Device for measuring the humidity of gases

Claim 1

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least the first or ''''wet'''' chamber being made at least in part of a gas-permeable filter material with a pore size allowing water molecules in the air to pass freely, thus constituting means for equalizing air humidity in said first chamber with that of the outside, and for preventing outer air streams to reach said first chamber, the second chamber being a ''''dry'''' chamber; a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a notiCeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; an absorbent rod in said supply tank extending towards the rear of said probe means; a collecting receptacle at the end of said supply tank opposite to that having said chambers thereat; a pressure-compensating capillary connecting said supply tank with said receptacle; and an aerating tube leading from said receptacle to the outside, at a point where possibly exiting liquid does not cause any disturbance.

Claim 2

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least the first or ''''wet'''' chamber being made at least in part of a gas-permeable filter material with a pore size allowing water molecules in the air to pass freely, thus constituting means for equalizing air humidity in said first chamber with that of the outside, and for preventing outer air streams to reach said first chamber, the second chamber being a ''''dry'''' chamber; a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a notiCeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; an absorbent rod in said supply tank extending towards the rear of said probe means; a collecting receptacle at the end of said supply tank opposite to that having said chambers thereat; a pressure-compensating capillary connecting said supply tank with said receptacle; and an aerating tube leading from said receptacle to the outside, at a point where possibly exiting liquid does not cause any disturbance.

Claim 3

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least the first or ''''wet'''' chamber being made at least in part of a gas-permeable filter material with a pore size allowing water molecules in the air to pass freely, thus constituting means for equalizing air humidity in said first chamber with that of the outside, and for preventing outer air streams to reach said first chamber, the second chamber being a ''''dry'''' chamber; a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a notiCeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; an absorbent rod in said supply tank extending towards the rear of said probe means; a collecting receptacle at the end of said supply tank opposite to that having said chambers thereat; a pressurecompensating capillary connecting said supply tank with said receptacle; and an aerating tube leading from said receptacle to the outside, at a point where possibly exiting liquid does not cause any disturbance.

Claim 4

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least the first or ''''wet'''' chamber being made at least in part of a gas-permeable filter material with a pore size allowing water molecules in the air to pass freely, thus constituting means for equalizing air humidity in said first chamber with that of the outside, and for preventing outer air streams to reach said first chamber, the second chamber being a ''''dry'''' chamber; a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a notiCeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; an absorbent rod in said supply tank extending towards the rear of said probe means; a collecting receptacle at the end of said supply tank opposite to that having said chambers thereat; a pressurecompensating capillary connecting said supply tank with said receptacle; and an aerating tube leading from said receptacle to the outside, at a point where possibly exiting liquid does not cause any disturbance.

Claim 13

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said supply tank and a second one of said chambers has a restriction therebetween which constitutes a heat localization spot.

Claim 14

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said supply tank and a second one of said chambers has a restriction therebetween which constitutes a heat localization spot.

Claim 17

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for Substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; a cap on the front end of said first chamber; an inner support carried thereby; and an absorber wick insertable in the latter; wherein said support reaches near said evaporator body, and one of said wick rests on the open end of said evaporator body.

Claim 18

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for Substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; a cap on the front end of said first chamber; an inner support carried thereby; and an absorber wick insertable in the latter; wherein said support reaches near said evaporator body, and one of said wick rests on the open end of said evaporator body.

Claim 21

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected, to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said resistors have negative temperature coefficients; said differentiating means includes first, second and third amplifier circuits, each having two inputs, one of them being of the inverting type; said resistors being connected in respective negative feed-back circuits between said inverting inputs and the outputs of said first and said second amplifier circuits, with said outputs being fed to said inputs of the third amplifier circuit, the latter being connected to operate in the subtracting mode; said indicator means is connected to the output of said third amplifier circuit; said electrical circuit further including a constant-voltage source and switch-over means for selectively linking one of said inputs of said third amplifier circuit with said output of one of said first and said second circuits and with said constant-voltage source, the latter connection for testing and calibrating purposes.

Claim 22

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected, to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said resistors have negative temperature coefficients; said differentiating means includes first, second and third amplifier circuits, each having two inputs, one of them being of the inverting type; said resistors being connected in respective negative feed-back circuits between said inverting inputs and the outputs of said first and said second amplifier circuits, with said outputs being fed to said inputs of the third amplifier circuit, the latter being connected to operate in the subtracting mode; said indicator means is connected to the output of said third amplifier circuit; said electrical circuit further including a constant-voltage source and switch-over means for selectively linking one of said inputs of said third amplifier circuit with said output of one of said first and said second circuits and with said constant-voltage source, the latter connection for testing and calibrating purposes.

Claim 23

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said probe means includes a tubular member lodging said chambers in lengthwise alignmenT; and a handle for ease of manipulation; said first chamber with said evaporator body being attached to the front end of said probe means; said evaporator body having a beaker-formed enlargement; and wherein said first resistor is held near the inner bottom of said evaporator body.

Claim 24

A device for measuring the humidity of gases, comprising, in combination: probe means including two closed chambers, at least a first one of said chambers being made at least in part of a gas-permeable filter material, a supply tank for an evaporating liquid, a porous evaporator body in said first chamber, two temperature-sensitive electric resistors, respectively disposed in said chambers, and means for substantially uniformly supplying said liquid to said evaporator body which latter surrounds a first one of said resistors; a voltage source and an electrical circuit for passing a noticeable current through at least said first resistor so as to increase its temperature, said circuit including electric differentiating means for comparing the resistance values of said resistors; and indicator means connected to the latter for reading therefrom humidity values of a gas in the neighborhood of said probe in proportion to the established resistance values; wherein said probe means includes a tubular member lodging said chambers in lengthwise alignmenT; and a handle for ease of manipulation; said first chamber with said evaporator body being attached to the front end of said probe means; said evaporator body having a beaker-formed enlargement; and wherein said first resistor is held near the inner bottom of said evaporator body.