Valve, Collins Rahn-Otis End-Tidal Sampler, 1982

An ingenious valve that used inspiratory and expiratory pressures to fill a small sampling balloon (yes, a condom) with end-tidal gas for steady-state DLCO tests.  Valve is pictured upside down.  In use the sampling balloon extended below, not above, the mouthpiece.  From the 1982 Collins Supply Catalog.

2 thoughts on “Valve, Collins Rahn-Otis End-Tidal Sampler, 1982”

  1. I used this valve on a Collins system back in 1984. However, the valve was mounted with the condom pointing up, as in the picture. I don’t know if it functionally mattered if the condom was pointing up or down; the field service rep never commented on this nor changed its position. You needed to adjust the sampling flow so the condom would mostly (but not completely) collapse with each breath, and it was easier to see this with the condom pointing up. And yes, that really is a condom; when I ordered Warren E. Collins part #so-and-so, you received authentic Trojan condoms in the red foil wrapper. It was a real hoot having a box of condoms in my desk drawer in a small Catholic hospital!

    1. I had this valve on a Collins Modular Lung Analyzer when I started doing PFTs in 1973. It was mounted with the condom pointing down. Never tried it the other way but I’m not sure it matters since the condom has so little mass it doesn’t take much pressure to keep it inflated. And yes, it was also in a Catholic hospital. Science!!!!

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