Settling process analysis device and method

• US 5,635,632 A
• Filed: 04/26/1994
• Issued: 06/03/1997
• Est. Priority Date: 04/26/1994
• Status: Expired due to Fees

• Current Assignee: Cytec Technology Corp.
• Original Assignee: Cytec Technology Corp.
• Inventors: Fay, Charles R., Robinson, Harold L., Barnes, Ralph W.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Oda, Christine K.
• Application Number:
  US08/233,178
• Time in Patent Office: 1,134 Days
• Field of Search: 73/61.65, 73/61.63, 73/1 DV, 73/61.75, 73/270 V
• US Class Current: 73/61.63
• CPC Class Codes: G01N 15/04 Investigating sedimentation of particle suspensions
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/017 Doppler techniques
• CPC Class Codes: G01N 2291/02416 Solids in liquids
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 29/032 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/40 by amplitude filtering, e.g. by applying a threshold or by gain control
• CPC Class Codes: G01N 29/4481 Neural networks

Abstract

A system and method for monitoring the dynamics of particle motion in a liquid-solid media including the rate of settling of particles, the identification of unsettled particle clouds, and the identification of unsettled particle clouds, and the identification and control of the bed level of settled particles in a slurry within a settler. The system includes an ultrasound transducer and a receiver for detecting echoes from particles in the slurry. The echoes are processed to determine the bed level of the settled particles, the position of unsettled particle clouds, and the rate of settling of the particle clouds.

Claims

1. A method for locating the bed level of settled particles within a liquid slurry comprising,

transmitting ultrasonic sound waves into a slurry of particles to generate echoes from said particles,

generating analog electrical signals from said echoes,

multiplying said analog electrical signals by any of sine or cos signals to produce second analog signals,

generating digital electrical signals from said second analog signals, and

processing said digital electrical signals to identify a bed level of settled particles.

2. The method of claim 1 wherein said processing is performed by at least one of Doppler method, peak method or moving target method.

3. A method for locating the bed level of settled particles within a liquid slurry comprising,

transmitting ultrasonic sound waves into a slurry of particles to generate echoes from said particles,

generating electrical signals from said echoes and

processing said electrical signals to identify a bed level of settled particles by peak method comprising the steps of:

dividing the signals from said echoes into sine and cosine channels;

multiplying the signals in the sine channel by a sine signal of the same frequency as the ultrasonic sound waves;

multiplying the signals in the cosine channel by a cosine signal having the same frequency as the ultrasonic sound waves;

converting the signals in each of the sine and cosine channels to digital signals;

storing the digital signals according to transducer lines in memory;

assigning the highest echo amplitude from all the transducer lines as a function of depth to one or more result lines for each channel;

constructing a combined result line from one or more result lines and

locating the bed level by identifying the highest value on the combined result line.

4. A system for determining the bed level of settled particles in a slurry comprising,

a means for sending ultrasound signals into a slurry,

a means for receiving echoes caused by the reflection of the ultrasound signals from solid particles in the slurry,

means for converting said echoes to a first set of analog electrical signals;

means for multiplying said first set of analog signals with sine or cos signal to generate a second analog signal;

a means for multiplexing said second analog signals to a means for converting said analog signals to digital signals; and

a data acquisition memory for storing the digital signals for numerical processing.

5. The system of claim 4 further comprising a range phase cancellation memory.

6. The system of claim 5 further comprising a means for controlling said means for multiplexing to provide for selective sampling of portions of said second analog signals.

7. The system of claim 4 wherein said numerical processing is by at least one of Doppler method, peak method or moving target method.

8. A device for controlling the bed level of a settling tank comprising the system of claim 4,

wherein said system generates electrical signals to control means for depositing chemical additives and slurry additions to a settling tank.

9. A method for identifying an unsettled particle cloud within a settling tank comprising,

transmitting ultrasonic sound waves into a slurry of particles to generate echoes from said particles;

generating electrical signals from said echoes;

dividing said electrical signals into sine and cosine channels;

multiplying the electrical signals in the sine channel by a sine signal of the same frequency as the ultrasound sound waves to provide a sine channel result;

multiplying the electrical signals in the cosine channel by a cosine signal of the same frequency as the ultrasound sound waves to provide a cosine channel result;

converting the electrical signals in said channels to digital signals;

storing the digital signals according to transducer lines in memory;

subtracting the digital signals from each transducer line from a succeeding transducer line on a depth-by-depth basis;

summing absolute values of differences between the transducer lines in each channel; and

constructing a combined result line from said absolute values by determining the square root of the sum of the squares of sine channel results and the squares of cosine channel results; and

locating particle clouds by identifying deviations from a baseline of the combined result line.