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Pneumatic conveying with vacuum and overpressure

Pneumatic conveying. The transfer of bulk materials or powders through a closed conveying pipeline. By means of flowing air. Transmitting a pulsation force on the materials to be conveyed.


How does pneumatic conveying work?

Pneumatic conveying is a proven and efficient method for the transport of bulk goods. Such as dusts, powders, granules and other fluidizable materials. Quickly and reliably. From one place within a production site to another.

We differentiate between two common techniques: Pneumatic suction conveying and pneumatic overpressure conveying. Depending on whether vacuum or overpressure is applied.

Pneumatic suction conveying

Pneumatic suction conveying is used for the transport of sensitive materials. To avoid any contact with the ambient air.
Therefore, pneumatic suction conveyors are the systems of choice in the food, pharmaceutical and chemical industry. As well as for transporting granules in plastics processing applications.
Moreover, vacuum conveyors can handle moist materials. For example, in the disposal of wet waste or the transport of bark mulch.

Pneumatic overpressure conveying

Pressure conveyor systems are similar to their vacuum counterparts. But work with overpressure.
The bulk materials are blown along pipelines from the source to their destination. With pneumatic overpressure conveying, high pressure differentials are possible. Therefore, even heavy products can be transported. For example, sand, gypsum and cement.

Busch vacuum technology in pneumatic conveying

No matter which materials are transported on your premises. We offer the perfect vacuum or overpressure solution to convey them safely and efficiently.

Learn more about pneumatic conveying with vacuum and overpressure

What is pneumatic conveying?

Pneumatic conveying is used to transport bulk goods efficiently and reliably from point A to point B within a production site. Goods such as powders, granules or other fluidizable materials are moved through a sealed conveying pipeline. This is made possible by differences in pressure and gas flow. The latter are created either by using vacuum in the case of pneumatic suction conveying, or by applying overpressure in the case of pneumatic overpressure conveying. In cases of suction, materials are drawn through the pipeline and avoid any contact with the ambient air. When overpressure is in use, the bulk materials are blown along the pipelines from the source to their destination.

How does wet-waste conveying work?

The waste material is transported by a vacuum conveyor to a receiving vessel. Once in the container, it is shredded, homogenized, and stored for later collection. The collection is usually made by a road tanker, with the transfer from the receiver to the tanker also carried out by a vacuum conveyor.
Wet-waste conveying is split into lean and dense phases. The lean phase is characterized by high air flow and high velocity of the bulks. In the dense phase, the air flow and the bulk velocity is low and the differential pressure high.

How do pneumatic suction conveying systems work?

Pneumatic suction conveying systems administer a vacuum at the receiving end of the transport pipeline. The material is thus pulled through the enclosed piping. Suction conveying systems are mainly used for lean phase conveying. Such units are mostly installed for conveying applications with different intakes and one handover.

How do pneumatic overpressure conveying systems work?

Pneumatic pressure conveying systems work with overpressure. The bulk materials are blown along pipelines, from the source to their destination. These systems allow for high pressure differentials making it possible to even transport heavy products.

Where is vacuum or overpressure used in pneumatic conveying?

Vacuum is used in pneumatic suction conveying to pull the bulk goods through a pipeline. In pneumatic overpressure conveying, overpressure is applied to push the material from the source to their destination.

What are the advantages of pneumatic conveying over mechanical conveying?

Pneumatic conveying units are flexible in terms of installation. They require less space for piping than mechanical conveying systems. Moreover, their operation is dust-free and avoids cross-contamination. Another advantage is the reduced maintenance for rotating parts within the system.

What are the best vacuum pumps/compressors for pneumatic conveying?

The most suitable products for pneumatic suction and overpressure conveying are rotary lobe blowers, side channel blowers and dry claw vacuum pumps and compressors. Rotary vane vacuum pumps can be used for pneumatic suction conveying as well. In some specific applications, liquid ring vacuum pumps might also be an option.

What are the best vacuum pumps from Busch for the pneumatic conveying process?

MINK vacuum pumps represent the most economical, reliable, and clean solution available for pneumatic suction conveying of sensitive materials. The extracted air is compressed without the necessity of operating fluids. Their operation is therefore nearly maintenance-free. In addition to MINK claw vacuum pumps, proven R5 rotary vane vacuum pumps are used whenever higher vacuum levels are required. If materials are to be transported in relatively large volume, the first choice would be SAMOS side channel blowers or TYR rotary lobe blowers.
All of the above vacuum pump types run highly efficient in their respective operating range.

What are some examples for the use of Busch vacuum technology in pneumatic conveying applications?

Busch vacuum pumps are used globally for suction conveying of food, granulates and plastic pellets. Our solutions also play a role in overpressure conveying of bulk goods and conveying of wet-waste for disposal or reprocessing. Central vacuum systems from Busch are specifically designed for large or complex conveyors. They are fully commissioned at the customer’s installation site including separation units and control systems as required.

What are the key points to consider when buying a pneumatic conveying system?

When thinking about purchasing a pneumatic conveying system, the required pumping speeds and vacuum levels are vital considerations. Transportation speed, material characteristics, conveyor line length and pipe diameters also play an important role.
However, there is no one-size-fits-all pneumatic conveying solution. For purposes of designing the best solution for your needs, more general factors can also be taken into consideration:

Peace of mind
The best vacuum system is the one you never have to worry about. It should deliver the required performance. And run seamlessly and reliably. This is achieved by a combination of the right technology in a suitable skid integration. And the required protection and safety sensors. The correct operating procedures, including warm-up and shut-down cycles, are also key factors for trouble-free operation.

A pneumatic conveying, vacuum conveying or plastic conveying system should never pose a danger to workers. This is especially important whenever explosive, flammable, and toxic compounds are being handled. In this case, the vacuum system needs to comply with local explosion regulations such as ATEX, IECEX, Ex-Proof or KOSHA. The right level of leak-tightness is also crucial to prevent any seepage of toxic compounds. In this case, specific options such as double mechanical seals and barrier gases are recommended.

Cost of ownership
Focusing only on initial investment costs is usually not the best way to optimize the total cost of ownership of a pneumatic conveying, vacuum conveying, or plastic conveying system. Several other parameters must be considered: Mainly to choose the right technology and to adapt the system design. Fixing the right operating conditions allows to save costs for maintenance and reduce product waste. Moreover, it is important to take a holistic look at the vacuum system. Pipes that are too small, for instance, can greatly impair the performance of the system.

Energy efficiency
The energy consumption of a pneumatic conveying, vacuum conveying or plastic conveying system is a key selection factor. Depending on the operating pressure, different technologies can be considered. Additionally, regulation of vacuum demand is key. Nowadays, most systems can be operated with a variable speed drive to reduce power consumption when vacuum demand is low.

Extended lifetime
To extend the lifetime of a vacuum system several factors should be considered. For example, the use of the right technology and the right pump configuration. Another consideration is the proper use of the system. In most cases, warm-up, and shutdown cycles, including Clean-in-Place (CIP), are required to maintain performance at factory standards.

Money savings by system upgrade
Your process, including vacuum demand, may have changed. This leads to the questions: Is it still adapted to your needs? Is it still operating as energy-efficiently as possible? When it is time to upgrade or replace a vacuum system, it is worth looking at the entire installation. We will support you in identifying any potential for optimization.

Pneumatic conveying in the plastics industry

Jedi Kunststofftechnik GmbH is a leading manufacturer of soft PVC rolls, sheets, and web material. The material is fed from the delivered big bags to the extruders via a pneumatic suction conveying system.

Vacuum generation in the conveying system has been redesigned and implemented with the help of Busch specialists. Since the beginning of 2018, Jedi Kunststofftechnik has had frequency-controlled MINK claw vacuum pumps in operation. They are much more energy-efficient than the side channel blowers previously used.

This has enabled the energy consumption for vacuum generation to be reduced by up to 70 percent. In addition, downtime and repair costs have been cut, and the noise level is now considerably lower.

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Pneumatic suction conveying of plastic pellets

Pneumatic suction conveyors are frequently used in the plastics industry. To feed plastic granules and additives into processing equipment. Such as extruders or injection molding machines.

These conveyor systems have several advantages: They are clean, efficient and nearly maintenance-free. And allow for an outstandingly smooth transport. Avoiding excessive abrasion or breakup of the raw material. Moreover, pneumatic suction conveyors are relatively easy to reconfigure. Which reduces the cost of production line alterations.

Our solutions

Pneumatic conveying in wet-waste treatment

LSG Sky Chefs FRA ZD GmbH prepares about 100,000 meals daily for Lufthansa and its partner airlines at Frankfurt Airport. The extraction of residual waste from 26 tons of refuse a day is carried out by a centralized vacuum system.

The original vacuum system was equipped with three liquid ring vacuum pumps. They will all be replaced by TYR rotary lobe blowers from Busch. The new blowers are considerably more energy-efficient and require significantly less maintenance. When the conversion is complete, the resulting savings will be an estimated 70,000 Euro per year.

Pneumatic conveying in other industries

Pneumatic suction conveying of foodstuffs

Pneumatic suction conveying offers an efficient and contaminant-free way of transporting foodstuffs. Either in free-flowing granular or powder form. The products are fluidized through the air flow generated by the vacuum pump. And move freely along pipelines to their destination.

The vacuum in the conveyor ensures that the transported goods have only minimal contact with atmospheric oxygen. Thus, preserving the product aroma. If required, the transport medium can be an inert gas such as CO2. Allowing to further preserve product quality and freshness.

Our solutions

Pneumatic suction conveying in the chemical and pharmaceutical industry

Pneumatic conveying is commonly used as a gentle transport method in the chemical and pharmaceutical market. To move raw materials, solvents, intermediates and finished powders. With the help of vacuum, they are safely conveyed from one place to another. Without any risk of toxic or flammable materials escaping into the environment during transport.

If materials with a high risk of explosion need to be processed, ATEX-certified vacuum pumps further increase safety. Moreover, the products are not degraded during transport. Because being conveyed under vacuum, they only have minimal contact with atmospheric oxygen.

Our solutions

Wet-waste conveying

Pneumatic conveying is commonly used in wet waste systems. Wherever wet refuse and leftovers need to be disposed or reprocessed: In hotels, hospitals and canteens. But also in slaughterhouses, fish processing companies and cruise liners.

A vacuum conveyor transports the waste material to a receiving container. Where it is shredded, homogenized and stored for later collection. The system is hygienic, efficient and environmentally friendly. Allowing waste to be reprocessed to manufacture biogas, animal feed or fertilizer.

Our solutions


Pneumatic Conveying in practice

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  • Up to 70 Percent Energy Savings Thanks to Modern Vacuum Technology for Material Feed

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