Pneumatic conveying systems transfer powders from the source to the processing line by using either negative pressure or a vacuum. The advantage of such a process is dust control. Given its combustibility, dust is a safety hazard.
It eliminates dust caused by hand scooping by transferring the powder in an enclosed system. In order to properly design a vacuum conveyor system there are a few things to consider.
1. Your Bulk Density
You need to know the density of the powder being conveyed. This will enable you to calculate the size of the vacuum receiver and the conveying velocity. Materials with higher bulks require faster transport velocity.
2. Conveying Distance
You’ll need to know your distances both horizontally and vertically. You’ll want to reduce the number of 90-degree elbows also, as powders do not flow like liquids.
3. Conveying Rate
How many kilos per hour will be conveyed? Also, will the process be batch or continuous? It is essential to know in order to size the system correctly.
4. Bulk Material Characteristics
Are they floodable, fine or cohesive and what is their shape and size? When you know these, you’ll be able to understand better how the powder will flow.
5. How Will the Materials Be Received?
It is important to know how the materials will be received and entered into the process. Powders can be received in anything from paper bags to railcars or upstream process equipment.
6. Upstream Process
You need to know if the powder is coming from a volumetric feeder, reactor, mixer, extruder hopper or loss-in-weight feeder, as these all influence the conveying process.
7. Headroom Requirements
This is important when designing equipment for a plant that was originally designed for manual operation. Even small conveying systems require 30 inches of head room when maintenance requirements are taken into account.
8. Batch or Continuous Process?
A vacuum conveying specialist such as http://www.aptech.uk.com/pneumatic-conveying-systems/vacuum-conveying will need to know if it is a batch or continuous process so they know how to enter the material into the system.
9. What Are the Atmospheric Conditions?
Know your atmospheric conditions, especially altitude. The higher the altitude, the more air will be required to convey the powder.
10. Construction Materials?
Most construction materials are metallic, including stainless steel, aluminium and coated carbon steel, but some materials go better with different surfaces. Food processing, for example, goes better with stainless steel.