TECHNOLOGY FOCUS EXPERT FOCUS
INSIDE THE COULOMETRIC
OXYGEN SENSOR A COMBINED SOLUTION FOR
YOUR UHP GAS PROCESS
PROVIDING A COMPREHENSIVE, SINGLE-SUPPLIER SOLUTION FOR YOUR UHP PROCESS –
FROM PRECISION GAS ANALYSIS TO ENTIRE SYSTEMS AND EXPERT GLOBAL SUPPORT
Servomex’s non-depleting Hummingbird Coulometric sensor
technology is at the heart of our high-purity oxygen analyzer range.
It enables direct measurements at trace and ultra-trace levels,
without the requirement for periodic replacement or false low
readings associated with fuel cell sensors.
The sensor operates on a simple coulometric process whereby
oxygen in the sample gas is reduced in an electrochemical reaction.
The sample gas is in direct contact with the sensor cathode.
Discover our analyzer range:
servomex.com/gas-analyzers
Oxygen (O 2 ) in the sample gas is reduced electrochemically at the
cathode to hydroxyl ions (OH - ). The electrolyte solution contains
potassium hydroxide (KOH) which assists in the migration of OH -
to the high-purity, non-carbon anode, where they are oxidized to
complete the reaction.
Servomex’s analyzer range is the most
comprehensive available from a single
manufacturer, setting the standard for
the ultra-high-purity (UHP) gas market
for decades with a unique ‘all of
market’ solution.
A voltage of approximately 1.3V DC, applied to the sensor electrodes,
drives the reduction and oxidation reactions. The current flow resulting
from the reaction is proportional to the oxygen content in the sample
gas. The processed signal is then displayed on the front panel in parts-
per-million (ppm) or parts-per-billion (ppb) units of O 2 . This provides a
direct measurement for O 2 , eliminating the errors that inevitably result
from technologies that measure the O 2 content indirectly.
Powered by reliable, ground-breaking
sensor technologies, our range delivers
accurate, stable measurements for every
point in your process, with a full range
of percent to ultra-trace measurements.
Servomex analyzers support quality
control, maintaining gas purity during
the production process and detecting
impurities during processes such as
medical gas supply or semiconductor
production.
We also provide solutions for process
control and ensure safety and
emissions monitoring for potentially
hazardous processes.
Our commitment to ongoing
development ensures that even the
most trusted measurements are
continuously improved, with added
features that increase ease of use and
reduce the cost of ownership.
The Coulometric sensor also responds very quickly to changing O 2
concentrations: the 0-1,000ppm range sensor can be exposed to air
and in less than a minute will measure <10ppm on pure nitrogen –
beneficial for users who have upset-prone applications.
Discover our systems solutions:
In addition to fast response to changes in O 2 concentration, the
performance of the sensor is unaffected by reasonable changes in
flow rate. Because the non-depleting sensor is not consumed when
exposed to O 2 , it has a long lifespan and does not require a purge
gas to protect it when it's not in use.
Coulometric sensing complements Paramagnetic oxygen sensing
by being able to measure ppm level measurements, where
Paramagnetic lacks sensitivity at these levels. There are some
limitations however: the sensor cannot be used with gases
containing alcohols, aldehydes and solvents.
DF-550E
servomex.com/systems
10
6.
DF-560E
5m
mm
m
96.5
In addition to individual analyzers,
Servomex also supplies complete
system solutions designed to order for
your project.
State-of-the-art systems engineering
centers in the US, China, India and
Europe provide a global service,
offering solutions ranging from simple
utilities panels to fully-contained air-
conditioned shelters.
Proven experience ensures the optimum
level of efficiency, safety and cost-
effective operation for your application.
DF-760E
Discover our service solutions:
Delivering ultra-trace measurements
of O 2 as a contaminant in UHP
electronic gases, the DF-550E’s fast
response and highly-sensitive 200ppt
Lower Detection Limit (LDL) provides
dependable process monitoring.
Find out more: see page 18
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Designed to measure ultra-trace O 2
to an industry-leading 45ppt LDL,
the DF-560E delivers a fast-response
measurement in multiple
background gases.
Find out more: see page 18
Providing a unique, simultaneous
dual measurement for trace
moisture and trace O 2 , the DF-760E
is a compact solution for monitoring
UHP bulk gases in integrated circuit
board manufacture.
Find out more: see page 21
servomex.com/service-network
Servomex support doesn’t end with
the supply of your analyzer or system.
Our expert team delivers gas analysis
expertise directly to your plant.
With global coverage provided by
service centers and mobile engineers
worldwide, the Servomex Service
Network ensures your processes run
efficiently, safely and profitably.
Support offered includes service contracts,
spares, calibration kits, commissioning,
health checks, training, and equipment
rental. We also provide expert support
from our extensive network of service
centers, or on-site at your facility.
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