An apparatus for determining a vertical level or density of a material column including one or more of a granular solid, a wet granular solid, a slurry, and a suspension, the apparatus having a support member; and at least one measurement module, wherein the measurement module includes a support arm mounted to the support member and extending outwardly from the support member; a displacer mounted to the support arm, and a force measurement device configured to measure a force attributable to a mass of the displacer mediated by a buoyancy of the displacer in the material column, wherein the measurement module has a data connection to a data processing unit for transmitting measurement data from the measurement module to the data processing unit to generate level or density information about the material column.

An apparatus for determining a vertical level or density of a material column including one or more of a granular solid, a wet granular solid, a slurry, and a suspension, the apparatus having a support member; and at least one measurement module, wherein the measurement module includes a support arm mounted to the support member and extending outwardly from the support member; a displacer mounted to the support arm, and a force measurement device configured to measure a force attributable to a mass of the displacer mediated by a buoyancy of the displacer in the material column, wherein the measurement module has a data connection to a data processing unit for transmitting measurement data from the measurement module to the data processing unit to generate level or density information about the material column.

A viscometer includes first and second capillaries and a valve. In a first state, the valve connects the second capillary to a first fluid injector via the first capillary. In a second state, the valve connects the second capillary to a second fluid injector. A controller receives data indicative of respective pressure drops within the first and second capillaries, and generates a pressure ratio signal therefrom. The controller analyzes the pressure ratio signal to determine an end of a transition between a first equilibrium when the valve is in the first state, and a second equilibrium when the valve is in the second state. The controller defines a measurement window based on the transition end, and therein determines a viscosity of the second fluid based on the pressure ratio signal. The first fluid is a solvent, and the second fluid is a solution of a same solvent and a solute.

A specific gravity measurement apparatus has a specific gravity hydrometer that carries a codestrip at the top. A linear optical encoder is disposed to view the codestrip and to output electronic signals that are indicative of a movement of the codestrip relative to said encoder. The movement is indicative of a change in the specific gravity of the liquid, such as a change in a salinity of the aquarium water in which the hydrometer floats. The measurement apparatus may be incorporated into a saltwater aquarium salinity control system where an electronic controller uses the measurement inputs to control a plurality of pumps for selectively adding saltwater or freshwater to the aquarium water in order to control the salinity of the water at a given setpoint level.

A specific gravity measurement apparatus has a specific gravity hydrometer that carries a codestrip at the top. A linear optical encoder is disposed to view the codestrip and to output electronic signals that are indicative of a movement of the codestrip relative to said encoder. The movement is indicative of a change in the specific gravity of the liquid, such as a change in a salinity of the aquarium water in which the hydrometer floats. The measurement apparatus may be incorporated into a saltwater aquarium salinity control system where an electronic controller uses the measurement inputs to control a plurality of pumps for selectively adding saltwater or freshwater to the aquarium water in order to control the salinity of the water at a given setpoint level.

A method for determining the density of an at least flowable, in particular liquid, specimen with a rheometer, in particular a rotational rheometer, includes providing the rheometer with a first measurement component for receiving the at least flowable, in particular liquid, specimen, and a second measurement component with a known volume to be immersed into the specimen. The first and second measurement components are movable relative to one another. The perpendicular force between the two measurement components is measured after the immersion of the second measurement component into the specimen. The measured perpendicular force corresponds to the buoyancy force acting between the specimen and the second measurement component. The density of the specimen is calculated based on Archimedes' principle by reference to the known volume of the second measurement component and the measured perpendicular force. A rheometer for carrying out the method is also provided.

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 viscometer includes first and second capillaries and a valve. In a first state, the valve connects the second capillary to a first fluid injector via the first capillary. In a second state, the valve connects the second capillary to a second fluid injector. A controller receives data indicative of respective pressure drops within the first and second capillaries, and generates a pressure ratio signal therefrom. The controller analyzes the pressure ratio signal to determine an end of a transition between a first equilibrium when the valve is in the first state, and a second equilibrium when the valve is in the second state. The controller defines a measurement window based on the transition end, and therein determines a viscosity of the second fluid based on the pressure ratio signal. The first fluid is a solvent, and the second fluid is a solution of a same solvent and a solute.

A viscometer includes first and second capillaries and a valve. In a first state, the valve connects the second capillary to a first fluid injector via the first capillary. In a second state, the valve connects the second capillary to a second fluid injector. A controller receives data indicative of respective pressure drops within the first and second capillaries, and generates a pressure ratio signal therefrom. The controller analyzes the pressure ratio signal to determine an end of a transition between a first equilibrium when the valve is in the first state, and a second equilibrium when the valve is in the second state. The controller defines a measurement window based on the transition end, and therein determines a viscosity of the second fluid based on the pressure ratio signal. The first fluid is a solvent, and the second fluid is a solution of a same solvent and a solute.