Two evaluations were conducted on a cotton sample opening device designed to operate in conjunction with a High Volume Instrument (HVI) line. The opening device increases the volume of a cotton subsample by mechanically loosening and fluffing the fibers. The subsample used for determination of strength, length and uniformity measurements is the only part of the sample that is passed through the opening device.

The two evaluations involved HVI testing of sets of roller ginned American Pima cotton samples with and without the opening device. The first evaluation utilized four-specimen HVI testing. Results of the first evaluation indicated that the opening device facilitated specimen preparation and improved HVI test precision. The second evaluation compared two-specimen HVI testing with the opening device to four-specimen HVI testing without the opening device. Test precision of four-specimen HVI testing without the opening device was higher than two-specimen HVI testing with the opening device. Although the results of the first evaluation indicated that the opening device improves HVI test precision, the improved precision was not sufficient to overcome the precision difference between two and four-specimen HVI tests.