Patent ID: 7464601

Claim:
A disposable manometer for use with a breathing system comprising: a housing having a first chamber and a second chamber, said first chamber is for communication with a breathing gas for respiration of a patient and said second chamber is cylindrical and graduated with non-linear numerical pressure measurements, said second chamber has a vent, said vent is in communication with ambient air; a moving member, said moving member has a frusto-conical peripheral wall with diameters smaller than the internal diameter of said second chamber and the largest diameter of the moving member facing towards the second chamber, said moving member has pointer means placed adjacent to its largest diameter and arranged to be visible through the housing, said moving member moves longitudinally within said housing; a flexible, rolling diaphragm having a first edge sealingly attached between said first chamber and said second chamber of said housing and a second edge sealingly attached to said moving member within said housing thereby forming a seal between said first chamber and said second chamber of said housing, said flexible, rolling diaphragm folds upon itself such that two layers of said flexible, rolling diaphragm are between said frusto-conical wall of said moving member and an internal wall of said second chamber; a port to said first chamber, said port is in communication with said breathing gas; and a spring in said second chamber, said spring is resisting movement of said moving member caused by positive pressure of said breathing gas in said first chamber; said non-linear numerical pressure measurements are calibrated to said spring and the effective diameter of said rolling diaphragm to provide read out for pressures of said breathing gas in said first chamber corresponding to the positions of said pointer means of said moving member relative to said non-linear numerical pressure graduations.