Dry bulk pneumatic conveying systems are used to move bulk materials that don’t contain any water, such as talcum powder or plastic pellets, through an enclosed pipeline system.
This system is commonly used in the processing and manufacturing various types of goods, from breakfast cereals to pet kibble. In this quick guide, you’ll find information on how dry bulk pneumatic conveying systems work, the components they use, and the types of materials they convey.
What is Dry Bulk Pneumatic Conveying?
Dry bulk materials are usually unprocessed raw materials that are shipped in large containers to factories or processing sites, where they’re moved to wherever they’re needed through specifically designed systems. Coal, ores, cement powder, and even electronic components are some examples of bulk materials. Conveying these types of materials within processing sites or manufacturing plants requires specialized systems, like pneumatic conveying systems.
Dry bulk pneumatic conveying involves the use of gas (air or nitrogen) to convey granular, powdery, or lumpy materials that don’t contain water. In these systems, gas pressure differential and gas flow are combined to move the materials within the processing area or factory premises.
What is a Dry Bulk Pneumatic Conveying System?
Moving bulk materials, especially light powdery ones like coffee creamers, is very challenging. Trying to move them using conveyor belts or in batches using large containers isn’t practical as it can become very messy very quickly. This is because, given the composition of the materials, particles can easily be spilled and blown around.
Therefore, powdery bulk materials need to be contained inside pipelines, where air or gas is used as the carrying medium instead of multiple moving parts. This is exactly what dry bulk pneumatic conveying systems do.
How Do Dry Bulk Handling Systems Work?
Dry bulk handling has several stages, including transporting the material from the source, delivering it to the manufacturing plant, and conveying it through the dry bulk handling system. From there, the bulk materials may either be stored temporarily or directly processed.
Dry bulk pneumatic conveying systems work mainly through the action of gas flow and pressure differential. Put simply, materials are conveyed through the pipelines by the flowing gas, which is made possible by the various components inside the system.
A dry bulk handling system is typically a customized conveying system designed for specific dry bulk materials. Although the design, size, and power may vary, there are four main categories of components in a pneumatic conveying system:
- Prime movers: These provide the thrust or power that moves the gas inside the pipelines. They include compressors, fans, and vacuum pumps. The pressure and speed of the gas must be carefully calibrated based on the type of bulk material.
- Feeders: The bulk material must be carefully fed into the system to prevent spillage and mess. This is what feeders facilitate, and they include components like chutes, hoppers, valves, and blow vessels.
- Conveying pipeline: Pipes, elbows, and couplings are the parts that contain the gas and the bulk material being conveyed. They must be the right size and angle so that they’re suitable for the materials being conveyed.
- Disengagement components: These include cyclone separators or fabric filters. The main purpose of these parts is to separate the solid particulates from the gas.
What Types of Materials Do Dry Bulk Systems Convey?
Dry bulk handling is not a one-size-fits-all solution; the system has to be specifically designed for the bulk materials it’s conveying. For example, a dense phase or dilute phase conveying system will each handle different products: while dense phase conveying systems are designed for tightly packed materials, like dog kibble or plastic pellets, dilute phase conveying is used for lighter materials, like talcum powder.
Several considerations have to be factored into the design of a dry bulk handling system, such as:
- Particle size and shape
- Friability
- Moisture content
- Abrasiveness
- Toxicity
- Explosive properties
In order to work in a dry bulk pneumatic conveying system, the materials must either have zero water content or a water content that’s very negligible. Some examples of dry bulk materials include:
- Plastic pellets
- Minerals
- Coal
- Woodchips
- Sand
- Sugar
- Flour
- Rice grains
- Salt
Handling these different materials requires special designs and processes. However, some bulk material handling systems may be able to handle similar materials. For example, various types of cereals can be handled by just one system.
