8/9/2019 2012 Tips Construction Oct 57 En

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Conveyor belts

Measurement of belt conveyorcapacity

Issue 57 | October 2012METSO´S NEWSLETTER FOR CONSTRUCTION CUSTOMERS

AUTHOR Raul Camargo | PROOFREADER Christian UllmannPUBLISHED BY METSO BRASIL IND. E COM. LTDAQuestions should be sent to the e-mail below. Your question can be the subject in later issues.E-MAIL marketing.br@metso.com | WEBSITE www.metso.com All rights reserved.

It is always important to check whether thecapacity of your plant’s belt conveyors isadequate according to the project design

specications.When a conveyor is overloaded with material,

the service life of its replaceable parts, such asrollers, drums and belt, may be shortened aswell as lead to structural failure (such as warpingof belt rests, trusses and supports).

Spillage of material also means high cleaningcosts besides increasing the risk of accidentsinvolving personnel.

Another important point is the analysis ofthe ow of material at the plant. An overloadedconveyor transfers an excessive amount ofmaterial to equipment that is downstreamand can cause jamming of machines, resultingin losses of production or in a nal productwhose quality is lower than recommended.

How can I measure the capacity of myplant’s conveyors? There is a practical method for measuringconveyor capacity which is to collectand weigh the amount of material beingtransported on a one-meter length of theconveyor belt and measure the speed (velocity)of belt travel.

Activity A: weighing the material1- When the equipment is running and at itsfull capacity, interrupt its operation.2- Access the conveyor and mark off a one-meter length of the belt (see picture 2 below).

The use of plates or wooden boards to mark thelimits of the one-meter section is recommendedso as to avoid inadvertent collection of materialthat is beyond the one-meter limit.

As a safety precaution, make sure that theequipment is turned off. It is fundamental thatpower to the conveyor is cut off and locked soas to avoid accidents involving personnel.

3- Collect the material that is on the one-meterlength of the conveyor belt (3) and place it in aplastic bag or other container so that i t can besubsequently weighed.4- Weigh the collected material.

Activity B: measuring belt travel speed To complete the measurement of theconveyor’s capacity, we should measureits operating velocity. This measurement isperformed with the aid of an instrumentcalled a tachometer. There are several typesof handheld industrial tachometers. You canchoose the simplest as long as it displaysvelocity in ‘meters per second’ (m/s) or ‘metersper minute’ (m/min).

With the conveyor running, carefully bringthe tachometer’s rotating part (wheel oradapter) in contact with the moving surface ofthe belt. The velocity of the belt will be shownon the tachometer’s display screen.

Calculating the capacityLet’s suppose that the data found uponperforming activities A and B were:Weight (m’(L)): 130kg/mVelocity (v): 1.84 m/sUtilizing the formula for capacity expressed as l(m):l(m) = 3.6 x m’(L) x vWe will nd:l(m) = 3.6 x 130 x 1.84l(m) = 861.12 t/h (tons per hour) => Capacity

measured!

If your tachometer displays velocity in m/ min, use 0.06 instead of 3.6 in the formula tocalculate the capacity in tons per hour (t/h).

This information on the conveyor’s capacitycan be compared to the project designspecication or even used to verify whetherthe equipment that is fed by the conveyor istechnically capable of processing the materialreceived. ■

adapter or wheel

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