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D2812-07 – Standard Test Method Technical Guide
📐 Specimen Types and Preparation
The D2812-07 standard provides a method for determining non-lint content in cotton using the Shirley Analyzer. Cotton specimens can be in several forms, as outlined in the scope: (1) raw stock, which is cotton fiber that has been separated from the seed by ginning; (2) partially processed cotton, such as picker lap or sliver; and (3) ginning or processing waste, including material from opening, cleaning, picking, carding, or combing machines. Proper sampling in accordance with Practice D1441 is critical for representative results.
| 🟦 Type | 📏 Description | 🎯 Typical Use |
|---|---|---|
| Raw Stock | Cotton fiber after ginning, unprocessed | Initial quality testing |
| Picker Lap or Sliver | Partially processed cotton in lap or sliver form | In-process control |
| Ginning/Processing Waste | Waste from opening, cleaning, picking, carding, or combing | Waste evaluation |
⚙️ Test Procedure and Operation
The test method involves feeding a known mass of cotton into the Shirley Analyzer. The machine operates on mechanical-pneumatic principles to separate foreign matter from the cotton. Non-lint particles and lint are discharged into separate chambers. The recovered materials are weighed, and the amounts of lint and non-lint are calculated as percentages of the original specimen mass. This procedure is especially adapted for use with the Shirley Analyzer.
💡 Tip: For consistent results, ensure the Shirley Analyzer is properly calibrated and maintained. Follow Practice D1441 for representative sampling to avoid bias between laboratories.
📊 Key Measured Properties
The primary property measured is non-lint content, which includes foreign matter and invisible waste. Lint content is also determined as the complementary fraction. These values are used to assess the purity and quality of cotton. The results, expressed as percentages of the original specimen mass, provide objective data for acceptance testing of commercial shipments and for estimating the net textile yield from raw cotton.
| 📊 Property | ⚡ Definition | 🎯 Importance |
|---|---|---|
| Non-Lint Content | Percentage of non-lint particles (visible and invisible waste) | Indicates cleaning efficiency and purity |
| Lint Content | Percentage of lint fibers recovered | Usable fiber yield for manufacturing |
| Visible Waste | Visible foreign matter separated by the analyzer | Quality assessment in processing |
| Invisible Waste | Non-visible fine particles and dust in the non-lint fraction | Process control and product quality |
⚠️ Warning: Safety hazards may be present during testing. Refer to Section 7 of the standard for specific hazard statements and establish appropriate safety, health, and environmental practices.
❓ Frequently Asked Questions
🔍 What is the scope of D2812-07?
It covers the determination of non-lint content in raw stock, partially processed cotton, and ginning or processing waste using the Shirley Analyzer, with results used for acceptance testing and process evaluation.
💡 How is non-lint content calculated?
The masses of lint and non-lint recovered from the Shirley Analyzer are measured and expressed as percentages of the original specimen mass, as defined in Section 4 of the standard.
⚡ Why is the Shirley Analyzer specified for this test?
This test method is especially adapted for the Shirley Analyzer because it effectively separates foreign matter from lint using mechanical-pneumatic principles, providing repeatable and objective data.
📌 What key terminology is defined in this standard?
Relevant terms include foreign matter, invisible waste, lint, lint content, non-lint content, and visible waste, as referenced in Terminology D7139 for cotton fibers.