What the NN400 Conveyor Belt Is
The NN400 Conveyor Belt is a nylon fabric-reinforced rubber belt with a nominal tensile strength of 400 N/mm. In the NN series, the double N stands for nylon warp and nylon weft, giving the carcass high strength and excellent resistance to fatigue. This belt is a workhorse in bulk material handling, commonly found in mines, coal preparation plants, cement works, power stations, and sand and gravel yards. It is often referred to simply as an NN400 belt or a nylon conveyor belt of 400 grade.
Construction and Key Components
The belt is built around a nylon fabric carcass, usually available in 2 to 6 plies depending on the required strength and the demands of the conveyor system. The carcass is protected by rubber covers on both the top and bottom. Common cover thickness combinations include 3+1.5 mm, 4+2 mm, 5+2 mm, 6+2 mm, and 8+3 mm. The top cover faces the material and is often selected for abrasion, heat, oil, or flame resistance, while the bottom cover runs over the idler rollers and pulleys.
Edge construction and skim coats between plies help prevent ply separation and edge fraying. The belt is vulcanized into a solid, flexible slab that can trough well on idlers and track smoothly over pulleys. The nylon carcass also gives the belt good flexibility and impact resistance, which is valuable when loading lumpy material at a transfer point.
Typical Applications
Because of its strength and fatigue resistance, the NN400 belt suits medium-duty to heavy-duty conveying. In mining and coal handling, it may carry run-of-mine material or washed coal. In cement plants, it can transport clinker, limestone, or additives. Power plants use it for coal and ash handling, while sand and gravel operations rely on it for aggregate transport. The belt also works well on stackers, reclaimers, and long overland conveyors where the belt must flex repeatedly around pulleys.
Specifications and Options
Buyers should specify the belt grade, width, cover thickness, and any special properties. Below are common reference values; actual supply depends on the manufacturer and the conveyor design.
| Parameter | Common Options |
|---|---|
| Grade | NN400 (400 N/mm) |
| Belt width | B500, B650, B800, B1000, B1200, B1400, B1600 |
| Cover thickness | 3+1.5 mm, 4+2 mm, 5+2 mm, 6+2 mm, 8+3 mm |
| Carcass plies | 2 to 6 plies, depending on design |
| Special properties | Flame retardant, antistatic, heat resistant, oil resistant, wear resistant, cold resistant, acid and alkali resistant |
| Surface forms | Plain, patterned, chevron, corrugated sidewall |
Note that belt width does not dictate a single pulley diameter or shaft size; those are determined by the conveyor designer based on tension, load, and space. Drive pulleys, tail pulleys, and bend pulleys each serve different roles and are not interchangeable.
Buyer Checklist
- Confirm the required belt grade and safety factors with the conveyor designer.
- Select cover thickness and rubber quality for the material being carried.
- Check compatibility with existing idler rollers, conveyor pulleys, and conveyor brackets.
- Consider environmental conditions such as temperature, oil exposure, and fire risk.
- Plan for proper storage, splicing, and maintenance to maximize service life.
The NN400 conveyor belt is a versatile and reliable choice for many industrial conveying tasks. Matching it correctly to the system and the material is the key to efficient, long-term operation.
