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PBEI | March 2017 15 Your pipeline to pneumatic conveying FLSmidth is a worldwide leader in pneumatic bulk conveying for process and material handling. For more than 80 years our pneumatic conveying systems have moved millions of tons of dry bulk solids in numerous applications across the globe. You'll benefit from proven equipment, system engineering expertise, and the design and installation of complete bulk material transfer systems – all supported by our global service network. www.flsmidth.com/pneumaticconveying excellence Inc. © REMBE | All rights reserved Gallbergweg 21 | 59929 Brilon, Germany | T +49 2961 7405-0 F +49 2961 50714 | info@rembe.de www.rembe.de Contact us for Europe Contact us for North America 3809 Beam Road Suite K Charlotte, NC 28217, USA T +1 704 716 7022 | F +1 704 716 7025 info@rembe.us | www.rembe.us GOT COMBUSTIBLE DUST? Call REMBE® – Your Explosion Protection Specialist WE ARE THE EXPERTS! Consulting. Engineering. Products. Service. In operation, an operator programs the controller to dis- charge material at a predetermined feedrate (or setpoint) mea- sured in weight per unit time (such as pounds per hour). The load cells continuously measure the material weight in the hopper, and the controller regulates the speed of the feed de- vice so the actual rate of weight loss matches the desired rate of weight loss. This allows the system to compensate for non- uniform material flow and variations in bulk density, provid- ing a high degree of feeding accuracy. How to optimize LIW feeder accuracy LIW feeding is most accurate when using a high-resolution, fast-response weighing system that's immune to vibrations and temperature fluctuations. You can further optimize LIW feeding accuracy several ways: by separating plant vibration noise from true weight loss, by controlling motor speed during feeder refill, and by compensating for process pressure fluctuations. 1. Separate plant vibration noise from true weight loss. A LIW feeder's operation depends on accurate measure- ment of the material weight in the hopper, so the feeder and weight-sensing device must be isolated from external forces and vibration. Position the feeder so that no external forces or friction can influence weighing. Isolate the feeding system by using flexible connections between the feeder and any other part of the system, such as the material or refill inlet and the feeder discharge. Install the feeder so that the weight-sensing device is shielded from vibration effects. Shock and vibration created by other process equipment in the plant can corrupt the load cells' weight measurement, destroying the basis for feedrate control. Ensure that the feeder has a stable mount- ing, using flexible connections and shock mounts, and elimi- nate strong air currents near the feeder. Figure 1 Loss-in-weight feeding system Refill hopper Refill device Feeder hopper Feed screw Variable-speed motor Load cells Controller