Re: Belt Sway In Inclined Conveyor - Garland Configuration
Well for starters garland idlers are not recommended on such a large incline and is the main reason for your woes.
Carry idlers are designed to be perpendicular to the frame. Gravity takes over with garlands on an incline and works on the same principle as idler tilt only in a much more exaggerated way which increases slip between the belt and the idlers causing the belt to mistrack. Idler tilt is not recommended to be over 2°.
I am afraid the only proper solution to your problem is to replace the garland with a rigid idler. If this is a new installation I would go back to the designer and asked why they used garlands in the first place. ■
Gary Blenkhorn
President - Bulk Handlng Technology Inc.
Email: garyblenkhorn@gmail.com
Linkedin Profile: http://www.linkedin.com/in/gary-blenkhorn-6286954b
Offering Conveyor Design Services, Conveyor Transfer Design Services and SolidWorks Design Services for equipment layouts.
Garlands On Incline Conveyors
Originally Posted by Gary Blenkhorn
Carry idlers are designed to be perpendicular to the frame. Gravity takes over with garlands on an incline and works on the same principle as idler tilt only in a much more exaggerated way which increases slip between the belt and the idlers causing the belt to mistrack. Idler tilt is not recommended to be over 2°.
I am afraid the only proper solution to your problem is to replace the garland with a rigid idler. If this is a new installation I would go back to the designer and asked why they used garlands in the first place.
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Dear Gary,
A slight correction - Idlers should be perpendicular to belt axis (frame is irrelevant).
You are incorrect for carry roller causing miss-tracking with Garland since the center roller swings forward (counter to belt travel) by gravity and thus acts similar to forward tilt of wing idler, which enhances tracking alignment. This is at penalty of power and wear.
Return garland rolls, on incline belts however, miss-track belt, since center swings by gravity forward in direction of belt travel. Also does wear on rollers and belt. Some remedies include trying back garland center pivots on return with light cables. Eventually, cables fatigue and break such as at Spring Creek OLC, Obed Marsh OLC, et. al.
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Generally, garlands should only be used on shiftable conveyors or when transporting very large lumps ( > 400 mm) when belt construction is on light side. ■
What Is Belt Sway???
I have seen a number of parties talk about belt sway. Please be specific in your detail of belt behavior.
Some refer belt sway as belt sag. Some refer to belt sway as belt oscillation. ■
Belt Sway??
Belt Sway Also = Idler Oscillation?? ■
Re: Belt Sway In Inclined Conveyor - Garland Configuration
Dear Sirs,
I assume that Mr.Paul is referring belt sway as belt is running off-track or not running at center.
If the picture posted is exactly same as the one installed at site, I think that the rubber rings are not allowing the conveyor to run at center, once it is off tracked.
Having less contact between rollers and belt also, may not help in rectification.
Regards, ■
Belt Sway ?? Garland ??
Originally Posted by Paul SamsonOne of Fuel Handling supplier had supplied Garland Idlers in Inclined belt conveyor .
Material Handled : Bagasse
Bulk Denisty : 150 Kg/cub. Mts
Conveyor Inclination : 18 deg
Capacity : 200 TPH
Belt Speed : 1.19 Mtr / sec
Now we are facing frequent belt sway on these conveyor
We are looking for the suitable solution to control the sway. We have used self aligned idlers on fixed frame troughed idler to control the sway. Any such arrangement is available for Garland idler configuration? Kindly let us know.
Illustration added by Administrator as an example:
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Dear Admin.
The chosen photo shows a off-center running belt supported by fixed frame idler not garland.
The thread started has not yet defined the meaning of belt sway. So some are at a loss as to what it means and how to address it.
The particular return idler, with rubber rings, illustrates a common problem with rubber rings that capture belt edge and belt mis-alignment restoration. Once mis-aligned = always mis-aligned. ■
Taking Note
Originally Posted by sganeshI assume that Mr.Paul is referring belt sway as belt is running off-track or not running at center.
If the picture posted is exactly same as the one installed at site, I think that the rubber rings are not allowing the conveyor to run at center, once it is off tracked.
Having less contact between rollers and belt also, may not help in rectification.
Regards,
You are correct again. The left hand disc is left untouched by the belt edge and by the pattern on the return side seems to have been out of touch for a long time.
I doubt the installation really matches the picture but it is still something I hadn't realised before. I've never considered disc return idlers...on the assumption that they look more expensive and perhaps wear furrows along the belt. ■
John Gateley johngateley@hotmail.com www.the-credible-bulk.com
Where's The Reason?
If sway understates mistracking, then the origin of this needs to be found.
Any issues with alignment of pulleys, off-center loading etc.?
At this capacity, pls. tell what take-up system is installed, and how did you check whether it is correctly aligned.
The picture shows a mistracking belt, and valuable comments have been made as to the downside of a rubber disc return idler. The upside I'm told should be that a rubber disc return idler supports the cleaning of the belts carrying side. But there should be only some of those in the return strand.
However, as the original post only states garland idlers & asks for a remedy, I'd assume garlands in the upper strand and also in the lower strand. Then, there is to my knowledge no self aligning belt track correcting device for garland idlers neither for upper nor for lower strand. Some control could be exercised by deliberately setting some garlands at an angle to the perpendicular nominal position. But this is at a price as pointed out earlier, and I do not know of a "proven technology method sheet" to point to.
Remedy the cause, and be it to come back to rigid idler design. If that is possible.
Out of interest, I'd also forward the same question as Gary: Why the change to garlands?
Regards
R.
P.S.:
Dear thread starter, it would be so nice, professional and also honoring the efforts of all involved to hear from you again. Or to learn something new. Thanks in advance for considering. ■
Re: Belt Sway In Inclined Conveyor - Garland Configuration
Dear All,
Thank you very much for your valuable reply.
We are refering " Belt sway" as basically belt mis tracking in Garland Idler configuration. Due to this belt sway, we are frequently facing material spillage from the conveyor and excessive wear & tear of Belt edges.
We have used three roll, 45 deg on the carrying side and two roll - 15 deg on the return side . As suggested in the forum, it is very difficult to provide the fix frame return Idlers. In the above case, is it advisiable to provide SA carrying & return Idlers to restrict the belt sway? ■
Re: Belt Sway In Inclined Conveyor - Garland Configuration
Dear Mr.Paul Samson,
Could you please post the photograph of this conveyor and General Arrangement ( GA ) drawing ? There could be many reasons for off-tracking.
If belt runs in center and causes spillage when conveying the material due to off-tracking, I suggest to ensure the center feeding of the conveyor.
Regards, ■
Writing On The Wall
Originally Posted by Paul SamsonThank you very much for your valuable reply.
We are refering " Belt sway" as basically belt mis tracking in Garland Idler configuration. Due to this belt sway, we are frequently facing material spillage from the conveyor and excessive wear & tear of Belt edges.
We have used three roll, 45 deg on the carrying side and two roll - 15 deg on the return side . As suggested in the forum, it is very difficult to provide the fix frame return Idlers. In the above case, is it advisiable to provide SA carrying & return Idlers to restrict the belt sway?
Is this just me?
Mr. Samson speaks in the lines of a "We are referring" etc. which in my understanding is official commercial wording indicating the involvement of a commercial entity in its legal function.
Now, the drift of the quoted reply is that "suggestions" have been made and "advice" is required. Whatever the input, however, up until now thoroughly all indication is avoided of a) design cause of change to garlands and of b) all technical causes for described belt mistracking.
Speaking for myself, I consider this forum a contact place of interested private individuals, who on a noncommercial and not legally binding base say their personal opinion about matters of their professional interest.
Legally and commercially valid suggestions and advice is subject to a legal, and paid, service contract.
Regards
R. ■
Belt Sway On Inclined Conv
QUOTE=Paul Samson;85070]Dear All,
Garland Idlers on the carrying side with plus inclination are always useful for alignment. Any de-inclination on carrying side will give belt misalignment. This being basic for forward tilt of Idler principle.
On return side it becomes de-inclination and with garland idlers on return side it will positively create belt misalignment. Normally , our experience has shown that on return side if de- inclination is more than 7 degrees, problem will be faced.
Pl fixed these garland idlers on return side by doing some modification on frame.
Subash- Formely system designengineer with TKI india ■
Re: Belt Sway In Inclined Conveyor - Garland Configuration
Hello,
Everyone knows that wheel rotation axis should be perpendicular to intending (required) motion of vehicle, or else wheel tends to steer it. In case of belt conveyor, the required direction of belt is fixed (along conveyor), so rollers axes should be at right angle to belt conveyor centre line. Little latitude for this is tolerable due to play at spindle-ends seating, and bearings clearance, which allow self correcting phenomenon, arising due to action and reaction.
In your case, the installation disregards above and, also general practice that garland idlers are not preferred beyond certain inclination, because they promote faster wear of belt and idlers, and can result into situation you are mentioning (which would be particularly aggravated for return run as pointed out by Mr. Nordell). You can think about following:
1) Replace return side idlers, by single roll type.
2) See if the situation becomes tolerable. If not, then replace carrying side idlers by fixed frame type. To reduce the expense you can use rollers (if clumsy correction of ends is acceptable) and mount them on trough type idler frame to reduce modification in conveyor frame.
It has been observed that sometimes inferior features creep in the plant because it is in ‘specification’ and nobody wants to bell the cat. Unfortunately nature’s law does not recognise such things. As a general comment, it is always beneficial not to ignore engineering-science rules, even though they do not speak for themselves.
Regards,
Ishwar G. Mulani
Author of Book: Engineering Science And Application Design For Belt Conveyors (new print November, 2012)
Author of Book: Belt Feeder Design And Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Pune, India.
Tel.: 0091 (0)20 25871916
Email: conveyor.ishwar.mulani@gmail.com
Website: www.conveyor.ishwarmulani.com ■
Mis-Alignment For Conveyor With Garland Idlers
Hi
basic concept- forward tilt in Idlers will make the belt to get aligned. A positive inclination in layout will make the belt aligned with garland rollers. A backward tilt will cause mis-algnment of belt. On return side with garland idlers, the situation is reverse , the garland idler will act as backward tilt and will cause mis alignment. Our experience garland idler when used on return side with angle more than 7 degrees cause belt misalignment. On return side use fixed idlers if inclination is more than 7 degrees.
The assumption in above statement is that all other conditions required for alignment are taken care.
Subash ■
Belt Sway in Inclined Conveyor - Garland configuration
Dear All members,
One of Fuel Handling supplier had supplied Garland Idlers in Inclined belt conveyor .
Material Handled : Bagasse
Bulk Denisty : 150 Kg/cub. Mts
Conveyor Inclination : 18 deg
Capacity : 200 TPH
Belt Speed : 1.19 Mtr / sec
Now we are facing frequent belt sway on these conveyor
We are looking for the suitable solution to control the sway. We have used self aligned idlers on fixed frame troughed idler to control the sway. Any such arrangement is available for Garland idler configuration? Kindly let us know.
Illustration added by Administrator as an example:
Garland idlers ■