Sample-background autocancellation in fluid-sample analyzers

Claim 1

A system for monitoring a first constituent in a fluid stream, which stream may also include at least one other constituent whose concentration in the stream changes slowly relative to the changes in concentration of tHe first constituent, comprising: first and second monitoring stations, each having respective sensing means for deriving a respective measurement signal in quantitative response to fluid constituents in the respective station, each measurement signal comprising: a principal component, derived in quantitative response to presence of such first constituent in the respective station, and an additional component, derived in quantitative response to presence of such other constituent in the respective station, this additional component being superimposed upon the respective principal component; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream into and through the first station, and thence along a flow path into and through the second station, the flow means comprising: a dilution chamber which is along the flow path between the fluid-exit ports of the two monitoring stations, said chamber having a large volume with respect to the volume of the first monitoring station; signal-processing means for receiving the two signals, each including its respective superimposed principal and additional signal components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principle components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 2

A system for monitoring a first constituent in a fluid stream, which stream may also include at least one other constituent whose concentration in the stream changes slowly relative to the changes in concentration of tHe first constituent, comprising: first and second monitoring stations, each having respective sensing means for deriving a respective measurement signal in quantitative response to fluid constituents in the respective station, each measurement signal comprising: a principal component, derived in quantitative response to presence of such first constituent in the respective station, and an additional component, derived in quantitative response to presence of such other constituent in the respective station, this additional component being superimposed upon the respective principal component; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream into and through the first station, and thence along a flow path into and through the second station, the flow means comprising: a dilution chamber which is along the flow path between the fluid-exit ports of the two monitoring stations, said chamber having a large volume with respect to the volume of the first monitoring station; signal-processing means for receiving the two signals, each including its respective superimposed principal and additional signal components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principle components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 6

A system for monitoring a first constituent in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of such first constituent in the first station; said first station also deriving an additional component of the first measurement signal in quantitative response to presence of such second constituent, and this additional signal component being superimposed upon the principal component of the first measurement signal and constituting a spurious signal component with respect to the quantitative monitoring of such first constituent; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of such first constituent in the second station, and also deriving an additional component of the second measurement signal in quantitative response to presence of such second constituent, this additional signal component being superimposed upon the principal component of the second measurement signal; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through each station; the monitoring stations being flow-through sample and reference cells in a dual-input Michelson-type interferometric infrared spectrometer; the said first and second measurement signals, each including its respective superimposed principal and additional signal components, being optical signals entering the spectrometer at its two inputs, respectively; signal-processing means, comprising the interferometer itself, for receiving the two optical signals and deriving iN response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the said third signal is an output signal of the interferometer, and comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 7

A system for monitoring a first constituent in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of such first constituent in the first station; said first station also deriving an additional component of the first measurement signal in quantitative response to presence of such second constituent, and this additional signal component being superimposed upon the principal component of the first measurement signal and constituting a spurious signal component with respect to the quantitative monitoring of such first constituent; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of such first constituent in the second station, and also deriving an additional component of the second measurement signal in quantitative response to presence of such second constituent, this additional signal component being superimposed upon the principal component of the second measurement signal; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through each station; the monitoring stations being flow-through sample and reference cells in a dual-input Michelson-type interferometric infrared spectrometer; the said first and second measurement signals, each including its respective superimposed principal and additional signal components, being optical signals entering the spectrometer at its two inputs, respectively; signal-processing means, comprising the interferometer itself, for receiving the two optical signals and deriving iN response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the said third signal is an output signal of the interferometer, and comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 18

A system for analyzing gaseous samples, comprising: a gas-chromatograph column, connected to receive such gaseous samples in a stream, and having an active coating material which differentially delays passage through the column of various constituents of such gaseous samples in the stream, said coating material characteristically containing contamination which continuously bleeds from the coating material into the gaseous stream, producing contamination concentration in the stream which changes slowly relative to the changes in concentration of the differentially-delayed constituents; first and second monitoring stations, each having sensing means for deriving a principal component of a measurement signal in quantitative response to presence of the differentially delayed constituents in the corresponding station, each of the two resulting measurement signal principal components having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, in the corresponding station, each of the two resulting measurement signals also having a spurious component derived in quantitative response to presence of the contamination in the corresponding station, this spurious component being superimposed upon the sequentially different amplitudes of the corresponding principal component; flow means, connected to the chromatograph column and to both the first and second monitoring stations, for directing the fluid stream from the chromatograph column through each station and for further delaying the arrival of the differentially delayed constituents at the second station; signal-processing means for receiving the two signals and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the two said spurious signal components arising from the contamination in the column coating material, whereby the third signal comprises substantially only a component whose sequentially different amplitudes correspond to the sequential presences of the differentially delayed constituents in the stream, respectively; and utilization means responding to the third signal.

Claim 19

A system for analyzing gaseous samples, comprising: a gas-chromatograph column, connected to receive such gaseous samples in a stream, and having an active coating material which differentially delays passage through the column of various constituents of such gaseous samples in the stream, said coating material characteristically containing contamination which continuously bleeds from the coating material into the gaseous stream, producing contamination concentration in the stream which changes slowly relative to the changes in concentration of the differentially-delayed constituents; first and second monitoring stations, each having sensing means for deriving a principal component of a measurement signal in quantitative response to presence of the differentially delayed constituents in the corresponding station, each of the two resulting measurement signal principal components having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, in the corresponding station, each of the two resulting measurement signals also having a spurious component derived in quantitative response to presence of the contamination in the corresponding station, this spurious component being superimposed upon the sequentially different amplitudes of the corresponding principal component; flow means, connected to the chromatograph column and to both the first and second monitoring stations, for directing the fluid stream from the chromatograph column through each station and for further delaying the arrival of the differentially delayed constituents at the second station; signal-processing means for receiving the two signals and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the two said spurious signal components arising from the contamination in the column coating material, whereby the third signal comprises substantially only a component whose sequentially different amplitudes correspond to the sequential presences of the differentially delayed constituents in the stream, respectively; and utilization means responding to the third signal.

Claim 20

A system for analyzing gaseous samples, comprising: means for providing a stream of carrier gas along a flow path and for injecting a slug of such gaseous sample into such stream; a gas-chromatograph column, connected to the said flow path to receive such slug of gaseous sample in the stream of carrier gas, and having an active coating material which differentially delays passage through the column of various constituents of such gaseous sample in the stream, said carrier gas being characterized by contaminantS, present even upstream of the point where the sample slug is injected, whose concentration in the effluent stream from the column changes only very slowly relative to the changes in concentration of the differentially-delayed constituents; a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of the differentially delayed constituents in the first station, said first measurement signal''s principal component having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, said first measurement signal also having a spurious component derived in quantitative response to presence of the carrier-gas contaminants in the first station, this spurious component being superimposed upon the sequentially different amplitudes of the principal component of the first measurement signal; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of the differentially delayed constituents in the second station, said second measurement signal''s principal component having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, said second measurement signal also having a spurious component derived in quantitative response to presence of the carrier-gas contaminants in the second station, this spurious component being superimposed upon the sequentially different amplitudes of the principal component of the second measurement signal; flow means, connected to the chromatograph column and to both the first and second monitoring stations, for directing the fluid stream from the chromatograph column through each station and for further delaying the arrival of the differentially delayed constituents at the second station; signal-processing means for receiving the two signals, each including its respective superimposed principal and spurious components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the two said spurious signal components arising from the carrier-gas contaminants, whereby the third signal comprises substantially only a component whose sequentially different amplitudes correspond to the sequential presences of the differentially delayed constituents in the stream, respectively; and utilization means responding to the third signal.

Claim 21

A system for analyzing gaseous samples, comprising: means for providing a stream of carrier gas along a flow path and for injecting a slug of such gaseous sample into such stream; a gas-chromatograph column, connected to the said flow path to receive such slug of gaseous sample in the stream of carrier gas, and having an active coating material which differentially delays passage through the column of various constituents of such gaseous sample in the stream, said carrier gas being characterized by contaminantS, present even upstream of the point where the sample slug is injected, whose concentration in the effluent stream from the column changes only very slowly relative to the changes in concentration of the differentially-delayed constituents; a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of the differentially delayed constituents in the first station, said first measurement signal''s principal component having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, said first measurement signal also having a spurious component derived in quantitative response to presence of the carrier-gas contaminants in the first station, this spurious component being superimposed upon the sequentially different amplitudes of the principal component of the first measurement signal; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of the differentially delayed constituents in the second station, said second measurement signal''s principal component having sequentially different amplitudes which correspond to the sequential presences of the differentially delayed constituents, respectively, said second measurement signal also having a spurious component derived in quantitative response to presence of the carrier-gas contaminants in the second station, this spurious component being superimposed upon the sequentially different amplitudes of the principal component of the second measurement signal; flow means, connected to the chromatograph column and to both the first and second monitoring stations, for directing the fluid stream from the chromatograph column through each station and for further delaying the arrival of the differentially delayed constituents at the second station; signal-processing means for receiving the two signals, each including its respective superimposed principal and spurious components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the two said spurious signal components arising from the carrier-gas contaminants, whereby the third signal comprises substantially only a component whose sequentially different amplitudes correspond to the sequential presences of the differentially delayed constituents in the stream, respectively; and utilization means responding to the third signal.

Claim 22

A system for monitoring a first constituent in a fluid stream, which stream may also include at least one other constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: first and second monitoring stations, each having respective sensing means for deriving a respective measurement signal in quantitative response to fluid constituents in the respective station, each measurement signal comprising: a principal component, derived in quantitative response to presence of such first constituent in the respective station, and an additional component, derived in quantitative response to presence of such other constituent in the respective station, this additional component being superimposed upon the respective principal component; flow means, connected to both the first and second monitoring stations, for splitting the fluid stream at a branch point and directing part of the stream thence along a first flow path into and through the first station, and along a second, parallel flow path into and through the second station, the flow means comprising: a dilution chamber which is along the second flow path between the branch point and the fluid-exit port of the second station, said chambeR having a large volume with respect to the volume of the first station; signal-processing means for receiving the two signals, each including its respective superimposed principal and additional signal components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 23

A system for monitoring a first constituent in a fluid stream, which stream may also include at least one other constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: first and second monitoring stations, each having respective sensing means for deriving a respective measurement signal in quantitative response to fluid constituents in the respective station, each measurement signal comprising: a principal component, derived in quantitative response to presence of such first constituent in the respective station, and an additional component, derived in quantitative response to presence of such other constituent in the respective station, this additional component being superimposed upon the respective principal component; flow means, connected to both the first and second monitoring stations, for splitting the fluid stream at a branch point and directing part of the stream thence along a first flow path into and through the first station, and along a second, parallel flow path into and through the second station, the flow means comprising: a dilution chamber which is along the second flow path between the branch point and the fluid-exit port of the second station, said chambeR having a large volume with respect to the volume of the first station; signal-processing means for receiving the two signals, each including its respective superimposed principal and additional signal components, and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 25

A system for monitoring a first constituent intermittently present in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: first and second monitoring stations, each having sensing means for deriving a principal component of a measurement signal in quantitative response to presence of such first constituent in the respective station; said first and second station also each deriving an additional component of the respective measurement signal in quantitative response to presence of such second constituent, and this additional signal component being superimposed upon the principal component of the respective measurement signal and constituting a spurious signal component with respect to the quantitative monitoring of such first constituent; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through the two stations in parallel; signal-processing means for receiving the two signals and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 26

A system for monitoring a first constituent intermittently present in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: first and second monitoring stations, each having sensing means for deriving a principal component of a measurement signal in quantitative response to presence of such first constituent in the respective station; said first and second station also each deriving an additional component of the respective measurement signal in quantitative response to presence of such second constituent, and this additional signal component being superimposed upon the principal component of the respective measurement signal and constituting a spurious signal component with respect to the quantitative monitoring of such first constituent; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through the two stations in parallel; signal-processing means for receiving the two signals and deriving in response thereto a third signal which is a mathematical function of the first two signals, the function being such as to effect substantially complete mutual cancellation of the said additional measurement signal components, whereby the third signal comprises substantially only the principal components, corresponding to presence of the first constituent in the stream; and utilization means responding to the third signal.

Claim 27

A system for monitoring a first constituent in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of such first constituent in the first station; said first station also deriving an additional component of the first measurement signal in quantitative response to presence of such second constituent, and this additional component being superimposed upon the principal component and constituting a spurious signal component with respect to such quantitative monitoring of such first constituent; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of such first constituent in the second station, and also deriving an additional component of the second measurement signal in quantitative response to presence of such second constituent, this additional component being superimposed upon the principal component of the second measurement signal; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through each station, the flow means comprising a flow-delay path for establishing a time interval between arrival of corresponding portions of fluid from the fluid stream at the two stations, which interval is approximately equal to, or slightly greater than, the time interval corresponding to the width of a typicAl sample constituent''s measurement-signal peak, halway up the peak as measured above the contaminant background; signal-processing means for receiving the two signals, each including its respective principal and additional components, and deriving in response thereto a third signal whose magnitude is equal to the time integral of the difference between the first two signals; and utilization means responding to the third signal.

Claim 28

A system for monitoring a first constituent in a fluid stream, which stream may also include a second constituent whose concentration in the stream changes slowly relative to the changes in concentration of the first constituent, comprising: a first monitoring station, having first sensing means for deriving a principal component of a first measurement signal in quantitative response to presence of such first constituent in the first station; said first station also deriving an additional component of the first measurement signal in quantitative response to presence of such second constituent, and this additional component being superimposed upon the principal component and constituting a spurious signal component with respect to such quantitative monitoring of such first constituent; a second monitoring station, having second sensing means for deriving a principal component of a second measurement signal in quantitative response to presence of such first constituent in the second station, and also deriving an additional component of the second measurement signal in quantitative response to presence of such second constituent, this additional component being superimposed upon the principal component of the second measurement signal; flow means, connected to both the first and second monitoring stations, for directing fluid from the fluid stream through each station, the flow means comprising a flow-delay path for establishing a time interval between arrival of corresponding portions of fluid from the fluid stream at the two stations, which interval is approximately equal to, or slightly greater than, the time interval corresponding to the width of a typicAl sample constituent''s measurement-signal peak, halway up the peak as measured above the contaminant background; signal-processing means for receiving the two signals, each including its respective principal and additional components, and deriving in response thereto a third signal whose magnitude is equal to the time integral of the difference between the first two signals; and utilization means responding to the third signal.