A proximity detector includes a sensor providing a proximity reading. The proximity detector is capable of comparing the reading to a rising threshold level and a falling threshold level, wherein the falling threshold level is less than the rising threshold level. The proximity detector continuously stores a minimum reading value for the proximity reading. The proximity detector will report the presence of granular material only if the proximity reading remains less than the falling threshold level and within an epsilon value of the minimum reading value for a predetermined period of time.

An optical probe that measures the level of a liquid in a tank includes a transparent and refracting optical waveguide for receiving an injection of a collimated light beam. The optical waveguide internally reflects the collimated light beam according to a total reflection regime in any part of the optical waveguide located in a gaseous medium and refracts the collimated light beam according to a refraction regime in any part of the optical waveguide immersed in a liquid medium. The optical waveguide switches from the total reflection regime to the refraction regime at the interface between the gaseous medium and the liquid medium, and mirrors are arranged around said optical waveguide and reverse the path of a light beam collimated and refracted by the optical waveguide, the optical path covered by the collimated light beam representing the level of the liquid in the tank.

A sensor device for determining and/or monitoring a process variable of a medium in a container includes: a crystal body having at least one defect; and a magnetic field device for generating a magnetic field, the magnetic field device arranged such that a magnetic field can be generated in the region of the crystal body and in the region of the medium located within the container, so that a change of the magnetic field in the region of the crystal body is amplified, wherein the crystal body and the magnetic field device are arranged from the outside on a wall of the container. A method for determining and/or monitoring a process variable of a medium in a container using the sensor device is also disclosed.

A proximity detector includes a sensor providing a proximity reading. The proximity detector is capable of comparing the reading to a rising threshold level and a falling threshold level, wherein the falling threshold level is less than the rising threshold level. The proximity detector continuously stores a minimum reading value for the proximity reading. The proximity detector will report the presence of granular material only if the proximity reading remains less than the falling threshold level and within an epsilon value of the minimum reading value for a predetermined period of time.

A proximity detector includes a sensor providing a proximity reading. The proximity detector is capable of comparing the reading to a rising threshold level and a falling threshold level, wherein the falling threshold level is less than the rising threshold level. The proximity detector continuously stores a minimum reading value for the proximity reading. The proximity detector will report the presence of granular material only if the proximity reading remains less than the falling threshold level and within an epsilon value of the minimum reading value for a predetermined period of time.

An illumination system can be configured for use with a liquid level gauge. A mounting bracket can be configured to secure a LED assembly to a frost-proof extension of the liquid level gauge, with the LED assembly disposed adjacent to a second edge face of the frost-proof extension that is opposite a liquid tube. The LED assembly can be thereby configured to illuminate the liquid tube via the second edge face of the frost-proof extension.

The present invention relates to the technological field of meter systems and refers to a device for measuring the level of a fluid, especially, fuel fluids in vehicle tanks. The device in question including an optical guide having interaction surfaces and an light emitter element emitting light beams, an optical system including at least one collimator lens and a light diffuser, and at least one receiving element of the light beams, in which the information captured by the receiving element from the reflection reflected by the inclined interaction surfaces indicates the level of fluid stored in the reservoir. The inclined surfaces can have different angles (a), (), or an intermediate angle between (a) and ().

Disclosed is an apparatus and method for determining the liquid level of salvaged blood in a blood collection reservoir (11) of an autologous blood transfusion system (20), comprising sensing means (10, 12) for periodically sensing the liquid level of the salvaged blood in said blood collection reservoir (11) and outputting corresponding signals, and determining means (2) for determining the liquid level of the salvaged blood in said blood collection reservoir (11) based on said output signal of said sensing means. The sensing means comprises a plurality of light emitters (12) disposed on a first side of said blood collection reservoir (11) at different height levels (L1-L9) for emitting light and a plurality of light receivers (10) disposed at said different height levels (L1-L9) on a second side of said blood collection reservoir (11) opposite to said first side for sensing light emitted by said light emitters (12) and transmitted through said blood collection reservoir (11). Parameters of the optical set-up used for detection and signal analysis may be adjusted individually and dynamically so that disturbing effects caused e.g. by absorptive films on the inner surface of the blood collection reservoir (11) may be identified and prevented to thereby enhance the reliability of signal detection and analysis.

An apparatus for determining a value that represents an amount of liquid in a vessel, wherein the vessel is configured to be a tube or a cuvette. The vessel for the liquid is basically transparent, with at least one radiation unit, that is arranged alongside the longitudinal axis of the vessel and that radiates light into the vessel, as well as at least one light detector with at least one light receiver that is assigned to the radiation unit and that receives the light that is coming through the vessel and forwards it to the light detector. The apparatus comprises a data processing unit that determines the value that represents the amount of the liquid in the vessel from the light that was detected by the light detector. The apparatus is characterized in that the light detector detects the sum total of the light that was radiated through the vessel and was received by all light receivers. Furthermore, the invention relates to the use of the apparatus in an analyzer.

A liquid level sensing system provides a removable reservoir incorporating a reflective surface that can be interrogated by a stationary optical sensor in a receptacle receiving the removable reservoir. The optical sensor may detect the presence of the liquid within the reservoir without connection to the reservoir simplifying the process of making the reservoir removable while still allowing sensing of its contents. By aligning the optical axis with the insertion axis of the reservoir sensitive optical alignment problems are minimized.