SFM - Smart Flow Meters


Defining Calibration

To correlate the readings of an instrument with those of a standard in order to check the instrument's accuracy. 

 With regards to a Smart Flow Meter, this means that you can trust the massflow reading that the controller is displaying. Without calibrating and verifying this process variable, there is no way to know if it's accurate. Gravimetric feeders are expensive. You need to know how to quantify their performance.   

Scale Alignment

Just like a belt feeder, alignment of the internal scales are critical to accuracy and repeatability. When the scales are not installed correctly, material can build up, or jam, causing very large weighing errors.  

Catch Samples

SFMs operate at very high rates, typically 20,000 lbs/hour and above. This makes it very hard to conduct catch samples. The process needs to be setup to facilitate catching and weighing material after the flow meter. This could mean having a divert chute to allow the material to flow into a large box to be weighed later or allowing the entry of material pre-weighed. For example, if you could feed 500 lbs through a SFM that you pre-weighed, you would expect the SFM to show a totalizer value of 500 lbs. This method is not perfect as there could be some error as the product stream starts and stops. 

Span Adjustment

 The span is one of the most important parameters on a Coperion K-Tron Feeder. At 1.000 by default, it offers a way to calibrate the scale. 

For example, if 2000 lbs flowed through the SFM but the totalizer only read 1975, you would adjust the span so the totalizer showed 2000 lbs. 

The span does not correct for scale friction problems or poor feeding materials or other mechanical noise or vibration. 

Best Practice

 To have the best performance from your Coperion K-Tron Feeders you should do the following:

  1. Have an annual calibration by Leming Process Services LLC
  2. Use the factory silicone bellows at the feeder inlets and outlets to minimize feeder vibration from the environment. 
  3. If feeding the SFM with a rotary valve, have it located as close as possible to the SFM.
  4. Keep dust filters clean or use another method of dust collection. 
  5. Keep a weight nearby the feeder so the operators can check the scale before production. 
  6. Educate operators and maintenance in proper operation and handling of the feeders.