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18 / March 2020 powderbulk.com PNEUMATIC POINTS TO PONDER Jack D. Hilbert, PE, and Étienne Brochu, guest co-author, Hatch Pneumatic conveying system pipeline routing W e often update and re-issue a topic from past "Points to ponder…" col- umns based on reader, equipment end-user, and sometimes client interest and activity levels. Some col- leagues and I recently visited several bulk solids processing installations, and the topic of conveying line rout- ing and orientation came up and was discussed on numerous occa- sions. The intent of this column is to provide you with typical guidelines that could help when the time comes to de ne a pneumatic conveying system's routing. One of the advantages of pneu- matic conveyors is that they offer good routing exibility compared to other types of material trans- port systems. Pneumatic convey- ing systems have the advantage of being able to accommodate various routing geometries since the mate- rial is conveyed through a pipeline versus a mechanical conveyor open to ambient conditions. However, people who aren't familiar with pneumatic conveyors will generally think that, like standard pipeline, these systems have almost no lim- itations with regard to routing. The truth is that pneumatic conveyors do have their own limitations. Before describing pneumatic conveying line geometry good practices, let's de ne what a "basic" pneumatic conveying system con- sists of. A basic pneumatic conveyor is made up of various components assembled together. These include a gas mover, a product line charger, a conveying pipeline, and a product receiver. Of these, the pipeline is the component that links all other equipment together to form one sin- gle system. For a given material and mass- ow stream, pipeline geome- try is a parameter that can in uence a system's ef ciency. For that reason, understanding good conveying line geometry practices is important. Material acceleration zone The conveying line's most import- ant section is at the material feed- point. Obviously, if the material can't get moving downstream and entrained into the conveying gas stream, the system pressure will rise, and conveying capacity will be limited — possibly to the point of a plugged line. Pneumatic conveying modes There are three modes of pneumatic conveying: dilute-phase ow, two- phase ow, and permeable dense- phase ow. The conveying mode to be used depends primarily on the material's physical and chemical characteristics. What follows are pneumatic conveying line geometry guidelines for each conveying mode. PBE Patented Nozzle Based Cleaning System Since 1981, we have been building your Dust Collectors right here in the USA. Bag Life Guarantee Performance & Efficiency Guarantee Let us help you 'Discover the Difference' (708) 597-7090 www.scientificdustcollectors.com