Here is a go at it with some hypothetical parameters:

T1: denotes the tight side or high tension side of the drive pulley

T2: denotes the slack side or low tension side of the drive pulley

Assume the lowest tension along the belt will always > sag limit

Assume normal lagging has a friction f = 0.30

Assume ceramic lagging has a friction f = 0.40

Assume the normal lagged conveyor has a T1 = 1000 units

Then T1/T2 = e^(theta x f) where theta is wrap angle in rad. and

we assume the drive pulley wrap angle is 180 degrees:

1) normal lagging with f = 0.30; T1/T2 = 2.566 > T2 = 389.7

2) ceramic lagging with f = 0.40; T1/T2 = 3.514 > T2 = to solve

Solving for the change in T1 and T2 can be expressed by dT:

(T1-dT)/(T2-dT) = 3.514 with the old T1 and T2; we find dT

Given: (1000-dT)/(389.7-dT) = 3.514

yields: dT = 146.956 so,

Change in T1 is 1000-146.956 = 853.04 or 14.7% drop in T1

Pick you own numbers and see what you get. Hope I did not flub so late at night. ■

Who or what is BoF? ■

BOF

Basic Oxygen Furnace

or short for Boffin

Cheers

LSL Tekpro ■

My Continental book gives :-

Dry operation

Bare steel pulley 0.35 - 0.4

Rubber, herringbone groove 0.4 - 0.45

Ceramic, herringbone groove 0.4 - 0.45

Clean wet condition

Bare steel pulley 0.1

Rubber, herringbone groove 0.35

Ceramic, herringbone groove 0.35 - 0.4

Clay soiled wet

Bare steel pulley 0.05 - 0.1

Rubber, herringbone groove 0.25 - 0.3

Ceramic, herringbone groove 0.35

Just another reference. ■

Dilip..you said:

"I wanted know whether I will be able to reduce the counter weight by the application of Cermic Pulley Lagging."

To which the answer is yes you can, as long as you still have enough tension in the system after reducing the cwt, so as to maintain no more than 2% sag anywhere, and also still have no drive slip.

In this way, you can score a bit by using ceramics.

The main reason for the ceramics however, is normally to reduce the pulley lagging wear rate.

All well in theory, but in practice ceramics tend to fall off before they have worn out.

LSL Tekpro ■

Bol

Reasons for conservative friction factor:

- We are normally bound to the clients conservative specifications, and you must remember that the customer is always right (especially even when he isn't)

- On a lot of occasions the slack-side tension is dictated by the minimum tension allowed for belt sag of 2% so there is no point going high on mu

- I would normally not use more than mu=0.4 even for ceramics, as they do polish up after a few years of use.

- If for example you can use an St 800 belt insread of St 1250 by increasing the of mu , then I still would not bother, as it is too easy to damage such a weak belt, depending on what you are carrying of course

Regards

LSL Tekpro ■

My required power transmission is same in both the cases(for a rubber lagging or a cermic pulley lagging).

Now, if T1 & T2 both reduces by the application of cermic lagging, does it mean the initial tension of belt T0 get reduced(as To=T1/2 +T2/2) in my existing system?

But the initial tension T0 is governed by Counter Weights or Screw Take Up or any other take up arrangement.

Does that mean I should reduce my initial tension T0 by lowering the courterweight?

I am a bit confused.

Please clarify my doubts. ■

urwithdilip

What are you trying to achieve?

LSL Tekpro ■

I wanted know whether I will be able to reduce the counter weight by the application of Cermic Pulley Lagging.

Dilip ■

Dilip:

Do you read what is presented in this forum? I think not? Go back 9 entries before your last request in this thread. I demonstrated through a simple example the saving in belt tension. From this example, all details are given.

Others have also published similar works in other threads.

Do your homework. ■

We are supplier of wear protection alumina ceramics, ceramic grinding media, precision ceramic parts and inert ceramic balls (catalyst bed support media).

Please check our blog web for more info about our products:

https://aluminaceramics.wordpress.com

If you are looking for an alternative supplier, we will be your choice.

Hope to work with you in the near future.

Best Regards,

Zhang Hongbo

Sales Manager

Qingdao CBC Co.,Ltd.

www.cbcceramics.com ■

Wear resistant ceramic lining – Alumina, zirconia & ZTA

Ceramic grinding media – alumina & zirconia

Steel & rubber backed ceramic plate

Pulley lagging

https://aluminaceramics.wordpress.com/ ■

Dear John,

Belt to Pulley interface sliding friction coefficient design values on shell used at CDI:

steady dynamic

1. Steel bare (dry) .................... 0.25 0.28

2. Steel bare (wet) ................... 0.20 0.23

3. Rubber lagged ( dry) ............ 0.35 0.40

4. Rubber lagged (wet) ............ 0.30 0.35

5. Rubber lagged (ice) .............. 0.22 0.25

6. Rubber lagged (slime) .......... 0.28 0.34 iron, bauxite, nickel

7. Ceramic tiles (dry/moisture).. 0.40 0.45

8. Ceramic tiles (ice, slime) ....... 0.32 0.36

Note; These are nominal values that may be changed with higher belt tensions, critical braking, and high lift risk factors. Certain field conditions may supercede these values. ■

John,

In addition to the general numbers provided by Mr. Nordell, you have to consider the lagging profiles for rubber lagging and ceramic lagging (under the different usage conditions Larry gave); and the different coefficient of friction values for the rubber compounds used (these should be available from the lagging manufacturer).

Finally, if you have rubber lagging that has glazed due to slippage - treat it as bare steel (or buff the glazed surface).

Regards, ■

Morning John..

For other definitions relating to pulley lagging, we here in South Africa have spent some effort on improving our SANS (SABS) pulley spec to now also include the definitions of pulley lagging requirements.

The South African Standard is SANS 1669 part II

Good luck

LSL Tekpro ■