What the Ø133 Conveyor Idler Is
A Ø133 conveyor idler is a carrying or return roller built with a nominal shell diameter of 133 mm. It sits beneath or above the conveyor belt, supports the loaded belt line, and lets the belt travel with low rolling resistance. In a coal preparation plant or a cement clinker line, this diameter is often chosen where belt loads are moderate to heavy and where a larger roller body gives better stiffness and bearing life than smaller shells. The same product is also called a 133 mm diameter idler roller, and both names describe the same item.
This is a belt idler, not a drive, tail, or bend pulley. Those pulleys transmit power or change belt direction at the ends of a conveyor; the Ø133 conveyor idler only supports the belt along its run. Confusing the two leads to wrong spare parts and wrong maintenance plans.
Construction and Surface Options
The roller usually consists of a steel tube shell, a shaft, bearing housings, seals, and end caps. Common bearing sizes used in this class include 6205, 6305, 6306, and 6308, matched to the shaft and load by the manufacturer rather than fixed by belt width alone. Sealing quality matters in dusty sites such as a limestone quarry or a sinter plant, because fine grit entering the bearing is a leading cause of seizure.
Shell surfaces vary with the duty. Plain steel suits general carrying runs. Rubber rings are used on buffer idlers at loading points to absorb impact. Nylon or ceramic covers may be selected where sticky material or abrasion is a concern. The table below shows typical reference values; confirm actual dimensions with the supplier.
| Parameter | Common Reference | Notes |
|---|---|---|
| Nominal diameter | Ø133 mm | Shell outside diameter |
| Belt width | B800, B1000, B1200, B1400 | Often used in this range |
| Trough angle | 20°, 30°, 35°, 45° | Three-roll sets common |
| Roller length | 315 mm to 530 mm | Varies with belt width and roll position |
| Bearing | 6205, 6305, 6306, 6308 | Selected by load and shaft design |
| Surface | Steel, rubber ring, nylon, ceramic | Rubber rings for impact zones |
Where It Fits on the Conveyor
On the carrying side, Ø133 conveyor idlers are frequently arranged as three-roll troughing sets with a 30° or 35° trough angle, which keeps bulk material centered on the belt. A two-roll set may appear on narrower belts or in transition zones. On the return side, flat or V-shaped return idlers support the empty belt.
Impact and buffer idlers with rubber rings are placed under the loading chute in a crushing and screening circuit, where falling rock would otherwise damage a standard roller. Self-aligning idlers, including friction and tapered types, are used on long runs to correct belt drift. These are different functions, so a buffer idler should not be treated as a substitute for a troughing idler in the main carrying run.
Selection Points for Buyers
- Match the roller length to the belt width and the roll position; side rolls and center rolls can differ.
- Check the shaft diameter and bearing seat against the existing conveyor bracket, not just the shell diameter.
- Confirm the trough angle and idler set form (single, two-roll, or three-roll) before ordering.
- Specify the surface type for impact, abrasion, or material buildup conditions.
- Ask for seal type and lubrication details, especially for washdown or high-dust environments.
A Ø133 conveyor idler is a practical mid-size roller for B800 to B1400 belts in aggregate, power, and bulk handling service. Correct matching of diameter, length, bearing, and bracket keeps the conveyor belt running smoothly and reduces unplanned stops.
