Roll gap automatic control system for improving work efficiency of roller mill

Abstract

The automatic roll gap control system comprises the roller mill and a PLC (Programmable Logic Controller), a steady flow bin is arranged at the top of the roller mill, a level gage for metering the material quantity in the current bin is arranged in the steady flow bin, a material flow adjusting device with an adjustable opening degree is arranged at an inlet of the roller mill at the bottom of the steady flow bin, and the PLC is connected with the material flow adjusting device. The material flow adjusting device is further provided with an opening degree detecting device in a matched mode and further comprises a frequency converter for controlling an extrusion roller motor of the roller mill, and the PLC is electrically connected with all electric devices. According to the utility model, the working roll gap of the roller mill can be manually set, the rotating speed of the motor is automatically changed according to the change of the upstream incoming material quantity, the roll gap is kept stable at a set value, and a user can enable the roller mill to operate at the optimal power consumption roll gap or the maximum yield roll gap according to the production requirements.

Description

Technical Field

[0001] The utility model relates to the technical field of roller mill equipment, in particular to an automatic roller gap control system for improving the working efficiency of a roller mill. Background Art

[0002] The common operating principle of a roller mill is that two cylindrical squeeze rollers rotate relative to each other, one of which remains stationary, and the other is subjected to a certain pre-pressure by a hydraulic cylinder to bring the two squeeze rollers closer to each other. The material enters the roller gap from between the two squeeze rollers and stretches the roller gap open by a certain distance. During this process, the material is squeezed against each other in the roller gap under the action of hydraulic pressure, generating a large number of microcracks inside it, which plays a role in efficient crushing.

[0003] Based on the above principle analysis, the conditions to ensure the efficient operation of the roller mill are as follows: 1. Pre-pressure suitable for the properties of the material. The properties of ore materials of different varieties and origins vary greatly. When the pre-pressure is small, a dense material layer cannot be formed between the roller gaps, and the crushing effect is poor. When the pre-pressure is too large, the motor current will increase, the material will be over-grinded, which is uneconomical and causes greater wear on the roller surface. Therefore, the pre-pressure is usually pre-selected through experiments on the material, and adjusted according to actual working conditions during operation. Usually, the pre-pressure is fixed when the material properties remain unchanged. 2. Appropriate working roller gap. The hydraulic pressure acts on the material through the extrusion roller. Since the extrusion roller is cylindrical, its effective extrusion area can be calculated according to the formula: pressure angle Therefore, in actual production, the roller gap should be large enough to ensure the extrusion crushing efficiency. However, a roller gap that is too large will cause material leakage in the middle. On the other hand, due to the limited friction of the extrusion roller surface, its ability to bring in materials is also limited. The roller gap cannot be increased blindly. In actual production, the roller mill has an optimal operating roller gap. When operating under this roller gap, the crushing efficiency is high and the power consumption is low. According to empirical data, 0.025 times the diameter of the extrusion roller can generally be selected.

[0004] Roller mills are currently in use, and usually only the hydraulic pressure can be controlled by a hydraulic station. How to make the roller gap run at the optimal roller gap is a big problem. For projects with central control, the central control operator must first comprehensively control the upstream incoming material volume and the downstream sorting volume to make the entire system run in a steady state, and then gradually increase or decrease the throughput of the roller mill to stabilize the running roller gap at the optimal width. For projects where the roller mill is controlled alone, the incoming material volume cannot be controlled, and the roller gap of the roller mill can only change with the upstream feed volume. This is not only inefficient but also easily causes abnormal conditions such as fluctuations in the equipment roller gap and increased vibration. In most crushing and grinding systems, the roller mill, as the core equipment, can consume about 50% of the total system power consumption. Therefore, improving the grinding efficiency of the roller mill can effectively reduce system power consumption and production costs, which has huge economic benefits. Utility Model Content

[0005] The purpose of the present utility model is to provide an automatic roll gap control system for improving the work efficiency of a roller mill, which can artificially set the working roll gap of the roller mill, automatically change the motor speed according to the change of the upstream incoming material quantity, and keep the roll gap stable at the set value. The user can make the roller mill operate at the optimal power consumption roll gap or the maximum output roll gap according to the production needs.

[0006] In order to achieve the above purpose, the technical solution adopted by the present utility model is: an automatic roll gap control system for improving the work efficiency of a roller mill, including a roller mill and a PLC. A steady flow bin is provided at the top of the roller mill. A level gauge for measuring the material quantity in the current bin is provided in the steady flow bin. A material flow regulating device with adjustable opening is provided at the inlet of the steady flow bin at the bottom leading to the roller mill. An opening detection device is also equipped on the material flow regulating device. It also includes a frequency converter for controlling the extrusion roll motor of the roller mill. The PLC is electrically connected to each electrical component.

[0007] Preferably, the material flow regulating device includes two plug plates oppositely arranged at the bottom of the steady flow bin and a worm mechanism for adjusting the opening and closing degree of the two plug plates.

[0008] Preferably, the opening detection device is a displacement detection device arranged between the two plug plates.

[0009] Preferably, the capacity of the steady flow bin is for accommodating the material with a processing quantity in 3 - 5 minutes during the normal operation of the roller mill.

[0010] Preferably, the level gauge is a weighing sensor.

[0011] Preferably, the PLC includes a PID module.

[0012] The beneficial effect of the present utility model is:

[0013] This solution can artificially set the working roll gap of the roller mill, automatically change the motor speed according to the change of the upstream incoming material quantity, and keep the roll gap stable at the set value. The user can make the roller mill operate at the optimal power consumption roll gap or the maximum output roll gap according to the production needs. It enables the roller mill to operate independently and efficiently. For a production line without a central control system, the roller mill does not need to be equipped with a dedicated operator; for a production line with a central control system, it can also reduce the work intensity of the central control operator, enabling them to focus more on the optimization of the entire system process. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0015] Figure 1 This is the overall external schematic diagram of the present utility model.

[0016] Figure 2 This is the overall internal schematic diagram of the present utility model.

[0017] In the figure, 1 is a steady flow bin, 2 is a shutter, 3 is a worm mechanism, and 4 is a roller mill. Specific embodiments

[0018] The present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limited conditions for the implementation of the present utility model. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present utility model can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model.

[0020] At the same time, it should be noted that: unless otherwise defined, the technical terms or scientific terms used herein should have the ordinary meaning understood by those with ordinary skills in the technical field to which the present utility model belongs. The meaning of "a plurality of" used in the specification and claims of the patent application of the present utility model is two or more; the terms "upper", "lower", "left", "right", "front end", "rear end", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model. The change or adjustment of its relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present utility model can be implemented.

[0021] The present utility model will be further described in detail below in conjunction with the embodiments and with reference to the accompanying drawings.

[0022] The present utility model discloses an automatic roll gap control system for improving the working efficiency of a roller mill. As Figure 1 shown, Embodiment 1 includes a roller mill 4 and a PLC. A steady flow bin 1 is provided at the top of the roller mill 4, and the capacity of the steady flow bin 1 is for accommodating the material processed in 3 - 5 minutes during the normal operation of the roller mill 4. A level gauge for measuring the current amount of material in the bin is provided in the steady flow bin 1, and the level gauge is a weighing sensor.

[0023] At the entrance of the roller mill 4 at the bottom of the steady flow bin 1, there is a material flow regulating device with adjustable opening degree, which can adjust the amount of material entering the roll gap of the roller mill 4 by changing the opening degree of its discharge port. The material flow regulating device is also equipped with an opening degree detection device. The material flow regulating device includes two plug plates 2 oppositely arranged at the bottom of the steady flow bin 1 and a worm mechanism 3 for adjusting the opening and closing degree of the two plug plates 2. The opening degree detection device is a displacement detection device arranged between the two plug plates 2.

[0024] This system also includes a frequency converter for controlling the extrusion roll motor of the roller mill 4, which can adjust the rotation speed of the extrusion roll in real time. The PLC includes a PID module. The PLC is electrically connected to each electrical component.

[0025] As Figure 2 shown, the operation of this control system includes the following steps:

[0026] Step 1: The PLC collects the real-time data of the level gauge of the steady flow bin 1, obtains the change trend of the material in the steady flow bin 1 over a period of time, and compares it with the set value;

[0027] Step 2: Since the opening degree of the feeding device determines the outflow speed of the material in the bin, the PID module of the PLC can be called for adjustment: taking the set value of the material quantity in the steady flow bin 1 as the adjustment target, the actual value of the material quantity in the steady flow bin 1 as the input value, and the opening degree of the discharge port of the feeding device as the output value to ensure the constancy of the material quantity in the bin. The parameters such as Kp, Ki, and Kd in the PID module also need to be determined through comprehensive experiments according to the on-site equipment model and material type;

[0028] Step 3: The PLC collects the running roll gap and the rotational speed information of the extrusion roll motor of the current roller mill 4;

[0029] Step 4: Call the PID module of the PLC for adjustment: taking the set value of the roll gap as the adjustment target, the current roll gap value as the input value, and the given value of the rotational speed of the extrusion roll motor as the output value to automatically change the rotational speed of the extrusion roll motor to ensure the constancy of the roll gap; its basic adjustment principle is: when the roller mill 4 is running normally, if the actual roll gap is greater than the set roll gap, increase the rotational speed of the extrusion roll motor. Since the feeding amount per unit time is constant, after the rotational speed increases, the linear speed on the surface of the extrusion roll increases, the material layer in the roll gap becomes thinner, and the roll gap will decrease proportionally; when the actual roll gap is less than the set roll gap, decrease the rotational speed of the extrusion roll motor, and the roll gap will increase proportionally;

[0030] Step 5: When the rotational speed and output power of the extrusion roll motor reach or approach the rated value, it indicates that the roller mill 4 has reached the load limit, and the opening degree of the material flow regulating device cannot be increased anymore. The PLC should give an audible and visual alarm to remind the system operator to reduce the feeding amount to avoid the overflow of the material in the steady flow bin 1.

[0031] When the roll gap is stable, the extrusion roll pressure generally remains constant. However, when there is a leak in the oil cylinder or roll deviation, it is necessary to adjust the pressure on both sides of the extrusion roll to ensure that its working pressure is most suitable for the current material properties.

[0032] It should be noted that the parts not described in detail in the above embodiments are all prior art.

[0033] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An automatic roll gap control system for improving the work efficiency of a roller mill, characterized in that: It includes a roller mill (4) and a PLC. A constant flow bin (1) is provided at the top of the roller mill (4). A level gauge for measuring the amount of material in the current bin is provided in the constant flow bin (1). A material flow regulating device with adjustable opening is provided at the inlet of the constant flow bin (1) leading to the roller mill (4). An opening detection device is also equipped on the material flow regulating device. It further includes a frequency converter for controlling the extrusion roller motor of the roller mill (4). The PLC is electrically connected to each electrical component.

2. The automatic roll gap control system for improving the work efficiency of a roller mill according to claim 1, characterized in that: The material flow regulating device includes two plug plates (2) oppositely arranged at the bottom of the constant flow bin (1) and a worm gear mechanism (3) for adjusting the opening degree of the two plug plates (2).

3. The automatic roll gap control system for improving the work efficiency of a roll mill according to claim 2, characterized in that: The opening detection device is a displacement detection device arranged between the two plug plates (2).

4. The automatic roll gap control system for improving the work efficiency of a roll mill according to claim 1, characterized in that: The capacity of the constant flow bin (1) is for accommodating the material with the processing amount in 3 - 5 minutes during the normal operation of the roller mill (4).

5. The automatic roll gap control system for improving the work efficiency of a roll mill according to claim 1, wherein: The level gauge is a weighing sensor.

6. The automatic roll gap control system for improving the work efficiency of a roller mill according to claim 1, characterized in that: The PLC includes a PID module.

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