GAS TESTING REFRESHER COURSE

REFRESHER COURSE

1.0 HISTORY OF FLAME SAFETY LAMP
2.0 SAFETY FEATURES OF FLAME SAFETY LAMP
3.0 FUNCTION OF VARIOUS PARTS OF FLAME SAFETY LAMP
3.1 DETECTION OF GAS WITH FLAME SAFETY LAMP
3.1.1 ACCUMULATION TEST
3.1.2 PERCENTAGE TEST
4.DESCRIPTION ABOUT METHANOMETER
5. CO DETECTOR
6.PRECAUSTION AGAINST INFLAMMABLE & NOXIOUS GAS
7.CLASSIFICATION OF COAL SEAM INTO IT’S DEGREENESS
8. TABLE OF MINE GASES & THEIR MEASURING INSTRUMENT
9.MINE GASES & THEIR PHYSIOLOGICAL EFFECTS
10.DIFFERENCE BETWEEN IGNITION & EXPLOSION
11.DIFFERENCE BETWEEN INFLAMMABILITY & LAG ON IGNITION
12. IGNITION, CROSSING POINT TEMPERATURE
13. METHANOMETER OPERATING PRINCIPLE
14. DESCRIPTION OF MINE GASES-CO,CO2,SO2,NOx,H2Ss

What purpose the following parts of Flame safety lamp serve?
Wire gauge, Asbestos packing, Bonnet, Deflector ring, Magnetic
lock
Wire gauge: It allows the air to pass & distributes the heat and does not
allow the inflammable gas to burn out side the gauge.
Asbestos packing: It protects the flame from coming out of the lamp by
providing a seal in between both the ends of the glass.
Bonnet: Protects the lamp from mechanical damage and flame from blowing
air.
Deflector ring: It allows the intake air to go to the cap and not allows it to
move up (bottom feed)
Magnetic lock: Protects the lamp from intentional and inadvertent opening.


In spite of the availability of so many modern instruments
why still Safety lamp is used in underground mines?
1. Flame never betrays, where as electrical or electronic
apparatus may betray.
2. Instant reaction during Oxygen deficiency
3. No periodical calibration is required
4. Simple to operate, dismantle, and testing at all places
5. It can be used for continuous monitoring
6. All most zero maintenance cost
7. The lamp is most reliable, safest and dependable than any
other gas detectors.

Procedure for checking of Gas with Safety lamp.
First Step: Examine the lamp and make sure that it is properly
assembled and safe in all respects.
Accumulation test:-
-The purpose of this test is to ascertain if there is any accumulation
of gas in places where it is likely to accumulate.
-At first switch off the cap lamp.
-Raise the FSL cautiously with normal size flame.
-Watch its behavior carefully.
-If it elongates spires or jumps the percentage of gas can be taken
as 3% or more.
-No efforts should be made to raise the FSL higher than is
necessary to test for accumulation (the richer mixture may explode
inside the lamp or may burn inside the lamp) which may be
dangerous also the lamp may go off.
-If by chance firedamp begins to burn within the gauze, the
examiner shall shelter his lamp from the air current, hold it
near the floor and retreat carefully to the fresh air.
-If it is not possible, he should smother out the flame by
covering the air inlet holes or submerge the lamp in water if
available near by.
-It is unnecessary to conduct the percentage test if the gas is
detected in the accumulation test.

Percentage test :-
If in accumulation test gas is not observed than we go for
percentage test.

To conduct percentage test for methane with FSL
remove all bright light in the vicinity.

- Switch off the cap lamp.
-Lower the flame of the FSL with the regulating
knob till testing flame is made . This should be
done at a safe place free from gas but not too
far where percentage test should be conducted.
-Move slowly in a zigzag way, keeping eyes
normal to the testing flame. If gas is present
the gas burns with a non-luminous flame, which
varies in height depending upon the percentage
of the gas.

MSA D-6 Methanometer: It is used for checking Methane gas
-It is suitable for spot checking .
-Its measurement range is from 0 to 5 % by volume.
-A telescopic probe is provided for taking gas samples near the
roof or other inaccessible points
-The two section telescopic probe extends from 76 cm to 1.42
m.
-Rechargeable batteries are used in the methanometer
-Two nickel cadmium batteries are connected in series and
provide 2.2 to 2.6 volt for operation.
-Capacity of power pack is 1.2 AH
-A fully charged battery lasts for nearly 1000 ten-sec readings.
-Complete charging of battery takes nearly 14 hours
-Its weight is 470 g ( including the battery)


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COURTESY- Nitin B. Saxena WCL (HRD)

07-02-2020    0