Systems and methods for pressure measurement
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsAaron Wiest, Dylan R. Switzer, Craig MacDougall, Llewelynn R. Galace
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Abstract
Apparatus, systems, and methods of measuring relative pressure based on the displacement of a Cartesian diver are provided. Within the system, various designs of divers, as well as a variety of measurement methods implementing such systems and apparatus, are illustrated. The systems and methods described herein are directed to precise pressure measurements traceable to the SI through the vertical displacement of a ludion within a two fluid system. The system is selectively optimized to ensure the buoyancy and mass of the ludion as well as the density of the gases and fluids involved are known and controlled.
Claims24
A pressure measuring apparatus comprising:
- a container having one or more sealable ends defining an internal volume configured to receive at least a first and a second fluid such that the first fluid has a density less than the density of the second fluid wherein a first portion of the internal volume is filled with the first and second fluids such that the first and second fluids are separated by a boundary interface and wherein a second portion of the internal volume is filled with a first compressible gas disposed above the first fluid;
- a vessel having at least one non-sealable opening and at least one sealable portion defining an internal cavity, the vessel being disposed in a downward direction within the internal volume of the container such that the at least one non-sealable opening is disposed in a downward direction and configured to receive at least a portion of the second fluid such that a first portion of the internal cavity is filled with the second fluid and a second portion is filled with a second compressible gas such that the vessel is buoyantly positioned between the first and second fluids, and the boundary interface intersects the vessel at a first pressure, and wherein a change in the environmental pressure of the first compressible gas is communicated to the first and second fluids and the second compressible gas such that as the environmental pressure changes the volume of the second compressible gas changes causing vertical movement of the vessel within the two fluids;
- a precision measurement device configured to measure the movement of the vessel within the two fluids;
- and
- a measurement translation device in communication with the precision measurement device and configured to receive a movement input data from the measurement device and translate the movement input data to a physical parameter.
A method for measuring pressure comprising:
- providing a container having one or more sealable ends defining an internal volume;
- disposing at least a first and a second fluid within the internal volume, wherein the first fluid has a density less than the density of the second fluid, such that a first portion of the cavity is filled with the first and second fluids, such that the first and second fluids are separated by a boundary interface, and wherein a second portion of the cavity is filled with a first compressible gas disposed above the first fluid;
- placing a vessel having at least one non-sealable opening and at least one sealable portion defining an internal cavity within the first container in a configuration such that the at least one non-sealable opening is disposed in a downward direction;
- filling a portion of the vessel with a second compressible gas such that the vessel is buoyantly positioned between the first and second fluids such that the boundary line intersects the vessel at a first pressure;
- inducing a change in pressure on the first compressible gas such that the pressure exerted on the first fluid is changed and said pressure change is translated to the second compressible gas through the second fluid thereby changing the volume of space within the portion of the vessel occupied by the second compressible gas, such that the vessel changes position within the first and second fluids relative to the boundary interface;
- measuring the movement of the vessel within the first and second fluids disposed within the internal volume;
- and
- translating the measured movement from the measuring device to a pressure change.
Dependencies are inferred from the claim text.