During my PhD, I needed a consistent vapour flow generator for testing out a our BTEX gas sensor system. After a little searching, I came across the excellent Owlstone OVG-4 system.

The Owlstone OVG-4 vapour generator is an incubation based vapour generator that can produce a flow of vapour with specific vapour concentration. The vapour generator consists of a small oven (permeation oven) into which a PTFE tube (containing the target solvent) is placed and held at a fixed temperature. During calibration, the permeation of the solvent through the PTFE tube is calculated and, by varying the flow rate of the air into and out of the chamber, it is possible to change the vapor concentration with high resolution.

While pretty good, the Owlstone system did have one minor flaw – it was manually controlled using push buttons on the front of the system. This lack of computer control meant that all ppm calculations had to be carried out seperatly (the system only shows flow and temperature) and there was no way of automating the system to ramp the concentration over time. This lack of automation meant that running an experiment exploring the range of a sensor system required constant operator intervention and was highly time consuming. To improve on this, I wrote some OVG-4 control software which allowed the system to be controlled from an external computer.

OVG-live can run 3 units simultaneously

OVG-live can run 3 units simultaneously

Experimental example

The software also allowed for the use of a sort of experiment programming, so that complex experiments can be set up and allowed to run with limited requirements on operator time.

I would share the code that does this for any other users of the OVG-4 system however, I no longer own the code. I showed Owlstone this software a little while ago and they bought the code and the rights off me so that they can start bundling the software when they sell the OVG-4 system!

If you have an OVG-4 system then I suggest you contact Owlstone directly and I’m sure they’d be all too happy to sort you out with a copy.