Sample gas conditioning system Py-ReX

Overview
The Py-ReX filament pyrolyzer module is an add-on for the D-ReX PoS gas detector that enables extractive detection of gases which are too toxic or electrochemically inactive to be measured directly. The module uses the D-ReX PoS integrated pump to draw sample gas through a heated filament contained in a quartz tube, converting the target gas into a measurable species for the detector's electrochemical smart sensor.

Gas detection using a pyrolyzer
The Py-ReX is installed between the sampling point and the gas detector. The D-ReX PoS pump draws the process or ambient sample through the pyrolyzer where pyrolysis occurs; the converted (measured) gas is then delivered to the D-ReX sensor for analysis. This configuration extends the detectable gas range of the D-ReX PoS for process monitoring and safety applications.

How does pyrolysis work?
A filament inside a quartz glass tube is heated to a gas-specific temperature. On contact with the heated filament the target gas decomposes into a different species that the detector can measure. The concentration of the measured species is used to calculate the original target gas concentration according to calibration parameters.

Which gases can be detected?
The Py-ReX is optimized for fluorine-based inerting gases commonly used in semiconductor manufacturing and related industrial processes. It can also detect certain inert non-fluorinated gases (example: 1,2-dichloroethene). Typical measured species include converted products from gases such as C2H2Cl2, C4F6, C5F8, CH3F, NF3 and SF6.

In a nutshell: Equipment and features

• Pyrolysis method: filament pyrolysis (filament in quartz tube)
• Operation: extractive sampling using D-ReX PoS integrated pump
• Communication: 4-20 mA output
• Status indication: 2-colour status LEDs
• Mounting: DIN rail housing (TS35)
• Maximum sample line/tube length: up to 30 m
• Heating current monitoring available on D-ReX PoS
• Optional: Line Integrity Monitoring via D-ReX PoS

Measured gases (examples)
C2H2Cl2 — 1,2-dichloroethene (DCE); C4F6 — hexafluorobutadiene; C5F8 — octafluorocyclopentene; CH3F — methyl fluoride; NF3 — nitrogen trifluoride; SF6 — sulfur hexafluoride

Technical specifications / Characteristics

• Designed as an add-on module for D-ReX PoS using the detector's integrated pump for extractive sampling
• Filament pyrolyzer: heated filament inside a quartz glass tube with gas-specific temperature control
• Installed between sampling point and gas detector
• Converts target gas into a measurable gas; measured concentration is used to calculate target concentration
• Communication output: 4-20 mA
• Visual indicators: 2 coloured status LEDs
• Housing: DIN rail (TS35)
• Maximum sampling line length: up to 30 m
• Heating current monitoring implemented on D-ReX PoS
• Optional Line Integrity Monitoring available on D-ReX PoS
• Application focus: mainly fluorine-based inerting gases in semiconductor manufacturing; also certain non-fluorinated inert gases