we did experience belt fires but the bearings never heated up.

The roller just froze up and the friction between the belt and the roller initiated the fire.

Frecuent portable scanning Infrarred inspection covers both issues.

Marco ■

Check ou the following site. I am sure they will have something that will be what you are looking for.

Gary Blenkhorn

http://www.microwattcontrols.com/ind...ry.php&catid=4 ■

I have used succesfully infrarred scanners to detect overheating components . I preffer to use longuer wavelenghts like say 11 micron to get away from the sun spectral emision.

local monitoring could be done , with thermistors and a reference ambient temperature. nevertheless cables nust be used to take the signal out. and in a belt conveyor cables are an additional nuissance ,

temperature sensitive paint can be used also , nevertheless if you are handling coal averything could be covered with coal dust.And you might not see a thing.

I am attaching a photo that shows an electrical connection overheating,

When I took this photo I was looking for gaskets overheating not cables.

the problem with ir scanners is that you must have a clear path from the target to the camera what is not alvays easy in coal mining. ■

Sorry I forgot the picture

Attachments

hot equipment (JPG)

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Try:

http://www.protectowire.com/applicat...plications.htm

This is what you seek.

Lawrence Nordell

www.conveyor-dynamics.com ■

Nordell is right

I have tried some of this linear temperature detectors.

Linear detectors come with different features.

some of them have two cables inside a thin pipe, the pipe is fiiled with a salt that melts at a given temperature. and turns conductive , allowing contact beween the two cables so they can be used to trigger an alarm .

Other linear heat detectors have a liquid inside apipe and a pressure meter in one side pg the thinpipe, as the liquid expands with temperature the sensor reads the additional volumen and can be also used to trigger an alarm, this ingenerall meters average temperature overall the long thin pipe.

Finally some linear temperature switches have either a solid or a liquid that evaporates when reaxching a given temperature , triguering a sudden increase in pressure in the containing tube.

this pressure can be used to triguer an alarm too.

Be carefull when you install this systems and try not to break the cables, or the tube .

This pipes will come in the way of the maintenance people so take this into account when selecting how to install them or the maintenance team witll take them appart (not carefully). And you will be left sensorless.

regards

Marco ■

One of our clients storage building was set with linear temperature detectors .

although they were able to detect a rise in the temperature, there was no way to see where the hot spot was . Nor was there any way to remove the material other that by pay loader. Notice I am saying a rise in the temperature and not high temperature. the linera sensor was made with an internall wire that esxpanded faster than the shrowd , something like the liquid filled type.

design your access so you can get where it is needed and take pre designed corrective actions.

Marco ■

I looked at the catalogue recommended by Nordel. In the materials handling section they show a linear heat detector and they claim that they can pin point the location of the heat source. This is very interesting. My guess is that once the current is established, hey measure the resisance of te conducting cable, in this manner they can know at what length of the detector the heat source triggered the alarm. This might be what you are looking for. Take a very close look at the catalog and check with them about the installation requirements.

Good luck!

Marco ■

Dear Sr. Flores:

The Protectowire is not a pipe. It is a twisted two wire pair that when the temperature rises sufficiently to melt the plastic separator the two wires contact giving annunciation. It has been in use in power plants throughout the USA for many years.

Lawrence Nordell

www.conveyor-dynamics.com ■

Forgot:

THe postion of the wire short is by the growler method practiced by your telephone company to chase cabel shorts. The detection of location is quite accurate with the supplied electronic hardware.

Lawrence Nordell

www.conveyor-dynamics.com ■

Very frecuent.

Attachments

almacen en fuego chico (JPG)

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