Even brief periods of freezing conditions can have a devastating effect on rubber conveyor belts. When the ambient temperature falls below -0°C, rubber conveyor belts with multi-layer fabric and steel cord construction begin to lose their flexibility. As the temperature continues to drop, the rubber continues to lose flexibility and resistance to abrasion, impact and cutting. Eventually, the belt becomes so stiff that it cannot pass through or around the pulleys. The rubber belt covers and the rubber inside the carcass begins to break. Eventually, the belt will break because when the rubber freezes, it becomes so weak that it will shatter like glass.
For rubber conveyor belts, the actual temperature level that can be used to define "extreme cold" depends on the type of rubber (covering grade classification). For example, depending on the build quality, good quality abrasion resistant belts can typically withstand temperatures as low as -30 to -40°C without much trouble. However, other cover grades, such as those that are fire or oil resistant, can usually withstand temperatures as low as -20°C.
Even though the conveyor may only occasionally encounter temperatures below this, a wise strategy is to install a belt that is made of a specially manufactured rubber compound that can withstand extreme cold. If the minimum expected temperature is at a critical value, such as -15°C, there are other considerations, such as the wind chill factor and a belt that sits idle all night. During the day, friction between the rollers and pulleys helps to raise the temperature of the rubber. However, prolonged periods at rest in cold conditions can produce abnormally low temperatures in the belt and therefore lack the necessary elasticity and flexibility at start-up. What can also happen is that the drive cannot provide enough power, which can slip and damage the belt, or even eventually cut it.
There is no international test method to specifically determine the ability of a conveyor belt to operate in extremely cold conditions. Our lab technicians tested rubber belt samples at extremely low temperatures by using a liquid nitrogen freezer to literally test to the breaking point. The modulus of elasticity of the samples was first measured at an ambient temperature of 20°C. They are then placed inside the cabinet. The temperature inside the cabinet was then gradually reduced by 5°C. The modulus of elasticity of the samples was precisely measured at each stage to determine exactly when the drop in flexibility of the rubber became too great to determine its minimum allowable ambient temperature.
As I mentioned before, different rubber compounds designed to resist different needs (such as abrasion, fire or oil resistance) have different degrees of extreme cold resistance. This certainly applies to our line of cold-resistant rubber compounds. For example, our cold-resistant abrasion resistant rubber (Coldstar RAS) is designed to withstand temperatures down to -60°C, while other grades such as oil and fire resistant range from -40°C to -30°C.
To be fair, the market demand for cold resistant belts is the smallest of all belt types. This largely explains why it is difficult to find a conveyor belt manufacturer that includes specialized cold resistant conveyor belts in its product range.
However, at Huayue, it is part of our product range because we serve customers around the world who operate in a variety of extreme climates. This makes it imperative that we offer a truly comprehensive product range to meet the specific needs of all our customers, no matter where they are located.
Often, the various specialty chemicals and additives used to make rubber compounds that can withstand the specific requirements of oil, fire, heat and cold can negatively impact the ability of the rubber to withstand abrasive wear. In other words, oil-, fire-, heat- and cold-resistant belts typically have a short wear life. I am proud to say that this is definitely not the case with our special resistant belts, in fact quite the opposite.
When developing it, our rubber compound engineers came up with something very special. Not surprisingly, they insist that they did it on purpose, but regardless of the facts, it's still pretty amazing. The truth is that the abrasion resistance of our compounds is virtually unparalleled when compared to conventional abrasion resistant rubbers. The highest standard for abrasion resistance is DIN W, which requires a maximum loss of rubber during a 90 mm³ test. Under ISO 4649 / DIN 53516 test conditions, the average test loss of our belts is only 35 mm³.
Even under the harshest wear conditions, it falls into a completely different category, even in terms of providing a long wear life. So even if belts are not affected by extremely low temperatures, if wear is a problem, then maybe there is a "miracle" solution after all!
When evaluating offers for cold-resistant belts (and the accompanying technical data sheets), my advice can be summarized as follows.
1. Always ask potential suppliers for details of test methods and standards used to resist extreme cold.
2. Insist on a minimum level of wear resistance (according to ISO 4649 / DIN 53516) of less than 150 mm³.
3. When selecting any rubber conveyor belt, make sure that ozone and UV resistance (ISO 1431) are an automatic part of the specification.
If you are looking for manufacturers or suppliers of cold resistant conveyor belts, you can contact us for more information about price, specification, material, splicing, etc. of cold resistant conveyor belts.