Gas analysis system design issue

[alchemist_eng]

Hi all,

maybe this is a silly question but I am a newbie in this particular design field. I'm working on a gas analysis system and I'm facing a mechanical design issue. The overall system is made of the electronic board (PCB) with a gas sensors array plus the signal conditioning electronics, a gas chamber on the sensing area and various pneumatic tubes/fittings. The sensors we have choosen are sold with SMD (surface mount) packages so we need a gas chamber that "sits" on the PCB surface (see https://ibb.co/kJtuzF).

Usually gas chambers are circular based in order to include an O-Ring in order to ensure gas tightness but in this case, for design related issues, we need a rectangular based gas chamber. How we can ensure gas tightness with this kind of mechanical geometry? Are there alternative ways than using O-Rings?
Tonio

 

[Nidum]

http://blog.parker.com/racetrack-grooves:-can-o-rings-be-used-in-non-circular-groove-patterns

http://www.parker.com/Literature/O-Ring Division Literature/ORD 5700.pdf

 

[alchemist_eng]

http://blog.parker.com/racetrack-grooves:-can-o-rings-be-used-in-non-circular-groove-patterns

http://www.parker.com/Literature/O-Ring Division Literature/ORD 5700.pdf

Thank you, this is exactly what I'm looking for.
Tonio