Matheson 8068 User manual

Model 8068
Gas Leak Detector
Instrument User Manual
INT-0368 rev A

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SAFETY
QUALITY ASSURANCE
RESPONSIBILITY OF USE
DISPOSAL
CALIBRATION FACILITY
LEGAL NOTICE
INSTRUMENT DESCRIPTION
PACKING LIST
HOW 8068 WORKS
GETTING STARTED
INSTRUMENT MAIN SCREEN
USING THE 8068
HOW TO CONDUCT A CALIBRATION CHECK
INSTRUMENT MAIN SCREEN EXPLAINED
MAIN MENU
CALIBRATION MANAGEMENT
SYSTEM SETTINGS
PROBE OPTIONS
DETECTING LEAKS
INSTRUMENT SPECIFICATIONS
INSTRUMENT WARRANTY AND SERVICE
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DECLARATION OF CONFORMITY
TABLE OF CONTENTS
STATEMENTS
WARRANTY
SERVICE
CONTACT DETAILS
SENSITIVITY
READING DISPLAY
MEASUREMENT UNITS

4
Statements
Safety
Please read this manual in full before using the 8068 instrument. MATHESON takes no respon-
sibility for damage, injury or death resulting from misuse, misunderstanding or negligence
while using this gas detector. Please contact MATHESON for clarification on any aspect of this
manual that is not understood or for additional information required.
This instrument should only be used by qualified or competent persons with suitable knowl-
edge of the hazards relating to the gases contained within equipment or in the local environ-
ment.
Quality Assurance
8068 instruments are manufactured in compliance with ISO9001, which ensures that the
equipment supplied to the customer has been designed and assembled reproducibly from
traceable components, calibrated to traceable standards.
Responsibility of Use
Many gases are hazardous and can cause explosion, poisoning and corrosion resulting in dam-
age to property and life. It is the responsibility of the person using this instrument to ensure it
is being used in accordance with this manual and that the instrument is functioning correctly
before use.
The 8068 can detect a large range of gases but some gases are more dicult to detect.
It is the responsibility of the user to ensure the 8068 instrument has the sensitivity to detect
the required gas before reaching potentially dangerous levels.
Inadequate performance of the gas detection equipment described in this manual may not
necessarily be self-evident and consequently equipment must be regularly inspected and
maintained. MATHESON recommends that personnel responsible for equipment use institute
a regime of regular checks to ensure it performs within calibration limits and that a record be
maintained which logs calibration check data. The equipment should be used in accordance
with this manual, and in compliance with local safety standards.
Disposal
Disposal of the 8068, its components, and any used batteries shall be in accordance with local
and national safety and environmental requirements. This includes the European WEEE (Waste
Electrical and Electronic Equipment) directive.
Calibration Facility
MATHESON oers a calibration service including the issue of certification confirming calibra-
tion to NIST standards.
An 8068 Calibration Kit oers a means of checking and calibrating the instruments against a
known reference, however MATHESON strongly recommend the instrument is returned to an
approved service center on an annual basis for general maintenance and calibration.
Legal Notice
While every attempt is made to ensure the accuracy of the information contained in this man-
ual, MATHESON accepts no liability for errors or omissions, or any consequences deriving from
the use of information contained herein. It is provided “as is” and without any representation,
term, condition or warranty of any kind, either expressed or implied. To the extent permitted
by law, MATHESON shall not be liable to any person or entity for any loss or damage which
may arise from the use of this manual. We reserve the right at any time and without any no-
tice to remove, amend or vary any of the content which appears herein.

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Instrument Description
The 8068 is predominantly used for detecting gas leaks and can detect almost all gases to
varying degrees.
The 8068 uses thermal conductivity as its means of detecting gas, which oers a robust sen-
sor technology that requires practically no maintenance beyond annual servicing.
The 8068 has an easy-to-use graphical interface with an intuitive keypad allowing simple func-
tionality selection and adjustment.
The 8068 has a colored LCD display, LED indicator and audible sounder that indicates the de-
tected signal.
Common applications where the 8068 is already used include:
• Quality assurance - Testing seal integrity after product manufacture
• Laboratory applications - Detection of leaks from mass spectrometers and chromatograph
equipment
• Industrial - Leaks from gas cylinders, pipe work and process equipment
• Medical - Testing of membrane materials and sealing of glove boxes
• Pneumatic - Valve seal testing
The 8068 is calibrated against a 5 E-4 cc/s Helium leak to allow volumetric readings and also a
5000ppm Helium to allow measurement of concentrations.
Selectable Units:
cc/sec
ppm
mg/m3
g/yr
%Vol
Cubic Centimeters per Second oers a reading that indicates the volume of
gas escaping into atmosphere from a single point. ie. leakage from a hole in a
gas filled vessel or pipe.
Parts Per Million is a concentration reading, the 8068 will display the concen-
tration being detected however it is more dicult to gauge the quantity of
leakage.
Milligrams per meter cubed is also a unit that measures concentration. (See
ppm above)
Grams per Year is an alternative measure of leak rate.
This is a measure of the percentage of the target gas in the environment.
IMPORTANT NOTES:
• The 8068 is NOT intrinsically safe, so it should not be using in a potentially explosive environment.
Intrinsically safe instruments are available. Please contact MATHESON for more information.
• Ambient air pressure, heat and humidity can also aect readings.
• The 8068 range is NOT 'Gas Specific' i.e. It can NOT dierentiate between gases.

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Packing List
Please remove all packing material and then check the content of the carry case against the
list below before use. Should the instrument or any accessory appear damaged or missing
then contact the instrument supplier for advice before use.
Model 8068:
• 8068 Instrument
• Box Spanner
• USB Cable
• USB Mains Adaptor
• Warranty Registration Card
• Quick Start Guide

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How the 8068 Works
Thermal Conductivity
All gases conduct heat but by varying amounts, if an object is heated and then the source of
heat is removed, the object will eventually cool down to match ambient air temperature. This
action occurs because the ambient air surrounding the object carries the excess heat into the
surrounding atmosphere.
This principal is also the same for objects that are cooler than the surrounding ambient air.
Dissipation of heat into an air atmosphere is known and is a predictable rate, however, if the
ambient air is replaced with an alternative gas like Helium the rate at which an object cools
down changes.
If the object mentioned above had its environment replaced with pure Helium it would cool
down to the environment temperature about 6 times faster.
The 8068 contains a heated thermistor bead that transmits heat into the sensing chamber. On
the other side of the sensing chamber there is a block of material that remains at a constant
temperature helping to stabilize the signal. As air passes through the detector chamber a con-
stant amount of heat passes from the bead to the air. Gases that are dierent to air will aect
the rate at which heat transmits, these rates of change are measured and displayed as leak
rates.
The 8068 Thermal Conductivity Sensor
A piezo pump draws a small flow of gas through the probe and into the sensing chamber. The
thermistor bead heats up when electrical power is applied. As air passes through the chamber
a constant level of heat is transmitted to the air, this rate of heat transmission is used to 'Zero'
the instrument.
When gases with dierent thermal qualities pass through the chamber, the amount of heat be-
ing transmitted changes. These changes are measured and used to calculate a display reading
on 8068 for leak rates or gas concentrations.
Some gases have similar thermal properties to that of air; therefore, the 8068 can only
detect larger concentrations of these gases.
The 8068 can NOT dierentiate between gases, selecting a specific gas on the 8068 allows
the instrument to calculate concentrations of that gas only if that gas is being detected.

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Getting Started
Charging Your 8068 Instrument
To charge your 8068 instrument, use a USB A to Type C Charger Cable and connect it to the
back of the 8068 device.
The 8068 instrument will indicate it's charging by showing the following symbol
at the top right of the home screen.
The Keypad
The following section explains the general functionality of each key:
'A'
Press ‘A’ to zero the 8068 readings. This
will remove any background readings and
return the display back to near zero.
'B'
Press ‘B’ to start datalogging. Press a sec-
ond time and the datalogging will finish.
UP
Use to scroll up on the LCD display and
change sensitivity.
SELECT/MENU
Use this to accept an option and enter the
Main Menu.
RIGHT
Use to scroll right on the LCD display.
LEFT
Use to scroll left on the LCD display.
DOWN
Use to scroll down on the LCD display and
change sensitivity.
ON/OFF
Press and hold this key for 5 seconds to
switch the instrument 'ON'. To switch the
instrument o, press and hold this key.
This procedure has been designed to avoid
accidental switch OFF.

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Instrument Main Screen
Once the instrument has run through its 'Start up' routine it will display its normal 'Instrument
Main Screen' used when locating gas leaks. Before using the instrument, the various settings
should be set and adjusted to suit the application.

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Using the 8068
WARNING: Before switching the 8068 on, ensure the ambient air is clean as the instrument
automatically Zero's the sensor at switch on. After the instrument has run through its start-up
routine, adjust the instrument settings to the desired levels. Check the instruments sensitivity
using a calibration kit.
Switch the 8068 on by pressing and holding the ON/OFF key, after the instrument has com-
pleted its Zero routine it will enter the main screen.
Gas leaks tend to occur at pneumatic joints or welded seams, hold the 8068 at a 45° angle to
the object being tested and drag the probe along the seam or joint at a rate of approximately
25mm per second.
When a leak is detected the bar graph will start to fill and the frequency of the audio out-
put will increase; this will decrease as the probe moves away from the leak. Return the probe
to the suspected leaking area and move slowly along the same area until the leak is located.
Once the leak has been located, the probe should be held at the leak until the numeric reading
stabilizes.
The live reading bar oers a graphical indication only and should not be used to measure a
leak; you may find that the graph completely fills however the numeric reading will continue to
increase.
Variation in temperature, humidity and background gas may result in a constant level being
detected on the instrument. To reset to Zero, hold the instrument away from the source of leak
or contamination and then press the ZERO key. The instruments display will return to a near
zero reading. It is especially important to move away from any toxic substances when Zeroing
the 8068 to avoid any false negatives which could lead to harm.
The following things will aect the instruments reading:
• Breath of the instrument user contains both CO2and moisture.
• Barometric air pressure and background temperature.
• Sources of cold and heat.