It sounds like you have a poorly designed system.

The feed chute must be directed onto the centerline of the belt - if not it will cause the belt to mistrack to the opposite side that it is loading on to and can easily create spillage. DEflectors can be placed in the chute to correct errors in the design.

The size, speed and HP of the receiving belt must be such that it is capable of handling the load being fed onto it. Without knowing the particulars this would be very hard to answer as to your set-up.

Typically on any conveyor the centerline should not vary more than 1/8".

Idlers should be the same height and centered on the conveyor. All pulleys are to be squared to the frame in which they are mounted. If the belt is tracking off the pulley then the pulley may not be square to the frame.

Tracking (training) idlers typically are set approx 1/8" higher to allow additional force on the rollers to confirm load and "steer" the belt into the correct centerline. If these are required then there is a underlying reason it is not tracking properly - typically it is poor installation or a belt splice that is not square.

Never heard of a 30 deg idler. Typically they are 20, 35, or 45 degree.

The risks of mistracking on the retunr side are:

- Increased friction if rubbing on frame causing increase in HP requirements.

- edge wear and damege to the belting.

- I have seen the belt actually cut into the system frame enough to cause structural failure. ■

Hi Meejay..

A couple of points..

Firstly, the strange theory that all belts in series must be the same speed is simply not true. So don't worry about this, as long as the slowest belt is fast enough to carry the load without spillage.

Secondly if you are loading centrally but have to use tracking idlers, your conveyor pulleys are not aligned properly, the idlers are not normal to the belt or the belt splices are not straight.

For example, I was underground in a coal mine yesterday. There was one conveyor there that had to wind its way around the pillars left to support the hanging wall, which were all over the place. The centre-line of this conveyor runs off centre many times by about 1.5m, but the belt simply follows the conveyor as the idlers are set normal to the belt and have one degree forward tilt.

It is fed by a straight conveyor, with a belt that wanders all over the place!

The staright conveyor has crappy splices.

Cheers

LSL Tekpro ■

Have a read here.

http://www.fennerdunlopamericas.com/...ingFDA0105.pdf

The more you go beyond the 1/8" tolerance the more tracking problems you will experience. It basically comes down to what you are willing to live with in your system. Our standard is 1/8" tolerance off center. Others may be even tighter. ■

Originally Posted by Gary Blenkhorn

It sounds like you have a poorly designed system.

Enough said.

Except! Later on we are told that the belt capacity is 60 tph but it is running with 100 tph & there is spillage. Nothing new about that! ■

Originally Posted by meejay

Hello,

There is a belt conveying system comprised of five seperate belt conveyors in one of our fertilizer complex. The first one feeding the following one and so on. The throughing angle is 30 degrees. There is a spillage problem on both sides of these conveyors. I have examined the system and revealed the following points. I would be very pleased to recieve critics on each statement and explain if I am wrong.

• Improper chute design (which I think is the major problem). Suppose there is an imaginary line consising of the infinitesmal points which are the center of gravity of differential cross sectional areas of the material in fact. This line should overlap the centerline of the belt conveyor (which is another imaginery line passing from each center idler throughout the conveyor) in a stable operating belt conveyor. Somehow a proper chute feeds the following conveyor in a way to send the former imaginary line an inche away from the latter. The improper loaded belt reacts to overlap these two lines again and the chute will feed the raw material closer to the edge and this chain reaction will continue resulting in spillage.
• The belt speeds are not the same which causes overloading of specific belts in return.
• There are missing center idlers and frozen wing idlers. There are elevation differences between wing idler sets ranging from 0 to 2,5 cm. (0-1 in.)

There are two important questions

1. I also would like to know if there is a specific tolerance limit for idler sets concerning the elevation (between each idler set (2 wings+1 center) and with other idler sets). Should all the wing idlers on one side be at the same elevation if not what should be the maximum elevation difference? Should there be an elevation difference for the tracking idler sets?
2. The returning side of the belt is driven to a side of the conveyor system by a bend pulley. Will this cause any problem and what are the risks?

Thank you in advance.

Bend pulleys should be parallel and inline with return tollers. ■

Originally Posted by Gary Blenkhorn

Typically on any conveyor the centerline should not vary more than 1/8".

How come I've seen troughed belt conveyors with a curve in the horizontal plane??? ■

Originally Posted by designer

How come I've seen troughed belt conveyors with a curve in the horizontal plane???

Sure it can be done on a horizontal curve when it is designed to be on a curve.

But I am talking about a conveyor that is designed to be straight. ■

Originally Posted by Gary Blenkhorn

But I am talking about a conveyor that is designed to be straight.

Sorry Gary, I missed that bit in your response. ■