JJG 2060-2014 PDF in English
JJG 2060-2014 (JJG2060-2014) PDF English
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Verification Scheme of pH(acidity) Measuring Instruments
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Standards related to: JJG 2060-2014
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JJG 2060-2014: PDF in English JJG 2060-2014
JJG
METROLOGICAL VERIFICATION INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
pH (acidity) Measuring instrument
ISSUED ON: AUGUST 25, 2014
IMPLEMENTED ON: FEBRUARY 25, 2015
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC
Table of Contents
Introduction ... 5
1 Scope ... 6
2 Metering reference ... 6
2.1 Reference range and expanded uncertainty ... 6
2.2 Reference measuring device... 6
3 Metering standards ... 7
3.1 pH first-level standard material ... 7
3.2 pH second-level standard material ... 7
3.3 Electrical meter verification device for pH meter ... 7
4 Working measuring instruments ... 8
4.1 Laboratory pH meter ... 8
4.2 Online pH meter ... 8
4.3 Others ... 8
5 Block diagram of verification system of pH (acidity) measuring instrument .. 8
Appendix A Composition of pH first-level standard material and its standard
solution ... 10
Appendix B The pH value of pH first-level standard solution ... 11
pH (acidity) Measuring instrument
1 Scope
This verification system table is suitable for the transfer of pH (acidity)
measuring instruments. It specifies the method and procedure for transferring
the pH (acidity) value from the metering reference to the working measuring
instruments at all levels through metering standard, as well as the optimal
measuring capability when the value is transferred. When carrying out
calibration, it can also be used as a basis for traceability of the value.
2 Metering reference
2.1 Reference range and expanded uncertainty
The national reference is used to reproduce and preserve the pH scale of
aqueous solutions. The range of the national reference reproduced pH ranges
from 0 to 14 (0 °C to 95 °C); the extended uncertainty is 0.005 (k = 3).
The national reference adopts the Harned-cell reference battery method without
liquid junction, which realizes the traceability to the SI basic units of
thermodynamic temperature, current, time, length, mass, etc. through the
measurement of battery potential, temperature, gas pressure, etc.
2.2 Reference measuring device
The reference measuring device consists of the following instruments and
equipment:
Liquid-junction-free reference battery pack (also known as Harned-cell
reference battery pack), which is a liquid-junction-free measurement battery
pack composed of platinum (palladium) hydrogen electrode as indicator
electrode and silver/silver chloride electrode as reference electrode.
The battery potential measuring instrument adopts a DC digital voltmeter which
has a resolution of 1 μV and a maximum allowable error of no more than ±10
μV.
Precision constant temperature water tank: the temperature uniformity of the
constant temperature water tank does not exceed 0.01 °C; the temperature
verification of the instrument, usually the pH meter verification instrument is
used. The measuring range of the pH meter verification device is 0 ~ 14; the
DC voltage range is -2V ~ 2V, which is divided into two levels: 0.003 and 0.0006.
The electrical meter verification device for pH meter composed of a standard
battery and a standard potentiometer shall meet the requirements of the
corresponding level of pH meter verification instrument.
The electrical meter verification device for pH meter transmits the value to the
working measuring instrument through the direct measurement method.
4 Working measuring instruments
Working measuring instruments refer to laboratory pH meters, online pH meters,
as well as the ion meters, potentiometric titrators, water quality analyzers, etc.
used as pH meters.
4.1 Laboratory pH meter
The pH measurement range of the laboratory pH meter is 0 ~ 14; the DC voltage
measurement range is -2 V ~ 2 V, which are divided into 0.001, 0.01, 0.02, 0.1,
0.2 levels.
4.2 Online pH meter
The pH measurement range of the online pH meter is 0 ~ 14; the DC voltage
measurement range is -2 V ~ 2 V, which is divided into 0.01 level and 0.1 level.
4.3 Others
For the ion meters, potentiometric titrators, water quality analyzers, etc. used
as pH meters, it may, based on the pH measurement ranges and accuracy
levels, determine the appropriate pH value transfer path by referring to this
calibration system table.
5 Block diagram of verification system of pH (acidity)
measuring instrument
The block diagram of the pH (acidity) measuring instrument's verification
system is shown in the Figure below.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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