This regulation is applicable to the initial verification, subsequent verification and in-use inspection of catalytic combustion methane detectors used in mines. JJG 678-2007 Verification Regulation for Catalytic Combustion Methane Detectors JJG678-2007 Standard download decompression password: www.bzxz.net
This regulation is applicable to the initial verification, subsequent verification and in-use inspection of catalytic combustion methane detectors used in mines.

National Metrology Verification Regulation of the People's Republic of China JJG678-—2007
Catalysis Combustion Type Methane Measuring Device2007-08-21Promulgated
Implementation on 2008-02-21
Promulgated by the General Administration of Quality Supervision, Inspection and QuarantineJJG678-—2007
Catalysis Combustion Type Methane Measuring DeviceVerification Regulation of Catalysis Combustion Type Methane Measuring DeviceJJG678-2007
Replaces JJG678—1996
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on August 21, 2007, and came into effect on February 21, 2008.
Responsible unit: National Technical Committee for Environmental Chemical Metrology Main drafting unit: Chongqing Lianneng Industry and Trade Co., Ltd., China National Institute of Metrology
National Mine Safety Metrology Station
Participating drafting units: Jinan Metrology Verification Institute National Mine Safety Metrology Station Urumqi Branch Chongqing Ke'an Electronics Co., Ltd.
This regulation is entrusted to the National Technical Committee for Environmental Chemical Metrology for interpretation. Main drafters of this regulation:
JJG678-2007
Chen Yonghua (China National Institute of Metrology) Zhou Zongfu (Chongqing Lianneng Industry and Trade Co., Ltd.) Chen Fumin (National Mine Safety Metrology Station) Participating drafters:
Wang Limin (Jinan Metrology Verification Institute)
Cao Zhigang (China National Institute of Metrology) Dong Zibing (Urumqi Branch of National Mine Safety Metrology Station) Du Jianguo (Chongqing Ke'an Electronics Co., Ltd.) 1
Scope·
3 Metrological performance requirements·||t t||Indication error·
Alarm error·
Response time·
Alarm sound level and signal
Load characteristics
General technical requirements·
Appearance·
Marking and accessories
Power-on inspection
5 Measuring instrument control·
Verification conditions…
Verification items.
Verification method·
Processing of verification results|| tt||5.5 Calibration cycle·
Appendix A
Appendix B
Format of the inner pages of the calibration certificate
Format of the inner pages of the calibration result notice
JJG678-2007
Appendix C
Format of original calibration records for portable instruments
Appendix D
Format of original calibration records for fixed instruments
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1 Scope
JJG678—2007
Calibration procedure for catalytic combustion methane detectors This procedure applies to the initial calibration, subsequent calibration and in-use inspection of catalytic combustion methane detectors (hereinafter referred to as instruments) used in mines.
2Overview
The instrument applies the principle of carrier thermal catalytic combustion. The carrier catalytic element constitutes a measuring bridge. When there is methane gas in the environment where the instrument is located, methane produces flameless combustion on the surface of the catalytic element, causing the resistance of the carrier catalytic detection element to change, and the bridge circuit is unbalanced to generate a signal output. The signal size is linearly proportional to the methane content, thereby realizing the detection and alarm of the methane content.
Catalytic combustion methane detectors are divided into two categories: portable and fixed. Fixed methane detectors are also called methane sensors. They are used for the determination and alarm of methane content in mines. When the methane concentration reaches the alarm set point, the instrument sends out sound and light alarm signals.
3Metering performance requirements
3.1Indication error
The indication error is expressed in absolute error. Under the specified working conditions, the maximum difference between the indication and the standard value of the instrument should not exceed the provisions of Table 1.
Indication error
Measurement range/%CH4Www.bzxZ.net
Segment/%CH4
Maximum allowable error/%CH
3.2 Alarm error
When the instrument alarms, the difference between the indication and the alarm setting value should not exceed ±0.10%CH4. 3.3 Response time
The instrument for diffusion sampling should not exceed 20S, and the instrument for suction sampling should not exceed 10S. 3.4 Drift
2
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