The present invention relates to blood analysis. In order to determine the filling level of a cartridge, a device (10) is provided that comprises a cartridge interface (14) for receiving a cartridge and a liquid level sensor (16). A cartridge position guiding arrangement is configured to engage with the cartridge for providing a six degree-of-freedom constraint to the cartridge. The liquid level sensor comprises a light source (18) and a light detector (20). The light source is configured to provide a beam of light (22) incident upon a cavity surface (24) of an optical pit (26) of a cartridge received by the cartridge interface. The light detector is configured to detect a portion (28) of the beam of light reflected from the cavity surface of the optical pit. The device is configured to determine a filling level of the optical pit based on the detected portion of the beam of light.

A liquid cartridge includes a first surface, a second surface spaced apart from the first surface, and a third surface extending between the first surface and the second surface, with a liquid outlet through the first surface. A circuit board is mounted on the third surface. A locking mechanism includes a locking surface that extends above the third surface, and a liquid detection mechanism includes a light access portion. The light access portion is disposed between the circuit board and the locking surface, and the circuit board is disposed between the first surface and the light access portion.

A method of operating an electro-optic sensor includes disposing at least a portion of the electro-optic sensor in a liquid chamber, providing light from a light source of the electro-optic sensor at a first intensity, driving a light detector of the electro-optic sensor at a first sensitivity level, receiving, via the light detector, a first amount of light from the light source; determining whether liquid is present in the liquid chamber according to the first amount of light, providing light from the light source at a second intensity, driving the light detector at a second sensitivity level, receiving, via the light detector, a second amount of light from the light source, and/or confirming whether liquid is present in the liquid chamber according to the second amount of light. The first sensitivity level may be different from the second sensitivity level.

A beverage supply apparatus includes cooling device 6, milk tank 5 in storage chamber 6a of cooling device 6, and detection device 7 that detects the milk. Detection device 7 has first light guide body 7c to penetrate partition wall 12 having a multilayer box body that partitions storage chamber 6a, second light guide body 7d to penetrate partition wall 12 which faces first light guide body 7c, light projection unit 7a attached to partition-wall outer-surface-side end of first light guide body 7c to project light via the body 7c, and light receiving unit 7b attached to the partition-wall outer-surface-side end of second light guide body 7d to receive light transmitted through milk tank 5 via second light guide body 7d. The detection device detects the presence or absence of or the remaining amount of milk based on a light reception state in the light receiving unit 7b.

A liquid level detection system and a liquid level detection method comprising a light source, a light guiding medium, a photoelectric conversion receiver and a processing module is provided. The light guiding medium has an incident surface, a first reflection surface, and an exiting surface. The first reflection surface comprises a first sub-reflection surface and a second sub-reflection surface, with a liquid surface as a boundary line. When the light beam is incident on the first and second sub-reflection surfaces at the same angle, the refraction angle and light intensity loss is different, so there is an abrupt change in the generated light intensity image. The position of the abrupt change is the position of the liquid surface. The position of the liquid surface can thereby be obtained according to the position of abrupt change in light intensity after the light beam passes through the light guiding medium.

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.

A trap bowl is provided to accumulate liquid droplets from a filter, as a liquid content. The trap bowl includes a transparent vertical prism. The transparent vertical prism includes a face that forms a vertical transparent surface facing against a content of the section. The face can provide a first angle of total reflection when content of the section is a type of gas, and a second angle of total reflection when the content of the section is the liquid content. A light source may emit a light beam incident on the face at an angle of incidence. The angle of incidence results in reflection of the light beam, striking the light receiver, when the face has the first angle of total reflection, and results in refraction of the light beam, missing the light receiver, when the face has the second angle of total reflection.

An electro-optic liquid sensor may include a light source, a light detector, a prism, and a reflective optical member. The optical member may be arranged to reflect light emitted by the light source to the light detector when a liquid is disposed between the light source and the optical member. The electro-optic sensor may enable assessment of its operational state in the presence of liquid, thus improving on known electro-optic liquid sensors. A method of operating a sensor to assess the presence of liquid is disclosed.

A method of operating an electro-optic sensor includes disposing at least a portion of the electro-optic sensor in a liquid chamber, providing light from a light source of the electro-optic sensor at a first intensity, driving a light detector of the electro-optic sensor at a first sensitivity level, receiving, via the light detector, a first amount of light from the light source; determining whether liquid is present in the liquid chamber according to the first amount of light, providing light from the light source at a second intensity, driving the light detector at a second sensitivity level, receiving, via the light detector, a second amount of light from the light source, and/or confirming whether liquid is present in the liquid chamber according to the second amount of light. The first sensitivity level may be different from the second sensitivity level.

A liquid cartridge includes a first surface, a second surface spaced apart from the first surface, and a third surface extending between the first surface and the second surface, with a liquid outlet through the first surface. A circuit board is mounted on the third surface. A locking mechanism includes a locking surface that extends above the third surface, and a liquid detection mechanism includes a light access portion. The light access portion is disposed between the circuit board and the locking surface, and the circuit board is disposed between the first surface and the light access portion.