Air slide conveyor
Air slide conveyors are the ‘best-fit’ solution for many industrial circumstances.
Air slide conveyors provide some of the most efficient and practical methods of conveying bulk powder material. With some low-pressure air, an aeration bed, and a small incline (gravity), can convey hundreds of tonnes of products over long distances. Air slide conveyors can be used for cement, fly ash, and other powdery materials that are easy to fluidize. The air slide conveyor uses a high-pressure centrifugal fan as the power source so that the material in the closed conveying chute keeps fluidized and the inclined end is slowly moved. The main part of the Air slide conveyor equipment has no transmission part. It adopts a new type of air slide fabric, which is convenient for sealing operation and management. The equipment is light in weight, low in power consumption, large in conveying force, and easy to change the conveying direction.
Basic structural features of an air slide conveyor
Some of the basic structural features of an air slide conveyor system include:
- Section width and height of the aeration bed dictate the conveying rate
- Turning boxes (pots) are used to divert flow from one direction to another.
- Aeration cloth is generally woven permeable polyester
- Inspection ports provide access to visually inspect inside the air slide section.
Several points of how air works with the air slide conveyor system include:
- A fan or blower provides aeration air through the aeration cloth
- Weir plates used to adjust the aeration bed depth
- Air control valves are used to adjust the amount of aeration air being used
- Dust collection vents remove the spent air expended from the product during conveying
Typical example
A typical air slide installation in a cement depot will convey cement (bulk powder) some distance from a silo discharge. Ultimately, it discharges cement into a tanker via a loading chute.
Air slide conveyor and metal support sheet
Install a perforated metal support sheet under the air slide fabric. This provides stability and less movement of the fabric while conveying. This will extend the life of the cloth.
Work principle
On a permanent equilibrium, the angle of repose of bulk materials naturally achieves a constant slope from the horizontal plane.
To properly allow the transported material to flow, it was necessary to draw conveyor systems with a slope greater than the angle of repose of the material. These, however, have caused more complications, resulting in the invention of fluidized conveying systems. These are also known as air slide conveyor systems or air gravity conveyors.
The air slide conveyor is a metal box divided into two parts:
- The upper part, where the fluidized powder material is located
- The lower part, where the air is at a pressure between 0.5 to 5.0 PSA
- A porous air slide fabric membrane is located between the two parts of the housing.
The air thus passes through a false bottom or membrane made of a suitable porous material (polyester). This membrane extends over the entire length of the air slide.
The principle of operation behind an air slide system is driven by fluidizing air. After passage through the bed of material sliding over the membrane, the substance flows over the bed of material and is discharged through a suitable filtration unit.
Since the material is maintained by means of regular airflow, it flows freely down the slope, even when the inclination angle is relatively small.
The amount of air used is kept to the minimum necessary to reduce the interparticle force and the frictional forces between particles and surfaces of the inner channels, sufficient to allow the flow of material.
How to calculate
An air slide conveyor system dimensions include:
- Width: The width of an air slide conveyor system is calculated based on the capacity and the material density of the powder transported
- Length: The length of the air slide conveyor system does not have any specific limitation.
- The angle of inclination: The angle of inclination may vary depending on the type of material being conveyed. It is based on the principle that the more fluid the material is, the less the air slide conveyor needs to be inclined.
Works Cited: “UNDERSTANDING HOW AIR SLIDE CONVEYOR SYSTEMS WORK”, Pneuvay Engineering Pty Ltd, Visited 14 Aug, https://www.pneuvay.com.au/pneumatic-conveying/news/Understanding-how-air-slide-conveyor-systems-work/