CN103438934A - Method and device for detecting load parameters of ball mill - Google Patents

Abstract

The invention relates to a method and a device for detecting load parameters of a ball mill, belonging to the field of automatic detection. Combine the measured resistance value of the load body, the measured weight of the ball mill barrel, and the ball mill barrel speed, and accurately calculate the filling rate, loading capacity, and ball-to-material ratio of the ball mill through multiple mathematical models. The ball mill cylinder of the device is suspended and fixed on the frame and measured by the load cell. The bottom of the ball mill cylinder is equipped with electrodes, and the position sensor and rotary encoder are fixed at the bottom of the frame. The position sensor and rotary encoder collect The signal is transmitted to the computer through the DI module, the resistance value signal collected by the electrode and the ball mill cylinder is transmitted to the computer through the resistance A/D module, wireless transmitter and wireless receiver, and the weight signal of the ball mill cylinder collected by the load cell is transmitted to the computer. The invention is the premise of realizing the optimal control of the ball mill, and plays an important role in improving the efficiency of the ball mill, reducing energy consumption and the like.

Description

A method and device for detecting load parameters of a ball mill

technical field

The invention relates to a method and device for detecting load parameters of a ball mill, specifically combining the measured resistance value of the load body, the measured weight of the ball mill cylinder, and the rotational speed of the ball mill cylinder, and accurately calculating the filling rate of the ball mill through multiple mathematical models. The composite technical method of loading capacity and ball-to-material ratio belongs to the field of automatic detection.

Background technique

Ball mills are widely used in mining, metallurgy, chemical industry, building materials, electric power, ceramics and other industries, especially in the beneficiation process of mines. Wet ball mill is the most commonly used crushing equipment in mineral processing industry. The internal load body of the wet ball mill is composed of steel balls, materials and water. The filling rate refers to the ratio of the space occupied by the load body inside the ball mill cylinder. The ball-to-material ratio refers to the ratio of the mass of steel balls loaded inside the ball mill cylinder to the material mass. The filling rate and the ball-to-material ratio are the two most important indicators to reflect the load of the ball mill. Important parameter, directly related to crushing efficiency. Practice has shown that keeping the ball mill running at a reasonable filling rate and ball-to-material ratio can not only greatly increase the processing capacity of the ball mill, reduce the consumption of unit processing capacity, but also play a very important role in improving the production indicators of the entire concentrator .

Traditional single-factor load parameter detection methods mainly include: current method, acoustic method, useful power method, vibration method, etc. Although these methods are simple and easy to implement, due to the limitation of the detection principle, they can only indirectly reflect the single load parameter of the ball mill, and cannot accurately detect the load parameter of the ball mill in the whole process alone.

Considering the advantages and disadvantages of a single detection method, two or three complementary detection methods are combined to detect load parameters, and the sound-power double signal detection method, sound-vibration double signal detection method, sound- Power-vibration three-signal detection method and other multi-factor detection methods. These methods are very complicated to calculate, have poor adaptability, and are easily affected by factors such as grinding concentration, material particle size, material hardness, and steel ball size.

The force sensor method is a technical method that uses a force sensor to directly measure the force related to the load of the ball mill to detect the load parameters of the ball mill. At present, there are mainly liner pressure detection method, cylinder stress detection method, cylinder weighing detection method, etc. The liner pressure detection method is to install a sensor capable of measuring radial pressure and tangential pressure under the inner liner of the ball mill cylinder, and the measurement signal is introduced into the computer for processing to obtain a force map, from which the detachment of the load body of the ball mill can be judged Angle and contact angle, from which the filling rate of the ball mill can be calculated, and then the radial pressure can be analyzed to calculate the ball-to-material ratio. The weighing method can accurately detect the loading capacity of the ball mill, with few affected factors and strong adaptability, but it cannot detect the filling rate and ball-to-material ratio.

Judging from related reports, the existing ball mill load parameter detection methods are more or less deficient, some factors cannot be accurately detected, some calculations are too complicated or the conditions are harsh and difficult to apply, and some detection parameters are not very accurate. Comprehensive, difficult to apply to the optimal control of ball mills.

Contents of the invention

In order to overcome the shortcomings of the existing ball mill load parameter detection method, such as low detection accuracy, overly complicated calculation, and incomplete detection parameters, the present invention provides a ball mill load parameter detection method and device, which can not only simultaneously detect the The filling rate, loading capacity and ball-to-material ratio of the load body are highly adaptable and easy to realize.

Technical scheme of the present invention is:

(1) Detect the no-load mass of the ball mill, and then detect the total mass of the ball mill after adding the load body when testing the abrasive, and calculate the loading capacity of the ball mill;

(2) Install the electrodes on the barrel of the ball mill. During the operation of the ball mill, measure the resistance between each electrode and the barrel, and the position angle of each electrode. Take the position angle of each electrode as the abscissa and the The resistance value is the ordinate, and the resistance value map of the electrode is respectively established, and the detachment angle θ _A and the contact angle θ _B of the electrode position of the load body are judged according to the change rule of the resistance value, and the detachment angle θ _A and the contact angle θ _B are respectively calculated for each The filling rate of the local load body at the electrode position is calculated by the weighted average method to calculate the overall filling rate of the ball mill;

(3) According to the overall filling rate and loading capacity of the ball mill, combined with the ore density and the pulp density after adding water to the ore, the ball-to-material ratio of the load body is calculated through the ball-to-material ratio mathematical model, which is the load parameter of the ball mill. Filling ratio and ball-to-material ratio are important parameters that affect the crushing efficiency of the ball mill. If the filling rate is too low, there will be less ore available for crushing, so the crushing efficiency is low; if the filling rate is too high, the movement of the steel balls inside the ball mill to strike the ore particles will become weak, and the crushing efficiency will be low; in addition, the ball mill relies on the collision of steel balls If there are more steel balls and less ore, the electric energy will be mainly consumed in the interaction of steel balls. If there are fewer steel balls and more ore, the ore will be less likely to be impacted by steel balls or ground. Electric energy is mainly consumed in the circular motion of the load body. Therefore, the filling rate and ball-to-material ratio of the ball mill must be controlled in the best state to obtain the best grinding effect. However, the detection of the filling rate and the ball-to-material ratio of the present invention is the premise of realizing the optimal control of the ball mill.

The calculation method of the loading capacity of the ball mill is: first detect the no-load mass of the ball mill, and then detect the total mass after adding ore pulp and steel balls during the ball mill, and subtract the no-load mass from the total mass to obtain the loading capacity of the ball mill.

The load body is a mixture of steel balls, ore and water in the barrel of the ball mill.

There are at least three electrodes installed on the barrel of the ball mill, which are installed at different positions of the barrel.

There are three or five electrodes installed on the ball mill cylinder, which are installed at the front, middle and rear ends of the bottom of the ball mill cylinder.

The method for measuring the position angle of the motor of the ball mill cylinder is as follows: install a rotary encoder on the surface of the ball mill cylinder to detect the rotational speed of the ball mill, install a position sensor under the ball mill cylinder, and when the electrode passes the position sensor, a The electric pulse determines the zero angle of the electrode (the position of the position sensor is the zero angle), and the electrode position angle can be calculated by the angular velocity of the cylinder and the time when the electrode passes through the zero angle.

The modeling method of the mathematical model of the ball-to-material ratio is: calculate the volume of the internal load body of the ball mill according to the overall filling rate, and then combine the loading capacity, ore density, steel ball density, and ore slurry concentration to deduce the ball-to-material ratio through the mechanism analysis method The preliminary mathematical model, and then modify the coefficients of the mathematical model according to the experimental results.

The structure of the ball mill load parameter detection device of the present invention: as shown in Figures 1 and 2, includes a frame, a ball mill cylinder 1, an electrode, a position sensor 13 for collecting electrode position information, a load cell, and a ball mill cylinder 1 for collecting The rotary encoder 14 of the rotating speed and the computer 20 used for processing and calculating the load parameters, the ball mill cylinder 1 is suspended and fixed on the frame and weighed by the load cell, the bottom of the ball mill cylinder 1 is equipped with electrodes, the position sensor 13 and The rotary encoder 14 is fixed at the bottom of the frame, the signals collected by the position sensor 13 and the rotary encoder 14 are transmitted to the computer 20 through the DI module 16, and the resistance value signal between the electrode and the ball mill cylinder 1 is passed through the resistor A/ The D module 11 , the wireless transmitter 12 and the wireless receiver 19 are transmitted to the computer 20 , and the weight signal of the ball mill cylinder collected by the load cell is transmitted to the computer 20 .

There are at least three electrodes, which are installed at the front end, the middle and the rear end of the bottom of the ball mill cylinder 1, and the connecting line of the installed positions is parallel to the axis of the ball mill cylinder 1. As shown in FIG. 1 , the front electrode 8 , the middle electrode 9 and the rear electrode 10 .

The electrode is bolt-shaped, with a metal wire 24 in the middle and a hard insulating material 22 around it. The electrode passes through the installation hole of the lining plate and is fixed on the lining plate 21 and the cylinder 1 by fastening nuts 23 .

The front hollow shaft 2 and the rear hollow shaft 3 of the ball mill cylinder 1 are respectively fixed on the front base 4 and the rear base 5 of the frame to keep the ball mill cylinder 1 suspended, and the front base 4 is equipped with a front load cell Group 6, 7 groups of rear end load cells are installed on the rear base 5.

The front end load cell group 6 is connected to the front frame weighing transmitter 17, the rear end load cell group 7 is connected to the rear frame weighing transmitter 15, the front frame weighing transmitter 17 and the rear frame The weighing transmitter 15 transmits the amplified and conditioned signal to the computer 20 through the AI module 18 .

The basic detection principle of the present invention is: install electrodes at both ends and the middle of the barrel of the ball mill to measure the resistance between the barrel and each electrode, and analyze the graph of the relationship between the electrode position angle and the electrode resistance value to obtain the ball mill. The detachment angle and contact angle of the load body in the cylinder can be input into the mathematical model to calculate the filling rate of the load body. A rotary encoder is installed on the cylinder to measure the rotation speed of the ball mill cylinder, and the position of the electrode is determined by the rotation speed. Load cells are installed on the bases at both ends of the ball mill to measure the weight of the ball mill cylinder. The weight of the load body (loading capacity) can be obtained by subtracting the empty weight from the total weight. Filling rate, loading capacity, steel ball density , ore density, and pulp concentration are input into the mathematical model for calculating the ball-to-material ratio, and the ball-to-material ratio of the load body can be obtained.

The beneficial effect of the present invention is that it can accurately detect the loading rate parameters of the ball mill in real time, such as the loading rate and the ball-to-material ratio, and is easy to implement and has strong adaptability. It plays an important role in reducing energy consumption. At present, the current method, acoustic method, vibration method, or the combination of these methods used to detect the load parameters of the ball mill cannot simultaneously detect the three parameters of filling rate, loading capacity, and ball-to-material ratio, and can only detect the three parameters. One or two parameters is an indirect detection method, which is easily affected by factors such as ore properties, pulp concentration, power grid fluctuations, and environmental conditions. Not only is the detection accuracy poor, but it cannot be accurately measured during the entire detection process. However, the present invention is not affected by factors such as ore properties, pulp concentration, environmental conditions, etc., belongs to a direct detection method, and can realize accurate detection in the whole detection process.

Description of drawings

Fig. 1 is a structural principle diagram of the detection system of the present invention;

Figure 2 is a schematic diagram of determining the position angle of the motor inside the barrel of the ball mill of the present invention.

In the figure: 1-ball mill barrel, 2-front hollow shaft, 3-rear hollow shaft, 4-front base, 5-rear base, 6-front load cell group, 7-rear end load cell group, 8-front electrode, 9-middle electrode, 10-rear electrode, 11-resistor A/D module, 12-wireless transmitter, 13-position sensor, 14-rotary encoder, 15-rear frame weighing transmitter Device, 16-DI module, 17-front frame weighing transmitter, 18-AI module, 19-wireless receiver, 20-computer, 21-liner, 22-hard insulating material, 23-fastening nut , 24-metal wire, 25-load body.

Detailed ways

The present invention will be further described below in combination with the accompanying drawings and specific embodiments.

Embodiment 1: As shown in Figure 1, this embodiment is used for the detection of grid-type ball mills. The specification of grid-type ball mills is Φ2700×3600. Small transmission gear, motor, electric control) and other main parts. The rotating speed is 50r/min, the ball loading capacity is 45t, the motor power is 355kw, and the power supply is 380VAC. The processed ore is chalcopyrite with a density of 3.1g/cm ³ .

The component selection of this embodiment is as follows: the front load cell group 6 and the rear load cell group 7 are respectively composed of two spoke wheel load cells of the model CYT-2002, and the measurement range of each load cell is 0 -50t, the wiring method is that the two sensors are connected in parallel and then connected to their respective weighing transmitters; the model of the weighing transmitter 15 of the rear base and the weighing transmitter 17 of the front base is DYDS-001, The transmitter is powered by 24 VDC and outputs 4-20mA; the signal of the weighing transmitter is converted by the AI module DTE3216 and input to the computer 20 through the USB port; the signals of the rotary encoder 14 and the position sensor 13 are connected to the DI module 16, and the DI module 16 The model is USB-4751L, connected to the computer 20 by USB; the model of the position sensor 13 is LJ12A3-4-Z, inductive, 24VDC power supply, NPN output; the model of the rotary encoder 14 is E6B2-CW26C, the resolution is 20 pulses/rotation, 24VDC power supply, NPN output; the model of wireless transmitter 12 and wireless receiver 19 is EKI-6351 (1 pair); computer 20 is DELL OptiPlex 3010 desktop; front electrode 8, middle electrode 9, The hard insulating material 22 selected for the back-end electrode 10 is hard ceramics, and the metal wire 24 is metal titanium wire. All components are installed and connected as described above.

The specific steps of the detection method are:

(1) Detect the no-load mass of the ball mill, and then detect the total mass of the ball mill after adding the load body when testing the abrasive, and calculate the loading capacity of the ball mill; the calculation formula for the loading capacity W is: W=K1·(N1-N10)+K2 ·(N2-N20), where K1 is the weight coefficient of the front sensor group (can be calibrated by weight comparison), N1 is the sampling value of the front sensor group, N10 is the sampling value of the front sensor group at no load, and K2 is the back end The weight coefficient of the sensor group (can be calibrated by weight comparison), N2 is the sampling value of the rear sensor group, and N20 is the sampling value of the rear sensor group when it is empty. Through experiments, K ₁ =1.105, N ₁ =54155, N ₁₀ =25120; K ₂ =1.091, N ₂ =53345, N ₂₀ =24620. Then the loading capacity of the ball mill W=55.67t.

(2) Install the electrodes on the barrel of the ball mill. During the operation of the ball mill, measure the resistance between each electrode and the barrel, and the position angle of each electrode. Take the position angle of each electrode as the abscissa and the The resistance value is the ordinate, and the resistance value map of the electrode is respectively established, and the detachment angle θ _A and the contact angle θ _B of the electrode position of the load body are judged according to the change rule of the resistance value, and the detachment angle θ _A and the contact angle θ _B are respectively calculated for each The filling rate of the local load body at the electrode position is calculated by the weighted average method to calculate the overall filling rate of the ball mill;

The calculation formula of cylinder angular velocity ω is:

ω=Kw*P, where Kw is the angular velocity coefficient (can be obtained through calibration), and P is the number of pulses per second. Kw = 0.00385 obtained through experiments, P = 680 measured in real time, then the angular velocity of the ball mill cylinder ω = 2.62/s

The calculation method for judging the position angle of the load body is as follows:

It is obtained through experiments that after the electrode leaves the load body, its resistance value is about R _a =20k; after the electrode enters the load body, its resistance value is R _b =1.1k. Since the electrode rotates with the cylinder of the ball mill, the detachment angle and contact angle of the load body can be estimated based on the comparison between the electrode resistance value and the resistance values of R _a and R _b .

Calculation of the detachment angle and contact angle of the front electrode: when t=0.507s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, the detachment angle θ _a =2.62 x 0.507s=1.33; when t When =0.931s, the resistance value R is smaller than R _b , and this electrode position angle is the contact angle of the load body, and the contact angle θ _b =2.62 x 0.931s=2.44.

Calculation of the detachment angle and contact angle of the middle electrode: When t=0.5s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =2.62 x 0.5s=1.31; when When t=0.92s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =2.62 x 0.92s=2.41.

Calculation of the detachment angle and contact angle of the rear electrode: When t=0.49s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =2.62 x 0.49s=1.29; When t=0.91s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =2.62 x 0.91s=2.39.

Take weights μ ₁ =0.97, μ ₂ =1, μ ₃ =1.03. The experimental measurement K _f =0.97, the calculation method of the filling rate F

F = 1+K _f [μ ₁ (θ _a1 -θ _b1 )+μ ₂ (θ _a2 -θ _b2 )+μ ₃ (θ _a3 -θ _b3 )]/3π

=1+0.98*[0.97*(1.33-2.44)+(1.31-2.41)+1.03*(1.29-2.39)]/3*3.14

=0.644

(3) According to the overall filling rate and loading capacity of the ball mill, combined with the ore density and the pulp density after adding water to the ore, the ball-to-material ratio of the load body is calculated through the ball-to-material ratio mathematical model, which is the load parameter of the ball mill.

According to the mechanism analysis method, the ball-to-material ratio G of the load body is:

In the above formula, d ₁ = 7.8g/cm ³ , d ₂ = 3.1g/cm ³ , the density of water is 1, W=55.67t, C=0.75, V ₀ =17.16 m ³ , F=0.644, K _G =1.03 (calibrated by multiple experiments). According to the above formula, the ball-to-material ratio G=5.55 is calculated

The structure of the ball mill load parameter detection device of this embodiment: as shown in Figures 1 and 2, includes a frame, a ball mill cylinder 1, an electrode, a position sensor 13 for collecting electrode position information, a load cell, and a cylinder for collecting ball mill cylinder 1 Rotary encoder 14 for body speed and computer 20 for processing and calculating load parameters. Ball mill cylinder 1 is suspended and fixed on the frame and weighed by a load cell. Electrodes are installed at the bottom of ball mill cylinder 1. Position sensor 13 and the rotary encoder 14 are fixed at the bottom of the frame, the signals collected by the position sensor 13 and the rotary encoder 14 are transmitted to the computer 20 through the DI module 16, and the resistance value signal collected by the electrode and the ball mill barrel 1 is passed through the resistor A The /D module 11 , the wireless transmitter 12 and the wireless receiver 19 transmit to the computer 20 , and the weight signal of the ball mill cylinder collected by the load cell is transmitted to the computer 20 . There are three electrodes, which are installed at the front end, the middle and the rear end of the bottom of the ball mill barrel 1, and the connecting lines of the installation positions are parallel to the axis of the ball mill barrel 1. As shown in FIG. 1 , the front electrode 8 , the middle electrode 9 and the rear electrode 10 . The electrode is a bolt type, with a metal wire 24 in the middle and a hard insulating material 22 around it. After the electrode passes through the installation hole of the lining plate, it is fixed on the lining plate 21 and the cylinder 1 by the fastening nut 23 . The front hollow shaft 2 and the rear hollow shaft 3 of the ball mill cylinder 1 are respectively fixed on the front base 4 and the rear base 5 of the frame to keep the ball mill cylinder 1 suspended, and the front base 4 is equipped with a front load cell group 6 , 7 groups of rear end load cells are installed on the rear base 5. The front load cell group 6 is connected to the weighing transmitter 17 of the front frame, the rear load cell group 7 is connected to the weighing transmitter 15 of the rear frame, and the weighing transmitter 17 of the front frame and the weighing transmitter of the rear frame are connected. The transmitter 15 transmits the amplified and conditioned signal to the computer 20 through the AI module 18 .

Embodiment 2: As shown in Figure 1, this embodiment detects a mill overflow type ball mill for fine grinding (the specification is Φ1600×4500), the diameter of the cylinder is Φ1600, and the length of the cylinder is 4500mm, which belongs to fine grinding. long structure. It is composed of feeding part, discharging part, rotary part, transmission part (reducer, small transmission gear, motor, electric control) and other main parts. The rotating speed is 60r/min, the ball loading capacity is 30t, the motor power is 250kw, and the power supply is 380VAC. The processed ore has a density of 2.9 g/cm ³ .

The component selection of this embodiment is: the front and rear bases of the ball mill each use a disc-shaped load cell as the weighing part of the front load cell group 6 and the rear load cell group 7, the sensor model is CHBS4, each The measuring range of the load cell is 0-30t; the AI module 18 is a module that integrates signal transmission and AI acquisition, and the model of the AI module is USB7360N, which is connected with the computer 20 through the USB port; the rotary encoder 14 and the position sensor 13 The signal is connected to the DI module 16. The model of the DI module 16 is USB-4751L, which is connected to the computer 20 through the USB interface; the position sensor 13 is an infrared photoelectric type, the model is E3S-DS, 12VDC power supply, PNP output; the rotary encoder 14 The model is E6WB2, the resolution is 40 pulses/rev, 12VDC power supply, PNP output; the front electrode 8 is composed of two electrodes (1,2), the middle electrode 9 is one electrode, and the rear electrode 10 is composed of two electrodes Composed of electrodes (4,5), the hard insulating material 22 of the electrode is made of hard glass fiber reinforced plastic, and the metal wire is titanium wire; a multifunctional wireless sensor 12 integrating signal amplification, data acquisition and wireless transmission and a supporting wireless receiver are used 19. The kit model is JZH-0; the computer 20 is a Lenovo TD4900D desktop; all components are installed and connected according to the method described above.

The specific detection steps include the following:

(1) Detect the no-load mass of the ball mill, and then detect the total mass of the ball mill after adding the load body when detecting the abrasive, and calculate the loading capacity of the ball mill; the calculation formula for the loading capacity W is: W=K ₁ ·(N ₁ -N ₁₀ )+K ₂ ·(N ₂ -N ₂₀ ), where K ₁ is the weight factor of the front sensor group (can be calibrated through experiments), N ₁ is the sampling value of the front sensor group, N ₁₀ is the front sensor group at no load K ₂ is the weight coefficient of the back-end sensor group (can be calibrated by weight comparison), N ₂ is the sampling value of the back-end sensor group, and N ₂₀ is the sampling value of the back-end sensor group at no load. Through experiments, K ₁ =0.506, N ₁ =42220; N ₁₀ =16345, K ₂ =0.502, N ₂ =41476, N ₂₀ =16220. Then the loading capacity of the ball mill is W=25.7t.

(2) Install the electrodes on the barrel of the ball mill. During the operation of the ball mill, measure the resistance between each electrode and the barrel, and the position angle of each electrode. Take the position angle of each electrode as the abscissa and the The resistance value is the ordinate, and the resistance value map of the electrode is respectively established, and the detachment angle θ _A and the contact angle θ _B of the electrode position of the load body are judged according to the change rule of the resistance value, and the detachment angle θ _A and the contact angle θ _B are respectively calculated for each The filling rate of the local load body at the electrode position is calculated by the weighted average method to calculate the overall filling rate of the ball mill;

Calculation of cylinder angular velocity ω:

ω=Kw*P (unit is radian/second)

Kw = 0.0059 obtained through experiments, P = 533 measured in real time, then the angular velocity of the ball mill cylinder ω = 3.14/s

The calculation method for judging the position angle of the load body is as follows:

It is obtained through experiments that after the electrode leaves the load body, its resistance value is about R _a =35.23k; after the electrode enters the load body, its resistance value is R _b =1.356k. Since the electrode rotates with the cylinder of the ball mill, the detachment angle and contact angle of the load body can be estimated based on the comparison between the electrode resistance value and the resistance values of R _a and R _b .

Calculation of the detachment angle and contact angle of the front electrode: When t=0.388s, the resistance value R is greater than R _a , this electrode position angle is the detachment angle of the load body, the detachment angle θ _a =3.14 x 0.388s=1.218; when t =0.833s, the resistance value R is less than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =3.14 x 0.833s=2.617.

Calculation of the detachment angle and contact angle of the middle-end electrode: When t=0.384s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =3.14x 0.384s=1.207; When t=0.826s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =3.14 x 0.826s=2.595.

Calculation of the detachment angle and contact angle of the rear electrode: When t=0.386s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =3.14 x 0.386s=1.212; When t=0.827s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =3.14 x 0.827s=2.598.

Take weights μ ₁ =0.96, μ ₂ =1, μ ₃ =1.04. The experimental measurement K _f =0.98, the calculation method of the filling rate F

F = 1+K _f [μ ₁ (θ _a1 -θ _b1 )+μ ₂ (θ _a2 -θ _b2 )+μ ₃ (θ _a3 -θ _b3 )]/3π

=1+0.88*[0.96*(1.218-2.617)+(1.207-2.595)+0.98*(1.212-2.598)]/3*3.14

=0.62

(3) According to the overall filling rate and loading capacity of the ball mill, combined with the ore density and the pulp density after adding water to the ore, the ball-to-material ratio of the load body is calculated through the ball-to-material ratio mathematical model, which is the load parameter of the ball mill.

According to the mechanism analysis method, the ball-to-material ratio G of the load body is:

In the above formula, d ₁ is the density of steel balls, d ₂ is the density of ore, the density of water is taken as 1, W is the loading capacity of the load body obtained by detection, C is the grinding concentration, and V ₀ is the effective volume of the ball mill cylinder , F is the filling rate of the load body, K _G is the filling rate correction coefficient, and K _G is obtained from multiple experiments. d ₁ = 7.8g/cm ³ , d ₂ = 2.9g/cm ³ , the density of water is 1, W=25.7t, C=0.70, V ₀ =9.04 m ³ , F=0.62, K _G =0.98 (by Calibrated by multiple experiments). According to the above formula, the ball-to-material ratio G=5.03 is calculated

The structure of the ball mill load parameter detection device of this embodiment: as shown in Figures 1 and 2, includes a frame, a ball mill cylinder 1, an electrode, a position sensor 13 for collecting electrode position information, a load cell, and a cylinder for collecting ball mill cylinder 1 Rotary encoder 14 for body speed and computer 20 for processing and calculating load parameters. Ball mill cylinder 1 is suspended and fixed on the frame and weighed by a load cell. Electrodes are installed at the bottom of ball mill cylinder 1. Position sensor 13 and the rotary encoder 14 are fixed at the bottom of the frame, the signals collected by the position sensor 13 and the rotary encoder 14 are transmitted to the computer 20 through the DI module 16, and the resistance value signal collected by the electrode and the ball mill barrel 1 is passed through the resistor A The /D module 11 , the wireless transmitter 12 and the wireless receiver 19 transmit to the computer 20 , and the weight signal of the ball mill cylinder collected by the load cell is transmitted to the computer 20 . There are five electrodes, which are installed at the front, middle and rear ends of the bottom of the ball mill barrel 1, and the connecting lines of the installed positions are parallel to the axis of the ball mill barrel 1. As shown in FIG. 1 , the front electrode 8 , the middle electrode 9 and the rear electrode 10 . The electrode is a bolt type, with a metal wire 24 in the middle and a hard insulating material 22 around it. After the electrode passes through the installation hole of the lining plate, it is fixed on the lining plate 21 and the cylinder 1 by the fastening nut 23 . The front hollow shaft 2 and the rear hollow shaft 3 of the ball mill cylinder 1 are respectively fixed on the front base 4 and the rear base 5 of the frame to keep the ball mill cylinder 1 suspended, and the front base 4 is equipped with a front load cell group 6 , 7 groups of rear end load cells are installed on the rear base 5. The front load cell group 6 is connected to the weighing transmitter 17 of the front frame, the rear load cell group 7 is connected to the weighing transmitter 15 of the rear frame, and the weighing transmitter 17 of the front frame and the weighing transmitter of the rear frame are connected. The transmitter 15 transmits the amplified and conditioned signal to the computer 20 through the AI module 18 .

Embodiment 3: As shown in Figure 1, it is a high-weir type ball mill (with a specification of Φ1800×3000), which uses three small steel balls with different diameters to grind the ore pulp in the beneficiation process. The composition of the component ball mill unit is similar to the above. The rotating speed is 80r/min, the ball loading capacity is 14t, the electrode power is 250kw, and the power supply is 380VAC. The processed ore has a density of 3.0 g/cm ³ .

The component selection of this embodiment is: the front load cell group 6 and the rear load cell group 7 are respectively composed of two cylindrical load cells of the model CYT-201A, and the measurement range of each load cell is 0- 10t, the wiring method is that two sensors are respectively connected in parallel and then connected to the AI module 18; an AI module 18 integrating signal amplification and AI adoption is adopted, the model of the AI module is USB7360N, and the AI module 18 is connected to the computer 20 through USB; The signals of the encoder 14 and the position sensor 13 are connected to the DI module 16. The model of the DI module 16 is USB-4751L, which is connected to the computer 20 by USB; the model of the position sensor 13 is LJ12A3-4-Z, inductive, 24VDC power supply, NPN output; the rotary encoder 14 is connected to the shaft of the reducer of the ball mill, and the angular velocity of the ball mill cylinder can be calculated by calculating the number of pulses of the encoder per unit time. The type of the rotary encoder is E6B2-CW26C, and the resolution is 60 pulses/rotation, 12VDC power supply, NPN output; the model of wireless transmitter 12 and wireless receiver 19 is EKI-6351 (1 pair); computer 20 is Hewlett-Packard P6-1499 desktop; front electrode 8, middle electrode 9 1. The hard insulating material 22 selected for the back-end electrode 10 is hard ceramics, and the metal wire 24 is metal titanium wire. All components are installed and connected as described above.

The formula for calculating the load W is:

W=K ₁ *(N ₁ -N ₁₀ )+K ₂ *(N ₂ -N ₂₀ ),

Through experiments, K ₁ =0.418, N ₁ =38322, N ₁₀ =13023; K ₂ =0.421, N ₂ =36623, N ₂₀ =12635.

Then the loading capacity of the ball mill W=20.61t

The calculation formula of cylinder angular velocity ω is:

ω=Kw*Nr,

Kw = 0.005 obtained through experiments, P = 833 measured in real time, then the angular velocity of the ball mill cylinder ω = 4.18/s

The calculation method for judging the position angle of the load body is as follows:

It is obtained through experiments that after the electrode leaves the load body, its resistance value is about R _a =18k; after the electrode enters the load body, its resistance value is R _b =1.1k. Since the electrode rotates with the cylinder of the ball mill, the detachment angle and contact angle of the load body can be estimated based on the comparison between the electrode resistance value and the resistance values of R _a and R _b .

Calculation of the detachment angle and contact angle of the front electrode: When t=0.333s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, the detachment angle θ _a =4.18 x 0.333s=1.391; when t When =0.625s, the resistance value R is less than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =4.18 x 0.625s=2.611.

Calculation of the detachment angle and contact angle of the middle-end electrode: When t=0.331s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =4.18x 0.331s=1.382; When t=0.622s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =4.18 x 0.622s=2.602.

Calculation of the detachment angle and contact angle of the rear electrode: When t=0.326s, the resistance value R is greater than R _a , the electrode position angle is the detachment angle of the load body, and the detachment angle θ _a =4.18 x 0.326s=1.363; When t=0.619s, the resistance value R is smaller than R _b , the electrode position angle is the contact angle of the load body, and the contact angle θ _b =4.18 x 0.619s=2.588.

Take weights μ ₁ =1, μ ₂ =1, μ ₃ =1. The experimental measurement K _f =0.98, the calculation method of the filling rate F

F = 1+K _f [μ ₁ (θ _a1 -θ _b1 )+μ ₂ (θ _a2 -θ _b2 )+μ ₃ (θ _a3 -θ _b3 )]/3π

=1+0.98*[(1.391-2.611)+( 1.382-2.602)+( 1.363-2.588)]/3*3.14

=0.61

According to the calculation formula of ball material ratio G is

In the above formula, d ₁ = 7.8g/cm ³ , d ₂ = 3.0g/cm ³ , the density of water is 1, W=20.61t, C=0.65, V ₀ =7.63 m ³ , F=0.61, K _G =0.99 (calibrated by multiple experiments). Then calculate the ball-to-material ratio G=5.33 according to the above formula.

The structure of the ball mill load parameter detection device of this embodiment: as shown in Figures 1 and 2, includes a frame, a ball mill cylinder 1, an electrode, a position sensor 13 for collecting electrode position information, a load cell, and a cylinder for collecting ball mill cylinder 1 Rotary encoder 14 for body speed and computer 20 for processing and calculating load parameters. Ball mill cylinder 1 is suspended and fixed on the frame and weighed by a load cell. Electrodes are installed at the bottom of ball mill cylinder 1. Position sensor 13 and the rotary encoder 14 are fixed at the bottom of the frame, the signals collected by the position sensor 13 and the rotary encoder 14 are transmitted to the computer 20 through the DI module 16, and the resistance value signal collected by the electrode and the ball mill barrel 1 is passed through the resistor A The /D module 11 , the wireless transmitter 12 and the wireless receiver 19 transmit to the computer 20 , and the weight signal of the ball mill cylinder collected by the load cell is transmitted to the computer 20 . There are five electrodes, which are installed at the front, middle and rear ends of the bottom of the ball mill barrel 1, and the connecting lines of the installed positions are parallel to the axis of the ball mill barrel 1. As shown in FIG. 1 , the front electrode 8 , the middle electrode 9 and the rear electrode 10 . The electrode is a bolt type, with a metal wire 24 in the middle and a hard insulating material 22 around it. After the electrode passes through the installation hole of the lining plate, it is fixed on the lining plate 21 and the cylinder 1 by the fastening nut 23 . The front hollow shaft 2 and the rear hollow shaft 3 of the ball mill cylinder 1 are respectively fixed on the front base 4 and the rear base 5 of the frame to keep the ball mill cylinder 1 suspended, and the front base 4 is equipped with a front load cell group 6 , 7 groups of rear end load cells are installed on the rear base 5. The front load cell group 6 is connected to the weighing transmitter 17 of the front frame, the rear load cell group 7 is connected to the weighing transmitter 15 of the rear frame, and the weighing transmitter 17 of the front frame and the weighing transmitter of the rear frame are connected. The transmitter 15 transmits the amplified and conditioned signal to the computer 20 through the AI module 18 .

The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Variations.

Claims (10)

1. a ball mill load parameter detection method is characterized in that specifically comprising the steps: (1) Detect the no-load mass of the ball mill, and then detect the total mass of the ball mill after adding the load body when testing the abrasive, and calculate the loading capacity of the ball mill; (2) Install the electrodes on the barrel of the ball mill, measure the resistance between each electrode and the barrel, and the position angle of each electrode during the operation of the ball mill, take the position angle of each electrode as the abscissa, and take the resistance of each electrode as value is the ordinate, establish the resistance value map of the electrode respectively, judge the detachment angle θ _A and contact angle θ _B of the electrode position of the load body according to the change rule of the resistance value, and calculate each electrode according to the detachment angle θ _A and contact angle θ _B The filling rate of the local load body at the position is calculated by the weighted average method to calculate the overall filling rate of the ball mill; (3) According to the overall filling rate and loading capacity of the ball mill, combined with the ore density and the pulp density after adding water to the ore, the ball-to-material ratio of the load body is calculated through the ball-to-material ratio mathematical model, which is the load parameter of the ball mill. 2 . The method for detecting load parameters of a ball mill according to claim 1 , wherein the load body is a mixture of steel balls, ore and water in the barrel of the ball mill. 3 . 3. The method for detecting load parameters of a ball mill according to claim 1, characterized in that: there are at least three electrodes installed on the cylinder of the ball mill, which are installed at different positions of the cylinder. 4. The ball mill load parameter detection method according to claim 1 or 3, characterized in that: the ball mill cylinder has three or five electrodes installed on the front, middle and rear ends of the bottom of the ball mill cylinder. The position connecting line is parallel to the axis of the ball mill cylinder. 5. The ball mill load parameter detection method according to claim 1, characterized in that: the method for measuring the electrode position angle of the ball mill barrel is: installing a rotary encoder on the barrel surface of the ball mill to detect the rotating speed of the ball mill, A position sensor is installed under the barrel of the ball mill. When the electrode passes the position sensor, an electric pulse is generated, thereby determining the zero angle of the electrode. The position angle of the electrode can be calculated by the angular velocity of the barrel and the time when the electrode passes through the zero angle. 6. The ball mill load parameter detection method according to claim 1, characterized in that: the modeling method of the mathematical model of the ball-to-material ratio is: calculate the volume of the internal load body of the ball mill according to the overall filling rate, and then combine the loading capacity, Ore density, steel ball density, ore pulp density, the preliminary mathematical model of the ball-to-material ratio is deduced through the mechanism analysis method, and then the coefficients of the mathematical model are corrected according to the experimental results. 7. A ball mill load parameter detection device according to claim 1, characterized in that the structure includes a frame, a ball mill cylinder (1), electrodes, a position sensor (13) for collecting electrode position information, a load cell, A rotary encoder (14) for collecting the rotational speed of the ball mill cylinder (1) and a computer (20) for processing and calculating load parameters. The ball mill cylinder (1) is suspended and fixed on the frame and weighed by a load cell. The ball mill Electrodes are installed on the bottom of the cylinder (1), the position sensor (13) and the rotary encoder (14) are fixed at the bottom of the frame, and the signals collected by the position sensor (13) and the rotary encoder (14) pass through the DI module ( 16) Transmit to the computer (20), the resistance value signal collected by the electrode and the ball mill cylinder (1) is transmitted to the A computer (20), the weight signal of the ball mill cylinder collected by the load cell is sent to the computer (20). 8. The ball mill load parameter detection device according to claim 7, characterized in that: there are at least three electrodes, which are installed at the front, middle and rear ends of the bottom of the ball mill cylinder (1), and the installation positions are connected with the The axes of the ball mill barrel (1) are parallel. 9. The ball mill load parameter detection device according to claim 7, characterized in that: the front hollow shaft (2) and the rear hollow shaft (3) of the ball mill cylinder (1) are respectively fixed on the front base of the frame (4) and the rear base (5) keep the ball mill barrel (1) suspended, the front load cell group (6) is installed on the front base (4), and the rear scale is installed on the rear base (5). Heavy sensor set (7). 10. The ball mill load parameter detection device according to claim 9, characterized in that: the front-end weighing sensor group (6) is connected to the front frame weighing transmitter (17), and the rear-end weighing sensor group (7 ) to connect the rear base weighing transmitter (15), the front base weighing transmitter (17) and the rear base weighing transmitter (15) to transmit the amplified and conditioned signal to computer (20).

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