MT/T 440-1995 Method for determination of mine ventilation resistance
Some standard content:
Coal Industry Standard of the People's Republic of China
Method for Determination of Mine Ventilation Resistance
1 Subject Content and Applicable Examples
This standard specifies the instruments, measurement steps, calculation and processing of measurement results for measuring mine ventilation resistance. This standard applies to the measurement of ventilation resistance in coal mine tunnels. 2 Terminology
2.1 Main route
MT/T440-1995
When measuring the ventilation resistance of a mine, the ventilation route selected from the air inlet shaft (or the bottom of the shaft), through the air inlet tunnel, mining area, return air tunnel, return air shaft to the wind.
2.2 Secondary route
When measuring the ventilation resistance of a mine, the ventilation route selected other than the main route. 3 Instruments
The following measuring instruments should be calibrated and used within the validity period. a.
Ordinary empty box barometer:
Measuring range 80~107kPa (equivalent to 600~800mmHg), minimum graduation value 50Pa Inclined differential pressure gauge:
Measuring range 0~3000Pa, minimum graduation value 10Pa; Precision barometer:
Measuring range 83.6~114kPa, minimum graduation value 25Pa; d. Ventilation wet and dry thermometer:
Measuring range -25 ~ +50 ℃, minimum scale value 0.2 ℃; Pitot tube:
Correction coefficient 0.998 ~ 1.004,
Low speed anemometer:
Measuring range 0.2 ~ 5m/s, starting wind speed ≤ 0.2m/s Medium speed anemometer:
Measuring range 0.4 ~ 10m/s, starting wind speed < 0.4m/s; h. High speed anemometer:
Impeller: Measuring range 0.8 ~ 25m/s, starting wind speed ≤ 0.5m/s; Cup type: Measuring range 1.0 ~ 30m/s, starting wind speed ≤ 0.8m/s; i. Stopwatch:
Minimum scale value 1s;
Small. Steel tape measure:
2m steel tape measure: measuring range 0~2m, minimum graduation value 1.0mm; approved by the Ministry of Coal Industry of the People's Republic of China on March 8, 1996 158
implemented on August 1, 1996
MT/T 440-1995
30m steel tape measure: measuring range 0~~30m, minimum graduation value 1.0mm; k. Rubber tube (or plastic tube):
Inner diameter 4~5mm;
1. Rubber tube joint:
Inner diameter 3~4mm, outer diameter 5~6mm, length 50~80mm. 4 Measurement steps
4.1 Measurement route selection
Select the main and secondary routes for measurement on the ventilation system diagram. At the same time, consider measuring the route within one work shift; when the measurement route is long, it can be measured in sections and groups. 4.2 Selection of measuring points
First, arrange the measuring points on the ventilation system diagram according to the selected measurement route and number them in sequence. Then determine the location of the measuring points according to the actual situation underground and mark them.
When selecting measuring points, the following requirements should be met:
a. The measuring point should be selected before (or after) the wind separation point or wind combination point. The selection in front should not be less than 3 times the width of the roadway, and the selection in the back should not be less than 8 times the width of the roadway;
b. When it is necessary to select points at the turning point of the roadway or the place where the cross-section changes greatly, the selection in front should not be less than 3 times the width of the roadway; the selection in the back should not be less than 8 times the width of the roadway;
c. The roadway within 3m before and after the measuring point should be well supported, and there should be no accumulation in the roadway; d. The pressure difference between the two measuring points should not be less than 20Pa. 4.3 Differential pressure gauge method
4.3.1 Wind pressure measurement
Starting from measuring point 1, a pitot tube is set at each of measuring points 1 and 2. Generally, a differential pressure gauge is installed 6 to 8 meters downwind of measuring point 2. The pitot tube should be set at a place with stable wind flow, facing the wind flow. The differential pressure gauge should be installed close to the tunnel wall and stable, and zero or record the initial reading. The rubber tube should be prevented from folding and being blocked by water, dirt, etc. After the air temperature in the rubber tube is equal to the air temperature in the tunnel, the two rubber tubes are installed on the differential pressure gauge. After the liquid level of the differential pressure gauge is stable, the reading is taken and filled in Table A4. After measuring points 1 and 2, the differential pressure gauge can be left unchanged, and the measurement between measuring points 2 and 3 is carried out. The measurement is carried out in the order of the measuring points until the entire route is measured.
The measurement sequence can also be carried out in the opposite direction of the wind flow. 4.3.2 Wind speed measurement
Measure the wind speed with an anemometer. It is necessary to measure three times and take the average wind speed value. And fill in Table A2. 4.3.3 Atmospheric physical parameter measurement
Measure the atmospheric pressure with an empty box barometer; measure the dry bulb temperature and wet bulb temperature of the air with a ventilation dry and wet thermometer. And fill in Table A3.
4.3.4 Measurement of tunnel cross-sectional area and perimeter parameters According to the tunnel cross-sectional shape of the measuring point, use a steel tape measure to measure. And fill in Table A1. 4.3.5 Measurement of the distance between measuring points
Measure the distance between two measuring points with a steel tape measure. And fill in Table A1. 4.4 Barometer method
4.4.1 Wind pressure measurement
4.4.1.1 Point-by-point measurement method:
Adjust two precision barometers (I, I) at the wellhead or well bottom parking lot and record the initial readings. Instrument I stays in place to monitor the atmospheric pressure changes and records the readings every 10 to 15 minutes. Instrument II measures the absolute static pressure of the wind flow at each measuring point in the order of the measuring points. And fill in Table A5159
4.4.1.2 Dual-point simultaneous measurement method:
MT/T 4401995
At measuring point 1, adjust two precision barometers (I, I) and record the initial readings. Then instrument 1 stays in place and instrument II is placed at measuring point 2. The two instruments read the readings simultaneously within the agreed time. Then move instrument 1 to measuring point 2 and read the readings at the same time. Keep instrument 1 still and move instrument 1 to measuring point 3. Then read the readings of both instruments at the same time within the agreed time. Continue in this way until the measurement is completed. Fill in Table A6. 4.4.2 Wind speed measurement Same as 4.3.2
4.4.3 Atmospheric physical parameter measurement Same as 4.3.34.4.4 Tunnel cross-sectional area and perimeter parameter measurement Same as 4.3.44.4.5 Measurement of measuring point spacing Same as 4.3.5
4.4.6 Measurement of measuring point elevation
The elevation of each measuring point is given by the land surveying department.
5 Calculation of measurement results
5.1 Calculation of air density
The air density is calculated according to formula (1):
p=3. 484 ×10-P0. 37794Pb
Wherein: - air density, kg/m~;
Atmospheric pressure at the measuring point, Pa;
Relative air humidity, %;
When the temperature at the measuring point is tC, the absolute saturated water vapor pressure of the air, Pa; Pah -
Air temperature ℃.
5.2 Calculation of tunnel cross-sectional area and perimeter
According to the shape of the tunnel cross-sectional area, calculate its cross-sectional area and perimeter. 5.3 Calculation of average wind speed
The arithmetic average of the three actual wind speed values at each measuring point is taken. 5.4 Calculation of air volume
The air volume is calculated according to formula (2):
Wherein: q——air volume at the measuring point, m2/s;
S—cross-sectional area of the tunnel at the measuring point, m2;
Average wind speed at the measuring section, m/s.
5.5 Calculation of dynamic pressure
The dynamic pressure is calculated according to formula (3):
Wherein: ha-dynamic pressure at the measuring point, Pa.
（3）
5.6 Calculation of ventilation resistance
5.6.1 Ventilation resistance between two measuring points
5.6.1.1 Calculate by differential pressure meter method according to formula (4): Wherein: hxi,- ventilation resistance between two measuring points, Pa; hi,- pressure difference between two measuring points, Pa;
hd;- dynamic pressure value at measuring point i, Pa,
hdj-- dynamic pressure value at measuring point i, Pa.
5.6.1.2 Barometer method
Point-by-point measurement method is calculated according to formula (5):
MT/T 440—1995
huij-hi,+haihdj
hnj(h',—h')-\(h\;--h\)+(Z,-Z,)pig+(ha:—ha,)In the formula: \——correction coefficient of barometer (I, Ⅱ); h',h are the readings of barometer (I) at measuring point ij, Pa; h\,h\j—readings of barometer (I) when measuring h',h',, Pa; ZZ, the elevation of measuring point ii, m,
,—average value of air density at measuring point ij, kg/m; -gravity acceleration, m/s2.
The simultaneous determination method of two measuring points is calculated as follows:
hn;=k(h';h')-n\(h\;-h\)+(Z;-Z,)pug+(hdsha,)-the reading of the barometer (I) at the measuring point 讠, i,Pa. Where: h\, h\j-
5.6.2 Calculation of total resistance of the measurement route
The total resistance of the measurement route is calculated as follows: htr -- Ehrii
Where: hr——Total resistance of the measurement route, Pa; h—Total reading at measuring point j of the measurement route. 5.7 Wind resistance of tunnel
5.7.1 Calculation of wind resistance between two points
The wind resistance between two points is calculated as follows:
Where: R,—wind resistance between measuring points i and j, N·s/m°; quiy
—arithmetic mean of wind volume at measuring points i and i, m\/s. 5.7.2 Calculation of standard wind resistance between two points
(（4）
（5）
The standard wind resistance between two points is calculated according to formula (9): MT/T440--1995
Wherein: Raj--standard wind resistance between measuring points n and (n+1) under standard air density, N·s2/m. 5.7.3 Calculation of standard wind resistance per hundred meters in a tunnel
The standard wind resistance per hundred meters in a tunnel is calculated according to formula (10): 100
Wherein: Rmn---standard wind resistance per hundred meters in a tunnel, N·s?/m*,., distance between measuring points ij, m.
6 Processing of measurement results
（9）
(10）
6.1 Reliability check of measurement
When measuring the ventilation resistance of the selected measurement route, necessary Supplementary measurements are made to check the air volume balance and resistance balance of the ventilation network. At the same time, the error of the resistance measurement value of the whole mine is verified according to the relative static pressure measurement value and the natural wind pressure value in different wind conditions to determine the reliability. 6.2 Prepare a mine ventilation resistance measurement report
The report content mainly includes: measurement time, measurement purpose and requirements, ventilation and production conditions of the mine at that time, measurement route selection, personnel organization, instruments used, measurement methods, measurement results, mine ventilation resistance distribution, drawing of resistance distribution curves, and analysis and suggestions for improving mine ventilation conditions.
Measurement point number
Measurement point number
First time
At temperature
Second time
Wet temperaturebzxZ.net
MT/T440--1995
Appendix A
Example of data recording form
(reference)
tunnel parameter record table
tunnel specifications
Table A2 wind speed record table
speed, m/s
third time
cross-sectional area
average wind speed
atmospheric physical parameter record table
dry and wet temperature difference
relative humidity
atmospheric pressure
Instrument number
Air density
Measurement point number
Measurement point number
Measurement point number
Measurement location
MT/T440-1995
Table A4 "Differential pressure gauge pressure record table
Differential pressure gauge reading
Instrument correction coefficient
Table A5 Point-by-point measurement method barometer pressure record table Reading time|| tt||Reading difference
Pressure difference between measuring points
Static pressure difference between measuring points
Table A6 Barometer pressure measurement record table with dual measuring points simultaneous measurement method Reading
The 丨th unit
Number, Pa
The 丨th unit
Reading difference
Static pressure difference between measuring points
Instrument number:
Instrument number:
Instrument number:||tt ||MT/T440—1995
t/2$·N
pu/s·N
u/s·N
g/,s·N
Qu Mili
.u/sN
Additional Notes:
MT/T440-1995
This standard is proposed by the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the Ventilation Technology and Equipment Technical Committee of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. This standard is drafted by the Fushun Branch of the China Coal Research Institute. The drafter of this standard is Fu Kuiju.
This standard is entrusted to the Fushun Branch of the China Coal Research Institute for interpretation. 166
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