Spiral elevators are coil shaped vibratory conveyors which are used to elevate or softly de-elevate material.
Common applications include:
- Material that is too abrasive for screw conveyors.
- Another process such as cooling or heating is required during transportation.
- Easy access for cleaning is required.
- Hygienic surfaces are required.
Construction materials for spiral elevators include mild or stainless steels. Hard wearing metals such as bisalloy or hardox can also be used in abrasive applications.
Drive systems can be either direct drive or sub resonant. Direct drive systems are better for smaller units with lighter loads while sub resonant tuned equipment is used when there is a requirement for heavier duties. Sub resonant systems allow a feed rate adjustment via an electrical control.
Due to a small horizontal footprint and large travel distance, vibratory spiral elevators are often used to either heat or cool material. Holes can be drilled in the central tube and hot (or cold, depending on process) air can be passed through to assist the product to reach desired temperatures.
Liners can be installed on the curved trough surfaces to achieve different goals:
- Polyurethane liners to provide protection from wear and prevent material from sticking.
- Teflon can be sprayed which also provides wear protection and minimises material adhesion.
- Hard wearing steels such as bisalloy or hardox can be bolted or welded to an extremely hard wearing surface.
- Rubber, either securely fixed or live, will greatly reduce the amount of material that will stick to the trough surface.