SU816550A1 - Method and apparatus for automatic control of flotation process - Google Patents

Description

The invention relates to automatic control of flotation processes, the regulation of the flow of foaming agent and reagent-collector in coal flotation machines and can be used in the coal and mining industries.

A known method of controlling a flotation machine by continuously measuring the amount of overflowing foam (or measuring the amount of foam using a capacitive sensor installed in the machine above the overflow threshold for foam), which regulate the flow of reagents and aeration of the pulp, or overflow threshold [1J.

The main disadvantage of this method is the low accuracy of regulation due to the lack of information on the physical parameters of the flotation pulp. .

A known method for automatically controlling the flotation process, based on measuring the reflectivity of the pulp and correcting the specific consumption of flotation reagents, a device for which a computing unit, reflectivity sensors and a reagent dispenser rG]., The disadvantage of this method and device is the dependence of light reflected on the surface of the pulp is not not only from the ash content of the pulp, but also from fluctuations in the surface roughness (therefore, the accuracy of measuring the ash content of the flotation tailings is low and up to 3.5 abs.% in ash content. Moreover, the known method and device use only a signal about the quality of one of the flotation products at the output of the flotation machine and do not use information about the dynamics of the processes occurring in the flotation machine itself. As a result, the method and device have low regulation accuracy.

The purpose of the invention is to increase the exact.

regulatory requirements. This goal is achieved by measuring the current values of the relative pulp reflectivity gradients along the height and front of the chambers and adjusting the specific consumption of flotation reagents depending on the measured values.

To this end, a device for implementing the proposed method by a torotor reagent 24. The fiber optic sensor, pulp reflectivity 25 is made in the form of an obliquely cut cylinder, is additionally equipped with two groups of fiber optic pulp reflectivity sensors, a illuminator with a modulator and a photomultiplier, and the group sensors are connected to the illuminator and a photomultiplier flexible optical fibers, while the first group of sensors is installed along the height of the cameras of the flotation machine, and the second oup sensors installed on the front.

In addition, to increase the metrological reliability, the reflectivity sensors are equipped with cleaners made in the form of nozzles interconnected by a common line, which is periodically connected to a high-pressure water line.

Figure 1 shows a block diagram of a device for automatically controlling the flotation process; figure 2 - the location of the light receiving foci in the disk of the illuminator and the scheme of their connection with fiber optic sensors of the reflectivity of the pulp (VDOSP) using hot water in Fig.Z - time diagram of the light flux f in various hot water; figure 4 - installation VDOSP and nozzles on the wall of the chamber of the flotation machine.

The automatic control device (Fig. 1) comprises the VDOSP sensors 2-8 installed on the flotation machine 1, which are connected via the GVS 9 to the respective light-receiving foci 10 installed in the opaque disk 11 with an axial hole. The illuminator consists of a bulb 12, behind which a concave mirror 13 is installed, and a capacitor lens 14 is installed in front of the bulb, with the help of which the disc 11 and all eight receiving receptacles 10 mounted on it from the veto are uniformly mounted, each of which has the shape from the side of the bulb ring sector (figure 2) and connected to the corresponding VDOSP, an electric motor 15, an obturator 16 mounted on the output shaft 17. The obturator has a window 18, the shape and dimensions of which correspond to the shape and dimensions of the light-receiving focus from Rhone bulbs. One of the light-receiving focons has a smaller area than the other seven focons (for example, it has half the central angle of the sector, equal to 12.25 ° instead of 22.5) and using dhw 19 and 20, made of optically transparent material (Fig. .4). Using valves 26 with external thread, seal 27 and nut 28, cylinder 2 is fixed to the chamber wall of the flotation machine so that the cylinder is inside the flotation machine. Optically articulated with cylinder 2 using a seal 27, the inlet GVS-9 and the outlet GVS 20 are fixed in the armature. Next to VDOSP, there is a nozzle 29 with a needle _ valve 30, which is attached with the ° 31 nut to the wall of the flotation chamber chamber.

The device operates as follows.

Light from bulb 12 through the window

18 falls on the light-receiving focon 10 and via hot water supply; 9 is transmitted to the VDOSP. The cutting angle of cylinder 2 is selected so that the angle of incidence of the light beam from the hot water supply 9 to the cutting plane is greater than the angle 25 of total internal reflection. In this case, the light beam from the hot water supply unit 9 falls on the cut plane and passes into the pulp 25, where it undergoes diffusion scattering. The reflectivity of the pulp increases linearly with the growth of ash content of hard fines in it. After scattering in the pulp, part of the light enters the cylinder 2 and the hot water supply 20. Through the hot water supply system 20, the light is transmitted through the focon 21 to the photocathode of the photomultiplier 22. When the shutter 16 is used, which rotates evenly with the electric motor 15, the light through the window alternately through the foci and hot water supply gets to various sensors ^ ⁴⁰ or through one of focons 10 and hot water supply directly to the cathode of the photomultiplier. Fig. 3 shows a time diagram of the light fluxes F in various air forces 19 and 20. At the output of the photomultiplier, a similar time diagram of current is observed with the same period T.

The computing device determines the relative gradients of the reflectivity of the pulp along the height of the chamber, the proportional values of "_ _and H-" ₅ .

similarly along the path of the pulp: ¹ ^ 7- ^ 8 ^ 9 '% <) _ ^ 9 dynamin directly with the light-transmitting focon 21 (Fig. 2), which transmits csei also from VDOSP 2-8 through the dhw 20 to the photomultiplier 22, the output of which is connected to the input of the computing unit 23. The output of the computing unit 23 is connected to a dose of 65

In the process of setting up the device on the flo60 machine, the significance of ve is determined. Coefficients of all relative gradients. K _{2 e} , K _g4 , Κ _4ι 5,

To 5, b,, Κγθ 'and enter these values into the computing unit, which then when the flotation machine gives two values of the weighted relative gradients of the reflectivity of the pulp along the height of the chamber G ₀ and along the path of the skype G _p :

G „. A- [to _g and _m V < ¹ '5 g = - [to 5 Κ _τ . _β Ι ^φ τ-% Ф ²⁾

Depending on the calculated relative gradients, the computational unit 23 implements control signals to the flotation reagent dispenser 24, which responds to the specific consumption of the collector reagent and foaming agent.

From formulas (1) and (2) it is seen that. the value of r ₆ and r _n does not change if the brightness of the bulb or the efficiency of the photomultiplier changes, since all the fluxes Φ (or the currents from the photomultiplier) change the same number of times. Thus, the regulation of the flow of flotation reagents according to the values of the relative gradients Г _в and г _п does not depend on all hardware instabilities, including the same sticking of all the VDOS. If different VDOSP stick in different ways, then the computational values of G _in and G _n will change. To prevent this error, the VDOSP sensors are equipped with batch cleaners, for example, in the form of nozzles mounted near the VDOSP sensors, interconnected by a common line, which is periodically connected to a high-pressure water line. The frequency of · and the duration of the connection depends on the intensity of sticking of the cylinders 2. Connection of the main form. a run to the high-pressure water line is carried out by a signal from the computing unit.

Due to the low cost and small dimensions of the VDOSP, they can be installed in any quantity in arbitrary places of the cameras of the flotation machine. In large flotation machines, sensors for the height of the chamber in several chambers can be installed, and then several relative gradients in height _{в in} and their average value _{0 0} will be determined in the computing unit. Similarly, rows of sensors can be installed at different levels along the path of the pulp through the cameras of the flotation machine.

The proposed method allows you to continuously adjust the flow of flotation reagents according to the dynamics of the process of enrichment of fines in the flotation machine. The regulation of flow rate relative to the relative gradients G _in and G _p does not depend on the instabilities of the elements of the measuring equipment and on the surface roughness of the pulp. During regulation, the information and dynamics of the enrichment processes in various sections of the flotation machine are most fully used. The proposed method and control device involves the use of simple and reliable small-sized fiber-optic sensors of reflectivity of the pulp, allowing you to control the dynamics of processes anywhere in the flotation machine.

Claims (2)

The invention relates to the automatic regulation of flotation processes, the regulation of the consumption of a frother and a collecting agent in coal flotation machines. And it can be used in the coal and mining industries. A known method of controlling a flotation machine is by continuously measuring the amount of overflowing foam (or measuring the amount of foam with a capacitive sensor installed in the machine above the overflow threshold for foam) by which the consumption of reagents and pulp aeration are controlled or the overflow threshold 3 The control accuracy is low due to the lack of information on the physical parameters of the flotation pulp. . A known method for automatically controlling the flotation process, based on measuring the reflectivity of the pulp and correcting the consumption of flotation reagents, is a device for implementing which computing unit, reflectance sensors and reagent dispensers 2. A disadvantage of the known method and device is the dependence of the pulp reflected from the surface light not only from the ash content of the pulp, but also from fluctuations in surface irregularities, therefore, the measurement accuracy of the ash content of flotation tailings is low and is up to 3.5 abs.% in ash content. In addition, the known method and device use only a signal about the quality of one of the flotation products at the flotation machine output and does not use information about the dynamics of the processes occurring in the flotation machine itself. As a result, the method and apparatus have a low adjustment accuracy. The purpose of the invention is to increase the points. regulation. This goal is achieved by measuring the current values of the relative gradients of the reflectivity of the pulp in the height and front of the chambers and the specific consumption of flotation reagents is adjusted depending on the measured values. For this purpose, the device for implementing the proposed method is additionally equipped with two groups of fiber-optic pulp reflectivity sensors, an illuminator with a modulator and a photomultiplier, the group sensors being connected to the illuminator and the photomultiplier by flexible fiber-optic light guides, while the first group of sensors is mounted along the height of the flotation cell chambers, and the second A group of sensors is mounted on the front. In addition, to improve metrological reliability, the reflectance sensors are equipped with purifiers, made in the form of nozzles, interconnected by a common line, which is periodically connected to the water line of the pressure gauge. Figure 1 shows a block diagram of a device for automatically adjusting a flotation process; 2 shows the arrangement of the light-receiving focons in the illuminator disk and the scheme of their connection. With fiber-optic pulp reflectivity sensors (VDOS) using HWS in Fig. 3, there is a time diagram of the light fluxes F in different GWH in Fig. 4 — installation of VDOS and nozzle on the wall of the flotation cell chamber. The automatic control device (Fig. 1) contains sensors VDO 2-8 installed on the flotation machine 1, which are connected to the corresponding light receiving devices with the help of hot water supply system 9. focon 10 installed in the light impermeable disk 11 with an axial hole. The illuminator consists of lambs of the kidney 12, with a concave mirror 13 installed in it, and a condenser lens 14 is installed in front of the bulb, with which the disc 11 is evenly meeting and all eight are mounted on light-receiving focons 10, each of which is shaped from the bulb side sector of the ring (figure 2) and connected to the corresponding VDOS, electromotor 15, obturator 16 mounted on the output shaft 17. The obturator has a window 18, the shape and dimensions of which correspond to the shapes and sizes of the light-receiving focon from the sides s light bulb. One of the light-receiving focons has a smaller area than the other seven focons {for him, for example, half the central angle of the sector, equal to 12.25 °, instead of 22, bj and with the help of HWS 19 and 20, directly from the light transmission line 5 . FOCON 21 (FIG. 2), which also transmits from VDOSP 2-8 through the GVS 20 to the photomultiplier 22, the output of which is connected to the input of the computing unit 23. The output of the computing unit 23 is connected to the flotation reagent meter 24. Fiber optic sensor, pulp reflectivity 25 made in the form of an obliquely cut cylinder from an optically transparent material (figure 4). Using reinforcement 26 with external thread, seal 27 and nut 28, cylinder 2 is fixed to the wall of the flotation cell so that the cylinder is inside the flotation machine. Articulated optically with cylinder 2 with seal 27 in the valve fixes the inlet DHW-9 and outlet DHW 20. Next to VDOS, there is a nozzle 29 with a needle valve 30, which is fastened with a nut 31 to the wall of the flotation cell. The device works as follows. The light from the light bulb 12 through window 18 falls on the light-receiving focon 10 and through the DHW; 9 is transmitted to VDOP. The cut-off angle of cylinder 2 is chosen so that the angle of incidence of the light beam from DHW 9 on the cut-off plane is greater than the angle of total internal reflection. At the same time, a beam of light from HWS 9 enters the plane of the cut and passes into the bullet 25, where it undergoes diffusion scattering. The pulp reflectivity increases linearly with dew. tom ash solid stuff in it. After scattering into the pulp, part of the light enters back into cylinder 2 and DHW 20. Through DHW 20, light is transmitted through focal 21 to the photocathode of photomultiplier 22. When the shutter 16 is in operation, which rotates uniformly with the help of electric motor 15, through window 18, the light alternately through focons and GVS falls on various sensors or through one of the focons 10 and GVS 19 directly to the cathode of the photomultiplier. Fig. 3 shows the temporal diagonal of the light fluxes Φ in different air forces 19 and 20. At the output of the photomultiplier, a similar time diagram of the current with the same period T is observed. The computing device determines the relative gradients of the reflectivity of the pulp over the height of the chamber, proportional. F ,, -. "four-. 19 Ю 19 similarly along the path of the pulp:, df, 19 In the process of setting up the devices on the flotation machine, the significance of the ve is determined. sovoy coefficients of all relative gradients. K2 3 K .5 /. To 5,6 t К-гз and enter these values into the computing unit, which then, when the flotation machine is operating, gives two values of the weighted relative gradients of the reflectivity of the pulp along the height of chamber и and along the path of the pulp Γ ":, .Л- F,) K ,, 1Fg, L. Depending on the computed relative gradients of the computed values, the computing unit 23 distributes control signals to the flotation reagent dispenser 24, which reacts to the specific costs of the collector reagent and foamer. It can be seen from formulas (.1) and (2) that the value of r and r does not change if the brightness of the light bulb or the efficiency of the photomultiplier changes, so that all fluxes Φ (or currents from the photomultiplier) change by the same number of times. Thus, the regulation of the flow of flotation reagents according to the relative gradients of Hz and Tfj does not depend on all instrumental instabilities, including the same sticking of all VDOPs. If different VDOPs are sticking differently, the computational values of Tg and Fq change. To prevent this error, VDOS sensors are equipped with periodic-effect cleaners, for example, in the form of nozzles installed near VDOS sensors interconnected by a common line, which is periodically connected to a high-pressure water line. The frequency and duration of the connection depends on the intensity of sticking of the cylinders 2. The nozzle line is connected to the high pressure water line by a signal from the computing unit. Due to the low cost and small dimensions of VDOS, they can be installed in any quantity in arbitrary locations of the cameras of the photomachine. In large flotation machines, sensors can be mounted on the height of the chamber in several chambers, and then several relative gradients of height Hz and their average Hz value will be determined in the computing unit. Similarly, rows of sensors at different levels can be installed along the path of the pulp through the flotation chambers. The proposed method allows continuously adjusting the flow of flotation reagents according to the dynamics of the enrichment process in the flotation machine. . Flow regulation by the magnitudes of relative gradients Γ and Γ does not depend on the instabilities of the elements of the measuring apparatus and on the roughness of the surface of the pulp. In the regulation, the information and the dynamics of the enrichment processes in various areas of the flotation machine are used most fully. The proposed method and device for regulation implies the use of simple and reliable small-sized fiber-optic pulp reflectance sensors, which allow controlling the dynamics of processes in any place of the photomachine. Claim 1. Method for automatic control of the flotation process based on measuring the reflectivity of the pulp and correcting the specific consumption of flotation reagents, characterized in that, in order to improve the control accuracy, the current values of relative gradients of reflectance of the pulp in terms of height and front are measured. chambers, and the specific consumption of flotation reagents are adjusted depending on the measured values. 2. A device for carrying out the method of claim 2, comprising a computing unit, reflectivity sensors and a flotation reagent dispenser, characterized in that it is additionally equipped with two groups of fiber-optic pulp reflectivity sensors, an illuminator with a modulator and a multiplier, and the sensors of groups they are connected to the illuminator and the photomultiplier by flexible fiber-optic light guides, with the first group of sensors mounted along the height of the cells of the photomachine and the second group of sensors along the front of the cameras. 3. The device according to claim 2, which is designed to ensure that, in order to increase metrological reliability, the reflectance sensors are equipped with cleaners made in the form of nozzles connected by a common magistrail, which. The torus is periodically connected to a high pressure water main. Sources of information taken into account in the examination 1. Patent IT 3471010, cl. 209-1, published. 1971. 2. Diamonds V. V. Automation of coal preparation plants and instrumentation. M., Nedra, 1977, p. 223-226. 515 W W W W  .