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PTFE Coated Lightweight Belting What is PTFE? Conveyor belting coated with polytetrafluoroethylene has a small, though important share in the market for lightweight belting. PTFE is also sometimes called Teflon, which is a trademark belonging to DuPont. The generic name of the material is PTFE. If a product if specific, you should check with the supplier before it is promoted as Teflon. In this article, the generic name will be made use of. PTFE belting: Where is it used? Lightweight belting coated with PTFE has many applications. Given below are some questions. If your answer to any of these questions is yes, then you may have a need for a PTFE coated belt. •

Is the process hot? Most PTFE belts can tolerate service temperatures of 500F. If the belt is properly designed, it can tolerate even higher temperatures.

Is the belt making direct contact with food? PTFE belts can be used to process and cook foods, without making use of a tray or a pan. This also includes cold processing.

Do you have a need for a non stick surface? Rubber and hot plastic when moved through an oven may need non stick surfaces when they exit the oven.

Is it a chemically aggressive process? PTFE is a very inert material. It doesn't contaminate or react with the conveyed product.

Will the oven be RF heated or microwaved? Fiberglass coated with PTFE is transparent to RF heating, dielectric heating, and microwave energy.

Will the product be belt-heated? Many non-mesh belts can slide over sources of heat such as hot plates. The heat can reach the product only by passing through the belt. To pass the heat faster, you need a thin belt. Some belts coated with PTFE will be 0.003 inches thin.

Will the oven circulate hot air? If the oven requires a high volume of air, then there are many open mesh belts coated with PTFE available.

Is there a need for a surface with low friction? PTFE belts can be very slippery.

Does the oven use UV curing? PTFE can resist UV light degradation very effectively.

When is PTFE belting to be avoided? PTFE properties can be useful in many cases. But there are some places, where PTFE belting is not very well-suited. Some applications are mentioned below. •

Inclined transport: Inclines should not contain slippery surfaces and PTFE is very slippery.


Contact with tobacco: Wherever the tobacco is in direct contact with the belt, PTFE should be avoided.

Power transmission: Power transmission requires a different kind of belt. PTFE belting is for lightweight transport.

Abrasive applications: PTFE is made of soft plastic. When transporting products like sand, stone, PTFE is easily damaged.

Gamma food sterilization: When exposed to gamma rays, PTFE breaks down.

Why is belting with PTFE different? Knowing how PFTE belting differs from normal belting can be lead to good performance and proper application. Elongation/Stretch Fiberglass belts coated with PTFE will rarely stretch, leading to a dimensional stability that is excellent. But because they hardly stretch, you will have to consider carefully how you will guide the belt. Crowned pulleys will not work with fiberglass belts coated with PTFE. Adjusting the take-up roller manually will also not work. If the belt is under four feet wide, the belt can be tracked with a variety of edge guides. For more details, contact your supplier. Active tracking systems can help you track belts that are more than four feet wide or those moving at high speeds. Such systems will have steering rolls and edge sensors to center the belt on the machine. Substrate Fiberglass is a woven fabric that is most frequently used as a substrate for coating the PTFE. Fiberglass is economical and will withstand high temperatures required to coat PTFE. But note that fiberglass leads to a more fragile belt. When the machine is designed, special considerations must be made to avoid damage to the belt. Occasionally, some other fibers are used. These include Nomex, carbon fibers, and Kevlar. Slippery Both faces of fiberglass belts will be coated with PTFE. The result is a belt that will easily slide on the support structure of the machine. The product conveyed on the belt will also slide easily and can be removed with ease when the process ends. The slippery surface means special attention is to be given when the guiding rollers and drive rollers are designed. Thickness Fabrics coated with PTFE are very thin. Among PTFE coated belts, the thickest ones are only about 0.040 inches thick, while the thinnest could be as thin as 0.003 inches. When there is a need for thermal


transfer through the belt, a thin belt is required. A thinner belt means more speed and higher production. But the thinness of the belt also makes it more fragile. Thin belts also have another problem. They cannot be put back on track , just by prodding the belt's edge. Design A successful process is mainly made of three steps. The first one is - the belt is to made from the right material. The second step entails designing/fabricating the belt. The design and the selection of the edges and seams are important for success. There are many edge and seam selection choices available. The machine design is the third step. A new design for the machine or the process should be done after taking the belting supplier into confidence, early in the design process. Factors that affect machine design are given below. • • • • • • • • • •

What type of seam is needed? How is belt is going to be tensioned? How will the belt be driven? How is the belt going to be supported? What process will the belt handle? How fast is the belt going to travel? How is the belt going to be tracked? Is it possible to put the belt on endless? How is the product going to be put on the belt and later taken off? What is the maximum temperature for the process?

PTFE belting and the future Belting coated with PTFE has been around for more than forty years. In this time, some new processes have come up that use PTFE coatings. Some trends that you should watch out for are mentioned below. Energy saving: PTFE belting is lightweight and can resist high temperatures. It is replacing belts with open meshes, heavy metals, etc in industries. Further, green movements have given an impetus to PTFE belting. Recycling is creating opportunities for PTFE belting also. Some new polymers can be best made use of in processes with high temperature which PTFE belts can withstand. Non garment laminators: These laminators are similar to the fuse presses that were being used earlier, but they are bigger. They are being used to press materials for medical products, automotive interiors, paper products, flooring, solar power equipment, etc. All in all, the future looks bright for PTFE belting.

www.beltpower.com


Ptfe coated lightweight belting  

Further reading into lightweight belting coating.

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