AIM OF THE EXPERIMENT: Determination of Percentage of CO and CO2 by

Drager Multi Gas Detector (Model : 21/31)

APPLICATION:- Determination of percentage of CO and CO2 in Mine air, for

technical gas analysis and also used in the Industrial Plants and the Areas where CO
and CO2 are likely to be occurred.

PRINCIPLE:--The reaction of CO and CO2 with the chemicals present in the

detector tubes change their color and the extension of the discoloration is the
percentage, directly read off from the detector tube.

CONSTRUCTION:- (Ref. fig.)The two essential components of the Drager Multi Gas
Detector are the Gas Detector Pump (also called the Bellow Pump) and Drager Tube
chosen as a function of the measurement to be carried out. The Bellow Pump
simultaneously sucks in and measures the gas volume. It sucks in 100 cm3 of air per
stroke.

Sucking in the Gas sample (principle): When the Bellow Pump is compressed
the air in it escapes through the Outlet Valve and not through the Tube, since the
tube has a much higher resistance than the Outlet Valve. The pump suction
operation commences when the fingers are relaxed. The Compression Springs inside
the bellows which are place under stress when the bellows is compressed extend and
Outlet Valve is closed through the vacuum created in the bellows. The air flows
through the Drager Tube into the bellows while the latter returns to the original
volume. The end of the suction movement is reached when the Limit Chain is
completely taut.

Drager Tube:
A.Carbon Monoxide detector Tube: The tube is inserted into the Pump head
which has an aperture for the test purpose.
Chemicals contain:
1. White indicating layer of Iodine Pent oxide, Selenium dioxide and
Fuming sulphuric acid which turns into brownish green in the presence of CO.
5 CO + I2O5 I2+5CO2 (Turns to Brownish color)

2. Precleanising layer of Guard Chemical: A chromium compound to

Remove water vapor, gasoline vapor, Hydrogen sulphide and
Nitrogen dioxide which interfere with CO% reading.
And also a pre-tube of activated charcoal is inserted into the detector
tube to remove high concentration of Hydrogen gases.
Range of Measurement:
With n= 1 stroke, 0.01 to 0.3% by volume of CO
With n= 10 strokes, 0.001 to 0.03% by volume of CO.
With n= 5 strokes, up-to 0.06% by volume of CO
And the evolution is made on 10-stroke scale, multiplying the
Numerical value with the factor 2, this results in % by volume of CO.

Measurement: The total length of discoloration is the measure of the CO

concentration by volume of CO in %.

B. Drager Tube (CO2) :

Chemicals contains: A pre-cleansing layer and a white indicating layer of the
chemical i.e. Hydrazine ( NH2NH2) , which changes color to bluish-violate due to
reaction with CO2.
Measuring Range:
With n= 10 strokes, 0.01 to 0.3% by volume of CO2.
Measurement: The total length of violate discoloration correspondence
to the concentration in % by volume of CO2.

TEST PROCEDURE

 Check the pumps for leaks before each series of measurements.

 Break off both tips of the Drager Tube in the break off eyelet or ( the break
off husk provided with the instrument).
 Tightly insert the Drager Tube in the pump head with the arrow pointing
towards the pump.
 Hold the pump in the hand with the pump between the thumb and the base
of the index finger and the fingers resting on the front plate.
 Fully compress the Bellows.
 Straighten the fingers. The suction process takes place automatically and is
completed when the limit chain it taut.(It takes 15-25 sec. for one stroke)
 Repeat the suction process as often as specified in the Tube operating
instructions.
 Find out the length of the discoloration as described in the Tube operating
instruction and thus the % of the gas (CO or CO2 ) .
OBSERVATION:

Sl. No. Concentration value Remarks

(PPM / % by volume)
1 2800 ppm (CO) Exhaust of Honda Shine Bike
2 1.9 % (CO2) Do
 AIM OF THE EXPERIMENT: Determination of the Carbon monoxide in
Air or in Industrial gases using MSA-AUER GAS TESTER.
General Description:
The MSA -AUER GAS TESTER/Thumb pump sampler in combination with
detector tubes is used to measure the concentration of hazardous gases and vapors
in air or technical gases. a sample is collected by attaching the doctor tube to a
special suction ball pump that draws a known volume of air with each stoke
characteristic color stain is formed for each type of detector tube when the
appropriate number of pump strokes are performed. The length of this stain
indicates the concentration of the hazardous substance.
Detector tubes are particularly useful in situation in which quick screening is
required. Such as Haz-Mat response and for use in various industries in which
specific, routine groups of compounds are monitored regularly.
Design/Construction(See Fig.)
The MSA -AUER GAS TESTER/Thumb pump sampler is a suction ball-type
detector tube pump. compressing the suction ball and inflating will sample a
volume of 100 ml(volume per pump stroke) on the inserted detector tube tightly.
Operation:
1.Check for Aspirator Performance and Tightness:
Compress pump without inserting a detector tube and release expansion stroke.
Suction ball must be completely expanded within 2 seconds. If the time to expand
exceeds this value. Check bushing And pump body for clogs.
Insert a sealed detector tube into pump body and compress the suction ball. The
measuring device is sufficiently tight, when the suction ball has not completely
expanded within 15 minutes.
2. Opening of the detector tube:
Break off both tube tips using the tube breaker.
3. Inserting the detector tube:
Insert the detector tube with slight pressure tightly into the pump body. The arrow
on the detector tube must point toward the Gas -Tester.
4. Set Disc Counting Device:
Before stating the measurement, set disc counting device to the number given in
the instructions for use of the detector tube used. The disc counting device is
turned by one digit for each stoke.
5. Actuate Pump:
Compress operating ring of suction ball in the direction of the pump body up to the
stop on intended location.
Do not try to squeeze out the residual air contained in the sides of the suction ball.
Take off thumb and allow suction ball to expand freely.
After the suction ball has expanded, Keep the detector tube for another 5 second
(minimum) in the sampling area
Repeat sampling procedure compressing and expanding as often as indicated in the
Instructions for use.
Move the disc counting device on by one digit every pump stroke. Evaluate
detector tube reading as described in the instruction for use.
6.The white Portion changes into light green.
7. Flushing:
After each measurement flush Gas –Tester with several blank stroke(without
detector tube).
Smoke may be emitted depending on the detector tube used.
Technical Data:
Aspiration volume per stroke :100ml
Aspiration Period: Depending on relative to 1 stroke detector tube flow resistance
Weight-ca.120g
Length:148mm
Max.diameter:68mm
Materials: Rubber, Polypropylene.

Observation Table:

SL. NO. Number Of concentration Remarks

Stroke
1 One >1000ppm Honda Shine Bike
2 One 950ppm Honda scooty
Aim of the Experiment: Determination of Methane % in Mine Air by
MSA D-6 Methanometer

APPLICATION: MSA D-6 Methanometer is a very handy and a spot detecting

instrument with measuring range from 0 to 5% Methane by volume. It is approved by
D.G.M.S to be used in underground coal Mines.

PRINCIPLE: (Catalytic combustion) The apparatus utilizes the principle that the
resistance of a wire increases on heating by combustion of methane. The heat produced
by the catalytic combustion of the Methane gas, present in a sample of mine air ,when
in contact with the detecting filament causes a proportional change in its electrical
resistance, thus unbalancing a balanced Wheat-stone Bridge by passing a current
through the galvanometer. The amount of current flow is related with the percentage of
Methane in air and is read off from the indicating meter (galvanometer) which is
calibrated accordingly.

CONSTRUCTION: (Ref.fig.) The instrument is housed in an impact resistant anti-static

plastic case. It comprises of the following components:

Diffusion Head: Ambient air reaches the sampling chamber of the Methanometer by
natural diffusion through Diffusion Head. It is protected by sintered metal filter and a
dust cover.

Balanced Wheat-stone Bridge: It comprises of two identical platinum filaments (i)

Activated platinum (detector) (ii) Deactivated platinum (compensator) and two
resistors forming the four-arm of the balanced wheat stone bridge. Air sample is
drawn in the detector and compensatory chamber by an aspirator bulb or by natural
diffusion. When mine air containing firedamp is drawn only detector filament
resistance is changed due to burning of methane.

Methane Indicator: A graduated Galvanometer to read the Methane % and the red zone
on it for rapid battery checking.

Flashback arrestor:-There are two flashback arrestors provided on both sides of the
detector filament so that Methanometer igniting the sample external
to the device is restricted.

Battery: Sealed Ni-Cd rechargeable battery, Avg. voltage: 2.5 volt, Final Voltage: 2.2
volt, Capacity(10 hours rate): 1.2 Ah. A fully charged battery can last for about 500 tests.

Push Button: 2 nos. One for measuring Methane %, the other one for battery checking.

Charging terminal: Situated on the outside of the Methanometer casing for recharging
of the battery.
ACCESSORIES: A telescopic probe of nearly 1.48 meter extended length and an
aspirator bulb for the atmosphere to be analyzed which is beyond reach. The air enters
through the four side holes at the end of the probe.

TEST PROCEDURE:
Without the Telescopic Probe Rod:
 Check the battery condition by pressing the methane check button. The pointer
should lie in the red zone indicating a voltage of 2.2 to 2.8.
 Hold the instrument at the spot to be measured, open the Dust Cap and wait for a
few seconds.
 Press the methane check button.(10 to 15 seconds)
 Wait the needle to be stabilized.
 Read the methane % on the meter.
 Release then the button.

With the Telescopic Probe:

 Check the battery condition by pressing the methane check button. The pointer
should lie in the red zone indicating a voltage of 2.2 to 2.8.
 Open the dust cover over the diffusion head.
 Screw the threaded socket of the probe (lower end) firmly to the diffusion head.

 With the probe end in place, squeeze the aspirator bulb 2-3 times.
 Wait for 2 seconds and press the measuring button.
 Read the % on the meter after the needle is stabilized.
 Release then the button.
TEST PROCEDURE IN LAB:

As methane gas has similar properties with LPG the % of methane is tested in a gas
testing chamber. The LPG gas is passed to the chamber with a regulated manner and
the cited procedure is adopted to know the methane %.
OBSERVATION:
SL Name of the Inst. % of Methane Remarks
No.
1 MSA D-6 Methanometer 3.3
2 Do 2.5

Technical data:
Weight: 470 g. (Including battery)
Measuring range: 0-5% Methane.
Accuracy: ± 0.1%
Battery: Avg. voltage: 2.5 volt, Final Voltage: 2.2 volt, Capacity(10 hours rate): 1.2 Ah.

Battery life : 500 Ten-seconds reading approximately when fully charged.

Charging hours: 14 hours
Time taken for the operation: 1.5 -2 minutes
AIM OF THE EXPERIMENT: Determination of Relative Humidity of Mine air By

(1).Fixed/stationary Hygrometer (2) Whirling Hygrometer

Application: The Hygrometer is an instrument by which Relative humidity of air i.e. the
extent to which it is saturated with moisture can be determined.

Concept: Humidity is a specification of the amount of water vapour contained in air.

Under natural conditions, air is never completely dry and It’s degree of wetness is
called Relative Humidity or in other term
R.H.= Mass of water vapour present in 1m3 of air /
Mass of water vapour required to saturate 1 m3 of air at the temperature of observation.

If a man is working in an atmosphere which is completely saturated with moisture, since

the air can accept no more moisture, evaporation of sweat and hence body-cooling
becomes impossible, and the body temperature will rise with serious physological
effects. It is also important the air in contact with a sweating body should be removed
as it becomes saturated and replaced by dry air. Therefore humidity in mine air is
required to be known to determine the comfortless and efficiency of workers.
Effects of humidity:
It decreases the physical working efficiency of the workers.
It causes mental fatigue.
It has negative effect on cardiovascular systems.
Water and chloride metabolism takes place.
The Hygrometer consists of a Dry bulb and a Wet bulb Thermometer mounted side by
side in a suitable frame. The air is forced past the bulbs (aspirated or ventilated
psycrometer), or the bulbs are whirled (whirling hygrometer) or may be simply faced to
an air current(fixed hygrometer) to achieve evaporation and subsequent cooling of the
wet bulb. The amount of evaporation and subsequent cooling of the wet bulb
thermometer ,depends on the humidity of the atmosphere, the drier the atmosphere ,the
faster the water evaporates. Using the data and humidity table, psycrometeric chart,or
calculation ,the relative humidity can be determined. The dry bulb indicates the actual
temperature of the surrounding air, while the wet bulb thermometer in conjunction with
the dry bulb thermometer indicates the degree of saturation of the air (i.e. R.H.).

FIXED HYGROMETER:----- The fixed or non-ventilated hygrometer consist of two

thermometers mounted side by side. The bulb of one is exposed to air, that of the other
covered with thin muslin cloth, the lower end of which is dipped into a container filled
with distilled or rain water. The surface of the muslin cloth should be clean and is
essential to change it in time to time. Care should be taken to wipe out all the dirt and
moistures from the surface of the dry bulb when taking reading. After taking readings
in underground mine air the R.H. can be found out from the psychrometric chart , from
the standard psychrometric table provided by the manufacturer or from the formulas.
The hygrometer is placed at an air current of 3m/s for at least one minute and then the
thermometer readings are taken quickly. From the readings the relative humidity is
determined.
DEMERITS: Unless the fixed hygrometer is placed in an air current with a velocity of
3m/s or more ,the moisture evaporated from the wet bulb surrounds both the dry and
wet bulbs ,thus affecting the reading slightly. Besides , the evaporative cooling of the
wet- bulb may also affect the dry -bulb temperature with low air velocity.

WHIRLING HYGROMETER:-The It is also known as Sling Psychrometer, similar in

principle to the ordinary wet and dry bulb hygrometer, but the thermometers are
mounted side by side on a brass frame fitted with a handle for whirling purpose. In use,
a muslin cloth is placed around the wet bulb, and the bulb is dipped into a bottle of
distilled water to saturate the muslin cloth. The demerits of fixed hygrometer are
overcome by using this type of hygrometer. The hygrometer is whirled at 200rpm
(which produces a relative air velocity of 3m/s.) for about a minute, and then the
thermometer readings are taken quickly, but the wet bulb reading is taken first. It must
be repeated until two consecutive readings are same. During whirling, the hygrometer
should be shielded from solar radiation and held as far from the body as possible, with
the hygrometer facing the path of air current. Though it is difficult to ensure any
consistency of speed, for certainty in any working requiring any accuracy, the wet bulb
should be ventilated at an adequate rate (2.5m/sec.), and whirling rate should be about
200 rpm.

Relative humidity of mine air in the temperature range obtained in Indian mines can be
roughly calculated as follows:

1. R.H.= 100 –7{ dry bulb temp. (D.B.T.) – wet bulb temp. (W.B.T.)}
For D.B.T. > 25° centigrade
2. R.H.= 100 – 8{ dry bulb temp. (D.B.T.) – wet bulb temp. (W.B.T.)}
For D.B.T. in between 20-25° centigrade
3. R.H.= 100 – 9{ dry bulb temp. (D.B.T.) – wet bulb temp. (W.B.T.)}
For D.B.T. < 20° centigrade
Observation and calculation:

SL Hygrome DBT(Dry bulb WBT(Wet R.H. Remarks

. -ter temp.) bulb temp.) (from the
No Psychro-
metric
Table
1 Fixed 20 15 56% Inside the
type Lab.
2 Whirling 20 15 56% Do
type
3 Calculati 20 15 60% Do
-on
Precautions:
1.While taking readings in underground mines the cap lamp should not be close to the
Hygrometer, so that heat given out by it does not affect the thermometer operation.
2. Care should be taken to wipe out all dirt and moisture from the surface of the dry bulb.
3.The surface of the muslin cloth covering the wet bulb should be clean and should be
changed time to time.
4.As per as possible the fixed hygrometer should be placed in an air current with a
velocity of 3 m/sec.
5.Dusty conditions in a coal mines is undesirable.
AIM OF THE EXPERIMENT: Determination of Relative Humidity of air using Assman
Psychrometer (Model : SIBATA,Japan)

Application: The Assman Psychrometer is an instrument commonly used to determine

the Relative Humidity of atmospheric air based on the precision readings of
temperature of the wet bulb thermometer and dry bulb thermometer

Principle: The instrument is based on thermodynamics principle.

Construction: This is an aspiration psychrometer with the bulb of thermometer ventilated
by a fan, which is operated by a clock spring. The clock spring functions by a key
provided by an instrument. A suction fan pulls air at the rate of approximately
180m/min. The thermometers are protected from direct solar radiation by double-
walled shields where outer surfaces are bright chromium plated and are insulated to
prevent heat transfer from the metal case of the bulbs. The wet bulb is supplied with a
gauge wick. An injector is provided for moistening the wet bulb with distilled water.
By reading the difference of degrees between the two thermometers humidity can be
measured according to the humidity table supplied with the instrument.
Accessories: (1)A tripod with a suspender
(2)A wind protector (a semi circular ring which is fitted with the head that covers half
portion of the head)
Range: 30° – 50° centigrade
Least count: 0.02° centigrade
Procedure:
Before taking a reading, distilled water / rainwater is applied to the moistening sleeve of
the wet bulb by the pippet and should be ensure that the muslin sleeve is actually
soaked with water.
Where the reading is to be taken the psychrometer is hung with the help of the suspender.
Then the spring of the aspirator is wound by inserting the key into the keyhole and
turning it clockwise. The key can remain in its aperture, as its projecting rim prevents
rain and dust from penetrating into the clockwork.
The fan is allowed to rotate atleast 3 minutes to run constant speed to avoid the wind
effect.
If the psychrometer is used in a place where the wind speed is comparatively high , the
wind protector protects the air inlet hole of the head.
The wet bulb temperature is first taken and then the dry bulb temperature.

Observation and calculation:

Least count = 0.02° centigrade
t = dry bulb temp.
t1=
wet bulb temp.
Difference between the temp. of the bulbs = t1 – t
Then the Relative Humidity is found out by the humidity table supplied with the
instrument.
Precautions:
It should be taken into account that the temp. of the instrument itself most confirm to the
ambient temp., before a reading can be taken at any rate, the first reading should not be
taken before the aspirator has been running for atleast 3 minutes. By taking several
consecutive readings it can immediately be ascertained whether or not the measuring
results still varies. In case there are essential differences between the ambient temp. and
the temp. of the instrument, a final reading will usually be obtained after approximately
5 minutes.
Continuos measurements require that the clockwork is entirely wound-up a new, before
the interval is passed which is stated as “Defective running time.” .
The moistening sleeve of the wet bulb thermometer should be frequently changed, if high
temperatures are to be measured.

Observation and calculation:

SL. DBT(Dry bulb WBT(Wet bulb R.H. Remarks

No temp.) temp.) (from the
Psychro-
metric
Table
1 19 14 56% Inside the
Lab.
AIM OF THE EXPERIMENT: Determination of Relative Humidity of air
using Assman Psychrometer (Model : SIBATA, Japan)

Application: The Assman Psychrometer is an instrument commonly used to determine

the Relative Humidity of atmospheric air based on the precision readings of
temperature of the wet bulb thermometer and dry bulb thermometer

Principle: The instrument is based on thermodynamics principle.

Construction: This is an aspiration psychrometer with the bulb of thermometer ventilated
by a fan, which is operated by a clock spring. The clock spring functions by a key
provided by an instrument. A suction fan pulls air at the rate of approximately
180m/min. The thermometers are protected from direct solar radiation by double-
walled shields where outer surfaces are bright chromium plated and are insulated to
prevent heat transfer from the metal case of the bulbs. The wet bulb is supplied with a
gauge wick. An injector is provided for moistening the wet bulb with distilled water.
By reading the difference of degrees between the two thermometers humidity can be
measured according to the humidity table supplied with the instrument.
Accessories: (1)A tripod with a suspender
(2)A wind protector (a semi circular ring which is fitted with the head that covers half
portion of the head)
Range: 30° – 50° centigrade
Least count: 0.02° centigrade
Procedure:
Before taking a reading, distilled water / rainwater is applied to the moistening sleeve of
the wet bulb by the pipette and should be ensure that the muslin sleeve is actually
soaked with water.
Where the reading is to be taken the psychrometer is hung with the help of the suspender.
Then the spring of the aspirator is wound by inserting the key into the keyhole and
turning it clockwise. The key can remain in its aperture, as its projecting rim prevents
rain and dust from penetrating into the clockwork.
The fan is allowed to rotate at least 3 minutes to run constant speed to avoid the wind
effect.
If the psychrometer is used in a place where the wind speed is comparatively high , the
wind protector protects the air inlet hole of the head.
The wet bulb temperature is first taken and then the dry bulb temperature.

Observation and calculation:

Least count = 0.02° centigrade
t = dry bulb temp.
t1=
wet bulb temp.
Difference between the temp. of the bulbs = t1 – t
Then the Relative Humidity is found out by the humidity table supplied with the
instrument.
Precautions:
It should be taken into account that the temp. of the instrument itself most confirm to the
ambient temp., before a reading can be taken at any rate, the first reading should not be
taken before the aspirator has been running for atleast 3 minutes. By taking several
consecutive readings it can immediately be ascertained whether or not the measuring
results still varies. In case there are essential differences between the ambient temp. and
the temp. of the instrument, a final reading will usually be obtained after approximately
5 minutes.
Continuos measurements require that the clockwork is entirely wound-up a new, before
the interval is passed which is stated as “Defective running time.” .
The moistening sleeve of the wet bulb thermometer should be frequently changed, if high
temperatures are to be measured.

Observation and calculation:

SL. DBT WBT R.H. Remarks

No (Dry bulb temp.) (Wet bulb (from the Psychro-
temp.) metric Table provided
by manufacturer

1 19 14 56% Inside
theEnv.
Lab.
Aim of the Experiment: Study of Kata Thermometer & Determination
of Kata Cooling Power

THEORY: To judge whether a working place is suitable for a man to work efficiently
and without discomfort, it is necessary to know the temperature of air at the working
place, the relative humidity and air velocity. The joint effects of all these factors can be
known with the help of the Kata thermometer which answers the Cooling Power by
combination of the above mentioned three factors at the instrument temperature of
36.5º C, the normal temperature of the human body.

DESCRIPTION OF THE UNIT: ( Ref. Fig.)The Kata thermometer consists of an

Alcohol Thermometer with a large bulb of 4 cm long and 2 cm in diameter and a long
stem 20 cm long graduated only at two points namely 38º C and 35º C having two
smaller bulbs at the top and at the bottom of the stem.

PROCEDURE: The Alcohol bulb is immersed in hot water carried in a thermos flask
until the alcohol rises to the top reservoir. The bulb is wiped dry and time taken for the
alcohol column to fall from the upper mark to the lower mark is noted. The procedure is
repeated with a wet muslin cloth wrapped on the bulb.
An instrument factor is marked on every instrument. The Kata Factor of an instrument
is the number of mill calories of heat which it loses per cm2 of the surface area of the
bulb on cooling from 38º C to 35º C.

Kata Cooling power (mill calories / cm2 /second) = Kata Factor

Time in seconds for alcohol to fall from upper mark to lower mark
.
The cooling power calculated is called dry if no wet cloth is used on the bulb and wet, if
wet cloth is used. The cooling power is given in mill calories per sq.cm. per second and
it is the relative value that is important. If the dry kata is used , the result is the cooling
power by radiation and convection. So it is of little importance particularly under hot
and humid conditions where most of the heat loss from the human body is through
evaporation. If the wet kata is used , the result is the cooling power by conduction
,convection and radiation. Minimum limits for the kata thermometer cooling power for
comfortable working are as follows:

Dry Kata Wet Kata

1. For sedentary workers – 6 18
2. For light manual workers – 8 25
3. For hard manual workers – 10 30

If the dry time is used, the result is the cooling power by Radiation and convection.
Cooling power by conduction, convection and radiation is given by the wet bulb time.

Cooling power Referred to WET Kata Reading

 Wet Kata Cooling Power Effect
Up to 5 Extremely Oppressive/harsh
5- 10 Oppressive
10-15 Lowest Value for Satisfactory Conditions.
20-25 Best Conditions for work
30 Feeling Of Chill unless well clothes
35 Uncomfortably cool
‘
Observation and Calculation:

SL.No. Kata Time taken from upper Kata Cooling Type of Kata Remarks
factor mark to lower Mark Power
(in Sec)
1 376 140 2.68 Dry Kata value
2 376 62.7 6 Wet Kata value Oppressive

Precautions:
Before dipping the thermometer into the hot water, it is to be ensured that the water is not
too hot, otherwise the glass thermometer may burst.
As soon as the alcohol reaches the top most point the thermometer should be taken out of
the hot water.

Drawback:i)The rate of cooling of Kata thermometer is much faster compared to human

body. it is because, the kata thermometer is much smaller compared to human body and
has a smaller volume to surface area ratio.
ii)The body surface is rarely completely sweat covered as the wet kata.Because of
clothing, air cannot get access to the whole body surface.

iii)The Kata Thermometer overestimates the effect of air velocity and under estimates
that of temperature and humidity of the mine air as regards of its cooling power.
AIM OF TEXPERIMENT: Measurement of Air Velocity by Electric Analog
Anemometer (MODEL: NMC)

Utility: Electric Analog Anemometer is a spot reading instrument which gives direct
reading of air speed. Leveling, time-measurement, calculations and time-consuming
conversions are not needed.

Description: The instrument is fitted in a briefcase. It consist of a

Sensing head
Indicator unit
Power supply unit
Switching unit
Power supply Indicator

Sensing Head: It consists a double pivoted Aluminum vane mounted in jeweled bearings
and a transducer in a Bakelite case. The transducer, which is non-optical, non-magnetic
and non-contact type that is un- affected by vibration, dust, temperature and humidity.
As the vane rotates the transducer generates electrical signals having the frequency
directly proportional to the velocity of the Air through the sensing head. These electrical
signals are then converted to direct current, which drives the pointer of the indicating
meter. It is having an extension cable with a polarized connector.

Indicating meter: Calibrated in m/sec = 198 ft/ min of air velocity. It is marked off from
0 – 5, each individual of 0.1. Battery checking facility is also available.
Power unit and power supply indicator: 6 batteries each of 1.5 v (medium size) are put
in the battery case. The terminals are connected to the power supply indicator for
power supply.

Switching unit:
Facilities for three positions:
1. X1 = for air velocities in between 0 – 5 m/sec
X2 = for air velocities in between 0 – 10 m/sec
X3 = for air velocities in between 0 – 15 m/sec
B = for battery checking
0 = for off position
Accuracy: ± 2%

It is claimed that there is no appreciable error in the reading of the velometer with an angle
 of Yaw up-to 30°. Air density affects the velometer readings slightly. A correction factor
which is universally proportional to the square root of the air density to be multiplied
with the reading to get the correct value where great accuracy is needed. Usually a
correction chart (density chart) is provided with the instrument.

Procedure:
• Open the box.
• Make the battery connections and the battery checking.
• Make the connection of the polarized connector of the extension cable to the input
socket.
• The sensing head is set at the point where air velocity is to found out.
• Turn the switch to X3 position, which gives the range of 0 – 15 m/sec. If the
velocity is < 10 m/sec turn to position X2, if velocity is in between 0 – 5 m/sec
turn to X1 position.
• Find out the velocity of the Air.

If the switch is in X3 position multiplied the reading by 3.

If the switch is in X2 position multiplied the reading by 2.
And the result is multiplied by the correction factor if more accuracy is needed.
• Then turn switch off position.
.
Observation & Calculation:
Sl Instrument Distance
No From
Window
Ac (in Velocity(m/s)
meter)
01 Electric 1 5.2
Analog
Anemometer
2 3.5

Precautions: While taking readings in an underground roadway following precautions

are to be taken
Angle of Yaw should not be greater than 30°.
The head should be away from bends, junctions and places having sudden changes in
cross-section.
The roadway where measurement is taken should have nearly uniform cross-section for
15 m on either side and away from bends and junctions .
The sensing head should be away from the body of the observer; i.e. the body should not
block the instrument head.
AIM OF THE EXPERIMENT: Measurement of Air Velocity by Vane
Anemometer (Biram Type)

Range of Application: Control of air streams in heating, ventilating and air conditioning
systems, cold storage rooms and drying cleans, measurement of air velocities in
underground mines, and measurement of air velocities of directed air stream as in
piping and channels.

Construction: The Vane Anemometer is an instrument to determine the distance traveled

by air in a given time. It consist of a small fan or air turbine set at an angle of 40°.-45°
to the direction of air flow which rotates the vane at a speed proportional to the air
velocity. The shaft or spindle actuates through gearing a series of pointers on the dial
face of the meter, so indicating the distance in meter traveled by air in a given time. A
clutch is fitted to be put in or out of gear as required. The zero reset arrangement is also
provided with the instrument.

Specification: Vane Anemometer (Biram Type) made in Japan

Range: 0 – 100000 m

Possible measuring wind speed: 1-15 m per second

Number of Dials: 4 nos.

The large dial is marked off into 100 divisions each representing 1 m of air travel. The
smaller dials are marked off into 10 divisions.

Procedure to determine air velocity in a gallery:

To determine the Air Velocity in under-ground mine a Stop watch and the Instrument
itself is essential.

Care is to be taken in the selection of site for air velocity measurement. The airway
should have uniform cross-section for nearly 15 m on either side and should be straight
and away from curves, bends and junctions.
Suitable methods of velocity measurement is selected.(i.e. Single point measurement,
Continuous traversing or Precise traversing)
The cross-section of the roadway is divided into small rectangular section (preferably
squares) by stretched wires incase of Precise traversing.
➢The instrument is set to zero-zero with resetting device.
➢The instrument is held in the hand and kept fixed perpendicular to the air velocity (i.e.
the direction of air flow and fan most formed right angle). For precise work it should be
held at the end of a stick or rod to reduce the effect of the hand, arm and body on the air
stream. The observer should stand at-least 1.5m on the down stream side of the station.
Provisions can be made for mounting the Anemometer on a shaft with a string to
 operate the clutch for more accurate measurement .keeping away the body.The angle
of yaw should be maintained below 10°.
➢The stop watch is kept ready.
➢The gears of the dials are engaged by the clutch and simultaneously the stop watch is
made for running.
➢The distance traveled by air is then observed in the particular time. At the time of note
the instrument is de-clutched and simultaneously the running of stop watch is also
stopped.

The difference in the dial positions gives the distance traveled by air in that particular
time. The reading should be corrected by referring the correction table supplied by the
manufacturer.

Observation and calculation:

Sl. Instrument Distance D (in T (in Velocity

No. From meter) sec.) (m/s)
Blower (in
meter)
01 Vane 1m 742 120 6.18
Anemometer
2m 521 120 4.34
* D =distance traveled by air(in meter), T = time taken to cover the distance(in sec)

Velocity of air current for each station is determined separately and average velocity is
found out.
Alternately the observer may move the instrument slowly over the area vertically up and
down or horizontally in case of Continuous Traversing.

*Correction table for internal friction of Anemometer

Reading m/s Coefficient

5 0.98
5-10 1.0
10-15 1.01
Aim of the Experiment: Measurement of Respirable Dust concentration
by PM10 Sampler
(Model: Envirotech APM 460NL)

Application:-For obtaining samples of respirable fraction of air borne dust ( i. e. PM 10

particles ) in Mines and other locations and which can be operated unattended for a full
working shift/for 24 hours.

Theory: High Volume Air Samplers are designed for monitoring the Total Suspended
Particulates (TSP) in ambient air. The coarser dust collected as a part of TSP would
result in nuisance, soiling of surfaces and perhaps some visibility problems but is
unlikely to contribute significantly to respiratory and other health effects associated
with air pollution. Health effects are caused primarily by respirable particulates in the
size range of 0.3 to 10 microns. As such the main objective in Ambient Air Quality
monitoring is to protect the local community; measurement of TSP alone may often be
misleading. So, Now a days, Air monitoring Programmes are increasingly adopting the
use of Respirable Dust Samplers in preference to the traditional TSP samplers.
The Respirable dust standard adopted by the Central Pollution Control Board
recommends a 10 micron cut off size for respirable dust measurements. The cyclone of
the APM 460 NL Respirable Dust Sampler has been designed to provide a cut off at 10
microns for particulates commonly found in the urban environment.

Principle: The APM 460 sampler uses an improved cyclone with sharper cutoff-D 50 at
10 microns to separate the coarser particles(>10microns) from the air stream before
filtering it on the glass microfiber filter.PM 10 dust is accumulated on the filter paper
while courser dust particles(>10microns) is collected in a cup placed under the cyclone.

APM 460NL Dust Sampler is recommended for use in the Indian Mines, manufactured
by Envirotech, New Delhi. It is a fixed point instrument comprising of:

(Ref.fig.):

AIR INLET PIPE: Ambient Air laden with suspended particulates enter the system through
the inlet pipe. The air inlet pipe is attached to the cyclone inlet by four socket head
screws. It is connected to an inlet cover cap on the top of the inlet pipe.

Cyclone:- As the air passes through the cyclone, coarse, non-respirable dust is separated
from the air stream by centrifugal forces acting on the solid particles. These separated
particles fall through the cyclone’s conical hopper and collected in the sampling bottle
placed at its bottom. The fine dust forming the respirable fraction of the total suspended
Particulate (TSP)passes through the cyclone and is carried by the air stream to the filter
paper clamped between the top cover and filter adopter assembly. The respirable dust
is retained by the filter and the carrier air is exhausted from the system throw the
blower. The Cyclone cup is set at the bottom of cyclone to collect larger size particle
those do not retain in the Air stream.
HEAVY DUTY BLOWER:- It is driven by continuous duty, Brushless induction motor which
draws in air through inlet, cyclone and filter. It is run by AC motor which ultimately
run by 220V,Single phase AC supply. It is located at the bottom side of the cabinet.

ORIFICE METER: It is really a manometer assembly used to measure the pressure drop
across an orifice plate built into the filter adapter casting and its scale is graduated to
read directly the flow rate of air in meter cube per minute. The pressure drop across the
orifice plate is calibrated in terms of air flow in m3/minute. The manometer uses
distilled water as manometer fluid which must be topped up from time to time. The
brass screw mounted on the meter plate is a filling plug which must be opened to fill
the fluid.

TIME TOTALISER: It is located on the front panel..It uses a clock motor to drive a geared
numerical display. The time tantalizer is wired to operate only if the blower receives
power .Hence its display indicates the true time, in hours for which the sampler has
sampled atmospheric air. It can record 0-99999.99 hrs in its memory.

TIMER: A programmable timer is provided to shut off the instrument after pre set time.
The time of delay in operation and operation of machine can be programmed accurate
up to minutes by pressing switches provided on the front panel of the timer. The digital
timer has a built in battery backup which keeps the timer in operation during a failure
of mains power.

POWER ON/OFF SWITCH: MCB is used to control the AC mains power going to the blower
of the machine.
FILTER HOLDER ASSEMBLY: It is rectangular in size. It is mounted on a plate of wire
screen at the top of the filter adaptor assembly.

FILTER PAPER: These are made of micro glass fibers and are expected to be non-
hygroscopic and 98% collection efficiency for particles of 0.5 micron and above. The
size of filter paper is 8’x10’.Recommended filter: Whatman GF/A grade.

TOP COVER: It completely covers the cyclone and filter paper. It has a gasket for air
tightness. Thus It protects the filter paper from vertical falling of material on filter.

OTHER SPECIFICATIOS:
Flow rate:0.9-1.4 m3/min free flow
Power requirements: Normal 220V single phase,50 Hz ,AC Mains
Overall Size &Weight: Approximately 430 x 320 x930mm,45kg

OPORATING INSTRUCTIONS:

SAMPLER START UP SEQUENCE:

• Install the sampler on the ground at a convenient height where the sample is to be
taken.
• Loosen the four wing nuts and remove the top cover. Place a pre-numbered, pre-
weighed conditioned& filter sheet on the backing screen taking care to ensure that
it is centralized.
 • Align the mounting slots to the eye bolts and gently [place it on the filter adapter
assembly. Uniformly tighten the wing nuts maintaining equal pressure on all sides
of the cover.
• Fill the manometer with distilled water up to Zero mark with a syringe.
• Connect the power to the sampler using the main chord provided with.
• Feed the duration of sampling in the timer after setting Real time and Day.
• Record initial Time Totalizer reading.
• Shift left timer button on auto position and shift right button on run position.
• Start the blower using MCB(ON-OFF switch)
• Let water level stabilize and then Record initial manometer reading in m3/min
(about after 5 minutes of operation.)
SAMPLER SHUT OFF SEQUENCE:
After desired run time the sampler will automatically shut off.
• Take the manometer final reading again restarting the blower using on/off switch,
allowing the flow to stabilize for five minutes.
• Record the sampling time indicated by the Time Totalizer.
• Open the top cover and carefully remove the filter paper. Fold the filter paper
along its length so that the solid sides are in contact and are facing inwards. Store
the filter paper in a clean evolve.
• Remove the sampler from the sampling site.
• Take the filter paper to the laboratory and Take the weight of the filter paper with
a precision balance.

Observation & CALCULATION:

Sampling Time = T=30 minutes
Initial wt. of Filter = W1= 2.7141 g
Final wt. of Filter = W2= 2.7197 g
Initial flow rate=1.1 m3 =R1
Final flow rate=1.06 m3 =R2
Avg, flow rate= R=R1+R2/2=
(1.1+ 1.06)/2 = 1.08 m3
Total Air volume= 1.08 X 30 = 32.4 m3

Mass of PM 2.5 collected = W2-W1= 2.7197 g - 2.714 g=0.0056 g =5600 µg

Then The time average Concentration of PM 10= Mass of PM 10/ Total Air Volume
=5600 µg /32.4 m3 = 172.84µg / m3

B)TSPM can be assessed by collection of dust retained in the cyclone cup & adding A &B
Aim of the Experiment: Measurement of Respirable Dust concentration
by PM 2.5 Sampler
(Model: Envirotech APM 550)

Application:-For obtaining samples of Respirable fraction of air borne dust ( i. e. PM 2.5 )

in community areas in Mines and other locations.

Theory(same as APM 460NL) The Respirable dust standard adopted by the Central Pollution
Control Board recommends a 10 micron cut off size for respirable dust measurements.
To protect the communities exposed to particulate matter number of agencies in the
developed world adopted new standards for monitoring PM 2.5 levels in addition to PM
10 standards almost a decay ago. Govt.of Indian notified revised National Ambient Air
quality Standards in November 2010 which includes PM 2.5 as a parameter to be
monitored in community air all over the country.

Principle: The APM 550 sampler uses an Imctor stage which separates particles based
on inertia. The inlet section immediately leads to an impactor stage(PM 10 Impactor)
designed to trap particles with an aerodynamic diameter larger than 10 microns. Thus
the Air stream in the down tube is accelerated through the nozzle of the well shaped
(WINS) impactor designed to trap medium size particles between 2,5 and 10 microns.
The air stream leaving the wins consists of only fine particulates with an aerodynamic
diameter smaller than 2.5 microns. These fine particles are collected on a special Teflon
membrane filter of 47mm dia.

Construction : (Ref.Fig)
APM 550 Dust Sampler is recommended for use in the Indian Mines, manufactured by
Envirotech, New Delhi. It is a fixed point instrument comprising of:

AIR INLET PIPE: Ambient Air laden with suspended particulates enter the system through
the inlet pipe. The air inlet pipe has a circular symmetry so that air entry is un affected
by wind direction and is designed to keep out rain, insects and very large
particles(>100 µm).

Impactor stage (PM10) and PM2.5:- The inlet section immediately leads to an impactor
stage designed to trap particles with an aerodynamic diameter larger than 10 microns
and subsequently by (WINS) impactor designed to trap medium size particles between
2,5 and 10 microns..The (WINS) impactor uses 37 mm diameter GF?A filter paper
immersed in Silicon oil as an impaction surface to avoid particle bounce.

Filter:- The air stream leaving the WINS consists of only fine particulates with an
aerodynamic diameter smaller than 2.5 microns. These fine particles are collected on a
special Teflon membrane filter of 47 mm diameter.

Down Tube:-The down tube is for connection purpose.

Air flow Meter: The Impactor system is designed to operate at an air flow rate of 1m3/hr
or 16.7LPM within +/-5%.Actually, a critical orifice is introduced to control the flow.
Dry gas Meter(DGM): Dry gas Meter has been provided to measure and totalize the
volume of air sampled by the system at actual ambient temperature and pressure. In
DGM the main digits are in meter cube. The digits in red colour are fraction of meter
cube up to three places of decimal value. So the least count of the DGM is 0.001 meter
cube or one litre.

TIME TOTALIZER: The digits in Time Totalizer are in hours. The time tantalizer is wired to
operate only if the pump receives power .Hence its display indicates the true time, in
hours for which the sampler has sampled atmospheric air. It can record 0-99999.99 hrs
in its memory. It is provided on the right side of the front of the pump unit.

Pump: The APM 550 system uses an oil-less rotary pump to produce the suction
pressure and a critical flow control device for maintaining a constant flow rate. The
pump is driven by brushless induction motor capable of withstanding large voltage
fluctuations.

POWER ON/OFF SWITCH: It is a toggle switch & is used to switch on/ switch off the pump.
It is provided on the front of the pump unit.
OPORATING INSTRUCTIONS:

SAMPLER START UP SEQUENCE:

• Weigh a conditioned membrane filter(47 mm dia.)on a micro balance with a
resolution of at least 0.01 milligram. Record the initial filter weight and ID.
Immediately place it in the covered filter carrier provided. To equilibrate the filter
it should be conditioned for 16 hours in desiccator at 25 degree C and RH less
than 35%.
• Open the WINS Impactor assembly and remove the old imaction filter and oil
from the “Well”of the impactor.Place a fresh 37 mm diameter filter in the well
and pour in 1 ml(35 drops)of silicon oil using the dropper provided with the
instrument. Replace the cover of the well and place the unit in the WINS Impactor
base unit. Screw on the cover unit of the WINS Impactor.
• Open the filter holder unit.
• Load the membrane filter on the filter holder unit and mount it on its place.
• Mount the WINS impactor on the filter holder cover.A slight pressure with a bit
of rotary motion will usually cause the system to slide down on the filter holder
cover until it rests on the base.
• Loosen the Gland nut on the top of the instrument to allow the down tube to be
inserted.
• Slip ON the down tube over the WINS imactor followed by the air inlet and PM
10 impactor assembly over the top of the down tube. Tighten the gland nut to
firmly hold and seal the tube protecting the instrument from rain water and dust.
• Connect the mains chord of the pump unit to the power supply.
• Record the Dry Gas Meter and Time totalizer initial readings.
• Switch ON the machine using the toggle switch on the pump assembly.
• At the end of the desired sampling period, record the new DGM reading before
 switching off the pump unit. The difference of final DGM reading and initial
reading will give the Volume of Air sampled in cubic meters.
• Carefully remove the filter from the filter holder and immediately place it in the
covered filter carrier provided. Before taking the weight of the filter equilibrate it
for 16 hours in conditions identical to those at which the filter was conditioned
prior to sampling.
• Take the weight of filter with a precision balance.
CALCULATION:

Sample Start Date: Sample Start Time:

Sample Stop Date: Sample Stop Time:
Initial Reading of DGM in m3 Final Reading of DGM in m3
Total Air Volume= (DGM final reading - DGM initial reading)
Mass of PM 2.5 collected =( Filter final-Filter Initial weight)

The time average concentration of particulates in µg / m3 is given by

Concentration of PM 2.5= Mass of PM 2.5/ Total Air Volume (in µg / m3)

Observation:
Sampling time =30 minutes
Initial wt. of Filter = W1= 1.5956g
Final wt. of Filter = W2= 1.5959 g
Initial Air volume= 1407.072 m3
Final Air volume=1407.572 m3
Total Air volume= 1407.572 m3- 1407.072 m3= 0.5 m3

Mass of PM 2.5 collected = W2-W1= 1.5959 g -1.5956 g = 0.0003g = 300 µg

Then The time average Concentration of PM 2.5= Mass of PM 2.5/ Total Air
Volume =300 µg/0.5 m3= 600 µg / m3

*Note that the time totalizer reading plays no role in the calculation of PM 2.5
concentration and may be used to :
1. Cross check the hours of operation/sampling duration and
2. Maintain a preventive maintenance record of the system.
AIM OF THE EXPERIMENT:- Study of the Construction and Working of
Flame Safety Lamp.
Model: (i) (VELOX GL-50 (ii) VELOX GL-60 (iii)VELOX GL-7 of J.K Dey & Sons
(iv) MSA Type

APPLICATION: The safety lamps are unique type of its kind required for gas testing
operation i.e. Accumulation Test and Percentage Test of Methane in underground coal
mines. The Model VELOX GL-50 is approved by D.G.M.S. for use in Degree I and
Degree II Gassy coal mines where as Model VELOX GL-60 and VELOX GL-7 are
approved by D.G.M.S. for use in Gassy coal mines of all degrees.

PRINCIPLE:
(i) The wire gauge and its principle of action: The iron or copper wire gauzes
are good conductor of heat and allow the gas to pass through them but conduct
the heat of the flame away so quickly that the gas which is not burning on one
side of the gauze fails to reach ignition temperature even though some gas is
burning on the other side of the gauze. The gauze thus allows the gas to pass
through it but not the flame.

(ii) When a methane air mixture comes in contact with the flame of the safety lamp
,the gas in the vicinity of the flame burns forming a gas cap(a pale blue cap)
over the fuel cap,commensurate/proportionate with the concentration of
Methane gas present in the mine air.

(I)VELOX GL- 50 SAFETY LAMP: (Ref. fig.)

CONSTRUCTION:

The GL-50 safety lamp consists of three separable sections which can be screwed
together for complete assembly and use.

(A)Lower section:

(i) Fuel Vessel: It contains the fuel and has ratchet teeth at the top for magnetic locking.
(ii) Oil Filler: It is at the side of the oil vessel with the cap for oil filling.
(iii)Wick Holder (Burner): The round wick passes through it.
(iv)Regulating tube: It is the outer sleeve of the burner. The lower part of it is connected
with the regulating spindle to regulate the flame height.
(v)Regulating Knob: It is at the bottom of the vessel. It is rotated clockwise or anti-
clockwise as per requirement, for the wick adjustment.
(vi)Regulating Spindle: It is connected with the bottom part of the outer sleeve and the
regulating knob, hence the wick height adjustment is done.
(B)Middle section with partly Upper section:

It consists of a composite lower flange screwed on the fuel vessel and a composite middle
ring assemble with five steel (M.S.) pillars to provide bonnet and chimney at the top
and to protect the glass from external hit. The pillars are at such distance that a straight
edge when touching the two pillars will not touch the glass. Separate air inlet and outlet
ports are provided to avoid mixing of fresh inlet air with gases of combustion and for
improvement of air circulation.

(i) Glass retaining ring (Glass seat): A threaded circular brass ring on which the glass
cylinder is placed and is screwed with the lower flange.

(ii) Glass cylinder: A thick toughened cylindrical glass to with stand the shock pressure
inside the lamp and to allow to see the flame through it. During assembly the glass is
provided with asbestos washers at its both end for air tightness.

(iii)Asbestos rings: Two asbestos rings, one each at the bottom and top of the glass are
put to make the joints leak proof and prevent the flame to come outside.

(iv)Magnetic lock: It is a small vertical spring loaded steel bolt housed in a tubular body,
fitted and soldered with the bottom flange.

(C) Upper section:

It consists of a bonnet and chimney with hood provision for enabling mine air near roof
to enter the lamp from the top.
(i)Wire gauzes: (Two numbers) One is the inner gauge and other is the outer gauge made
of iron or copper wire. The copper wire gauzes are of 28 mesh each. These are
protected by the bonnet and are provided not to allow the flame to go out of the lamp.

(i)Bonnet: For protection of wire gauzes. It is double skinned shield and is provided with
a handle to hold the lamp.

MAGNETIC LOCK FUNCTION: The lock bolt passes through the collar into notches
on the oil vessel and when the middle and top section are fitted on the oil vessel by
screwing, the lock bolt prevents their unscrewing by the ratchet construction at the top
end of the oil vessel.

Fuel used:-Petroleum Motor spirit (Petrol), Esso solvent spirit 1425 or SBP 55/115 or
equivalent.
OPERATING PROCEDURE:

(i)The fuel vessel is removed from the top part of the lamp by the Velox Magnetic Un-
locker. The top of the locking device is placed below the top pole of the magnetic-
unlocker in the lamp cabin.
(ii)Motor spirit or solvent spirit is poured by the oil filling can fitted with capillary tube.
The D.G.M.S approved fuels are ESSO Solvent No. 1425 and petrol.
(iii)The flame adjusting tube(outer sleeve) is lowered to allow the wick to come out.
(iv)The wick is trimmed to remove the burnt portion of the wick or it may be removed by
refilling with a new one if the wick is damaged.
(v)Burn the wick at-least for two minutes with a match or a lighter in the lamp cabin to
achieve smooth ignition as the cold wick takes unnecessary long time to light when the
lamp is intended for use..
(vi)The fuel vessel is then screwed to the top part of the lamp and then adjusted for both
testing and lighting flame suitably.

(II)VELOX GL- 60 SAFETY LAMP:

Though the external arrangements of GL-50 and GL-60 are same, the GL-60 is more
sophisticated and has the following differences as compared to GL-50.

(i)The GL-60 has additional bottom feed arrangement to make re-lighting easy and as
well as to detect CO2 nearest to floor of a working place.
(ii)The Fuel Vessel is full of cotton absorbent, eliminating possibility of fuel spillage.
(iii)It has a self contained re-lighting arrangement.
(iv)Wt. with fuel is 1.7kg where as GL-50 is of 1.5 kg.
(v)Automatic flame extinguisher is incorporated to get the flame automatically
extinguished if the fuel vessel of the lamp is accidentally removed during the use due to
failure of magnetic locking system.

RE-LIGHTING SYSTEM:

In the oil vessel there is housing for a dry battery consisting of two cells is 1.5 volt in
series. A filament unit, a filament channel, a spring plate, a snuffer tube and a contact
ring are fitted on the glass seat. A regulating spindle and knob regulate the wick and the
height of the flame. When the regulating knob at the bottom is rotated clockwise, the
outer-sleeve concentric with the tube is lowered. The snuffer tube running through the
glass seat is also lowered since it is supported by the outer sleeve at its lower end and
allows the filament unit to come forward to contact the positive contact bottom. The
filament thus energized, glows and ignites the vapour of the fuel above the wick. As
soon as the flame is produced the regulating knob is turned clockwise so that the
filament ceases to glow.
(III)VELOX GL-7 SAFETY LAMP:

It is similar to GL-60 constructionally but somehow the relighting arrangement differs.

(i)Instead of rotating the knob as in the case of GL-60 , the knob at the bottom of the fuel
vessel is rotated 2-3 tomes by finger and at the same time pulling down the knob thus
completing the circuit of the filament for relighting.
(ii) A methane gas measuring scale is attached to the glass seat.8 nos. of stainless pins are
fixed horizontally according to the length of gas cap from the top of the burner wick.
(iii)It has only top feed arrangement.
(iv)Weight of GL-7 is slightly higher than GL-60

(IV)MSA TYPE Flame Safety Lamp

Description: MSA Flame Safety Lamp is a non re-lighting and top feed type Safety
Lamp. It consists of three separable sections as GL-50 which can be screwed together
for complete assembly and use.

(A)Lower section (Cup and front assembly): (Ref.Fig)

(1)A Fuel vessel which contains the fuel filled with cotton to make the unit spill proof.
(2)A filling plug which is on the top of the oil vessel through which oil is filled.
(3)A wick holder assembly consists of :
i. A body stopper filling hole
ii. A flat wick of dimension ¼” x 6”.
iii. A clip to keep the wick tight and for the accurate setting of the testing flame that
ultimately gives the fine adjustment of the gas cap.
(4) A regulating knob to adjust the wick height.

(B)Middle section with partly upper section: It consist of a composite lower flange and
having a sub-flange, where the lower flange is screwed to the oil vessel and the glass
seat is screwed to the sub-flange and a composite middle annular ring with five steel
rod to provide the bonnet and chimney. The lower section consists of

Cylindrical glass:- A thick toughened glass placed on the glass seat allows the user to
see the flame of the lamp.

Glass retainer (glass seat):- A threaded brass ring on which the glass cylinder is placed
packed with asbestos gaskets.
Magnetic lock: -Two number of anchor beams screwed together functions as the
magnetic lock.

(C)Top Section:
Wire gauges: Two numbers, inner is outer wire gauge and other one is outer wire gauge
made of iron or copper wire. They are provided not to allow the flame of the lamp to go
out of the lamp.
Bonnet:- There are of several cut sections on the bonnet for air inlet and at the top vent
holes for outgoing gases.
Middle annular ring:-It is provided to separate physically the incoming and outgoing
air streams thereby preventing any inter mixing between fresh air and exhaust gases
which in term might effect the true detection of Methane % in Mine air.
Spacer: It is above the bonnet on which a hook with dome assembly has been arranged to
carry the lamp.

Fuel used: Petroleum Motor spirit (Petrol), Esso solvent spirit 1425 or SBP 55/115 or its
equivalent.

Operation: The operation is more or less same as VELOX GL-50 Safety lamp.
Aim of the Experiment: Study of Pitot Static Tube &
Measurement of Air Velocity using Pitot Static Tube and Manometer

Application: Pitot tube is standard equipment for measurement of Velocity of air in

ducts & air pipes.

Principle: When the legs of the Pitot Static tube are connected to the two limbs of a
Manometer via the PVC tubing the velocity pressure is registered (Velocity Pressure
= The pressure difference between the two limbs of the Manometer). This pressure is
a measure of linear velocity of air.

Construction: The Pitot Static tube consists of two concentric tubes. One is the inner
one and other is the outer one.

Pitot Tube (Total head tube) : It is the inner tube placed concentrically inside a
Static tube. It has an open end facing the air stream, so that it measures the total
head. It comprises a head which faces the air stream and stem bent right angle to it.

Static Tube: Out of the two concentric tubes, the outer one is the static tube. It’s nose
(which faces the air stream) and with a few holes on the side of the tube for reading
the static pressure only. The nose is suitably shaped so as to avoid undue turbulence
and hence offer the least resistance to flow.
The Annular Opening between the two tubes at the nose end is sealed. So that the inner
one records the total pressure whereas the outer one records the static pressure only.
The nose is suitable shaped to avoid undue turbulence and hence offer the least
resistance to flow.

Range: Pitot Tubes are available in following ranges: 0.30m, 0.50m, 1.00m, 1.50m.

Velocity Range: 0 to 28m per seconds with suitable Manometer.

Manometer:
The Vertical U-tube manometer is commonly used for measuring pressures above
250pa.It consists of a glass tube of uniform bore bent in U shape. The upper limbs of
the U tube are bent for facilitating connection to flexible rubber tubes. The tube is
normally 6mm internal diameter. Tubes with smaller bores are liable to give erroneous
reading owing to capillarity. The limbs are about 500mm long (the length of course
depending on the range of pressure to be measured) and are about 20mm apart. A
scale graduated in 1mm divisions is placed in between the two limbs. Vertical U tubes
are usually filled with distilled water so that a sensitivity of 9.8pa can be
obtained.Alternativity a least scale graduation of 10/g(10/9.81=1.02mm)may be used
when the manometer will have a sensitivity of 10 pa The U tube is usually mounted on
a wooden board which is mounted vertically on a stand.
Inclined-gauge manometer :
Owing to the limited sensitivity of a Vertical U-tube water gauge, an inclined water
gauge is preferred for accurate work. Here, the whole manometer along with the
board on which it is mounted can be inclined at any angle commensurate with the
degree of sensitivity desired. Usually ,the inclined board is hinged to a horizontal board
which can be leveled properly with the help of two spirit levels mounted on it with
axes at a right angles to each other. The inclination is usually fixed at 0.1 radian so
that a magnification of ten times the reading on vertical water gauge can be obtained.

Procedure for the measurement of air velocity in a Duct:

• The Pitot Static tube is fitted at a measuring point (measuring holes which are
located along the periphery of the Duct) by means of glands provided with the
Pitot tube, facing the Head of the Tube to the air stream.
• Two components of the Pitot tube are connected to the two limbs of the
Manometer via PVC tubing.
• The Manometer is filled with the Manometer fluid.
• Leveling of the Manometer is done by means of the leveling screws and the spirit
levels.
• The Head of the Pitot Static tube is turned to the air stream until the highest
velocity pressure is recorded. It happens at the lowest angle of Yaw.(permissible
angle of Yaw is 10 degrees)
• The pressure difference between the two limbs is found out.(i.e. the pressure
head)

Observation & Calculation for air velocity:

SL.No. Manometer Reading(Wg) in Velocity Remarks
mm
1 7 mm. 10.71m/s. Vertical
position
2 7.76 mm 11.281m/s Inclined
position

Calculation: Velocity can be calculated by the following formula:

V (m/s) = 4.43 √ h/d
Where h = manometer reading in mm Wg, which is equal to velocity pressure in kg/m 2
d = density of gas in kg/ m3 ,
The Equation can be reduced to
V = 4.05√h for air where air density = 1.2 kg/ m3
If ‘h’ is calibrated in Pascal’s ‘p’ (N/m2) then
V (m/s) = 1.41 √ p/d
or = 1.29 √p for air with density of 1.2 kg/ m3

The procedure is repeated in a number of measuring points and the average velocity is
 found out.
Observation: 1.(For Vertical Position).
H=difference between height of manometer fluid (mm)=87-80=7mm.
Velocity =4.05√7=10.71 m/s.

2.For Inclined Position:

h= l sinⱷ θ
tanθ = 1/10)
θ=5.710
l=118-40=78 mm h=78sin5.710=78 X 0.099=7.722

Velocity=4.05√7.722 = 4.05 X 2.7788 =11.25 m/s

Limitations: Pitot Static tubes of normal size should not be used in ducts having
diameter less than 200mm.because in smaller ducts the circumferential measuring
points become too close to the wall of the duct or may even touch it if sufficient
numbers of measurements are to be taken across the duct with the measuring points
located on equal area basis. In such cases measurements should be taken with small
diameter pitot tubes whose outer diameter should not exceed 2.5mm.