A fluid level sensing device includes a substrate (210) and a sensing die (216) cantilevered at one end from the substrate. A number of sensing components (218), preferably thermal or impedance sensing components, are disposed on the sensing die and detect a fluid level in a fluid reservoir. A protective member (208) is also cantilevered at one end from the substrate alongside the sensing die. Electrical interconnects (212) output data collected from the number of sensing components. A number of sensing dies may be provided to lengthen the sensing device, in which case the protective cover extends alongside and parallel to the number of sensing dies.

A vehicular liquid containment system including a tank, a pressure sensor arranged to detect a pressure in a vapor dome inside the tank, at least two thermistors configured to detect temperatures at a plurality of levels of the tank, and leak detection logic operatively connected to the pressure sensor and the thermistors. The leak detection logic is configured to: use a first thermistor of the thermistors to perform a first measurement indicative of a temperature in the vapor dome in the tank; estimate an expected pressure evolution in function of at least the first temperature measurement; monitor pressure sensed by the pressure sensor, determine whether the monitored pressure deviates from the expected pressure evolution, and generate a leak condition signal conditional on the determining.

An apparatus and method for measuring the level of a liquid. The apparatus comprises an elongated, thermally conductive probe with an upper region to be disposed above the surface of the liquid, a lower region to be disposed below the surface of the liquid, and a middle region. A heater adds heat to the probe, and temperature sensors may measure the temperature of the probe in the upper and lower regions. An actuator may introduce a vibration into the probe at a first location, and a vibration sensor senses the arrival of the vibration at a second location. Electrical circuitry controls may be used to receive signals and make measurements. The liquid level may be computed by electrical circuitry controls via an equation.

A detector configured to indirectly monitor a level of liquid within a container is provided. The detector includes a temperature sensor and a heat producing element proximate to the temperature sensor. A shell is disposed around the temperature sensor and heat producing element, the shell is configured to be disposed within a container and to provide a barrier between liquid disposed within the container and each of the temperature sensor and heat producing element. The heat producing element is configured to transfer heat generated therein to the shell, and the sensor is configured to measure a surface temperature of the heat producing element.

A kit for connecting to, and monitoring fill levels of a fluid storage tank includes a control module and primary and secondary sensor units. The control module is electronically connected to the primary sensor unit. The control module includes a circuit board with a microprocessor, memory unit, and transmitter. Each sensor unit includes a housing a seal attached to the housing around an opening thereof, attachment structure for attaching the housing to a wall of the tank, and an infrared sensor disposed in the housing proximate the opening. The primary sensor unit also includes a circuit board disposed within the housing, an ambient temperature sensor disposed in the housing, and a communications link for communicating with the control module. A method of monitoring a fluid level in a storage tank, and a system for monitoring and reporting fluid levels in a plurality of storage tanks, are also described.

A method of forming a fluid level sensor includes coupling an array of heating elements and sensors to a first side of a substrate. A second side of the substrate is coupled to a carrier. The method also includes coupling an electrical interface to the carrier and electrically coupling the array to the electrical interface via a conductive wire. The method further includes overmolding the electrical interface, the first side of the substrate, and the conductive wire to form an overmolded fluid level sensor. The carrier may be coupled to the second side of the substrate and the electrical interface via a releasable adhesive and may be removed after overmolding the fluid level sensor.

Systems and methods for storing fluid are described. In some embodiments, a system may include a container having an internal volume that is configured to change as fluid enters or exits, a first shell component, and a second shell component. The first shell component may limit an expansion of the container in a first direction, and the second shell component may limit the expansion of the container in a second direction that is opposite the first direction.

A pump assembly with at least one liquid space (32) in an interior. The liquid space (32) contains a liquid or is configured for receiving a liquid. A sensor (34, 42) is arranged in the liquid space (32), which sensor is configured to detect at least one material property of the liquid located in the liquid space (32). A filter element (44) is arranged in the interior of the liquid space (32) such that the filter element (44) shields the sensor (34, 42) with respect to the surrounding liquid space (32), the filter element (44) being permeable to the liquid. A method for controlling a pump assembly is also provided.

A liquid level detector includes: a vertically-mounted accumulator that stores refrigerant; a heater that heats the accumulator; a temperature detector that detects a surface temperature of the accumulator; a pressure detector that detects a pressure of the refrigerant in the accumulator; and a controller. The controller detects a position of a liquid surface of the refrigerant in the accumulator based on a surface temperature of the accumulator detected by the temperature detector when the accumulator is heated by the heater, and a pressure of the refrigerant in the accumulator detected by the pressure detector.

An example printing cartridge includes a fluid container, a sensing die including a plurality of sensing locations in thermal contact with the fluid container, and a voltage comparator to output time-based information by comparing a sensed voltage generated at a selected sensing location of the plurality of sensing locations to a threshold voltage, the time-based information representative of whether a fluid is present at the sensing location.