructions.
  2. A NEW oven installation with the belt being fitted for the first time.  Click here to download instructions
Should you require assistance during this process then please contact Wire Belt Technical Sales Team.
 

Rolled Baking Band

Preventative Maintenance Instructions

Whatever your normal preventative maintenance schedule may be for your equipment we strongly recommend that you carry out checks on the condition, operation and running of your Rolled Oven Belt on a daily or weekly basis, dependent upon the process situation.

With the belt completely free of product eliminate all residues or sticky deposits on both the belt or on rollers and surfaces that come into contact with the belt.  The cleaning can be by brushing, hot water, steam or other cleaning products that will not damage the belt.  Compressed air can be used to blow away debris in situations where liquid cleaners cannot be used.  But at all times ensure you work within your company health and safety standards.

In certain situations raising the temperature of the oven to burn off deposits may also be considered but care should be exercised to limit this temperature to prevent belt distortion and damage.
 
Check the condition of the woven edges of the belt.  If there is damage or breaks repair the belt to be similar to the remainder of the belt.  Check that the wire loop edges are made good.  Then check the belt circuit to establish the cause of the damage.  If parts of the conveyor structure have come loose and/or moved then re-fix the part to clear the belt.

Always ensure that the lateral control limit switches or photo-electric cells are in good working order.  The action of these could prevent serious damage to the belt in the event of a sudden side shift of the belt.
 
A mesh belt is an expensive component, which serves a needed purpose and its stoppage whether due to an accident or damage which cannot be repaired may have serious implications to production.
 
It is recommended that checks on the belt are carried out daily or weekly and particularly when a product change happens.
 
Please contact Wire Belt Technical Sales Team if you require further assistance.
 

Rolled Baking Band

Mesh Joining Instructions

Please note that the belt may be supplied in more than one case so you may have to make multiple belt joins.  Refer to the “Installation Guidelines” for information as to the correct position of belt joins for both fitting and adjusting to length.

The general joining instructions are as follows:
  • Pull the belt ends together and hold in position.  This can be done with the temporary use of cable ties or wire.
  •  If the belt requires length reduction then cut equal amounts from each end of the final pre-marked belt join.
  • You should note that the belt join requires 2 coil strands as the belt structure is of a duplex coil construction.  Spare joining coils are supplied with each belt order.
  • Insert the first coil by rotating it through both ends of the belt as shown in picture 1 until the coil protrudes through both belt edges.
  • Then insert by rotating the second coil through the alternate coil pitch space until it also protrudes through both belt edges.  See picture 2
  • Now release any cable or wire ties and drive belt slowly to position the join at either a rigid cross member or a terminal drum.
  • When in position gently hammer the coils flat to match remaining mesh.
  • Then cut and loop the wire ends to match the edges of the belt.
  • Re-check the join to ensure a flat even finish.
Note:  If at any time an offset at the belt join is noted then this should be corrected as per the “Straight Belt Adjustment” instructions.

Rolled Baking Band

Start-up and Test Running Instructions

After the belt has been installed in accordance with the “Installation Guidelines” then the following procedure for start-up & test running should be adopted:-

1) Cold Testing:
  • Check that the edges of the belt are clear of any part of the oven conveyor structure and that there is no foreign material or debris present that would interfere with the running of the belt.
  • Adjust the belt take-up mechanisms to action an even tension on the belt.  Do not over tension the belt.
  • Switch on conveyor and run at low speed (minimum) checking the drive drum end to ensure non-slip driving.  If the belt is slipping on the drive drum gradually increase the belt tension until no slippage occurs.
  • If the belt tracks off to one side at either the drive or infeed end then adjust the tracking support rollers by the method as shown in the “Tracking of Friction Driven Mesh Belts” document.  In general it will take 2-3 complete belt circuit revolutions for the belt to settle in a position.
  • Once the belt settles in to a true running position gradually increase speed until full operating speed is achieved.  In this process constantly check for tracking and position throughout the full circuit belt length.  Ensure the belt does not slip on the drive drum.
  • Occasional belt vibration may occur.  If present gradually increase the belt tension until it stops.
2) Hot Testing:
  • When the belt is stabilised under cold running conditions gradually increase the operating temperature in steps of 50°C from 150°C until the operating temperature is achieved.  Allow the belt to run for approximately 20 minutes at each temperature point.   Do not exceed a rate of 170°C per hour in this hot testing belt running operation.    
  • During this operation constantly check for tracking and position throughout the full belt circuit.  If adjustment is required then refer once again to the “Tracking of Friction Driven Mesh Belts” document.
3) Belt Cleaning:
  • After the testing phases are complete leave the belt running for several hours periodically checking for belt tracking and drive. 
  • Then brush and wipe down the belt before starting tests under load.
NB:  If you intend to adopt belt cleaning by carburising of food deposits then continue this process until the carburisation temperature (~350°C) is achieved.  Afterwards bring the belt down in the same steps and rate to the required operating temperature.

4) Starting the conveyor under load
  • After completion of the above procedures the installation can then be started up under full load conditions.
  • If during production there is sideways shift to the belt check that the oven heating is regular and even across the full belt width.  Uneven heating can cause expansion of the belt on one side which will result in uneven tension across the width and a sideways movement of the belt.
  • Side shift of the belt during operation can also be the result of abnormal load and distribution across the width.
NOTE: 
a.If at any time during the above test running phases the belt tension adjuster extends to its maximum position then it may be necessary to shorten the belt to ensure correct non-slip drive.  Refer to the “Installation Guidelines” and “Mesh Joining Instructions”.
b.Should the conveyor require increased friction drive then consider applying FERRODO (brake drum lining material) plates or similar to the drive roller.
c.If the oven conveyor is fitted with a lower return band scraper blade this must be fitted as close as possible to the drive roller and be across the full belt width without interfering with the belt edges.  These in general should be of a suitable plastic, wood or material that will not damage the belt.
 

Rolled Baking Band

Trouble Shooting Guide

Problem Possible Cause(s) Solution(s)
Belt not tracking properly
  • Product debris build up on rollers or support wear strips
  • Check all rollers and belt support surfaces for debris build up and remove
  • Drive & Idle Infeed rollers not set parallel to each other and 90° to conveyor centre line
  • Adjust Infeed and drive roller so that they are at 90° to conveyor centre line. Do not track belt by adjusting end rollers.  These must be set parallel to each other.  See “Tracking of Friction Driven Meshes” guidelines
  • Belt support rollers not set level and at 90° to conveyor centre line
  • Adjust belt support rollers to be level and at 90° to the conveyor centre line. Return side tracking rollers can then be adjusted horizontally to track belt as per “Tracking of Friction Driven Meshes” guidelines
  • Infeed roller belt tension/length adjustment rollers are not set to be equal on both sides (must be at 90° to conveyor centre line)
  • Ensure that infeed belt length adjustment roller is adjusted equally both sides of the conveyor
  • Uneven loading of product
  • Check pattern of loading across width and adjust to give uniform loading
  • Uneven temperature across belt in hot process
  • Uneven temperature across width will cause uneven belt expansion.  This will impact on the drive tension across the width of the belt.  Adjust heaters to give even temperature pattern
  • Belt stretched on edge
  • If belt is stretched on one edge then the belt should be replaced.  As a short-term measure (to continue production) consider flipping over every metre of the affected area of belting to help balance out the stretch on one side.  With belt lengths in general being 100m+ in length you should consider carefully whether to adopt this practice as it would require multiple joins in the belt.  Please remember this is only temporary as the belt has been damaged
  • Original fitting sequence of belt lengths not in order of numbered boxes
  • It is important that when fitting the belt lengths to the oven that they are fitted in box number order.  This ensures that the number of coils across the width match at the join position.  See “Rolled Baking Band Installation Guidelines”
Note:  It is normal to expect that each belt supplied will track differently to the previous belt.  Refer to the “Tracking of Friction Driven Meshes” guidelines when fitting a new belt  
Belt runs to one side
  • Drive & Idle rollers not set parallel to each other and 90° to conveyor centre line
  • Belt support rollers not set level and at 90° to conveyor centre line
  • Track belt according to the “Tracking of Friction Driven Meshes”
  • This could be by over tensioning on one side, heating imbalance across width, non-uniform loading of product or belt damage in use
  • To correct this run off condition it will be necessary to correct the straightness of the belt.  This can be done as shown in the “Straight Belt Adjustment Instructions”.  This procedure may have to be performed at various points in the length of the belt depending upon the severity of the belt run off
Belt Runout Note:  There will be some natural wander of the belt over both the drive & idle infeed roller which is due to the slight manufacturing variations in wire formation and tensile.  This is normal and should not exceed 25mm of total travel across the roller.  Therefore, ensure that all rollers & supports are in the order of 75mm to 100mm wider than the belt  
Belt slips on drive roller
  • Conveyor too long for belt specification
  • Load too heavy for belt specification
  • Operating temperature too high for belt specification
  • Check with Wire Belt Company Technical Sales with full description of application
  • Drive roller too small for the application to create enough contact friction drive
  • Consider increasing the terminal end drive and idle shaft drum rollers
  • Lagging existing roller with a high friction temperature resistant material such as Ferrodo brake drum lining material
  • High friction between belt and wear strips/support rollers
  • Reduce the friction between wear strips and the belt by using an alternative wear strip material
  • Check all belt support rollers that they are free rotating
  • Low or inconsistent belt tension
  • Check operation of infeed tension/belt length adjustment roller mechanism and correct any operational defects
  • Drive press roller (if fitted) does not exert enough pressure trapping the belt to the drive roller to maintain smooth drive operation
  • Increase press roller pressure against belt until smooth belt drive is achieved
  • Ensure press roller operates parallel to the drive roller it is working against
  • Automatic belt take-up is stuck and failing to exert constant tension to belt
  • Check the operation of belt take-up unit and ensure it is free to operate equally on both sides of the conveyor
  • Belt take-up roller is at the end of its travel creating slack in the belt
  • Remove a section of belt, adjust take-up and reconnect the belt ends.  Refer to “Mesh Joining Instructions” for correct procedure
Curve to wire strands across width or Convex/Concave belt camber
  • Belt drag on one edge or position across belt width
  • Check for uneven friction across width. It could be a rough wear strip, catching edge, product build up on rollers, uneven temperature across width, etc.  There are many causes so a thorough investigation of the belt circuit and process is necessary.  Contact Wire Belt Company Technical Sales if you are unable to locate and clear the problem.
  • Belt mesh worn
  • Inspect belt thoroughly particularly on its underside and replace belt if wear is excessive.  Belt can be turned over if wear is not too excessive
  • Uneven pressure of belt on drive roller if conveyor is fitted with a drive press roller
  • Check and adjust drive pressure roller so that it is acting parallel and with even pressure across the width of mesh on the drive roller
  • Temperature difference across belt is greater than 12°C
  • Reset heat distribution pattern and check for ingress of cool air into the operating environment
Rapid belt wear
  • Belt slips on drive roller – see above.
  • Support wear strips have sharp edges in contact with belt
  • Remove all wear strip sharp edges to present a smooth surface for belt to run over.  There should be no abrupt corners or edges of the support structure to impede smooth belt operation
  • Surface level of carry way belt support wear strips are set too high in relation to the belt underside level as it exits the infeed roller or discharges to the outfeed roller
  • The surface level of the carry way wear strips should be adjusted to the level of the infeed & discharge belt support rollers
Distortion of belt
  • Wear to belt support rollers
  • Check and replace any rollers that are worn and uneven across width
  • Product debris build up on rollers or belt support members
  • Remove all debris and fit constantly operating scraper to any driven roller if debris build up persists
  • Rollers are crowned
  • All rollers must be straight & parallel (not crowned). 
Damage to belt mesh
  • Support wear strips have sharp edges
  • Remove all wear strip sharp edges to present a smooth surface for belt to run over
  • Oven belt catching against infeed product loading conveyor
  • Check for damage to both loading conveyor & oven belts - action repair.  Set loading conveyor to give adequate clearance to oven belt
  • Discharge product scraper blade set too close to oven belt causing damage to oven belt (particularly the belt edges) & scraper blade.
  • Discharge scraper blade damaged
  • Check for damage to both discharge scraper blade & oven belt - action any repair to both.  Set scraper blade to give adequate clearance to oven belt.  Consider making the scraper blade in sections to reduce likelihood of total belt width damage to both belt & blade
Belt edge damage
  • Belt has wandered to one edge and is contacting the conveyor frame
  • See above for “Belt not tracking properly” & “Belt runs to one side”
  • Belt may have come into contact with edge tracking rollers, guide frame, infeed loading conveyor or discharge product scraper blade
  • It is recommended that edge belt guides do not interfere with the smooth operation of the belt.  They should only be used to actuate an emergency stop function of the conveyor belt if the belt tracks off to one side greater than the normal limits.  Check clearances between oven belt, infeed loading conveyor and discharge scraper blade.  Reset as necessary – see “Damage to belt mesh” above,
 
Belt corroding prematurely
 
  • Operating atmosphere or temperature not suited to belt specification
  • Consult with Wire Belt Company Technical Sales with full details of process application
Belt vibration
  • Belt passing over either rough or uneven surfaces or obstructions such as an angle, wear strip edge, etc 
  • Check complete belt circuit and remove any rough or uneven surfaces or obstructions
  • Incorrect belt tension
  • Adjust belt take-up to either increase or reduce belt tension and note any change in vibration
Belt surging on carry way infeed
  • Belt tension too high or too low
  • Trial the increase or decrease of belt tension and note if belt surging stops
  • Bearing failure of any of the rollers within the belt circuit that are in contact with the belt
  • Check all bearings are free rotating and not damaged.  Replace as necessary
Excessive belt stretch
  • Product load too heavy for belt specification
  • Friction between belt and support rollers & wear strips too high
  • Operating temperature too high for belt specification and/or belt material.
  • Consult with Wire Belt Company Technical Sales to reassess application and belt details.
Black debris build up on belt and conveyor frame structure
  • Normally occurs in the belt “Break In” phase of installation
  • As new all wire of the belt mesh and wear support surfaces have microscopic peaks at the surfaces. This black debris is caused by the peaks of these surfaces rubbing against each other in operation until they become polished and “seat in”. After the “Break In” phase of the belt the system should be thoroughly cleaned.  This process may have to be repeated before this black debris is reduced to an acceptable minimum

Tracking of Friction Driven Mesh Belts

Belt track off is one of the major causes of belt failure. Incorrect tracking will lead to edge damage and early failure of the belt.
 
The recognised principle is that a friction driven belt will always track perpendicular to the roller over which it passes.  This principle holds good for all rollers in the system.
 
The conveyor should be set up to run with all rollers parallel and level to each other. 
  • As a general rule if the end rollers are not parallel the belt will track off to the short side.
  • Make sure all support beds are level and symmetrical about the centre line of the conveyor.
  • Ensure that the conveyor framework runs straight between the idle infeed and the discharge (drive) roller.
  • Ensure belt support surfaces are free from obstructions (e.g. protruding framework)
  • Do not use crowned rollers to support or drive the belt at any position in the circuit.

Caution: Incorrect installation may result in permanent damage to your belt.

Before installing the belt it is important that the conveyor structure is set up as per the above instructions in a proper aligned and level condition.
 
For belt installation please refer to the “Installation Guidelines”.  Once the belt is installed and set to run in the slow speed mode careful attention should be paid to ensure straight tracking of the belt.  If the belt tracks off to one edge then the following procedure for true tracking should be used which generally means adjusting horizontally the position of the belt support rollers.

During the procedure of belt tracking DO NOT alter the end roller positions once they have been checked and set according to the instructions above.  It is important that they run parallel and level.
 
The following are guidelines for the proper tracking of woven steel beltings: 
  1. To check for proper tracking first mark the belt at several positions down the length at an equal position in from the edge of the belt.  The edge of the belt can also be used if free and clear of any covers or guards. 
  2. The belt should now be run for several complete revolutions at slow speed to allow for settling out of the belt to its running position.  Once the belt has settled to position then measure any track off by means of the belt mark or belt edge relative to a point on the conveyor frame at the infeed end.  This will then indicate the direction and amount of belt track off. 
  3. To adjust the belt tracking please refer to the sketch below and adjust the return support rollers as per indicated in the instructions. 
  4. As a general guideline the roller closest to the infeed should be set at approximately 1¾ times the belt width away from the idle infeed roller.   Adjusting this roller may be sufficient however if you need additional tracking then adjust each roller in turn working away from the infeed.  TIP:  For large amounts of belt tracking correction it is more effective to move many rollers a small amount rather than say one or two rollers a large amount.  If the conveyor has a full wrap snub roller in the return way then adjustment of that roller may be more effective as the full wrap of belt on this roller will produce more lateral belt movement for any given amount of adjustment.
  5. At each stage of adjustment check the lateral belt movement against the previously set reference point at the infeed.  Once the belt lateral movement is stable the belt is then tracked and the rollers should be firmly secured in position.
  6. As final check move to the discharge and check for any lateral belt movement.  If there is movement of the belt at this point then adjust any carry way rollers in a similar fashion to previously.  Adjusting rollers closest to the discharge first and then moving back down the conveyor if further adjustment is required.  In general however if the belt is supported on a symmetrical chevron pattern of wear strips then the belt should self-track at the discharge.
Various other methods of belt tracking can be used under limited circumstances:-
  • Steel angle edge plates, which may be faced with low friction plastic contact surfaces. 
  • Vertical edge rollers.  These have only a single point of contact with the belt and should be used in multiples to help alleviate high pressure contact on the belt edge.
  • Hyperbolic edge rollers which offer a straight line of contact with the belt edge over the length of the roller when set at the designed angle of operation.
 
 
Any of the above can be used as a temporary measure until the belt can be re-tracked as described in the main text above.  They can also be used where the normal method of tracking is not possible or the conveyor is short with light loading, low tension and low speed.
 
There are 6 golden rules when tracking the belt:
  1. Always operate the belt with minimum of belt tension to ensure slip free drive.
  2. Always operate the belt with the minimum belt speed.
  3. Do NOT push the belt edges with excessive force to guide the belt. 
  4. Any type of belt tracking should start at the point of least belt tension.  Normally at the infeed end return way.
  5. Under no circumstances should flanged or crowned rollers be used in an attempt to track the belt.  Both will permanently damage the belt.
  6. The starting point for any edge guides should be no closer than 2 x the belt width from either the drive or infeed idle roller or any other roller where the belt contact is in excess of 30°.
Note:  For Rolled Baking Bands edge roller or guides are NOT recommended.  Only safety trip rollers or photo-electric cells can be used to stop the conveyor should excessive belt wander be encountered.  These should be set at least 10mm from the normal belt edge running position.
 

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