JJG 291-2018_English: PDF (JJG291-2018)
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Dissolved Oxygen Meters
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Verification regulation of dissolved oxygen meter with covered-membrane-electrode
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Verification Regulation of Film Electrode Dissolved Oxygen Meter
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Standard ID | JJG 291-2018 (JJG291-2018) | Description (Translated English) | Dissolved Oxygen Meters | Sector / Industry | Metrology & Measurement Industry Standard | Word Count Estimation | 19,130 | Date of Issue | 2018-02-27 | Date of Implementation | 2018-08-27 | Older Standard (superseded by this standard) | JJG 291-2008 | Drafting Organization | Zhejiang Institute of Metrology, Shanghai Institute of Metrology and Testing Technology | Administrative Organization | National Environmental Chemometrics Technical Committee | Regulation (derived from) | AQSIQ Announcement No. 26 of 2018 | Issuing agency(ies) | State Administration of Quality Supervision, Inspection and Quarantine | Standard ID | JJG 291-2008 (JJG291-2008) | Description (Translated English) | Verification regulation of dissolved oxygen meter with covered-membrane-electrode | Sector / Industry | Metrology & Measurement Industry Standard | Classification of Chinese Standard | A61 | Classification of International Standard | 17.020 | Word Count Estimation | 16,131 | Date of Issue | 2008-12-23 | Date of Implementation | 2009-06-23 | Older Standard (superseded by this standard) | JJG 291-1999 | Drafting Organization | Zhejiang Institute of Standardization | Administrative Organization | National Technical Committee on Environment stoichiometric | Regulation (derived from) | ?AQSIQ Announcement 2008 No.143 | Issuing agency(ies) | State Administration of Quality Supervision, Inspection and Quarantine | Summary | This standard applies to real-time measurement of body surface potential heart-analog single-channel, multi-channel ECG initial verification and subsequent verification, This procedure does not apply to digital ECG machine, vector ECG, ECG and other nonlinear systems and ECG information processing and measuring instruments for special purposes. | Standard ID | JJG 291-1999 (JJG291-1999) | Description (Translated English) | Verification Regulation of Film Electrode Dissolved Oxygen Meter | Sector / Industry | Metrology & Measurement Industry Standard | Classification of Chinese Standard | A61 | Word Count Estimation | 12,166 | Date of Issue | 1999/6/21 | Date of Implementation | 2000/3/15 | Older Standard (superseded by this standard) | JJG 291-1982 | Regulation (derived from) | National AQSIQ Notice 2008 No. 143 |
JJG 291-2018
(Dissolved Oxygen Tester Verification Procedure)
National Metrology Verification Regulations of the People's Republic
Dissolved oxygen analyzer
Published on.2018-02-27
2018-08-27 implementation
The General Administration of Quality Supervision, Inspection and Quarantine issued
Dissolved oxygen analyzer calibration procedures
Replace JJG 291-2008
Focal Point. National Environmental Chemometrics Technical Committee
Main drafting unit. Zhejiang Institute of Metrology
Shanghai Institute of Metrology and Testing Technology
Participated in the drafting unit. China Institute of Metrology
Beijing Aerospace Measurement and Testing Technology Research Institute
Foshan Analyzer Co., Ltd.
This procedure entrusts the National Environmental Chemometrics Technical Committee to explain
The main drafters of this procedure.
Lin Wei (Zhejiang Institute of Metrology)
Xu Yuan (Zhejiang Institute of Metrology)
Wang Zhentao (Shanghai Institute of Metrology and Testing Technology)
Participate in the drafters.
Xiu Hongyu (China Institute of Metrology)
Zhang Wei (Zhejiang Institute of Metrology)
Fu Jiale (Shanghai Institute of Metrology and Testing Technology)
Feng Zhijun (Beijing Aerospace Measurement and Testing Technology Research Institute)
table of Contents
Introduction (III)
1 range (1)
2 Overview (1)
3 Metrological performance requirements (1)
3.1 Zero error (1)
3.2 Response time (1)
3.3 Dissolved oxygen concentration indication error (1)
3.4 Repeatability (1)
3.5 Temperature indication error (1)
3.6 Salinity compensation error (1)
4 General technical requirements (1)
4.1 Appearance and Structure (1)
4.2 Signs and logos (1)
5 measuring instrument control (2)
5.1 Verification conditions (2)
5.2 Verification project (2)
5.3 Verification method (3)
5.4 Processing of verification results (4)
5.5 Verification cycle (5)
Appendix A Preparation of certified water (6)
Appendix B Preparation and verification water device structure diagram (7)
Appendix C Oxygen saturation concentration in water at different water temperatures and atmospheric pressures and interpolation method to calculate saturated dissolved oxygen concentration in water
(8)
Appendix D Dissolved Oxygen Analyzer Verification Record (11)
Appendix E Format of the verification certificate/verification result notice (13)
introduction
This procedure refers to HJ506-2009 "Electrochemical Probe Method for Determination of Dissolved Oxygen in Water", ISO 5814.
2012 Water Quality-Determinationof
dissolvedoxygen-Electrochemicalprobemethod), ISO 17289.2014 "Water Dissolved Oxygen
Water quality-Determination of dissolved oxygen-Opticalsensor
Method) and other standards related content, according to JJF1002-2010 "National Metrology Verification Procedures Writing Rules"
Written, compared with JJG 291-2008, in addition to editorial changes, the main content changes are as follows.
--- Added introduction content;
--- Revised the name of the procedure and the scope of application (see cover and scope 1);
---In the overview section, the measurement principle of the coated electrode dissolved oxygen analyzer and the fluorescent dissolved oxygen analyzer is added.
Said (see 2 for an overview);
--- Modified the "repetitive" metrology performance requirements (see 3.4);
--- Removed "insulation resistance" and "insulation strength" technical requirements, verification items, equipment for verification and verification
Method (see 4, 5.1, 5.2, 5.3);
--- Modify the technical indicators such as the barometer index value in the standard and supporting equipment for verification, and increase the sodium chloride
(NaCl) reagent purity requirements (see 5.1.2);
--- Modified the "zero value error" verification method, extending the test time from "5min" to "15min", repair
Changed the "response time" verification method (see 5.3.3, 5.3.4);
--- Change the reference value of dissolved oxygen concentration to look-up table and interpolation method (see 5.3.5);
--- Removed the "Saturation of Concentration Table of Oxygen at Different Temperatures" appendix in the original procedure and "Pure water at different temperatures"
"Saturated Vapor Pressure" appendix adds "saturated concentration of oxygen in water at different water temperatures and atmospheric pressures"
"Appendix" (see Appendix C).
The previous versions of this procedure are released.
---JJG 291-2008;
---JJG 291-1999.
Dissolved oxygen analyzer calibration procedures
1 Scope
This procedure applies to benchtop and portable dissolved oxygen meters with a measurement range of (0~20) mg/L (see below)
The first verification, subsequent verification and in-use inspection of the instrument.
2 Overview
The instrument is primarily used to determine the concentration of dissolved oxygen (DO) in water. The instrument type mainly has a film electrode dissolved
Oxygen analyzer and fluorescence dissolved oxygen meter.
The measuring principle of the coated electrode dissolved oxygen analyzer is the electrochemical probe method. the oxygen sensitive membrane electrode is used to isolate water and
Soluble matter, the potential difference between the electrodes causes the metal ions to enter the solution at the anode, while the oxygen diffuses through the membrane.
Dispersed, reduced at the cathode, and the current produced is proportional to the rate of oxygen transmission through the membrane and electrolyte layer, ie at a certain
The current is proportional to the partial pressure (or concentration) of oxygen in the water. Dissolved oxygen in water by measuring current
concentration. The measurement principle of the fluorescent dissolved oxygen analyzer is mainly based on the quenching effect of oxygen molecules on fluorescent substances. in dissolution
The electrode of the oxygen analyzer is coated with a fluorescent material, and the excitation light is irradiated on the electrode to emit fluorescence, and the fluorescence intensity or annihilation time is long.
Short is related to the concentration of oxygen molecules in water; the higher the concentration of oxygen molecules in water, the smaller the fluorescence intensity, and the more annihilated
fast. The dissolved oxygen concentration in the water can be obtained by measuring the phase difference between the excitation light and the reference light.
The instrument typically consists of an oxygen electrode, an electronic unit, and/or a display unit.
3 Metrological performance requirements
3.1 Zero value error
The zero value error of the instrument should not exceed 0.10mg/L.
3.2 Response time
The response time of the instrument should not exceed 60s.
3.3 Dissolved oxygen concentration indication error
The initial error of the dissolved oxygen concentration indication error of the instrument should not exceed ±0.30mg/L, and the subsequent verification should not exceed
Over ±0.50mg/L.
3.4 Repeatability
The repeatability of the instrument should not exceed 0.15 mg/L.
3.5 Temperature indication error
The temperature indication error of the instrument should not exceed ±0.5 °C.
3.6 Salinity compensation error
The salinity compensation error of the instrument should not exceed ±2%.
4 General technical requirements
4.1 Appearance and structure
......
JJG 291-2008
JJF
National Metrology Technical Specifications
of the People's Republic of China
Dissolved Oxygen Meter with Covered-Membrane-
Electrode
ISSUED ON. DECEMBER 23, 2008
IMPLEMENTED ON. JUNE 23, 2009
Issued by. State Administration for Quality Supervision and Inspection and
Quarantine
Verification Regulation of Dissolved Oxygen
Meter with Covered-Membrane-Electrode
Replacing JJG 291-1999
This regulation was approved by General Administration of Quality Supervision, Inspection
and Quarantine on December 23, 2008 and shall be implemented from June 23, 2009.
Jurisdictional organization.
National Technical Committee on Environmental Stoichiometry
Drafting organization.
Zhejiang Province Institute of Metrology
This regulation is entrusted to and shall be responsibly interpreted by National Technical
Committee on Environmental Stoichiometry.
Drafter of this regulation.
Zhang Yanqun (Zhejiang Province Institute of Metrology)
Table of Contents
1 Scope ... 5
2 Overview ... 5
3 Requirements for metrological performance ... 5
4 General technical requirements ... 5
5 Measuring instrument control ... 6
Annex A Preparation of Water for Verification ... 13
Annex B Structural Drawing of Device for Verification Water Preparation ... 14
Annex C Saturation concentration table of oxygen in water with different temperatures
... 15
Annex D Saturated Vapor Pressure of Pure Water at Different Temperatures... 16
Annex E Verification Record ... 17
Annex F Format of Verification Certificate and Note of Verification Result ... 19
(Inner Page) ... 19
Dissolved Oxygen Meter with Covered-Membrane-Electrode
1 Scope
This regulation applies to initial verification, subsequent verification and in-use verification of
laboratory-service and portable dissolved oxygen meters with covered-membrane-electrode
(hereinafter referred to as the instrument) that have a measuring range of (0 ~ 20)mg/L.
2 Overview
The instrument is used to measure concentration of constant dissolved oxygen meter (DO) in
water.
The instrument is composed of covered-membrane-oxygen electrode, electronic unit and
displayer.
3 Requirements for metrological performance
3.1 Zero error
Zero error of instrument shall not exceed 0.10 mg/L.
3.2 Response time
Response time of instrument shall not exceed 60 s.
3.3 Dissolved oxygen concentration indication error
Dissolved oxygen concentration indication error of instrument for initial verification shall not
exceed ±0. 30 mg/L; indication error for subsequent verification shall not exceed ±0. 50 mg/L.
3.4 Repeatability
Standard deviation of instrument for initial verification shall not exceed 0.15 mg/L; standard
deviation for subsequent verification shall not exceed 0.20 mg/L.
3.5 Temperature indication error
Temperature indication error of instrument shall not exceed ± 0. 5°C.
3.6 Salinity compensation error
Salinity compensation error of instrument shall not exceed ± 2 %.
4 General technical requirements
4.1 Appearance
4.1.1 The instrument shall indicate the name of manufacturing company, model and
manufacturing number; domestic instrument shall be marked with metering equipment
referring to Annex D, in Pa. Take △c with maximum absolute value as dissolved oxygen
concentration indication error.
5.3.7 Verification of repeatability
5.3.7.1 Verification of repeatability of instrument shall be carried out in saturated dissolved
oxygen water that thermostatic water batch is close to the room temperature.
5.3.7.2 Measure table saturated dissolved oxygen water for continuous 6 times; record 5.3
Verification method
5.3.1 Appearance
Check through vision or hand feeling according to requirements of 4.1.
5.3.2 Verification of insulation resistance
The instrument is not connected to power source. Turn on the power switch. Connect one end
of insulation resistance meter to the phase of instrument input terminal and neutral conjunction
line, while connect the other end to protective earth terminal (or shell) of the instrument. Apply
test voltage of 500 V and continue for 5 s; measure insulation resistance.
5.3.3 Verification of dielectric strength
The instrument is not connected to power source. Turn on the power switch. Connect two
measuring lines of dielectric strength tester to phase of power input terminal, central
conjunction line and ground terminal (or shell). Apply test voltage of 1 500 V; set leak current
to be 5 mA and lifting time to be (5s to 20)s; keep for 1 min, and then lower the voltage to 0
V stably. There shall be no breakdown and arcing phenomena during the test process.
5.3.4 Verification zero error
5.3.4.1 Calibrate normally according to the requirements of operation instruction of instrument.
5.3.4.2 Immerse electrode into freshly prepared oxygen-free solution at a temperature of
(20±5)°C from air; see A.1 in Annex A for preparation of anaerobic water.
5.3.4.3 Instrument indication after 5 min is just the zero error caused by zero bit current.
5.3.5 Verification of response time
5.3.5.1 Control thermostatic water bath temperature to (20±1)°C; prepare saturated dissolved
oxygen water according to requirements in A.2 of Annex A.
5.3.5.2 Take electrode out of thermostatic water bath and immerse into oxygen-free water
quickly; meanwhile start timing.
5.3.5.3 Stop timing when the instrument displays 90% stable value; the reading of stopwatch
is just the response time.
5.3.6 Verification of dissolved oxygen concentration indication error
5.3.6.1 Re-calibrate the instrument.
instrument according to Formula (4).
)4...(...si
Where,
Ti - Instrument indication temperature value, in °C;
Ts - Reading of precision thermometer, in °C.
Take △T with maximum absolute value as instrument temperature indication error of
instrument.
5.3.9 Verification of salinity compensation error
5.3.9.1 Pour 1 L of distilled water into the beaker; place it into thermostatic water bath at a
temperature of (15±0.2)°C; stop bubbling 1 h after the start; still for 10 min and measure
concentration N0 of dissolved oxygen concentration with zero salt. Standard value of water
dissolved oxygen concentration that salt content is n(g/L) is obtained according to Formula (5).
)5...(...9055.0-0sn nNN
Where,
n - Salt (NaCl) in grams, n may be 10g, 20g and 30g.
Note. 0.055 9 refers to the variation of solubility when water temperature is 15°C and salt content is 1 g/L
(△Cs). See Annex A of GB/T 11913- 1989.
5.3.9.2 Maintain pure water temperature 15°C; add salt of 10 g and stir uniformly; prepare it to
be saturated dissolved oxygen water that salt content is 10 g/L and measure to get N10
(measure for 2 times and take the average value). Use the same method to prepare water into
saturated dissolved oxygen water that salt content is 20, 30 g/L and measure to get N20 and
N30 respectively. Calculate salinity compensation error according to Formula (6).
߂ܰ ൌ ܰିܰ௦ܰୱ ൈ 100% ... (6)
Where,
Nn - Concentration of saline dissolved oxygen, which may be N10, N20, N30, in mg/L.
Take the △N with the maximum absolute value as salinity compensation error of instrument.
5.4 Verification results handling
5.4.1 In case of poor electrode performance discovered during verification process, it is
allowed to replace electrode electrolyte and membrane; re-verification is required after the
replacement.
5.4.2 Issue verification qualification certificate for instruments that are verified qualified
according to this regulation. For disqualified instruments, issue notice of verification results,
Annex F
Format of Verification Certificate and Note of Verification Result
(Inner Page)
F.1 Format of verification certificate (inner pages)
Verification Item Technical Requirements Verification Results
Appearance
Zero error
Insulation resistance
Dielectric strength
Response time
Dissolved oxygen concentration
indication error
Repeatability
Temperature indication error
Salinity compensation error
F.2 Format of notice of verification result (inner pages)
Verification Item Technical Requirements Technical Results
Conclusion of Single
Item
Appearance
Insulation resistance
Dielectric strength
Zero error
Response time
Dissolved oxygen indication error
Repeatability
Temperature indication error
Salinity compensation error
Disqualified item.
......
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