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1.0 INTRODUCTION
This manual describes the function; operation and maintenance of the N2 Analyzer. The intent
of this manual is to describe the function of the N2 Analyzer only. The final assembly manu-
facturer should provide operating instructions for the completed assembly. The N2 analyzer is
engineered for long life, maximum reliability and stable performance.
NOTE:
In order to obtain optimum performance from your analyzer, all operation and mainte-
nance must be performed in accordance with this manual. Please read the manual thoroughly
before using the analyzer and do not attempt any repair or procedure that is not described
herein. We cannot warranty any damage resulting from misuse, unauthorized repair or
improper maintenance of the instrument.
2.0 COMPONENT IDENTIFICATION
LCD DISPLAY:
A 3-digit display provides a direct readout of nitrogen concentration in the range
of 0 - 99.9%. The display is blank when the N2 Analyzer enters its sleep (power off) mode. The
N2 Analyzer will automatically enter the sleep mode after 2 minutes from the last time the unit
was energized. You can manually turn off the analyzer by pressing the on/off switch.
ON BUTTON/AUTO OFF:
Use this button to turn the N2 Analyzer on or off. When the N2 Analyzer
is in the Sleep (power off) mode, the LCD display is blank. When the ON button is pressed once,
the analyzer will display the nitrogen concentration for 2 minutes. Pressing the ON button
during this 2 minute "window" will prolong the ON period to 2 minutes from the most recent
time that the button was pushed.
OVER RANGE INDICATOR:
The appearance of a decimal point after the first digit means that the
N2 Analyzer is reading in excess of 99.9%.
Example: 0.0.0 = 100% 0.0.1 = 101%
0.0.2 = 102% (etc).
CALIBRATION KEY:
This key is used to calibrate the device. Holding the key for more than three
seconds will force the device to enter a calibration mode.
OXYGEN SENSOR:
This is used to measure oxygen concentration in sample gas.
SAMPLE INLET CONNECTION:
This is the port at which the device is connected to determine
nitrogen concentration.
3.0 PRE-USE CHECKOUT/
CALIBRATION
Follow these steps before using the N2 Analyzer
1. Prior to turning on the unit, a protective film covering the threaded sensor face
must be removed. After removing the film, wait approximately 20 minutes for the
sensor to reach equilibrium.
2. Pre-assembly, if required.
•
Thread the barbed adapter onto the oxygen sensor.
•
Connect the clear tubing to the barbed adapter.
3. Using the "ON/OFF" key
, make sure the unit is in the power "ON” mode.
4. Press and hold the Calibration Key
for 3 seconds until the display reads
“CAL”. This will calibrate the N2 Analyzer to room air. Thereafter, we recommend
calibration on a weekly basis
A new calibration is required when:
•
The measured N2 percentage in 79.1% N2 is above 80.1% N2
•
The measured N2 percentage in 79.1% N2 is below 78.1% N2
•
If you are unsure about the displayed N2 percentage. (see Factors influencing
accurate readings.)
5. The N2 Analyzer is ready to use.
4.0 OPERATION PRINCIPALS
The instrument display corresponds directly to the oxygen sensor. The oxygen diffuses
through the membrane and an electrical current is generated that is proportional to the partial
pressure of oxygen in the gas sample. The oxygen percentage is subtracted from 100, with the
remainder being displayed as percent nitrogen. The sensor has a minimal response to gases
other than oxygen.
5.0 FACTORS INFLUENCING
ACCURATE READINGS
5.1 Elevation Changes
•
Changes in elevation result in a reading error of approximately 1% of reading per
250 feet.
•
In general, calibration of the instrument should be performed when elevation at
which the product is being used changes by more than 500 feet.
5.2 Temperature Effects
The N2 analyzer will hold calibration and read correctly within ±3% when in thermal equi-
librium within the operating temperature range. The device must be thermally stable when
calibrated and allowed to thermally stabilize after experiencing temperature changes before
readings are accurate.
•
For best results, perform the calibration procedure at a temperature close to the
temperature where analysis will occur.
•
Allow adequate time for the sensor to equilibrate to a new ambient temperature.
CAUTION:
“CAL Err St” may result from a sensor that has not reached thermal equilibrium.
5.3 Pressure Effects
Readings from the N2 analyzer are proportional to the partial pressure of oxygen. The partial
pressure is equal to the concentration times the absolute pressure. Thus, the readings are
proportional to the concentration if the pressure is held constant. Therefore, the following are
recommended:
•
Calibrate the N2 analyzer at the same pressure as the sample gas.
•
If sample gases flow through tubing, use the same apparatus and flow rates when
calibrating as when measuring.
•
The N2 analyzer oxygen sensor has been tested at pressures up to two
atmospheres absolute. Calibration or operation above this pressure is beyond the
intended use.
5.4 Humidity Effects
Humidity (non-condensing) has no effect on the performance of the N2 analyzer other than
diluting the gas, as long as there is no condensation. Depending on the humidity, the gas
may be diluted by as much as 4%, which proportionally reduces the oxygen concentration.
The device responds to the actual oxygen concentration rather than the dry concentration.
Environments where condensation may occur are to be avoided since moisture may obstruct
passage of gas to the sensing surface, resulting in erroneous readings and slower response
time. For this reason, the following is recommended:
•
Avoid usage in environments greater than 95% relative humidity.