AQ 6206-2006Coal mine high-low concentration methane transducer (English PDF)

3.1 Displayed value

Measured numerical value displayed on transducer.

3.2 Zero point

Value displayed on transducer which operates normally in clean air.

3.3 Calibration point

Standard gas sample value selected for transducer to meet measuring accuracy.

3.4 Alarm point

Alarm actuation value preset for transducer according to application requirement.

3.5 Basic error

Transducer measurement error value determined under normal test conditions.

3.6 Stability

Performances of transducer to maintain its zero point, calibration point and alarm point within

allowed variation ranges within specified operating conditions and time.

3.7 response time T90

Time required for transducer output to reach 90% stabilized value when methane concentration

shows step change.

4.1 General Requirements

4.1.1 Transducers shall meet requirements provided herein and be manufactured according to

specified procedure and drawings and technical documents approved by a state-authorized

inspection agency.

4.1.2 Transducer outfitting with associated equipment shall be qualified by an anti-explosion

inspection agency authorized by a competent authority. Equipment associated with transducers

shall carry mining product safety certificate with validity.

4.1.3 Transducer anti-explosion type shall be mining intrinsic safety and explosion suppression

type, marked with "ExibdI".

4.2 Operating Conditions

Temperature. (0-40) oC;

Relative humidity. <=98%;

Atmospheric pressure. (80-116) kPa;

Wind speed. not more than 8 m/s.

4.3 Storage Temperature. (-40-60) oC.

4.4 Output Signal Types

Following signal types should be used.

a) Current type. DC (1-5) mA, (4-20) mA;

b) Frequency type. (200-1,000) Hz (pulse width more than 0.3ms), (200-2,000) Hz;

c) Digital signal type. transmission rate 1,200bps, 2,400 bps, 4,800 bps, 9,600 bps, not lower than

3V.

4.5 Requirements for Transducer Appearance and Structure

4.5.1 Transducer display window shall have good light transparence, numbers and symbols shall

be legible and complete.

4.5.2 Transducer surface, plating or coating shall be free of air bubble, crack, obvious flake-off or

stain.

4.5.3 Transducers shall be structure-reasonable, firm and durable, with suspension or support

calibration specified in enterprise product standard (known as specified flow rate for short).

Connect transducer to regulated power supply, respectively adjust regulated power supply output

to max and min operating voltage specified in enterprise product standard, and determine stability

of displayed value on transducer and basic error.

5.3.1 Stability of Displayed Value

5.3.1.1 Low Concentration Range

After transducer zero point is stabilized in clean air, supply specified flow rate of 2.0%CH4

standard gas sample for 3 minutes, adjust transducer displayed value to accord with standard gas

sample value, continue to supply gas, observe for 1 minute more, record difference between max

transducer displayed value and min transducer display value, repeat the tests for 3 times and take

the max difference.

5.3.1.2 High Concentration Range

After transducer zero point is stabilized in clean air, supply specified flow rate of 20%CH4

standard gas sample for 3 minutes, adjust transducer display value to accord with standard gas

sample value, continue to supply gas, observe for 1 minute more, record difference between max

transducer display value and min transducer display value, repeat the tests for 3 times and take the

max difference.

5.3.2 Basic Error

5.3.2.1 Low Concentration Range

Calibrate transducer 3 times by using specified flow rate, clean air and 2.0%CH4 standard sample

(known as instrument calibration). No re-calibration is allowed in subsequent tests.

After transducer zero point is stabilized in clean air, supply specified flow rate of 0.5%CH4,

1.5%CH4 and 3.5%CH4 standard gas sample in turn respectively for 3 minutes, and record

transducer display value or output signal value (converted to methane concentration value).

Repeat measurement for 4 times and take the difference between arithmetic mean value of the last

5.3.2.2 High Concentration Range

Calibrate transducer 3 times by using specified flow rate, clean air and 20%CH4 standard sample

d) Anti-explosion certificate number;

e) Coalmine safety mark number;

f) Metering tool manufacture license number;

g) Model of associated equipment;

h) Major technical parameters;

i) Protection class;

j) Manufacturer's name;

k) Exit-factory serial number and date.

7.1.3 Package Marks.

a) Shipment marks shall meet related transportation rules;

b) Handling marks shall meet GB 191 requirements.

7.2 Package

7.2.1 Package shall be of composite protection type, rain-prof, moist-proof, dust-proof and

vibration-proof.

7.2.2 Following documents shall be put into packing boxes.

a) Product certificate;

b) Product operating instruction book;

c) Packing list.

7.3 Operating Instruction Book

Operating instruction book shall be written according to GB 9969.1-1998.

7.4 Transportation

Well-packed products shall be suitable for highway, railway, and waterway and airway

transportation.

7.5 Storage

Products shall be stored in a storehouse well-ventilated and free of corrosive gas.

References and Original Chinese Documents

[1] AQ 6206-2006 Coal mine high-low...

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