What are Air Slide Belts?
Air Slide Belts (also known as Air Slide Conveyor Belts, and Pneumatic Conveyor Belts) are a type of conveyor belt that is used in dry solid powder conveying. This form of transportation is referred to as ‘Pneumatic Conveying’ whereby pneumatic conveyor systems cover long distances and transport materials from one point to another using air-activated gravity.
As a result, the belt requires a level of air permeability to allow the the air activated gravity technique to push air up and through the conveyor belt, allowing the power to transport through the conveying system from point A-to-B.
What are Air Slide Belts Made from?
Air Slide belts can be made from a number of materials in combination. However, some belts are made from 100% polyester or nylon. The main raw materials that air slide conveyor belts are made from are usually; nylon, polyester, P84 Polymides, or Nomex.
The best air slide belts are abraison resistant, rot and mildew resistant, while also being able to be used in temperatures ranging from 30’C to 150’C.
A good air slide belt manufacturer will produce a belt with materials that reflect the requirements of the solution. Each material can be woven to a required air permeability, depending on the ‘holes’ from which the low-press air needs to be filtered through the belting material.
Typically, these types conveyor belts are solid woven using the warp and weft threading technique. However, should requirements need a different weave, manufacturers can change the weave to suit the solution.
The belt can vary in width from between 150mm to 16500mm, again depending on the solution requirement. Additionally, the thickness of the ply from which the belt is woven can range from 4mm to 8mm depending on the requirement.
The Process of Fluidization
The conveying solution itself uses an enclosed conveyor system, which ensures no raw material is left behind, nor does it fall off the conveyor belt. All of the required powder is transported from one area to another using a low-pressure air flow from underneath the conveyor belt.
During the conveying, the powder material is put into a porous state (pulverized) within the ‘fluidizing beld, before being transported through the pneumatic conveyor and reaching the required destination.
The air-activated gravity of the air slide conveyor belt, and slope from which the system is manufactured to, allows the material to flow and move through the conveyor chute in a fluid fashion.
The belt itself sits within the middle of the pneumatic conveyor, in the chute between the powder fan and the air chamber. This is where the fluidized powder moves in a liquid fashion through the conveyor belt part of the system.
The type of fluidizing beds and pneumatic transport may vary depending on the material being passed through the pneumatic conveyor.
Different Fluidizing Beds
Bed fluidization can be both solid and fluid form (gas or liquid). Fluids flowing through a layer of bulk solid at a ‘fluidzsation velocity can loosen the individual particulates to ensure they enter a ‘suspended’ form. This is how a fludized bed is created and is aptly named ‘fluidization’. The flow of powder naturally acts like that of fluid to create this form and bed ready for transport.
If the velocity changes to become more excessive, particles are discharged into the pneumatic transport process.
Typically, there are three forms of fluidized beds that may occur during the fluidizing process. These are:
Homogeneous Fluidized Bed
A homogeneous bed is the name given to describe a fluidized bed that reflects the velocity increase of the fluid creating a balanced dilation of even distribution across the base layer.
Inhomogeneous Fluidized Bed
The inhomogeneous bed is the name given to describe the a fluidization process that results in heavier particles within the lower area of the fluidized bed. If gases are used as the ‘liquid’, bubbling occurs, which bursts at surface level, givnig off a look of boiling liquid within the fluidized bed.
Channeling Fluidized Bed
When finer grain bulk powder is the solid form being transported, the formation of a fluidized bed may not occur. This is due to the particles adhering to each other and natural flow channels being formed. Therefore, in order to create a fluidized bed, manual stirring is required.
Pneumatic conveyor systems are the medium for transporting the bulk powder through the conveyor system.
Traditionally, a pneumatic conveying system uses three core elements; a fan, a conveyor belt system, and a dust separation unit. The way the bulk powder is transported can be either horizontally, vertically and in a large amount of instances, on an incline.
Typically, there is a compression unit and suction unit used to pull or push the bulk powder through the pneumatic conveyor line. This is dependent on the phase of transport being used. There are two key forms of pneumatic conveyors; Dense Phase and Dilute Phase.
The Efficiency of Air Slide Conveyor Belts
Air slide belts are highly regarded due to their efficiency within industrial conveyor systems.
These conveyor belts can reach up to 100’s of meters in length, and use a low-maintenance single power source, which means running costs and manpower remain low. As the air slide conveyor belt sits within an enclosed system, there is only a requirement for one blower (fan), which sufficiently helps blow the air from top to bottom of the system. This makes the air slide belt extremely economical and also environmentally friendly.
Additionally, due to the way the system is bolted together, the solution is dust tight, which makes it very friendly to the environment.
Furthermore, the air-activated gravity is the only moving part of the conveyor belt (unlike conveyor belts used in biscuit manufacturing), which makes noise pollution for this belt minor. Traditionally, the system is attached to the ceiling, which allows for maximum floor space underneath, and the belting system is usually placed in a quieter part of the factory, which makes noise pollution even more minimal.
Air Slide Cloth Air Permeability
Air slide cloth needs to have a high level of air permeability. Depending on the materials tensile strength, the need penetration of the cloth, which in turn, impacts the whole creation within the weave of the air slide cloth. This, however, ensures increased strength when conveying heavy loads across a air fan system.
Depending on the air slide belt material combination the air permeability will have a higher propensity. For example, a polyester and nomex combined solid woven air slide belt will have both a higher puncture index from needle penetration and higher air permeability to that of polyester air slide belt alone.
Key Characteristics of an Air Slide Conveyor Belt
When searching for an air slide conveyor belt for your bulk powder handling system, there are a few key characteristics required to ensure your pneumatic conveyor system is treated with the air slide belt it needs.
Firstly, the temperature conditions that an air slide belt can withstand are key. Usually, in pneumatic conveying, the fluidized powder that is being transported is extremely hot and therefore an airslide conveyor belt that can withstand temperatures of up to 200’C is imperative. This is key characteristic of a polyester air slide belt and why polyester is a filament used in most air slide belting systems.
Additionally, due to the type of material being transferred, the propensity for potential ‘wear and tear’ is high. Using a polyester and nylon combination combats potential abrasion and tearing.
Finally, it’s important that your air slide cloth is very permeable and doesn’t trap dust. This is naturally, an obvious requirement, but can be over looked in lieu of searching for air slide cloth that fits the above requirements. A cloth material that doesn’t clog and consume all dust, but is easy to dust off will ensure a longer living air slide belt for your pneumatic conveyor system.
Air Slide Belt Manufacturers
Finding air slide belt manufacturers is easy, as long as you are aware of what you’re the requirements for the your conveyor solution.
Traditionally, air slide belt manufacturers are found within India or the UK, and a great conveyor belt manufacturer will look to provide an on-site review of your situation to ensure that the right bespoke belting solution is provided to you the client.