Need a small valve for gas injection? Any ideas?

[eigenmax]

Hello everyone,
For injecting gas into a little setup I've got, I have the following mechanism set out. The gas comes from a chemical reaction, goes through a copper capillary, then to a glass tube which was melted in the centre and pulled at both ends to create a thin passage. Then from that to another capillary into the apparatus. I need an idea for a valve. Normal fittings are far too large for the 1mm capillary, so, does anyone have any ideas for a valve that could be opened and closed? I only wish to admit the tiniest quantity of gas.
Thanks

 

[Nidum]

Neoprene tube pinch valve .

 

[eigenmax]

Neoprene tube pinch valve .

Ok, I'll try that.
Thanks

 

[berkeman]

ideas for a valve that could be opened and closed? I only wish to admit the tiniest quantity of gas.

Neoprene tube pinch valve .

And if you want to be able to accurately meter the amount of gas that you allow to move along, you can use the variation of the pinch valve that is a peristaltic pump with a stepper motor to meter the amount of gas/fluid that you push through each time:

https://en.wikipedia.org/wiki/Peristaltic_pump

http://blue-white.com/wp-content/uploads/2013/08/per_pumphead.jpg

 

[eigenmax]

That's really interesting. Thanks for the help.