MT 448-1995 Specification for ultrasonic vortex wind speed sensors for coal mines
Some standard content:
Coal Industry Standard of the People's Republic of China
Technical Conditions for Ultrasonic Vortex Wind Speed Sensors for Coal Mines
Subject Content and Scope of Application
MT 448-1995
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of ultrasonic vortex wind speed sensors for coal mines.
This standard applies to ultrasonic vortex wind speed sensors (hereinafter referred to as sensors) used in coal mine underground environmental monitoring. 2 Reference standards
GB191 Packaging, storage and transportation graphic symbols
GB2423.1 Basic environmental test procedures for electric and electronic products Test A: Low temperature test method GB2423.2 Basic environmental test procedures for electric and electronic products Test B: High temperature test method Basic environmental test procedures for electric and electronic products Test Db: Cyclic damp heat test method GB/T 2423.4
Basic environmental test procedures for electric and electronic products Test Ea: Impact test method GB 2423.51
GB 2423.8
GB 2423. 10
Basic environmental test procedures for electric and electronic products Test Ed: Free fall test method Basic environmental test procedures for electric and electronic products Test Fc: Vibration (sinusoidal) test method General requirements for explosion-proof electrical equipment for explosive atmospheres GB 3836. 1bzxz.net
Increased safety electrical equipment "e"
GB 3836.3
Explosion-proof electrical apparatus for explosive atmospheres
GB 3836. 4
Intrinsically safe circuits and electrical apparatus "i"Explosion-proof electrical apparatus for explosive atmospheres
GB/T4942.2 Random sampling method using random numbers for protection levels of low-voltage electrical enclosuresGB 10111
DC regulated power supply for coal mines
MT/T 408
3 Terminology
Ultrasonic vortex wind speed sensor
supersonic vortex sensor
A sensor that measures wind speed based on the Karman vortex principle by using the change in the amount of vortex modulation of the ultrasonic beam. 4 Technical requirements
4.1 Products shall comply with the requirements of this standard and be manufactured in accordance with drawings and technical documents approved through the prescribed procedures. 4.2 Working conditions:
Temperature: 0~～40℃;
Relative humidity: ≤98% (25℃);
Atmospheric pressure: 80～110kPa.
4.3 Storage temperature is -40～60℃.
4.4 The sensor must adopt intrinsically safe explosion-proof structure and meet the relevant provisions of GB3836.1, GB3836.3 and GB3836.4.
Approved by the Ministry of Coal Industry of the People's Republic of China on March 8, 1996 312
Implemented on August 1, 1996
4.5 Power supply:
Should meet the requirements of MT/T408.
4.6 Output signal format.
The following signal format should be used:
MT448-1995
Current: DC1~5mA (preferred), 4~20mA (load resistance 0~5002). Frequency: 5~15Hz, 200~1000Hz (pulse width greater than 0.3ms). Digital coding: The transmission rate is 300, 600, 1200, 2400, 4800, 9600b/s, and the level is not less than 3V. 4.7 The sensor housing should have a suspension or support structure suitable for underground installation conditions; the conversion part should have a dedicated suspension structure. 4.8 The protection performance of the sensor housing should comply with the IP54 protection level requirements in GB4942.2. 4.9 The cross-sectional area of the sensor cable should not be greater than 1.5mm2 and the transmission distance of the sensor should not be less than 1km. 4.10 Anti-corrosion measures shall be taken for the sensor housing, connectors and parts. The coating and plating shall be uniform, firm and of the same color. The printed circuit board shall be coated with three-proof (anti-corrosion, anti-mildew and moisture-proof) insulating paint at least twice. 4.11 The sensor shall indicate the measured value in m/s. When a digital indicator is used to indicate the measured value, its resolution shall be 0.1m/s. 4.12 Clear
Measuring range: 0.4~15m/s;
0. 5~25m/s.
Basic error shall not exceed ±0.3m/s when the measuring range is 0.4~15m/s, and shall not exceed ±0.4m/s when the measuring range is 0.5~~25m/s. In the range of 0~~40℃, the fluctuation of the working frequency of the ultrasonic wave in the wind speed sensitive element shall not exceed ±3kHz. After the stability test, the drift of the sensor shall comply with the provisions of 4.13. After the storage temperature test, the sensor shall comply with the provisions of 4.13. 4.16
After the humidity and heat test, the sensor shall comply with the provisions of 4.13. 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 4.13. 4.18
4.19After 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 4.13. 4.20
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 4.13. 5 Test method
5.1 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.
5.2 Determination of basic error.
5.2.1 Equipment and instruments:
Wind tunnel wind speed range: 0.2~25m/s;
Airflow non-uniformity in the working section of the wind tunnel shall not exceed 1.5%, and instability shall not exceed 0.5%; the hydraulic diameter of the wind tunnel test section shall be greater than 250mm, and at the same time greater than 5 times the hydraulic radius of the sensor part placed in the wind flow; the Pitot tube coefficient is 1.004~0.998, and the deviation is not greater than 0.5%; the allowable error of the micromanometer is not greater than ±0.8Pa; the measuring range of the moving trough mercury barometer is 81~110(107)kPa, and the accuracy is ±40Pa; the measuring range of the standard thermometer is 0~50℃, and the graduation value should not be greater than 0.2℃. Measurement steps:
Fix the converter part in the middle of the wind tunnel test section, and make the airflow channel axis parallel to the wind tunnel axis, and the non-parallelism should be less than 5 degrees.
Measure the test environment parameters and calculate the air density according to formula (1): 313
Where: p——air density, kg/m2;
-atmospheric pressure, Pa;
MT 448-1995
0=.3.483×10
T——dry air temperature, (t+273)k, in degrees Celsius. (1)
c. During the test of each sensor, the ambient temperature fluctuation should not exceed ±1℃; d. Select the measuring point according to Table 1. The wind speed in the wind tunnel should increase gradually from low to high. After the wind flow stabilizes at the specified wind speed at the measuring point, measure the micropressure counter value, sensor indication value and output signal value, and take the arithmetic average of three consecutive measured values as the measurement result of the wind speed measuring point. Table 1
Measurement range
5.2.3 Error calculation:
The real wind speed is calculated according to formula (2):
Where:——real wind speed, m/s,
pWindflow air density, kg/m;
p--micromanometer reading, Pa;
—Pitot tube coefficient.
b. The measurement error is calculated according to formula (3):
The wind speed value converted from the indication value or output signal value of a certain measuring point, m/sWhere:vi-—
-real wind speed value, m/s.
5.3 Working frequency fluctuation:
Put the sensor in a temperature control box, keep it at 20℃ for 2h, and measure the working frequency f of the ultrasonic sensitive element. Then, keep it at 0℃ and 40℃ for 2h respectively, and measure the working frequency f of the ultrasonic sensitive element: Calculate the frequency fluctuation according to the following formula. The frequency fluctuation is calculated according to formula (4):
△=ff. ·
5.4 Stability test:
The sensor is operated continuously for 7 days, and the wind speed of 10m/s is measured 3 times every 24 hours, and the average value is taken. 5.5 Storage temperature test.
5.5.1 Low temperature storage test:
Perform according to test Ab method in GB2423.1. The temperature is -40±3℃, and the duration is 16h. The sensor is not packaged, not powered, and no intermediate detection is performed. After the test, it is restored to the conditions specified in 5.1 in the test box and maintained for 2 hours, and then the basic error is measured. 5.5.2 High temperature storage test:
Per GB2423.2. Test Bb method is used. Under the condition of +60±2℃, the duration is 16h. The sensor is not packaged, not powered, and no intermediate detection is performed. After the test, it is restored to the conditions specified in 5.1 in the test box for 2h, and then the basic error is measured. 5.6 Humidity test:
According to the test Db method in GB2423.4. Under the condition of 40±2℃ and relative humidity of 93%±3%, the duration is 12d. The sensor is not packaged, not powered, and no intermediate detection is performed. After the test, it is restored to the conditions specified in 5.1 for 2h, and then the basic error is measured. 5.7 Vibration test:
MT448—1995
According to the test Fc method in GB2423.10. Severity level: sweep frequency range 10~150Hz, acceleration amplitude 50m/s2, 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 the basic error is determined. 5.8 Impact test:
Performed according to the test Ea method in GB2423.5. Severity level: Peak acceleration is 500m/s2, pulse duration is 11±1ms, 3 axes are impacted continuously in each direction for 3 times (18 times in total), the sensor is not packaged, not powered, and no intermediate inspection is performed. After the test, an appearance inspection is performed and the basic error is determined.
5.9 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, not powered, and no intermediate inspection is performed. After the test, an appearance inspection is performed and the basic error is determined.
5.104.10~4.14 After each test, before checking the performance, it is allowed to recalibrate the sensor. 5.11 The explosion-proof performance test method of the sensor shall be carried out by an authorized explosion-proof inspection agency in accordance with the provisions of GB3836.1, GB3836.3 and GB3836.4.
6 Inspection rules
6.1 Factory inspection
6.1.1 The quality inspection department of the manufacturer shall conduct inspection on each sensor. Only after the inspection is qualified and the certificate is issued can the sensor be shipped out of the factory. 6.1.2 See Table 2 for the factory inspection items.
6.2 Type inspection
6.2.1 Type inspection shall be conducted in any of the following cases: a. When a new product or old product is transferred to a factory for trial production and type identification; b.
After formal production, if there are major changes in structure, materials, and processes that may affect product performance; once every two years for sensors in normal production;
When production is resumed after more than two years of suspension,
When the factory inspection results are significantly different from the last type inspection, when the national quality supervision and inspection agency makes a request. 6.2.2 Type inspection items are shown in Table 2.
6.2.3 Type inspection shall be conducted by a quality supervision and inspection agency authorized by the state. 6.3 Sampling
From sensors that have passed the factory inspection, the method specified in GB10111 shall be used. The sampling base shall not be less than 10 units, and the sampling quantity shall not be less than 3 units.
6.4 Judgment rules
The number of sensors to be inspected is 3 units. During the inspection, if one of the items in 4.12, 4.13 and 4.14 fails, or two of the items in other items fail, the batch of products shall be judged as unqualified. If one of the items other than 4.12, 4.13 and 4.14 fails, all items shall be re-inspected twice. If there are still unqualified items, the batch of products shall be judged as unqualified. 315
Note: ○ indicates an item that must be carried out.
Marking, packaging, transportation, storage
7.1 Marking
MT448—1995
Technical requirements
Factory inspection
The housing of the sensor shall be marked with "Ex", "MA" and measuring instrument markings in obvious places. The nameplate of the sensor should have the following information: product model and name;
\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.
Packing mark:
shipping mark should comply with relevant transportation regulations; operation mark should comply with GB191 regulations.
7.2 Packaging
7.2.1 The packaging should adopt composite protective packaging type, which has the ability to prevent rain, moisture, dust and vibration. 7.2.2
The following documents should be included in the packaging box:
Type inspection
Product certificate;
Product instruction manual;
Packing list.
7.3 Transportation
MT448-1995
The packaged products should be suitable for road, rail, water and air transportation. 7.4 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 interpretation. 317If one of the other items in 14 fails to meet the standards, the whole item shall be re-inspected twice. If there are still any failures, the batch of products shall be judged as unqualified. 315
Note: ○ indicates items that must be carried out.
Marking, packaging, transportation, storage
7.1 Marking
MT448—1995
Technical requirements
Factory inspection
The housing of the sensor shall be marked with "Ex", "MA" and measuring instrument markings in obvious places. The nameplate of the sensor should have the following information: product model and name;
\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.
Packing mark:
shipping mark should comply with relevant transportation regulations; operation mark should comply with GB191 regulations.
7.2 Packaging
7.2.1 The packaging should adopt composite protective packaging type, which has the ability to prevent rain, moisture, dust and vibration. 7.2.2
The following documents should be included in the packaging box:
Type inspection
Product certificate;
Product instruction manual;
Packing list.
7.3 Transportation
MT448-1995
The packaged products should be suitable for road, rail, water and air transportation. 7.4 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 interpretation. 317If one of the other items in 14 fails to meet the standards, the whole item shall be re-inspected twice. If there are still any failures, the batch of products shall be judged as unqualified. 315
Note: ○ indicates items that must be carried out.
Marking, packaging, transportation, storage
7.1 Marking
MT448—1995
Technical requirements
Factory inspection
The housing of the sensor shall be marked with "Ex", "MA" and measuring instrument markings in obvious places. The nameplate of the sensor should have the following information: product model and name;
\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.
Packing mark:
shipping mark should comply with relevant transportation regulations; operation mark should comply with GB191 regulations.
7.2 Packaging
7.2.1 The packaging should adopt composite protective packaging type, which has the ability to prevent rain, moisture, dust and vibration. 7.2.2
The following documents should be included in the packaging box:
Type inspection
Product certificate;
Product instruction manual;
Packing list.
7.3 Transportation
MT448-1995
The packaged products should be suitable for road, rail, water and air transportation. 7.4 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 interpretation. 317
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