Breathing apparatus with control means for the inhaled gas mixture

Claim 1

AN INHALING OR SIMILAR APPARATUS COMPRISING A MAIN VARIABLE-VOLUME CHAMBER, A PLURALITY OF SECONDARY VARIABLE-VOLUME CHAMBERS, MECHANICALLY CONNECTED PISTONS IN EACH CHAMBER COMPRISING ONE WALL OF EACH CHAMBER, A BREATHING MASK, CONDUIT MEANS CONNECTING THE BREATHING MASK WITH THE MAIN VARIABLE-VOLUME CHAMBER AND THE MAIN VARIABLE-VOLUME CHAMBER WITH THE SECONDARY VARIABLE-VOLUME CHAMBERS, CHECK VALVE MEANS FOR ALLOWING THE PASSAGE OF GAS FROM THE SECONDARY VARIABLE-VOLUME CHAMBERS INTO THE MAIN VARIABLE-VOLUME CHAMBER, A SOURCE OF FRESH BREATHING MIXTURE, CONDUIT MEANS CONNECTING THE SECONDARY VARIABLE-VOLUME CHAMBERS TO THE SOURCE OF FRESH BREATHING MIXTURE, CONTROLLER MEANS RESPONSIVE TO THE PRESSURE IN ONE OF THE SECONDARY VARIABLE-VOLUME CHAMBERS FOR CONTROLLING THE FLOW OF FRESH BREATHING MIXTURE TO SAID ONE SECONDARY CHAMBER WHEN THE PRESSURE THEREIN IS LOWER THAN THE AMBIENT PRESSUREM AND MEANS FEEDING THE OTHER OF SAID SECONDARY CHAMBERS WITH GAS EXHALED FROM THE MASK AND WITH FRESH BREATHING MIXTURE IN ACCORDANCE WITH A PREDETERMINED AMBIENT PRESSURE, THE RATIO OF SAID EXHALED GAS TO SAID FRESH BREATHING MIXTURE IN TERMS OF VOLUME INCREASING WITH AN INCREASE IN AMBIENT PRESSURE.