Electronic monitoring control and display apparatus for breathing gas system

Claim 2

In a closed circuit breathing system constituted by a breathing gas circuit including sensor means for producing electrical signals proportional to partial oxygen pressure, and means for displaying the signals produced by said sensor means, and including a breathing gas regenerator means and a supply of regenerating gases including an oxygen supply and a normally closed oxygen solenoid control valve, means for limiting signals from said sensor means to a selected range of amplitudes, means for producing a reference signal having an amplitude intermediate said selected range, first comparator means for comparing said sensor signals limited to said selected range with said reference signal, said display means including a plurality of light emitting elements operated by said comparator means, each said light emitting element corresponding to a selected sub-range of amplitudes within said selected range, and operated by said comparator means when the amplitude of said sensor sigNals is within a selected sub-range, respectively, second comparator means, means for periodically producing a control signal for said second comparator means whereby the comparing of said sensor signals with said reference signal by said second comparator means is made on a periodic basis, and, means for opening said solenoid control valve on said periodic basis only when sensor signals are below said reference signal.

Claim 3

The invention defined in claim 1 wherein said means for periodically producing a control signal for said comparator means is a timing circuit means and the period of said control signal is once about every 5 seconds.

Claim 4

The invention defined in claim 2 wherein said normally closed oxygen solenoid valve when energized is adapted to remain opened for about one half second and admit about one half liter of oxygen into the breathing mixture in said breathing gas circuit.

Claim 5

The invention defined in claim 3 wherein said means for producing a reference signal having an amplitude intermediate said selected range includes means for producing a fixed reference voltage, voltage divider means for stepping said fixed reference voltage into a plurality of discrete levels constituting a subrange, respectively, and there being an intermediate voltage level to constitute said reference signal; said comparator means including a plurality of comparator circuits, one for each discrete voltage level on each side of said intermediate voltage level, means for applying each discrete voltage level to a corresponding comparator, respectively, each of said corresponding comparators including an amplifier, means for applying the limited signals in said selected range of amplitudes to each said amplifier, AND logic circuit means connected to the outputs of said comparators, and means in connecting said AND logic circuit means to said light emitting elements so that only the one light emitting element corresponding to the subrange in which said voltage proportional to a variable lies is energized through said AND logic circuit means to emit light.

Claim 6

The invention defined in claim 4 wherein said ''''AND'''' logic circuit means is constituted by a series of pairs of transistors of alternate conductivity types and connected to receive signals from said comparator means, the transistor pair connected to a higher level comparator having one of said pair connected to a corresponding transistor in the next lower level comparator.

Claim 7

In a breathing system constituted by a breathing gas circuit including a plurality of independent galvanic oxygen pressure sensor means for producing electrical signals proportional to partial oxygen pressure, said breathing system includes a breathing gas regenerator means and a supply of regenerating gas including an oxygen supply and a normally closed oxygen control valve controlling the supply of oxygen to said breathing system, and means for displaying the signals produced by said sensor means, improvements comprising: means associated with each of said sensors for limiting signals to a selected range of amplitudes, means for producing a reference voltage having an amplitude intermediate said selected range, first comparator means for comparing said sensor signals limited to said selected range with said reference signal, means for averaging the signals of said partial oxygen pressure sensor means to produce a voltage proportional to the average output voltage of said sensor means, said display means being a digital display including a plurality of light emitting elements operated by said comparator means, each said light emitting element corresponding to a selected sub-range of amplitudes within said selected range, and operated by said comparator means when the amplitude of said voltage is within a selected sub-range, respectively, a second comparator means for comparing the said voltage proportional to the average output voltage of said sensOrs with said reference voltage and, means for opening said control valve to supply oxygen to said breathing gas system when said voltage proportional to the average output voltage of said sensors is below said reference voltage.

Claim 8

In a breathing system constituted by a breathing gas circuit including a plurality of independent galvanic oxygen pressure sensor means for producing electrical signals proportional to partial oxygen pressure, said breathing system includes a breathing gas regenerator means and a supply of regenerating gas including an oxygen supply and a normally closed oxygen control valve controlling the supply of oxygen to said breathing system, and means for displaying the signals produced by said sensor means, improvements comprising: means associated with each of said sensors for limiting signals to a selected range of amplitudes, means for producing a reference voltage having an amplitude intermediate said selected range, first comparator means for comparing said sensor signals limited to said selected range with said reference signal, means for averaging the signals of said partial oxygen pressure sensor means to produce a voltage proportional to the average output voltage of said sensor means, said display means being a digital display including a plurality of light emitting elements operated by said comparator means, each said light emitting element corresponding to a selected sub-range of amplitudes within said selected range, and operated by said comparator means when the amplitude of said voltage is within a selected sub-range, respectively, a second comparator means for comparing the said voltage proportional to the average output voltage of said sensOrs with said reference voltage and, means for opening said control valve to supply oxygen to said breathing gas system when said voltage proportional to the average output voltage of said sensors is below said reference voltage.

Claim 9

The invention defined in claim 6 including a zener diode connected to the output of said second comparator.

Claim 10

The invention defined in claim 6 including means for producing a periodic control signal for said second comparator means whereby the comparing of said averaged sensor voltage signals with said reference in said second comparator means is on a periodic basis.