Patent Application
20240035946
This invention relates to the field of instrumentation and electronics engineering. Particularly, this invention relates to systems, methods, and apparatus concerning measurements and sensing of viscosity or one or more rheological properties of fluids.
Rheological properties of fluids relate to one of several flow characteristics of a fluid material. Typically, the term, ‘rheological property’ relates to parameters such as viscosity, thixotropic index, dispense rate, sag resistance, among others.
Firstly, it was observed that prevalent prior art mechanisms are bulky since they use large transducers that include actuators functioning in association with other sensors, reflectors etc.
There is a continuous need to miniaturize devices, without losing accuracy, with an intention of making them portable. Moreover, increase in measurement/sensing precision and accuracy are desired features, especially if it can be achieved with lower device complexity and cost.
Additionally, it was observed that prevalent prior art mechanisms necessitate feedback from the transducers and/or the sensors for maintaining constant amplitude and/or velocity of a vibrating member/element/shaft as means of calibration and/or accurate sensing. In such cases, the actuators and/or any attached vibrating members/elements/shafts are driven at the mechanical (or electro-mechanical) resonant frequencies of vibration of the system.
There is, therefore, a need to decrease complexity of sensing methodologies and mechanisms in both open-loop and closed-loop measurements of rheological properties of fluids (such as viscosity). Such technological advancements that decrease sensing/measurement complexity can, in turn, decrease associated design, manufacturing, assembly, and maintenance complexities, thereby decreasing costs and enabling portability.
Furthermore, it was observed that even with the advent of miniaturized electronics, especially micro and nano electromechanical systems (MEMS/NEMS) such as accelerometers, gyroscopes, pressure sensors, and their combinations in inertial measurement units (IMUs), their application to the field of sensing rheological properties was restricted, in that, the prior art does not disclose a method of construction of an apparatus which senses viscosity of a fluid, accurately using such miniaturized sensing and actuation systems. Prior miniaturized rheological sensing systems have been limited to microfluidic lab-on-chip demonstrations that often compromise performance, ease of use, and portability, and are therefore, largely absent from commercialized applications.
Still further, it was observed that even with the advent of miniaturized electronics, their application to the field of sensing rheological properties were restricted, in that, the prior art does not disclose a method of signal processing for sensing one or more rheological properties (e.g. viscosity) of a fluid, accurately, especially using inputs and outputs of these miniaturized sensors and actuators
It was also observed, in prior art documents, that because an actual sensor (or a part of a sensing mechanism) has to be deployed on a vibrating member, the size/mass/weight of the sensing mechanism places physical (sizing, mechanical) constraints on this vibrating member. Sensing mechanisms described in prior art (bulky combinations of piezoelectric elements and or electric coils and magnetic systems) are also difficult to miniaturize to microscale dimensions. There is, therefore, an advantage to using a miniaturized sensing mechanism (especially a MEMS/NEMS sensor system) because it obviates or significantly minimizes the effect of the sensor system's physical dimensions and mass on the design and performance of the viscosity/rheological property measurement device. Additionally, using a miniaturized sensing system reduces the complexity of the overall system design, such as enabling greater flexibility in the placement of the actuation and sensing systems to maximize one or more overall device performance metrics such as sensitivity, dynamic range, etc.
For example, it was observed, in prior art documents, that the weight of the vibrating member which supports the sensing mechanism was correlated to the weight of the sensing mechanism itself in order to produce a discernible signal that can be used for sensing.
There is, therefore, a need to disconnect this dependence/correlation.
An object of the invention is to provide an apparatus and method which senses viscosity and/or at least a rheological property, of a fluid by making the apparatus light, portable, and accurate.
Another object of the invention is to provide an apparatus and method which senses viscosity and/or at least a rheological property, of a fluid by reducing time taken to measure a rheological property of a fluid.
Still another object of the invention is to provide an apparatus and method which senses viscosity and/or at least a rheological property, of a fluid by reducing complexity in its design/construction.
An additional object of the invention is to provide an apparatus and method which senses viscosity and/or at least a rheological property, of a fluid by eliminating the need for using complex closed-loop feedback mechanisms and associated sensing and drive electronics to maintain a constant vibration displacement and/or velocity amplitude in a fluid (at resonance frequency or any other drive frequency).
According to this invention, there is provided an apparatus for measuring, viscosity or one or more rheological properties of fluids as a function of at least one signal, said apparatus comprises:
In at least an embodiment, said member is selected from a group of members consisting of a rod member, a cylindrical object member, a shim member, an oblong member, an ellipsoidal member, a cuboidal member, and a stiff strip member.
In at least an embodiment, said Inertial Measurement Unit comprises an accelerometer, attached to said member, said accelerometer being configured to measure acceleration, about one or more orthogonal axes.
In at least an embodiment, said Inertial Measurement Unit comprises a gyroscope, attached to said member, said gyroscope being configured to measure angular velocity, and/or angular displacement, and/or orientation (attitude), about one or more orthogonal axes.
In at least an embodiment, said Inertial Measurement Unit comprises at least an element selected from a group of elements consisting of MEMS gyroscopes, NEMS gyroscopes, angular rate sensors, rate integrating gyroscopes, angular rate sensors based on the Coriolis effect, accelerometers, magnetometers, MEMS accelerometers, NEMS accelerometers, MEMS magnetometers, pressure sensors, barometers, and temperature sensors.
In at least an embodiment, said Inertial Measurement Unit being located at a point, on said member, said point selected from a locus of points defined to be linearly increasing from an operative distal end portion on said member, said operative distal end portion being configured to be dipped in fluid, said locus of points being correlative to desired sensitivity, in that, a relatively closer point, from said operative distal end portion, providing relatively higher sensitivity, and a relatively farther point, from said operative distal end portion, providing relatively lesser sensitivity.
In at least an embodiment, said apparatus comprises one or more Inertial Measurement Units on said member, each of said Inertial Measurement Units being spaced apart from each other and being positioned in terms of their distance from an operative distal end portion of said member, said distal end portion being configured to be dipped into a fluid.
In at least an embodiment, said Inertial Measurement Unit abuts said member.
In at least an embodiment, said motor abuts said member.
In at least an embodiment, said motor having an output, with amplitude and/or frequency of said output, being controlled by varying voltage or current applied to said motor.
In at least an embodiment, said member comprises one or more temperature sensors.
In at least an embodiment, said apparatus comprises fins, attached to said member, said fins projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static.
In at least an embodiment, said apparatus comprises fins, attached to said member, said fins projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static, characterized in that, one or more vibrating fins being configured to vibrate with one or more corresponding vibrating frequencies, said one or more corresponding frequencies being same or distinct with respect to each other.
In at least an embodiment, said apparatus comprises fins, said fins projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static, characterized in that, said vibrating fins being attached to said member, said static fins being attached to an outer housing configured to cover a portion of said member, one or more of said static fins being located on one or more sets of locus of points equidistant from one or more of said vibrating fins, thereby defining a first distance of a first static fin from an operative central vibrating fin and a second distance of a second static fin from said operative central vibrating fin, said first distance being equal to said second distance in order to establish an equal shear rate, in said fluid, on either side of said vibrating fin.
In at least an embodiment, said apparatus comprises fins, said fins projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static, characterized in that, said vibrating fins being attached to said member, said static fins being attached to an outer housing configured to cover a portion of said member, one or more of said static fins being located on one or more sets of locus of points equidistant from one or more of said vibrating fins, thereby defining a first distance of a first static fin from an operative central vibrating fin and a second distance of a second static fin from said operative central vibrating fin, said first distance being not equal to said second distance in order to establish two different shear rates, in said fluid, on either side of said vibrating fin.
In at least an embodiment, said apparatus comprises fins, attached to said member, said fins projecting in an operatively downward manner, co-axially, laterally, or radially with respect to said member, said fins being configured to be vibrating or being configured to be static.
In at least an embodiment, said apparatus comprises:
In at least an embodiment, said apparatus comprises fins attached to, said member, said fins comprises one or more temperature sensors.
In at least an embodiment, said apparatus comprises:
In at least an embodiment, said apparatus comprises:
In at least an embodiment, said apparatus comprises:
According to this invention, there is provided a method, for measuring viscosity or one or more rheological properties of fluids as a function of one or more signals, said method comprises:
In at least an embodiment, said one or more signals is selected from a group of signals consisting of:
In at least an embodiment, said step of ‘determining viscosity or one or more rheological properties’ comprises the steps of:
In at least an embodiment, said at least one signal is that of an acceleration signal, a velocity signal, a displacement signal, an angular velocity signal, an angular acceleration signal, an angular displacement signal, and/or a combination of these signals; where the acceleration signal is measured about one or more orthogonal axes of the accelerometer, and where the angular velocity signal and/or the angular acceleration signal and/or the angular displacement signal is measured about one or more orthogonal axes of an angular rate sensor or a gyroscope or a rate-integrating gyroscope.
In at least an embodiment, said step of determining viscosity or one or more rheological properties, comprises at least a step of determining at least a shear rate of said fluid via one or more fins, projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static, characterized in that, said vibrating fins being attached to said member, said static fins being attached to an outer housing configured to cover a portion of said member, one or more vibrating fins being configured to vibrate with one or more corresponding vibrating frequencies, said one or more corresponding frequencies being equal or distinct with respect to each other.
In at least an embodiment, said step of determining viscosity or one or more rheological properties comprises at least a step of determining at least a shear rate of said fluid via one or more fins, projecting in an operatively downward manner, said fins being configured to be vibrating or being configured to be static, characterized in that, said vibrating fins being attached to said member, said static fins being attached to an outer housing configured to cover a portion of said member, one or more of said static fins being located on one or more sets of locus of points equidistant from one or more of said vibrating fins, thereby defining a first distance of a first static fin from an operative central vibrating fin and a second distance of a second static fin from said operative central vibrating fin, said first distance being equal to said second distance in order to establish an equal shear rate, in said fluid, on either side of said vibrating fin.
In at least an embodiment, said step of determining viscosity or one or more rheological properties comprises at least a step of determining at least a shear rate of said fluid via one or more fins, said fins being configured to be vibrating or being configured to be static, characterized in that, said vibrating fins being attached to said member, said static fins being attached to an outer housing configured to cover a portion of said member, said fins being configured to be vibrating or being configured to be static, characterized in that, one or more of said static fins being located on one or more sets of locus of points equidistant from one or more of said vibrating fins, thereby defining a first distance of a first static fin from an operative central vibrating fin and a second distance of a second static fin from said operative central vibrating fin, said first distance being not equal to said second distance in order to establish two different shear rates, in said fluid, on either side of said vibrating fin.
The invention will now be described in relation to the accompanying drawings, in which:
According to this invention, there is provided an apparatus and method for measuring viscosity and/or one or more rheological properties of fluids. The apparatus of this invention is configured to sense/detect viscosity and/or one or more rheological properties as a function of at least one signal (such as an amplitude signal, a frequency signal, and/or the like signal), typically, using an Inertial Measurement Unit (comprising an accelerometer, configured to sense/measure acceleration, about one or more orthogonal axes, and optionally, along with a gyroscope, configured to sense/measure angular velocity/angular displacement/angular orientation and/or attitude, about one or more orthogonal axes). The rheological and/or physical property of a fluid sensed or measured by the apparatus can also include its thixotropic index, dispense rate, sag resistance, viscosity, static viscosity, dynamic viscosity, kinematic viscosity, compressibility, volume elasticity, density, temperature, or a combination thereof.
In at least an embodiment, the apparatus (100) comprises a member (12) with an Inertial Measurement Unit (14) coupled to the member (12). A motor (16) is also coupled to this member (12) in order to make the member (12) a vibrating member, the vibration being imparted, to the member (12), by the motor (16). This member (12) is configured to be dipped into a fluid whose viscosity and/or one or more rheological properties are to be measured/sensed/recorded. It is generally understood that the motor is an electrically driven motor or an electric motor. In one or more embodiments, the apparatus (100) comprises an anchor, a clamp, or a point at which the member is held by hand (15).
In at least an embodiment, the member (12) is selected from a group of members consisting of a rod member, a cylindrical object member, a shim member, an oblong member, an ellipsoidal member, a cuboidal member, and a stiff strip member.
In at least an embodiment, the Inertial Measurement Unit (14, 14a, 14b) comprises an accelerometer, configured to sense/measure acceleration, about one or more orthogonal axes, optionally along with a gyroscope, configured to sense/measure angular velocity/angular displacement/angular orientation and/or attitude, about one or more orthogonal axes. In some embodiments, an accelerometer is attached to the vibrating member. In some embodiments, a gyroscope is attached to the vibrating member. In some embodiments, the IMU comprises one or more of MEMS/NEMS gyroscopes (angular rate sensors and/or a rate integrating gyroscope), accelerometers, magnetometers, pressure sensors, barometers, and temperature sensors, on a single die or on multiple dies integrated with application-specific integrated circuits (ASICs) in a single package and/or housing.
In at least one embodiment the motor (16) is a motor selected from a group of motors consisting of a vibration motor, an eccentric rotating mass vibration motor, a brushless direct current motor, a coin motor, a brushed eccentric rotating mass vibration motor, a brushless direct current eccentric rotating mass vibration motor, and a linear resonant actuator. In an alternative embodiment, the actuator or the motor (16) can be replaced with a piezoelectric element that strains or flexes or vibrates when a voltage or a time-varying voltage is applied to it.
In an alternative embodiment, the IMU/accelerometer/gyroscope/sensor could be placed/positioned at an arbitrary effective distance, r2, from the member anchor point/axis, such that the arc length, S2, travelled by the member in a given duration (or period of time or time interval) at the point on the member is given by S2=r2·θ. In yet another embodiment, the position of the IMU/accelerometer/gyroscope/sensor along the member, indicated by the effective distance, r1, or r2, could be varied to increase or decrease the sensitivity of the measurement apparatus, or vary the measured/obtained signal strength or one or more measured/obtained signal parameters such as the signal amplitude, the signal range, and/or the signal-to-noise ratio (SNR). For example, to increase the amplitude of the signal obtained from the IMU accelerometer (14) or a standalone accelerometer (or acceleration sensor), for a given member vibration frequency or a given motor actuation voltage (or current), the IMU accelerometer or the standalone accelerometer (or acceleration sensor) that is placed/positioned, on the member (12), further away from the member anchor point (15) (or member pivot axis or member clamp) will output a larger signal amplitude than one that is placed closer to the anchor point, as indicated by the effective distances r2 and r1, respectively, in
In yet another embodiment (as shown in
In some embodiments, the Inertial Measurement Unit (14) comprises an accelerometer to measure variation(s) in arc length w.r.t time, s(t), with viscosity, η, variations of different fluids. Alternatively, the change in the amplitude of the acceleration (a) waveform output, due to immersion of the vibrating member (12) in a fluid of differing viscosity, is proportional to the change in the viscosity between the two media (for example, fluid and air), and can be used to calculate the unknown viscosity of the fluid, given the known viscosity of air (or another fluid with a known/calibrated viscosity or associated rheological parameter) at the known/measured temperature and pressure, that is, Δa∝Δη=ηfluid−ηair.
In some embodiments, the Inertial Measurement Unit (14) comprises a gyroscope/angular rate sensor to measure θ(t) variation with viscosity (η) (or an associated rheological parameter) variations of different fluids. Because the arc travelled (s in
measured by the gyroscopes at both positions should be equal or very close in value to each other to further corroborate accelerometer-aided measurements of viscosity (or associated rheological parameters). This viscosity value can then replace or supplement the kinematic viscosity (ratio of the viscosity to the density of the fluid) value that, for example, Zahn/Ford cup users currently obtain.
Once the member (12) vibrates, the inertial measurement unit (14) transduces motion of the vibrating member into an electrical signal by using its sensors to detect at least a signal correlative to (change in) amplitude of vibration and to detect at least a signal correlative to (change in) frequency of vibration. In a fluid, once a vibrating member is dipped, its vibrations will dampen—thus causing change in the frequency of vibration and the amplitude of vibration; this dampening (or change) signals are sensed and used to determine viscosity (or associated rheological parameters) of the fluid in which the vibrating member is placed; this viscosity value(s) (or associated rheological parameters) being a function of one of the signals.
In at least an embodiment, a first signal is correlative to amplitude of vibration, of said vibrating member, said vibration being measured about one or more orthogonal axes of a sensor of said Inertial Measurement Unit.
In at least an embodiment, a second signal is correlative to frequency of vibration, of said vibrating member, said vibration being measured about one or more orthogonal axes of a sensor of said Inertial Measurement Unit.
In at least an embodiment, a third signal is correlative to change in amplitude of vibration, of said vibrating member, said vibration being measured about one or more orthogonal axes of a sensor of said Inertial Measurement Unit.
In at least an embodiment, a fourth signal is correlative to change in frequency of vibration, of said vibrating member, said vibration being measured about one or more orthogonal axes of a sensor of said Inertial Measurement Unit.
In at least an embodiment, a fifth signal is correlative to change in amplitude of acceleration, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more accelerometers of said Inertial Measurement Unit.
In at least an embodiment, a sixth signal is correlative to change in frequency of acceleration, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more accelerometers of said Inertial Measurement Unit.
In at least an embodiment, a seventh signal is correlative to change in amplitude of angular velocity, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more gyroscopes of said Inertial Measurement Unit.
In at least an embodiment, an eighth signal is correlative to change in frequency of angular velocity, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more gyroscopes of said Inertial Measurement Unit.
In at least an embodiment, a ninth signal is correlative to phase of a signal driving said motor.
In at least an embodiment, a tenth signal is correlative to voltage signal driving said motor.
In at least an embodiment, an eleventh signal is correlative to difference in phase between a signal driving said motor and said first signal.
In at least an embodiment, a twelfth signal is correlative to difference in phase between a signal driving said motor and said second signal.
In at least an embodiment, a thirteenth signal is correlative to difference in phase between a signal driving said motor and said third signal.
In at least an embodiment, a fourteenth signal is correlative to difference in phase between a signal driving said motor and said fourth signal.
In at least an embodiment, a fifteenth signal is correlative to temperature of said fluid.
In at least an embodiment, a sixteenth signal is correlative to pressure of said fluid.
In at least an embodiment, a seventeenth signal is correlative to current flowing through said motor, as measured using a current sensor or a current sensing integrated circuit or an electronic circuit.
In at least an embodiment, an eighteenth signal is correlative to ambient temperature.
In at least an embodiment, a nineteenth signal is correlative to change in frequency of one or more peaks present in a frequency-domain spectrum of a time-domain angular velocity signal, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more gyroscopes of said Inertial Measurement Unit.
In at least an embodiment, a twentieth signal correlative to change in frequency of one or more peaks present in a frequency-domain spectrum of a time-domain acceleration signal, of said vibrating member, said vibration being measured about one or more orthogonal axes of one or more accelerometers of said Inertial Measurement Unit.
In a preferred embodiment, the Inertial Measurement Unit (IMU) is located at a position further away from the anchor or the clamp of the vibrating member in order to improve or optimize the sensitivity of the device. Alternatively, this corresponds to locating the Inertial Measurement Unit closer to the unclamped or the free end of the vibrating element. In some embodiments, the Inertial Measurement Unit (14) is co-axial to the member (12). In a general sense, the sensitivity or the strength of the detected signal output from the apparatus increases the further the IMU is located away from the vibrating element clamp or anchor.
In an embodiment, the motor (16) is co-axial to the member (12). In yet another embodiment, the motor abuts the vibrating element or the member.
In an embodiment, the position of the motor relative to the length of the vibrating element or member is optimized such as to maximize the acceleration and/or the angular velocity of the vibrating element (or member) at its free (vibrating) end and/or at the position of one or more of the IMUs.
In a preferred embodiment, the motor (16) is a vibration motor or an eccentric rotating mass vibration motor.
In yet another embodiment, the motor (16) has an output rotating shaft that is attached to the vibrating element or member, or is co-axial to the vibrating element or member.
In yet another embodiment, the motor (16) is a linear resonant actuator (LRA).
In yet another embodiment, the actuation mechanism comprises more than one motor and each motor can be of the same type or a combination of one or more types of motors described above.
It is to be understood that the position of the various sensors can be static or dynamic and be varied in real time or fixed prior to manufacturing in order to yield optimal signal parameters such as sensor output sensitivity and/or dynamic range.
It is to be understood that the position of one or more motors/actuators can be static or dynamic and be varied in real time or fixed prior to manufacturing in order to yield optimal signal parameters such as sensor output sensitivity and or dynamic range.
It is to be understood that the apparatus, of this invention, can be handheld or clamped with the position of the clamp anchor point being variable.
Referring to
For a rigid vibrating member (12), we have
s=r×θ.
Differentiating the equation above w.r.t time, we get
Differentiating the equation above w.r.t time again, we get
we have Δa∝Δη=ηfluid−ηair and, therefore, via integration, Δ⋅∝Δη and Δθ∝Δη, and this signal due to fluidic viscous drag should show up in the IMU gyro/ARS outputs as well. [Note that the ∝ symbol is used here to represent “is proportional to”. Note that the Δ symbol is used to represent the change in a parameter or a quantity or a variable, with respect to another variable or set of variables, such as time, space, medium, temperature, density etc.]
In at least an embodiment, a method to detect/sense viscosity and/or one or more rheological and/or physical properties of a fluid such as its thixotropic index, dispense rate, sag resistance, viscosity, static viscosity, dynamic viscosity, kinematic viscosity, compressibility, volume elasticity, density, temperature, or a combination thereof) of a fluid is disclosed, the method comprising:
In at least an embodiment, said amplitude is that of an acceleration signal, a velocity signal, a displacement signal, an angular velocity signal, an angular acceleration, and/or a combination of these signals; where the acceleration signal is an output of one or more orthogonal axes of the accelerometer, and where the angular velocity signal and/or the angular acceleration signal is an output of the one or more orthogonal axes of the angular rate sensor or the gyroscope. The amplitude can refer to that of sensed or measured displacement, velocity, and/or acceleration.
In at least an embodiment, said frequency is that of an acceleration signal, a velocity signal, a displacement signal, an angular velocity signal, an angular displacement signal, and/or a combination of these signals; where the acceleration signal is an output of one or more orthogonal axes of the accelerometer, and where the angular velocity signal and/or the angular displacement signal is an output of the one or more orthogonal axes of the angular rate sensor or the gyroscope. The amplitude can refer to that of sensed or measured displacement, velocity, and/or acceleration. The frequency can refer to that of the sensed or measured angular frequency, angular velocity and/or angular displacement.
An additional or an alternative measurement mode could include a calibration mode or a calibration routine or a calibration sub-routine where a user calibrates the apparatus, of this invention, before measuring viscosity and/or one or more rheological properties of a fluid or of a test fluid by performing the pre-defined measurement routine/s by:
According to a non-limiting exemplary embodiment, the apparatus, of this invention, was configured with an accelerometer having a single-axis output and the member, having this accelerometer, is dipped and removed from a volume of a viscous medium or fluid (Newtonian or non-Newtonian) such as curry ketchup or honey.
In the plot, shown in
The acceleration measurement, discussed above, for curry ketchup is then repeated for a heuristically more viscous fluid: honey. The acceleration measurement exhibits the same trend as that noticed for curry ketchup, with the acceleration amplitude decreasing whenever the oscillating member is dipped in honey and then increasing back to its prior value whenever the member is removed from honey and into air.
The oscillating member acceleration waveforms shown in the plots, of Figure of the accompanying drawings, for curry ketchup and honey are now plotted on the same axes, to compare and highlight the greater change (decrease) in acceleration amplitude for member oscillations in more viscous fluids. Since honey is visibly/heuristically more viscous (“thicker”) than curry ketchup, it was expected that the acceleration amplitude decreases more when the oscillating member is dipped into it as compared to in curry ketchup. The plot, of
Therefore, the plot comparing the acceleration data for honey and curry ketchup (w.r.t. air as baseline), as seen in
In an embodiment, a temperature sensor is configured on the member (12) (or at its distal end portion) such that the temperature sensor senses fluid temperature when the member is dipped into a fluid whose viscosity (or one or more rheological property) is to be sensed/detected. Here, another signal is measured which is sensed temperature data. This enables the user to obtain viscosity (or associated rheological parameter) values simultaneously with temperature values. This signal is used, further, to calculate viscosity (or associated rheological parameter) and/or adjust the measured value of the fluid's viscosity and/or other rheological and/or physical parameters of the fluid.
In an embodiment, surface functionalization or nano-structuring or texturing or coating of the vibrating member (12) can be done such that paint/glue/blood/other non-Newtonian fluid/or Newtonian fluid/or fluid does not stick to the member and the rod is easy to clean or reuse after a measurement.
In some embodiments, a pressure sensor is configured on the member (12) (or at its distal end portion or at a handle or at a motor housing) such that the sensor senses fluid pressure when the member is dipped into a fluid whose viscosity (or associated rheological parameter) is to be sensed/detected.
Here, another signal is measured which is sensed pressure data. This enables the user to obtain viscosity values simultaneously with pressure values. This other signal is used, further, to calculate viscosity (or associated rheological parameter) and/or adjust the measured value of the fluid's viscosity and/or other rheological and/or physical parameters of the fluid.
The shear rate, Rshear, for a fluid flowing between two parallel plates, one moving at a constant speed or velocity, v, and the other one stationary, is given by
In an exemplary embodiment of the viscosity measurement apparatus or the rheometry apparatus, in order to calculate/compute the shear rate for a viscous fluid that the apparatus member is dipped in, the velocity of the moving plate or the moving fin that is attached to the sinusoidally vibrating or oscillating member (or rod) of the apparatus can be measured or calculated or computed using the outputs of the one or more accelerometers and/or the one or more gyroscopes disposed on the apparatus member and/or disposed on the fins/plates that are attached to the apparatus member. In this embodiment, the apparatus can therefore be used to characterize the viscosity or the static viscosity (or other rheological properties) of fluids at different shear rates, or as a function of a range of shear rate values. Such a shear-rate-dependent characterization of fluid viscosity and/or other rheological properties is important, and often critical, for a wide variety of fluids, including Newtonian fluids, and especially, for non-Newtonian fluids. The viscosity of non-Newtonian fluids is dependent on the shear rate of the fluid. Therefore, the aforementioned embodiment of the apparatus can be used to establish a known shear rate of the viscous fluid into which it is dipped, and measure the viscosity of that fluid at that shear rate. The fluid shear rate can also be varied by changing the frequency of vibration of the apparatus member (by varying the motor vibration frequency, by changing the applied motor voltage and/or current), thereby changing the velocity or the speed of the fin or the plate that is in motion, or in sinusoidal harmonic motion, in its own plane, relative to the parallel fin or plate (or with respect to the parallel stationary plate). The fluid viscosity measurement can then be repeated at another fluid shear rate value. This process can be repeated to characterize the viscosity, or the static viscosity, or a rheological property, of a fluid, as function of the fluid shear rate (and other parameters such as temperature), over a range of fluid shear rates.
The shear-rate rheometry apparatus, or attachment, typically, comprises one or two static fins or plates (25) on either side of the vibrating fins (20) such that the static fins (25), being laterally located about a medial vibrating fin (20), have their largest face along a plane which is either parallel to, or within 45 degrees of angular displacement, with respect to a medially located vibrating fin (20). The distances, X and Y, could be the same to establish the same shear rate in the viscous fluid on either side of the vibrating fins (20) or could be designed and fabricated/3D-printed/manufactured such that they are of two distinct values to establish two different shear rates in the viscous fluid for a given vibrating fin/member frequency.
In an embodiment of this invention, the apparatus comprises fins collinear to, and attached to, the vibrating member (12). Typically, these fins (20) project operatively downwards from the vibrating member (12); these fins (20) may be vibrating fins (20) or static (non-vibrating) fins (25). These fins (20) could come as either a removable or a permanent attachment. These fins (either in their vibrating phase or in their static phase) are used, along with the vibrating member (12), in order to determine shear rate of the fluid, whose rheological properties are to be measured, using the apparatus, of this invention. Typically, these fins/plates, as they are planar surfaces in nature, increase surface area of the part of the apparatus that is dipped into fluid; which, in turn, increases drag force/s and or viscous force/s exerted by the fluid and experienced by the vibrating part of the apparatus; which, in turn, decreases total force/s acting on the vibrating part of the apparatus. These forces can be sensed, with the apparatus of this invention, to determine viscosity (or one or more rheological parameters) of the fluid and other rheological properties of the fluid.
In some embodiment, the fins project in an operatively downward manner, co-axially, laterally, or radially with respect to said member.
The equation that expresses the impedance encountered by the vibrating member in the viscous fluid is given by:
Z
mech
=A√{square root over (πηρf)}
The use of such fins/plates increases at least one of the following: sensitivity, measurement signal strength, signal fidelity, signal accuracy, signal precision.
In some embodiments, an outer housing (10) ensconces or attaches to a portion of the vibrating member (12) such that a distal end portion/stub of the vibrating member (12), which is to be dipped in fluid, whose rheological parameters are to be measured, is protruding.
In preferred embodiments, vibrating fins (20) are collinear and coaxial to the vibrating member (12) and extend, operatively downwards, beyond the distal end portion of the operative member.
In preferred embodiments, static fins (25) are spaced apart from the vibrating fins (20). Preferably, static fins (25) are two, diametrically opposite, fins having planar surfaces parallel to/facing the central vibrating fin (20).
In some embodiments, the static fins (25) are located on a locus of points equidistant from the vibrating fins (20); these leave value X (distance of a first static fin from the central vibrating fin) to be same as value Y (distance of a static fin from the central vibrating fin). The distances X and Y could be the same to establish the same shear rate on either side of the vibrating fins.
In some embodiments, the static fins (25) are located on a locus of points non-equidistant from the vibrating fins (20); these leave value X (distance of a first static fin from the central vibrating fin) to be different than value Y (distance of a static fin from the central vibrating fin). The distances X and Y could be the different to establish the different shear rates (two distinct values to establish two different shear rates) on either side of the vibrating fins. This allows for faster measurement, better correlation, and more accurate data.
In one embodiment, of the fluid viscosity (or one or more rheological parameters) measurement/characterization apparatus, of this invention, the portion of the apparatus or the member (12) that is either partially or fully dipped into the fluid (whose viscosity and/or rheological property is to be measured) can have an enlarged face (20), as shown, at least, in
Since the drag force or the frictional force exerted on the vibrating/moving/oscillating part of the apparatus due to the viscosity (or associated rheological parameter) of the fluid/liquid/medium is proportional to the surface area of the moving element of the apparatus, a larger surface area, therefore, results in a larger drag force (or frictional force or viscous force) that opposes or impedes the motion of the vibrating/moving/oscillating part/element of the apparatus, which in turn, decreases the total force (or the net sum of forces) acting on the actuated, vibrating element (12) of the apparatus (the member). This decrease in the total force (or the net sum of forces) acting on the vibrating/moving/oscillating part/element of the apparatus results in a decrease in the amplitude of the acceleration and the amplitude of the velocity of the vibrating/moving element of the apparatus when a portion of that vibrating element of the apparatus is dipped into a more viscous medium such as a liquid/fluid. Similar decreases are also observed for parameters such as the amplitude of the angular velocity of the vibrating member and the amplitude of the angular displacement of the vibrating member. This decrease in the total force (or the net sum of forces) acting on the vibrating/moving/oscillating element of the apparatus, and the associated decrease in the amplitude of the acceleration, or in the amplitude of the velocity, or in the amplitude of the angular velocity, or in the amplitude of the angular displacement, of the vibrating/moving element of the apparatus, when a portion of that vibrating element of the apparatus is dipped into a more viscous medium such as a liquid/fluid, is proportional to the viscosity (or associated rheological parameter) of that liquid/fluid/medium, and/or is proportional to one or more rheological properties or parameters of that liquid/fluid medium such as the density of the fluid, or the square-root of the product of the viscosity (or associated rheological parameter) and the density of the fluid, or the square-root of the product of the viscosity (or associated rheological parameter) the density of the fluid and the frequency of the apparatus element vibration/oscillation. In an exemplary embodiment, of the fluid viscosity measurement apparatus or the fluid rheological property characterization apparatus, of this invention, the aforementioned decrease in total force (or net sum of forces) acting on the vibrating/moving/oscillating element of the apparatus, or decrease in amplitude of the acceleration, or decrease in amplitude of velocity, or decrease in amplitude of angular velocity, or decrease in amplitude of angular displacement, of the vibrating/moving element of the apparatus, when a portion of that vibrating element, of the apparatus of this invention, is dipped into a more viscous medium such as a liquid/fluid, can be sensed and/or measured, and be processed, and be used to calculate/measure the viscosity, or one or more rheological properties, of the fluid/liquid medium, such as the product of the viscosity (or associated rheological parameter) and the density of the fluid/liquid, or its static viscosity. Alternatively, the calculated/measured viscosity, or one or more rheological properties, of the fluid/liquid medium, such as the product of the viscosity (or associated rheological parameter) and the density of the fluid/liquid, or its static viscosity can be measured or specified as function of the shear rate of the fluid/liquid or as a function of the vibration/oscillation/actuation frequency of the moving element of the apparatus.
Since the aforementioned decrease (or change) in the total force (or the net sum of forces) acting on the vibrating/moving/oscillating element of the apparatus—or the decrease (or change) in amplitude of acceleration, or decrease (or change) in amplitude of velocity, or decrease (or change) in amplitude of angular velocity, or decrease (or change) in amplitude of angular displacement of vibrating/moving element of the apparatus—when a portion of that vibrating element is dipped into a more viscous medium such as a liquid/fluid, is proportional to the surface area of the apparatus that interacts with the drag force or the frictional force exerted on the apparatus due to the viscosity (or associated rheological parameter) of the said fluid/liquid medium, the presence of structures with enlarged surface area/s—such as fins or plates or structures (such as hollow shell/s, or solid sphere-like object/s) that increase the surface area of the part of the moving element of the apparatus that is dipped into the fluid/liquid—can be employed to increase the measurement sensitivity or the measurement signal strength or the measurement signal fidelity or the measurement signal accuracy or the measurement signal precision of the apparatus. Some exemplary embodiments of such structures with enlarged face/s are shown, at least, in
In one exemplary embodiment of the measurement apparatus, the fin-like, or plate-like, or shell-like, or hollow spherical shell-like, structures of enlarged face/s can be formed as part of a single (monolithic) element of the measurement apparatus that can be actuated to move/vibrate/oscillate (such as a member that can be attached to a motor), as shown in
In another embodiment, either plate-like spokes, as shown in
In order to decrease or minimize the amount of energy or power that is spent by the power source of the apparatus to actuate or move or vibrate or oscillate the movable element of the apparatus—a portion of which is also dipped into the viscous fluid/liquid—it is prudent to design this movable element and the accompanying structures of enlarged faces (such as the fin-like, or plate-like, or shell-like, or hollow spherical shell-like structures mentioned above) to have a relatively high total (both the member and the fins combined) surface-area-to-mass ratio and/or a relatively high total surface-area-to-volume ratio. Designing with the aforementioned constraint will enable higher nominal acceleration and velocity of the movable element of the apparatus to be achieved, more efficiently, for a given set of actuation parameters such as motor voltage, or motor current, or vibration motor frequency, or motor input power. Relatively high total (both the member and the fins combined) surface-area-to-mass ratio and/or a relatively high total surface-area-to-volume ratio can be achieved enlarging the face of the part/region of the movable element of the apparatus that is to be dipped into the fluid, while keeping the remainder of movable element as light (mass or weight wise) as possible. An exemplary design of the movable element of the apparatus which achieves a relatively high or a higher total surface-area-to-mass ratio (and a higher signal-to-noise ratio or a higher measurement sensitivity) for portable operation, employs an elongate structure, such as a hollow (or a solid) cylindrical member, that is attached to one or more planar fin-like or plate-like structures at its non-clamped or non-anchored end. Some additional exemplary embodiments, of this design, are shown in
An exemplary signal can be the amplitude and/or the frequency of the output/s of the IMU sensor/s or the acceleration sensor/s (or the accelerometer/s) or the angular rate sensor/s (or the gyroscope/s) or the motor current or the current sensor/s. Another exemplary signal can be the difference, or the magnitude of the difference, in the amplitude, and/or the frequency, of the output/s of the IMU sensor/s or the acceleration sensor/s (or the accelerometer/s) or the angular rate sensor/s (or the gyroscope/s) or the motor current or the current sensor/s, between two periods of time, one when the apparatus or the member is held in air (and the motor is in the actuated state resulting in the member being in a vibrating state), and the other when the apparatus or the member is dipped and held in a fluid/liquid (and the motor is in the actuated state resulting in the member being vibrated or being a vibrating state).
Yet another signal can be the difference in the amplitude of one or more peaks in the frequency spectrum of the aforementioned signals including the output/s of the IMU sensor/s or the acceleration sensor/s (or the accelerometer/s) or the angular rate sensor/s (or the gyroscope/s) or the motor current or the current sensor/s. The aforementioned frequency-domain spectrum of the signal can be obtained by using a transform such as the Fourier transform (or the Fast Fourier Transform) between the time and frequency domains of the signal/s. Yet another signal can be the signal that correlates or is proportional to the correlation between the two or more signals mentioned/described above, including (but not limited to) signals corresponding the output of the multiple axes (for example X, Y, Z) of the IMU sensor/s or the acceleration sensor/s (or the accelerometer/s) or the angular rate sensor/s (or the gyroscope/s).
In some embodiments, the vibrating fins (20) comprise integrated temperature sensors.
In some embodiments, static fins (25) comprise integrated temperature sensors.
In at least an embodiment, a first collar (22), which, preferably, ensconces the vibrating member (12), allows for attaching of the vibrating fins (20) to the vibrating member (12).
In at least an embodiment, a second collar (24), which, preferably, ensconces the outer housing (10) which is configured to cover a portion of said member, allows for locating the static fins (25) around the vibrating fins (20). The manner of attachment of the second collar (24) to the outer housing (10) could be any of a snap-fit attachment, a screw-fit attachment, or a magnetic-lock fit attachment.
It is to be understood that, in the alternative embodiment, of
Signal processing techniques such as bandpass filtering, low pass filtering, high pass filtering, or combinations thereof, could be employed to process the collected data to filter out noise from various sources such as from the handheld operation of the apparatus. In an exemplary embodiment, the aforementioned signal processing techniques could be applied to one or more measured signals such as the acceleration and/or the angular velocity and/or the velocity of the vibrating member and/or of the vibrating fins/plates (20) (that are attached to the mechanical actuation motor via the member), relative to the static fins/plates (25) that are attached to the device outer housing (10). This could, in turn, enable a more precise, or a more accurate, determination of fluid viscosity and/or fluid shear rate.
In some embodiments, these parallel fins/plates are configured to vibrate (in phase) with a same velocity (rigid body motion), when actuated, would increase sensitivity or measurement signal amplitude (and signal-to-noise ratio); because of which a dynamic range of viscosities can be measured with the apparatus of this invention. This is because the multiple parallel fins increase the face that is in contact with the fluid and that, in turn, increases drag force/s (or viscous force/s or frictional force/s that oppose the fin/plate motion) experienced by the fins when they move/vibrate in a viscous fluid/medium, thereby increasing sensitivity of the viscosity (or one or more rheological property) measurement apparatus. The fin/plate attachment designs shown in
In addition to the multiple planar surfaces that comprise the fins/plates that, the viscosity (or one or more rheological property) measurement apparatus, of this invention, could also comprise additional surfaces that are orthogonal to one another as also shown in the exemplary embodiments in
The aforementioned member (12) can be made out of, or be made from, or be comprised of, but not limited to, one or more material/s such as various plastic/s, composites, polymers, carbon fiber, carbon fiber-reinforced polymers, thermosetting polymers such as epoxy, polyester resin, vinyl ester resin, thermoplastic/s, fiberglass, glass, silicon, silicon dioxide, metal/s, metals such as aluminum, copper, nickel, gold, alloys, stainless steel, steel, brass, bronze, wood, resins, acetate, polytetrafluoroethylene (PTFE or Teflon), Polyvinylidene fluoride or polyvinylidene difluoride (PVDF), 3D-printed resins, 3D-printing inks or filaments, polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA or acrylic or acrylic glass or Plexiglas or Perspex), polycarbonates.
The aforementioned fins/plates (20, 25) can be made out of, or be made from, or be comprised of, but not limited to, one or more material/s such as various plastic/s, composites, polymers, carbon fiber, carbon fiber-reinforced polymers, thermosetting polymers such as epoxy, polyester resin, vinyl ester resin, thermoplastic/s, fiberglass, glass, silicon, silicon dioxide, metal/s, metals such as aluminum, copper, nickel, gold, alloys, stainless steel, steel, brass, bronze, wood, resins, acetate, polytetrafluoroethylene (PTFE or Teflon), Polyvinylidene fluoride or polyvinylidene difluoride (PVDF), 3D-printed resins, 3D-printing inks or filaments, polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA or acrylic or acrylic glass or Plexiglas or Perspex), polycarbonates.
The aforementioned fins/plates and/or the apparatus member can also be textured, or micro-textured, or nano-textured, or coated with one or more surfactant/s, or thin-film coatings or coatings of hydrophilic nature or of hydrophobic nature, self-assembled molecular layers (SAMs), anti-corrosion coatings, anti-stiction coatings, anti-stick coatings, non-stick coatings, durable slippery coatings, or a combination thereof.
According to a non-limiting exemplary embodiment as depicted in
According to one non-limiting exemplary version of the apparatus, data related to viscosity of honey and ketchup was collected. This data is depicted in
In at least an embodiment, the apparatus comprises a temperature sensor integrated with or coupled to the member or to one or more fins/plates attached to the member. This temperature sensor can be a MEMS temperature sensor, a diode, a thermistor, a thermal sensor, an analog temperature sensor, or digital temperature sensor, an electronic temperature sensor, or a combination thereof. There can be one or more temperature sensors in a single apparatus as claimed in claim 1, integrated or coupled to the apparatus at different positions such as on the member, within the member, on the fin/plate, within the fin/plate, within the housing of the apparatus, or part of the member or the fin that is dipped into the fluid, or part of the member or the housing or the apparatus that is not dipped into the fluid.
The one or more Inertial Measurement Units, accelerometers, gyroscopes, sensors, temperature sensor/s of the apparatus could also communicate with, or be integrated with, or be capable of storing and/or sending their measured data or measurements to one or more circuits or integrated circuits or digital signal processing circuits or microprocessors or microcontrollers or programs or algorithms running on these microprocessor or microcontrollers or on a peripheral device such as a computer, a laptop, an electronic smart watch, a phone, a smart phone, a smart speaker, a cellular phone or device, a smart hearing device such as electronic earbud/s or headphone/s or hearing aid/s, or the cloud.
In an embodiment, the apparatus comprises optional integration of motorized mechanical stirring mechanism or an optional agitating base, attached to the member (12). Such a stirring or agitating mechanism enables the addition of either a predefined stress or shear or a combination thereof to the fluid under characterization. This also allows for the measurement of viscosity and/or other rheological and/or physical parameters of the fluid at a known shear rate or as required for rheological measurements of fluids such as but not limited to blood, plasma, thickeners in food, sealants, adhesives, creams, gels, and other additives or rheological modifiers.
Additionally, such a stirring or agitating mechanism enables real time measurement of viscosity and/or other rheological and/or physical parameters of the fluid as the fluid is being diluted or modified through the use of rheological modifiers.
In some embodiments, the apparatus comprises a display to enable readout of fluid viscosity and/or other rheological and/or physical parameters of the fluid.
In some embodiments, the device and its constituent actuators, motors, sensors, inertial measurement unit/s (IMUs) are powered electrically via a power source such as one or more batteries, button cells, electric cells and/or photovoltaic cells. These power sources are disposed on the device. One or more of these power sources can be replaceable and/or rechargeable.
Additionally, and optionally, the device and its constituent actuators, motors, sensors, inertial measurement unit/s (IMUs) are powered electrically via a wired connection to a portable power source such as a computer, or a laptop, or a tablet computer, or a smart phone (which can include the batteries powering such peripheral devices), and/or via wired connection to a wall outlet or any other non-portable power source.
Alternative embodiments of this device concept also enable the wireless and/or wired transmission of relevant measurement information to a remote device such as a cellphone, smart phone, computer, tablet computer, smart watch, smart hearing device or “hearable”, earphones or earbuds, headphones, hearing aid, or a smart wearable electronic device, a smart speaker, an electronic database stored on a remote device such as a computer or server or “cloud” and/or an digital/electronic notebook or laboratory notebook.
Alternative embodiments of this device concept utilize algorithms aided or informed or based on/by machine learning and/or deep learning and/or artificial intelligence to fuse, integrate, assimilate, augment, the outputs/signals/data of the sensors and actuators that constitute the device described in this invention.
One or more of the sensor outputs can be used to compute, calculate or measure, one or more of the following properties of fluids such as density, viscosity, static viscosity, dynamic viscosity, kinematic viscosity, compressibility and or volume elasticity, thixotropic index, dispense rate, and sag resistance.
The TECHNICAL ADVANCEMENT of this invention lies in measuring/sensing/detecting/recording viscosity and/or one or more rheological properties of a fluid using a vibrating member along with coupled gyroscope measurements and/or accelerometer measurements. While prior art uses traditional motor feedback and control methods to maintain a constant amplitude of member's motion and senses the motor drive current and correlates that current to the fluid's viscosity and/or rheological property/rheological parameter that is being measured, the invention described herein does away with these limitations by using a vibrating member or element along with a coupled gyroscope (angular rate sensor) and/or an accelerometer. The use of miniaturized MEMS accelerometers and gyroscopes, in turn, reduces complexity of drive and sense electronics as compared to those in the prior art; thereby, enabling miniaturization and portability of these apparatus (viscometers) while significantly driving down manufacturing, assembly and maintenance complexity and cost.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements/members/signals, these elements/members/signals should not be limited to any order by these terms. These terms are used only to distinguish one element/member/signal from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element/member/signal could be termed a second element/member/signal, and, similarly, a second element/member/signal could be termed a first element/member/signal, without departing from the scope of example embodiments. As used herein, the term “and/or” includes all combinations of one or more of the associated listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combinations.
While this detailed description has disclosed certain specific embodiments for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10202103946T | Apr 2021 | SG | national |
This application claims priority under 35 U.S.C. § 120 to, and is a continuation of, co-pending International Application PCT/SG2022/050225, filed Apr. 17, 2022 and designating the US, which claims priority to SG Application 10202103946T, filed Apr. 16, 2021, such SG Application also being claimed priority to under 35 U.S.C. § 119. These SG and International applications are incorporated by reference herein in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/SG2022/050225 | Apr 2022 | US |
| Child | 18487208 | US |
