Some standard content:
National Metrology Verification Regulation of the People's Republic of China JJG:205--2005
Mechanical Thermo - hygrometers
Mechanical Thermo - hygrometers2005-09-05 Issued
Implementation on 2006-03-05
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China IFG205-24H05
Verification Regulation of
Mechanical Thermo - hygrometersJJG205-2005
Replaces JJG 205-1980
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on September 5, 2005, and came into effect on March 5, 2006.
Responsible unit: National Physical and Chemical Metrology Technical Committee Drafting unit: Shanghai Metrology and Testing Technology Research Institute This regulation is entrusted to the Physical and Chemical Metrology Technical Committee for interpretation. Main drafters of this regulation:
Zhang Wendong
Participating drafters:
Wang Guoyan
Zhang Lifang
JJ205—2005
([Shanghai Metrology and Testing Technology Research Institute]) (1Shanghai Metrology and Testing Technology Research Institute)||tt ||(Shanghai Institute of Measurement and Testing Technology) 1
References
3 Terms
3.1 Mechanical hygrometer
Wet meter
Mechanical thermometer and hygrometer
4 Overview
Measuring performance requirements
Temperature indication error
Humidity indication error
Temperature hysteresis/hysteresis error
Gross complex
6 General technical requirements
JJG 205-2005
Other requirements for pointer-type thermometers and psychrometers 6.2
6.3 Other requirements for recording thermometers and hygrometers
7 Control of measuring instruments
Verification conditions
Verification items
Verification methods
Handling of verification results
7.5 Verification period
Appendix A
Appendix B
Appendix C
Appendix DbZxz.net
Verification record format
Verification certificate format
Verification result notification format
Test method for uniformity and passivity of temperature and humidity in temperature verification cabinet (1)
1 Scope
JJG 205-2005
Verification Procedure for Mechanical Thermometers and Hygrometers
This procedure applies to the initial verification, subsequent verification and in-use inspection of mechanical thermometers and hygrometers and mechanical condensation meters (hereinafter referred to as thermometers and hygrometers) with a measuring range of 5%~～50C and 30%RH~95%RH: 2 References
Humidity Measurement", Meteorological Press, 1990 1st edition JJG2046:199) "Metrological Verification System for Humidity Measuring Instruments" J1S B7920:2000 "Test Method for Hygrometer" JB/T68621993 Thermohygrometer
When using this procedure, attention should be paid to the use of the current valid versions of the above-mentioned references. 3 Terminology
3.1 Mechanical hygrometer
A pointer-type and recording hygrometer that uses hair, nylon and organic polymer coating materials as humidity sensing elements and can directly indicate relative humidity. It includes hair hygrometers, hair humidity recorders, etc. 3.2 Psychrometer
A natural ventilation dry-bulb hygrometer consisting of a glass liquid thermometer, a water jacket on the wet bulb, a water dew and humidity calculation table and a slide rule.
3.3 Mechanical hygrometer
An integrated temperature and humidity dual-purpose instrument consisting of a temperature part (mechanical hygrometer or decimeter) and a temperature part (bimetallic thermometer or glass thermometer). 4 Overview
The geometrical dimensions of organic polymer materials such as hair, nylon and polyimide will change with the change of relative viscosity. Mechanical thermometers take advantage of this property and make the above materials into linear or strip-shaped humidity-sensing elements or coatings on elastic materials to form hairspring-like humidity-sensing elements. Then, through a mechanical amplification device, the geometrical changes caused by humidity changes are indicated by a pointer or recorded by a recording pen, thereby directly indicating the relative humidity. Under certain conditions, the relative condensation temperature and wet bulb humidity of the air show a certain functional relationship, that is, the lower the humidity, the lower the wet bulb temperature, and the greater the temperature difference between the wet bulb and the dry and wet bulb. The psychrometer is made based on this principle. The mechanical temperature and humidity instrument is a two-piece temperature and humidity instrument consisting of a temperature part and a humidity part. The temperature part is a metal thermometer or a glass liquid thermometer, and the humidity part is a mechanical hygrometer or a psychrometer. It is suitable for measuring the temperature and humidity of indoor environments such as laboratories, computer rooms, warehouses, and large rooms. 1
5 Measurement performance requirements
5.! Temperature indication error
JJG205—2005
The temperature evaluation error of the temperature measurement shall not exceed: +2.0%. 5.2 Relative limit indication error
The relative limit indication error of the thermohygrometer shall not exceed: a) ±5%RH (40%RH ~ 7%RH, 20 ): b) ±7%RH (below 40%RH or above 7%RH, 20 ) 5.3 Temperature hysteresis/humidity error
5.3.1 The temperature error of the thermohygrometer shall not exceed 0.5 5.3.2 The hysteresis error of the thermohygrometer shall not exceed 3%RH. 5.4 Repeatability
5.4.1 Temperature repeatability: ≤0.5 .
5.4.2 Humidity repeatability: 2%RH.
General technical requirements
6.1 Appearance
61 The appearance and structure of the thermohygrometer shall be good, without obvious mechanical damage, and shall be free of scratches and rust: The requirements for the thermohygrometer in use can be relaxed, and there shall be no appearance defects that affect the metering performance of the instrument. 6.1.2 The name of the manufacturer (or factory mark), model, factory number and the manufacturing license mark and number of the measuring instrument shall be marked on the hygrometer.
6.2 Other requirements for pointer-type thermometers and condensation meters 6.2.1 The scale plate shall be positioned correctly and not skewed, and the scale lines shall be clear and uniform. 6.2.2 The humidity scale range shall not be less than 30%RH~95%RH, the minimum scale shall not be greater than +2%RH, and it shall be possible to read to 1%RH. Each 10%RH or 20%RH scale line shall be marked with a corresponding number, and the scale line length shall be the longest. 6.2.3 The temperature scale range shall not be less than 10℃~40℃, the minimum scale shall not be greater than 1℃, and it shall be possible to read to 0.5℃. Each 10 scale line shall be marked with a corresponding number, and the scale line length shall be the longest. 6.2.4 The pointer shall be straight, can be flexibly rotated, and reset automatically. 6.2.5 The liquid column of the glass liquid thermometer shall be clearly displayed without bubbles or broken columns. 6.2.6 All parts of the mixing meter should be complete and the upper water jacket should be clean. 6.3 Other requirements for recording temperature and filtration meters
6.3.1 Temperature and humidity recording range: humidity not less than 30%RH~95%RH, temperature not less than 10~40%℃. 6.3.2 The minimum humidity scale should not be greater than 2%RH, and it can be guaranteed to be readable to 1%RII. The minimum temperature division value is not greater than 1%, and it can be guaranteed to be readable to 0.5%. 6.3.3 The pen tip can draw lines smoothly, without scratching the paper or breaking the line. The width of the line does not exceed 0.3mm. 6.3.4 The recorder can work normally, the pen stop can move smoothly, and the pen tip can be moved away from the recording paper and the pen tip can be close to the recording paper: 63.5 The maximum deviation between the record pen line and the recording paper line should meet the following requirements: for oral recording type, it should not exceed 1/3 of the time scale spacing 2, and for weekly recording type, it should not exceed 1/4 of the time scale spacing. Control of measuring instruments Control of measuring instruments includes: initial calibration, subsequent calibration and in-use inspection. 7.1 Calibration conditions 7.1.1 Calibration instruments and equipment 7.1.1.1 Standard Instruments
The standard instrument for the filter and atomizer can be selected from the following two types of equipment: 1. Precision dew point meter
Precision dew point meter with platinum resistance thermometer should be selected, which can display dew point, relative humidity and temperature at the same time. Its technical indicators should meet the requirements of Table 1.
Table 1 Precision dew point meter
b) Ventilation hygrometer
Display range
5 ~ 50
0 CDP - 40 DP
Maximum allowable error
Electric digital ventilation hygrometer should be selected, which can display relative humidity and temperature at the same time. Its technical indicators should meet the requirements of Table 2. Ventilation hygrometer should be used in conjunction with atmospheric pressure gauge. Table 2 Ventilation and humidity table
Process and humidity
Supporting equipment
a) Temperature and humidity calibration box
Range
5 50 r
40%KH~70%RH (at 20℃)
Greater than 70%RH (at 20 t)
Maximum allowable error
The temperature and humidity calibration box must have automatic temperature and filter adjustment functions, the effective volume of the box should not be less than 40L, and it should be equipped with an opening door and a large transparent observation window, and its technical indicators should meet the requirements of Table 3. In addition, when the calibration object is dry and wet clothes, the wind speed in the box should not be greater than 0.2m/s. b) Atmospheric pressure gauge
Used for measuring atmospheric pressure in laboratory environment, its minimum permissible error shall not exceed ±200) Thermohygrometer
Used for measuring temperature and humidity in laboratory environment, its maximum permissible error shall meet the following requirements: temperature ±2℃, relative humidity ±5%RH.
7.1.2 Environmental conditions
Temperature range
Humidity range
Temperature uniformity
Temperature fluctuation
Humidity uniformity
Humidity fluctuation
JJG 205--2005
Table 3 Temperature and humidity calibration box
Note: The measures for adjusting the temperature and humidity uniformity and fluctuation are given in Appendix D. 7.1.2.1
Technical indicators
5 ℃ - 50 ℃
40%RH-90%RII (at 20℃)
1.0%RH (at 20℃)
±0.8%RII (at 20℃)
Temperature: 15% =25℃, temperature fluctuation should not exceed ±3/6h; Relative humidity: ≤75% RIr7.1.2.2 The working environment of the standard instrument and other supporting equipment should meet the corresponding specified conditions. 7.2 Verification items
The verification items of temperature are shown in Table 4.
Table 4 List of verification items
Verification items
General technical requirements
Indication error
Temperature recovery/humidity error
Recoverability
First verification
Note: “→” indicates items that should be checked, and “一” indicates items that may not be checked. 7.3 Verification method
7.3.1 General technical requirements
Subsequent verification
In-use inspection
The thermometer shall comply with the provisions of 6.1, 6.2 and 6.3 of this Regulation by visual inspection and manual inspection. If the inspection fails, the verification shall be stopped and the instrument shall be deemed unqualified. Subsequent verification and in-use inspection allow the instrument to have appearance defects that do not affect the metrological performance.
7.3.2 Indication error test
7.3.2.1 Preparation
Place the control head of the standard instrument in the center of the temperature and humidity calibration chamber, and place the instrument to be tested in the effective space of the temperature and humidity calibration chamber. The placement method and quantity should not affect the air circulation in the chamber. The chamber of the calibration chamber should ensure airtightness, and no damp or highly hygroscopic materials should be placed. 7.3.2.2 Temperature indication error test
The temperature test points are: 15, 20, 30 4°C. After the temperature of the calibration chamber reaches the set value, it should be stabilized for 30 minutes before reading. Read the standard instrument first, then read the instrument to be tested. Repeat the reading once after an interval of 5 minutes. Take the average value of the two readings as the temperature indication error (T, and T) of the standard instrument and the instrument to be tested! △T=TT-, where d is the temperature correction value of the standard pusher, 4
JJG 205—2005
The temperature indication error of the instrument under test at the calibration point shall comply with the provisions of 51 of this regulation. 7.3.2.3 Humidity indication error calibration
The calibration is carried out in the order from low humidity to high humidity, and the calibration points are: 40%RH, 60%RH, 80%RH. During humidity calibration, the temperature in the box is set at 20℃: When the temperature of the calibration box reaches the set value, it should be stabilized for another 30 minutes before reading, first read the standard instrument, then read the instrument under test, and repeat the reading once after 5 minutes: take the arithmetic average of the two readings as the relative humidity indication of the standard instrument and the instrument under test (H. and H). The humidity indication of the psychrometer is obtained by the 1-bulb overflow reading and the wet-bulb temperature reading through the corresponding calculation table or slide rule: the indication error is:
AH= H- H..
The humidity indication error of the instrument under test at each calibration point shall comply with the provisions of 5.2 of this regulation: 7.3.2.4 Other instructions
Temperature and humidity calibration can be carried out at the same time. The readings of the instrument under test are all carried out visually. For the D-type instrument, the line of sight should be perpendicular to the dial; for the recorder, the recording position on the recording paper should be used as the guide. 3.3 Temperature hysteresis and hysteresis error calibration
7.3.3.1 Temperature hysteresis error calibration
Carry out temperature indication error calibration in the order of 10, 20, 30, 40, 30, 20, 10℃. The difference between the temperature indication error of the forward and reverse strokes at the calibration point, i.e., the temperature hysteresis, shall meet the requirements of 5.3.1. 7.3.3.2 Hysteresis error calibration
At 20:, carry out filtration indication error calibration in the order of 40%RH, 60%RH, 80%RH, 60%RH, 40%RH. The difference between the humidity indication error of the forward and reverse strokes at the same calibration point, i.e., the hysteresis error, shall meet the requirements of 5.3.2.
7.3.4 Repeatability verification
7.3.4.1 Temperature repeatability verification
Carry out indication error verification in the order of 10, 20, 30 and 40℃, and repeat it three times in succession. Calculate the maximum difference between the indication errors of three calibrations at each calibration point, i.e., temperature repeatability. It shall comply with the provisions of 5.4.1 of this Regulation. 7.3.4.2 Humidity repeatability calibration Carry out indication error calibration in the order of 40%RH, 60%RII, and 801II, and conduct three consecutive reviews. Calculate the maximum difference between the indication errors of three calibrations at each calibration point, i.e., temperature repeatability. It shall comply with the provisions of 5.4.2 of this Regulation. 7.3.4.2 Humidity repeatability calibration Carry out indication error calibration in the order of 40%RH, 60%RII, and 801II, and conduct three consecutive reviews. Calculate the maximum difference between the indication errors of three calibrations at each calibration point, i.e., temperature repeatability. It shall comply with the provisions of 5.4.2 of this Regulation. 7.3.4.2 Humidity repeatability calibration Carry out indication error calibration in the order of 40%RH, 60%RII, and 801II, and conduct three consecutive reviews. Calculate the maximum difference between the indication errors of three calibrations at each calibration point, i.e., temperature repeatability. It shall comply with the provisions of 5.4.2 of this Regulation. The inner pages of the verification certificate or the verification failure notice shall include the verification parts, verification items, verification results/verification data, measurement uncertainty and inclusion factors, etc. The inner page format is shown in Appendix B and Appendix C. 7.5 Verification cycle
The verification cycle of mechanical thermometers is generally no more than 1 year. If they are repaired or the indication value is adjusted during use, they must be re-calibrated.
Appendix A
Inspection unit:
Instrument name:
Accuracy:
Manufacturer/merchant:
Technical report and code:
Standard instrument and supporting equipment:
Temperature ℃
Humidity/%RH
Atmospheric pressure/hPa
Appearance:
Indication:
Standard instrument
Temperature indication error:
Expanded uncertainty of temperature indication error: (h=
Verifier:
JJG 205 -- 2005
Verification record format
Original record number:
Model/specification:
Instrument number:
Verification location:
Verification environmental conditions
At the beginning of verification
At the end of verification
Lumen (20 o'clock)
Relative humidity indication error:
Actual relative
Relative humidity
Reading of the instrument under test
Tidal bulb temperature
Expanded uncertainty of relative humidity indication error: U
【Verifier:
Verification period:
Relative humidity
Appendix B
Verification certificate number:
Verification basis (on behalf of the expert):
JJG 205—-2005
Inner page format of verification certificate
Name, code, certificate number and validity period, accuracy and measuring range of standard instrument or standard pusher Expanded uncertainty of this verification result: (including factors): Verification location and environmental conditions:
Verification results
1) Appearance:
2) Indication error:
Note:
Actual value
Reading of the instrument under test
Indication error
Actual value
Humidifier RH (20 o'clock)
Reading of the instrument under test
Indication error
Appendix C
Verification result certificate number:
Verification basis (code):
J.JG 205—2(M15
Inner page format of the verification result notification
Name, serial number, certificate number and validity period of the standard instrument or standard device, accuracy and measurement range The accumulated expanded uncertainty of this verification (including factors): Verification location and environmental conditions:
Verification results:
1) Appearance:
2) Indication:
The instrument
Remarks:
Actual value
Reading of the controlled instrument
Indication error
Actual value
Does not meet the requirements of the regulations and is judged to be unqualified. Humidity/%RH (20 o'clock)
Reading of the tested instrument
Indication error
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