End of Life (EoL) technology

Isn't it the expensive way?

Chromatograph carrier gas quality is extremely important as it impacts dramatically the GC performance and can also cause complete shutdown. For instruments requiring a purified gas to generate a zero calibration point, a polluted gas causes a calibration error. Despite being so critical, there is currently no cost effective technology to detect or predict a purifier’s end of life. Most users still rely on an instrumentation specialist’s judgement and instrument performance to decide if a purifier’s end of life has been reached. When it occurs, it is often too late. Isn’t it the expensive way?

 

Our new technologies* address two main problems associated with current purifiers. It offers a true real-time end of life detector (not an estimation) and an optional getter life time extender.

End of Life (EoL) detection technology

Our purifier End of Life technology is based on a Pulse Discharge Optical Feedback Detector (PDOFD)*. The innovation of this technology is related to the dual use of a feedback system comprising a low cost optical measurement device and pulse discharge generator. All of this is controlled by a proprietary algorithm and integrated in a compact and low cost design. As a first step, the gas breakdown voltage is detected by ramping a pulsed and frequency modulated high voltage signal across two electrodes that are in direct contact with the gas. The two electrodes are specially designed with a proprietary long lasting material which is the outcome of many years of research. 

The breakdown voltage, which is identified optically when the discharge starts, is a function of the detector internal gas pressure. Consequently, the breakdown voltage is used as a mean to monitor the detector internal pressure without the use of an expensive standalone pressure sensor. 

As a second step, the discharge is maintained and stabilized by an algorithm which stabilizes the discharge current. From the discharge, an optical measurement is done and the gas purity measurement is obtained. A key region of the optical spectrum is monitored to provide a universal measurement to molecules such as H2, O2, N2, CH4, CO, CO2 and H2O.

As a stable long term measurement is required, the measured pressure is used to compensate the purity measurement. Without this compensation, the measurement would be unstable and not usable as a detection limit below 10 ppb is required. This two-step process is repeated continuously to provide a real-time purifier end of life detector. The end of life occurs when the gas purity measurement exceeds a threshold which can be configured by the user.

As the technology can measure the detector internal pressure, it is also used to provide further diagnostic. When coupled with a detector outlet shut-off valve, it is possible to pressurize the detector to that of the purifier supply pressure and monitor the gas system delivery pressure. With this feature, notifications can be sent to the users and prevent catastrophic events such as gas bottles that are running low. This is very often costly as purifiers are most of the time damaged and all instruments polluted. 

Finally, this technology provides even more benefits. As the breakdown voltage is gas type dependent, the algorithm can also detect which gas is being purified or if a major air pollution is occurring. It is also used to provide an automated purifier start-up procedure that only heats the getter when a proper gas, argon or helium for example, is flowing through the purifier. It is not uncommon for purifiers to be damaged from the start.

Extended lifetime technology

Generally, when a heated getter alloy based purifier reaches or gets close to its end of life, the first impurities to break through will be N2 followed by CH4. The technology allows the reduction of the N2 and CH4 load on the getter alloy by reacting them in a plasma reactor pre-stage doped with H2O. They are transformed into NOX, H2O, CO, and CO2 that are more easily trapped in an intermediate chemical trap. This way the getter alloy sees considerably less impurities and its life time is extended.


As all those features can be integrated at a very low cost and in a compact design. It makes this technology a must have for every purification systems and render obsolete competing ones.

Architecture