3 Reasons Why Particle Velocity is the Most Accurate Measure of Powder Feed Rate and Dilute Phase Conveying Velocity

Posted by Justin Dechene on Jun 16, 2017 11:30:00 AM

Stop guessing & start controlling

particle velocity measurement reduces the process uncertainty of measuring just air velocity in pneumatic conveying

Controlling bulk material feed rates is essential for a wide range of industrial processes. Traditionally though process engineers have had to calculate, or frankly, guess. Industry has lacked an effective instrumentation for monitoring actual particle velocity often using gas/air velocity as a very approximate proxy.. Auburn Systems has solved this with an adaption of their patented triboelectric technology for use in bulk flow monitoring.

Auburn Systems’ TRIBO.series particle velocity monitor provides a greatly improved monitoring option for bulk powder feed rate and dilute phase conveying. Let’s consider why particle velocity monitoring proves to be a superior option compared to older methods. 

#1 - Addresses Common Mechanical Drawbacks

Nonintrusive triboelectric probes perform better than mechanical feed rate measuring devices. The non-contact nature of testing makes it suitable for food, pet food, pharmaceutical and even high grade resin applications which are particularly sensitive to contamination. Removing paddles and other mechanical devices eliminates wear/maintenance points and also eliminates a flow disruption which can contribute to blockages. These advantages mean it can be broadly adopted, and it's fundamental accuracy makes the data valuable for accurate process control rather than as a relative indicator.

#2 Monitor Particle Velocity Rather Than Air or Gas Velocity

In dilute phase conveying, the conveyed material needs to stay at or above the minimum conveying velocity to remain entrained in the airstream throughout the system. Pickup speed depends on a number of product attributes and air speed has to be adequate. Yet process engineers fight the urge to simply increase speed because of common complications which include wear and maintenance to the conveying system, increased heat generation, greater energy consumption for air generation, and various product damage issues. Heat sensitive products can be damaged, melt or smear as speed increases while many others like cereals experience far higher loss rates due to damage.

That means the right answer is a specific range of speeds, not simply a min to pick-up and avoid blockages vs. a max to minimize damage.

While various air speed monitoring devices exist, TRIBO.series particle velocity monitor directly measures the velocity of the particles in the airstream. Since air speed does not necessarily equate with particle velocity, especially on materials with larger particles or mixed sized particles, directly measuring the particle velocity provides increased accuracy and helps prevent product dropout and substantially reduce breakage/damage.

Blockages carry a huge related set of costs in terms of product quality and unplanned downtime. Reducing these through more accurate monitoring means that companies stand to realize substantial additional savings - often up to 1-4 hours of very valuable production time per blockage induced disruption.

nonintrusive instrumentation measures particle velocity without possibility of product contamination

#3 Signaling, Alerts, Data Storage & Analytics

The TRIBO.series instrumentation offer multiple outputs that operators can use to monitor their feed operations. Rather than just having a mechanical device that transmits analog data, TRIBO units can output their signal in a number of ways: straight to nearby display or to the control room via 4-20 mA signal, RS-485 or Ethernet using MODBUS or Ethernet/IP back to a PLC or other data management system.

The system can be configured with various alert thresholds which allow for consecutive warnings. For instance, as particle velocity starts to drop to levels indicating a developing blockage an alert can be issued followed by an alarm to shut down blending processes in case flow falls below minimum levels.

Additionally data can be accumulated for analysis. For example, companies could use the data to explore what conditions (raw material, climate, time of day, etc.) may correlate with disruptions in flow and possible process variables which can be eliminated?

Conclusion

By having more accurate measurements of the material feed rates plants can maintain greater control over their processes.

Having trouble with controlling feed rates in your dilute phase conveying system? Let Auburn Systems help you find a better monitoring solution to achieve your performance goals. Contact us today!

Have an application to discuss? Give us a call! 

Topics: Particulate Monitoring, Process Control, Flow Control