JJF 1908-2021_English: PDF (JJF1908-2021)
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(Calibration Specification for Bimetal Thermometer)
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JJF 1908-2021
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Standard ID | JJF 1908-2021 (JJF1908-2021) | Description (Translated English) | (Calibration Specification for Bimetal Thermometer) | Sector / Industry | Metrology & Measurement Industry Standard | Word Count Estimation | 18,159 | Date of Issue | 2021-07-28 | Date of Implementation | 2022-01-28 | Older Standard (superseded by this standard) | JJG 226-2001 |
JJF 1908-2021
(Calibration Specification for Bimetal Thermometer)
National Metrology Technical Specification of the People's Republic of China
Bimetal Thermometer Calibration Specifications
Published on 2021-07-28
2022-01-28 Implementation
Released by the State Administration for Market Regulation
Bimetal Thermometer Calibration Specifications
Replacing JJG226-2001
Focal Point. National Thermometer Technical Committee
Main drafting unit. Tianjin Academy of Metrology Supervision and Testing
Beijing Institute of Metrology and Testing Sciences
Participating in the drafting unit. Xinjiang Uygur Autonomous Region Metrology and Testing Research Institute
Qingdao Metrology Technology Research Institute
Jinan Changfeng Zhiyuan Instrument Technology Co., Ltd.
Shenzhen Institute of Metrology and Quality Inspection
This specification entrusts the National Thermometry Technical Committee to be responsible for the interpretation
The main drafters of this specification.
Shen Wenjie (Tianjin Academy of Metrology, Supervision and Testing)
Tian Yun (Tianjin Academy of Metrology, Supervision and Testing)
Yao Min (Beijing Institute of Metrology and Testing)
Participating drafters.
Chen Wuqing (Xinjiang Uygur Autonomous Region Metrology and Testing Research Institute)
Guo Shenhui (Qingdao Metrology Technology Research Institute)
Zhang Jiong (Jinan Changfeng Zhiyuan Instrument Technology Co., Ltd.)
Yu Xiaohu (Shenzhen Institute of Metrology and Quality Inspection)
content
Introduction (Ⅱ)
1 range(1)
2 References (1)
3 Terms (1)
4 Overview(1)
5 Metrology Characteristics(2)
5.1 Indication error(2)
5.2 Angle adjustment error(2)
5.3 Setpoint error(2)
5.4 Switching difference(2)
5.5 Insulation resistance(2)
6 Calibration Conditions(3)
6.1 Environmental conditions (3)
6.2 Standard device and ancillary equipment (3)
7 Calibration items and calibration methods (3)
7.1 Calibration and inspection items (3)
7.2 Calibration method(4)
7.3 Data processing(5)
8 Expression of calibration results (6)
9 Recalibration interval(6)
Appendix A Calibration Record Reference Format(7)
Appendix B Calibration Certificate Results Inner Page Reference Format (8)
Appendix C Example of Uncertainty Evaluation of Indication Error of Bimetal Thermometer (9)
Appendix D Example of Uncertainty Evaluation of Set Point Error of Electric Contact Bimetal Thermometer (12)
introduction
This specification is compiled in accordance with JJF 1071-2010 "Rules for Compilation of National Metrology and Calibration Specifications".
JJF 1059.1-2012 "Measurement Uncertainty Evaluation and Representation" requires evaluation of uncertainty, refer to
In JJF 1007-2007 "Terminology and Definition of Thermometer" and JB/T 8803-2015 "Bimetal Thermometer"
related definitions and technical content.
This specification replaces JJG226-2001 "Bimetal Thermometer". Compared with JJG226-2001, except for editorial revisions
The main technical changes are as follows.
--- Delete the calibration requirements for hysteresis, indication repeatability, switching repeatability and thermal stability;
--- The calibration standard was updated;
---The technical requirements for constant temperature equipment have changed;
--- Reduce the degree of deviation of the actual temperature of the constant temperature bath from the calibration point during the calibration process;
---Simplifies the calibration method of the set point error of the electric contact thermometer;
--- Reduced the temperature control rate of the constant temperature bath during the calibration process of the set point error;
--- Added the calculation formula of standard platinum resistance thermometer as the measurement standard;
--- An example of uncertainty assessment for calibration of indication error has been updated in the appendix;
--- An example of uncertainty assessment for set point error calibration has been added to the appendix.
The previous releases of this specification are as follows.
---JJG226-2001;
---JJG226-1989.
Bimetal Thermometer Calibration Specifications
1 Scope
This specification applies to the calibration of bimetal thermometers with a measurement range of (-80~500) °C.
2 Reference documents
This specification references the following documents.
JB/T 8803-2015 Bimetal Thermometer
For dated references, only the dated version applies to this specification; for undated references
The latest version (including all amendments) applies to this specification.
3 Terminology
The terms and definitions defined in JB/T 8803-2015 and the following apply to this specification.
A bimetal thermometer that can adjust the angle (0°~90°) between the indicating device and the axis of the detection element.
[Source. JB/T 8803-2015, 3.1]
A bimetal thermometer with electrical contacts.
[Source. JB/T 8803-2015, 3.2]
4 Overview
Bimetal thermometer is a temperature instrument suitable for medium and low temperature measurement. It uses two kinds of pure gold with different expansion coefficients.
Metal sheets or alloy sheets are firmly combined to form a temperature sensing element, which is generally wound into a spiral shape, one end of which is fixed, and the other end is fixed.
(Free end) is equipped with a pointer. When the temperature changes, the curvature of the temperature sensing element changes, and the free end rotates to drive the pointer.
The temperature value is indicated on the dial. A protective sleeve is installed on the outside of the temperature sensing element of the bimetal thermometer, and the dial is round.
Its typical structure is shown in Figure 1.
Fig. 1 Schematic diagram of typical structure of bimetal thermometer
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