What Is Pneumatic Conveying and How Do These Systems Work?

Pneumatic conveying is an efficient means of handling and transferring various types of bulk granular and powdered products, with minimal loss and at a lower cost than other systems.

You can use pneumatic conveying for many types of products across a wide range of industries, including chemicals, foods and beverages, and much more.

What Is Pneumatic Conveying?

Pneumatic conveying systems use a series of pipelines that move products by pumping air.

pneumatic conveying

These products typically consist of powders or granules. These systems function by moving materials through enclosed, airtight pipelines through a combination of airflow or another type of gas and pressure.

Operators can control positive or negative pressure of airflow to smoothly transfer products without worrying about damage or loss.

What Are the Advantages of Pneumatic Conveying?

There are several advantages of pneumatic conveying, including:

  • Pneumatic conveyors can run long distances either horizontally or vertically.
  • These systems are easier to locate because they require less floor space.
  • The compact design of pipe transfer lines makes it easy to route pneumatic conveying systems around equipment currently in use, making it suitable for use in more applications than mechanical systems.
  • Enclosed nature blocks dust from entering into the surrounding area while ensuring that contaminants don’t enter the pipeline.
  • Operators can maintain a consistently controlled atmosphere.
  • Multiple pick up and discharge points are available.
  • Fewer moving parts means that they’re easier to maintain compared to mechanical systems.
advantages to pneumatic conveying

What Are the Disadvantages of Pneumatic Conveying?

There are some downsides to using pneumatic conveying systems, which could include:

  • Inability to use with higher product volumes without some challenges, as most pipelines measure from around 3 to 12 inches.
  • Blowers and fans can produce a lot of noise, but this can be mitigated with sound enclosures.
  • Product damage and line plugging can occur with wet or fragile products, seeing as wet products can plug pipelines while fragile products may not be able to withstand the high-velocity airflow and sharp turns.
  • The use of dust collectors with open-circuit systems can result in discharge of dust into the atmosphere, which may require a permit.
  • The blower size is often limited, which subsequently limits scalability if you want to install larger systems.

Is Hydraulic Better Than Pneumatic Conveying?

There are advantages and disadvantages to using hydraulic and pneumatic conveying.

While hydraulic systems can more efficiently transfer heavier loads with greater force compared to pneumatic systems, you can benefit from cleaner technology when using pneumatic systems.

Pneumatic conveying systems are airtight and don’t come with the risk of leaking that you get from hydraulics. Pneumatic systems are also easier to maintain than hydraulic systems because of the lack of moving parts.

Ultimately, there are plenty of reasons to choose pneumatic conveying systems over hydraulics, depending on the application and your facility’s specific needs.

What Are the Different Types of Conveyors?

There are two main types of pneumatic conveying systems to choose from: lean phase and dense phase. Each is used for different applications and includes different functions.

Lean Phase

The most commonly used pneumatic conveying system is a lean phase system used for granules and powders. There are two subcategories extending from lean phase systems:

Dilute Phase

Dilute phase conveying systems use gas velocities of greater than 17-18 m/s with lower vacuum or conveying pressure that falls below 0.1 barg. In dilute phase conveying systems, material particles are wholly suspended within the air or gas stream while the solids loading ratio is significantly lower.

This type of system is ideal for conveying non-abrasive materials with low bulk density. Most systems would use side channel blowers or fans to move the product along the pipelines.

Common applications for dilute phase systems include:

  • Non-abrasives like flour
  • Products that are difficult to break
  • Light bulk-density materials

Medium Phase

In medium phase pneumatic conveying systems, the gas or air velocity typically exceeds 17-18 m/s with a vacuum or pressure of as much as 0.35 barg.

Particles traveling through the pipelines remain suspended throughout, with a low concentration or solids loading ratio. Exhausters and roots blowers are often used to push air or other gas through the system.

Dense Phase

If you want to move sensitive or fragile products, dense phase conveying systems are ideal.

You can use these systems to handle and transfer products at lower velocities, which helps prevent impact damage to the product. Dense phase systems use pulses of air to push the product through, followed by another pulse of both the air and product.

Unlike lean phase systems, dense phase systems require more precise calculations for designs and proper timing. The overall density, size of the particles, and the run or length will help determine the ratio of air to product when using these systems.

Some common applications for dense phase systems include:

  • Abrasives including sugar
  • Materials with heavy bulk densities
  • Blended products
  • Certain friable materials like carbon black prills
  • Plastic pellets and other products that don’t require continuous delivery
dense phase conveying

Based on the specifications of your application and the type of product you need to handle and transfer, you can find the right pneumatic conveying system to get the job done.

How Does a Pneumatic Conveying System Work?

Pneumatic conveying systems work by flowing air through pipelines, transmitting a propulsion force that moves bulk products through the system from one end to another. Pneumatic conveying demands a pressure difference between the starting and endpoints of the system, which is achieved through the use of compressors, fans, or blowers.

how does a pneumatic conveying system work

The pressure differential will depend on a number of factors, including the length and layout of the system itself along with the volume and concentration of the product.

The specific method of conveying will differ between the different types of conveying systems, whether it’s a lean or dense phase system.

No matter how complex your dry bulk application is, or what dry bulk material you convey, Pneu-Con can pinpoint and solve your most challenging issues, and develop targeted engineered solutions that work. Contact us today to get started on your project!

BV Sarma

Director of Technical Services
BV Sarma is the Director of Technical Services at Pneumatic Conveying and has over 25 years of experience in the industry. BV's expertise lies within the product lifecycle and engineering custom solutions that meet organizational goals from vision to launch.