MT 446-1995 Technical requirements for electrochemical carbon monoxide sensors for coal mines
Some standard content:
Coal Industry Standard of the People's Republic of China
Technical Conditions for Electrochemical Carbon Monoxide Sensors for Coal Mines
Subject Content and Scope of Application
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of electrochemical carbon monoxide sensors for coal mines.
This standard applies to electrochemical carbon monoxide sensors (hereinafter referred to as sensors) used in underground coal mine environmental monitoring. 2 Referenced Standards
GB 191
Packaging, Storage and Transportation Pictorial Marking
GB 2423. 1
GB 2423. 4
GB 2423. 5
GB 2423. 8
GB 2423. 10
GB 3836. 1
GB 3836.3
Basic environmental test regulations for electric and electronic productsBasic environmental test regulations for electric and electronic productsBasic environmental test regulations for electric and electronic productsBasic environmental test regulations for electric and electronic productsBasic environmental test regulations for electric and electronic productsTest A: Low temperature test method
Test B: High temperature test method
Test Db: Alternating damp heat test method
Test Ea: Impact test method
Test Ed: Free fall test method
Basic environmental test regulations for electric and electronic productsTest Fc: Vibration (sinusoidal) test methodGeneral requirements for explosion-proof electrical apparatus for explosive atmospheresExplosion-proof electrical apparatus for explosive atmospheresIncreased safety electrical apparatus "e"Explosion-proof electrical apparatus for explosive atmospheresIntrinsically safe circuits and electrical apparatus ""GB/T4942.2Protection levels of low-voltage electrical enclosuresRandom sampling method using random numbers GB 10111
MT/T408 DC regulated power supply for coal mines
3 Technical requirements
3.1 The product shall comply with the requirements of this standard and be manufactured according to the drawings and technical documents approved by the prescribed procedures. 3.2 Working conditions:
Temperature: 0~40℃
Relative humidity: ≤98% (25℃),
Atmospheric pressure: 80~110kPa;
Speed: 0~8m/s.
3.3 Storage temperature is -40~60℃.
3.4 The sensor must adopt an intrinsically safe explosion-proof structure and meet the relevant provisions in GB3836.1, GB3836.3, and GB3836.4.
3.5 Power supply:
Should comply with the requirements of MT/T408.
Approved by the Ministry of Coal Industry of the People's Republic of China on March 8, 1996 296
Implemented on August 1, 1996
3.6 Output signal format
MT 446--- 1995
Current: DC1~5mA (preferred) 4~20mA (load resistance 0500α); frequency 5~15Hz200~1000Hz (pulse width greater than 0.3ms), digital coding: transmission rate is 300, 600.1200, 2400, 4800, 9600b/s, level is not less than 3V. 3.7 The sensor housing should have a hanging or supporting structure suitable for installation conditions. 3.8 The protection performance of the sensor housing should comply with the IP54 protection level specified in GB/T4942.2. 3.9 The cross-sectional area of the sensor cable should not be greater than 1.5 mm, and the transmission distance of the sensor should not be less than 1km. 3.10 Anti-corrosion measures should be taken for the sensor housing, connectors and parts. The coating and plating should be uniform, firm and consistent in color. The printed circuit board should be coated with three-proof (anti-corrosion, anti-mildew and moisture-proof) insulating paint at least twice. 3.11 When the sensor adopts a split structure, the length of the external cable of the probe should not be less than 5m. 3.12 The sensor should express the measurement value in 1×10-* units. When a digital indicator is used to indicate the measurement value, its resolution should be 1×10- carbon dioxide.
3.13 The sensor should be powered by a power box equipped with a backup battery, or a backup battery should be installed in the sensor to ensure that the chemical sensitive elements in the sensor are not affected by power interruption. 3.14 The measuring range of the sensor is: 0~~99(100)×10-°; 0~200×10-bZxz.net
0~500×10-6
0~1000×10-
3.15 Basic error:
The sensor with a measuring range less than 500×10-' shall comply with the provisions of Table 1: Table 1
Measurement range
Absolute error
The sensor with a measuring range of 0~1000×10- shall comply with the provisions of Table 2: Table 2| |tt||Measurement value
>50-200
Basic error
1X10-6CO
Relative error, %
1×10-6CO
Basic error
±(4+3% of measurement value)
±(4+5% of measurement value)
3.16 When the load resistance of the sensor whose output signal format is current changes within the range of 0~~5000, the change of its output signal value shall not exceed the provisions of 3.15.
When the load resistance of the sensor whose output signal format is frequency changes within the range of 0~500, the change of its output signal value shall not exceed the provisions of 3.15, and its pulse width shall not be less than 0.3S. 3.17 Stability:
The basic error of the sensor working continuously for 7d shall not exceed the provisions of 3.15. 3.18 Response time:
The response time of the sensor should not exceed 40s. 3.19 Alarm function:
MT 446--1995
3.19.1 The sensor with alarm function should be able to set the alarm point arbitrarily within the measurement range, and the difference between the alarm value and the set value should not be greater than ±2×10-\ carbon monoxide.
3.19.2 The sound pressure level of the sound signal at a distance of 1m from the alarm should not be less than 85dB(A), and the light signal should be clearly visible at a distance of 20m.
3.20 The drift of the display value of the sensor under the wind speed of 8m/s should not be greater than ±2×10-\ carbon monoxide. 3.21
The operating temperature test of the sensor should comply with the provisions of 3.15. After the storage temperature test, the sensor should comply with the provisions of 3.15. 3.22
After the humidity and heat test, the sensor shall comply with the provisions of 3.15. 3.23
After the vibration test, the connectors and parts of the sensor shall not be loose or fall off, and shall comply with the provisions of 3.15. 3.241
After the impact test, the sensor shall have no signs of damage, and the connectors and parts shall not be loose or fall off; and shall comply with the provisions of 3.15. After the drop test, the connectors and parts of the sensor shall not be loose or fall off, and shall comply with the provisions of 3.15. 4 Test methods
4.1 Environmental conditions
Unless otherwise specified in the environmental test or relevant standards, the test shall be carried out under the following environmental conditions: temperature: 15~~35℃, relative humidity: 45%~～75%; atmospheric pressure: 86~106kPa.
4.2 Test gas samples and instruments
4.2.1 Test gas samples
Standard gas samples of carbon monoxide in the air (hereinafter referred to as standard gas samples), with an uncertainty of 3%. 4.2.2 Test instruments
4.2.2.1 Gas flow meter
Measuring range: 30~300mL/min; accuracy: 2.5 level. 4.2.2.2 Stopwatch
Division value: 0.01s.
4.2.2.3 DC milliammeter
0~100 mA, 0.2 level.
4.2.2.4 Frequency meter
0～1000kHz; accuracy: ≤1×10-6. 4.2.2.5 DC regulated power supply
Output voltage: 0~30V, output current: 2A. 4.3 Basic error determination
The basic error determination device is shown in Figure 1.
MT 446-1995
Figure 1 Schematic diagram of basic error determination
1 Test chamber; 2-sensor 3-gas injection device, 4-preheating coil, 5-flow meter: 6-clean air bottle; 7-test gas sample bottle, 8-regulating valve
Use the gas injection device provided by the manufacturer to sequentially introduce clean air and the three standard gases specified in Table 3 into the sensor according to the flow rate during calibration. Table 3
Measurement range
Not more than 500
More than 500
102480% Measurement upper limit
1×10-6CO
After each concentration of gas sample is introduced for 3 minutes, read the display value and output signal value (converted to carbon monoxide concentration value). Repeat the measurement 4 times, and take the arithmetic mean of the next 3 times, which should not exceed the provisions of 3.15. 4.4 Load characteristic test
Convert the difference in output signal when the sensor is stable in the air with an external load resistance of 500α and 0α into the carbon monoxide concentration value. 4.5 Stability determination
Put the adjusted sensor into the device shown in Figure 1 and run it continuously for 7 days. Every 12 hours, pass clean air and a standard gas sample of about 50% of the measuring range in turn at the flow rate during calibration for 3 minutes each, and record the indicated value and output signal value. The sensor shall not be adjusted during the test. 4.6 Response time determination
The determination device is shown in Figure 2. The gas injection device provided by the manufacturer should be used on the diffusion sampling head. At the flow rate during calibration, a carbon monoxide gas sample of about 80% of the measuring range should be passed for 3 minutes, and the indicated value should be read. Then, clean air is introduced. After the zero point of the sensor is stable, the gas injection device that introduces the original carbon monoxide gas sample at the flow rate during calibration is quickly replaced with the sampling head, and the time required for the sensor indication value to reach 90% of the original indication value is recorded. The measurement is repeated three times and the arithmetic mean is taken.
4.7 Alarm test
MT 446- 1995
Figure 2 Schematic diagram of response time determination
1 Clean air hose, 2- Full clean air injection device: 3 Diffusion sampling head: 4-Sensor, 5 Exhaust port, 6 Ventilation cover support: 7-Test gas sample injection device: 8 Test gas sample hose 4.7.1 Alarm function test
Set the sensor alarm point to the value specified at the factory. After the zero point of the sensor is stable, slowly introduce a gas sample with a carbon monoxide concentration slightly greater than the set alarm point, record the sensor indication value at the moment when the sound and light signals appear, and calculate the difference between the alarm point and the indication value. 4.7.2 Measurement of alarm sound level intensity
The alarm sound performance is measured with a sound level meter, and the ambient noise should be less than 50dB (A). Place the sound level meter 1m in front of the axis of the alarm sounder of the sensor, measure 3 times, and take the arithmetic mean. 4.7.3 Alarm light signal
The test is observed in a dark environment 20m away from the sensor. 4.8 Wind speed effect test
Hang the sensor in the test wind tunnel, and adjust the reference point of the sensor when the wind flow is zero. Then adjust the wind speed to 8+8\m/s, and artificially rotate the sensor around the hanging axis to find the position affected by the wind speed. Fix it at this position, record the indicated value once every 30s, and record it 3 times in total. Take the difference between the arithmetic mean and the reference point as the drift. 4.9 Working temperature test
The temperature of the standard gas sample introduced into the sensor during the test should be consistent with the test requirement temperature. 4.9.1 Low temperature working test
Perform according to the test Ab method in GB2423.1. Under the condition of 0±3℃, the sensor is powered on and stabilized for 2h, and then the basic error is measured. The basic error is measured once every hour thereafter, for a total of 3 times. The arithmetic mean is taken as the measured value. 4.9.2 High temperature working test
Perform according to the test Bb method in GB2423.2. Under the condition of 40±2℃, the sample is powered on and stabilized for 2h, and then the basic error is measured. The basic error is measured once every hour thereafter, for a total of 3 times. The arithmetic mean is taken as the measured value. 4.10 Storage temperature test
4.10.1 Low temperature storage test
Perform according to the test Ab method in GB2423.1. Under the condition of -10±3℃, the duration is 16h. The sensor is not packaged, not powered on, and no intermediate detection is performed. After the test, the test chamber is restored to the conditions specified in 4.1 and maintained for 2 hours, and then the basic error is measured. 4.10.2 High temperature storage test
Perform according to the test method Bb in GB2423.2. The temperature is +45±2℃, and the duration is 16 hours. The sensor is not packaged, 300
MT 446--1995
No power is supplied, and no intermediate detection is performed. After the test, the test chamber is restored to the conditions specified in 4.1 and maintained for 2 hours, and then the basic error is measured. 4.11 Condensation heat test
Perform according to the test method Db in GB2423.4. The temperature is 40±2℃, the relative humidity is 93%±3%, and the duration is 12 days. The sensor is not packaged, no power is supplied, and no intermediate detection is performed. After the test, the test chamber is restored to the conditions specified in 4.1 for 2 hours, and then the basic error is measured. 4.12 Vibration test
Performed according to the test Fc method in GB2423.10. Severity level: sweep frequency range 10~150Hz, acceleration amplitude 50m/s, vibration number 5 times. The sensor is not packaged, not powered, and no intermediate detection is performed. After the test, an appearance inspection is performed, and then the basic error is measured. 4.13 Impact test
Performed according to the test Ea method in GB2423.5. Severity level: peak acceleration is 500m/s*, pulse duration is 11±1ms, and the three axes are continuously impacted 3 times in each direction (a total of 18 times). The sensor is not packaged, not powered, and no intermediate detection is performed. After the test, an appearance inspection is performed, and then the basic error is measured.
4.14 Drop test
Performed according to the test Ed method in GB2423.8. Severity level: Drop height is 0.5m, free fall onto a smooth, hard concrete surface in the normal use direction for a total of 2 times. The sensor is not packaged, powered, and no intermediate inspection is performed. After the test, an appearance inspection is performed, and then the basic error is measured.
4.154.10~4.14 After each test, before checking the performance, it is allowed to recalibrate the sensor. 4.16 The explosion-proof performance test method of the sensor shall be carried out in accordance with the regulations of GB3836.1, GB3836.3 and GB3836.4 by an authorized explosion-proof inspection agency.
5 Inspection rules
5.1 Factory inspection
5.1.1 It should be carried out by the quality inspection department of the manufacturer. It can only be shipped after passing the inspection and issuing a certificate of conformity. 5.1.2 See Qiu 4 for factory inspection items.
Technical requirements clause
Factory inspection
Type inspection
Note: ○ indicates items that must be carried out.
5.2 Type inspection
MT 446--1995
Continued Table 4
Technical requirements clause
5.2.1 Type inspection should be carried out in any of the following situations: a.
When new products or old products are transferred to the factory for trial production and type identification, factory inspection
After formal production, if there are major changes in structure, materials, and processes that may affect product performance, the normal production of sensors is once every 2 years;
When production is resumed after suspension for more than 2 years;
When the factory inspection results are significantly different from the last type inspection: When the national quality supervision and inspection agency makes a request. 5.2.2 Type inspection items are shown in Table 4.
5.2.3 Type inspection shall be conducted by a quality supervision and inspection agency authorized by the Ministry of Coal Industry. 5.2.4 Sampling
Type inspection
It shall be conducted according to the method specified in GB10111 from sensors that have passed the factory inspection. The sampling base shall not be less than 10 units, and the sampling quantity shall not be less than 3 units.
Judgment rules
There shall be 3 sensors to be inspected. During the inspection, if one of the items in 3.15, 3.16, 3.17 and 3.19.1 fails, or two of the items in other items fail, the batch of products shall be judged as unqualified. If one of the items in other items other than 3.15, 3.16, 3.17 and 3.19.1 fails, all items shall be doubled for re-inspection. If there are still failures, the batch of sensors shall be judged as unqualified. 6 Marking, packaging, transportation and storage
6.1 Marking
6.1.1 The sensor housing should be marked with "Ex", "MA\ and measuring instrument markings in obvious places. 6.1.2
The nameplate of the sensor should have the following contents: product model and name;
There is an "Ex" mark in the upper right corner,
Explosion-proof mark:
Explosion-proof inspection certificate number;
Coal mine safety mark number;
Manufacturing measuring instrument license number:
Related equipment model;
Main technical parameters;
Protection level;
Manufacturer name,
Factory number or date.
6.1.3 Packaging mark
The shipping mark should comply with the relevant transportation regulations;MT 446—1995
b. The operation mark should comply with the provisions of GB191. 6.2 Packaging
6.2.1 The packaging should adopt a composite protective packaging type with rainproof, moisture-proof, dustproof and vibration-proof capabilities. 6.2.2 The following documents should be included in the packaging box:
b. Product certificate;
c. Product instruction manual;
c. Packing list.
6.3 Transportation
The packaged sensor should be suitable for road, rail, water and air transportation. 6.4 Storage
It should be stored in a well-ventilated warehouse without corrosive gas. Additional notes:
This standard was proposed by the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the jurisdiction of the Gas Detection and Rescue Equipment Branch of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard was drafted by the Fushun Branch of the China Coal Research Institute. The main drafter of this standard is Miao Yaxin.
This standard is entrusted to the Fushun Branch of the China Coal Research Institute for its interpretation. 303
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