Gas detection

Claim 1

Apparatus for the detection of nitric oxide in a gas mixture, comprising; a reaction chamber, sampling means operable to isolate a predetermined amount of the gas mixture, means for supplying a carrier gas to the sampling means, which is further operable to permit the isolated amount of the gas mixture to be swept by the carrier gas as part of a continuous flow into and out of the reaction chamber, the sampling means including a sampling valve having a sampling passage and a bypass passage, the valve including sealing means which in a first position of the valve isolates the sampling passage while the carrier gas is continuously flowing through the bypass passage and preventing intermixing between the carrier gas and gas in the sampling passage and the valve being shiftable to a second position to direct the carrier gas to pass through the sampling passage and sweep the contents thereof as an isolated amount of gas mixture into and out of the reaction chamber, timing means for shifting the valve between the first and second positions at desired intervals of time, means for supplying to the reaction chamber a further gas chemiluminescently reactable with the nitric oxide, and detection means disposed to respond to luminescence emitted in the chamber.

Claim 5

A method for the detection of nitric oxide in a gas mixture, which comprises: withdrawing from a source thereof a gas mixture suspected of containing nitric oxide, continuously passing an inert carried gas to and through a sampling valve and a reaction chamber, shifting said sampling valve to a first position, passing said gas mixture to said valve and passing said carrier gas through a by-pass passage in said valve during the maintenance of said valve in said first position without any intermixing between said carrier gas and said gas mixture, shifting said valve to a second position to seal and isolate a sample of a predetermined amount of said gas mixture thereto and to divert said by-passed carrier gas stream to said isolated gas sample, sweeping said isolated sample from said valve as a discrete sample in said continuous flow of said carrier gas into and out of said reaction chamber, supplying ozone to said reaction chamber and reacting said ozone with any nitric oxide present in said gas sample, detecting the presence of nitric oxide by the luminescence produced in the reacting step, and shifting said valve between said first and second positions at predetermined time intervals.

Claim 6

A method for the detection of nitric oxide in a gas mixture, which comprises: withdrawing from a source thereof a gas mixture suspected of containing nitric oxide, continuously passing an inert carried gas to and through a sampling valve and a reaction chamber, shifting said sampling valve to a first position, passing said gas mixture to said valve and passing said carrier gas through a by-pass passage in said valve during the maintenance of said valve in said first position without any intermixing between said carrier gas and said gas mixture, shifting said valve to a second position to seal and isolate a sample of a predetermined amount of said gas mixture thereto and to divert said by-passed carrier gas stream to said isolated gas sample, sweeping said isolated sample from said valve as a discrete sample in said continuous flow of said carrier gas into and out of said reaction chamber, supplying ozone to said reaction chamber and reacting said ozone with any nitric oxide present in said gas sample, detecting the presence of nitric oxide by the luminescence produced in the reacting step, and shifting said valve between said first and second positions at predetermined time intervals.