MATERIALS HANDLING
Rotary vibrators supply energy best suited to moving fine, dry materials
TMOVING KEEP MATERIALS
Brad Pronschinske describes how engineered flow aids resolve bulk material handling issues
o achieve consistent flow on conveyors handling large volumes of bulk material such as coal, aggregate or biomass, transfer chutes and vessels must be designed to accommodate and facilitate the flow of the cargo they will be handling. But even if the operating conditions are expected to be ideal, many engineers include flow aid devices in new designs to ensure delivery of the specified results and deal with changes in bulk material properties. Designing a conveyor and chutework that would handle every material situation is virtually impossible. Materials with high moisture content can adhere to chute or vessel walls or even freeze during winter temperatures. Continuous operation can serve to compress the material, and physical properties often change due to natural variations in the source deposits. At times, the system can become completely blocked by just a small change in these parameters. To overcome these issues, a variety of devices collectively known as flow aids can be employed.
46
www.engineerlive.com
When employing flow aids, it’s critical that the chute and support components are sound and the flow aid be properly sized and mounted, because the operation of these devices can create potentially damaging stress on the structure. A properly designed and maintained chute will not be damaged by the addition of correctly sized and mounted flow aids.
Te best practice is to use the flow aid as
A piston vibrator should be installed on a steel channel mounted outside of the chute or vessel
WHAT ARE FLOW AIDS? As the term implies, flow aids are components or systems installed to promote the transport of materials through a chute or vessel. Because they will affect a conveyor’s loading, they can also impact spillage and dust. By designing active flow aids into a conveying system, the operation gains a level of control over the material that cannot be obtained with static approaches (such as low-friction liners) alone.
a preventative solution to be controlled by timers or sensors to prevent material buildup, rather than waiting until material builds up and restricts the flow. Using a flow aid device in a preventive mode saves energy, reduces noise and improves safety, since the flow aid runs only when needed while still reducing buildup and plugging.
AIR CANNONS One solution for managing material accumulation in chutes and vessels is the low-pressure air cannon, originally developed by Martin Engineering in 1974. Also known as an “air blaster,” it uses plant compressed
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
