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Posted

I have this WWII A-14 oxygen mask that's in really good shape. Looking at the inside it seems as if the two inhalation paths are simply covered with a rubber flap - doesn't seem to be any sort of valve involved there. See the first picture.

 

The second picture is attempting to show what's under the flap.

 

Is that how the exhalation was blocked from the inhalation path? By pressurizing the interior of the mask with your breath and closing off the path with the rubber flap? And is thre no other valve involved?

 

What kind of valve is used for the exhalation path going out of the mask?

 

Thanks

A_14_a.jpg

A-14_b.jpg

Posted

This is from AAF Manual 55-0-1, Reference Manual for Personal Equipment Officers, 9 December 1946. "Face masks for use with demand regulators are somewhat similar to a gas mask in operation, though not in design. A single outlet valve is the only mechanically operating feature. The valve is simply a circular rubber flap which opens upon exhalation and closes on inhalation. Proper operation of the entire system thus depends upon suction created in the mask and regulator as the user inhales".

Posted

Ok so then it seems as if both inhale and exhale valves are simple flaps and opening/closure of the flaps is done by breathing in and out creating pressure differences..  Thanks

Posted

The inhalation valve (the demand valve) is actually in the regulator, not the mask, which is opened by suction when the user inhales. There were two types of regulators, Straight Demand which were used only on portable oxygen units and Diluter-Demand which diluted the oxygen with controlled amounts of atmospheric air for a more economical consumption of the oxygen supply.

 

The flaps I think you are calling the inhalation valves were more like baffles to keep from having a "rush" of oxygen to the user when breathing. The only valve in the mask is the exhalation valve.

 

When the user inhaled, the inhalation valve in the regulator opened to allow oxygen to flow into the mask. This inhalation created a suction in the mask closing the exhalation valve in the mask. When the user exhaled, the reverse happened. The pressure created by exhalation closed the demand valve in the regulator and opened the valve in the mask allowing "used' air to exit the mask.

Posted

Ah I see so all the difficult management is in the regulator and not the mask.  This suggests that the mask might be usable if all the rubber is in good condition an dyou have a good regulator.  I wonder if this mask can be connected to modern regulators.

Posted

That is correct! The regulator was the key to the system.

 

There were a couple of types of male fittings on the end of the mask hose. The first fittings were a prong type which was later replaced with the C-ring connector. The C-ring type connector is still used today, so I believe your mask would connect to a modern-day system. 

Posted

This is the connector at the other end of the mask - I take it this is the "C" connector you are referring to?

 

O2_Connector_a.jpg

phantomfixer
Posted

The A-14 mask will plug into a modern … er late 20th century USAF walk around bottle… and if I recall I remember I plugged the mask into the C-5 crew hose… the hose connector has not changed… over the decades…

 

the CRU-60 is the interface between old school hose connector and 3 pin mask hose

phantomfixer
Posted

Even the Raptor uses “old “ style hose connector with a CRU-60

point is, you could don an A-11 (with updated receivers)and A-14 mask and function in a modern jet… with limitations of course

IMG_2589.jpeg

  • 2 weeks later...
pararaftanr2
Posted

What you are seeing is a baffle, added to late production A-14 masks, to help prevent freezing of the mask from exhaled breath at higher altitudes. Looking at the mask from the front, you will see the set of two black plastic "rivets" used to secure the baffle on the interior. Looking at earlier vintage masks from the front, those "rivets" are not there. This was known as the "8th AF modification" and was done at production, not in the field.

usaaf-a-14-oxygen-mask-8th-aaf-modified_14571_pic13_size4.jpg

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