Direct visual monitoring method and system for sensing the interior of a rotary mineral mill

1. A direct visual monitoring system for sensing an interior of a rotary mineral mill, said system comprising:

a monitoring unit to be mounted on a discharge zone of a feed hopper of a vessel;

a main control unit; and

an operation and management unit, wherein

the rotary mineral mill is fed from a vessel through the feed hopper, and

a location of the monitoring unit on the discharge zone of the feed hopper is adjustable according to a dimension of said feed hopper and in accordance with a dimension of the rotary mineral mill, so as to allow for a direct view of the interior of the rotary mineral mill, and

the monitoring unit is subject to vibrations during loading of the mill and determines a load passing below the monitoring unit, and the monitoring unit comprises an outer housing having a defined shape given by a volume occupied on the feed hopper and protects a container of sensors which are visually oriented towards the inside of the mill.

2. The monitoring system as in claim 1 , wherein the outer housing is built with a steel shielding and at least one of a rubber lining for absorbing impact, and passive shock absorbers for absorbing vibrations, and active shock absorbers.

3. The monitoring system as in claim 1 , wherein the container of sensors which are visually oriented towards the inside of the mill comprises sensors arranged in said container of sensors, the sensors including at least one of a laser scanner, a thermographic camera, a digital camera, a plurality of illumination means, a thermocouple and an accelerometer.

4. The monitoring system as in claim 3 , wherein the thermocouple generates a continuous voltage signal which value is related to a temperature, this temperature signal includes information related to behavior of the temperature in time and alert in regard to operation of the mill, whether manually or automatically, in relation to temperature conditions not so appropriate for the operation of the rest of the sensors inside the container of sensors and for controlling conditioning air flow in its interior and maintaining an adequate temperature for the operation of the sensors located inside the container of sensors through the openings for the climate air to enter and one for the climate air to exit.

5. The monitoring system as in claim 3 , wherein the accelerometer generates a digital signal containing variables according to the time, proportional to the acceleration in a vertical axis, a horizontal axis and a front horizontal axis of the mill, said digital signal indicates behavior of the vibration in the vertical axis, the horizontal axis and the front horizontal axis in time and alerting operation of the mill, whether manually or automatically, with regard to vibration conditions for operation of the sensors inside the container of sensors and for controlling rigidity of the active shock absorbers on which the container of sensors is supported, thus maintaining an appropriate vibration level for the operation of the sensors inside the container of sensors.

6. The monitoring system as in claim 1 , wherein the laser scanner executes a detection of distance in one or more planes by using laser beams which are moved in angle in time by a mirror rotating at high speed, for obtaining one or more three-dimensional geometric profiles of the surrounding in predefined angle positions, the laser scanner obtains the three-dimensional geometric profiles at an appropriate frequency during operation of the mill, values in the time of distance and angle of each laser beam, generated by the laser scanner, are automatically stored and processed for analysis procedures for measuring spatial positions and dimensions of elements of interest inside the mill, for detecting the presence or absence of elements, for detecting integrity of constituent parts of liner, and/or for determining location of load of a geometric profile of its surface and its volume.

7. The monitoring system as in claim 1 , wherein the digital camera obtains two-dimensional images from the interior of the mill in visible spectrum through a lens with appropriate optical characteristics the geometric conditions of the mill, the digital camera has appropriate characteristics for movement speed of load in the mill, and for the illumination produced by the illumination means, the digital camera obtains photographs at a predetermined frequency for the operation of the mill,

wherein the images captured by the digital camera are automatically stored and processed to measure dimensions of elements of interest inside the mill, for detecting the presence or absence of elements, for detecting integrity of constituent parts of liner, and/or determining location of load and a geometric profile of its surface.

8. The monitoring system as in claim 1 , wherein the thermographic camera obtains two-dimensional images of the interior of the mill in the thermal spectrum, color or tonality of each pixel of the two-dimensional images is related to the temperature of a photographed object, the two-dimensional images are captured by a lens having appropriate optical characteristics for geometric conditions of the mill, the lens is protected by a window made of a thermal frequency permeable material, the thermographic camera obtains thermal images at a predetermined frequency during operation of the mill, the thermal images are automatically stored and processed for analysis procedures allowing a redundant measurement and identifying abnormal thermal gradients in the components pieces of the liner of the mill for identifying structural failure points while searching for in the load elements in comparison with the rest thus determining the relative presence and quantity of steel balls according to mineral quantity.

9. The monitoring system as in claim 3 , wherein the container of sensors has a face oriented towards the interior of the mill and has a display panel containing perforations with a shape for each sensor, the perforations including a scanner opening for the laser scanner, a thermal opening for the thermographic camera, an illumination opening for the digital camera, the illumination opening is defined by an arrangement being adopted when the digital camera is calibrated for a better visual approach towards the inside of the mill, illumination means is arranged at a side, below, above or surrounding the digital camera to illuminate the mill.

10. The monitoring system as in claim 9 , wherein the display panel has in its upper part a visor which is hollow and that is integrated into the container of sensors, which is internally connected to a clean air duct under pressure; wherein air injected by the air duct under pressure flows through the visor and exits through a plurality of orifices, thereby generating a plurality of air jets flowing from a top of the visor towards a bottom maintaining an external face of the display panel clean, and preventing the sensors and the illumination means from being embed.