A system for detecting a characteristic of a fluid. In one example, the system includes a tube, a float, a sensor, and a controller. The tube is configured to receive the fluid. The float is located within the tube. The sensor is configured to sense a position of the float. The controller is configured to receive, from the sensor, the position of the float, and determine a characteristic of the fluid based on the position of the float. The characteristic may be a density or a concentration.

A hydrometer device according to an example includes a floating waterproof device container, and a liquid level sensor positioned in the device container to sense an immersion level of the device container when the device container is floating in a container of liquid. The hydrometer device further includes a conversion circuit positioned in the device container to convert the sensed immersion level to a digital value, and a controller positioned in the device container to determine a liquid density value for the liquid based on the digital value.

A hydrometer device according to an example includes a floating waterproof device container, and a liquid level sensor positioned in the device container to sense an immersion level of the device container when the device container is floating in a container of liquid. The hydrometer device further includes a conversion circuit positioned in the device container to convert the sensed immersion level to a digital value, and a controller positioned in the device container to determine a liquid density value for the liquid based on the digital value.

A density meter for measuring the density of a fluid, having a base plate, wherein a spring element is clamped to the base plate; a torpedo, wherein the torpedo comprises a known weight, and wherein the torpedo is attached or coupled to the spring element; and a sensor, wherein the sensor measures a deflection of the spring element, as the torpedo displaces a volume of fluid.

A method of testing for a desired specific gravity of a liquid. The method including the use of a temperature calibration gauge and a hydrometer. The temperature calibration gauge has a thermo sensing end and a readout indicating the desired hydrometer reading at the current temperature of the liquid. The method includes the steps of contacting the thermo sensing end and the hydrometer with the liquid and comparing the readout of the temperature calibration gauge with the measurement indicated by the hydrometer.

A method of testing for a desired specific gravity of a liquid. The method including the use of a temperature calibration gauge and a hydrometer. The temperature calibration gauge has a thermo sensing end and a readout indicating the desired hydrometer reading at the current temperature of the liquid. The method includes the steps of contacting the thermo sensing end and the hydrometer with the liquid and comparing the readout of the temperature calibration gauge with the measurement indicated by the hydrometer.

A digital hydrometer and methods of digitally displaying a specific gravity measured by a hydrometer are provided. The digital hydrometer can comprise a base, a displacement vessel, an inductive distance sensor, an output circuit, and a hydrometer float. The displacement vessel and inductive distance sensor can be mounted in or on the base. The displacement vessel can hold a displacement fluid. The hydrometer float can float in the displacement fluid. The output circuit can be in electrical communication with the inductive distance sensor and comprise a digital display device configured to display a digital value that is commensurate with a change in impedance attributable to the proximity of a metallic object, in the hydrometer float, to the sensor or its inductor. The digital value can be a specific gravity of the displacement fluid.

A digital hydrometer and methods of digitally displaying a specific gravity measured by a hydrometer are provided. The digital hydrometer can comprise a base, a displacement vessel, an inductive distance sensor, an output circuit, and a hydrometer float. The displacement vessel and inductive distance sensor can be mounted in or on the base. The displacement vessel can hold a displacement fluid. The hydrometer float can float in the displacement fluid. The output circuit can be in electrical communication with the inductive distance sensor and comprise a digital display device configured to display a digital value that is commensurate with a change in impedance attributable to the proximity of a metallic object, in the hydrometer float, to the sensor or its inductor. The digital value can be a specific gravity of the displacement fluid.

A liquid density measuring device for use with a hydrometer comprising a vessel for receiving a liquid sample with a temperature calibration gauge having a thermo sensing end in contact with the liquid sample within the vessel. The gauge including a readout can be either analog or digital. The readout indicates a number relative to a current temperature of the liquid sample as sensed by the gauge. The number indicated on the readout being a desired hydrometer reading at the current temperature of the liquid sample. The readout will change to indicate a different desired hydrometer reading if the liquid sample changes temperature.

A liquid density measuring device for use with a hydrometer comprising a vessel for receiving a liquid sample with a temperature calibration gauge having a thermo sensing end in contact with the liquid sample within the vessel. The gauge including a readout can be either analog or digital. The readout indicates a number relative to a current temperature of the liquid sample as sensed by the gauge. The number indicated on the readout being a desired hydrometer reading at the current temperature of the liquid sample. The readout will change to indicate a different desired hydrometer reading if the liquid sample changes temperature.