Abstract: An improved flow-through conductivity sensor is provided. The sensor includes a current return path that has a current return conductor. At least one toroid of the sensor is removed from the flow path and configured to interact with the current return conductor to provide an indication of conductivity. Additional aspects of the invention include disposing a pair of toroids about the current return conductor; disposing a toroid about the current return conductor and configuring the toroid as a transformer.

Abstract: A sensor for sensing turbidity of a liquid sample includes an illumination source, a scattered illumination detector, and a transparent, hydrophilic layer. The illumination source directs incident illumination into the liquid sample without passing through a gas. The scattered illumination detector is disposed to detect at least some illumination scattered in the sample. The transparent, hydrophilic layer is interposed between the source and the liquid sample, and interposed between the detector and the liquid sample. The transparent, hydrophilic layer inhibits bubble formation within the liquid sample proximate at least the incident illumination. A method for sensing turbidity is also disclosed.

Abstract: A system for generating electricity includes a generator and an interface. The generator is coupled to the interface and provides data to the interface regarding electricity generation. The interface is coupled to a control node for monitoring and controlling the generator. The control node may be coupled to the generator through a medium such as the internet. In some aspects of the invention, a continuous emissions monitoring system is provided for fossil-fuel based generators to enhance operation and reduce emissions of such generators.

Abstract: A system for generating electricity includes a generator and an interface. The generator is coupled to the interface and provides data to the interface regarding electricity generation. The interface is coupled to a control node for monitoring and controlling the generator. The control node may be coupled to the generator through a medium such as the internet. In some aspects of the invention, a continuous emissions monitoring system is provided for fossil-fuel based generators to enhance operation and reduce emissions of such generators.

Abstract: A turbidity measurement system with an improved thermal behavior is provided. A turbidity measurement system includes an analyzer and one or more turbidity sensors. Each turbidity sensor includes a source of illumination and a semiconductor-based illumination sensor. The dark current of the semiconductor-based illumination sensor is measured when no illumination is provided by the source. This measured dark current is then used to provide a dark current-compensated turbidity measurement.

Abstract: An ion sensitive field effect transistor pH sensor is provided with an improved sensor gate configuration. Specifically, a tantalum oxide-sensing gate is disposed on top of an alumina layer. The tantalum oxide-sensing gate provides advantageous sensitivity, while the alumina barrier layer increases sensor longevity in situations where the sensor is exposed to caustic cleaning processes such as Clean In Place processes.

Abstract: A system for generating electricity includes a generator and an interface. The generator is coupled to the interface and provides data to the interface regarding electricity generation. The interface is coupled to a control node for monitoring and controlling the generator. The control node may be coupled to the generator through a medium such as the internet. In some aspects of the invention, a continuous emissions monitoring system is provided for fossil-fuel based generators to enhance operation and reduce emissions of such generators.

Abstract: An improved flow-through conductivity sensor is provided. The sensor includes a current return path that has a current return conductor. At least one toroid of the sensor is removed from the flow path and configured to interact with the current return conductor to provide an indication of conductivity. Additional aspects of the invention include disposing a pair of toroids about the current return conductor; disposing a toroid about the current return conductor and configuring the toroid as a transformer.

Abstract: The invention relates to an internal solution ground for primary use with a pH sensor, and preferably with a multi-sensing instrument monitoring a pH sensor and one or more additional secondary sensors having non-isolated circuits. In one aspect, a pH sensor assembly includes a pH electrode, a reference electrode, and an internal solution ground wire. The internal solution ground wire shares a liquid junction with the reference electrode but is protected by the reference fill solution. In one embodiment, the internal solution ground can be electrically isolated through a capacitor or, alternately, a capacitor and resistor in parallel.

Abstract: A system for generating electricity includes a generator and an interface. The generator is coupled to the interface and provides data to the interface regarding electricity generation. The interface is coupled to a control node for monitoring and controlling the generator. The control node may be coupled to the generator through a medium such as the internet. In some aspects of the invention, a continuous emissions monitoring system is provided for fossil-fuel based generators to enhance operation and reduce emissions of such generators.

Abstract: A circulating flow of liquid gasoline is provided to a chemical analyzer for analyzing sulfur concentration. The chemical analyzer vaporizes and combusts a sample of the gasoline to provide an exhaust gas that includes sulfur dioxide produced by combusting the sulfur concentration. The exhaust gas is pressurized and delivered to a flame photometric detector which detects the sulfur dioxide concentration. The sulfur content is inferred from the sulfur dioxide concentration.

Abstract: A combustion gas analyzer for measuring the concentration of a gas constituent in an exhaust gas stream is provided. The gas analyzer includes a sensor cell assembly coupled to a transmitter having electrical circuitry configured to provide an output of the concentration of the gas constituent as sensed by the sensor cell assembly. The combustion gas analyzer also includes a filter substantially enclosing the sensor cell assembly and a conduit coupled to the filter at a first end of the conduit and coupled to a valve assembly at a second end of the conduit. The conduit is used for supplying a calibration gas to the sensor cell assembly or for supplying a blow-back gas used to purge the filter.

Abstract: A chemical analyzer probe includes a gland extending from a tubular end to a second gland end connectable to a chemical analyzer. The gland has a sealing surface that seals to the opening. A porous tubular filter is joined to the tubular end of the gland and forms a filter cavity holding a filter fluid. A coating on the porous tubular filter is formed of a chemically selective material that allows a first chemical in the process fluid to flow into the filter fluid, while excluding a second chemical in the process fluid. A sensor couples to the filter fluid for sensing and connectable to a chemical analyzer through the second gland end.

Abstract: A free chlorine measurement system and sensor are provided. In accordance with one aspect of the invention, the sensor has a porous working electrode disposed in an electrolyte proximate a porous membrane. The membrane allows free chlorine therethrough where it is reduced and generates a current. The current is related to the free chlorine concentration. The internal electrolyte solution is pH stabilized with a long-term pH stabilizer that has a solubility in water at room temperature between about 1.2 moles/liter and about 0.001 moles/liter. The stabilizer can be an acid or a base depending on whether the pH is to be stabilized at a relatively low value or a relatively high value respectively.

Abstract: A process analytic system provides communication between a process analyzer and process sample handling system. The communication allows the process analyzer to modify at least one parameter of the sample handling system to facilitate quick and efficient setup, calibration, and maintenance of the process analytic system. The process analytic system includes a sample handling system that is coupled to a process analyzer to provide a process sample to the process analyzer, and to communicate with the process analyzer. The process analyzer can command the sample handling system to modify at least one sample handling parameter. The process analyzer can modify sample handling parameters based upon sample analysis, diagnostics of the sample handling system, or both.

Abstract: A dissolved oxygen sensor having a cathode and anode immersed in an electrolyte is designed to provide a low background current in the sensor when a potential is applied to the cathode. The background current is maintained at a desired level by selecting the area and length of a channel or path of diffusion of residual oxygen in the electrolyte to the cathode. The area (A) of the diffusion channel in relation to its length (L) is selected to be at or below a selected ratio, A/L.

Abstract: A dissolved oxygen sensor having a cathode and anode immersed in an electrolyte is designed to provide a low background current in the sensor when a potential is applied to the cathode. The background current is maintained at a desired level by selecting the area and length of a channel or path of diffusion of residual oxygen in the electrolyte to the cathode. The area (A) of the diffusion channel in relation to its length (L) is selected to be at or below a selected ratio, A/L.

Abstract: A pH analyzer is operated to measure conductivity of a solution by applying a substantially DC current having peak values, IREF−PEAK, to a reference electrode of an ion-sensitive sensor having an ion-specific electrode in contact with the solution. The reference electrode is coupled to the ion-specific electrode through the solution. The peak voltage, VION−PEAK, between the ion-specific electrode and the common electrode is measured, and the conductivity of the solution is identified based on C SOL = I REF - PEAK V ION - PEAK .

Abstract: A circuit includes an integrator arranged to integrate input signals over a predetermined sample period based on the cycle period of a power source signal. A delay is coupled to the integrator and is responsive to the end of a sample period to delay start of a successive sample period for a predetermined time delay to cancel low frequency noise induced into the circuit during a prior sample period.

Abstract: A pH analyzer is operated to measure pH of a solution by applying a reference electrode current, IREF, to a reference electrode of a pH sensor and an ion-specific electrode current, IGLASS, to an ion-specific electrode of the pH sensor. The currents to the reference electrode and ion-specific electrode are multiplexed to avoid cross-talk. Multiplexing the currents provides a more accurate measurement of electrode impedance for diagnostic purpose. A current spike is optionally added to the reference electrode current to discharge any charge in the solution due to the reference electrode current.