Granted Patent B2

US 12,636,655 · App. 18/553,983 · Granted May 26, 2026

Inventor: Tim Sundström (Åkers Styckebruk, SE)

Assignee: S.P.M. Instrument AB

B02C17/1805G01H1/003

Abstract

Claims (96)

1 . A method of operating a comminution process in a ball mill including a rotatable shell having an internal shell surface with a first number of protrusions configured to engage a charge of material for grinding received solid material feed particles by tumbling the material in the rotating shell so as to generate product particles at a mill output, thereby causing a vibration having a first repetition frequency dependent on a speed of shell rotation when a protrusion engages with a toe portion of said material;

the method comprising:

rotating the shell at the speed of shell rotation during operation of the ball mill;

providing a solid material feed rate set point value for setting a solid material feed rate;

said solid material feed rate being an amount per time unit, of said feed particles, that is being fed into an input of the ball mill thereby influencing an internal state of said comminution process;

analyzing at least a portion of said product particles;

generating at least one product measurement value based on said analyzing at least a portion of said product particles; said at least one product measurement value being indicative of a product particle median size;

receiving a vibration signal indicative of said vibration;

receiving a position signal indicative of a rotational position of said rotating shell;

generating, based on said vibration signal and said position signal, at least one status parameter value indicative of said internal state; said at least one status parameter value including

a toe position value indicative of a position of the toe portion;

receiving data indicative of a desired product particle median size and/or desired product particle size distribution;

generating a status parameter reference value based on said data indicative of said desired product particle median size and/or desired product particle size distribution, and

a correlation data set; said correlation data set indicative of a causal relationship between said at least one status parameter value;

and said at least one product measurement value and/or correlation data set indicative of a causal relationship between said internal state of said comminution process and said product particle size distribution;

said at least one status parameter reference value including a toe position reference value; and

controlling via a regulator said product particle size distribution based on said at least one status parameter reference value,

said at least one status parameter value, and

at least one status parameter error value,

wherein said at least one status parameter error value depends on said at least one status parameter reference value, and

said at least one status parameter value.

2 . The method according to claim 1 , wherein

said position signal has a second repetition frequency dependent on said speed of rotation; and

said vibration signal includes a time sequence of vibration sample values; the method further comprising

detecting, in said time sequence of vibration sample values, an event signature having an event signature occurrence frequency, said event signature occurrence frequency being equal to said first repetition frequency;

generating, based on said event signature occurrence frequency, a periodic event signal exhibiting a first number of periods per revolution of said shell during operation of the tumbling mill;

generating, based on said position signal, a periodic reference signal exhibiting said first number of periods per revolution of said shell during operation of said tumbling mill;

generating data indicative of a first temporal relation; between said periodic event signal, and said periodic reference signal; said temporal relation being indicative of said internal state of the tumbling mill.

3 . The method according to claim 2 , further comprising

detecting, in a time sequence of position signal values, a first occurrence of a first reference position signal value indicative of a predetermined rotational position of said rotating shell;

providing a reference signal based on said position signal such that said reference signal is provided a certain number of times per revolution of said shell; and

detecting, in said vibration signal, a signal event signature that occurs when a said internal protrusion engages with a toe portion of said material;

measuring a first duration from a provision of a first reference signal to a provision of a subsequent reference signal; and

measuring a second duration between the provision of a reference signal to the occurrence of a subsequent said signal event signature, or measuring the second duration between the occurrence of said signal event signature to the provision of the subsequent reference signal; and

generating a temporal relation value based on said second duration and said first duration; said temporal relation value being indicative of said internal state of the tumbling mill.

4 . The method according to claim 3 , wherein

said toe position value is said first temporal relation as defined in claim 3 , or wherein

said toe position value is said temporal relation value as defined in claim 3 .

5 . The method according to claim 4 , further comprising

providing a ball feed rate set point value for setting a ball feed rate;

said ball feed rate being an amount of grinding balls per time unit that is being fed into an input of said ball mill for enhancing said comminution process, said grinding balls thereby influencing said internal state of said comminution process.

6 . The method according to claim 5 , further comprising

receiving, via a user interface, fourth user input relating to said ball feed rate;

generating said ball feed rate set point value thereby influencing said internal state (X) for controlling or affecting said product particle median size;

wherein said generated ball feed rate set point value is based on said received fourth user input.

7 . The method according to claim 6 , further comprising

detecting, in said vibration signal, a signal event signature that occurs when a said internal protrusion engages with said toe portion of said material;

said event signature being indicative of an impact force generated when a protrusion on an internal shell surface of the rotating shell interacts with a toe portion of the charge material.

8 . The method according to claim 7 , further comprising

generating yet another status parameter value based on said impact force;

said yet another status parameter value, when generated at the speed of shell rotation and at the toe position value,

being indicative of a mass of said charge of material.

9 . The method according to claim 8 , further comprising

generating said ball feed rate set point value based on a combination of said impact force and said toe position value and said speed of shell rotation.

10 . The method according to claim 1 , further comprising:

generating and/or updating said correlation data set based on:

said toe position value, measured product particle median size, and said speed of shell rotation; and/or said at least one status parameter value indicative of internal state,

measured product particle size distribution, and

said speed of shell rotation.

11 . A computer program product comprising a non-transitory computer-readable storage medium having thereon a computer program comprising program instructions, the computer program being loadable into a processor and configured to cause the processor to perform the method according to claim 1 .

12 . A system comprising:

a tumbling mill configured to perform a comminution process, the tumbling mill being a ball mill having a shell that is rotatable around an axis at a speed of rotation for grinding a charge of material by tumbling the material together with a number of grinding balls in the rotating shell so as to generate product particles; said shell having an internal shell surface including a first number of protrusions configured to engage material and/or grinding balls when the shell rotates about the axis, thereby causing a vibration having a first repetition frequency dependent on said speed of rotation;

the ball mill comprising:

a first feed inlet for receiving, at a solid material feed rate, a solid feed material for grinding; said solid material feed rate being an amount of solid material feed particles per time unit that is being fed into an input of the tumbling mill thereby influencing an internal state of said comminution process; said solid material feed rate being controlled or set by a solid material feed rate set point value; the solid feed material feed particles having a feed particle size distribution;

a ball feed inlet for receiving, at a ball feed rate, said grinding balls for enhancing said grinding; said ball feed rate being an amount of grinding balls per time unit that is being fed into a feed ball inlet of the tumbling mill thereby influencing said internal state of said comminution process; said ball feed rate being controlled or set by a ball feed rate set point value;

a mill output for delivery of said product particles; said product particles having a product particle size distribution; said product particle size distribution being different from said feed particle size distribution;

a vibration sensor for generating a signal indicative of said vibration;

a position sensor for generating a signal indicative of a rotational position of said rotating shell; and

a monitoring module being configured to receive data indicative of said vibration signal; and data indicative of said position signal;

the monitoring module including:

a status parameter extractor configured to generate at least one status parameter value indicative of an internal state of said comminution process based on said vibration signal and said position signal; said at least one status parameter value including a toe position value; and

a product analyser configured to analyse at least a portion of said product particles; said analyser being configured to generate at least one product measurement value based on the analysing of said at least a portion of said product particles; said at least one product measurement value being indicative of a product particle median size;

the system further comprising:

a reference value generator having an input configured to receive data indicative of a desired product particle size distribution, said reference value generator being configured to generate at least one status parameter reference value based on said data indicative of said desired product particle size distribution, and

correlation data indicative of a causal relationship between said at least one status parameter value, and

said at least one product measurement value and/or

correlation data indicative of a causal relationship between

said internal state of said comminution process and

said product particle size distribution;

said at least one status parameter reference value including a toe position reference value; and

a regulator for controlling said product particle size distribution based on

said at least one status parameter reference value,

said at least one status parameter value, and

at least one status parameter error value,

wherein

said at least one status parameter error value depends on said at least one status parameter reference value, and

said at least one status parameter value.

13 . The system according to claim 12 , wherein said at least one status parameter error value depends on a difference between said at least one status parameter reference value and said at least one status parameter value; wherein said at least one status parameter reference value includes said toe position reference value, and said at least one status parameter value includes said toe position value.

14 . The system according to claim 13 , wherein, a set point value vector includes said set point values;

a reference value vector includes said status parameter reference values;

an internal state vector includes said internal state values;

an output value vector includes said product measurement values; and/or

an error value vector includes said error values.

15 . The system according to claim 14 , wherein said regulator is configured to generate said solid material feed rate set point value, thereby controlling said product particle size distribution.

16 . The system according to claim 15 , wherein said regulator is configured to generate said set point value vector, thereby controlling said output value vector; said regulator generating said set point value vector based on said reference value vector, said internal state vector, and said error value vector.

17 . The system according to claim 12 , further comprising a correlator configured to perform correlation of said at least one product measurement value and said at least one status parameter value; wherein said correlator is arranged to generate correlation data indicative of a causal relationship between said at least one status parameter value and said at least one product measurement value and/or correlation data indicative of a causal relationship between said internal state of said comminution process and said product particle size distribution.

Assignments (1)

Priority Claims (1)

Continuity (2)

References Cited (400)