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Pneumatic conveying is a system used to move powdered or granular products through an air stream, carrying the material from a pickup point to the desired destination. As a closed, versatile, and highly customizable system, it is widely used in industries that require cleanliness, operational safety, and layout flexibility.
In diluted phase it can be divided into two cases, they are:
In dilute phase positive pressure pneumatic conveying, the product is carried by an air stream generated by a blower, usually installed at the beginning of the line.
In this type of system, air is injected into the pipeline at a pressure above atmospheric pressure, pushing the material to the discharge point. Since conveying takes place in dilute phase, the particles remain mostly suspended in the air flow and are transported at relatively high velocities, generally in the range of 16 to 30 m/s, depending on the product, particle size, density, and line layout.
Positive pressure is one of the most widely used solutions in industrial systems due to its versatility and the wider pressure range available.
A positive pressure system is usually recommended when the process requires material to be transported from one or a few feeding points to one or multiple destinations.
Because it operates at higher velocities, the system must be carefully evaluated when the product is fragile, brittle, or sensitive to degradation, since impacts in bends, valves, and discharge points can cause changes in particle size or loss of material quality.
It is also important to consider that the air generated by the blower may increase in temperature during compression. For hygroscopic or heat-sensitive products, such as sugar, flour, and some food powders, additional resources may be required, such as cooling and dehumidification to control the temperature of the conveying air.
In general, due to its wider available pressure range, positive pressure pneumatic conveying is an excellent option for low, medium, and high capacities, long distances, and systems that require good distribution flexibility.
Example of positive pressure pneumatic conveying |
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In dilute phase vacuum pneumatic conveying, the product is carried through the pipeline by means of pressure below atmospheric pressure. Instead of “pushing” the material, as occurs in positive pressure systems, the system creates a suction condition, pulling the product to the receiving point.
In this type of system, the vacuum-generating equipment is usually located at the end of the line, after the filter. Air enters the pickup point at ambient temperature at the beginning of the line, carries the product through the pipeline to the final destination, where the material is separated from the air by a pulse-jet bag filter, and the air continues toward exhaust through the blower.
Transport speeds can be similar to those used in positive pressure systems, however the available pressure range is usually smaller and, because it is a system that operates at absolute pressures below atmospheric pressure, it requires larger filtration systems due to the behavior of the air along the line.
Vacuum conveying systems, also called negative pressure systems, are mainly, but not exclusively, used to transport materials from multiple sources to a single destination.
A vacuum system is a highly versatile solution and, depending on its design, can be applied across different operating ranges. In low-pressure lines, suction can be generated by exhaust fans; in applications that require greater capacity or greater available pressure drop, blowers or vacuum pumps may be used.
This option becomes especially suitable when the material is not hygroscopic or when it may be affected by contact with heated air, since the vacuum system does not directly inject hot air into the conveying line.
On the other hand, since the available vacuum pressure is more limited, the project must carefully consider the line distance, number of bends, filter pressure drop, required capacity, and product characteristics.
In general, vacuum pneumatic conveying is a highly suitable solution for low to medium capacities and short to medium distances.
Example of vacuum pneumatic conveying |
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Criterion | Positive pressura | Vacuum |
|---|---|---|
Operating principle | Pushes the product through the line | Pulls the product through the line |
Typical blower position | Beginning of the line | End of the line |
Typical capacity | Medium to high | Low to medium |
Typical distance | Medium to long | Short to medium |
Risk of dusk leakage | Higher, if there are sealing and/or sizing failures | Lower, as it operates under negative pressure |
Air temperature | May increase after the blower | Generally has less thermal impact at pickup |
Main concern | Abrasion, degradation and air heating | Pressure drop limit and filter sizing |
Conveying rate | Can operate wigh higher capacities and higher conveying ratios | Usually requires more moderate rates, especially in long lines or lines with higher pressure drop |
In general, pneumatic transport is a succinct system, the main equipment that makes it up is:
Various other equipment can be used in the system, but does not necessarily have a direct relationship with its operation, such as silos, bag-receiving hoppers, micro-ingredient dosers, insect destroyers, among others.
In general, pneumatic conveying is a relatively simple system. The main equipment that makes it up includes:
Several other pieces of equipment may be used in the system, although they are not necessarily directly related to its operation, such as silos, bag dump receiving hoppers, micro-ingredient feeders, infestation destroyers, among others.
Rotary valve
We manufacture rotary valves with a wide variety of specifications, with model lines for heavy-duty, reinforced, hygienic, and easy-cleaning operation. They are developed with minimal internal clearances and precision machining, contributing to system sealing and efficiency. |  |
Flow diverter/converter valve
It can be used as a diverter, when one inlet directs the flow to two outlets, or as a converter, when two inlets converge into a single outlet. In both cases, one channel remains open while the other stays closed, ensuring control and safety in product direction. |  |
Pulse-jet microfilter
In addition to its filtration function, it also acts as the receiving and depressurization point of the line, allowing the product to be discharged in a controlled manner. It can be designed in different configurations. |  |
One of the main advantages of this type of process is its high installation flexibility. By using pipes, bends, and modular components, the system can overcome long, elevated, or winding routes while occupying less space, making it a practical alternative in industrial layouts where mechanical conveyors would be more complex to install.
In addition, it can handle a wide range of capacities and distances, according to project sizing. We already have systems applied in lines over 300 meters long and with capacities of up to 40 t/h, demonstrating its versatility for different industrial processes.
As a closed system, when properly sized, it helps reduce external contamination, improves organization in the production area, and minimizes points of material accumulation. In this way, pneumatic conveying becomes an efficient, clean, and competitive solution compared with other alternatives for moving bulk products.
Some products already transported
Check out some products already transported for reference. |  |
In general, pneumatic conveying is a practical and efficient system, but it requires attention to important sizing details, such as minimum conveying velocity, product characteristics, line layout, and correct equipment specification. A small overlooked point can lead to failures such as leaks, pressure loss, low capacity, or material buildup in the pipeline. For this reason, working with a partner with know-how and experience in the subject makes all the difference.
Would you like to learn more or find the best solution for your process? Contact our specialists and let us design while you produce.
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