Use of Pressured-Air for Cotton Lint Cleaning

Saw-type lint cleaner (STLC) was most efficient lint cleaner in cotton ginning. However, STLC damaged fiber quality. An air-bar lint cleaner (ABLC) was developed and evaluated to preserve cotton fiber quality. The ABLC used pressurized-air to remove non-lint materials from cotton fiber. During lint cleaning process, non-lint materials attached to the fiber were blown off the fiber without the fiber making aggressive mechanical contact with a grid bar in conventional saw-type lint cleaner (STLC). It was expected using this concept that the fiber quality could be preserved by reducing the damage from mechanical impact of the fiber against the grid bar. Preliminary testing of the ABLC prototype showed that ABLC generated less lint waste and had a higher turnout rate than STLC. Use of ABLC could save 2.8 kg of lint in each 225 kg bale of cotton. The High Volume Instrument (HVI) analysis indicated the fiber properties in fiber length, uniformity, short fiber content, and color were not significantly different between ABLC and STLC. However, the Advanced Fiber Information System (AFIS) tests showed STLC had better performance than ABLC in fiber length and short fiber content while the trash and dust content with ABLC was lower than the STLC. More research was necessary to further prove the concept of ABLC and improve its performance in preserving cotton fiber quality.


Introduction
The U.S. cotton industry must improve production efficiency and fiber quality to remain competitive with foreign cotton and synthetic fiber production. Textile mills are demanding higher quality cotton as spinning technology changes and processing rates increase. Improvements in cotton ginning offer significant potential for increasing production efficiency and fiber quality, benefitting the entire industry from producer to textile mill. The introduction and adoption of new technology is crucial and will likely have more impact as gin numbers continue to decline and individual gin capacity continues to increase.
Machine-harvested cotton contained a lot of foreign matters (Funk et al., 2005). In cotton ginning process, cylinder cleaners and stick machines were used to remove the large particles of the foreign matter in seed-cotton before the gin stand to separate cotton fiber and seed. After fiber-seed separation, lint cleaners were used to remove smaller particles that remain in the cotton. Saw-type lint cleaner (STLC) was most efficient lint cleaner in cotton ginning. However, STLC damaged fiber quality by increasing nep level, reducing fiber length, and increasing short fiber content (Thomasson et al., 2007;Gordon & Bagshaw, 2007).
Since cotton fiber quality becomes more and more important in cotton industry, researchers have been working to develop new methodologies and mechanical systems reducing fiber damage and fiber loss while retaining the high efficiency of STLC (Columbus, 1985;Baker, 1987;Hughs et al., 1992;Rutherford et al., 1999). Though performance of STLC was improved using the technologies developed in the researches, the basic cleaning principles remained the same as being developed in the 1940s. Textile mills have placed greater emphasis on fiber quality, particularly related to short fiber content and neps. New principles of lint cleaning need to be investigated to better preserve fiber quality. Sui and Byler (2012) developed a prototype of Air-bar lint cleaner (ABLC). They used commercial nozzle arrays to build an air-bar. The air-bar was mounted in the saw-type lint cleaner replacing the first grid-bar of the cleaner. In operation, the air-bar was connected to pressurizd-air source. Using pressurized airflow, the air-bar removed non-lint materials from cotton fiber while the cotton fiber batt was on a rotating saw cylinder. Thus, non-lint materials attached to the fiber were blown off the fiber without the fiber aggressively making mechanical contact . However, the total trash and dust count with STLC was higher than ABLC. This could be due to pressurized-air effectively removing trash and dust during the lint cleaning process. In the test reported by Sui and Byler (2012), the L(w) and UQL(w) did not differ between their ABLC and STLC, but the ABLC had a lower SFC(w) than the STLC. Note. * Means in rows with the same letter were not significantly different at 0.05 level (n = 29).

HVI Analysis
HVI analysis results were given in Table 2. A one-way ANOVA test indicated the elongation (Elg) and trash count (TrCnt) differed significantly as a function of the lint cleaner (p < 0.05). The other HVI properties were not significantly different between cleaners. The ABLC had higher trash count (22.6) than the STLC (20.7). this result was consistent to the AFIS analysis results. The mean of the micronaire, strength, and UI with both ABLC and STLC were almost the same. SFI were slightly improved with the ABLC, but not significantly. The reflectance (Rd) and yellowness (+b) were about the same with ABLC and STLC. In the report by Sui and Byler (2012), the ABLC significantly reduced SFI (p = 0.0104), and the yellowness (+b) with ABLC was significantly lower than STLC (p < 0.0001). Note. * Means in rows with the same letter were not significantly different at 0.05 level (n = 149). Figure 3 showed the visual comparison of the lint wastes from ABLC and STLC. It is obversed that there was more trash and less lint content in the lint waste with ABLC (Figures 3 and 4). Lint waste rate (LWR) and the turnout were given in Table 3. The LWR with ABLC was significantly lower than that with STLC (P = 0.0002).

Lint Waste
Mean of the LWR with ABLC was 2.1% while it was 3.3% with STLC. This indicated that 2.8kg lint could be saved and added in each 225 kg bale of cotton by using ABLC, which is beneficial to cotton producers. The turnout rate didn't statistically differ between ABLC and STLC (p = 0.7676) though it was slightly higher with ABLC (36.0%) than with STCL (35.7%).
jas.ccsenet.  with the same l howed that the less lint in the ed lint while 5 y higher than t y different from 31.9 g.  Vol. 12, No. 1;2020 Comparing the ABLC reported in this article to the one reported by Sui and Byler (2012), the ABLC reported by Sui and Byler (2012) performed better in preserving fiber quality and reducing amount of cleaned lint in the lint waste. This could be caused by the nozzle size of the air-bar and the air-pressure used in the tests. The nozzle size of the air-bar in the ABLC reported by Sui and Byler (2012) was larger than that used in this study. However, the air-pressure used in this study was 827.4 kPa (120 psi) while it was 413.7 kPa (60 psi) used by Sui and Byler (2012). Airflow force for lint cleaning was a function of the nozzle size and air-pressure. More research was necessary to find the optimal nozzle size and air-pressure for the lint cleaning process.

Figure
There was no difference in MC in the seed-cotton and the lint which were ginned by ABLC and STLC (Table 5).
Mean of the seed-cotton MC was 8.5% and the lint MC was 5.6%. This result indicated that the cotton MC would have no effect on the performance tests of ABLC and STLC. Note. * Means in rows with the same letter were not significantly different at 0.05 level. Note. * Means in rows with the same letter were not significantly different at 0.05 level (n = 18).

Conclusion
A new air-bar device was developed and implemented for an air-bar lint cleaner (ABLC) prototype. The ABLC was tested in comparison with a conventional saw-type lint cleaner (STLC). The ABLC was a new type of lint cleaner that used pressurized-air to assist in removing non-lint materials from lint cotton in ginning process. Preliminary tests of ABLC prototype were conducted. Results showed that ABLC generated less lint waste and had a higher turnout rate than STLC. Use of ABLC could save 2.8 kg of lint in each 225 kg bale of cotton. There was more lint in the lint waste from STLC than that from ABLC. This result was agreed with that reported by Sui and Byler (2012). In HVI analysis, results indicated the fiber properties in length, uniformity, short fiber content, and color were not significantly different between ABLC and STLC. However, the AFIS analysis showed that STLC had better performance than ABLC in fiber length and short fiber content while the trash and dust content with ABLC was lower than STLC. It was noted that some results in AFIS and HVI analysis were not consistent with that reported by Sui and Byler (2012). These could be due to the configuration change of the air-bar and the different air pressures used in the tests. The ABLC used in the test only replaced one grid bar with one air-bar. More than one air-bar could be used in one ABLC, and better performance could be expected with a multi-air-bar lint cleaner. The operating efficiency and effectiveness of ABLC could be affected by many factors including the nozzle size of the air-bar, air-pressure, direction of the airflow, distance between the air-bar nozzles and the saw cylinder. More research is necessary to further prove the concept of ABLC and improve its performance in preserving cotton fiber quality.

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