Pneumatic conveying

In the “dilute phase”, the concentration of material is relatively low. The material is mixed with a large amount of air, resulting in a dilute mixture. This phase is characterized by high air velocity and low material-to-air ratio. The material is typically suspended in the air stream and conveyed as a turbulent flow. Dilute phase conveying is suitable for light, non-abrasive materials over long distances.  

At dilute phase, the medium is sent through a pipeline at a relatively high speed, as the particles must be airborne. Dilute phase transport can be performed with either vacuum or pressure. When vacuum is used, it requires that the pressure drop in the piping does not exceed 400-500 mBar, while a pressure system can work with a pressure loss of up to 900-1000 mBar.

Dilute phase conveying is characterized by the following:

• Used for the transport of materials that can withstand transport at high speeds
• Used for short pipe strings of up to 50 m
• Handles mass flow of bulk material from 0.5 t/h to 50 t/h
• Air/Material speed of approx. 20-32 m/s

Dilute phase is an energy efficient form of transport under the above conditions. Furthermore, the costs for blower, piping and filters for a dilute system are relatively low as long as the distances are kept short.

If the transport distance is increased, this form of conveying becomes more energy demanding as the pressure drop in the piping increases.

In “dense phase”, the material is conveyed at a lower speed using compressed air. The dense phase system is suitable for longer pipelines, and the transport speed is only 3-8 m/s. This means significantly less wear and tear on pipes and pipe bends, which results in savings for the customer, due to less downtime and reduced costs for replacing pipes and pipe bends.

Dense phase transport is also more energy efficient for transport over long distances. The high energy efficiency arises because large quantities of material are conveyed using a relatively small amount of air.

Compared to the cost of the blower and pipes that must be used for Dilute phase transport, the costs of a Dense phase system become relatively low when the transport distance is increased.

Dense phase systems can be used for the conveying of many different products, from wood chips to flyash.

Dense phase conveying is characterized by the following:

• Very gentle on the material being transported
• Transport over long distances, up to 1500 m
• Mass flow of bulk goods from 0.5 to 150 tons/h
• The air and material speed is approx. 3-8 m/s, depending on the particle size
• Is suitable for conveying of abrasive materials

Efficiency and Speed: Pneumatic conveying systems are highly efficient in moving bulk materials over varying distances, ranging from a few meters to several kilometers. The speed at which materials can be transported is a significant advantage, especially in large-scale industrial operations where time is a crucial factor. The ability to move materials quickly reduces operational downtime and enhances productivity.

Flexibility in Design and Layout: Pneumatic systems offer great flexibility in terms of installation. They can be designed to fit into complex layouts where traditional mechanical conveying systems may not be feasible. This is particularly advantageous in facilities with limited space or complex architectural designs. The pipes used in pneumatic systems can be routed around obstacles, and can ascend or descend between floors, making them highly adaptable to various industrial settings.

Low Maintenance and Operating Costs: Pneumatic conveyors have fewer moving parts compared to mechanical conveyors, which translates to lower maintenance requirements and costs. The simplicity of their design also means that they are less prone to mechanical failures. This reliability reduces the likelihood of unexpected downtime, contributing to more consistent operational efficiency.

Cleanliness and Safety: These systems are enclosed, which greatly minimizes the exposure of materials to the external environment. This is particularly important for handling hazardous, toxic, or sensitive materials. The enclosed nature of pneumatic conveying systems also reduces the risk of material spillage and dust emissions, contributing to a cleaner and safer work environment.

Versatility in Material Handling: Pneumatic conveyors are capable of handling a wide range of materials, from fine powders to larger particles. This versatility makes them suitable for various industries including food processing, pharmaceuticals, chemical manufacturing, and more. The ability to handle different types of materials without needing significant modifications is a key advantage.

At PAM we have extensive experience customizing pneumatic transport system designs to our customers needs and specifications. We have been developing solutions for pneumatic transport since 1935, and over the years we have continued to modernize and develop our approach. Thus, we can surely develop one that fits perfectly in your production line.   

Call us to find out which system best suits your needs.

Check a couple of cases here:

• Pneumatic conveying of fishmeal
• Mechanical and pneumatic conveying at a powerplant
• Handling of powders in chemical industry

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