Ordinary rubber hardens, cracks and loses its bond to the fabric when it runs hot. Heat resistant covers are compounded to keep their strength and flexibility at temperature, and the carcass and skim are built to hold together under it.
The three heat grades
| Grade | Continuous material temperature | Typical duty | Standard |
|---|---|---|---|
| T1 | up to 100°C | Warm material, moderate heat | IS 1891 Pt 2 HR, DIN-T |
| T2 | up to 125°C | Clinker, sinter, hot ash | IS 1891 Pt 2 HR, DIN-T |
| T3 | up to 150°C | The hottest duties | IS 1891 Pt 2 SHR, DIN-T |
Choosing the grade
- Use the material temperature at the loading point, not the ambient temperature.
- Tell us the peak lump temperature as well as the average: a few hot lumps can be hotter than the bulk.
- Fine material lies flat on the belt and transfers heat faster than lumps; it can need the next grade up.
- Choose a thicker top cover (6 mm and up) so the heat does not reach the fabric.
Making heat belts last
- Keep the belt running: a hot load standing on a stopped belt damages it most.
- Avoid water quenching on the belt where possible; thermal shock cracks the cover.
- Store spare belts out of the sun and away from ozone.
Where heat resistant belts are used
- Cement clinker from the cooler
- Sinter and pellets in steel plants
- Hot ash and bottom ash in power plants
- Foundry sand and returns
- Fertiliser and chemical plants with hot product
- Coke and hot coal
Why ordinary belts fail on hot duty
Heat speeds up the ageing of rubber. An ordinary cover hardens and cracks, the cracks open to the fabric, and the skim rubber that bonds the plies loses its grip until the plies separate. A heat resistant belt slows all of this down by using compounds designed to hold their properties at temperature, tested by oven ageing.
Questions
What temperature can a conveyor belt handle?
A general purpose belt handles about 60°C. Heat resistant grades go higher: T1 to 100°C, T2 to 125°C and T3 to 150°C continuous material temperature.
Which belt is used for clinker in cement plants?
Hot clinker usually needs T2 or T3 heat resistant covers, depending on the clinker temperature at the loading point, with a top cover of 6 to 8 mm.
Need the belt chosen for you?
Send your conveyor, our engineers select the belt
Length, lift, width, speed, capacity and the material. We reply with the rating, covers and grade, a datasheet and a quotation, usually the same working day.