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Belt Conveyor Top Metal Detector Long Fault

07/30/2011 2:33 AM

Dear All,

Iam working for cement industry and these days many times our coal mill is getting tripped due to metal detector long fault (metal detector located on top of the coal feeding belt conveyor), it seems that there are 2 or 3 metallic pieces that are coming continously in the mill feed stream. We are using weigh feeder to extract material from raw coal silo from where there is a single belt conveyor that feeds the coal mill. We have one belt top magnetic separator that separates metallic pieces upstream of the metal detector. We are not able to correctly pinpoint the problem that causes the long fault - may be there are metallic pieces coming continuosly past the magnetic separator or some instrument malfunction because of over sensitivity. If you have any experience with this kind of problem and how you overcame it, please let us know.

Best Regards,

Vivek

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#1

Re: Belt conveyor top metal detector long fault

07/30/2011 2:54 AM

What constitutes a "long fault"? The metal detectors I have seen surround the conveyor rather than lie above. If metal is detected, the conveyor can be stopped, or a suitable portion of product can be diverted. You could then search for the metal with something like an airport security wand.

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#2

Re: Belt Conveyor Top Metal Detector Long Fault

07/30/2011 1:01 PM

Dear Mr.Vivek,

What is the coneyor belt's carcass? is it fabric or steel-cord belt?

Thanks & regards,

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#3

Re: Belt Conveyor Top Metal Detector Long Fault

07/30/2011 11:21 PM

Does some of your coal contain more FeO? Perhaps more FeO than the detection limit but less than your magnetic separator can separate.

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#4

Re: Belt Conveyor Top Metal Detector Long Fault

07/31/2011 2:06 AM

How is the belt spliced? metal?

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#5

Re: Belt Conveyor Top Metal Detector Long Fault

07/31/2011 3:09 AM

Ok now the belt has stopped, on inspection did you find metal pieces.

We had similar problem, even installed a paint spotter that sprays a dot of yellow paint on the spot where the trip mechanism was activated. In the long run we reduced the sensitivity of the metal detector and installed a magnetic conveyor head pulley. And found that small pieces of bin liners shovel teeth nuts and bolts that slipped past the metal detector got cort at the head pulley. Bigger pieces got well spotted by the metal detector and cleared accordingly. That little spotter worked like magic and was so easy to find the metal piece.

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#7
In reply to #5

Re: Belt Conveyor Top Metal Detector Long Fault

08/01/2011 12:18 AM

Hi,

Manytimes small nut bolts, pieces of scrap iron, steel wire ropes past through the metal detector/ magnetic seperator. These are detected at trip mechanism site. Hence a magnetic seperator is required near discharge pulley side of the conveyor which will check the small pieces. Anyway it is not mentioned whether any metal material is found at tripping location.

However as stated above magnetic seperator is necessory to protect onward system. All metal particles are to be removed at suitable time from main seperator as sometimes small pieces pass through if crowded. Cause of metal material coming from mine site is also to be detected.

A K Billore

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#8
In reply to #7

Re: Belt Conveyor Top Metal Detector Long Fault

08/01/2011 7:09 AM

So what you are saying (without telling us what metal types you are talking about) that the magnetic remover, is not removing all metal.

Is that because some parts are non ferrous?

Are there "removers" that can work on non Ferrous as well?

What is yours supposed to do?

The metal detector which will probably work for all metals, then detects the pieces and stops the band......

To my mind, you need to fault find the "remover".....Maybe is not set up correctly, has a fault, does not see certain sizes of material, there could be many problems.....

But although I am good with logical problems, I do not work on such equipments.....but apply logic first, then get the repair service there.....

At least nothing is getting through......

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#9
In reply to #8

Re: Belt Conveyor Top Metal Detector Long Fault

08/04/2011 5:16 AM

Metal detectors and magnectic detectors are installed to check nonferrous/ferrous metals as per requirement. these are posted at a height above the conveyor belts so that the material being conveyed in belt pass freely. If some metallic object passes , is attracted by the detectors. If the size of the foreign material like shovel shoes or ropes is more it gets on hanging above the belt. If some other material also pass through it may get attracted by the detector but may fall due to fouling of conveying material due to space limitation. This has been many times if the large size material is not removed in time. Hence it may be clear that there is no differentiation as far as detection is concerned .These are practical problems arise during the operation.

A K Billore

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#6

Re: Belt Conveyor Top Metal Detector Long Fault

07/31/2011 6:23 AM

Is metal actually found, or has the metal detector itself a problem? You were not specific....

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A K BILLORE (2); Andy Germany (2); herbie (1); michael 1959 (1); regsoft (1); Sganesh (1); Tornado (1)

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