Dry solids handling problems choke plant capacity and reduce operating efficiency. Conveyance, storage and discharge are just a few of the areas that are prone to problems. Proven solutions and tips for solving many solids handling problems can be gleaned from visits to consultants' Web sites, discussion forums and equipment manufacturers' Web sites.
Jenike & Johanson's well-known bulk solids consultancy has a Web site that opens with a list of problems that can often be solved through on-site troubleshooting. You can watch two QuickTime videos, Flooding and Segregation, through links included in the list.
The company's educational offerings include courses, newsletters, case studies and papers. Courses, workshops and seminars cover flow of solids, pneumatic conveying and advanced solids handling. You can find course content details, availability and registration information through individual links on the course page. The company's "Flow of Solids" newsletters can be downloaded in Adobe Portable Document Format (PDF).
Each newsletter includes articles, questions and answers. Topic titles include: "New American Society for Testing and Materials (ASTM) Standards for Segregation Testing," "Handling Bulk Solids in a Fluidized Condition," "Is a Polished Hopper Wall Surface Really Needed?" and "Silo Failures: Why Do They Happen?" More than 40 case studies and papers are available.
Forums on the Internet have made it possible to ask and answer specific questions about virtually any topic. Most forum discussions can be viewed with your browser. Registration and a password are often required to post questions and comments. However, registration is usually offered free of charge. You can search forums for keywords or phrases and you can locate questions that have been discussed previously.
The bulk-online forum is an example of a group of active solids handling forums. "Ask Lyn" is a platform for posing queries from users who are experiencing problems in solids storage and handling or looking for advice about a project. An entry posted by bulk-online.com's president Dr.-Ing. Reinhard H. Wohlbier, "Answers to 10 Common Questions about Storage Hoppers," provides a link that discusses hopper design, flow characteristics and the relative merits of different hopper shapes.
The question, "How can I work out the holding volume of a hopper, taking account of surface repose conditions of the material in various cross sectional shapes?" elicited a link to Ajax Equipment where Lyn Bates is managing director. A pull-down menu links to fill-in forms for calculating the volume of a chisel or conical hopper. There is also a pull-down menu link to a bulk density database for hundreds of common materials.
The Bulk Materials Handling & Processing Forum provides discussion of solids handling problems posted by users. Topics range from bins and bucket elevators to pneumatic conveying and vibrating feeders. An "Ask Joe!" column by Joe Marinelli of Solids Handling Technologies provides additional answers and insight in the Powder and Bulk Dot Com Help Forums. Interaction in the forums is positive and focused. A "Dust Collection" user is seeking better technology than the present bag houses he uses that are costly due to power consumption and frequent bag replacements. More than 10 replies focus on bag discharge techniques, sizing, design and controls.
For example, one reply from Tim Agarwal, Pneumatic Conveying Consultants, states: "You should check your can velocity (Superficial Gas Velocity outside the bags) to improve dust release from the bags. If this velocity exceeds the dust's terminal velocity, dust particles will collect in the upper part of the bag house against the tube sheet, resulting in very high dust loading on the bags. Also, look into top-loading bags instead of bottom loading to reduce time needed for bag replacement."
