Pressure sensor systems for measuring a liquid pressure and deriving a liquid level from the measured pressure using gas pressure sensing devices. In one embodiment, liquid pressure results in compression or decompression of a trapped gas (as an example, air), wherein the gas pressure is detected by a gas pressure sensing device directly or a gas pressure sensing device that is protected inside a flexible pouch filled with a liquid. In another embodiment, a gas pressure sensing device is packaged in a flexible pouch filled with an inert liquid to protect the sensing device and circuit thereof from external contaminants while accurately transferring pressure from the liquid through a protective barrier. Application of such sensors in a wireless flood or a wireless liquid level measurement system is described as well.

An aerially controlled sludge level detection system is for determining a sludge level in a wastewater reservoir. The system may have a drone and a sludge level detection tool suspended from the drone. The drone may be operable to lower the sludge level detection tool into the wastewater reservoir and raise the sludge level detection tool out of the wastewater reservoir. The sludge level detection tool may have a longitudinally extending gauge. At least a portion of the gauge at a distal end may be hollow to allow a volume of a fluid and a volume of the sludge from within the wastewater reservoir to enter the gauge when lowered into the wastewater reservoir. The sludge level detection tool may also have an analyzer connected to the gauge for analyzing the volume of the fluid and the volume of the sludge within the gauge.

A level indicator with a cover that measures a water level, includes: a water level indicator that measures pressure; and a protective cover that surrounds the water level indicator. The protective cover includes a pressure transmitter that transmits pressure on an outside of the protective cover to an inside of the protective cover.

A method for determining a measurement error caused by a filling error, in particular the presence of gas bubbles, during measurement of the density of a liquid by means of a densimeter having a flexural resonator containing the liquid to be measured. During a measuring operation, a period duration of an oscillation of the flexural resonator induced by an induction unit is measured by a measuring device and the density of the liquid is determined by an evaluation unit.

A method for determining a measurement error caused by a filling error, in particular the presence of gas bubbles, during measurement of the density of a liquid by means of a densimeter having a flexural resonator containing the liquid to be measured. During a measuring operation, a period duration of an oscillation of the flexural resonator induced by an induction unit is measured by a measuring device and the density of the liquid is determined by an evaluation unit.

Disclosed herein are various techniques and devices for detecting a level of fluid within a fluid collection receptacle. These techniques and devices may further determine a flow rate of fluid entering the fluid collection receptacle or a volume of fluid collected within the fluid collection receptacle. Sensors, including pressure sensors, may be installed in, on, or within the fluid collection receptacle to detect information about the liquid within the receptacle including fluid level, flow rate, and volume.

Disclosed herein are various techniques and devices for detecting a level of fluid within a fluid collection receptacle. These techniques and devices may further determine a flow rate of fluid entering the fluid collection receptacle or a volume of fluid collected within the fluid collection receptacle. Sensors, including pressure sensors, may be installed in, on, or within the fluid collection receptacle to detect information about the liquid within the receptacle including fluid level, flow rate, and volume.

An apparatus for determining the identity and/or quantity of a liquid fuel contained in a fuel transporting tank of a fuel transporting vehicle can comprise: a longitudinally extensive member having a first end and a second end, an internal volume from which liquid fuel in the tank is excluded, and a mounting arrangement configured for mounting in use of the longitudinally extensive member within and in fixed relation to the tank, said second end configured in use to be immersed in the liquid fuel in the tank. The longitudinally extensive member can further comprise: first and second pressure sensors spaced apart by a fixed distance, each said pressure sensor having a face exposed in use to the local hydrostatic pressure of the liquid fuel in the tank; and a colour sensing device comprising a light emitter and a light detector configured to detect light from the emitter, said emitter and detector being arranged such that in use light from the emitter incident on the detector passes through said liquid fuel in the tank. The apparatus can further comprise a data processing device configured to determine the identity of the liquid fuel based on said pressure measurements from said first and second pressure sensors and colour data from said colour sensing device.

An apparatus for determining the identity and/or quantity of a liquid fuel contained in a fuel transporting tank of a fuel transporting vehicle can comprise: a longitudinally extensive member having a first end and a second end, an internal volume from which liquid fuel in the tank is excluded, and a mounting arrangement configured for mounting in use of the longitudinally extensive member within and in fixed relation to the tank, said second end configured in use to be immersed in the liquid fuel in the tank. The longitudinally extensive member can further comprise: first and second pressure sensors spaced apart by a fixed distance, each said pressure sensor having a face exposed in use to the local hydrostatic pressure of the liquid fuel in the tank; and a colour sensing device comprising a light emitter and a light detector configured to detect light from the emitter, said emitter and detector being arranged such that in use light from the emitter incident on the detector passes through said liquid fuel in the tank. The apparatus can further comprise a data processing device configured to determine the identity of the liquid fuel based on said pressure measurements from said first and second pressure sensors and colour data from said colour sensing device.

A sensor module includes a housing having a first cavity and a second cavity that are in communication with each other, a liquid level sensing module mounted on the housing and sensing liquid level related information when liquid flows into the second cavity, a turbidity sensing module mounted on a section of the housing having the first cavity, and a temperature sensing module integrated with the turbidity sensing module and sensing temperature related information of the liquid when the liquid flows into the first cavity. The turbidity sensing module includes a light transmitting unit and a light receiving unit that are located on opposite sides of the first cavity to allow light emitted from the light transmitting unit to pass through the first cavity and to be received by the light receiving unit.