Miniature wireless concentration meter
Inventors
Barber, Jeffrey • Weatherall, James C. • Karns, Duane • Smith, Barry T.
Assignees
US Department of Homeland Security
Publication Number
US-11761870-B2
Publication Date
2023-09-19
Expiration Date
2042-05-27
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Abstract
A device to determine density includes a housing, a first transducer disposed in the housing at a first position, and a second transducer disposed in the housing at a second position. The second transducer is located a distance from the first transducer. The device also includes a controller that reads a first output from the first transducer, and reads a second output from the second transducer. The controller determines a density of a liquid based on the first output, the second output, and the distance.
Core Innovation
The invention is a miniature wireless density meter designed as a compact capsule package that includes at least two transducers positioned at fixed distances within a housing. The device contains a controller that reads outputs from these transducers and determines the density of a liquid based on these readings and the known distance between the transducers. The meter can use transducers such as ultrasonic or pressure sensors, and may include temperature sensing to adjust for thermal effects and improve accuracy. The device is capable of operating while submerged or floating in liquid, even under motion such as a rotating evaporating flask.
The problem addressed is the limitation of existing density meters, which are often large, require liquid to be drawn through sampling hoses, disturb the liquid, or fail to distinguish between liquids with similar dielectric constants. These limitations make them unsuitable for measuring densities of hazardous or high-concentration chemicals such as hydrogen peroxide solutions or mixtures where components have similar dielectric properties. The invention solves this by providing a small, wireless, and non-intrusive device capable of accurate density measurements in situ without disturbing liquid or removing it from its container.
The invention further includes variations such as a device with a transducer and reflector for reflection measurements, and a device with a wedge structure having multiple facets to couple transducers at various angles of incidence. The controller can wirelessly transmit measurement data externally, enabling remote monitoring and control. The device's design allows it to fit through narrow openings, maintain orientation due to buoyancy or weight distribution, and operate effectively during processes such as distillation, providing real-time density and concentration information.
Claims Coverage
The claims cover four independent inventive features related to devices for determining liquid density using different transducer configurations and measurement methods.
Density determination using first and second transducers with transmission measurement along a channel
A device comprising a housing with an outward-facing channel accommodating a first and second transducer spaced by a distance with a direct unobstructed line of sight. A controller reads outputs from these transducers and determines liquid density based on a transmission measurement of time-of-flight information, factoring in the bulk modulus and density of the liquid. The device is buoyant to position transducers at different depths.
Density determination using a transducer and a reflector with transmission measurement along a channel
A device comprising a housing with an outward-facing channel containing a transducer and a reflector spaced by a distance with a direct unobstructed line of sight. The controller reads output from the transducer and determines the liquid density based on a transmission measurement of time-of-flight information, considering bulk modulus and density, with buoyancy positioning transducer and reflector at different depths.
Density determination using multiple transducers coupled to a wedge structure at various angles
A device including a housing coupled to a wedge structure with an exposed surface contacting the liquid and multiple facets. First and second transducers couple to different facets at distinct angles of incidence, with a controller reading outputs from these transducers to determine liquid density based on their interaction with the wedge/liquid interface.
Density measurement device with transducers in an outward-facing channel and wireless transmission capability
A device comprising a housing with an outward-facing channel admitting liquid, first and second transducers spaced by a known distance with unobstructed line of sight along the channel, and a controller reading outputs corresponding to transmission measurements. The controller directs a transceiver to wirelessly transmit these measurements through the liquid to an external receiver for density determination, with buoyancy positioning the transducers at different depths.
The claims define various configurations of the density meter device featuring transducers positioned to perform transmission or reflection measurements within a channel or coupled to a wedge, employing time-of-flight data and physical spacing to determine liquid density, and including features such as wireless communication, temperature compensation, buoyancy-based positioning, and capability to monitor concentration changes during distillation.
Stated Advantages
Provides a compact, miniature device that can be inserted through small openings such as evaporating flask joints.
Enables wireless data transmission through liquid to an external receiver for remote monitoring.
Operates reliably in motion environments, such as rotating containers, without disturbing the liquid or requiring liquid removal.
Employs multiple transducers and configurations to measure density accurately even for liquids with similar dielectric constants, such as hydrogen peroxide solutions.
Allows real-time monitoring of liquid density and composition during processes like distillation, enabling automated process control.
Includes temperature sensing and compensation to correct for thermal expansion and temperature-dependent liquid properties.
Customizable buoyancy and shape to position the device as desired within liquid containers, floating or sinking as required.
Documented Applications
Monitoring concentration of hydrogen peroxide solutions during synthesis and distillation processes.
Use inside evaporating flasks of rotary evaporators to measure liquid density without interrupting distillation.
Determining concentrations of chemical ingredients such as nitric acid, urea nitrate, ethanol, and salt in aqueous solutions.
Facilitating safe and efficient chemical synthesis and evaluation, including detection and testing related to explosives.
Measuring density and concentration changes in liquids involved in brewing, winemaking, or other related industries.
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