Pneumatic conveying is the process of using compressed air to move bulk materials through pipelines from one point to another, for example from a truck to a silo or across an industrial facility. While that sounds pretty straightforward, in reality, it is not quite so simple. There are different pneumatic conveying systems using different air pressures, and choosing the right one depends on the material that has to be conveyed and the distance that needs to be covered. Picking the ideal pneumatic conveying system has very real benefits for businesses in terms of their investment and operating cost as well as their carbon footprint. The solution that is right for one application could be very inefficient for another.
Pressure conveying, which is also referred to as positive conveying, is the process of using compressed air to “push” a bulk material through a pipeline. For example, cement is dropped into a pipeline from a silo. There, at the starting point of the pneumatic conveying process, it is moved through the length of the pipeline or hose (and even some types of bends) by a compressor or blower. This compressor or blower can either be stationary or mobile. This method is particularly good for covering larger distances.
Vacuum conveying, which is also referred to as negative conveying, is the process of using compressed air to “suck” a bulk material through a pipeline. In this case the compressor or blower is placed at the endpoint of the process. One benefit is that there is no contact between the compressed and the material that is being conveyed, there is no contamination. In addition, the product is not exposed to the heat generated in the air compression process. However, the distance that can be covered with this method is limited.
A phase in pneumatic conveying refers to the way the material moves through the piping network. There are three different phases in pneumatic conveying: dilute (A), dense (B) and transient (C).
Pneumatic conveying is great for moving bulk materials, but, obviously, not all materials are the same. Understanding the requirements of the specific material you are conveying, will help you to safeguard the quality of your product and the efficiency of your process.