Some standard content:
Aquatic Industry Standard of the People's Republic of China
SC/T7006--2001
Dissolved oxygen meter
Published on September 27, 2001
Published by the Ministry of Agriculture of the People's Republic of China
Implemented on November 1, 2001
SC/T7006-2001
This standard is a revision of S0T7006-1988 (formerly GB/T8587-1988) dissolved oxygen meter. Compared with the original standard, the revised content is:
-Product classification regulations are changed to technical requirements! The requirements for withstand voltage performance are deleted
The product mainly adopts the form of DC power supply, and the requirements for the insulation performance of AC power supply are deleted:-The instrument matching is not a technical requirement,
Only the requirements for ambient temperature are stipulated for the working environment conditions. This standard replaces SC/T70061988 from the date of implementation. Appendix A of this standard is the appendix of the standard. This standard was proposed by the Fisheries Bureau of the Ministry of Agriculture.
This standard is under the jurisdiction of the Fishery Machinery and Instrument Research Institute of the Chinese Academy of Fishery Sciences. The drafting unit of this standard is the Fishery Machinery and Instrument Research Institute of the Chinese Academy of Fishery Sciences. The main drafters of this standard are Ye Bingdong, Shi Xiaotian, and Wang Wei. This standard was first issued in January 1988 and revised for the first time in November 2001. 1. Scope
Aquatic Industry Standard of the People's Republic of China
Dissolved oxygen meter
Dissolved oxygen meter
SC/T 7006--2001
Replaces SC/T7006-1988
This standard specifies the application technical requirements, test methods and inspection rules for dissolved oxygen meters using membrane electrodes as sensors. This standard applies to membrane-type sensor dissolved oxygen meters. 2 Reference Standards
The clauses contained in the following standards constitute the clauses of this standard by citing them in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB191-2000 Pictorial marking for packaging, storage and transportation
GB/T7489-1987 Water quality - Determination of dissolved oxygen (eqVISO58131983) 3 Definitions
This standard adopts the following definitions.
3.1 Sensor residual current
The current output by the sensor when it is placed in ammonia-free water. 3.2 Zero value error
When the ammonia being measured is at a low value, the value of the quench oxygen meter position deviation caused by the residual current of the sensor. 3.3 Response time
When measuring, the time required for the dissolved oxygen indication of the dissolved oxygen meter to change to 90% of the actual measured value. 3.4 Repeatability of oxygen measurement
When the dissolved oxygen content is measured multiple times under the same measurement conditions, the consistency between the measurement results is expressed by the standard deviation of multiple measurements.
3.5 Oxygen stability
Under the specified working conditions, the drift degree of the dissolved oxygen indication is measured continuously. 4 Technical requirements
4.1 Appearance quality
The housing and rotating parts of the dissolved oxygen meter should be intact. The plating (coating) layer should be uniform, without peeling, rust and blistering. 4.2 Measurement range and graduation value
The dissolved oxygen meter should preferably use the following ranges: 0~5, 0~10, 0~~20 two ranges, the unit is mg/1-. The minimum graduation value should not be less than 0. 1 mg/L. 4.3 When the water temperature is 20℃, the response time shall exceed 60s.4.4 The zero value error shall not exceed 0.15ng/1.
Approved by the Ministry of Agriculture of the People's Republic of China on 2001-09-27 and implemented on 2001-11-01
4.5 The temperature measurement error shall not exceed ±1℃.
SC/T 7006—2001
4.6 When the water temperature and temperature difference are within ±10℃, the measurement error of dissolved oxygen shall not exceed ±0.5mg/L. 4.7 The repeatability of oxygen measurement shall not exceed 0.2mg/L. 4.8 The stability of oxygen measurement shall not exceed ±0.2mg/L. 4.9 Instruments with system power supply: There shall be a charging indication. 4.10 When the ambient temperature is 0℃~40℃: The dissolved oxygen meter shall be able to work normally. 5 Test method
5.1 Test conditions
5. 1. 1 Ambient temperature: 20℃±5℃. 5.1.2 Relative humidity: not more than 85%.
5. 1.3 Atmospheric pressure: 86 Pa~~106 kPa. 5.1.4 Test water. Distilled water.
5.1.5 Surrounding environment, no strong magnetic field, electric spark interference. 5.1.6 Standard value of dissolved oxygen in water sample Take three bottles of the same water sample and titrate them with GB/T7489 iodine titration method. Each bottle is titrated twice. The relative error of the two titrations is not more than 0.1mg/L to be valid. Take the average of the oxygen falling amount of the three bottles of water samples as the standard value of dissolved oxygen in the water sample. 5.2 Test equipment
5.2. 1 Use the chemical reagents and glassware required for the GB/T 7489 iodine titration method to measure dissolved oxygen. 5.2.2 Three thermostatic water baths (tanks) with a temperature control accuracy of 0.2°C and an external circulation cooling device. 5.2.3 High-pressure gas cylinders filled with oxygen and nitrogen and equipped with low-pressure pressure reducing valves. 5.2.4 Air pump.
5.2. Three second-class standard mercury thermometers with a graduation value of 0.1°C from 50°C to 50°C. 5.2.6 Analytical thermometer (accuracy not less than 0.020). 5.2.7 Stopwatch (accuracy not less than 0.5 s/d)5.3 Test preparation
5.3.1 Preparation of oxygen-free water
5% iodine (Na2SO4) solution is oxygen-free water. When preparing it, an appropriate amount of cobalt chloride (CoCl2) can be used as a catalyst. 5.3.2 Preparation of saturated dissolved oxygen water
Keep the water temperature of the constant temperature water bath constant at the desired temperature value, and then use an air pump to continuously inflate the water for more than 2 hours. 5.3.3 Calibration of dissolved oxygen meter
Before calibration, the DC power supply should be checked. If it is in an undervoltage state, a new battery should be replaced first. 5.3.3.1 Zero adjustment: Perform in accordance with the product manual. 5.3.3.2 Calibration According to the water temperature during the test and Appendix A of this standard, place the sensor of the dissolved oxygen meter in the saturated dissolved oxygen water towel, and adjust the indication of the dissolved oxygen meter to the saturated dissolved oxygen value corresponding to the water temperature; or calibrate according to the method specified in the product manual. When measuring, if the actual atmospheric pressure deviates from the standard atmospheric pressure, it should be corrected according to formula (1). A,= A× 101.3
Where: A-saturated dissolved load value at atmospheric pressure, g/L; A-oxygen free value at nominal atmospheric pressure (101.3kPa), mg/Lp-actual atmospheric pressure during measurement, kPa. 5.4 Appearance quality inspection
Appearance quality is inspected by visual inspection.
5.5 Test of zero value error and response time
SC/T 7006—2001
Put the sensor of the calibrated dissolved oxygen meter in oxygen-free water at a temperature of 20℃±5℃, and count to the end of 5 minutes. The indication of the dissolved oxygen meter is the zero value error of oxygen measurement. Then move the sensor into saturated dissolved oxygen water at a temperature of 20±1℃. The time required for the dissolved oxygen indication of the dissolved oxygen meter to rise to 90% of the saturated dissolved oxygen value is the response time. 5.6 Test of measurement error
5.6.1 Test of temperature measurement error
Put the sensor and standard thermometer of the calibrated dissolved oxygen meter in three constant temperature water baths () at the same time, adjust the water temperature to about 10℃, 20℃, and 30℃ respectively, and measure the difference between the temperature indication of the dissolved oxygen meter and the reading of the standard thermometer in the same water (pressure), which is the temperature measurement error.
5.6.2 Test of oxygen measurement error
The water temperature of the three constant temperature water baths (slots) is stabilized at 10℃, 20℃, and 30℃ respectively. For the 10℃ and 30℃ water samples, make them saturated with dissolved oxygen. For the 20℃ water samples, nitrogen and oxygen are passed to stabilize the dissolved oxygen in the water at about 3mg/L. Then use the dissolved oxygen meter to measure the water samples of the above three water temperatures respectively, and each measurement time is 5min. When taking water samples, take three bottles for each drink and do iodine titration. The average value is used as the standard value of dissolved oxygen. The difference between the measured value and the standard value is the measurement error. 5.7 Oxygen measurement repeatability test
The water temperature in the warm water bath (tank) is stabilized at 20°C, and the water sample is saturated with dissolved oxygen. Then use a dissolved oxygen meter to measure the water sample six times (5 min each time) at even intervals within 1 hour, record the six values of the dissolved oxygen meter, and calculate the standard deviation according to formula (2), which is the oxygen measurement repeatability.
In the formula; S~mn oxygen measurement repeatability obtained by water measurement, tmg /L; r; the i-th measurement value,mg/L;
2—the average value of n measurements, mg/L; n—the number of measurements.
5.8 Stability test
Control the temperature of the dissolved oxygen saturated water in the cabinet warm water bath (tank) at 20℃±0.2℃, place the sensor in the constant temperature water bath (tank), record the initial value Ai after half an hour of startup, and take water samples to measure the initial value D2 by iodine titration method: When the test is continued to the 4th hour, record the final value A2 indicated by the dissolved gas meter, and take water samples to measure the final value D2 by iodine titration method. The oxygen stability is calculated according to formula (3): Y=(AA)-(D2-DI)
Where: ~ Stability of dissolved oxygen meter, mg; A:-initial value measured by dissolved oxygen meter·mg/L; A2-final value measured by dissolved oxygen meter, mg/I.:L),-initial value measured by iodine titration method, nig/.D2-final value measured by iodine titration method, tmg/L. 5.9 Check the undervoltage indication of the DC power supply instrument. Adjust the adjustable voltage-stabilized power supply to below the undervoltage value as the self-test undervoltage measure for the instrument power supply. 5.10 Test for environmental temperature adaptability
Place the calibrated dissolved oxygen measuring instrument in a high and low temperature test chamber, and place its sensor outside the test chamber through a connecting line. Adjust the test chamber temperature to 0±0.2℃ and 40±0.2℃ respectively. After the temperature stabilizes, keep it for 2 hours. Place the sensor in the saturated dissolved oxygen water in a constant temperature water bath (trough). The instrument should be able to work normally. 6 Inspection rules
6.1 Inspection classification
a) Factory inspection;
b) Type test inspection.
6.2 Factory inspection
6.2.1 Inspection samples
SC/T 7006—2001
All products must be inspected before entering the warehouse or before delivery. 6.2.2 Inspection Items
The inspection items are the requirements specified in 4.1, 4.2, 4.3, 4.4, 4.5 and 4.9 of this standard. 6.2.3 Qualification Determination
When the test results of all inspection items meet the requirements, it is judged as qualified; otherwise, it is judged as unqualified. Unqualified products are allowed to be returned to the workshop for replacement of components and re-debugging, and can only be put into the warehouse or sold after re-inspection. 6.3 Type Inspection
6. 3. 1 Type inspection should be carried out in any of the following situations: a) Before the new product batch is put into production or the old product is transferred to the factory for production, a prototype should be produced and type inspection should be carried out: b) When there are major changes in structure, materials and processes during production; c) During normal production, once a year,
d) When production is resumed after suspension for more than one year; e) When the factory inspection results are significantly different from the last type inspection; [When the national quality and technical supervision agency proposes the requirement for type inspection. 6.3.2 Inspection criteria: The number of samples for type inspection is 2 units. 6.3.3 Inspection items: All items in Chapter 4. 6.3.4 Qualification judgment: When the test results of all inspection items meet the requirements, the type inspection is qualified; otherwise, the type inspection is unqualified. If the unqualified items are caused by the quality problems of components, it is allowed to replace the components and then conduct double inspection on the unqualified items and items related to the components. When the double inspection is qualified, the type inspection is qualified; otherwise, the type inspection is unqualified. 7 Labeling, packaging, transportation and storage
7.1 Labeling
7.1.1 Product labeling:
a) Manufacturer's name:
b) Product name;
c) Trademark;
d) Product model;
e) Production batch number or factory number.
7.1.2 The packaging labeling shall comply with the requirements of GB 191. 7.2 Packaging
7.2.1 Carton requirements:
a) Cartons must meet the requirements of packaging strength; b) After the carton is formed, the box shape is square, the four corners are firm, there is no overlapping corners, no leakage, no degumming, and the cover is neatly aligned; c) The carton should be dry.
7.2.2 Protection requirements, the heat-resistant cushioning material in the box, the host should be packed in a moisture-proof plastic bag. 7.2.3 Documents included in the package:
a) Product certificate;
b) Product manual;
c) Packing list.
7.3 Transportation
SC/T 70062001
The packaged dissolved oxygen meter should be transported on various transportation equipment such as roads, railways, waterways, and air without being directly affected by rain, wind, and strong wind.
The packaged free oxygen measuring instrument should be stored in a warehouse with an environment of -10℃ to +40℃, a relative humidity of no more than 0%, no acid or alkali gas, and no strong mechanical vibration, and should be placed on a shelf at least 0.5m above the ground and 0.3m above the wall. Temperature
SC/T7006-2001
(Appendix to the standard)
Table A1 Saturated content of oxygen in water at different temperatures and chloride concentrations (air pressure 101.3kPa) AC.
Heart. 65 3
0, G44 0
Table C. It is the solubility of oxygen in pure water, expressed in grams per liter of water, and pure water contains air with saturated water vapor (the oxygen content in the air is 20.94% (V/). When the pressure is 101.3a). 2 The solubility of oxygen in water decreases with the increase of salinity. The maximum salinity is expressed as grams of salt per liter of water. In actual use, when the maximum salinity is below 35g/L, it is a linear relationship. The △C listed in the table is the value to be subtracted from the salt concentration per gram per liter when making corrections. Therefore, the solubility of oxygen in water containing n (zone/L) of salt can be obtained by subtracting the value of nC from the corresponding solubility of pure water.1 Product marking:
a) Manufacturer's name:
b) Product name;
c) Trademark;
d) Product model;
e) Production batch number or factory number.
7. 1.2 Packaging markings shall comply with the requirements of GB 191. 7.2 Packaging
7.2.1 Carton requirements:
a Cartons shall meet the requirements of packaging strength + b) After the carton is formed, the box shape is square, the four corners are firm, there is no overlap, no leakage, no degumming, and the box cover is neatly aligned; c) The carton should be dry.
7.2.2 Protection requirements, the heat-resistant cushioning material in the box, the host should be packed in a moisture-proof plastic bag. 7.2.3 Documents included in the package:
a) Product certificate;
b) Product manual;
c) Packing list.
7.3 Transportation
SC/T 70062001
The packaged dissolved oxygen meter should be transported on various transportation equipment such as roads, railways, waterways, and airways without being directly affected by rain, wind, and strong winds.
The packaged dissolved oxygen meter should be stored in a warehouse with an environment of -10°C to +40°C, a relative humidity of no more than 0%, no acid or alkali gas, and no strong mechanical vibration, and should be placed on a shelf at least 0.5m above the ground and 0.3m above the wall. Temperature
SC/T7006—2001
(Appendix of the standard)
Table A1 Saturated content of oxygen in water at different temperatures and chloride concentrations (air pressure 101.3kPa) AC.wwW.bzxz.Net
C. G65 3
0, G44 0
Table C. is the solubility of oxygen in pure water, expressed in grams per liter of water, and pure water contains air with saturated water vapor (the oxygen content in the air is 20.94% (V/). When the pressure is 101.3a). 2 The solubility of oxygen in water decreases with the increase of salinity. The maximum salt content is expressed in grams of salt per liter of water. In actual use, when the salt content is below 35g/L, it is a linear relationship. The △C listed in the table is the value to be subtracted from the salt concentration per gram per liter when making the correction. Therefore, the solubility of oxygen in water containing n (zone/L) of salt can be obtained by subtracting the value of nC from the corresponding solubility in pure water.1 Product marking:
a) Manufacturer's name:
b) Product name;
c) Trademark;
d) Product model;
e) Production batch number or factory number.
7. 1.2 Packaging markings shall comply with the requirements of GB 191. 7.2 Packaging
7.2.1 Carton requirements:
a Cartons shall meet the requirements of packaging strength + b) After the carton is formed, the box shape is square, the four corners are firm, there is no overlap, no leakage, no degumming, and the box cover is neatly aligned; c) The carton should be dry.
7.2.2 Protection requirements, the heat-resistant cushioning material in the box, the host should be packed in a moisture-proof plastic bag. 7.2.3 Documents included in the package:
a) Product certificate;
b) Product manual;
c) Packing list.
7.3 Transportation
SC/T 70062001
The packaged dissolved oxygen meter should be transported on various transportation equipment such as roads, railways, waterways, and airways without being directly affected by rain, wind, and strong winds.
The packaged dissolved oxygen meter should be stored in a warehouse with an environment of -10°C to +40°C, a relative humidity of no more than 0%, no acid or alkali gas, and no strong mechanical vibration, and should be placed on a shelf at least 0.5m above the ground and 0.3m above the wall. Temperature
SC/T7006—2001
(Appendix of the standard)
Table A1 Saturated content of oxygen in water at different temperatures and chloride concentrations (air pressure 101.3kPa) AC.
C. G65 3
0, G44 0
Table C. is the solubility of oxygen in pure water, expressed in grams per liter of water, and pure water contains air with saturated water vapor (the oxygen content in the air is 20.94% (V/). When the pressure is 101.3a). 2 The solubility of oxygen in water decreases with the increase of salinity. The maximum salt content is expressed in grams of salt per liter of water. In actual use, when the salt content is below 35g/L, it is a linear relationship. The △C listed in the table is the value to be subtracted from the salt concentration per gram per liter when making the correction. Therefore, the solubility of oxygen in water containing n (zone/L) of salt can be obtained by subtracting the value of nC from the corresponding solubility in pure water.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.