A testing device and method for floating rate of floating agent for fracture height control are provided. The test device includes a support frame, a glass tube vertically fixed on the support frame, a floating agent storage container, a control valve, and a liquid storage tank, wherein multiple circular holes are uniformly distributed along an axial direction of the glass tube, and multiple turbidimeters for measuring liquid turbidity are sequentially mounted on the circular holes. The liquid storage tank communicates with an inner cavity of an upper end of the glass tube through a pipeline, and the floating agent storage container is connected to an inner cavity of a lower end of the glass tube through a control valve. The present invention increases accuracy of measured floating rate of the floating agent, and provides reliable floating data of the floating agent for oil and gas reservoir reconstruction.

A method and device are disclosed for fuel-detection by a fuel sending unit by placing a fuel sending unit in a first position from a second position, and releasing the fuel sending unit from the first position such that a buoyancy characteristic of a fuel sending unit float prompts the fuel sending unit to the second position. A rate-of-travel of the fuel sending unit is sensed from the first position to the second position to produce fluid travel data, wherein the rate-of-travel being affected by a fuel density. Fluid-type identification data may be generated based on the fluid travel data.

A method and device are disclosed for fuel-detection by a fuel sending unit by placing a fuel sending unit in a first position from a second position, and releasing the fuel sending unit from the first position such that a buoyancy characteristic of a fuel sending unit float prompts the fuel sending unit to the second position. A rate-of-travel of the fuel sending unit is sensed from the first position to the second position to produce fluid travel data, wherein the rate-of-travel being affected by a fuel density. Fluid-type identification data may be generated based on the fluid travel data.

Subsea equipment-protection apparatus including a fluid monitoring apparatus for detecting a first fluid, a second fluid and a third fluid. The fluid monitoring apparatus including a first float having a density less than that of the first fluid but greater than that of the second fluid; a second float having a density less than that of the second fluid but greater than that of the third fluid; and a sensor configured to detect the first and second floats so that the position of the floats can be determined. The first float floating when a fluid with density greater than the first float is present and sinking when a fluid with density less than the first float is present. The second float floating when a fluid with a density greater than the second float is present and sinking when a fluid with a density less than the second float is present.

Subsea equipment-protection apparatus including a fluid monitoring apparatus for detecting a first fluid, a second fluid and a third fluid. The fluid monitoring apparatus including a first float having a density less than that of the first fluid but greater than that of the second fluid; a second float having a density less than that of the second fluid but greater than that of the third fluid; and a sensor configured to detect the first and second floats so that the position of the floats can be determined. The first float floating when a fluid with density greater than the first float is present and sinking when a fluid with density less than the first float is present. The second float floating when a fluid with a density greater than the second float is present and sinking when a fluid with a density less than the second float is present.

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.

Provided is a downhole tool and a well system. The downhole tool, in one aspect, includes a tubular providing one or more production fluid flow paths for a production fluid. The downhole tool, according to this aspect, further includes one or more float chambers located within the tubular, and two or more floats located within the one or more float chambers. In one aspect, a first of the two or more floats has a first density (.sub.1) between a density of gas (.sub.g) and a density of oil (.sub.o), and a second of the two or more floats has a second density (.sub.2) between the density of oil (.sub.o) and a density of water (.sub.w). The downhole tool, according to this aspect, further includes two or more non-contact proximity sensors configured to sense a radial location of the two or more floats to determine a gas:oil ratio and oil:water ratio.

Provided is a downhole tool and a well system. The downhole tool, in one aspect, includes a tubular providing one or more production fluid flow paths for a production fluid. The downhole tool, according to this aspect, further includes one or more float chambers located within the tubular, and two or more floats located within the one or more float chambers. In one aspect, a first of the two or more floats has a first density (.sub.1) between a density of gas (.sub.g) and a density of oil (.sub.o), and a second of the two or more floats has a second density (.sub.2) between the density of oil (.sub.o) and a density of water (.sub.w). The downhole tool, according to this aspect, further includes two or more non-contact proximity sensors configured to sense a radial location of the two or more floats to determine a gas:oil ratio and oil:water ratio.

A system and method are disclosed for differentiating sugar-free and regular carbonated beverages. The system and method exploit the difference in specific gravity of fluid materials by observing calibrated beads immersed in fluids.

A sample to be measured is placed in a medium solution between two circular magnets to ensure that the sample to be measured is levitated in a set circular area between the two circular magnets, and a levitation position of the sample to be measured in the magnetic field is measured. The density of the sample is calculated according to formula (I): ${?}_s={?}_m+\frac{{?}_m-{?}_s}{g{?}_0}\left(B_r\frac{?B_z}{?r}+B_z\frac{?B_z}{?z}\right).$
Compared to the prior art, the method of the present disclosure provides a novel method for measuring a density of a substance, in which the involved device is easy to operate and has low cost, and the measurement results are easy to observe and have high accuracy.