Abstract: A photometer and a method of performing photometric measurements with this photometer are described. The photometer comprises a photodetector providing a detector signal corresponding to an intensity of light received by the photodetector; and measurement electronics including: an amplifier and a signal processing device configured to determine and to provide a measurement result based on a measurement signal determined by the signal processing device as or based on an amplified detector signal provided by the amplifier. The signal processing device is configured to determine the measurement signal: a) as or based on the amplified detector signal provided by the amplifier being a multistage amplifier including a transimpedance converter and a voltage to current amplifier; and/or b) in form of a noise reduced signal determined by subtracting a previously determined noise offset included in the amplified detector signal from the amplified detector signal.

Abstract: According to at least one aspect of the present disclosure, a method includes applying an alternating current having a frequency at a selected voltage to a sensor, wherein the voltage is applied between a reference electrode and a working electrode of the sensor, varying the frequency of the alternating current between a lower frequency and an upper frequency, measuring an impedance of the sensor between the reference electrode and the working electrode as a function of the frequency of the alternating current, analyzing the measured impedance to determine a total impedance of the sensor and the real and imaginary components of the total impedance at each applied frequency of the alternating current, and characterizing the sensor based on the total impedance at the low frequency end of the sensor and on the real and imaginary components of the total impedances.

Abstract: A method of and an apparatus for manufacturing a measuring cell comprising a tube having a first end capped by a membrane of an ion-selective material, comprising the steps of: providing a paste comprising all constituents of the ion-selective material; mounting the tube onto a stick with a tip such that the stick extends through the tube; dispensing an amount of the paste onto the tip; heating the first end of the tube and the dispensed paste to a temperature causing the dispensed paste to melt and the thus-produced melt to form a film covering the tip and an end surface of the first end of the tube; transforming the film into the membrane joined to the tube by cooling the first end of the tube and the film to a temperature below a melting point of the ion-selective material; and separating the thus-manufactured measuring cell from the stick.

Abstract: A method of manufacturing membranes consisting essentially of an ion-selective material is disclosed. The method comprises: providing a spreadable base material; dispensing a quantity of the base material onto a top side of a tray, wherein the top side includes a set of coplanar flat surface segments, each having a surface area corresponding to a disc area of one of the membranes to be manufactured, and wherein at least the top side of the tray consists essentially of a non-adhesive material; distributing the dispensed base material across the top side of the tray such that a thickness of the distributed base material covering the coplanar surface segments corresponds to a predetermined thickness; transforming the thus-distributed base material into ion-selective material comprising one or more coplanar sheets covering the coplanar surface segments; and removing individual membranes from the tray, each defining a disc-shaped section of the ion-selective material.

Abstract: According to at least one aspect of the present disclosure, a reference half-cell for an electrochemical sensor for measuring a medium is disclosed. The reference half-cell includes a housing defining a chamber containing an electrolyte, the housing including a wall having an aperture therethrough, and an electrode disposed in the electrolyte in the chamber. The reference half-cell further includes a reference junction disposed in the aperture such that an interface between the reference junction and the housing wall is impermeable. The reference junction is electrically or ionically conductive and impermeable to the measured medium and the electrolyte, and the reference junction enables a constant potential at the electrode. An electrochemical sensor and oxidation-reduction potential sensor employing the reference junction are also disclosed.

Abstract: According to at least one aspect of the present disclosure, a method includes applying an alternating current at a selected voltage to a sensor, wherein the voltage is applied between a working electrode and/or reference electrode of the sensor and a temperature sensor integrated into the sensor, varying the frequency of the alternating current between a lower frequency and an upper frequency, measuring an impedance of the sensor between the working electrode and/or reference electrode and the temperature sensor as a function of the frequency of the alternating current, and determining whether, based on the total impedance at the low frequency end of the sensor and on the real and imaginary components of the impedance, the insulations between working electrode and/or reference electrode and temperature sensor have a defect.

Abstract: According to at least one aspect of the present disclosure, a method includes applying an alternating current having a frequency at a selected voltage to a sensor, wherein the voltage is applied between a reference electrode and a working electrode of the sensor, varying the frequency of the alternating current between a lower frequency and an upper frequency, measuring an impedance of the sensor between the reference electrode and the working electrode as a function of the frequency of the alternating current, analyzing the measured impedance to determine a total impedance of the sensor and the real and imaginary components of the total impedance at each applied frequency of the alternating current, and characterizing the sensor based on the total impedance at the low frequency end of the sensor and on the real and imaginary components of the total impedances.

Abstract: A device for calibrating an in-line sensor is disclosed, including a housing having a first aperture and a second aperture arranged along an optical path extending through the housing, a first filter and a second filter disposed within the housing such that the filters are moveable from an operating position to a calibration position. In the calibration position the filters are arranged in the optical path and the housing includes a connection adjacent each of the first aperture and the second aperture, the connection structured to enable the housing to be reversibly attached to a flow cell, a detector and a light source of an in-line sensor.

Abstract: Light source for an inline sensor having one or more solid state UV emitters for emitting light at single wavelengths in the range of 240 to 400 nm. The light emitted by each of the emitters has a bandwidth on the order of 10-20 nm and is directed toward a measurement detector in the inline sensor. The UV emitters are enclosed in a housing which can be attached to the inline sensor, with a reference detector and a regulator for the UV emitters also within the housing, and an aperture through which the light passes from the emitters to the measurement detector. In some embodiments, air cooling is provided for the UV emitters.

Abstract: Light source for an inline sensor having one or more solid state UV emitters for emitting light at single wavelengths in the range of 240 to 400 nm. The light emitted by each of the emitters has a bandwidth on the order of 10-20 nm and is directed toward a measurement detector in the inline sensor. The UV emitters are enclosed in a housing which can be attached to the inline sensor, with a reference detector and a regulator for the UV emitters also within the housing, and an aperture through which the light passes from the emitters to the measurement detector.

Abstract: Micro volume inline optical sensor comprising a flowcell having a sample chamber which has a volume less than 0.4 mL and increases in diameter from two ends toward the middle, a flow passageway intersecting the chamber where the diameter is the greatest, monitoring ports with optically transmissive windows at the ends of the chamber, mounting rings on opposite sides of the flowcell disposed coaxially of an optical axis that passes through the monitoring ports and the sample chamber, and a light source and an optical detector mounted on the mounting rings in alignment with each other along the optical axis. In one embodiment, the sample chamber has a side wall with oppositely inclined frusto-conical sections, and the ends of the chamber are closed and sealed by the monitoring port windows and O-ring gaskets that surround the open ends and are compressed between the body of the flowcell and the windows.

Abstract: An apparatus includes a light emitting diode, a reference detector, and a control unit. The light emitting diode (LED) is configured to emit light along a beam path. The reference detector is configured to generate a signal characterizing an intensity of light emitted from the LED. The control unit coupled to the LED and is configured to selectively vary a driving current applied to the LED in response to the light detected by the reference detector and to maintain a substantially constant intensity of light emitted by the LED. Related apparatus, systems, techniques and articles are also described.

Abstract: Micro volume inline optical sensor comprising a flowcell having a sample chamber which has a volume less than 0.4 mL and increases in diameter from two ends toward the middle, a flow passageway intersecting the chamber where the diameter is the greatest, monitoring ports with optically transmissive windows at the ends of the chamber, mounting rings on opposite sides of the flowcell disposed coaxially of an optical axis that passes through the monitoring ports and the sample chamber, and a light source and an optical detector mounted on the mounting rings in alignment with each other along the optical axis. In one embodiment, the sample chamber has a side wall with oppositely inclined frusto-conical sections, and the ends of the chamber are closed and sealed by the monitoring port windows and O-ring gaskets that surround the open ends and are compressed between the body of the flowcell and the windows.

Abstract: Self-aligning light source and detector assembly having a sensor support mounted in a predetermined, fixed position, a light source holder mounted in a predetermined, fixed position relative to the sensor support, a sensor mounted in a fixed position on the sensor support, and a lamp assembly removably mounted to the light source holder in a predetermined position defined by mating surfaces which engage each other and seat the lamp assembly in the predetermined position whenever the lamp assembly is installed in the holder.

Abstract: Self-aligning light source and detector assembly having a sensor support mounted in a predetermined, fixed position, a light source holder mounted in a predetermined, fixed position relative to the sensor support, a sensor mounted in a fixed position on the sensor support, and a lamp assembly removably mounted to the light source holder in a predetermined position defined by mating surfaces which engage each other and seat the lamp assembly in the predetermined position whenever the lamp assembly is installed in the holder.

Abstract: Self-aligning light source and detector assembly having a sensor support mounted in a predetermined, fixed position, a light source holder mounted in a predetermined, fixed position relative to the sensor support, a sensor mounted in a fixed position on the sensor support, and a lamp assembly removably mounted to the light source holder in a predetermined position defined by mating surfaces which engage each other and seat the lamp assembly in the predetermined position whenever the lamp assembly is installed in the holder.

Abstract: Self-aligning light source and detector assembly having a sensor support mounted in a predetermined, fixed position, a light source holder mounted in a predetermined, fixed position relative to the sensor support, a sensor mounted in a fixed position on the sensor support, and a lamp assembly removably mounted to the light source holder in a predetermined position defined by mating surfaces which engage each other and seat the lamp assembly in the predetermined position whenever the lamp assembly is installed in the holder.

Abstract: Inline flow cell for use in monitoring multiple parameters in a sanitary process line, comprising a body with opposing end walls, a flow passageway extending along an axis between the end walls, and a plurality of side walls disposed tangentially about the axis, inlet and outlet fittings communicating with the passageway at the ends of the body for connecting the flow cell in a sanitary process line with fluid in the line flowing through the passageway, and monitoring ports opening through more than two of the side walls for receiving sensors for monitoring multiple parameters in the fluid.