1 Scope
This standard specifies the technical requirements, test conditions and test methods of on-line instruments for conductivity, pH, sodium ion, dissolved oxygen and silicate in power plants.
This standard is applicable to the acceptance test of the above-mentioned on-line chemical instruments in power plants when they are newly purchased and the measurement test during operation. It may also serve as a reference for laboratory chemical instruments.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6903 Analysis of water used in boil and cooling system—General rule
GB/T 12148 Methods for analysis of water for boiler and for cooling—Determination of total silicon—Photometric method by conversion with hydrofluoric acid for low silicon
GB/T 12149 Analysis of water used in boiler and cooling system—Determination of silica—Molybdenum blue colorimetry
GB/T 13966 Terminology for analytical instruments
GB/T 27501 Preparation method of buffer solutions for the measurement of pH value
DL/T 913 Quality inspection guide for water quality analyzers in thermal power plant
JJG 119 Verification regulation of laboratory pH meters
JJG 291 Dissolved oxygen meter with covered-membrane-electrode
JJG 376 Electrolytic conductivity meters
JJG 757 Verification regulation of ionometers
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
on-line chemical instruments
on-line industrial process composition analysis instrument specially used for chemical supervision in the production process of power plants, that is, on-line industrial chemical analysis instrument. In the electric power industry, in order to distinguish electrical measuring instruments from thermal instruments, it is called on-line chemical analysis instruments, referred to as on-line chemical instruments for short
3.2
on-line checking
method for local on-line inspection of on-line chemical instruments, or simulating the normal measurement state of on-line chemical instruments to continuously introduce standard water samples close to the measured water samples into the on-line chemical instruments for accuracy inspection
3.3
operating error
error measured at any point within normal operating conditions
3.4
indication error
difference between the indication value of the instrument and the measured [agreed] true value
3.5
fiducial error
ratio of instrument's indication error to fiducial value
Note: The fiducial value of this standard adopts the maximum value in measuring range.
3.6
maximum value in measuring range—M
minimum value one order of magnitude higher than the standard value of the water sample monitored by the instrument
Note: See Annex A for M values of different water samples.
3.7
display devices fiducial error
ratio of the indication error of the display device to the maximum value in measuring range of the display device
3.8
temperature compensation additional error
error generated when the instrument is used under non-standard conditions, called additional error. In order to test the self compensation performance of the instrument under different temperature conditions, this index is defined as the temperature compensation additional error
3.9
sample line leakage additional error
relative error of instrument indication value caused by leakage of measurement system
3.10
zero error
error of indication measured by the instrument when the agreed true value is zero
3.11
stability
ability of a measuring instrument to keep its measuring characteristics constant under specified conditions and to keep it constant during continuous operation within a certain period of time (24h)
3.12
repeatability
degree of consistency of a series of results measured by using the same method, the same specimen and under the same conditions. The same conditions include the same operator, the same instrument, the same laboratory and a short time interval
Note: Repeatability represents the random error of instrument, excluding drift and backlash.
3.13
indication of a measuring instrument
value measured and displayed by the measuring instrument
3.14
standard material
material with sufficient accuracy to calibrate or verify instruments, evaluate measurement methods or assign values to other materials
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Quality acceptance of on-line chemical instruments
5 On-line conductivity meter
5.1 Technical requirements
5.2 Test conditions
5.3 Test equipment and standard solution
5.4 Test for the complete machine error
5.5 Test for display device
5.6 Test for electrode constant
5.7 Test for exchange column additional error
5.8 Test for temperature measurement error
6 On-line pH meter
6.1 Technical requirements
6.2 Test conditions
6.3 Test equipment and standard solution
6.4 Test for complete machine error
6.5 Test for display device
6.6 Test for temperature measurement error
6.7 Test for electrode performance
7 On-line sodium meter
7.1 Technical requirements
7.2 Test conditions
7.3 Test equipment and standard solution
7.4 Test for complete machine error
7.5 Test for display device indication error
8 On-line dissolved oxygen meter
8.1 Technical requirements
8.2 Test conditions
8.3 Test equipment and standard solution
8.4 Test for complete machine error
8.5 Test for zero error
8.6 Test for temperature influence additional error
8.7 Test for sample line leakage additional error
9 On-line silicon meter
9.1 Technical requirements
9.2 Test conditions
9.3 Standard solution
9.4 Test for the complete machine error
9.5 Test for repeatability of complete machine
9.6 Anti phosphate interference performance test
Annex A (Normative) Maximum value M in measuring range
Annex B (Normative) Preparation method of conductivity standard solution
Annex C (Informative) Record format of on-line conductivity meter test results
Annex D (Informative) Preparation device for low conductivity standard water sample
Annex E (Normative) Preparation method of pH standard buffer solution
Annex F (Informative) Record format of on-line pH meter test results
Annex G (Normative) Preparation and preservation of sodium standard solution
Annex H (Informative) Record format of on-line sodium meter test results
Annex I (Informative) Preparation device for low concentration dissolved oxygen standard water sample
Annex J (Informative) Record format of on-line dissolved oxygen meter test results
Annex K (Normative) Preparation method of silicon dioxide standard solution
Annex L (Informative) Record format of on-line silicon meter test results
1 Scope
This standard specifies the technical requirements, test conditions and test methods of on-line instruments for conductivity, pH, sodium ion, dissolved oxygen and silicate in power plants.
This standard is applicable to the acceptance test of the above-mentioned on-line chemical instruments in power plants when they are newly purchased and the measurement test during operation. It may also serve as a reference for laboratory chemical instruments.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 6903 Analysis of water used in boil and cooling system—General rule
GB/T 12148 Methods for analysis of water for boiler and for cooling—Determination of total silicon—Photometric method by conversion with hydrofluoric acid for low silicon
GB/T 12149 Analysis of water used in boiler and cooling system—Determination of silica—Molybdenum blue colorimetry
GB/T 13966 Terminology for analytical instruments
GB/T 27501 Preparation method of buffer solutions for the measurement of pH value
DL/T 913 Quality inspection guide for water quality analyzers in thermal power plant
JJG 119 Verification regulation of laboratory pH meters
JJG 291 Dissolved oxygen meter with covered-membrane-electrode
JJG 376 Electrolytic conductivity meters
JJG 757 Verification regulation of ionometers
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
on-line chemical instruments
on-line industrial process composition analysis instrument specially used for chemical supervision in the production process of power plants, that is, on-line industrial chemical analysis instrument. In the electric power industry, in order to distinguish electrical measuring instruments from thermal instruments, it is called on-line chemical analysis instruments, referred to as on-line chemical instruments for short
3.2
on-line checking
method for local on-line inspection of on-line chemical instruments, or simulating the normal measurement state of on-line chemical instruments to continuously introduce standard water samples close to the measured water samples into the on-line chemical instruments for accuracy inspection
3.3
operating error
error measured at any point within normal operating conditions
3.4
indication error
difference between the indication value of the instrument and the measured [agreed] true value
3.5
fiducial error
ratio of instrument's indication error to fiducial value
Note: The fiducial value of this standard adopts the maximum value in measuring range.
3.6
maximum value in measuring range—M
minimum value one order of magnitude higher than the standard value of the water sample monitored by the instrument
Note: See Annex A for M values of different water samples.
3.7
display devices fiducial error
ratio of the indication error of the display device to the maximum value in measuring range of the display device
3.8
temperature compensation additional error
error generated when the instrument is used under non-standard conditions, called additional error. In order to test the self compensation performance of the instrument under different temperature conditions, this index is defined as the temperature compensation additional error
3.9
sample line leakage additional error
relative error of instrument indication value caused by leakage of measurement system
3.10
zero error
error of indication measured by the instrument when the agreed true value is zero
3.11
stability
ability of a measuring instrument to keep its measuring characteristics constant under specified conditions and to keep it constant during continuous operation within a certain period of time (24h)
3.12
repeatability
degree of consistency of a series of results measured by using the same method, the same specimen and under the same conditions. The same conditions include the same operator, the same instrument, the same laboratory and a short time interval
Note: Repeatability represents the random error of instrument, excluding drift and backlash.
3.13
indication of a measuring instrument
value measured and displayed by the measuring instrument
3.14
standard material
material with sufficient accuracy to calibrate or verify instruments, evaluate measurement methods or assign values to other materials
Contents of DL/T 677-2018
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Quality acceptance of on-line chemical instruments
5 On-line conductivity meter
5.1 Technical requirements
5.2 Test conditions
5.3 Test equipment and standard solution
5.4 Test for the complete machine error
5.5 Test for display device
5.6 Test for electrode constant
5.7 Test for exchange column additional error
5.8 Test for temperature measurement error
6 On-line pH meter
6.1 Technical requirements
6.2 Test conditions
6.3 Test equipment and standard solution
6.4 Test for complete machine error
6.5 Test for display device
6.6 Test for temperature measurement error
6.7 Test for electrode performance
7 On-line sodium meter
7.1 Technical requirements
7.2 Test conditions
7.3 Test equipment and standard solution
7.4 Test for complete machine error
7.5 Test for display device indication error
8 On-line dissolved oxygen meter
8.1 Technical requirements
8.2 Test conditions
8.3 Test equipment and standard solution
8.4 Test for complete machine error
8.5 Test for zero error
8.6 Test for temperature influence additional error
8.7 Test for sample line leakage additional error
9 On-line silicon meter
9.1 Technical requirements
9.2 Test conditions
9.3 Standard solution
9.4 Test for the complete machine error
9.5 Test for repeatability of complete machine
9.6 Anti phosphate interference performance test
Annex A (Normative) Maximum value M in measuring range
Annex B (Normative) Preparation method of conductivity standard solution
Annex C (Informative) Record format of on-line conductivity meter test results
Annex D (Informative) Preparation device for low conductivity standard water sample
Annex E (Normative) Preparation method of pH standard buffer solution
Annex F (Informative) Record format of on-line pH meter test results
Annex G (Normative) Preparation and preservation of sodium standard solution
Annex H (Informative) Record format of on-line sodium meter test results
Annex I (Informative) Preparation device for low concentration dissolved oxygen standard water sample
Annex J (Informative) Record format of on-line dissolved oxygen meter test results
Annex K (Normative) Preparation method of silicon dioxide standard solution
Annex L (Informative) Record format of on-line silicon meter test results
