Drive Pulley Lagging
typical problem faced during monsoon when water mixed with fine cargo creat a slippery surface on the lagging. this result in change in design condition which cause slippage.we have not foundany scraper which completely eliminate the problem. ■
Belt Lagging/Scraper
S.M Umarye, Sganesh,
Check out the Bearwhip belt cleaner and tell them leon sent you. ■
Re: Belt Lagging/Scraper
Originally posted by lzaharis
Check out the Bearwhip belt cleaner and tell them leon sent you.
Leon
Are you pushing for Dick now also. hahahaha
Gary ■
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.
Re: Drive Pulley Lagging
Its ideal to use a Diamond groved Rubber Pulley for drive. When Herring bone grove is used the direction of the grove should be chosen carefully to see that water squeezed out by the belt is flowing out wards.
The Hardness of the Rubber should be 3-5 Degrees lower than the belt hardness so that the Belt bites into the Rubber easily. If the hardness of the Rubber is more than the Belt, slippage will be more. Steel cord Belts normally have more hardness and greater tension than fabric belts and for such pulleys the lagging rubber should be of higher hardness 65-68 A and also wear resistant.
The friction coefficient of the lagged rubber surface can be kept higher using a silica filler in place of Carbon black.
The depth and width of the grooves can also be made bigger in problem ares ■
Re: Drive Pulley Lagging
We have eliminated slippage problem in few conveyors by using cermic alagging. But some conveyor suppliers are simply refusing to have the ceramic lagged drive pulley.
Can I have the comments of experts? ■
Re: Drive Pulley Lagging
profiled ceramic chips bonded on Rubber is used now to improve the friction in Drive pulleys. Ceramic because of its high hardness abd abrasive nature can wear the Belt cover faster and so the belt manufacturers will not like this.
Rajagopal ■
Re: Drive Pulley Lagging
Originally posted by S.M. Umarye
typical problem faced during monsoon when water mixed with fine cargo creat a slippery surface on the lagging. this result in change in design condition which cause slippage.we have not foundany scraper which completely eliminate the problem.
If there was such a scraper; where would it reside?
Sorry; the design condition does not change. Maybe it is erroneous but it does not change. If the operating condition is not covered by the design then the design is inadequate. That's basic engineering.
Tension, tension; my kingdom for Euler. There is another always overlooked variable in the Law. Increase the wrap in the wet. Pack the snub drum up. Too easy by far. With good lagging it will work a treat. ■
Re: Drive Pulley Lagging
I remember that experts are against using drive snub pulleys.
I also agree with them.
https://forum.bulk-online.com/showth...snub#post25933 ■
Re: Drive Pulley Lagging
Agree all you want. Then look at how many conveyors are fitted with snub drums. If you don't fit a snub then don't winge when the belt slips. For a belt to slip there are two variables involved: Mu & Theta. Tensions are slightly irrelevant because if you have slip then you don't have correct drive whatever your load. If the designer selects the wrong Mu it will give a wrong Theta requirement. Carry on.
I would still like to know where the mystic lagging cleaner sits. Similarly if you know how to increase the wrap without a snub drum the forum members would be very interested to learn.
Snub drums are considered as evil necessities: until you have a belt slipping in the wet: most probable on any outdoor installation.
The contracts engineer for one of my erstwhile employers held out that they (not me: I was thousands of miles away) had used the Mu recommended by the Blue Book and so could not be held responsible for the yard belt slipping in a very rain sodden Somerset quarry. As if! ■
Re: Drive Pulley Lagging
Originally posted by Rajagopal
profiled ceramic chips bonded on Rubber is used now to improve the friction in Drive pulleys. Ceramic because of its high hardness abd abrasive nature can wear the Belt cover faster and so the belt manufacturers will not like this.
Rajagopal
https://forum.bulk-online.com/showth...ging#post39169
The references I am giving are to clear my doubts only.
I regret if any one get offended when I am giving the references. ■
Re: Drive Pulley Lagging
quote of Mr. Ganesh:
"We have eliminated slippage problem in few conveyors by using cermic alagging. But some conveyor suppliers are simply refusing to have the ceramic lagged drive pulley."
Dear Mr. Ganesh,
aren't you now some kind of expert yourself, as you use ceramic lagging etc. see above? What are YOUR experiences? It would also be of interest if you could give the arguments of the mentioned suppliers and full technical informations about the conveyors you upgraded (staus before/status after etc.).
At this place I would also request your kind feedback about the thread "broken adapter rings", you started this thread but did not yet report your results. Thank you!
Roland ■
Re: Drive Pulley Lagging
Thank you Mr.Roland,
The ceramic lagging what we provided in the conveyors are EP fabric belts. In all the conveyors are slippage problems are solved with good life. And we kept the speed sensor at higher margin level.
( For your informatioon, when I tried to search in our forum regarding ceramic lagging , there are about 50 threads. I read about 10 threads so far. Somebody advised not to use in Nylon belts and for the conveyors where the bottom cover thickness is less than 3 mm , which you may note.)
Yes, we faced problem in one conveyor, where the lagging was slightly uneven at drive pulley. Though immediately problem could not be predicted, after few weeks the conveyor was worn out at the bigger diameter area, due to the higher in velocity. After that uneven was rectified and full lagging done.
I tried a lot to convince the vertical conveyor supplier for providing the ceramic lagging. But they refused without reasons.
Since the conveyor is new and within warranty period I could not force them. This conveyor is 1400 mm steel cord vertical belt. So far this conveyor has not slipped in monsoon.
Since this is a public forum, I have not mentioned the supplier's name.
Regarding Adapter Sleeve Damage, I handed over the broken pieces to the bearing supplier on 10/10/2008 for their feed back after testing in their lab for RCFA. Though I followed up with 3 or 4 mails and personal calls, I did not get reply so far, may be due to festive season here.
I also feel morally responsible to let you know the findings also. ■
Re: Drive Pulley Lagging
Dear Mr. Ganesh,
thank you very much for your kind and detailed reply.
As far as I know ceramic lagging is advisable, if moisture and particles or so make up a slippery film between pulley surface and belt.
Normal moisture (I don't know the monsoon conditions in your place) must not lead to slippage of the belt, see the answers of the other collegues.
The use of ceramic lagging should not bring increased / critical wear on the belt, if properly applied. But here the manufacturer of the lagging must speak his word considering all influences.
Next step on the ladder towards slippage avoidance is the use of polyurethane lagging, but this demands machining of the primarily sprayed PU-lagging and (as far as I know) is restricted to slippage problems when conveying some special kinds of bulk materials.
Hope you find a useful hint herein.
Best regards
Roland ■
Re: Drive Pulley Lagging
Ceramic being harder and tougher than Rubber, wearing of rubber takes place when ceramic rubs with belt surface. To minimise the damage, the rubber in which the ceramic is embedded can be made softer and highly resilient.
PU lagging may not be a good option for the Hot humid conditions of India as Poly urethanes (particularly ester type) degenerate faster in hot humid conditions.
The friction co efficient Rubber surfaces for critical applications can be improved by compounding the Rubber suitably. Addition of Graphite and Precipitated Silica as partial replacement to Carbon black can improve the grip better.
Dusting the rubber surface with finely powdered rosin or other tackifying resins was found to improve the grip on the belt.
Rajagopal ■
Re: Drive Pulley Lagging
Dear Shri S. Ganesh,
Referring to your question I am giving only part reply.
The drive pulley lagging can have herringbone grooving or diamond grooving. In general herringbone grooving is preferred if the conveyor is running in one direction. The herringbone groove rubber lagging is relatively stronger. Generally one opts for diamond grooving for reversible conveyor. Well one can also use diamond grooving for unidirectional conveyor. This is general observation and possibly the aforesaid practice may have some relevance to the life of lagging.
While designing conveyor one has to see the operating condition between pulley surface and belt. DIN, ISO already mentions friction coefficient value to be considered between rubber belt and various types of lagging. One can use this coefficient and then conveyor is designed such that no slip should occur between belt and pulley, during steady running, starting and stoppage. That means take-up is designed such that it maintains the minimum tension for conveyor working.
Ishwar G. Mulani
Author of book : Engineering Science and Application Design for Belt Conveyors
Author of book : Belt Feeder Design and Hopper Bin Silo
Tel. No. : 0091 (0)20 2587 1916
Email : parimul@pn2.vsnl.net.in ■
Re: Drive Pulley Lagging
go to rematiptop.com and find theire ck-x lagging it is pricey bu it will sort out your problem ■
Pulley Lagging
Hi all,
Have someone experienced another profiles for pulley grooving? Other than diamond or hering bones?
Rgds ■
Pulley Lagging
Dear All:
how is the ceramic drive pulley? are there any large volume installed on site? how is the performence and realibility also with cost compare to common rubber lagging?
thanks ■
Re: Drive Pulley Lagging
Dear Shri S. Ganesh,
DIN / ISO mentions friction coefficient between belt and pulley surface in varied situation of the surface, such as dry, wet, contaminated with clay type of material in conjunction with nature of surface such as bare pulley, herringbone rubber lagging, ceramic lagging, etc.
The principle of the design is that during highest magnitude of tractive pull (such as starting) the belt should not slip on the pulley. For this slack side tension is taken of adequate magnitude so that T1 / T2 ratio always satisfies the no slip condition. This means if conveyor is correctly designed duly considering the application, belt will not slip. Belt slip is not allowed in the design (except as a very rare unexpected occurrence), because belt slip will result into faster wear of belt and lagging.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
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: parimul@pn2.vsnl.net.in ■
Re: Drive Pulley Lagging
Thank you Mr.Mulani,
1. After few years, I am noting that the drive pulley lagging become polished and hard ( though the grooves are still present ) and starts slipping. Should the shore hardness match with the conveyor belt bottom cover hardness? What is the tolerance?
2. I have removed drive snub pulleys in few conveyors after providing ceramic lagging for the drive pulleys. I like to know the design implications.
3. For very slow & small length conveyors like dozing and weigh feeders , I have seen that the drive pulleys are not lagged but having only finer machined grooves across the face width of the conveyors.
Request your expert opinions on the above points.
Thanks a lot & regards, ■
Alumina Ceramics, Zirconia Ceramics & Zta
Wear resistant ceramic lining – Alumina, zirconia & ZTA
Ceramic grinding media – alumina & zirconia
Steel & rubber backed ceramic plate
Pulley lagging
https://aluminaceramics.wordpress.com/ ■
Belt Snubbing At Drive Pulley
Hello,
The thread is quite old. Anyway I am putting some comment which may be beneficial for readers.
Installation of snub pulley can have following negative points:
- If material is wet and sticky, it will create dirty situation at snub pulley because such material sticking on the belt face will get squeezed, etc.
- In certain conveyors like a boom conveyor of a stacker reclaimer machine installing snub pulley will create some imbalance which is to be eliminated by additional counter weight; and also there is no proper space for installing snub pulley as it may hit the stockpile.
Ishwar G. Mulani
Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is DIN / ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world).
Author of Book: ‘Belt Feeder Design And Hopper Bin Silo’
High class computer aided design programs are available to the buyers, visit my website www.conveyor.ishwarmulani.com
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 ■
Drive pulley lagging
Dear all, What should be the method to check the drive pulley lagging? What should be it's hardness range? When will it start slipping ? Will it be possible to predict a conveyor slippage before rainy season? How to ensure the required tension of the belt?
Request answers for both for fabric and steelcord belts. ■