Saw thickness impact on cotton gin energy consumption

Authors: Funk, Paul; Thomas, Joseph; Yeater, Kathleen; Armijo, Carlos; Whitelock, Derek; Wanjura, John; Delhom, Christopher

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2021
Publication Date: 2/17/2022
Citation: Funk, P.A., Thomas, J.W., Yeater, K.M., Armijo, C.B., Whitelock, D.P., Wanjura, J.D., Delhom, C.D. 2022. Saw thickness impact on cotton gin energy consumption. Applied Engineering in Agriculture. 38(1):15-21. https:///doi.org/10.13031/aea.14535.
DOI: https://doi.org/10.13031/aea.14535

Interpretive Summary: Seed-fiber separation for 95% of US cotton is accomplished in a saw gin by gin saw teeth pulling the fiber between closely spaced metal ribs where the seeds cannot fit. Historically, gin saws have been produced in three thicknesses. The US cotton ginning industry sometimes would change the thicknesses of the saws in a gin stand to increase their longevity. Industry was aware that there may be differences in processing rate and energy consumption because of differences in saw thickness, but these economically important variables had not been compared. This is the first research to report the effect that changing to thicker saws might have on a saw gin stand designed to work using thinner ones. Processing rate decreased approximately ten percent and electrical energy consumption for seed-fiber separation increased approximately 35 percent. This result provides quantitative evidence to support guidance to the US cotton ginning industry recommending that they avoid this type of equipment modification.

Technical Abstract: Most cotton fiber (lint) is separated from the seed by gin saw teeth that pull the lint between metal bars (ribs). These ribs are close enough to the saws that the seeds cannot pass with the lint. Cotton gin saws are available in three thicknesses, 0.9144, 0.9398, and 1.143 mm (0.036, 0.037, and 0.045 in.). No data from controlled experiments has been published which compares the effect of saw thickness on the economically important performance measures gin processing rate and energy consumption. Two cylinders were stacked with 406 mm (16 inch) diameter saws of 0.9144 and 1.143 mm thickness and tested on a reduced-width (46-saw) Continental Double Eagle gin stand with constant rib spacing at the USDA-ARS Southwestern Cotton Ginning Research Laboratory in Las Cruces, New Mexico. Energy consumption was recorded for target processing rates 4.88 and 6.08 g saw-1 sec-1 using pre-cleaned seed cotton grown in New Mexico, Texas, and Mississippi in a randomized complete block experiment with five replicates. Power factor was constant from 120% to 157% of full load amps. On this equipment we found that the thicker saw cylinder averaged 90% (4.692 g saw-1 sec-1) the processing rate of the thinner saws (5.213 g saw-1 sec-1). Net ginning energy of the 1.143 mm gin saws was 26.5 W-h kg-1 compared to 19.7 W-h kg-1 for the 0.914 mm saws, or about 35% more energy. Thicker saws are less likely to break under harsh conditions at the ends of the gin stand and are still recommend for use there, but there appears to be no advantage to installing thicker saws across the full width.