GB/T 19494.1-2023 PDF English
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| GB/T 19494.1-2023 | English | 440 |
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Mechanical sampling of coal - Part 1: Method for sampling
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| GB/T 19494.1-2004 | English | 165 |
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Mechanical sampling of coal -- Part 1: Method for sampling
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GB/T 19494.1-2023: Mechanical sampling of coal - Part 1: Method for sampling---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT19494.1-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 73.040
CCS D 21
Replacing GB/T 19494.1-2004
Mechanical Sampling of Coal - Part 1.Method for Sampling
(ISO 13909-1.2016, Hard coal and coke - Mechanical sampling - Part 1.General
introduction; ISO 13909-2.2016, Hard coal and coke - Mechanical sampling - Part 2.
Coal - Sampling from moving streams; ISO 13909-3.2016, Hard coal and coke -
Mechanical sampling - Part 3.Coal - Sampling from stationary lots, NEQ)
Issued on. NOVEMBER 27, 2023
Implemented on. MARCH 1, 2024
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
Introduction... 4
1 Scope... 5
2 Normative References... 5
3 Terms and Definitions... 5
4 General Requirements and Precision of Sampling... 9
5 Establishment of Sampling Schemes... 10
6 Moving Coal Flow Sampling Method... 19
7 Stationary Coal Sampling Method... 27
8 Packaging and Marking of Coal Sample... 33
9 Sampling Report... 34
Appendix A (informative) Examples of Calculation of the Number of Sampling Units
and the Number of Increments in Each Sampling Unit... 35
Appendix B (normative) Evaluation of Mass-basis Sampling Equipment... 37
1 Scope
This document specifies the general requirements and precision of mechanized coal sampling,
the establishment of sampling schemes, the moving coal flow sampling method and stationary
coal sampling method, as well as packaging and marking of coal samples, and sampling reports.
This document is applicable to lignite, bituminous coal and anthracite coal.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 3715 Terms Relating to Properties and Analysis of Coal
GB/T 19494.2 Mechanical Sampling of Coal - Part 2.Method for Sample Preparation
GB/T 19494.3 Mechanical Sampling of Coal - Part 3.Determination of Precision and Bias Test
3 Terms and Definitions
What is defined in GB/T 3715, and the following terms and definitions are applicable to this
document.
3.1 coal sample
A representative portion of coal taken for the purpose of determining certain properties.
3.2 test sample of coal
Sample prepared to satisfy specific test requirements.
3.3 common sample of coal
Coal sample taken for multiple tests.
3.4 moisture sample of coal
Coal sample specially taken for the determination of total moisture.
3.6 size analysis sample of coal
Coal sample taken specifically for particle size analysis.
3.7 sampling
The process of taking a representative portion of coal from a large amount of coal.
3.8 increment
A sample taken by operating the sampling device once or intercepting a full cross-section of the
coal flow.
3.9 primary increment
An increment taken during the first stage of sampling, before any reduction or division.
3.14 lot
An independent quantity of coal, for which, bulk properties need to be determined.
3.15 continuous sampling
Take a gross sample from each sampling unit in a lot of coal. During sampling, the increment
points are distributed at even intervals.
3.16 systematic sampling
Take increments at the same time, space or mass intervals, but the first increment is taken
randomly within the first interval, and the remaining increments are taken at selected intervals.
3.31 relevant bias
A bias that is of practical importance or agreed by all parties to the contract.
4 General Requirements and Precision of Sampling
4.1 General Requirements for Sampling
The purpose of coal sampling and sample preparation is to obtain a test sample of coal whose
test results can represent the entire lot of sampled coal.
4.2 Precision
In principle, sampling schemes can be designed to achieve any level of precision.
Formula (1) is the precision estimation formula during continuous sampling, and its relevant
theory is described in GB/T 19494.3.
5 Establishment of Sampling Schemes
5.1 Basic Procedures of Establishing Sampling Schemes
The basic procedures of establishing sampling schemes are as follows.
5.2 Design of Sampling Procedures
5.2.1 Determination of sampling object and type of specimen
The first step in designing a sampling scheme is to determine the coal to be sampled, including
the source, variety, original production (or use) coal / new production (or use) coal, lot size of
sampled coal, nominal top size and quality history.
5.2.2 Determination of Sampling Precision
The sampling precision is determined based on the purpose of sampling, the type of specimens
and the requirements of all parties to the contract. In the absence of agreement, the precision
can be determined with reference to Table 1.
5.2.3 Determination of coal variability
5.2.3.1 Determination of variance of primary increments
The variance of primary increments depends on the variety of coal, the nominal top size, the
degree of processing and mixing, the absolute value of the parameter to be measured and the
mass of increments.
5.2.3.2 Sample preparation and assay variance
The variance of sample preparation and assay VPT is obtained through one of the following
methods.
5.2.4 Number of sampling units and number of increments
5.2.4.1 Overview
Theoretically speaking, the number of increments taken from a lot of coal to obtain a specific
sampling precision is a function of the quality variability of that lot of coal, which has nothing
to do with the size of that lot of coal. However, in practice, due to the serial correlation of coal,
it is related to the quantity of coal.
5.2.4.2 Determination of number of sampling units and number of increments with known
VI and VPT
6 Moving Coal Flow Sampling Method
6.1 General Rules
The moving coal flow sampling is carried out in a time-basis or mass-basis systematic sampling
mode or a stratified random sampling mode. From the perspective of operational convenience
and economy, time-basis sampling is preferred.
6.2 Systematic Sampling
6.2.1 Time-basis sampling
6.2.1.3 Mass of increment
The mass of the increment is proportional to the coal flow rate. The average mass of primary
increments and the absolute mass of primary increments shall be greater than the values
calculated through Formula (12) and Formula (13).
6.2.2 Mass-basis sampling
6.2.2.1 Primary increment collection method
The primary increments are collected at preset mass intervals. The first increment is randomly
taken within the first mass interval, and the remaining increments are taken at equal mass
intervals. Variable-velocity or fixed-velocity samplers can be used for sampling. If the pre-
calculated number of increments has been collected, but the coal flow in the sampling unit has
not finished, then, sampling shall continue at the same mass interval, until the coal flow finishes.
6.3 Stratified Random Sampling
6.3.1 Basic requirements
The quality of coal may periodically change during the sampling, and its change period shall
not coincide with the increment collection period, otherwise, it may cause unacceptable
sampling bias. For this purpose, stratified random sampling can be adopted.
6.3.2 Time-basis stratified random sampling
In accordance with the stipulations of 6.2.1.2 and 6.2.1.3, respectively calculate the sampling
time interval and increment mass.
6.4 Reference Sampling
The reference method for coal flow sampling is the stop-belt sampling method, which is only
used when conducting sampling system error tests. This method shall comply with the
stipulations of GB/T 19494.3.
6.5 Moving Coal Flow Sampling Machinery
6.5.1 Basic requirements
The basic conditions for mechanized samplers are as follows.
6.5.2 Design of downflow samplers
6.5.2.1 Basic requirements
The sample cutter shall satisfy the following requirements.
7 Stationary Coal Sampling Method
7.1 Overview
This clause mainly applies to full depth and deep stratified sampling of coal carried by trains,
cars and shallow barges. A sampling unit can be a train, one or several carriages, one or several
barges.
7.2 Collection of Increments
The increments are collected using the sampler specified in 7.4.During sampling, the sampler
shall be inserted into the coal to take a full-depth coal pillar of increment from the top to the
bottom, or it shall be inserted into the coal to a certain depth and take out a stratified increment
when it can ensure that the quality of coal in the carrier is uniform and there is no stratified
loading of coal with different qualities; during sampling, large blocks of coal, hard coal or rocks
that shall be collected shall not be pushed away, and wet coal shall not stick to the sampler.
7.3 Distribution of Increments
7.3.1 Sampling on trains
7.3.2.2 Selection of increment position
The selection of increment position is the same as sampling on trains (see 7.3.1.2).
7.3.3 Sampling on barges
The increment distribution of sampling on barges is, in principle, the same as that of sampling
on trains (see 7.3.1). Sampling on barges can be carried out in accordance with the stipulations
of 7.2 and 7.3.
7.3.6 Random collection method of increments
7.3.6.1 Selection of carriages / barges for sampling
Number the carriages / barges of the entire sampling unit, make and number the number of
plates equal to the total number of carriages / barges, and one plate corresponds to one carriage
/ barge.
7.4 Stationary Coal Sampling Machinery
7.4.1 Basic requirements
Any stationary coal sampling machinery that satisfies the stipulations of 6.5.1 can be used.
Before using the stationary coal sampling machinery, a bias test shall be carried out in
accordance with the method specified in GB/T 19494.3, and it can only be used after it is proved
that there is no relevant bias.
7.4.2 Example
Commercial sampling machinery, to which, stationary coal sampling applies, is shown in Figure
4 and Figure 5.
8 Packaging and Marking of Coal Sample
The coal sample shall be packed in non-absorbent, non-corrosive sealed containers, and with a
permanent unique identification mark.
The following information shall be included in the coal sample label or accompanying
documents.
9 Sampling Report
The sampling shall have a formally issued, comprehensive sampling, sample preparation and
specimen delivery report or certificate.
In addition to providing all the information specified in Chapter 8, the sampling report or
certificate shall also include the following contents.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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