Controlling apparatus of oxygen concentration

PURPOSE:To control the oxygen supply at a constant oxygen concentration and prevent the occurrence of surging, by changing the number of revolutions of a compressor according to the quantity of consumed oxygen to adjust the quantity of air supplied to adsorbing columns. CONSTITUTION:Air is introduced through a solenoid flowmeter 28, supply pipe 3, compressor 4, solenoid pressure gauge 29 and waterdrop separator 5 into nitrogen adsorbing columns 1 and 2 to remove nitrogen therefrom. The air is then fed through a tank 12, flow control valve 13 and solenoid flowmeter 14 from a feed port 15 having an oxygen sensing element 27 into an oxygen utilizing apparatus 16, dispersed in a culture fluid 18 with a baffle 22 and then discharged through a discharge port 17 having an oxygen sensing element 19 and a solenoid flowmeter 20. The sensed values in the sensing element 17, flowmeter 14, sensing element 19 and flowmeter 20 are sent to a controlling apparatus 24 to calculate the quantity consumed oxygen. The valve 13 is adjusted to minimize the quantity consumed oxygen. The value 13 is adjusted to minimize the quantity of discharged O2 gas. On the other hand, delivery pressure and quantity of supplied air sensed by the pressure gauge 29 and flowmeter 28 of the compressor 4 are sent to the apparatus 24 to calculate the number of revolutions of the compressor 4 and control the number of revolutions thereof beyond the surging range.