Abstract: A fluid analyzer having an electrical heater includes an intrinsic safety barrier that provides voltage and current from a power source to an electrical load and includes a voltage limiter and an infallible current limiting resistor for limiting the voltage and current provided to respective intrinsically safe levels, where the voltage limiter is arranged in a flameproof/explosion proof or pressurized/purged enclosure, and the current limiting resistor, e.g., an electrical heater, is connected via a connecting line to the voltage limiter and arranged outside the flameproof/explosion proof or pressurized/purged enclosure in an enclosure configured to provide protection against contact and ingress without being flameproof/explosion proof or pressurized/purged.

Abstract: A Gas Chromatograph (GC) detector comprises a first circuit, a second circuit, a digital subtractor and a digital logic shared between one to many detector channels to provide a GC measurement in a digital form. The first circuit includes a first counter circuitry to provide a first counter output. The second circuit includes a second counter circuitry to provide a second counter output. The GC detector includes a digital subtractor to subtract the first counter output from the second counter output and provide a digital subtractor output. The GC detector further includes a digital logic shared between one to many detector channels to implement at least a portion of the first counter circuitry and the second counter circuitry. The digital logic to receive the digital subtractor output and provides the GC measurement in the digital form.

Abstract: A fluid pressure control apparatus includes a proportional solenoid valve operatively connected between a fluid inlet and a fluid outlet and a pressure sensor fluidically coupled to the fluid outlet, wherein an electronic controller generates and outputs a control signal to the solenoid valve in dependence on a first signal from the pressure sensor and a second signal corresponding to a pressure set point, where the solenoid valve has a rest position between opened and closed, and the electronic controller is further adapted to generate the control signal with either of opposite polarities to move the valve in either of opposite directions from its rest position in order to reduce power consumption and heat generation, in particular for use in gas analysis equipment located in hazardous areas.

Abstract: A fluid analyzer having an electrical heater includes an intrinsic safety barrier that provides voltage and current from a power source to an electrical load and includes a voltage limiter and an infallible current limiting resistor for limiting the voltage and current provided to respective intrinsically safe levels, where the voltage limiter is arranged in a flameproof/explosion proof or pressurized/purged enclosure, and the current limiting resistor, e.g., an electrical heater, is connected via a connecting line to the voltage limiter and arranged outside the flameproof/explosion proof or pressurized/purged enclosure in an enclosure configured to provide protection against contact and ingress without being flameproof/explosion proof or pressurized/purged.

Abstract: A fluid pressure control apparatus includes a proportional solenoid valve operatively connected between a fluid inlet and a fluid outlet and a pressure sensor fluidically coupled to the fluid outlet, wherein an electronic controller generates and outputs a control signal to the solenoid valve in dependence on a first signal from the pressure sensor and a second signal corresponding to a pressure set point, where the solenoid valve has a rest position between opened and closed, and the electronic controller is further adapted to generate the control signal with either of opposite polarities to move the valve in either of opposite directions from its rest position in order to reduce power consumption and heat generation, in particular for use in gas analysis equipment located in hazardous areas.

Abstract: A Gas Chromatograph (GC) detector comprises a first circuit, a second circuit, a digital subtractor and a digital logic shared between one to many detector channels to provide a GC measurement in a digital form. The first circuit includes a first counter circuitry to provide a first counter output. The second circuit includes a second counter circuitry to provide a second counter output. The GC detector includes a digital subtractor to subtract the first counter output from the second counter output and provide a digital subtractor output. The GC detector further includes a digital logic shared between one to many detector channels to implement at least a portion of the first counter circuitry and the second counter circuitry. The digital logic to receive the digital subtractor output and provides the GC measurement in the digital form.

Abstract: A thermal conductivity detector includes a heatable resistive detector configured to be physically arranged in an analytes flow eluting from a chromatography column and electrically arranged with resistors in separate arms of a measuring bridge, an amplifier which detects differential voltage between two opposite nodes of the bridge and applies an output voltage to other opposite nodes of the measuring bridge to maintain the detector at a constant operating temperature, and an additional resistor with a controllable switch in parallel connected in series with the detector or resistor arranged in one arm of the bridge, where the switch is periodically turned on and off at a predetermined duty cycle and/or controlled by information on characteristic times-of-arrival of analytes at the detector to compensate for operating temperature uncertainties due to manufacturing variations of the resistors and/or to allow for processing small and large peaks of a chromatogram with highest available resolution.

Abstract: A thermal conductivity detector for a gas chromatograph includes a heatable resistive detector element configured to be physically arranged in a flow of analytes eluting from a chromatography column and electrically arranged together with resistors in separate arms of a measuring bridge, wherein to provide a new configuration of the thermal conductivity detector to allow high detector sensitivity and to meet intrinsic safety requirements, the detector element includes at least two equal detector sub-elements that are configured to be physically arranged in series in the flow of analytes and electrically arranged in parallel with each other, where the detector element in one arm and a reference resistor in the other arm of the same half of the measuring bridge are configured such that the total resistance of the parallel detector sub-elements at operating temperature is at least approximately equal to the resistance of the reference resistor.

Abstract: A thermal conductivity detector includes a switch controllable to short-circuit the input of an amplifier to improve the thermal conductivity detector for use in gas chromatography without the need of an additional reference cell, wherein a digital signal processor calculates a transfer function of an analog signal processor from a digitized difference signal received in response to short-circuiting the input of the amplifier at a given time when solely a reference carrier fluid passes through a measuring cell, and the digital signal processor recovers a detector signal by deconvoluting the digitized difference signal with a transfer function.

Abstract: A thermal conductivity detector for a gas chromatograph includes a heatable resistive detector element configured to be physically arranged in a flow of analytes eluting from a chromatography column and electrically arranged together with resistors in separate arms of a measuring bridge, wherein to provide a new configuration of the thermal conductivity detector to allow high detector sensitivity and to meet intrinsic safety requirements, the detector element includes at least two equal detector sub-elements that are configured to be physically arranged in series in the flow of analytes and electrically arranged in parallel with each other, where the detector element in one arm and a reference resistor in the other arm of the same half of the measuring bridge are configured such that the total resistance of the parallel detector sub-elements at operating temperature is at least approximately equal to the resistance of the reference resistor.

Abstract: A thermal conductivity detector includes a heatable resistive detector configured to be physically arranged in an analytes flow eluting from a chromatography column and electrically arranged with resistors in separate arms of a measuring bridge, an amplifier which detects differential voltage between two opposite nodes of the bridge and applies an output voltage to other opposite nodes of the measuring bridge to maintain the detector at a constant operating temperature, and an additional resistor with a controllable switch in parallel connected in series with the detector or resistor arranged in one arm of the bridge, where the switch is periodically turned on and off at a predetermined duty cycle and/or controlled by information on characteristic times-of-arrival of analytes at the detector to compensate for operating temperature uncertainties due to manufacturing variations of the resistors and/or to allow for processing small and large peaks of a chromatogram with highest available resolution.

Abstract: A thermal conductivity detector includes a switch controllable to short-circuit the input of an amplifier to improve the thermal conductivity detector for use in gas chromatography without the need of an additional reference cell, wherein a digital signal processor calculates a transfer function of an analog signal processor from a digitized difference signal received in response to short-circuiting the input of the amplifier at a given time when solely a reference carrier fluid passes through a measuring cell, and the digital signal processor recovers a detector signal by deconvoluting the digitized difference signal with a transfer function.

Abstract: An intrinsically safe energy limiting circuit for connection between an upstream DC power source and a downstream electrical load powered from the upstream DC power source, wherein the circuit comprises from upstream to downstream an input to be connected to the DC power source, an electronic current limiter configured to limit a current through the circuit to a maximum value if the current reaches this value, a fuse designed to open at a current value greater than the maximum value, a DC-to-DC converter configured to convert a DC input voltage to a lower nominal DC output voltage, a zener barrier having a zener voltage higher than the DC output voltage, and an output for connection to the electrical load.

Abstract: An intrinsically safe touch screen system includes a touch screen, a current limiting barrier coupled to the touch screen, a touch screen controller, and a voltage limiting barrier. The controller is coupled to the current limiting barrier, the voltage limiting barrier, and the touch screen, in a configuration such that signals transmitted to and from the touch screen will be within a level that ensures intrinsic safety of the touch screen.

Abstract: An intrinsically safe touch screen system includes a touch screen, a current limiting barrier coupled to the touch screen, a touch screen controller, and a voltage limiting barrier. The controller is coupled to the current limiting barrier, the voltage limiting barrier, and the touch screen, in a configuration such that signals transmitted to and from the touch screen will be within a level that ensures intrinsic safety of the touch screen.

Abstract: A system and method for providing an intrinsically safe (IS) circuit for driving a solenoid valve at a low power is disclosed. A voltage source generates a first voltage and is connected to a first side of the solenoid valve. A voltage inverter is connected to the voltage source and generates a second voltage from the first voltage. The second voltage is of opposite magnitude to the first voltage. A controller selectively controls the first voltage and the second voltage to be applied to the solenoid valve. In order to actuate the solenoid valve, the first voltage is applied to the first side of the solenoid valve and the second voltage is applied to the second side of the solenoid valve. In order to hold the solenoid valve in an on position, the first voltage is maintained and the second voltage is no longer applied to the second side of the solenoid valve.

Abstract: A system and method for providing an intrinsically safe (IS) circuit for driving a solenoid valve at a low power is disclosed. A voltage source generates a first voltage and is connected to a first side of the solenoid valve. A voltage inverter is connected to the voltage source and generates a second voltage from the first voltage. The second voltage is of opposite magnitude to the first voltage. A controller selectively controls the first voltage and the second voltage to be applied to the solenoid valve. In order to actuate the solenoid valve, the first voltage is applied to the first side of the solenoid valve and the second voltage is applied to the second side of the solenoid valve. In order to hold the solenoid valve in an on position, the first voltage is maintained and the second voltage is no longer applied to the second side of the solenoid valve.

Abstract: An electrical feed through for use in a high temperature oven such as the oven in a gas chromatograph. The feed through includes printed circuit boards which are maintained in compression to prevent the boards from physically separating at the elevated temperatures used in the oven. The structure that provides the compression also does not allow any flexure, torsional or longitudinal stress on the boards. The boards include an enhanced connector pad which is made from a continuous annular copper ring which is connected to all of the conductive layers of the board.