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Thread: Yard Conveyor Belt Speed

  1. #1
    Author Guest

    Yard Conveyor Belt Speed

    Dear Sir,

    We would like to know the maximum permissible speed for carrying crushed limestone (-150 mm) on *yard conveyor ( 300-400 mtr) belt working in conjunction with Stacker for stacking Limestone. *The yard conveyor is 1200 mm wide.

    Best Regards,

    Shailesh R Dalwadi,
    Metso Minerals (Mumbai ) Pvt. Limited, Thane. India
    Tel : + 91 22 2545 2755
    Fax: + 91 22 2545 2760
    e mail : dalwadi.sr@metso.com

  2. Dear Shailesh Dalwadi,

    The limiting factor will be the speed and belt width of your stacker. You should not exceed the capacity of the stacker belt with that of your yard belt.

    Take the desired stacking tons per hour, calculate the speed required to achieve this with your stacker belt, then calculate the speed required to feed the stacker belt with your yard belt. Be careful to consider your transfer point, to avoid jamming and possible damage to the stacker belt. Also, ensure that the loading point for the yard belt is sufficient for your needs.

    Regards,
    Dave Miller
    ADM Consulting
    10668 Newbury Ave., N.W.,
    Uniontown, Ohio 44685 USA
    Tel: 001 330 265 5881
    FAX: 001 330 494 1704
    E-mail: admconsulting@cs.com

  3. Dear Mr. Dalwadi,

    You have mentioned maximum lump size as () 150 mm.
    I presume your specified 150mm is the maximum dimension of the lump in any one direction, as per usual definition.
    It is also presumed that the 90% of material is less than half the maximum size. That is 90% of material is less than 75 mm, as per usual definition of unsized material.

    For the above mentioned size distribution of the material, the allowable maximum dimension of lump is 450mm, for 1200mm belt. Thus, the maximum lump size is less than half the allowable maximum lump size.

    For the aforesaid sizing of material, the generally used maximum belt speed is 3.75 mps, for in-plant conveyors of 1200 mm belt, for handling of limestone.
    The belt speed is subjective issue and opinion can vary somewhat. Higher speed can be used for long distance (cross-country) conveyors.

    You need to use belt fabric and cover thickness to suit above speed and impact condition. The chute layout should also be complementary to material size, nature and speed. The boom conveyor will need thicker cover, and belt life (beyond warranty period) could be different for short conveyors and long conveyors in such system, which is to be accepted.

    Regards,
    Ishwar G Mulani.
    Author of Book : Engineering Science and Application Design for Belt Conveyor.
    Advisor / Consultant for Bulk Material Handling System & Issues.
    Email : parimul@pn2.vsnl.net.in
    Tel.: 0091 (0)20 5882916

  4. #4
    Lawrence K. Nordell

    Lawrence K. Nordell

    President and CEO

    Conveyor Dynamics Inc. [eDir]

    Conveyor Dynamics Inc.

    Professional Experience 58 Years / 8 Month Lawrence K. Nordell has 58 Years and 8 Month professional experience

    Discussions 2608 Lawrence K. Nordell acceded to 2608 discussions, Articles 0 Lawrence K. Nordell wrote 0 articles, Publications 0 Lawrence K. Nordell Nordell released 0 publications

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    Know-How Design (1521) Lawrence K. Nordell used this tag 1521 times, Pipe Conveyor (238) Lawrence K. Nordell used this tag 238 times, Chutes (119) Lawrence K. Nordell used this tag 119 times

    Another Thought:

    A yard belt, with a horizontal orientation, is speed limited by the following:

    1. Idler roll diameter and treatment of tolerances
    2. discharge chute design and plugging during an aborted stop
    3. oreintation of stacker position associated with point 2.
    4. belt wear life due to adverse loading chute design
    5. dust generation -- low dust means below 5 m/s belt speed
    6. area wind direction associated with point 5.
    7. noise generation
    8. idler spacing, belt construction and lump size considered together

    The belt can achieve a faster speed. Designer knowledge and general economic benefit would point toward a 4 m/s speed. I do know of yard belts running much faster carrying + 8000 t/h. The answer must be taken in context -- limited answer with limited data.

    Lawrence Nordell
    Conveyor Dynamics, Inc.
    www.conveyor-dynamics.com

  5. #5
    pelletman Guest
    Been just about 30 years in this business, starting out in mechanical conveying and PT/ . Industry still slow to change into metric. . tooling etc. I probably never will. I would certainly be interested in responding more if we'd communicate in one language, in any event, this is the forum and It's taken me 30 minutes to figure out what ya'll are talking about. . .Bottom line for maximun belt conveying belt speed in based on 1. The top carrying design or configuration of belt profile ie. flat, herringbone, zig zag etc., belt design PIW, dia. head and tail pulleys in regards to the type of mechanical belt fastner 2. The inlet feed opening and design for allowing the material to uniformly flow, eliminating impact & unnecessary dusting and allows the flow rate to settle or set onto the top of the conyeyor for transporting. 3. Horsepower.

    I have furnished and commissioned belts conveying at 1140 FPM with is considerably above, the previous referenced speeds of 700 to 787 FPM.

    In any event, you'll need to look at more & more horsepower and a larger sheave(s) on the motor or driver (OHL) and until you arrive at the max belt speed to convey ( I'd start by increasing drive train for an increase of 10% belt speed and monitor amp loading and hopefully de-regulate design of v-belts, better to smoke a few drive belts, than a motor) or in the case I sited, projecting from end of discharge head pulley 150 yards for open stockpiling, 48" and 60" Wide. 3/16" half moon belt cleats, flat back bottom and inclined. Once max. conveyor speed is established review the bearings and shafting requirement's on the head and tail pulley, together with the return idlers.

    I'd be interested to know, is it cost justifed for you to triple you horsepower and double your conveyor drive train design while having to replace a belt say twice (min) the amount and maintenance cost's quadraupled ( x4)?

  6. #6
    Lawrence K. Nordell

    Lawrence K. Nordell

    President and CEO

    Conveyor Dynamics Inc. [eDir]

    Conveyor Dynamics Inc.

    Professional Experience 58 Years / 8 Month Lawrence K. Nordell has 58 Years and 8 Month professional experience

    Discussions 2608 Lawrence K. Nordell acceded to 2608 discussions, Articles 0 Lawrence K. Nordell wrote 0 articles, Publications 0 Lawrence K. Nordell Nordell released 0 publications

    Searching nothing specified

    Know-How Design (1521) Lawrence K. Nordell used this tag 1521 times, Pipe Conveyor (238) Lawrence K. Nordell used this tag 238 times, Chutes (119) Lawrence K. Nordell used this tag 119 times

    Pelletman:

    Metric is good. Imperial is becomming the dinosaur. Your 1140 fpm is an agricultural 5.8 m/s. There are yard belts running over 6 m/s (1181 fpm) in many parts of the world for ship loading coal and iron ore.

    There are yard belts running up to 10 m/s (1969 fpm) if you allow cross-yard stacking.

    Bottom line for maximum speed usually is either transfer chute design and its implications, or dust. When dust is an issue then the upper limit is around 5 m/s for a P80 of 50 mm (+/-) and less for finer granular configurations to keep the Reynold's terminal settling velocity number within acceptable time limits for the nominated belt transport speed.

    The thread starter is, I believe, refering to horizontally profiled belts operating with stackers that have your bumps. Thus, types of surface bumps are not normally considered or relevant for the yard belts.

    You are correct about increased speed requires more power. However, I am a non-believer: a) 3 fold power increase is possible or, b) 2-fold power increase or, c) any such large number. The big number is parasitic losses (idler and pulley seal drag, scrapers, et al. ) that increase linearly with increased speed. The speed increase does reduce the crossectional area needed and may allow a reduction in belt and idler width with is consequential cost savings. Where is the optimum?

    Another bit: belt life is, in part, caused by belt speed and transfer chute design. Today, transfer chute designs can yield a belt life well beyond 15 years. Speed becomes less relevant and can be increase well beyond old practices if you know how to design the correct chute geometry. This can not be taken in isolation. There are other arguements that may control the design.

    Conveyorman

  7. yard speed

    We run our belts OK - 1200mm at 3.2m/sec for limestone/clay and high grade limestone.

    Your could go sloightly faster but I would not recc. it.

    The main issue would be the stacker transfer and boom belt...esp. if the stacker is layer forming. This is where we have problems esp. in wet weather and belt cover wear.


    James Morrish
    Australia

  8. #8
    Lawrence K. Nordell

    Lawrence K. Nordell

    President and CEO

    Conveyor Dynamics Inc. [eDir]

    Conveyor Dynamics Inc.

    Professional Experience 58 Years / 8 Month Lawrence K. Nordell has 58 Years and 8 Month professional experience

    Discussions 2608 Lawrence K. Nordell acceded to 2608 discussions, Articles 0 Lawrence K. Nordell wrote 0 articles, Publications 0 Lawrence K. Nordell Nordell released 0 publications

    Searching nothing specified

    Know-How Design (1521) Lawrence K. Nordell used this tag 1521 times, Pipe Conveyor (238) Lawrence K. Nordell used this tag 238 times, Chutes (119) Lawrence K. Nordell used this tag 119 times

    James,

    You speak of speed restrictions, with belts > 3.2m/s, at the stacker transfer boom due to?

    Wet weather refers to sticky ore?

    Belt wear refers to ore slippage on the belt?

    Limestone/clay verses other products, such as the red mud field, is the problem maintenance, technology, .... ?

    I would think that, aside from the high speed stacker and its right angle and sloped transfer, the transfer physics is the same for large and small conveyors, short and long conveyors, big and little capacities.

    We see in Australia, Alcoa running better than 7 m/s and transfering well with red mud (sticky, fine particle size, .....

    From these points I would ask you to elaborate on your experience and attempts to do better. Is cost an issue? Technical understanding an issue?

    Lawrence Nordell
    Conveyor Dynamics, Inc.

  9. Hi,

    We had a packaged stacker/reclaimer.

    Hence, for minimum tender cost, U get a lightweight, short stacker with low transfer heights etc.

    The stacker is on the raw materails side of the cement plant - it is a blending stacker...boom conv. lenght is only 25m, hence, cycle time is very short.

    Hence, handles, high grade limestone, limestone/clay (low mix).

    We handle 3Mt pa of raw materials

    The apparent material speed into the tripper car varies considerabley depending on the stacker direction...the trajectory is effected also

    The stacker will be slewing soon.

    Hence, transfer to the boom conveyor is an issue - the material trajectory, the carryback (45o chute angle, less on the valley), boom conv. belt wear, belt tracking etc.

    The clay when wet is very sticky - is is not well mixed, hence, get problems in the poor transfer point.

    We tried feed point deflectors but these are sensitive to bottom buildup > blockage....

    We have a curved discharge point chute > had to get get the material to change direction to vertical about 400mm after the pulley!!!

    Boom conveyor mis tracking is an issue when wet , less so when dry.

    A proper stacker transfer would mean more height/distance > this means larger drive on the yard belt etc. I would also go for a wider and slower boom conveyor > less wear rate plus try to get all the material sitting on the bottom of the trough > less tendency to mis track.

    I am not against high speed belts but U need to consider the total application.

    Cheers


    James

  10. Yard conveyor belt speed

    Dear Mr. Shailesh,
    Belt speed depends on material characteristic,lumpsize factor & abrasiveness factors.Considering the all factors the max. speed should not be more than 2.8m/s for 1200mm belt width.I want to restrict to max. of 2.5m/s.If it is from mining application only ,speed can be increased slightly.More speed above this will cause degradation of LS.
    Regards.
    A.Banerjee

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