Device and method for measuring the rheological properties of a yield stress fluid
Inventors
Samaniuk, Joseph R. • Klingenberg, Daniel J. • Scott, Charles T. • Root, Thatcher W.
Assignees
US Department of Agriculture USDA • Wisconsin Alumni Research Foundation
Publication Number
US-9116092-B2
Publication Date
2015-08-25
Expiration Date
2031-10-07
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Abstract
A device and a method are provided for measuring the yield stress of a fluid. The device includes a container for receiving the fluid therein and an auger having a shaft extending along an axis and a helical flange extending radially about the shaft. The auger is movable in the fluid between a first position and a second position. A sensor is operatively connected to the auger. The sensor measures a force on the auger as the auger moves from the first position to the second position. A linkage is interconnected to the sensor. The linkage translates motion to the auger.
Core Innovation
This invention provides a device and method for measuring the yield stress of a fluid, particularly suitable for yield stress fluids such as biomass material. The device comprises a container for holding the fluid and an auger with a shaft and a helical flange. The auger moves axially through the fluid between two positions, while a sensor operatively connected to the auger measures the force applied to it during this movement.
The problem addressed relates to the challenges in accurately measuring the rheological properties, specifically the yield stress, of biomass and other non-Newtonian fluids. Existing methods are hampered by issues like wall slip, sample ejection, sensor capacity limitations, and are often slow and expensive. For example, current torque rheometry methods can take about 1.5 hours per measurement and require apparatus costing between $50,000 and $100,000.
The invention aims to provide a simpler, more cost-effective and faster method and device to measure the rheological properties of yield stress fluids. Its design involves an auger that is threaded into the fluid and connected to a load cell sensor via a linkage system driven by a motor. The system translates rotary motion into linear displacement of the auger, and by measuring the maximum force exerted on the sensor when the auger is moved, the yield stress can be calculated using a defined expression involving the force, auger depth and diameter.
Claims Coverage
The patent contains one independent method claim focusing on a systematic procedure for measuring shear yield stress.
Method for measuring shear yield stress using an auger and sensor system
- Rotatably threading an auger into a fluid portion. - Interconnecting the auger to a sensor that generates a force-corresponding signal. - Operatively connecting the sensor to a motor via linkage. - Rotating the motor shaft and converting this rotary motion into linear motion with the linkage to displace the auger linearly without rotation. - Determining the maximum force point on the sensor. - Calculating the shear yield stress based on this maximum force signal.
The claim focuses on a method utilizing an auger displaced linearly by a motor-driven linkage system with force measurement by a sensor to determine the shear yield stress of a fluid.
Stated Advantages
The device and method are simple to operate and inexpensive to manufacture compared to existing expensive apparatuses.
They allow for quick acquisition of rheological measurement results, improving efficiency.
Documented Applications
Measuring the yield stress of biomass material to assist in designing industrial processes and equipment for biomass-to-biofuel conversion.
Measuring rheological properties of other non-Newtonian fluids requiring high stress or special handling.
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