A fluid reservoir (101) includes a number of electrode pairs disposed within the fluid reservoir. Each of the electrode pairs includes a number of sensing electrodes (103), and a number of electrical traces (105) wherein the sensing electrodes are coupled to a respective one of the electrical traces. The fluid reservoir also includes a common electrode (104) electrically coupled to a voltage source (106). A number of properties of a fluid (110) within the fluid reservoir are detected by applying a voltage between the sensing electrodes in an electrode pair, and a level of the fluid within the fluid reservoir is detected by applying a voltage between the electrodes and the common electrode. A multiplexer (102) may be used to selectively couple the sensing electrodes (103) to a processing device (108). The fluid reservoir may be a printing fluid container.

A fluid reservoir may include a number of metal traces along a wall of the fluid reservoir, and a number of fuse circuits along a length of the metal traces. Each of the fuse circuits may include a fuse along a length of a respective metal trace, and a number of parasitic resistive elements in parallel to the fuse. The parasitic resistive elements reduce current flow through the fuse in the presence of a fluid contained within the fluid reservoir.

A liquid level measurement circuit includes: a probe, a reference electrical signal module and a potential conversion module, where the probe extends into a liquid level accommodation body, and the liquid level accommodation body accommodates a measurement liquid module. If the liquid level of said liquid is lower than a preset liquid level, a positive electrode conductor and/or a negative electrode conductor are/is not immersed in the measurement liquid, and an output end of the potential conversion module outputs a first electrical signal; and if the liquid level of the measurement liquid is not lower than the preset liquid level, the positive electrode conductor and the negative electrode conductor are immersed in the measurement liquid, and the output end of the potential conversion module outputs a second electrical signal. The accuracy of liquid level measurement can be improved.

Embodiments generally relate to froth measurement apparatus, and related methods and systems. An example apparatus comprises: an elongate first housing portion; and a series of sensor probes positioned along the first housing portion, each of the sensor probes having a probe body extending away from the first housing portion by a distance and comprising first and second electrodes for measuring changes in electrical potential associated with froth and/or bubbles. The sensor probes comprise signal processing circuitry coupled to the probe bodies to receive analog output signals from the probe bodies and to generate digital output signals based on the analog output signals. The apparatus comprises at least one processor configured to receive the digital output signals or sensor information based on the digital output signals and configured to determine at least one froth parameter over a sampling period based on the digital output signals or the sensor information.

A fluid reservoir (101) includes a number of electrode pairs disposed within the fluid reservoir. Each of the electrode pairs includes a number of sensing electrodes (103), and a number of electrical traces (105) wherein the sensing electrodes are coupled to a respective one of the electrical traces. The fluid reservoir also includes a common electrode (104) electrically coupled to a voltage source (106). A number of properties of a fluid (110) within the fluid reservoir are detected by applying a voltage between the sensing electrodes in an electrode pair, and a level of the fluid within the fluid reservoir is detected by applying a voltage between the electrodes and the common electrode. A multiplexer (102) may be used to selectively couple the sensing electrodes (103) to a processing device (108). The fluid reservoir may be a printing fluid container.

A method and an apparatus for monitoring a set fill level of a medium in a container using a fill level measuring probe that is designed to operate as a conductive fill level measuring probe in a conductive operating mode and as a capacitive fill level measuring probe in a capacitive operating mode, with a control/evaluation/output unit that is designed to alternately trigger conductive operating mode and capacitive operating mode, and with a control/evaluation/output unit that determines whether the set fill level of the medium in the container has been reached on the basis of the measured values from the two operating modes, and which generates a message when the set fill level is exceeded and/or undershot.

A liquid level meter includes a first resistive temperature detector; a first temperature measuring body a liquid level detection section a temperature detection section detecting the temperatures of the first resistive temperature detector and the first temperature measuring body; a current control section determining a value of a current to apply to the first resistive temperature detector such that a difference between the temperatures of the first resistive temperature detector and the first temperature measuring body detected by the temperature detection section to be a first constant value; and a power supply unit supplying a current of the determined current value to the first resistive temperature detector; wherein the liquid level detection section determines whether the first resistive temperature detector is present in a liquid or outside of the liquid using the value of the current applied to the first resistive temperature detector.

Method and apparatus are disclosed for fuel fill volume estimation for a vehicle. An example vehicle includes a fuel tank float, a dashboard display, and an engine control module. The engine control module divides a fuel tank into zones. When the vehicle is not in motion and a position of the fuel tank float changes by a threshold amount, engine control module measures an initial fuel level. When the position of the fuel tank float does not change for a threshold period of time, the engine control module measures a final fuel level. Additionally, the engine control module calculates an amount of fuel added to the fuel tank based on the zones associated with the initial fuel level and a final fuel level and display the amount on the dashboard display.

Method and apparatus are disclosed for fuel fill volume estimation for a vehicle. An example vehicle includes a fuel tank float, a dashboard display, and an engine control module. The engine control module divides a fuel tank into zones. When the vehicle is not in motion and a position of the fuel tank float changes by a threshold amount, engine control module measures an initial fuel level. When the position of the fuel tank float does not change for a threshold period of time, the engine control module measures a final fuel level. Additionally, the engine control module calculates an amount of fuel added to the fuel tank based on the zones associated with the initial fuel level and a final fuel level and display the amount on the dashboard display.

A potassium nitrate level detection sensing module M in a strengthening furnace according to the present invention includes a level detection means, which is installed inside a glass strengthening furnace, installed at a height equal to a level line of strengthening liquid to be filled in the strengthening furnace F, and generates an electrical signal having a set threshold or more or an electrical signal having the set threshold or less when it comes into contact with the strengthening liquid and detects that the strengthening liquid filled in the glass strengthening furnace F has reached a set strengthening liquid level line. The potassium nitrate level detection sensing module in the strengthening furnace according to the present invention having such a configuration can automatically identify that potassium nitrate in a liquid state, which is melted in the strengthening furnace, has reached the set level line in the strengthening furnace.