GB761480A - Improvements in distributors for automatic artificial respiration apparatus - Google Patents

Abstract

761,480. Artificial respiration appliances. SPIROTECHNIQUE. June 9, 1954 [June 12, 1953], No. 16964/54. Class 81(2) A distributer for automatic artificial respiration apparatus having a first chamber communicating with the atmosphere through a controlled orifice and a second chamber communicating with the respiratory tracts of the patient and a source of breathable gas through a valve operated by a diaphragm which constitutes a wall common to both chambers, the diaphragm being subjected to the thrust of a spring acting in the direction of opening of the valve, is characterized by the provision of an adjustable valve between the second chamber and the respiratory tracts of the patient and an expiration valve provided on an expiration pipe, the expiration valve opening for the beginning of an expiration phase when the gas pressure in the respiratory tracts of the patient reaches a predetermined value relative to the gas pressure in the second chamber. The distributer comprises two chambers 1, 2 separated by a diaphragm 3 to which a thrust is applied by a spring 15 in the chamber 1 which is open to the atmosphere through an adjustable needle valve 5. A pressure regulator adjacent the distributer comprises two chambers separated by a second diaphragm 11, one chamber being in communication with the atmosphere and housing a spring 12 controlling the second diaphragm 11. A source of gas under pressure is connected to a pipe 13 so that gas flows at constant pressure into the other chamber 14 of the regulator through an inlet valve under the control of the second diaphragm 11 with which it is associated. A valve 9 controls an opening 8 between the other chamber 14 of the regulator and the chamber 2 of the distributer. A duct 6 is connected with a face mask 20, Fig. 2, and is provided with an adjustable cock 7. The face mask 20 is also provided with an exhalation duct 21 provided with an cutlet valve 22 under the control of the gas pressure in the chamber 2. With valve 9 open gas passes into the regulator chamber 14 and the distributer chamber 2 and is kept at constant pressure by the control of the second diaphragm 11 over the inlet valve. Gas then passes to the lungs through the duct 6. As gas flows from the pressure regulator to the chamber 2 of the distributer the pressure in the chamber 2 rises the first diaphragm 3 moves against the spring 15 and causes a blade 16 connected with it and with the valve 9 to move so that the opening 8 is closed and the outlet valve 22 of the mask 20 remains closed. The pressure in the chamber 2 subsequently falls so that valve 22 of the mask 20 opens and gas is exhaled through it by the patient. Finally the pressure in the chamber 2 falls sufficiently for the first diaphragm 3 to move towards the interior of chamber 2 so that the valve 9 again opens and the cycle of operations is repeated.