The learning objective of this section
is to ensure all personnel involved in
tank atmosphere control operations are
able to properly perform the following
calibrations
calibration of server max Oh a 262
calibration of Rican model 17 HC
calibration of Rican model GP 204
calibration of draegon gas detector pump
a Kuro
check the mechanic 0 first the meter
needle must be exactly on the zero mark
check that the batteries are fully
operational by selecting switch position
b1 the reading should be greater than 60
on the zero to a hundred scale change
the 9-volt battery if the reading is low
selecting switch position B to the
reading should be greater than 60 on the
zero to a hundred scale change the 1.5
volt batteries of the reading is low
frequency of calibration
check the zero adjustment weekly
if there is a large difference in
ambient temperature between the point of
measurement and the last calibration it
is advised that calibration should be
rechecked
zero setting
switch the control to ten percent range
introduce oxygen-free nitrogen into the
indicator at a very very low pressure
stop the gas flow adjust the screw 40
adjustment so that the meter reads zero
percent oxygen
switch the control to the twenty-five
percent range introduce dry air into the
instrument at a very very low pressure
the hand aspirator and a drying tube are
convenient for this stop the gas flow
adjust the screw the Spanish justement
so that the meter reads twenty-one
percent oxygen on the 02 25-percent
scale
when changing from air or oxygen to
nitrogen or vice versa ensure that the
filter
cell
and sample lines have been thoroughly
purged
one minute to the standard hand
aspirator should be enough with the long
sample lines and electrically driven
pump is recommended
place the indicator in the carrying case
the server max OA 262 is ready to use
caution the drying tube must always be
used unless the sample is known to be
dry the analyzer will be damaged if
water or liquids are allowed to get into
the instrument
there is no specific calibration gas to
be used to calibrate this indicator just
carry out the preparation as already
described in the subject indicator
preparation
the instrument is ready to measure
volume percent hydrocarbon gases above
crude oil the external filter co2 filter
is installed
the external filter co2 filter is
removed
the instrument is ready to measure
volume percent hydrocarbon gases in an
inner today atmosphere
if there is a risk of sucking in water
vapor condensation you can use a
moisture collector and install it
between the section holes and the
indicator
calibration potential meter
this adjustment is used set the meter
reading to the desired level while
sampling and known concentration of
combustible gas
in the GP 20 for the top plate must be
removed by taking out the screws from
each corner
the calibration potential meter is a
slotted shaft control located above the
right upper corner of the meter
meter readings are taken on a scale
graduated zero to a hundred percent lel
the rican model GP 204 is calibrated
before shipment to read directly in
percent of lel of isobutene element type
HW 6-2 4-6 in air based on the known lel
for isobutane of one-point-eight percent
by volume
vapor above crude oil is almost equal to
vapor above isobutane
this one-point-eight percent by volume
will produce a reading of 100-percent
lel and lower concentrations will be
read in proportion
other combustible gases will read
approximately correctly in terms of
explosive ability but for maximum
accuracy calibration curves for various
gases have to be used these curves are
delivered with the indicator these
curves are drawn in terms of percent lel
for both coordinates
check the indicators mechanic zero in
order to do this you must observe that
the meter needle is exactly on the zero
mark before the indicators switched on
in this example the span gases butane
and the gas bottles certificate face
value is a concentration of 54.3 percent
of lel
always remember to order a certificate
when purchasing a span gas for the
indicator
introduce ban gasps and record the
reading measured
compare the reading with the values on
the span gasps certificate
the values must be approximately equal
plus minus three percent is acceptable
greater variation indicates the damage
sensor filament when the values are
within the acceptable limit the
indicators ready to use
clean the indicator by introducing clean
air turn the indicator off
never use this indicator to measure
hydrocarbon gas concentration above LVL
heated samples
when sampling spaces such as hot tanks
that a warmer than the instrument
remember that condensation can occur as
a sample passes through the core sample
line water vapor condensed in this way
can block the flow system and corrode
the flame arrestor
a water trap can be used to control this
and available as an accessory
there is no specific calibration
procedure for the day a good multi gas
detector accurate on tubes any use of
the operators requires a full
understanding and strict observation of
the instructions for use of both the
pump and the indicator tubes
the liability for the proper
to the apparatus and use of tubes is
irrevocably transferred to the owner or
operator to the extent of the operators
and tubes must be operated according to
the instruction books