GB/T 17260-2025Determination of fineness of flax - Permeametric methods (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document replaces GB/T 17260-2008 "Determination of Fineness of Flax Fibers - Airflow Method". Compared with GB/T 17260-2008, except for...

Aside from structural adjustments and editorial changes, the main technical changes are as follows.

a) The scope of the document has been changed (see Chapter 1, Chapter 1 of the 2008 edition);

b) The definitions of "fiber cluster" and "fineness standard index" have been changed (see 3.1, 3.5, 2008 edition of 3.1, 3.5), and "cotton-type linen" has been deleted.

Terms and definitions (see 3.6 of the 2008 edition);

c) The regulations for conditioning and testing atmospheres have been amended (see Chapter 4, Chapter 4 of the 2008 edition);

d) The schematic diagram of the constant flow rate method instrument was modified, and the sample mass for the constant flow rate method was changed from "2.95g~3.00g" to "2.80g~".

3.00g (see Chapter 5, 5.1 of the 2008 edition);

e) The schematic diagram of the instrument structure for the simplified constant flow method has been modified. The flow rate of the pump in the simplified constant flow method has been changed from 500 cm³/s to...

250 cm³/s (see Chapter 6, 5.2 of the 2008 edition);

f) A constant pressure sampling method was added, and the result calculation was modified (see Chapter 7, 5.3 of the 2008 edition);

g) The batch sampling method has been removed (see 5.1.2.1, 5.2.2.1, and 5.3.2.1 in the 2008 version);

h) The contents of the test report have been changed (see Chapter 8, Chapter 6 of the 2008 edition);

i) Added conversion of constant pressure method test results (see Appendix C);

j) The calibration and conversion of measurement results for constant pressure airflow meters have been removed (see Appendix C of the 2008 edition).

This document is modified to adopt ISO 2370:2019 "Textiles - Determination of fineness of flax fibers - Airflow method".

This document has undergone significant structural adjustments compared to ISO 2370:2019.A table comparing the structural numbering changes between the two documents is provided.

See Appendix A.

The technical differences between this document and ISO 2370:2019, and the reasons therefor, are as follows.

---ISO 139 (see Chapter 4) has been replaced with the normatively referenced GB/T 6529 to adapt to my country's technical conditions and improve operability.

Actual nature;

---The sampling method based on ISO 1130 (see ISO 2370:2019 sections 5.2, 6.2, and 7.2) has been removed to align with existing standards.

Improve operability;

---Sample preparation details the sampling methods for hemp fibers that have been beaten or combed (see 5.3.1, 6.3.1, 7.3.1, and 5.3.2.1 of ISO 2370:2019).

6.3.2.1, 7.3.2.1), hemp strip sampling method (see 5.3.3, 5.3.2.3 of ISO 2370:2019);

---The instrument function check procedures have been simplified (see 5.4.1, 6.4.1, 7.4.1, and ISO 2370:2019 sections 5.6, 6.6, and 7.6), improving operability.

To eliminate differences;

---The rounding rules for the calculation results follow GB/T 8170 (see 5.5, 6.5, 7.5; ISO 2370:2019 5.7, 6.7, 7.7), to be consistent with...

To harmonize with existing standards and improve operability.

The following editorial changes have been made to this document.

---To align with existing standards, the standard name has been changed to "Determination of Flax Fiber Fineness by Airflow Method".

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed and is under the jurisdiction of the National Technical Committee on Standardization of Fibers (SAC/TC513).

1 Scope

This document describes three methods for determining the fineness of flax fibers using the airflow method.

---Constant flow rate method, two compressions, using parallel fiber samples (see Chapter 5);

---Simplified constant flow method, single compression, using randomly distributed fiber samples (see Chapter 6);

---Constant pressure method, single compression, using randomly distributed fiber samples (see Chapter 7).

This document applies to flax fibers (such as flax pounded into flax, combed into flax, combed into short flax, flax strips, and cotton) produced through processes such as degumming and carding.

(e.g., flax), and the fineness determination of different fiber forms during their processing.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 6529 Standard atmosphere for conditioning and testing of textiles (GB/T 6529-2008, ISO 139:2005, MOD) GB/T 8170 Rules for rounding off numerical values and the representation and determination of limiting values

3 Terms and Definitions

The following terms and definitions apply to this document.

Fiber clusters wadoffibre the fiber sample to be tested is placed in the central channel of the cylindrical sample tube.

Note. In the constant flow rate method, the fibers forming the fiber clusters are parallel to the axis of the sample cylinder. In the simplified constant flow rate method and the constant pressure method, the fibers forming the fiber clusters are random.

Arrangement. Of these three methods, it is crucial to ensure that the filling density is as uniform and regular as possible.

The ratio of the pressure drop deltap (hPa) caused by airflow passing through the fiber cluster to its flow rate Q (cm3/s).

Note. The unit is expressed in hectopascals per cubic centimeter (hPa·s/cm3).

The ratio of the total lateral surface area of the fiber bundles that make up the fiber cluster to their volume.

Note. The unit is expressed in square centimeters per cubic centimeter (cm2/cm3).

The square root of the product of aerodynamic viscosity (µ) and dimensionless empirical proportionality coefficient (k) is multiplied by the specific surface area of the fiber bundle (A).