Mixer waveform analysis for monitoring and controlling concrete

• US 8,960,990 B2
• Filed: 03/23/2010
• Issued: 02/24/2015
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: Verifi, LLC (Compagnie De Saint-Gobain)
• Original Assignee: Verifi, LLC (Compagnie De Saint-Gobain)
• Inventors: Koehler, Eric, Verdino, Steve, Culley, Robert
• Primary Examiner(s): Griffin, Walter D
• Assistant Examiner(s): RASHID, FAZLE A
• Application Number:
  US13/260,391
• Publication Number:
  US 20120020180A1
• Time in Patent Office: 1,799 Days
• Field of Search: 366/44, 366/60, 366/61, 700/265
• US Class Current: 366/61
• CPC Class Codes: B28C 7/026 by measuring data of the driving system, e.g. rotational speed, torque, consumed power
• CPC Class Codes: G01N 33/383 Concrete, cement
• CPC Class Codes: G05D 21/02 characterised by the use of electric means

Abstract

Method and system for motoring and obtaining information about quantity and characteristics of cementitious material In a rotating mixing drum. The present invention involves analysis of a sequence of values corresponding to a waveform reflecting the hydraulic pressure required to turn a concrete mixing drum at successive instances during rotation. Preferred embodiments involve the conversion of this time-domain data into the frequency-domain. Behavior of multiple harmonics can be examined in real time and further information obtained regarding physical properties of the concrete. Rheology or other properties can be adjusted by introducing a liquid into the concrete, based on a comparison between time-domain and/or frequency-domain values derived from a sample concrete in the drum and previously stored time-domain and/or frequency-domain values, which are preferably correlated with physical characteristics of concrete, such as slump, slump flow, load weight, and other factors.

Claims

1. A mixing system comprising:

a mixing drum having an inner drum wall and at least two mixing blades mounted on the inner drum wall for mixing a provided concrete contained within the mixing drum;

a drive means for rotating the mixing drum containing the provided concrete at constant speed S^C1 in the range of 1-25 revolutions per minute;

a sensor for providing a sequence of values over time corresponding to the energy required by the drive means to rotate the mixing drum, the provided sequence of values enabling a computer processing unit to detect shape transitioning in the waveform data corresponding to concrete flowing over the at least two blades mounted in the drum within one rotational cycle of the mixing drum;

a data memory storage location having waveform data derived from a previously stored sequence of values over time corresponding to the energy required to rotate a mixing drum containing a previous concrete as monitored by a sensor during rotation of the mixing drum at a frequency of at least 10 times constant speed S^C1 of mixing drum rotation, the stored waveform data enabling a computer processing unit to detect shape transitioning in the waveform data corresponding to concrete flowing over the at least two blades mounted in the drum within one rotational cycle of the mixing drum; and

a computer processing unit which performs the following functions;

monitors at a frequency of at least 10 times constant speed S^C1 of mixing drum rotation the sequence of values provided by the energy sensor to obtain waveform data containing shape transitioning in waveform data corresponding to concrete flowing over at least two blades mounted in the drum within one rotational cycle of the mixing drum rotation, and corresponding to the amount of energy required by the drive means to rotate the mixing drum containing the provided concrete;

analyzes the provided sequence of values in the time domain, the frequency domain, or in both the time domain and frequency domain, for variations in waveform data within one rotational cycle of the mixing drum;

compares waveform data variations within the provided sequence of values to waveform data variations within the previously stored sequence of values; and

adjusts the slump, slump flow, or other property of the provided concrete by introducing a liquid into the mixing drum containing the provided concrete based on the comparison of compared waveform data variations in provided and previously stored sequences of values;

the waveform data variations being correlated with at least two properties or conditions of the concrete or mixing drum selected from (a) load weight, (b) load volume, (c) concrete density, (d) concrete air content, (e) concrete slump, (f) concrete slump flow, (g) concrete flow table value, (h) concrete rheology selected from yield stress, viscosity, and thixotropy, (i) segregation of concrete components, (j) concrete setting, (k) inclination of the mixing drum, (I) size and configuration of the internal drum structure; and

(m) build-up of concrete in the drum.

2. The mixing system of claim 1 wherein the properties of the concrete are concrete air content and concrete slump.

3. The mixing system of claim 1 wherein the computer processing unit further compares the waveform data variations which were derived from provided and previously stored sequences of values and correlated with concrete slump flow.

4. The mixing system of claim 1 wherein a sequence of values and waveform data variations therein is displayed graphically on a visual display or chart.

5. The mixing system of claim 1 wherein the system provides a sequence of values and waveform data variations therein as a waveform pattern and the waveform is correlated to at least one of the parameters and the sequence of values and variations therein are analyzed as waveform patterns stored in a computer-accessible memory location, displayed on a monitor, printed on paper, or a combination thereof.

6. The mixing system of claim 1 wherein the liquid is water, at least one chemical admixture, or a mixture thereof.

7. The mixing system of claim 1 wherein the drive means is a hydraulic drive, and the sequence of values sensed by the sensor and analyzed by the computer processing unit corresponds to hydraulic pressure require to rotate the mixing drum.

8. The mixing system of claim 1 wherein the determination, storing, and reporting of mixing progress involves the computer processing unit comparing the provided sequence of values with the previously stored sequence of values, and the comparison involves values corresponding to features of “

M”

or “

W”

shaped time-domain waveform, waveform data variations in non-averaged hydraulic pressure, stabilization of averaged hydraulic pressure, or a combination thereof when hydraulic pressure data, corresponding to the energy required to rotate the mixing drum containing concrete, is graphically depicted as a function of time or frequency.

9. The mixing system of claim 1 wherein the waveform data variations compared by the computer processing unit comprise changes in peak amplitude and phase shift in the frequency domain.

10. A mixing system comprising:

a mixing drum having an inner drum wall and at least two mixing blades mounted on the inner drum wall for mixing a provided concrete contained within the mixing drum;

a drive means for rotating the mixing drum containing the provided concrete at constant speed S^C1 in the range of 1-25 revolutions per minute;

a sensor for providing a sequence of values over time corresponding to the energy required by the drive means to rotate the mixing drum, the provided sequence of values enabling a computer processing unit to detect shape transitioning in the waveform data corresponding to concrete flowing over the at least two blades mounted in the drum within one rotational cycle of the mixing drum;

a data memory storage location having waveform data derived from a previously stored sequence of values over time corresponding to the energy required to rotate a mixing drum containing a previous concrete as monitored by a sensor during rotation of the mixing drum at a frequency of at least 10 times constant speed S^C1 of mixing drum rotation, the stored waveform data enabling a computer processing unit to detect shape transitioning in the waveform data corresponding to concrete flowing over the at least two blades mounted in the drum within one rotational cycle of the mixing drum; and

a computer processing unit which performs the following functions;

monitors at a frequency of at least 10 times constant speed S^C1 of mixing drum rotation the sequence of values provided by the energy sensor to obtain waveform data containing shape transitioning in waveform data corresponding to concrete flowing over at least two blades mounted in the drum within one rotational cycle of the mixing drum rotation, and corresponding to the amount of energy required by the drive means to rotate the mixing drum containing the provided concrete;

analyzes the provided sequence of values in the time domain, the frequency domain, or in both the time domain and frequency domain, for variations in waveform data within one rotational cycle of the mixing drum;

compares waveform data variations within the waveform data provided by the sensed sequence of values to waveform data variations within the previously stored sequence of values; and

adjusts the slump, slump flow, or other property of the provided concrete by introducing a liquid into the mixing drum containing the provided concrete based on the comparison of waveform data variations in provided and previously stored sequences of values.

11. The mixing system of claim 10 wherein the waveform data variations are correlated with at least one property or condition of the concrete or mixing drum selected from (a) load weight, (b) load volume, (c) concrete density, (d) concrete air content, (e) concrete slump, (f) concrete slump flow, (g) concrete flow table value, (h) concrete rheology selected from yield stress, viscosity, and thixotropy, (i) segregation of concrete components, (j) concrete setting, (k) inclination of the mixing drum, (I) size and configuration of the internal drum structure;

and (m) build-up of concrete in the drum.

12. The mixing system of claim 11 wherein the waveform data variations are correlated with concrete air content and concrete slump.

13. The mixing system of claim 10 wherein the computer processing unit further compares the calculated variations which were derived from provided and previously stored sequences of values corresponding with concrete slump flow.

14. The mixing system of claim 10 wherein a sequence of values and calculated variations therein is displayed graphically on a visual display or chart as a waveform.

15. The mixing system of claim 10 wherein the system provides a sequence of values and calculated variations therein as a waveform pattern and the waveform is correlated to at least one of the parameters and the sequence of values and variations therein are analyzed as waveform patterns stored in a computer accessible memory location, displayed on a monitor, printed on paper, or a combination thereof.

16. The mixing system of claim 10 wherein the liquid is water, at least one chemical admixture, or a mixture thereof.

17. The mixing system of claim 10 wherein the determination, storing, and reporting of mixing progress involves the computer processing unit comparing the provided sequence of values with the previously stored sequence of values, and the comparison involves values corresponding to features of “

M”

or “

W”

shaped time-domain waveform, calculated variations in non-averaged hydraulic pressure, stabilization of averaged hydraulic pressure, or a combination thereof when hydraulic pressure data, corresponding to the energy required to rotate the mixing drum containing concrete, is graphically depicted as a function of time or frequency.

18. The mixing system of claim 10 wherein the drive means is a hydraulic drive.

19. The mixing system of claim 10 wherein the calculated variations compared by the computer processing unit comprise changes in peak amplitude and phase shift in the frequency domain.