Method and apparatus for automatically determining chlorine and chlorine dioxide concentrations

Claim 3

(b) feeding the gas phase of said gas-liquid phase equilibrator through a sample valve into a gas-liquid chromatograph; (c) separating the gas phase in said gas-liquid chromatograph into air, chlorine and chlorine dioxide by a column which comprises a support selected from the group consisting of diatomaceous earth, activated alumina and polyfluorocarbon beads and a stationary liquid selected from the group consisting of polyfluorocarbon oil, silicone oil and polychlorobiphenyl; (d) determining the respective thermal conductivities of said separated air, chlorine and chlorine dioxide with a thermal conductivity detector, and generating electrical signals which respectively correspond to said thermal conductivities; (e) passing said electrical signals through a variable gain amplifier for amplifying said electrical signals to substantially similar levels, and thereafter through an A/D converter; (f) feeding the outputs of said A/D converter and said temperature sensing means to a micro-computer which calculates the respective concentrations of chlorine and chlorine dioxide in aqueous solution utilizing a correction factor determined from the output of said temperature sensing means; and (g) regulating the feeding of such aqueous solution into said equilibrator and also said variable gain amplifier by said micro-computer.

Claim 4

(b) feeding the gas phase of said gas-liquid phase equilibrator through a sample valve into a gas-liquid chromatograph; (c) separating the gas phase in said gas-liquid chromatograph into air, chlorine and chlorine dioxide by a column which comprises a support selected from the group consisting of diatomaceous earth, activated alumina and polyfluorocarbon beads and a stationary liquid selected from the group consisting of polyfluorocarbon oil, silicone oil and polychlorobiphenyl; (d) determining the respective thermal conductivities of said separated air, chlorine and chlorine dioxide with a thermal conductivity detector, and generating electrical signals which respectively correspond to said thermal conductivities; (e) passing said electrical signals through a variable gain amplifier for amplifying said electrical signals to substantially similar levels, and thereafter through an A/D converter; (f) feeding the outputs of said A/D converter and said temperature sensing means to a micro-computer which calculates the respective concentrations of chlorine and chlorine dioxide in aqueous solution utilizing a correction factor determined from the output of said temperature sensing means; and (g) regulating the feeding of such aqueous solution into said equilibrator and also said variable gain amplifier by said micro-computer.

Claim 5

The method of claim 1, wherein the aqueous solution in said gas-liquid phase equilibrator is acidified to from 0.01 N to 0.1 N with an acid which is selected from the group consisting of hydrochloric acid, sulphuric acid, phosphoric acid, nitric acid, perchloric acid, formic acid, acetic acid, oxalic acid and a mixture of two or more thereof.

Claim 6

The method of claim 1, wherein said temperature sensing means is a platinum wire resistor.

Claim 7

The method of claim 1, wherein said temperature sensing means is a thermocouple.

Claim 8

The method of claim 1, wherein said temperature sensing means is a semiconductor device.

Claim 9

The method of claim 1, wherein said temperature sensing means is a thermistor.