Pneumatic Transfer of Dusty Powders for Compounding & Extrusion Processes

10 Things You Need to Know When Designing a Vacuum Conveying System for Your Process

Application: Utilizing pneumatic conveying for “receipt-to-process transfer” of dusty powders and other granular bulk materials

Background: As all processes vary, so does the technology used to move bulk materials from source to destination. Typically in pneumatic conveying applications there are two types of technologies, Dilute Phase Vacuum Conveying and Dense Phase Vacuum Conveying. In Dilute Phase Vacuum Conveying, the bulk materials are entrained in the air stream. Up to 25,000 lbs per hour (11,000 kg/hr) of powders / bulk materials can be moved, for distances less than 300 feet (90m). Typically the line sizes for these applications are up to 6" (150 mm).  In Dense Phase Vacuum Conveying applications, the conveying velocity is lower, ideal for moving fragile bulk materials, for minimal product degradation. Typically these applications are higher volume, up to 29" HG (982 Mbar). Dense Phase Vacuum Conveying is also used to convey powders to tanks under level of fluid. Typically these applications are higher volume, up to 29" HG (982 Mbar). Dense Phase Vacuum Conveying is also used to convey powders to tanks under level of fluid.

Technology: Dilute Phase Positive vs. Dense Phase Positive
Pneumatic Conveying technology is further broken down to Dilute Phase Positive Pressure Conveying and Dense Phase Positive Pressure Conveying. Typically Dilute Phase Positive Pressure Conveying is used for applications requiring higher rates and longer distances. This technology is also best suited for applications requiring conveying to multiple destinations, from one pick up point, or many pick up points. In this application, leakage of bulk materials is outward, and not recommended for combustible dusts, as noted by the NFPA. Dilute Phase Positive Pressure Conveying is typically lower pressure, below 15 PSI (1 bar).  Dense Phase Positive Pressure Conveying is also known as "brute force" conveying. In this application, a lot of compressed air is used to move the bulk materials over longer conveying distances. This is the preferred technique for friable bulk materials, with pressures above 15 PSI (1 bar)

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"10 Things to Know when Designing a Vacuum Conveying System for Dusty Powders"