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Thread: Looking for Power and effort calculation manual for Steep Angle Conveyor / sidewall

  1. #1
    Join Date
    Aug 07
    Posts
    37

    Looking for Power and effort calculation manual for Steep Angle Conveyor / sidewall

    Hello everyone, i'm looking for power and effort calculation manual for Steep Angle Conveyor / sidewall

    I hope to be in the correct group otherwise please indicate to me which is the most suitable group

    Where can I find a manual with the formulas for the calculation of the power and strain for "Z" shaped belt conveyors?

  2. Hello,

    The reader is to acquaint himself about the application, use and constructional aspects of steep angle conveyor from the relevant literature by the belt manufacturers and manufacturers of such conveyor. Here, it is understood that the reader is already familiar about such conveyors.

    This reply deals with the following two main issues:
    1) Steep angle conveyor sizing i.e. deciding the belt width, pocket width, speed, etc..

    2) Calculation of resistances which are input for calculation of belt tension and power.

    Conveyor sizing :
    The belt conveyor capacity is calculated in a manner similar to bucket elevator i.e. material contained in each pocket. The pocket is formed by belt flat upper surface, 2 side walls and cleat/s, as against one bucket. The number of pockets discharged per hour is (Velocity v mps) x 3600 Divided by (Cleat spacing in metre).

    The hourly discharge rate mtph = (Material weight kg in one pocket) x (Number of pockets discharged in one hour) Divided by 1000.
    This value should be equal or greater than the required design capacity.

    As for the material contained in one pocket, refer the sketch attached with this post reply at the end. The material volume contained in one pocket is the shown cross section area multiplied by the length of the cleat. Convert this into material mass kg in one pocket, by multiplying it with bulk density. The angle ‘beta’ is surcharge angle of the material, which could be say around 20 degree, etc. as applicable for belt conveyors. The angle ‘delta’ is conveyor inclination to horizontal.
    The aforesaid sizing procedure (sketch) take reference to ContiTech Germany information.

    The belt speed v could be in the range 0.5 mps to 1.5 mps depending upon the lump size. Bigger the lump, lesser is the speed.

    For lumpy material cleat spacing should be equal / greater than 1.5 to 2 times the lump size (maximum corner to corner length of the lump). The cleat length (clear width between 2 side walls) should be also 1.5 to 2 times lump size as said earlier.

    Conveyor resistances:
    The conveyor resistances and power is being calculated in a manner similar to usual belt conveyor but with applicable conveying friction coefficient, etc. The carrying belt bottom side is moving on idlers like usual belt conveyor. So its conveying friction coefficient would be lesser than the return run. As for the return run, belt side walls are moving on rollers. In this case, the conveying friction coefficient will be more because it will have more hysteresis losses in rubber. One can design the steep angle conveyor taking the common average conveying friction coefficient as 0.10.

    It is to be noted that this being steep angle conveyor, the dominant resistance will be lift resistance and thereby the conveying friction coefficient value as considered above for conveying will not have decisive influence. However, designer can take different value of conveying friction coefficient if he has specific data.

    The belt pulley wrap resistance will be more because of thicker / heavier belt. One can consider this as 3 times the usual conveyor pulley wrap resistance.

    The pulley turning resistance will be as for usual belt conveyor.

    Such conveyor cannot have external scraper. So its resistance will be absent. It will have mostly one internal scraper and thereby its resistance will be applicable (as for usual belt conveyor).

    Skirt board resistance can be taken same as for usual conveyor (safer side).

    The pulley wrap resistance, pulley turning resistance, internal scraper resistance and skirt board resistance are additional to ‘main resistance’ calculated by conveying friction coefficient f = 0.10.

    The belt width and its construction features will be as recommended by belt manufacturers. The belt width for inclined conveyor without snubbing / deflection on cleated side, is likely to be around 1.6 times cleat length and for Z-type conveyor it could be around twice the cleat length. Finally both these will be as given by belt manufacturers.

    Steep angle conveyor inclination limitation arises due to provision of walkway on the sides for maintenance. At 55 degree incline, the ratio i.e. (Step rise) Divided by (Step width) becomes 1.42 which is quite high. Therefore for higher inclination the option is Z-type conveyor. In this case, the maintenance walkway will be for horizontal portion at lower level and horizontal portion at upper level. There is no need to go in vertical zone and hence any access is not necessary for this zone. The conveyor portion to be maintained in this zone is simply driven down or up at horizontal level when to be attended.

    Ishwar G. Mulani
    Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 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
    Attached Files Attached Files

  3. #3

    Further References

    There are several publications which have recently been resurrected by the efforts of Marcel D regarding all aspects of bulk solids handling.
    Cleated sidewall belts are mainly addressed by Trellex/Flexowell, Mors & the articles are thorough, professional & essential reading.
    Search & you shall find.

    One thing about any vertical belt is guidance. Although the carrying rollers can be excluded throughout the vertical travel there should be some means to restrain a snapped belt. Failure will result in the creation of a conical pile on the floor. To limit the size of the pile it would help if the belt fall was arrested by simple low friction guides which limited the belt movement. These guides would stand clear of the belt while running but catch a falling belt & prevent further There would also be less work to restore the conveyor.
    John Gateley
    johngateley@hotmail.com
    www.the-credible-bulk.com

  4. Hello,

    In the posting yesterday (21 January), I missed to show profile for belt along with the cleats used for Z-type conveyor (horizontal - vertical - horizontal conveyor). The attached sketch shows cleat profile for incline conveyor and also for Z-type conveyor.

    Now, these sketches show material filling keeping 20 mm clearance at edge. The capacity decided by considering the edge clearance, should correspond to the design capacity.

    Once the various resistances in conveyor are decided; the calculation of power and belt tensions at various points is a routine affair as for usual belt conveyor.

    Ishwar G. Mulani
    Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 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
    Attached Files Attached Files

  5. #5
    Join Date
    Aug 07
    Posts
    37
    Quote Originally Posted by I G Mulani View Post
    Hello,

    The reader is to acquaint himself about the application, use and constructional aspects of steep angle conveyor from the relevant literature by the belt manufacturers and manufacturers of such conveyor. Here, it is understood that the reader is already familiar about such conveyors.

    This reply deals with the following two main issues:
    1) Steep angle conveyor sizing i.e. deciding the belt width, pocket width, speed, etc..

    2) Calculation of resistances which are input for calculation of belt tension and power.

    Conveyor sizing :
    The belt conveyor capacity is calculated in a manner similar to bucket elevator i.e. material contained in each pocket. The pocket is formed by belt flat upper surface, 2 side walls and cleat/s, as against one bucket. The number of pockets discharged per hour is (Velocity v mps) x 3600 Divided by (Cleat spacing in metre).

    The hourly discharge rate mtph = (Material weight kg in one pocket) x (Number of pockets discharged in one hour) Divided by 1000.
    This value should be equal or greater than the required design capacity.

    As for the material contained in one pocket, refer the sketch attached with this post reply at the end. The material volume contained in one pocket is the shown cross section area multiplied by the length of the cleat. Convert this into material mass kg in one pocket, by multiplying it with bulk density. The angle ‘beta’ is surcharge angle of the material, which could be say around 20 degree, etc. as applicable for belt conveyors. The angle ‘delta’ is conveyor inclination to horizontal.
    The aforesaid sizing procedure (sketch) take reference to ContiTech Germany information.

    The belt speed v could be in the range 0.5 mps to 1.5 mps depending upon the lump size. Bigger the lump, lesser is the speed.

    For lumpy material cleat spacing should be equal / greater than 1.5 to 2 times the lump size (maximum corner to corner length of the lump). The cleat length (clear width between 2 side walls) should be also 1.5 to 2 times lump size as said earlier.

    Conveyor resistances:
    The conveyor resistances and power is being calculated in a manner similar to usual belt conveyor but with applicable conveying friction coefficient, etc. The carrying belt bottom side is moving on idlers like usual belt conveyor. So its conveying friction coefficient would be lesser than the return run. As for the return run, belt side walls are moving on rollers. In this case, the conveying friction coefficient will be more because it will have more hysteresis losses in rubber. One can design the steep angle conveyor taking the common average conveying friction coefficient as 0.10.

    It is to be noted that this being steep angle conveyor, the dominant resistance will be lift resistance and thereby the conveying friction coefficient value as considered above for conveying will not have decisive influence. However, designer can take different value of conveying friction coefficient if he has specific data.

    The belt pulley wrap resistance will be more because of thicker / heavier belt. One can consider this as 3 times the usual conveyor pulley wrap resistance.

    The pulley turning resistance will be as for usual belt conveyor.

    Such conveyor cannot have external scraper. So its resistance will be absent. It will have mostly one internal scraper and thereby its resistance will be applicable (as for usual belt conveyor).

    Skirt board resistance can be taken same as for usual conveyor (safer side).

    The pulley wrap resistance, pulley turning resistance, internal scraper resistance and skirt board resistance are additional to ‘main resistance’ calculated by conveying friction coefficient f = 0.10.

    The belt width and its construction features will be as recommended by belt manufacturers. The belt width for inclined conveyor without snubbing / deflection on cleated side, is likely to be around 1.6 times cleat length and for Z-type conveyor it could be around twice the cleat length. Finally both these will be as given by belt manufacturers.

    Steep angle conveyor inclination limitation arises due to provision of walkway on the sides for maintenance. At 55 degree incline, the ratio i.e. (Step rise) Divided by (Step width) becomes 1.42 which is quite high. Therefore for higher inclination the option is Z-type conveyor. In this case, the maintenance walkway will be for horizontal portion at lower level and horizontal portion at upper level. There is no need to go in vertical zone and hence any access is not necessary for this zone. The conveyor portion to be maintained in this zone is simply driven down or up at horizontal level when to be attended.

    Ishwar G. Mulani
    Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 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

    Thank you very much eng Mulani, from your answer I understand your great experience,
    the answers are concrete and direct as like me.

    Thanks again for your help.

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