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Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings Publication Acceptance Date: 1/19/2000 Publication Date: 6/19/2000 Citation: BARKER, G.L., PELLETIER, M.G., LAIRD, J.W., BRASHEARS, A.D. EVALUATION OF MASS FLOW RATE SENSORS FOR STRIPPER HARVESTED COTTON. PROCEEDINGS OF THE BELTWIDE COTTON CONFERENCE. 2000. V. 2. P. 1574-1577. Interpretive Summary: Process control has the potential of eliminating labor requirements, and thus reducing costs, when utilized in the processing industry. In addition, orderly shut down of processing equipment would reduce both machine damage and down time. Process control requires accurate knowledge of detailed process parameters such as mass, flow rates, moisture, and other similar state variables. In the ginning industry, one of the major unknowns, as cotton moves through the system, is the instantaneous measure of the mass of cotton, seed, lint, and trash. Most of the conveying in current cotton gins is done by pneumatic means, which makes the measurement of mass flow rates by conventional means, such as scales, very difficult. The resilient nature of the cotton also eliminates the types of devices used for grain. Thus, we began a project to evaluate the applicability of belt scales, light bar arrays and a microwave based sensor to measure the mass flow of cotton in pneumatic ducts. The microwave based sensor was unsuitable for measuring mass flow, but did provide an excellent indication of the presence of flow in the pneumatic pipes. The signal from the light bar array correlated very well with the mass flow rate of the cotton through the pipes (R2 = 0.98) and requires only minor modifications in the conveyance system. All devices need estimates of moisture and trash content to improve accuracy. Mechanical problems were encountered with the scales which made it impossible to vary rate. However, the belt scales correlated very well with the signal from the truck scales. Technical Abstract: Mass flow sensors are needed at various locations in the cotton gin if process control is to reach its full potential. Several devices, including belt scales, light array bars, and a microwave flow meter were evaluated for their suitability in detecting the flow of cotton and the mass flow rates of stripper harvested cotton. The readout from the truck scales was used to provide the lot weight for the study. Although equipment problems prevented us from testing the accuracy of the scale units under varying rate conditions, these units should provide the most accurate method of measuring mass flow. The mechanical nature of the scale units, however, limits their usefulness in commercial gins which use primarily pneumatic systems to convey the cotton. The microwave based sensor was unsuitable for measuring mass flow, but did provide an excellent indication of the presence of flow in the pneumatic pipes. The signal from the light bar array correlated very well with the mass flow rate of the cotton through the pipes (R2 = 0.98) and requires only minor modifications in the conveyance system. All devices need estimates of moisture and trash content to improve accuracy. |
