Pneumatically controlled respiration device

Claim 1

In a pneumatically controlled respiration device in which breathing gas, taken from a pressure-gas supply source through an injector and volumetrically metered in a pressure regulating valve, is supplied, in the inspiration phase, to the user and discharged, in the expiration phase, through an exhaling valve, the improvement comprising, in combination, a source of respiration gas; a respiration gas enclosure element; an injector connected between said source and said enclosure element for delivering respiration gas thereto; a pressure regulating valve connected to said enclosure element; an exhaling valve means having an opening to atmosphere; a user line connected to said pressure regulating valve and to said opening of said exhaling valve means; said pressure regulating valve including means for volumetrically metering the respiration gas delivered to said user line; said exhaling valve means normally establishing communication between said user line and said opening for the expiration phase and, responsive to application of a control pressure thereto, blocking communication between said user line and said opening to initiate the inspiration phase; means forming a fixed volume control space divided into an inspiration chamber and an expiration chamber; means operable to adjust the ratio of the volumes of said chambers; a source of control gas under pressure; a frequency valve connected to said source of control gas, first and second pneumatic control elements; said first and second elements directly connecting said inspiration and expiration chambers, respectively, on the upstream sides, to said frequency valve and each including means operable, only when enabled, to supply control gas to the associated chamber from said frequency valve for filling of the associated chamber with control gas; said first and second pneumatic control element includes means for enabling the same only when control gas is supplied thereto solely from said frequency valve; third and fourth pneumatic elements each having inputs connected, respectively, to said source of control gas and directly to the downstream sides of said inspiration and expiration chambers, respectively, and each having an output; each of said third and fourth pneumatic elements including means responsive to filling of the associated chamber with control gas for connecting the source of control gas to its output; the output of each second pneumatic element being without pressure until the associated chamber has been filled with control gas; means connecting the output of each third and fourth pneumatic elements to each of said first and second pneumatic control elements, respectively, whereby said first and second pneumatic control elements are responsive to filling of the associated chamber with control gas and thereby, the output of said third and fourth pneumatic elements such that each first and second pneumatic control element is no longer enabled and blocks flow of control gas from said frequency valve to each associated chamber so that the control gas in the associated chamber is discharged through the associated third and fourth pneumatic element; and means connecting the output of the respective fourth pneumatic element connected to said expiration chamber to said exhaling valve means for applying control pressure to said exhaling valve means for closing said opening to atmosphere to initiate the inspiration phase; the respective first pneumatic control element connected to said inspiration chamber being enabled, due to the lack of pressure at the output of the respective third pneumatic element connected to said inspiration chamber, to initiate filling of said inspiration chamber with control gas from said frequency valve; whereby the lengths of the respective phases of the respiration cycle are determined solely by the filling times, and thus the volumes, of the respective chambers.