초록 ▼

Methods are provided for determining an estimated volumetric ratio of a material to total materials in a mixing vessel. In various embodiments, the methods may comprise: summing a commanded input flowrate of the material and a volumetric disturbance flowrate of the material being fed to the mixing v

Methods are provided for determining an estimated volumetric ratio of a material to total materials in a mixing vessel. In various embodiments, the methods may comprise: summing a commanded input flowrate of the material and a volumetric disturbance flowrate of the material being fed to the mixing vessel; estimating the output flowrate of the material exiting the mixing vessel; negatively feeding back the estimated output flowrate of the material to obtain an estimated volumetric rate of change of the material in the mixing vessel; and integrating the estimated volumetric rate of change of the material to compute the estimated volumetric ratio of the material to the total materials in the mixing vessel.

대표청구항 ▼

What is claimed is: 1. A method of operating a computer control system for a mixing vessel to determine an estimated volumetric ratio of a material to total materials in a mixing vessel, comprising: summing a commanded input flowrate of the material and a volumetric disturbance flowrate of the mate

What is claimed is: 1. A method of operating a computer control system for a mixing vessel to determine an estimated volumetric ratio of a material to total materials in a mixing vessel, comprising: summing a commanded input flowrate of the material and a volumetric disturbance flowrate of the material being fed to the mixing vessel; estimating the output flowrate of the material exiting the mixing vessel based on the summed commanded input flowrate and the volumetric disturbance flowrate; negatively feeding back the estimated output flowrate of the material to obtain an estimated volumetric rate of change of the material in the mixing vessel; and integrating the estimated volumetric rate of change of the material to compute the estimated volumetric ratio of the material to the total materials in the mixing vessel; wherein the mixing process computer control system controls the mixing process volumetrically utilizing the estimated volumetric ratio of the material to control at least one input valve. 2. The method of claim 1, further comprising dynamically recomputing the estimated output flowrate of the material. 3. The method of claim 1, wherein said integrating is performed by a feedback control loop. 4. The method of claim 3, wherein the feedback control loop comprises gain elements for multiplying the Laplace transform for integration, 1/s, by 1/(an estimated total volume in the mixing vessel) and by an estimated total output flowrate. 5. The method of claim 3, further comprising computing a difference between an estimated total volumetric disturbance flowrate and the volumetric disturbance flowrate of the material to obtain an estimated volumetric disturbance flowrate for other materials in the mixing vessel. 6. The method of claim 5, further comprising estimating the output flowrate of a second material exiting the mixing vessel. 7. The method of claim 6, further comprising negatively feeding back the estimated output flowrate of the second material. 8. The method of claim 7, further comprising computing a summation of the estimated volumetric disturbance flowrate of the other materials, a commanded input flowrate of the second material, and the negatively fed estimated output flowrate of the second material, thereby obtaining an estimation of a volumetric rate of change of the second material in the mixing vessel. 9. The method of claim 8, further comprising integrating the estimated volumetric rate of change of the second material to compute an estimated volumetric ratio of the second material to the total materials in the mixing vessel. 10. The method of claim 9, further comprising dynamically recomputing the estimated output flowrate of the second material. 11. The method of claim 9, wherein said integrating the estimated volumetric rate of change of the second material is performed by a second feedback control loop. 12. The method of claim 6, wherein the material comprises water and the second material comprises cement. 13. The method of claim 1, wherein the total materials comprise a liquid and a gas-transported dry material. 14. The method of claim 1, wherein the volumetric disturbance flowrate of the material is determined by comparing a measured input flowrate of the material to the commanded input flowrate of the material. 15. A method of operating a computer system for a first and second mixing vessel to determine an estimated volumetric ratio of a material to total materials in the second mixing vessel that is partially separated from the first mixing vessel, comprising: summing a commanded input flowrate of the material and a volumetric disturbance flowrate of the materials being fed to the first mixing vessel; estimating an output flowrate of the material exiting the first mixing vessel based on the summed commanded input flowrate and the volumetric disturbance flowrate; negatively feeding back the estimated output flowrate of the material to obtain an estimated volumetric rate of change of the material in the first mixing vessel; integrating the estimated volumetric rate of change of the material in the first mixing vessel to dynamically recompute the estimated output flowrate of the material exiting the first mixing vessel; estimating an output flowrate of the material exiting the second mixing vessel based on the recomputed estimated output flowrate of the material exiting the first mixing vessel; negatively feeding back the estimated output flowrate of the material exiting the second mixing vessel and summing it with the estimated output flowrate of the material exiting the first mixing vessel, thereby obtaining an estimated volumetric rate of change of the material in the second mixing vessel; and integrating the estimated volumetric rate of change of the material in the second mixing vessel to compute the estimated volumetric ratio of the material to the total materials in the second mixing vessel; wherein the mixing process computer system controls the mixing process within each respective mixing vessel volumetrically utilizing at least one of the respective estimated volumetric ratios of the materials to control at least one input valve. 16. The method of claim 15, further comprising measuring an output flowrate of the total materials exiting the second mixing vessel. 17. The method of claim 15, further comprising dynamically recomputing the estimated output flowrate of the material exiting the second mixing vessel. 18. The method of claim 15, wherein said integrating the estimated volumetric rate of change of the material in the first mixing vessel and said integrating the estimated volumetric rate of change of the material in the second mixing vessel are performed by respective first and the second feedback control loops. 19. A method of operating a computer control system to determine an estimated volumetric ratio of a second material to total materials in a first mixing vessel that is partially separated from a second mixing vessel, comprising: measuring a height of the total materials in the second mixing vessel; comparing the height of the total materials in the second mixing vessel to a summation of an estimated height of a first material in the second mixing vessel and an estimated height of the second material in the second mixing vessel to obtain an estimation of a height error for the second mixing vessel; feeding the estimated height error to a controller to compute an estimated volumetric disturbance flowrate of the second material; computing a summation of (a) a commanded input flowrate of the second material to the first mixing vessel, (b) the estimated volumetric disturbance flowrate of the second material, and (c) a negative value of an estimated output flowrate of the second material from the first mixing vessel, thereby obtaining an estimated volumetric rate of change of the second material in the first mixing vessel; and integrating the estimated volumetric rate of change of the second material to obtain the estimated volumetric ratio of the second material to total materials in the first mixing vessel; wherein the mixing process computer control system controls the mixing process within each respective mixing vessel volumetrically utilizing the estimated volumetric ratio of the second material to control at least one input valve.