Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors

by Don Mackrill

Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors (AMCs) – which is best?

Are you looking to see which conveyor is best, Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors?  Spiroflow has been at the forefront of the bulk material handling industry for more than 48  years, selling both types of conveyors. In this short article, we cover how each type of conveyor works, their similarities and differences, and how to best determine the best solution for a particular process.

Which is which?

Pneumatic (Vacuum) Conveyors

In a pneumatic or vacuum conveyor, the product is conveyed in a suspended stream of gas, usually air. When particulate materials are metered into an airstream, at an optimal solids-to-air ratio, the differential air pressure generated via a vacuum pump creates a high enough velocity to move the materials within the conveying tube.

Pneumatic conveying is a simple option to move material across challenging routes. The product is moved hygienically and is a good fit for several applications.

Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors

Aero Mechanical Conveyors

Aero Mechanical Conveyors are effectively ‘mechanical’ pneumatic conveyors offering many advantages of vacuum conveyors but at a reduced capital cost. It also has reduced running costs and operates without the hassle associated with the filtration equipment required to separate your product from the conveying air. The movement of the conveyor is so rapid it aerates the product. As a general rule, each pocket contains about 80% air and 20% material.

It is one of the most efficient methods of conveying materials. Its dust-free and clean handling properties make the conveyor a good fit for many applications across several industries.

Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors

What are the differences?

What makes each stand out when you compare Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors ? One may be a better solution for a particular process than the other. This next section examines the differences between both types.

AMC DART

The addition of a DART Automatic Rope Tensioning device can prevent needless maintenance issues, particularly during the initial breaking-in period of the conveyor or critical 24/7 operation when correct tensioning of the rope assembly is essential to ensure smooth operation.

Regular inspection and maintenance are not always an option if resources are stretched, or if the conveyor is in an inaccessible location, so the DART is a valuable option. Spiroflow offers the DART on AMCs and has seen examples of well-maintained and tensioned aero-mechanical conveyors running for 15 years before spare parts are required.

Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors

Is power consumption a priority?

AMCs can convey material at a rate from 400 Cubic Feet per hour to 1840 Cibic Feet per hour  depending on the diameter of the tube. These conveyors can achieve this by using a drive motor between 2-7.5 Hp through a gearbox. Pneumatic conveyors require a 20-40 Hp blower to reach comparable rates to an AMC.

Is noise a factor?

Pneumatic conveyors are much louder than AMCs, which operate below 85dBA. Pneumatic conveyors must be remotely installed or have mufflers installed, which adds to the cost of the system.

Does your process require multiple inlets or outlets?

Multiple outlets on vacuum conveyors require a separate receiver, its own pressurized air supply for filter cleaning as well as its own feed control valve and diverter valves. Additional piping is also needed to feed each individual usage point.

Each receiving point requires venting of the motive air as well as filters, valves, diverters, and additional piping to direct product to each use point for pressure systems.

Multiple inlets and outlets can easily be integrated with AMCs. When multiple outlets are used we recommend that the conveyor operates at half speed. This ensures that the material exits the conveyor properly. A tube valve at each outlet provides a smooth path for the ingredient to pass through.

What about venting?

One of the major advantages of an AMC is that it’s a balanced system. Ambient air is drawn into the conveyor along with the material and the material is discharged at the outlet of the conveyor. The displaced air is drawn back into the conveyor creating the balanced system. There are no special venting or filtering requirements because there is no pressurization at the discharge point.

Still have questions?

Do you still have questions about Pneumatic Vacuum Conveyors vs. Aero Mechanical Conveyors? It’s difficult to say which conveyor will truly work best for your process without an engineer knowing more about your operation. Not all processes are the same. At Spiroflow, we have a team of engineers in the United States and the United Kingdom that can help you. Feel free to contact us if you have any more questions.

Pneumatic Conveying