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Design of Belt Conveyors Step #2 Getting a Belt Profile ©2012 Dr. B. C. Paul Note – Material in these slides include screen shots from the program “Belt.

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Presentation on theme: "Design of Belt Conveyors Step #2 Getting a Belt Profile ©2012 Dr. B. C. Paul Note – Material in these slides include screen shots from the program “Belt."— Presentation transcript:

1 Design of Belt Conveyors Step #2 Getting a Belt Profile ©2012 Dr. B. C. Paul Note – Material in these slides include screen shots from the program “Belt Analyst” by Overland Conveyors. Credit for program and interfaces are given to Overland Conveyors. Procedures taught and many tables used were developed by the Conveyor Equipment Manufactures Association. The author also referenced previous notes developed by the author.

2 Move onto Belt Profile A basic conveyor Has a carry side -A head and drive -Pully -A return side -And a tail and -Take-up pully

3 Lets Work on the Profile 1000 feet level 600 feet up a 35 foot roll 500 feet level 750 feet down 55 feet into a trough 50 feet level 800 feet up a 30 foot roll 500 feet level 575 feet down 50 feet to the base of the slope

4 Input the new length Now insert that uphill flight To do this put the curser on The spot just below where You want to insert and then Right click insert flight.

5 Note We Are Getting a General Picture of Our Conveyor While We Work

6 And There Is One Twist and Turn Special

7 Lets Start Checking Out the Drive They need about a 200 hp motor to supply 158 hp. - 25,500 lb take-up Wow.

8 I Do Not Want My Belt Drive to Be on My Head Pully Instead I want to separate the drive From the head pully and put it here Not unreasonable – who wants Sticking coal dust going into the Drive – I want room for a scraper. I also want the drive on a level Spot that does not accumulate Water.

9 The Problem of the Mirrored Return Note that for every flight I inserted delivering Material the program has automatically inserted A corresponding return The auto return told the program to do this. Now I want to put the drive system in the Middle of section 11. That means I need to seize control and split A belt flight. To do this I will go to user Mode.

10 Split the Flight I am set to user I place the curser on the flight I wish to Divide. I right click the mouse to Activate a drop down menu. On the menu I pick divide flight into two segments.

11 It Divides into two parts Note it divided 500 feet into two 250 foot segments. If I don’t like the Division I can position the curser and type in the change.

12 Now I’ll Move My Drive Pulley Click on the Drive Pulley Click on Move It asks me where to Move it.

13 There is Our New Drive Location

14 Of Course I Probably Also Have Some Bend Pullies around the Drive

15 I Could Add Those Bend Pullies (I’m not really going to) Interesting item – when I place the curser and click insert pully the program already knew It was a bend pully so I did not have to label anything. Also note that the conveyor Sketch shows major pullies – not bend pullies.

16 Now I’m Going to Question the Position of the Take-Up Having the end roller move on a short Belt is one thing. When its more than A few hundred feet you can’t have the Load point moving all over creation. And a 14,500 lb take-up weight is not A little thing either.

17 Short Flat Conveyors can have tail pulley pull back and forth

18 With Good Headroom One Can Use a Gravity Take-Up

19 Long Conveyor Confined Head-room

20 A Program Mechanics Problem I decide I want to put a take-up unit in the Last 1000 feet before the tail pulley. I put my curser on the section and try to Split it. I get no option to do so. (The program has to have one conveyor Segment it controls to make conveyor Delivery and return lengths compatible).

21 I’ll Beat That Problem With an Insert Flight Command Note it inserted a flight and adjusted the length of its Segment to compensate.

22 Now I Have Split Things the Way I Want

23 My Next Problem Is How to Insert My Takeup Pulley I can insert a drive pulley (I already did that) I can insert a pulley but that will be a bend pulley The trick I will use is to move my takeup pulley

24 To Move A Takeup 1- Put my curser on the take-up to Be moved. Click on Move It asks me where to move it to I click on my desired location.

25 And I Got My Result

26 I’ll Add Some Bend Pulleys to Help me wrap things

27 Now I’ll Check Pulley Specs Click here to activate the Pulley Wizard It will ask permission to add a few Segments and snubs it feels are needed.

28 It adds short flights between pulleys

29 Going Into the Wizard It Allows Me to View My First Pulley When I’m done Here I can click Next to move on To the next pulley

30 The Wizards Coordinate System T1 is the incoming Belt direction T2 is the outgoing Belt direction 0 direction is the Forward direction For material These values in bold orange are program calculated but can be replaced by user

31 The Left Side Determines Incoming and Outgoing Belt Directions A 575 foot section going down hill at just shy of 5 degrees Comes into the pulley The return side goes 575 feet up hill.

32 Moving onto the Drive Pulley Area Does Not Look Good I’d like to see this Mess a little better Left click in the view Field and then use The center scroll to Zoom in.

33 Our First Bend is Doing Nothing Note that the pulley Under current Review is Yellow Note that right now Our yellow bend Pulley is Do little more than Touching the belt

34 OK – Time Out – What is a Wrap Angle? It is the angle over which the belt is in contact with The pulley.

35 My Miracle Correction First I lower the position at Which the belt comes into The bend pulley (the value Was 0, now it is -5). My reason for doing this is To provide room for the Motor drive to run without Plowing into the carrying Belt overhead. Note all of this moved down.

36 My Next Step I reversed the direction of pulley Rotation from counter clockwise To clockwise. Note that this made the belt Wrap 180 degrees around the Pulley – although why a belt Would reverse direction and Pull away from a pulley in mid- Air is a mystery of physics. Note – the drive Moved up into the Space I provided.

37 For My Next Trick I next reverse the Direction of the belt As it exits my bend Pulley. It was -3, Now it is 5. (Note that the positive Direction is the way The load is moving on The carry side).

38 Now I Will Try to Increase Contact on My Drive Pulley I will make the belt Leave my bend pulley On a downward Trajectory {it was 0 Now it is -1} (which as You can see increases Wrap on the drive Pulley)

39 A Manual Correction I added the Degree angle to the Wrap angle on the Bend pulley so the T2 direction would Match. (I’m not really sure Why the program did Not make this Reconciliation on its Own)

40 Time to Back Up Why was I so eager to increase the wrap angle around the drive belt? –The Drive Pulley is where the power of the motor is transferred to the belt. – If the Pulley spins we won’t get much action. So what makes the pulley not spin? –#1 The coefficient of friction with which the pulley grips the belt.

41 Standard Pulley Grip Surfaces

42 Oh Heavy Man Of course the flip side of a high Friction grip on the belt is belt Wear. These are called Winged Pulleys

43 More Reasons for a Drive Pulley Not to Spin #2 – The Force with which the pulley is held against the belt. –Ya – that physics stuff about the frictional force is the force pinning the surfaces together X the coefficient of friction

44 That Force Comes from T1 and T2 Oh Gosh – This is looking like Statics All over again. T1 T2 The flip side of pinning the Belt tight against the pulley Surface – that means a heck Of a big T1 and T2 which Means if I don’t want to Break my belt in two I need One heck of a strong $$$ Expensive belt.

45 Reason #3 The length of the area over which that force and coefficient of friction is applied – ie the wrap angle. –If I lengthen the area of contact I can use less aggressive pulley surfaces –And have lower T1 and T2 –Both of which save me money and wear

46 After That Detour I Move to My Next Pulley I currently have another of Those wild miracles where A belt floats up and Contacts a pulley (which I Suspect is not really going To happen) This is the Drive Pulley!

47 I Reverse the Direction of the Pulley It was clockwise – now it is Counter-clockwise. This actually looks pretty Good to me – I’ll move on To the next pulley

48 Its Another Bend Pulley Since I am happy with this Set-up I will move on. (Incidentally I could go Through my pulleys in Any order using the drop Down menu)

49 Oh – I’ve Got Another Mess Around My Take-Up

50 With the Aide of My New Found Skills I Fix This

51 Well Moving onto the Take-Up Was Not Friendly

52 The Reverse Rotation Direction Trick Works Well

53 I Love This One – How Do I Get a 360° Wrap Around a Pulley? Mr Wizard must have Found one of the better College frat parties in Town.

54 Reverse Direction

55 And My Tail Pulley Is Ok

56 Lets Top Our Design Off With Peripherals When I load my material –I will use skirt boards –I will also assume I have to accelerate my material from zero spead I will discharge material over the end of my conveyor without use of plows or trippers –But I will use belt cleaners on the return side

57 Skirt Board Rule of Thumb Length = 2X Belt Speed / 100 Our Belt Speed is 500 –2X5 = 10 feet

58 Go to My Belt Profile Note there is a slider for me to see more About my profile. I this case I am Worried about my 1000 ft initial Carry section.

59 I Input My Skirt Board Length The program automatically figured out it was going To have to accelerate the material

60 Put In My Belt Cleaners on the Return Just Past the Head

61 Now Its Your Turn Conveyor Assignment #2 –Take your conveyor from assignment #1 –Assume your profile is 500 feet up hill 5 feet 200 feet on the level 650 feet down 7 feet to the main line conveyor –Input the profile and get you take-ups and drives in place –Turn in your Belt Analyst File

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