Help with automatic belt tracking system - belt conveyor

Hi all,

I am designing an ‘automatic steering system’ for a flat belt feeder (belt conveyor).

The flat profile of the belt and the lumpy nature of ore can cause the belt to go of track (due to the forces applied by lumps loaded toward the edges of the belt). The automatic steering system shall detect the belt drifting from alignment and take corrective action.

In industries like printing, paper, textiles, tire & rubber, etc this type of system is known as ‘web guiding’ system. Unfortunately, I have no knowledge of similar systems for belt conveyors (mining).

The biggest challenge (I believe) is to find a sensor that reliably detects the drifting of the belt (at the edges):

· Thickness ~ 48mm

· Width 2600mm

· Length ~ 120m (conveyor length ~60m)

· Maximum lateral movement allowed: 130mm (both sides)

If any of you have come across a similar application for mine conveyors, I would greatly appreciate if you could share the details of your experience with me.

Thanks in advance.

Regards,

LJAM

What will be the "corrective action" when the belt drifts?

pulley skewing (± 5º) mechanism

I envisage that to be a skewing mechanism at the tail-end pulley (driven by a linear actuator) ... although I am not too concern with this bit right now

Hi

Far as I know there is 2 kind of sensors.
1.You can use Analog Ultra sonic sensor (Transmiter and Reciver)
When the beam is coverd or not coverd you need to correct.
The analog give you how much you need.
2.You can use 2 photo eye which install very close one each other on the edge of the belt.
If 1 is on and 2 if off evry thing is OK
If both of them is ON or OFF you need to correct.
The corrction mecanisim can be rotate shaft or side guide.
This can not work for high speed belt.
Important thing:
The belt create static electricity and when the power discharge its damage the sensors and the PLC.
If you need more help feel free to PM me.

All the best

We have 3 belt tracking systems in our plant that track belts at speeds of 350mpm. Two of the systems were acuator types with acme thread and brass nuts to adjust the tail pulley. They were very high maintenance so we modified the equipment with an Eckels-Bilt tracking system. Not sure if they will have a system that will met your needs but for us they are great.

http://www.eckelsbilt.com/solutions.php

As for sensors we use Banner Q50 series Laser sensors, they have very good range so they can be mounted out of harms way.
The Eckils are air acuated so we use some of the exhaust air to blow on the sensors which keeps them clean.

We let the belt drift between the two sensors (1 mounted on each side of the belt) rather than trying to keep the belt tracked over 1 of the eyes. This greatly reduces the wear on the actuator.

Hope this helps,
Chad

any documentation available? brochures or flyers (*.pdf)

Thank Arik and Chad for your replies.



Chad,

Can you please provide details of your conveyors? (i.e. belt dimensions, material conveyed, industry, etc.)

I would like to hear more about the maintenance problems you faced with the actuators …there may be a lesson to learn for me.

Do you have a brochure or flyer of the Eckels Bilt equipment (*.pdf) used in your plant? If you have it, can you please forward it to me?

I will try to contact the vendor but I can not see any indication of distributors “down under” (I’ll give it a shot anyway).

This feeder I am working on feeds one of the mine’s crushers and the ore transported is run-of-mine (excavated from the pit), thus, is an area with lots of dust (and vibration due to a vibratory screen nearby) … optical and laser sensors normally do not work well in this type of environment … The following is a shortlist of characteristics that a sensor shall comply with:

• Dusty environment.

· High vibration.

· Exposed to the elements.

· Narrow target: belt edge thickness ~48mm (some movement is expected – though limited due to positioning close to pulley)

· Instrument range: ±130mm (both sides)

Thanks and Regards,

LJAM

I did a system like this once but it was a much smaller belt. We used a manual air valve with a long lever arm. The belt was adjusted to move towards the lever arm. When it hit the valve extened the roller making the belt track the other direction. While running the valve was correcting a couple of times a minute. It was very simple and it worked great. The trick is to make sure the belt tracks toward the sensor.

LJAM,

One belt is a rough top belt at 72" wide by 20' long that is used in a rewind operation for carpet cushion rolls. The other 2 are loose weave belts at 84" wide by 40' long they are used in a cutting operation with vacuums that prevent the foam bun from being pulled up by the knife.

As for the actuators the dust from the foam cutting would imbed into the grease which would in turn destroy the brass nuts. These belts are a little over 10,000 each, so after destroying a couple it was cheaper for use to modify the equipment with the Eckils tracking system.

Thanks for your comments

Kind Regards,