The mass flow rate of pneumatically conveyed seed cotton is a real-time variable required by gin automation devices. Two systems developed to measure mass flow were tested in a commercial gin to determine durability and accuracy. After a two-day calibration period, the instrument-based estimate of mass flow was compared to the mass flow calculated on a bale-by-bale basis. One system failed because of trash particle fouling. The other system provided a mass flow signal that had an 88% correlation to the bale-by-bale calculation after one month of ginning. Analysis is preliminary, but low initial and installation costs coupled with long expected life favor the latter system. modified as follows (Figure 1): Two static rings consisting of six interconnected pressure taps (quarter inch diameter holes) spaced equally around the duct were added, one six feet above the other. The static rings were connected to air tanks of approximately one-gallon volume to dampen fluctuations in the pressure. The tanks were plumbed to either side of a Dwyer 607-21 differential pressure transducer (0.5 inch WG, ±0.25% full scale). Special care was taken to smooth the inside of the duct after drilling, to prevent formation of ‘tags’.

For the velocity pressure system, an S-type Pitot tube was installed in the conveying air duct after the seed cotton separator and suction fan. It was connected to a Dwyer 607-71 differential pressure transducer (5 inch WG, ±0.25% full scale). Both systems’ transducers were connected to a Hewlett Packard 34970A data acquisition/switch unit. Air temperature measured at the S-type Pitot tube and bale press turns (totalizer count) were also monitored. Raw signal values were recorded every ten seconds for 24 hours and retrieved for analysis while the gin was shut down for cleaning. Data were taken from the beginning of October through mid December.