Flux Characteristics and Transfer Systems in Electrostatic Application – Part 7

Attachment

Powder Fluidity Indicator

Definition of the Variables and Calculation of the Results

Preliminary remark:
The spraying factor Rm is a relative value for the evaluation of powders used for dry fluxing – especially when the material transport in the used equipment depends on the fluidization property of the powder.
Expansion factor:

Expansion factor [cm/cm] = Hfluid [cm] / H0 [cm]

For the calculation of the expansion factor, the mean values for Hfluid and H0 are used. The data for the mean values results from measurements of the powder height at 5 points.

Hfluid: powder height in fluidized condition
H0: powder height not fluidized and vibrator shut down
Hfluid = (Hfluid1+ Hfluid2+ Hfluid3+ Hfluid4+ Hfluid5) / 5
H0 = (H01 + H02 + H03+ H04+ H05) / 5

Powder flow (m) [g/ 0,5 min]
The mass (weight) of powder flowing out through the calibrated hole in 0.5 minutes calculated as median from 10 measurements.

Calculation of the median:

Median = m9+m2 / 2 for 10 single measures of m and m5< m3< m1< m7< m9< m2< m4< m8< m10< m6

Spray factor (Rm)

Rm [g/ 0.5 min] = m [g/0.5min]* expansion factor

The Spray factor results from the median of powder flow multiplied with the calculated expansion factor.

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