What a Ø133 Conveyor Idler Set Is
A Ø133 conveyor idler set is a group of carrying or return rollers built around a 133 mm roller diameter. In a typical troughing arrangement, three rolls form a cradle that supports the loaded conveyor belt; in a return position, one or two rolls guide the empty belt. The 133 mm size sits in the mid-to-heavy range of idler diameters, so it is often chosen where belt widths and material loads call for more support than smaller rollers can provide. This article focuses on the Ø133 conveyor idler set itself, not on drive pulleys, tail pulleys, or bend pulleys, which serve different functions in the conveyor line.
Construction Details That Matter
A standard set usually includes the roller shell, shaft, bearings, seals, and end caps, assembled so each roll turns freely under load. The shell may be steel tube, nylon, ceramic, or rubber-covered depending on the duty. Bearing selection is matched to the load and speed; common bearing numbers include 6205, 6305, 6306, 6308, and 6310, but no single bearing is tied to one roller diameter. Sealing is critical in dusty or wet conditions, and the end cap design affects how well the bearing cavity stays clean.
Roll length is not fixed by diameter alone. For a three-roll troughing set, common roll lengths vary with belt width, trough angle, and set type. The table below gives reference examples, not universal specifications.
| Belt Width | Typical Roll Length (three-roll troughing) | Trough Angle Range |
|---|---|---|
| B800 | 315 mm | 20° to 45° |
| B1000 | 380 mm | 20° to 45° |
| B1200 | 465 mm | 20° to 45° |
| B1400 | 530 mm | 20° to 45° |
| B1600 | 600 mm | 20° to 35° |
These values are common examples; side rolls and center rolls can differ, and the final dimensions should always be confirmed against the conveyor design. A Ø133 idler set may also appear in two-roll or single-roll forms for specific transition or return positions.
Where Ø133 Idler Sets Are Used
Because of its larger diameter, a Ø133 conveyor idler set is often found in bulk handling operations where belt widths run from around 800 mm up to 1600 mm or more. It suits primary crushing circuits, stockyard conveyors, and main haulage lines in a quarry or aggregate plant. In a coal preparation plant or a power plant coal yard, the set helps carry a loaded conveyor belt steadily over long distances. The same diameter can be used on return runs with flat or V-return configurations, though those are separate idler types and not interchangeable with troughing sets.
When selecting a set, consider the belt speed, material lump size, and loading pattern. A heavy-duty application with sharp rock may call for rubber-covered rolls or impact rolls at transfer points, while a clean, fine material line may use plain steel rolls. The conveyor bracket and frame must match the idler set’s mounting dimensions; a mismatched bracket can cause poor alignment and premature wear.
Buyer’s Checklist for Ø133 Idler Sets
- Confirm the required roll length, shaft diameter, and bearing size against the conveyor drawing.
- Specify the trough angle (20°, 30°, 35°, or 45°) and whether a forward tilt is needed for belt training.
- Choose the roller surface (steel, nylon, ceramic, or rubber) based on material abrasiveness and environment.
- Check sealing and lubrication requirements for dusty or wet conditions.
- Verify that the set is compatible with the existing conveyor bracket and frame spacing.
For related conveyor components, you may also work with Rubber Conveyor Belt and conveyor pulley suppliers, but the idler set should be specified as a distinct item. A well-matched Ø133 conveyor idler set helps maintain belt alignment and reduce downtime in demanding industrial settings.
