Method and apparatus for controlling gaseous environment

Claim 3

The method according to claim 1 wherein said parameter comprises the specific heat of the gas in said incubator, said detecting including passing a current through a conductor exposed to gas of said environment and electrically ascertaining the voltage drop produced therein for use in comparison with said desired concentration.

Claim 4

The method according to claim 1 wherein said method further includes controlling the humidity of said environment, and calibrating said Comparison of desired carbon dioxide concentration according to said controlled humidity.

Claim 5

The method according to claim 1 including circulating gas in said environment for producing movement thereof proximate the location of detection of the proportion of carbon dioxide.

Claim 6

Apparatus for controlling the concentration of carbon dioxide in a system providing a gaseous environment including carbon dioxide wherein a source of carbon dioxide is provided therefor, said apparatus comprising: means disposed in relation to said gaseous environment for providing a circulation therein preventing gaseous layering, sensing means located proximate the circulation stream produced by the last mentioned means and responsive to the circulation stream for producing a parameter which changes in accordance with the actual concentration of carbon dioxide at said sensing means, adjustable control means for selecting a value according to the desired concentration of carbon dioxide in said system, means for comparing said parameter produced by said sensing means with the value selected by said adjustable control means, and valve means operable by said comparing means for controlling a flow of carbon dioxide from said source to said gaseous environment so that said actual concentration reaches the desired concentration.

Claim 7

Apparatus for controlling the concentration of carbon dioxide in a system providing a gaseous environment including carbon dioxide wherein a source of carbon dioxide is provided therefor, said apparatus comprising: means disposed in relation to said gaseous environment for providing a circulation therein preventing gaseous layering, sensing means located proximate the circulation stream produced by the last mentioned means and responsive to the circulation stream for producing a parameter which changes in accordance with the actual concentration of carbon dioxide at said sensing means, adjustable control means for selecting a value according to the desired concentration of carbon dioxide in said system, means for comparing said parameter produced by said sensing means with the value selected by said adjustable control means, and valve means operable by said comparing means for controlling a flow of carbon dioxide from said source to said gaseous environment so that said actual concentration reaches the desired concentration.

Claim 8

The apparatus according to claim 5 wherein said sensing means comprises an electrical conductor and means for passing a current through said electrical conductor, said parameter comprising the resistance thereof.

Claim 9

The apparatus according to claim 6 further including bridge means including said conductor, and where said means for comparing comprises comparison amplifier means to which said valve means is responsive, said comparison amplifier means comparing the output of said bridge means with said selected value.

Claim 10

The apparatus according to claim 6 including a bridge means wherein said bridge means includes a reference conductor for balancing said bridge means and wherein current is also passed through said reference conductor, said reference conductor being located proximate said sensing means and responsive to the ambient temperature of the environment, but being closed to the direct influence of gases in the circulation stream.

Claim 11

The apparatus according to claim 5 wherein said means for providing a circulation comprises a motor-operated fan having an impeller located in said gaseous environment.

Claim 12

The apparatus according to claim 9 including a plenum chamber which includes said fan in operable relation therewith, said plenum chamber further including said sensing means in operable relation therewith.

Claim 13

The apparatus according to claim 10 including means for introducing said carbon dioxide into said gaseous environment in the plenum chamber including means directing carbon dioxide into the circulation stream of the plenum chamber upstream from the sensing means.

Claim 14

The apparatus according to claim 5 further including humidity sensitive means also disposed in relation to said gaseous environment for producing a second parameter which changes in accordance with the humidity of said environment, second adjustable control means for selecting a desired humidity value, means for comparing said second parameter with said value by said second adjustable control means, and valve means operable by said comparing means for adding water to aid environment so that the humidity in said system is controlled to the desired value.

Claim 15

Apparatus according to claim 12 including further coupling means operative in response to the desired humidity value for calibrating the comparison of desired carbon dioxide concentration, in accordance with the controlled humidity.

Claim 16

Apparatus for controlling the concentration of a selected gas in a system providing a gaseous environment, wherein a source of said selected gas is provided therefor, said apparatus comprising: a plenum chamber and means disposed in relaTion to said plenum chamber and gaseous environment for providing a circulation of gas from said gaseous environment through said plenum chamber causing the gas in said plenum chamber to be an adequate sample of the gas in said environment, sensing means located in operative relation with said plenum chamber in the circulation stream produced therethrough and responsive to the circulation stream for providing a parameter which changes in accordance with the concentration of said selected gas at said sensing means, said selected gas having a specific heat which differs substantially from that of air, said sensing means being responsive to the divergence in specific heat of said selected gas from the rest of the gaseous environment, control means for selecting a value according to the desired concentration of selected gas in the system, means for comparing said parameter produced by said sensing means with the value selected by said control means means for introducing said selected gas into said gaseous environment in operative relation to the circulation stream through said plenum chamber, and valve means operable by said comparing means for controlling the flow of said selected gas from said source to said means for introducing the selected gas, so that the actual concentration thereof reaches the desired concentration.

Claim 17

Apparatus for controlling the concentration of a selected gas in a system providing a gaseous environment, wherein a source of said selected gas is provided therefor, said apparatus comprising: a plenum chamber and means disposed in relaTion to said plenum chamber and gaseous environment for providing a circulation of gas from said gaseous environment through said plenum chamber causing the gas in said plenum chamber to be an adequate sample of the gas in said environment, sensing means located in operative relation with said plenum chamber in the circulation stream produced therethrough and responsive to the circulation stream for providing a parameter which changes in accordance with the concentration of said selected gas at said sensing means, said selected gas having a specific heat which differs substantially from that of air, said sensing means being responsive to the divergence in specific heat of said selected gas from the rest of the gaseous environment, control means for selecting a value according to the desired concentration of selected gas in the system, means for comparing said parameter produced by said sensing means with the value selected by said control means means for introducing said selected gas into said gaseous environment in operative relation to the circulation stream through said plenum chamber, and valve means operable by said comparing means for controlling the flow of said selected gas from said source to said means for introducing the selected gas, so that the actual concentration thereof reaches the desired concentration.

Claim 18

The apparatus according to claim 14 wherein said means for introducing said selected gas is disposed in said circulation stream before said sensing means so that said sensing means will immediately detect the injection of selected gas by said means for introducing the same.

Claim 21

The apparatus according to claim 14 further including a bridge circuit including said sensing means and also including a reference conductor, said reference conductor being located proximate said sensing means and responsive to the ambient temperature of the environment but being closed to the direct influence of gases in the environment.

Claim 22

The apparatus according to claim 14 wherein said plenum chamber further includes means for changing the temperature of gases flowing therethrough.

Claim 23

The apparatus according to claim 14 further including means located in operative relation to said plenum chamber responsive to the humidity of the circulation stream, and means for controlling said humidity in response to the last mentioned means including means for injecting moisture in relation to said circulation stream so that the humidity reaches a predetermined value.

Claim 24

The apparatus according to claim 14 wherein said selected gas comprises carbon dioxide.

Claim 25

The apparatus according to claim 14 wherein said sensing means comprises an electrical conductor and means for passing a current through said electrical conductor, said parameter comprising the resistance thereof.

Claim 26

Apparatus for controlling the concentration of carbon dioxide in a controlled environment enclosure, said apparatus comprising: sensing means located in communication with the gaseous environment of said enclosure for producing a parameter in accordance with a concentration of carbon dioxide at said sensing means, control means for selecting the desired concentration of carbon dioxide in the enclosure, and means for comparing said parameter with the selected concentration, a source of carbon dioxide and means for coupling said carbon dioxide to said gaseous environment, and valve means disposed in said coupling means for controlling a flow of carbon dioxide therethrough in accordance with said comparison to bring the actual concentration of carbon dioxide to the desired concentration.

Claim 27

Apparatus for controlling the concentration of carbon dioxide in a controlled environment enclosure, said apparatus comprising: sensing means located in communication with the gaseous environment of said enclosure for producing a parameter in accordance with a concentration of carbon dioxide at said sensing means, control means for selecting the desired concentration of carbon dioxide in the enclosure, and means for comparing said parameter with the selected concentration, a source of carbon dioxide and means for coupling said carbon dioxide to said gaseous environment, and valve means disposed in said coupling means for controlling a flow of carbon dioxide therethrough in accordance with said comparison to bring the actual concentration of carbon dioxide to the desired concentration.

Claim 28

The apparatus according to claim 22 further including fan means disposed in cummunication with the gaseous environment of said enclosure for providing a circulation theRein, preventing gaseous layering.

Claim 29

The apparatus according to claim 23 wherein said fan means includes an impeller located within said enclosure, said sensing means being located adjacent said impeller.

Claim 30

The apparatus according to claim 23 including a plenum chamber in communication with said enclosure and including said fan means in operative relation therewith for producing a flow of gas from said enclosure and back into said enclosure, said plenum chamber having said sensing means operative relation therewith for producing said parameter relative to the flow of gas through said plenum chamber.

Claim 31

The apparatus according to claim 25 wherein said enclosure comprises an incubator and said plenum chamber is located substantially above the lower floor of said incubator, and including duct means communicating from said plenum chamber to the lower part of said incubator for delivering the flow of gas from said plenum chamber back into said incubator, and means for coupling the flow of gas from the upper part of said incubator into said plenum chamber.

Claim 32

The apparatus according to claim 26 wherein said duct means extends in coaxial relation through said means for coupling the flow of gas from the upper part of said incubator, the last mentioned means comprising an opening in the upper part of the incubator.

Claim 33

The apparatus according to claim 25 wherein said means for coupling carbon dioxide to said gaseous environment includes means for coupling carbon dioxide to said plenum chamber upstream in the flow of gas from said sensing means.

Claim 34

The apparatus according to claim 25 wherein said enclosure comprises an environmental room having said plenum chamber suspended from a top wall thereof and adapted to direct said flow of gas in a direction initially substantially parallel to said top wall, said plenum chamber having entrance and exit openings at front and rear parallel vertical walls thereof respectively, said fan means being positioned in said rear vertical wall.

Claim 35

The apparatus according to claim 25 wherein said enclosure comprises an incubator and wherein said plenum chamber is located proximate the top interior of said incubator, said plenum chamber having a lower opening, and said fan means having an impeller disposed over said opening for directing a flow of gas longitudinally through said plenum chamber, said plenum chamber being provided with an exit port at at least one end thereof from which the flow of gas leaves said plenum chamber.

Claim 36

The apparatus according to claim 30 wherein said sensing means is disposed between said impeller and said exit port within said plenum chamber.