Abstract: A ventilator implemented completely with fluidic devices provides independent control of inhalation time, exhalation time and breathing gas flow rate. The basic fluidic system comprises a low frequency oscillator which in the form of a flip flop is controlled in its two stable states by means of independently controlled time delay relays. The output of the flip flop is amplified by a digital amplifier and operates an on-off valve which is used to direct breathing gas from the source to the patient. Independent control of the flow rate of the breathing gas is by means of a needle valve. With this basic fluidic system, there are seven other features of the apparatus. One is a maximum pressure control which on inhalation is responsive to the patient's breathing air pressure. The second feature is a sensitivity control, which during exhalation is responsive to the patient inspiratory effort. The third feature is a positive end exhalation pressure control.

Abstract: This invention describes a system of control for a power source-transmission-load system such as might be used on an off-the-road vehicle, for example. The power source is an internal combustion engine having a known optimum characteristic of desired manifold vacuum versus engine speed. The transmission is a hydrostatic or hydromechanical transmission having infinitely variable speed ratio and having a control means for varying said speed ratio.The control system includes a transducer means for measuring engine speed and converting this quantity into an analog fluid pressure proportional to the speed. This analog fluid pressure proportional to speed is modified in a function generator to produce an analog fluid pressure which is proportional to the desired manifold vacuum as a function of engine speed. Means are provided for measuring the actual manifold vacuum and for comparing the actual manifold vacuum with the desired manifold vacuum on a continuous basis.