Abstract: A chromatography device for separating sample fluids from carrier fluids and analyzing the sample is configured so that it is a modular unit. This modularity enables repairs to be quickly effected on the unit and also greatly simplifies the task of accessing the components of the chromatography cartridge. The modular chromatography cartridge is comprised of separation columns for separating the sample fluid from the carrier fluid. The cartridge additionally includes detectors for detecting distinguishing characteristics of fluids exiting the column. Further, the cartridge preferably includes valve assemblies for directing the flow of the carrier fluid and sample fluid throughout the cartridge and restrictors for adjusting the flow rate of the fluids as they flow through the cartridge. All of the components of the cartridge are configured upon a manifold. The manifold has a means for attaching the cartridge to fluid sources and support structure. The manifold enables the system to exhibit its modularity.

Abstract: A dual-column, dual-detector gas detector and analyzer employs both a photo-ionization detector and a flame-ionization detector. In a survey mode, samples of ambient air are driven through both detectors, and the outputs of both detectors are used to determine the presence of one or more gasses. In analysis mode, fixed-volume samples of ambient air are driven through two elution columns having different properties. The output of each elution column is fed to one of the detectors. The arrival times of gas peaks at the two detectors are employed to develop two lists of candidate gasses. The lists are cross-checked for the presence of each candidate on both lists. Candidates identified from their presence on both lists are identified. A further check attempts to identify candidates which are identifiable from their presence on one of the lists, and not on the other. Components identified in this way are added to the final list.

Abstract: A gas chromatograph for measuring the amounts of selected sample gas components such as oxygen and carbon monoxide. The system comprises a high-temperature (600.degree. C.) zirconia cell detector supplied on one side with a continuous stream of oxygen flowing at a constant rate. A voltage source connected to the zirconia cell transports all of this oxygen to the other side of the cell, resulting in a constant background cell current. Sample components from the chromatographic column are injected sequentially into the oxygen stream. When oxygen is injected the cell current increases due to the increase in total oxygen available for transport through the cell. When carbon monoxide is injected, it is fully combusted with the oxygen, and the current correspondingly decreases due to reduction of the oxygen available for transport. The deviation in cell current with reference to the background current is integrated for each component to produce output signals indicating the amount of the component.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: An all-pneumatic process chromatograph having a pneumatically-actuated sample-injection valve, an orifice connected in the column output line to develop a pressure signal corresponding to fluid density, a pneumatic amplifier for strengthening the pressure signal, and pneumatically-operated control means for developing a periodic sample-valve actuating signal and for selecting a particular peak of interest at a controllable time following injection of the sample. The pneumatic control means includes means automatically operable to adjust the time of peak selection in response to changes in actual peak elution time. The temperature-sensitive elements of the apparatus are contained in a chamber which is heated by a source of steam heat, with the rate of heat transfer being regulated pneumatically to maintain a relatively constant temperature within the chamber.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: An all-pneumatic process chromatograph having a pneumatically-actuated sample-injection valve, an orifice connected in the column output line to develop a pressure signal corresponding to fluid density, a pneumatic amplifier for strengthening the pressure signal, and pneumatically-operated control means for developing a periodic sample-valve actuating signal and for selecting a particular peak of interest at a controllable time following injection of the sample. The pneumatic control means includes means automatically operable to adjust the time of peak selection in response to changes in actual peak elution time. The temperature-sensitive elements of the apparatus are contained in a chamber which is heated by a source of steam heat, with the rate of heat transfer being regulated pneumatically to maintain a relatively constant temperature within the chamber.