Pre-Girffard CO2 guns

[DT Fletcher]

It was with some surprise to find reference of using a CO2 pistol in an 1862 text. Specifically in the k.k. Genie-Koro staff field manual. This, of course, begged the question: How did they manage to use a CO2 gun before CO2 became commercially available in 1890 Paris?

As it turns out, the then accepted laboratory method of producing pressurized CO2 was to use a regular flywheel pumping machine used to pump up airgun tanks. Apparently the flywheel pumping machine was a more commonly available item than previously realized. The flywheel pump would only require minor modification and a low pressure CO2 source. And, importantly, a method of chilling the CO2 receptacle.

There is one known flywheel pumping machine in the Vienna royal war museum and, after looking at it again, it looks exactly like what a CO2 pumping machine should be. The bucket on top surrounding the flask (not really needed when compressing air) would be filled with ice or chilled water to enable the CO2 to change states. Looks like there is an inlet valve up high just underneath where the tank is. This would be the best area to attach the CO2 inlet.

https://flic.kr/p/pQNL8i

A pneumatic pistol of the era would not require any modification at all. Operation would consist of attaching the pistol's air tank to the pumping machine, immerse it in ice, hook up the CO2 generator to the machine, and pump away.

edit: title, of course, should be "Giffard" but can't change the title in editing

[1066]

That's an interesting little snippet - an easy way to cool the cylinder would be partly fill it, then vent some of the gas. This trick is commonly used when filling CO2 match pistols.

[DT Fletcher]

That's an interesting little snippet - an easy way to cool the cylinder would be partly fill it, then vent some of the gas. This trick is commonly used when filling CO2 match pistols.

Same thing with the old Crosman bulk-fill guns (111,112,113,114,115,116,118) which have the CO2 tank built into the gun. After attaching the source tank, cock and fire the gun (unloaded!) a couple times to chill the gun and it will then fill with liquid CO2.

The receiving CO2 tank must be a lower temperature than the source for liquid CO2 to transfer. Doubtless, CO2 behaved the exact same way back in the 1800's and properly explains why this old air tank pumping machine has the bucket top. Will have to contact the museum to see if we can get some closeup pictures of the inlet. If it's up high, it a CO2 machine. A real piece of airgun history.

[plumbgun]

Very interesting. Thank you.