How is a conveyor belt supported and glided?

The entire range of simple belts, as well as the derived (non-standard) types, can be transformed into composite belts when the following accessories are used in their construction: Side fins: to prevent the product from falling off the side of the belt, and can be of variable shape and height (type C.A-L, C.A1-L, etc.). Transverse strips: to retain the product when the belt is working on an inclined plane. Normally, angles are used that are fixed to plates by means of screws or welded directly to the belt mesh. In principle, their height has no limitation (types C.A-T, C.A1-T, etc.). The belts can be manufactured with fins and strips (type C.A-L-T, C.A1-L-T, etc.). Side chains: to facilitate the dragging of the belts and ensure good traction, preventing the mesh from suffering wear due to the dynamic movement of the belt. The most standard pitches are used, such as 9.52 mm, 12.70 mm, 15.87 mm, 19.05 mm, 25.40 mm, 38.10 mm and 50.80 mm (types C.A..., C.A1..., etc.). However, the belts can be made to the measurements required by our customers, with the chain being attached to the belt at each pitch or every N pitches. Belts with chains can also be built with side flaps and cross bars (types C.A...L, C.A1...L, C.A...L-T, C.A1...L-T, etc.). (...) The chain pitch must be placed in the ellipsis of the belt types. In addition to these usual accessories, composite belts can be manufactured with continuous or perforated sheet metal bars inside the coils, U-shaped strips, raised coils, fork-shaped rods, etc. Our Technical Department can study and carry out any transport that our clients wish to carry out, whatever its level of complexity.

How to install a conveyor belt?

It is always advisable to carry out maintenance on the conveyor before installing a new belt. To do this, the following points must be observed: Uncouple the old belt from the lower part of the drive cylinder, tie a cable to its end and as the belt is removed, the cable will be introduced through the conveyor. This cable will be used to introduce the new belt. Check all the guides and cylinders of the conveyor (drive, return, tensioner, supports, etc.). All of these cylinders must form a right angle with respect to the middle line of the conveyor and be perfectly parallel to each other. Check the supports or sliding track of the belt. There must be no sharp edges or elements that could rub and wear out the belt. Once the conveyor has been checked and cleaned, we will proceed to introduce the new belt using the cable that we previously placed on the conveyor when the old belt was removed. If the conveyor is not checked, the belt can be changed by simply joining the end of the old belt to the new one and as the old one is removed, the new one will be introduced. Virtually all belts have a direction of travel, note the direction of travel before placing the belt on the conveyor.

How to load and start a conveyor belt?

Loading the belt Loading should be done as evenly as possible. A belt with an even load distributes wear along its underside and prevents distortions that could shorten the belt's life. Starting up the belt For conveyors operating at room temperature, the belt will be pre-tensioned and speed will be increased slowly until reaching working speed. At all times it will be observed that the belt maintains its trajectory without rubbing on one side or the other. Never try to align or position the belt by hitting the sides; alignment will always be done by correcting the cylinders (drive, return, supports, etc.). A high temperature belt should "roll" in a similar way to any other precision part. The oven should be brought to working temperature at a speed not greater than 148° C per hour. Once the operating temperature has been reached, the strip should be run for approximately 5 hours without load to ensure proper seating of the strip elements (coils and rods). Temperature changes have an invariable effect on the breaking properties of the strip. Therefore, during this period, careful attention must be paid to adjusting the stroke when necessary. During the break-in period, the strip must be stress-relieved to ensure maximum working life. The increase in service life by proper stress-relieving at the proper temperature is achieved by the fact that annealing at the proper temperature prevents excessive grain growth. Stress-relieving procedures can be summarized with the following suggestions: For alloys operating at 925° C or higher, the stress-relieving treatment should be long enough so that each portion of the strip operates at 925° C for at least one hour. For alloys operating at 898° C or less, stress-relieving treatment should be performed at 28° C above normal temperature for a period of time sufficient to allow each section of strip to reach the stress-relieving temperature for at least one hour. Once stress-relieving treatment has been performed, the furnace temperature should be increased at a rate of 164° C per hour until the final operating temperature is reached. At this time, the strip should run a minimum of 5 hours without load. High-temperature strips generally have a predetermined, measurable amount of tension before stress failure occurs. Intentionally tensioning the strip only saves a few hours of maintenance time at the cost of greatly reduced strip life.

How to extend the life of a conveyor belt?

Certain precautions must be observed when the belt is stopped, to obtain maximum service life: A .- The belt must be stopped with the atmosphere running. B .- High temperature furnaces which have a counterweight or air cylinder type of intake at the discharge end must have their back tension reduced. Otherwise, the back tension is transmitted along the belt so that the tension in the hot zone may be greater than when the belt is loaded. C .- A high temperature belt must be kept in motion, if allowed to stop, it tends to weld itself to the furnace floor and serious damage results when restarted. D .- Regular checks of the belt's course must be made during the unloaded period, since temperature changes frequently induce changes in its stroke. In this section, "BELT STOPPING" is understood as stopping when the belt is not loaded.

Conveyor belt technical information

Sliding supports and drive haulage systems

All the simple conveyor belt range, besides the derived types (not standard), may become composed conveyor belts when the accessories hereunder make part of their construction:

Side wings: to prevent the product from falling over the sides of the belt, and its shape and height can vary (types C.A-L, C.Al-L, etc.).
Crosswise strips: to hold the product whenever the belt operates on inclined planes. Angle bars fastened to flatbars by screws or directly welded onto the belt mesh are commonly used. In principle, their height has no limitations (types C.A-T, C.Al-T, etc.). The belts can be also manufactured with wings and strips
(types CA-L-T, CA1-L-T, etc).
Side chains: to ease belt haulage and ensure proper drive preventing the wire mesh from being subject to the wear and tear resulting from the dynamic motion of the belt. The most standard pitches are used, such as 9.52 mm, 12.70 mm, 15.87 mm, 19.05 mm, 25.40 mm, 38.10 mm and 50.80 mm (types C.A ... , C.AL., etc.). However, the belts can be manufactured at the size our customers may require, by linking the chain to the belt at each pitch or at N pitches. The chain belts can be also manufactured with side wings and crosswise strips (types C.A1..., e.A1...L, C.A ... L. .. T, C.A1. .. L. .. T, etc.). ( ... ) Fill in the chain pitch on the belt type suspension points.

Besides these usual accessories, composed conveyor belts can be manufactured equipped with continuous or perforated sheet flatbars inside the spirals. U-shaped strips, high spirals, fork-shaped finished rods, etc. Our Technical Department can study and execute any handling our customers may require, no matter how complex it may be.

Belt installation

It is always advisable to carry out some conveyor maintenance before using the new belt. For that purpose, we observe the following points:

On completion of checking and cleaning the conveyor, we will proceed to introduce the new belt by using the cable that we have previously placed in the conveyor when removing the old belt.

If no maintenance is required, we may just change the belt by joining the new belt to the old one when removing it.

Almost every belt has a running direction, so this must be taken into consideration when placing the new belt into the conveyor.

Product load and belt starting

Product load

The product load on the belt must be as uniform as possible to evenly distribute the weight on the lower side, thus preventing distortion and premature belt failure.

Belt starting

For conveyors that operate at an ambient temperature, we will pre-tense the belt and gradually the speed until reaching the working speed. We must observe that the belt remains straight, with no friction on the sides.

We should never line up or place the belt by scraping along the edges. The lining up must be done by correcting the cylinders (driving, return, supports, etc.).

A high temperature belt must run in a similar way to any other precision part . The oven must increase its temperature at a speed not higher than 148ºC per hour. Once the working temperature has been reached, the belt must work about 5 hours without any load to ensure the correctly settling-down of the belt elements (spirals and cross bars). Changes in temperature affect the breaking properties of the metal and close attention is needed to determine any belt adjustment that may be required during this period.

During the rolling period we must eliminate any tension in the belt to ensure its maximum working life. In addition we avoid any excess in the growth of the grain by annealing it an adequate temperature.

The process of avoiding the tensions may be further achieved with the following two suggestions:

For alloys that work at 925ºC or over the treatment of tension elimination must be quite long, so that each section of the belt should work at a minimum 925ºC for an hour.
For alloys that work at 898°C or under the treatment of tension elimination must be done at 28ºC
above the normal temperature for sufficient time for each section of the belt to reach the temperature of tension elimination for at least one hour.

Once the tension elimination treatment is completed, we continue to increase the oven temperature at arate of 164ºC per hour, until the final working temperature is reached. At that point, the belt must run a minimum of 5 hours without any load.

Generally, the high temperature belts have a centain amount of tension predeterminated before an failure in the tension occurs. The intentional tension of the belt only saves so me hours of maintenance at the expense of the belt long term durability.

Stopped belt

When the belt is stopped the following precautions are essential, in order to obtain the maximum service life:

A .- The belt must be stopped with the operational temperature working.
B .- The belt tension must be reduced to the minimum needed to engage the drive sprockets properly or adjusted according to the manufacture's documentation. This applies in particular for high temperature ovens, which are equipped with a counterbalance or air cylinders fot the belt take-up at the extreme unloading end. The high counter tension conveys along the belt in such a way that the tension in the heated area may be bigger than where the belt carries the load.
C .- A high temperature belt must be maintained in motion, if stopped it may weld to the support of the oven and cause serious damage when restarted.
D .- Regular tests regarding the direction of the belt must be carried out without load, as the changes of temperature induce quite often to changes in the run.
In this chapter, "BELT STOP" stop is understood without any load on the belt.

Sliding supports and drive haulage systems

Drive haulage systems

Thrust haulage (high temperatures)

Belt installation

Product load and belt starting

Stopped belt

All about our conveyor belts