suit ▁which ▁back f ired . ▁Dr ink er ▁not ▁only ▁lost ▁the ▁suit , ▁his ▁pat ents ▁were ▁declared ▁invalid . ▁ ▁Em erson ' s ▁new ▁design ▁replaced ▁blow ers ▁and ▁val ves ▁with ▁a ▁flexible ▁dia ph rag m ▁in ▁a ▁dual ▁layer . ▁This ▁acted ▁as ▁a ▁fails a fe : ▁if ▁one ▁layer ▁was ▁torn , ▁the ▁second ▁would ▁continue ▁operation . ▁He ▁also ▁made ▁improvements ▁to ▁the ▁chamber . ▁The ▁first ▁example ▁of ▁this ▁design , ▁nick named ▁" Old ▁Number ▁One ", ▁is ▁currently ▁on ▁display ▁at ▁the ▁Smith son ian ▁Institution ▁in ▁Washington , ▁DC . ▁Em erson ▁continued ▁to ▁make ▁improvements ▁to ▁the ▁iron ▁lung , ▁adding ▁a ▁quick ▁opening ▁and ▁closing ▁function , ▁an ▁improved ▁pressure ▁gauge , ▁and ▁emer gency ▁hand ▁operation . ▁His ▁final ▁improvement ▁was ▁the ▁addition ▁of ▁a ▁transparent ▁positive ▁pressure ▁d ome , ▁allowing ▁vent ilation ▁when ▁the ▁chamber ▁was ▁opened ▁to ▁care ▁for ▁the ▁patient . ▁ ▁Later ▁invent ions ▁In ▁the ▁mid - 1 9 4 0 s , ▁following ▁a ▁suggestion ▁of ▁Dr . ▁Al vin ▁Bar ach , ▁Em erson ▁perfect ed ▁the ▁Th un berg ▁bar osp ir ator , ▁which ▁caused ▁resp iration ▁without ▁moving ▁the ▁l ungs ▁at ▁all . ▁Em erson ▁was ▁involved ▁with ▁the ▁development ▁of ▁high - alt itude ▁flight ▁val ves ▁and ▁SC U BA ▁g ear ▁for ▁the ▁Navy ▁shortly ▁before ▁World ▁War ▁II . ▁ ▁In ▁ 1 9 4 2 ▁he ▁developed ▁an ▁automatic