Some standard content:
National Metrology Verification Regulations of the People's Republic of China JJG 1044-
Inistrunent for KF Coulometry Titration2008 — 09 - 27 Issued, Published
2009-01-01 Implementation
General Administration of Quality Supervision, Inspection and Quarantine
Main Drafters of this Regulation:
JJG 1044—2008
Wang Lexin (Shandong Institute of Metrology) Lin Zhenqiang (Shandong Institute of Metrology) Wang Yun (Shandong Institute of Metrology) Participating drafters:
Wei (Zibo Huakun Electronic Instrument Co., Ltd.) 1
Scope·
References·
Performance requirements
4.1 Indication error
Measurement repeatability··
Electrolysis speed
Zero balance time
5 General technical requirements||t t||Appearance of the instrument
Electrolytic cell system of the instrument
Circuit system of the instrument
Display system·
Safety index…
Control of measuring instrument
Verification conditions…
Verification items
Verification method
Processing of verification results·
Verification cycle.
Appendix A
Appendix B
Appendix C
Appendix E
Calibration of micro-syringe
JJG 1044—2008
Original inspection record of trace moisture analyzer
Inner page format of inspection certificate
Inner page format of inspection result notice
Preparation of Karl Fischer reagent
(2)
(2))
(3)
(5)
1 Scope
JJG1044-2008
Verification procedure for Karl Fischer coulometric trace moisture analyzer This procedure is applicable to the initial verification, subsequent verification and in-use inspection of Karl Fischer coulometric trace moisture analyzer. It can be used as a reference for the relevant metrological performance requirements and test methods in type evaluation. SDOHNIT
2 References
GB/T7600-1987 "Measurement of moisture content in operating P transformer oil by coulometric method)" The current valid version of the above references should be used. When using this procedure,
3 Overview
Karl Fischer trace moisture meter (hereinafter referred to as the instrument) is mainly used to determine the moisture content in products in the petroleum, chemical, light food and other industries. Its working principle is as follows:
When iodine oxidizes sulfur dioxide, it absorbs water, and Karl Fischer reagent (containing iodine, a mixture of water, pyridine, sulfur dioxide, and anhydrous formazan) reacts with water, and the reaction end point is determined by the electrode method. The chemical equation for the reaction of Karl Fischer's reagent with water is +SO+3C,HN
-2CHNHI+CH.N
CH.N·SO.+CHOH
CH.N.HSO,CH
Fischer's reagent solution is a mixture of a certain concentration of elemental iodine and anhydrous pyridine filled with sulfur dioxide, and unused Karl Fischer's reagent such as methanol (see Appendix E). The reaction is completed.
iodic acid, until all water is completely
In the electrolysis process
Anode:
Cathode:
Iodine is formed on the anode through electrolysis, and reacts with water to generate oxygen. The end point of the reaction is detected by a pin electrode. The indicator electrode reaction is as follows
2H++2e
In the whole process, the amount of sulfur dioxide consumed is equal to the amount of water. A METROR
According to Faraday's law of electrolysis:
Wherein: W
Water content in the sample, g;
Molar mass of water, g/mol;
Electrolysis charge, C
Faraday constant, C/mol
Number of electron transfer
If the unit of water content in the sample is uμg, the molar mass of water is 18g/mol, the unit of electrolysis charge is mC, and the Faraday constant is 96485C/mol, the calculation formula for the water content in the sample can be simplified to: WX10°6
Wherein: W-—Water content of the sample, μQ electrolysis charge, mC;
\18-—Relative molecular mass of water.
QX10-3
2×96 485
The composition of the Karl Fischer coulometric micro-moisture analyzer is shown in Figure 1. Sampling saddle
Measurement plate pool stirring device
Electrolysis device
Electrode measurement and control device
Electrolysis current integral device
Water display transposition
Figure 1 Block diagram of the composition of the Karl Fischer coulometric micro-moisture analyzer 4 Measurement performance requirements
4.1 Indication error
±(5% calibration point+3).
4.2 Measurement repeatability
The relative standard deviation (RSD) of the measured value at the 100g point is not more than 3%. 4.3 Electrolysis speed
The measurement time used to electrolyze 1000μg of water is not more than 3min. 4.4 Zero balance time
shall not exceed 2 min,
5 General technical requirements
~ 5.1 Appearance of the instrument
5.1.1 The nameplate of the instrument shall indicate the name, model, manufacturer name, product serial number, date of manufacture, etc. Domestic instruments shall have the license mark of the manufacturing meter. 5.1.2 The appearance of the instrument shall not have mechanical damage that affects the normal operation of the instrument. 5.1.3 All fasteners of the instrument shall be tightened and work properly. 5.2 Electrolytic cell system of the instrument
The electrolytic cell system of the instrument shall be well sealed, and the electrodes, dry explosion pipes, and grinding plugs shall be disassembled and assembled smoothly. 5.3 Circuit system of the instrument
5.3.1 The power cord, signal line and other plugs of the instrument shall be tightly plugged in, and the functions of various switches, knobs, buttons, etc. shall be normal, the indicator lights shall be sensitive, and the display shall be clear.
JJG1044—2008
5.3.2 The stirring system of the electrolytic cell is normal and can adjust the speed. 5. 4 Display system
5.4.1 Normally display the measured value of moisture and the change value or change trend of electrolysis speed. 5.4.2 It has the function of using text, code, indicator light or sound to prompt the instrument in the state of zero adjustment, blank test, sample measurement and test results.
5.4.3 It has the function of indicating that the Karl Fischer reagent is iodized and watered. 5.5 Safety indicators
5.5.1 Insulation resistance: The insulation resistance between the power cord and the casing of the instrument is not less than 20M. 5.5.2 Insulation strength: The insulation strength between the power cord and the casing of the instrument can withstand 50Hz, 1500V sinusoidal AC voltage for 1min without breakdown and arcing. 5.5.3 Leakage current: The leakage current between the power cord and the casing of the instrument is not more than 5mA (peak value). 6. Control of measuring instruments
Control of measuring instruments includes initial calibration, subsequent calibration and inspection during use. 6.1 Inspection conditions
6.1.1 Environmental conditions
6.1.1.1 The inspection room should be clean and dust-free, free of flammable, explosive and corrosive gases, and well ventilated; 6.1.1.2 Temperature: (10~30)℃;
6.1.1.3
6.1.1.4
6.1.1.5
Humidity: not more than 80%RH;
Power supply: (220±22)V, (50±1)HztThe instrument should be placed stably on the workbench, without strong mechanical vibration and electromagnetic interference sources around, and the instrument should be well grounded (check equipment
6.1.2.1
6.1.2.2
Record A);
6.1.2. 3
6.1. 2. 4
Stopwatch: the division value is not greater than 0.1S;
Micro syringe: full scale 10μL, 100uL each (the calibration method of micro syringe is shown in the attached analytical balance, the sensitivity is 0.01 mg;
Insulation resistance meter: 500V, 10th level;
6.1.2.5 Withstand voltage tester;
6. 1. 2. 6
Leakage current tester.
Standard materials
Water-methanol standard material (water content 1mg/g, uncertainty 1.4%, k=2); 6. 1. 3. 12
Distilled water.
6. 1. 3.2
Note: Water-methanol standard materials should use certified standard materials approved and issued by the national metrology administrative department. 6.2 Verification items
Verification item requirements are shown in Table 1.
Verification items
Indication error
Repeatability
Electrolysis speed
Zero balance time
Insulation resistance
Insulation strength
Leakage current
Note: 1
2 After maintenance
6.3 Verification method
6.3.1 Preparation before verification
Look at the details;
JJG10442008
First verification
Verification item requirements
Subsequent verification
CENISIH "NSO
" is an item that does not need to be inspected
When it has a great impact on the safety of the instrument, its subsequent verification shall be carried out according to the first verification. Inspection during use
Preheat the instrument according to the instructions. After the instrument is stable, the instrument shall be inspected for the following items. 6.3.2 Verification of general technical requirements
6.3.2.1 Visually and manually inspect according to the requirements of 5.1 and
, and power on and manually inspect according to the requirements of 5.3 and 5.4.
6.3.2.2 Verification of insulation resistance
Apply a 500V DC test voltage between the power cord and the casing. After it stabilizes for 5s, measure the pure insulation resistance
|6.3.2.3 Verification of insulation strength
Use a voltage test device to apply a test voltage of 500V between the power line and the ground line, limit the current to 5mA, and maintain it for 1 minute. Observe whether there is arcing and breakdown, and then steadily drop to zero. 6.3.2.4 Verification of leakage current
Connect a leakage current tester between the power line and the housing, and measure once. Then change the power polarity twice, repeat the measurement, and take the maximum value of the two times, which is the leakage current of the instrument. 6.3.3 Verification of indication error
In the range of (10~5000)μg, select 10, 100, 1000, 5000μg The calibration is carried out around the points. In order to reduce the measurement error, different standard substances and micro-injectors are used for different calibration points (as shown in Table 2). When measuring, first use the required micro-injector to extract the standard substance (or distilled water) to the required scale, weigh the mass W of the injection needle on the analytical balance, and then inject the sample. The injection needle must enter below the electrolyte level. After the sample is completely injected, pull it out, wipe off the electrolyte on the outside of the injection needle, weigh the mass W of the injector, and repeat the measurement 3 times for standard substances with different water contents. The average value of the difference between the measured value and the standard value at the calibration point is the instrument indication error. 4
Water content calibration point
(10~-1000)μg|| tt||JJG1044-2008
Table 2 Different calibration points use different standard materials and micro-injectors Standard materials
1mg/g water methanol
(1.000~5000)pg
The indication error is calculated according to formula (2):
Where: Az
Distilled water
Measurement value of calibration point, ug;
Standard value of calibration point g
Measurement repeatability calibration
Use micro-injector
10L, 100uL, 1ml
When the instrument is stable, use 10L micro-injector to inject 10 concentration as hostage. Continuously inject 6 times!
.g water-methanol standard
Record the water content displayed by the instrument. The quantitative repeatability is expressed as the relative standard deviation RSD of the water content measurement results and calculated according to formula (3):
Where: RSD
Relative standard deviation, %
Number of measurements;
Number of measurement values:
Arithmetic mean of the number of measurements
Injection number
6.3.5 Verification of electrolysis speed
After 1000
is the measurement time. When verifying
Start the titration of the sample with a stopwatch and stop the timer at the end of the titration. 6.3.6 Verification of zero balance time
After the instrument is balanced three times with empty electrolysis, record the time taken by the instrument for empty electrolysis, which is the zero balance time. 6.4 Handling of verification results
METROL
Instruments that pass the verification according to this regulation shall be issued with a verification certificate (the format of the inner page of the verification certificate is shown in Appendix C), and instruments that fail the verification shall be issued with a verification result notice (the format of the inner page of the verification result notice is shown in Appendix D). 6.5 Verification cycle
The verification cycle shall generally not exceed 1 year. If the instrument has been repaired or there is any doubt about the measurement result, it can be verified at any time.
Appendix A
JJG1844—2008
Calibration of micro-syringes
The micro-syringes shall have good airtightness and shall be cleaned and dried before calibration. The mercury used for calibration shall be clean. Calibration method: At room temperature, extract a certain volume of mercury and plug the needle with a silicone rubber pad. Weigh it on an analytical balance of one hundred thousandth of a gram. Then, the mercury is beaten out and weighed again… times. The mass of the mercury can be obtained by subtraction, and then the volume is calculated as follows.
Where: V is the actual volume, ml
the mass of the first weighing, g
V=M,-M2
p water tongs
the mass pan of the second weighing, g;
p ice silver-the density of mercury at room temperature, g/mL. Each volume point is calibrated 6 times: the arithmetic mean is taken. Its relative standard deviation should be within 1%. 6
Appendix B
Inspection unit
Instrument name
Instrument model
Standard name
Measurement range
Verification period
Verifier
Appearance:
Indication error (μg)
Verification point
JJG 1044—2008
Original calibration record of Micro-View Moisture Meter
Address of the testing unit
Manufacturer
Factory abbreviation
Standard substance
Standard value
(W,—W,)
Certificate number of standard instrument
Valid until
Valid until
Verifier
Measured value
Indication error
(Average value）
Repeatability of indication
Electrolysis speed:
Measured value/ug
Zero balance time:
Insulation resistance:
Insulation strength:
Leakage current:
JJG1044—2008
Average value/μg
Relative standard deviation
METROL
Appendix C
Verification environmental conditions:
Verification items
10 μg
Indication error
5000pg
Repeatability (RSD)
Electrolysis speed
Zero balance time
Insulation resistance
Dielectric strength
Leakage current
JJG 1044—2008
Inner page format of verification certificate
Verification results
Technical requirements
Complete markings, functions are in good condition, no damage that affects normal operation
+(5% verification point+3)μg
50 Hz, 1 500 V. Current limit 5 mA, 1 min without breakdown and arcing
Verification results4 Power on and 52
Manual inspection.
6.3.2.2 Verification of insulation resistance
Apply a 500V DC test voltage between the power cord and the housing. After stabilization for 5s, measure the pure insulation resistance
6.3.2.3 Verification of insulation strength
Use a voltage test device to apply a test voltage of 500V between the power cord and the ground terminal, limit the current to 5mA, and maintain it for 1min. Observe whether there is arcing and breakdown, and then steadily drop to zero. 6.3.2.4 Verification of leakage current
Connect a leakage current tester between the power cord and the housing, and unadjust the voltage to 242V. Measure once, then change the power polarity twice, repeat the measurement once, and take the maximum value of the two times, which is the leakage current of the instrument. 6.3.3 Indication error verification
In the range of (10～5000)μg, select 10, 100, 1000, 5000μg or so for verification. To reduce the measurement error, different standard substances and micro-injectors are used for different verification points (as shown in Table 2). When measuring, first use the required micro-injector to extract the standard substance (or distilled water) to the required scale, weigh the mass W of the injection needle on the analytical balance, and then inject the sample. The injection needle must enter below the electrolyte level, and pull it out after all the sample is injected. Wipe off the electrolyte on the outside of the injection needle, weigh the mass W of the injector, and repeat the measurement 3 times for standard substances with different water contents. The average value of the difference between the measured value and the standard value at the verification point is the instrument indication error. 4
Water content calibration point
(10~-1000)μg
JJG1044-2008
Table 2 Different calibration points use different standard materials and micro-injectors Standard materials
1mg/g water methanol
(1.000~5000)pg
The indication error is calculated according to formula (2):
In the formula: Az
Distilled water
Measurement value of the calibration point, ug;
Standard value of the calibration point g
Measurement repeatability calibration
Use micro-injector
10L, 100uL, 1ml
When the instrument is stable, use 10L micro-injector to inject 10 concentration hostage. Continuous injection 6 times!
.g water-methanol standard
Record the water content displayed by the instrument. The quantitative repeatability is expressed as the relative standard deviation RSD of the water content measurement results and calculated according to formula (3):
Where: RSD
Relative standard deviation, %
Number of measurements;
Number of measurement values:
Arithmetic mean of the number of measurements
Injection number
6.3.5 Verification of electrolysis speed
After 1000
is the measurement time. When verifying
Start the titration of the sample with a stopwatch and stop the timer at the end of the titration. 6.3.6 Verification of zero balance time
After the instrument is balanced three times with empty electrolysis, record the time taken by the instrument for empty electrolysis, which is the zero balance time. 6.4 Handling of verification results
METROL
Instruments that pass the verification according to this regulation shall be issued with a verification certificate (the format of the inner page of the verification certificate is shown in Appendix C), and instruments that fail the verification shall be issued with a verification result notice (the format of the inner page of the verification result notice is shown in Appendix D). 6.5 Verification cycle
The verification cycle shall generally not exceed 1 year. If the instrument has been repaired or there is any doubt about the measurement result, it can be verified at any time.
Appendix A
JJG1844—2008
Calibration of micro-syringes
The micro-syringes shall have good airtightness and shall be cleaned and dried before calibration. The mercury used for calibration shall be clean. Calibration method: At room temperature, extract a certain volume of mercury and plug the needle with a silicone rubber pad. Weigh it on an analytical balance of one hundred thousandth of a gram. Then, the mercury is beaten out and weighed again… times. The mass of the mercury can be obtained by subtraction, and then the volume is calculated as follows.
Where: V is the actual volume, ml
the mass of the first weighing, g
V=M,-M2
p water tongs
the mass pan of the second weighing, g;
p ice silver-the density of mercury at room temperature, g/mL. Each volume point is calibrated 6 times: the arithmetic mean is taken. Its relative standard deviation should be within 1%. 6
Appendix B
Inspection unit
Instrument name
Instrument model
Standard name
Measurement range
Verification period
Verifier
Appearance:
Indication error (μg)
Verification point
JJG 1044—2008
Original calibration record of Micro-View Moisture Meter
Address of the testing unit
Manufacturer
Factory abbreviation
Standard substance
Standard value
(W,—W,)
Certificate number of standard instrument
Valid until
Valid until
Verifier
Measured value
Indication error
(Average value）
Repeatability of indication
Electrolysis speed:
Measured value/ug
Zero balance time:
Insulation resistance:
Insulation strength:
Leakage current:
JJG1044—2008
Average value/μg
Relative standard deviation
METROL
Appendix C
Verification environmental conditions:
Verification items
10 μg
Indication error
5000pg
Repeatability (RSD)
Electrolysis speed
Zero balance time
Insulation resistance
Dielectric strength
Leakage current
JJG 1044—2008
Inner page format of verification certificate
Verification results
Technical requirements
Complete markings, functions are in good condition, no damage that affects normal operation
+(5% verification point+3)μg
50 Hz, 1 500 V. Current limit 5 mA, 1 min without breakdown and arcing
Verification results4 Power on and 52
Manual inspection.
6.3.2.2 Verification of insulation resistance
Apply a 500V DC test voltage between the power cord and the housing. After stabilization for 5s, measure the pure insulation resistance
6.3.2.3 Verification of insulation strength
Use a voltage test device to apply a test voltage of 500V between the power cord and the ground terminal, limit the current to 5mA, and maintain it for 1min. Observe whether there is arcing and breakdown, and then steadily drop to zero. 6.3.2.4 Verification of leakage current
Connect a leakage current tester between the power cord and the housing, and unadjust the voltage to 242V. Measure once, then change the power polarity twice, repeat the measurement once, and take the maximum value of the two times, which is the leakage current of the instrument. 6.3.3 Indication error verification
In the range of (10～5000)μg, select 10, 100, 1000, 5000μg or so for verification. To reduce the measurement error, different standard substances and micro-injectors are used for different verification points (as shown in Table 2). When measuring, first use the required micro-injector to extract the standard substance (or distilled water) to the required scale, weigh the mass W of the injection needle on the analytical balance, and then inject the sample. The injection needle must enter below the electrolyte level, and pull it out after all the sample is injected. Wipe off the electrolyte on the outside of the injection needle, weigh the mass W of the injector, and repeat the measurement 3 times for standard substances with different water contents. The average value of the difference between the measured value and the standard value at the verification point is the instrument indication error. 4
Water content calibration point
(10~-1000)μg
JJG1044-2008
Table 2 Different calibration points use different standard materials and micro-injectors Standard materials
1mg/g water methanol
(1.000~5000)pg
The indication error is calculated according to formula (2):
In the formula: Az
Distilled water
Measurement value of the calibration point, ug;
Standard value of the calibration point g
Measurement repeatability calibration
Use micro-injector
10L, 100uL, 1ml
When the instrument is stable, use 10L micro-injector to inject 10 concentration hostage. Continuous injection 6 times!
.g water-methanol standard
Record the water content displayed by the instrument. The quantitative repeatability is expressed as the relative standard deviation RSD of the water content measurement results and calculated according to formula (3):
Where: RSD
Relative standard deviation, %
Number of measurements;
Number of measurement values:
Arithmetic mean of the number of measurements
Injection number
6.3.5 Verification of electrolysis speed
After 1000
is the measurement time. When verifying
Start the titration of the sample with a stopwatch and stop the timer at the end of the titration. 6.3.6 Verification of zero balance time
After the instrument is balanced three times with empty electrolysis, record the time taken by the instrument for empty electrolysis, which is the zero balance time. 6.4 Handling of verification results
METROL
Instruments that pass the verification according to this regulation shall be issued with a verification certificate (the format of the inner page of the verification certificate is shown in Appendix C), and instruments that fail the verification shall be issued with a verification result notice (the format of the inner page of the verification result notice is shown in Appendix D). 6.5 Verification cycle
The verification cycle shall generally not exceed 1 year. If the instrument has been repaired or there is any doubt about the measurement result, it can be verified at any time.
Appendix A
JJG1844—2008
Calibration of micro-syringes
The micro-syringes shall have good airtightness and shall be cleaned and dried before calibration. The mercury used for calibration shall be clean. Calibration method: At room temperature, extract a certain volume of mercury and plug the needle with a silicone rubber pad. Weigh it on an analytical balance of one hundred thousandth of a gram. Then, the mercury is beaten out and weighed again… times. The mass of the mercury can be obtained by subtraction, and then the volume is calculated as follows.
Where: V is the actual volume, ml
the mass of the first weighing, g
V=M,-M2
p water tongs
the mass pan of the second weighing, g;
p ice silver-the density of mercury at room temperature, g/mL. Each volume point is calibrated 6 times: the arithmetic mean is taken. Its relative standard deviation should be within 1%. 6
Appendix B
Inspection unit
Instrument name
Instrument model
Standard name
Measurement range
Verification period
Verifier
Appearance:
Indication error (μg)
Verification point
JJG 1044—2008
Original calibration record of Micro-View Moisture Meter
Address of the testing unit
Manufacturer
Factory abbreviation
Standard substance
Standard value
(W,—W,)
Certificate number of standard instrument
Valid until
Valid until
Verifier
Measured value
Indication error
(Average value）
Repeatability of indication
Electrolysis speed:wwW.bzxz.Net
Measured value/ug
Zero balance time:
Insulation resistance:
Insulation strength:
Leakage current:
JJG1044—2008
Average value/μg
Relative standard deviation
METROL
Appendix C
Verification environmental conditions:
Verification items
10 μg
Indication error
5000pg
Repeatability (RSD)
Electrolysis speed
Zero balance time
Insulation resistance
Dielectric strength
Leakage current
JJG 1044—2008
Inner page format of verification certificate
Verification results
Technical requirements
Complete markings, functions are in good condition, no damage that affects normal operation
+(5% verification point+3)μg
50 Hz, 1 500 V. Current limit 5 mA, 1 min without breakdown and arcing
Verification resultsg of water-methanol standard
Record the water content displayed by the instrument. The quantitative repeatability is expressed as the relative standard deviation RSD of the water content measurement results and calculated according to formula (3):
Where: RSD
Relative standard deviation, %
Number of measurements;
Number of measurement values:
Arithmetic mean of the number of measurements
Injection number
6.3.5 Verification of electrolysis speed
After 1000
is the measurement time. When verifying
Start the titration of the sample with a stopwatch and stop the timer at the end of the titration. 6.3.6 Verification of zero balance time
After the instrument is balanced three times with empty electrolysis, record the time taken by the instrument for empty electrolysis, which is the zero balance time. 6.4 Handling of verification results
METROL
Instruments that pass the verification according to this regulation shall be issued with a verification certificate (the format of the inner page of the verification certificate is shown in Appendix C), and instruments that fail the verification shall be issued with a verification result notice (the format of the inner page of the verification result notice is shown in Appendix D). 6.5 Verification cycle
The verification cycle shall generally not exceed 1 year. If the instrument has been repaired or there is any doubt about the measurement result, it can be verified at any time.
Appendix A
JJG1844—2008
Calibration of micro-syringes
The micro-syringes shall have good airtightness and shall be cleaned and dried before calibration. The mercury used for calibration shall be clean. Calibration method: At room temperature, extract a certain volume of mercury and plug the needle with a silicone rubber pad. Weigh it on an analytical balance of one hundred thousandth of a gram. Then, the mercury is beaten out and weighed again… times. The mass of the mercury can be obtained by subtraction, and then the volume is calculated as follows.
Where: V is the actual volume, ml
the mass of the first weighing, g
V=M,-M2
p water tongs
the mass pan of the second weighing, g;
p ice silver-the density of mercury at room temperature, g/mL. Each volume point is calibrated 6 times: the arithmetic mean is taken. Its relative standard deviation should be within 1%. 6
Appendix B
Inspection unit
Instrument name
Instrument model
Standard name
Measurement range
Verification period
Verifier
Appearance:
Indication error (μg)
Verification point
JJG 1044—2008
Original calibration record of Micro-View Moisture Meter
Address of the testing unit
Manufacturer
Factory abbreviation
Standard substance
Standard value
(W,—W,)
Certificate number of standard instrument
Valid until
Valid until
Verifier
Measured value
Indication error
(Average value）
Repeatability of indication
Electrolysis speed:
Measured value/ug
Zero balance time:
Insulation resistance:
Insulation strength:
Leakage current:
JJG1044—2008
Average value/μg
Relative standard deviation
METROL
Appendix C
Verification environmental conditions:
Verification items
10 μg
Indication error
5000pg
Repeatability (RSD)
Electrolysis speed
Zero balance time
Insulation resistance
Dielectric strength
Leakage current
JJG 1044—2008
Inner page format of verification certificate
Verification results
Technical requirements
Complete markings, functions are in good condition, no damage that affects normal operation
+(5% verification point+3)μg
50 Hz, 1 500 V. Current limit 5 mA, 1 min without breakdown and arcing
Verification resultsg of water-methanol standard
Record the water content displayed by the instrument. The quantitative repeatability is expressed as the relative standard deviation RSD of the water content measurement results and calculated according to formula (3):
Where: RSD
Relative standard deviation, %
Number of measurements;
Number of measurement values:
Arithmetic mean of the number of measurements
Injection number
6.3.5 Verification of electrolysis speed
After 1000
is the measurement time. When verifying
Start the titration of the sample with a stopwatch and stop the timer at the end of the titration. 6.3.6 Verification of zero balance time
After the instrument is balanced three times with empty electrolysis, record the time taken by the instrument for empty electrolysis, which is the zero balance time. 6.4 Handling of verification results
METROL
Instruments that pass the verification according to this regulation shall be issued with a verification certificate (the format of the inner page of the verification certificate is shown in Appendix C), and instruments that fail the verification shall be issued with a verification result notice (the format of the inner page of the verification result notice is shown in Appendix D). 6.5 Verification cycle
The verification cycle shall generally not exceed 1 year. If the instrument has been repaired or there is any doubt about the measurement result, it can be verified at any time.
Appendix A
JJG1844—2008
Calibration of micro-syringes
The micro-syringes shall have good airtightness and shall be cleaned and dried before calibration. The mercury used for calibration shall be clean. Calibration method: At room temperature, extract a certain volume of mercury and plug the needle with a silicone rubber pad. Weigh it on an analytical balance of one hundred thousandth of a gram. Then, the mercury is beaten out and weighed again… times. The mass of the mercury can be obtained by subtraction, and then the volume is calculated as follows.
Where: V is the actual volume, ml
the mass of the first weighing, g
V=M,-M2
p water tongs
the mass pan of the second weighing, g;
p ice silver-the density of mercury at room temperature, g/mL. Each volume point is calibrated 6 times: the arithmetic mean is taken. Its relative standard deviation should be within 1%. 6
Appendix B
Inspection unit
Instrument name
Instrument model
Standard name
Measurement range
Verification period
Verifier
Appearance:
Indication error (μg)
Verification point
JJG 1044—2008
Original calibration record of Micro-View Moisture Meter
Address of the testing unit
Manufacturer
Factory abbreviation
Standard substance
Standard value
(W,—W,)
Certificate number of standard instrument
Valid until
Valid until
Verifier
Measured value
Indication error
(Average value）
Repeatability of indication
Electrolysis speed:
Measured value/ug
Zero balance time:
Insulation resistance:
Insulation strength:
Leakage current:
JJG1044—2008
Average value/μg
Relative standard deviation
METROL
Appendix C
Verification environmental conditions:
Verification items
10 μg
Indication error
5000pg
Repeatability (RSD)
Electrolysis speed
Zero balance time
Insulation resistance
Dielectric strength
Leakage current
JJG 1044—2008
Inner page format of verification certificate
Verification results
Technical requirements
Complete markings, functions are in good condition, no damage that affects normal operation
+(5% verification point+3)μg
50 Hz, 1 500 V. Current limit 5 mA, 1 min without breakdown and arcing
Verification results
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