Pneumatic conveying represents a technique for transferring materials such as powders, dry bulks, and granules within industrial facilities. This method involves moving these materials through enclosed pipelines, utilizing a force typically generated by a gaseous airflow to propel them to their intended location.
The pneumatic conveying system encompasses several key components. An air mover, commonly referred to as the motive source of air, functions as either a blower or a fan. Additionally, a feeder or loader is essential for introducing the materials into the system. The conveying line itself, a termination receptacle or material receiver, and a dust collection system are also integral parts of the setup.
A wide array of materials can be conveyed pneumatically, provided they are relatively dry. Examples abound, including flour, plastic pellets, sand, cement, and numerous food products, chemicals, and minerals. However, materials in paste or slurry forms are incompatible with pneumatic conveying.
Furthermore, pneumatic conveying systems are categorized into two types: dilute phase and dense phase. For a more comprehensive understanding of conveyor systems, you may refer to this article.
How A Pneumatic System Works
Performing any task necessitates a specific form of energy, and this principle equally applies to pneumatic conveying systems. To facilitate the transportation of materials within these systems, energy is indispensable. In the context of pneumatic conveying, this energy is furnished through a pressure differential, quantified in pounds per square inch. Furthermore, the system’s operation involves an airflow measured in cubic feet per minute.
The air pressure within the conveying line of a pneumatic system undergoes modification via an air mover. This device can either create pressure or induce a vacuum, depending on its strategic placement within the system. If positioned at the inception point, the air mover propels air through the system, resulting in pressure-driven operation. Conversely, when situated at the termination point, it draws air through the system, facilitating vacuum-based operation. Effective material transportation within the system hinges on the meticulous control of both pressure (or vacuum) and airflow.
Advantages Over A Mechanical Conveying System
Typically, a mechanical conveying system operates along a straight path with minimal changes in direction. Each directional alteration necessitates a separate drive and motor. Moreover, the system is predominantly open, making it prone to dust generation. Frequent maintenance is also required due to the numerous moving components involved.
Furthermore, mechanical systems consume considerable space. Conversely, pneumatic conveying systems offer several advantages. They are straightforward to install, maintain, and operate. Utilizing compact pipelines of small diameters for material transfer, these systems can be configured to seamlessly integrate with existing equipment. This provides them with a versatile layout and minimizes space utilization. Being fully enclosed and having limited moving parts, pneumatic systems necessitate minimal maintenance. Consequently, concerns related to dust, contamination, and air quality are reduced.
Disadvantages When Compared To A Mechanical Conveying System
A pneumatic system generally demands more horsepower and, subsequently, greater energy for operation compared to a corresponding mechanical system. This is primarily attributed to the substantial power consumption involved in altering air pressure, making it less efficient than a mechanical system in this context.
Additionally, such a conveying system necessitates a significantly larger dust collection apparatus than a mechanical one. The rationale behind this is the necessity to separate the conveyed material from the transporting air at the termination point.
Moreover, pneumatic conveying systems are ideally suited for bulk and dry materials. Transporting other types of materials, such as those with large particle sizes or high bulk densities like rocks and gravel, can be challenging within such a system.
Materials like slurry, sticky substances, and those in paste form are also unsuitable for pneumatic conveying systems. They are more easily transferable using a mechanical system specifically designed to handle such materials.
Applications of Pneumatic Conveying Systems
Some common ways to use this kind of conveying system include:
Feed lance injection in steelmaking as well as in non-ferrous metal smelting.
Recycling
Burner feeding using alternative fuels and combustible dust in cement industries.
Used in friable products like carbon black prills and pet food post-extruders.
How To Select A Pneumatic Conveying System
When selecting a pneumatic system, the foremost consideration is the nature of the materials that will be conveyed. This entails examining their size, shape, moisture level, bulk density, fragility, and abrasiveness. Additionally, factors such as static electricity, hygroscopicity, toxicity, melting point, and explosiveness must be taken into account.
Secondly, you must assess how well the system aligns with your plant’s environment or location. This involves evaluating the length and intended routing of the system. Considerations should also be given to the ease of accessing components for maintenance purposes.
Thirdly, it is crucial to consider the required material transport rate to meet your operational expectations.
Conclusion
Pneumatic conveying comes with both advantages and disadvantages when compared to mechanical systems. Nevertheless, it provides the best method for transporting some materials.
If the materials you have to work with are mostly dry, powdery and heavy bulk, you will do well to use this system. It is easy to install and maintain as well as flexible.