Blowing raspberries

[HagarTheHorrible]

I have a PH gas hood.  Apart from the obvious putting it on over your head I suspect the correct method of use is to grab the tube/mouthpiece between your teeth, suck in air, not through the tube but from the sides of your mouth before expelling it out of the tube.  Given that the external end of the tube has a rubber flap attached does this mean that when used, hyperventilating soldiers all sounded like ducks blowing raspberries ?  Frighteningly hilarious if that was the case.

[Andrew Upton]

The idea of the mouthpiece was, when gripped in the teeth, to force the wearer to breath in through his mouth and nose (the valve closing shut when breath was drawn in), thus drawing in air affected by poison gas through the chemically treated flannel and neutralising it in the process. Carbon dioxide could then be breathed out through the tube, with the added benefit that this helped prevent the lenses steaming up inside (a particular problem with the earlier Hypo hood). It is indeed possible to blow raspberries through the valve if exhaling with sufficient force. 

 

Edited 22 November , 2018 by Andrew Upton

[GRANVILLE]

I'm sure the men were very aware of what a spectacle they made when the hoods were worn and no doubt the noises that could be produced via the flutter valve, but as the subject of life or death was so serious I doubt this was considered a laughing matter at the time. I believe that the mouth piece was so designed so that the wearer would actually grip it firmly in his mouth and between his teeth so as to ensure that when he exhaled, his breath was pushed outside the hood and that he was supposed to inhale through his nose.

 

David   

[HagarTheHorrible]

There would have been lots of training though, before the realities set in.  It is precisely the incongruous juxtaposition of the deadly seriousness of the situation and the comical "****" (windy-pumps) sounds being made by the soldiers, probably hyperventilating from the stress and panic to get the hoods on and looking at each other, anxiously waiting, to see if someone has been too slow, 

 

Really, you can't use the word ****, that rhymes with tart ?  That's a bit extreme.

Edited 22 November , 2018 by HagarTheHorrible

[wainfleet]

It's not actually a flutter valve. The exhale valve is a piece of folded rubber, evidently made in the shape of an A and with the lower corners cut off for air to escape, but still joined at the end.