A feeding method for a bucket elevator feeding system

Abstract

This invention discloses a feeding method for a bucket elevator feeding system, comprising the following steps: S1, acquiring the current signal of a first motor; S2, comparing the current signal with a preset optimal operating current range; S3, adjusting the feed belt speed and the gate valve opening based on the comparison result. By monitoring the bucket elevator current in real time, the feed rate is dynamically adjusted. When the current exceeds the range, the feed belt speed is adjusted first using a PID algorithm. If the speed adjustment capability is insufficient, the gate valve opening is then adjusted. Overload protection and zero-speed shutdown mechanisms are also included. This achieves adaptive matching between the feeding rate and the elevator load.

Description

Technical Field

[0001] This invention relates to the field of automated control technology for material conveying, and in particular to a feeding method for a bucket elevator feeding system. Background Technology

[0002] In industries such as glass, building materials, chemicals, and grain processing, bucket elevators are suitable for the vertical conveying of granular or powdery raw materials (such as silica sand, limestone, and grains). Taking silica sand conveying in the glass industry as an example, the traditional feeding system architecture usually consists of "feed belt + bucket elevator + soft starter + contactor".

[0003] In actual production, the physical properties of materials (especially silica sand) often fluctuate significantly. For example, due to weather, storage environment, or production process, when the moisture content of silica sand increases from 5% to 12%, the material's viscosity increases and its bulk density rises. At this time, the feed belt, which is still running at a constant rate, will continuously convey excessive amounts of wet material to the bucket elevator, causing a sharp increase in the bucket elevator's load.

[0004] Taking an existing technology that borrows from the PID control principle in the field of automation control as an example, this scheme triggers overload protection in the control system when the operating current of the bucket elevator drive motor exceeds 110% of the rated current (overload threshold), immediately stopping the bucket elevator and simultaneously stopping the feed belt to prevent material blockage. However, this approach has shortcomings in practical applications: it lacks load adaptive capability, resulting in a mismatch between the feed rate of the feed belt and the material characteristics; the bucket elevator's current monitoring only triggers protection, and the system cannot intervene in advance; and there are no coordinated adjustment methods under extreme operating conditions. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the problem that the feeding system cannot adapt to the physical properties of the material.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a feeding method for a bucket elevator feeding system, characterized by comprising the following steps: S1. Acquire the current signal of the first motor; S2. Compare the current signal with the preset optimal operating current range; S3. Adjust the feed belt speed and the gate valve opening based on the comparison results.

[0007] The beneficial effects of this invention are as follows: It provides a feeding method for a bucket elevator feeding system, which collects the current signal of the first motor of the bucket elevator in real time and compares it with the preset optimal operating current range. Based on the comparison result, it coordinates and adjusts the speed of the feed belt and the opening of the gate valve to achieve dynamic response to fluctuations in the physical properties of the material. By constructing a closed-loop system with current as the feedback variable, it can adjust the feed rate and feeding method in the early stage of load increase, avoid load surge and overload shutdown caused by changes in material moisture content and viscosity, and improve the adaptability of the feeding system to materials. Attached Figure Description

[0008] Figure 1 This is a flowchart illustrating a feeding method for a bucket elevator feeding system according to an embodiment of the present invention. Detailed Implementation

[0009] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0010] Before detailing the embodiments of this application, some related concepts will first be explained: In existing technologies, a typical traditional feeding system architecture usually consists of "feed belt + bucket elevator + soft starter + contactor". Among them, the bucket elevator is responsible for conveying materials from the ground to the 34-meter-high material distribution platform. Its drive motor is usually equipped with a soft starter to achieve reduced voltage starting, thereby suppressing the current surge at the moment of startup. The feed belt is responsible for conveying materials (such as silica sand) from the silo to the feed inlet of the bucket elevator. It is directly controlled by the contactor and operates at a fixed power frequency (50Hz), with a constant and non-adjustable speed.

[0011] In actual production processes, the physical properties of materials (especially silica sand, limestone, etc.) often fluctuate significantly. For example, the moisture content of silica sand may dynamically change within the range of 3% to 15% due to weather, storage environment, or production processes. When the moisture content of the material increases (e.g., from 5% to 12%) or particle agglomeration occurs, the material's viscosity increases and its bulk density rises. At this time, the feed belt, which is still running at a constant rate, will continuously deliver excessive amounts of wet material to the bucket elevator, resulting in excessively high material filling rate in the bucket and a sharp increase in load.

[0012] To ensure equipment safety, existing systems are typically equipped with an interlocking protection mechanism based on current detection: when the operating current of the bucket elevator drive motor exceeds 110% of the rated current (overload threshold), the control system triggers overload protection, immediately stops the bucket elevator, and simultaneously stops the feed belt to prevent the blockage accident from escalating.

[0013] However, this mechanism has significant drawbacks in practical applications: once the bucket elevator stops under heavy load, the load torque often far exceeds the direct starting torque of the motor due to the large amount of high-humidity, high-viscosity material accumulated inside the tens-of-meters-high drum. This prevents the equipment from being restarted directly. In this situation, 3-5 maintenance personnel must enter the machine to manually clean the accumulated material layer by layer using a specialized material removal device, a process that takes 4-6 hours. This not only results in a huge waste of labor costs but also causes subsequent production lines to be shut down for extended periods due to material shortages, severely impacting production continuity.

[0014] To at least solve the above problems, please refer to Figure 1 This invention provides a feeding method for a bucket elevator feeding system, comprising the following steps: S1. Acquire the current signal of the first motor; S2. Compare the current signal with the preset optimal operating current range; S3. Adjust the feed belt speed and the gate valve opening based on the comparison results.

[0015] As can be seen from the above description, the beneficial effects of the present invention are as follows: by collecting the current signal of the first motor of the bucket elevator in real time and comparing it with the preset optimal operating current range, the speed of the feed belt and the opening of the gate valve are adjusted in a coordinated manner according to the comparison results, so as to realize the dynamic response to the fluctuation of the physical properties of the material. By constructing a closed-loop system with current as the feedback variable, the feed rate and feeding method can be adjusted in the early stage of load increase, avoiding load surge and overload shutdown caused by changes in material moisture content and viscosity, and improving the adaptability of the feeding system to materials.

[0016] Furthermore, step S3 also includes: S31. When the current signal exceeds the optimal operating current range, the speed of the feed belt is adjusted by a PID algorithm. S32. When it is determined that the speed adjustment capability is insufficient, adjust the opening of the gate valve.

[0017] As described above, the PID algorithm is used first to continuously and precisely adjust the speed of the feed belt to achieve a rapid response to the feed rate. When the speed adjustment reaches its limit and the current signal still cannot return to the optimal range, the opening of the gate valve is adjusted to change the thickness of the material layer on the feed belt, thereby further adjusting the feed rate. By coordinating the adjustment of the feed rate through multiple parameters, the limitations of insufficient adjustment capability of a single actuator are avoided, and the anti-interference capability of the system is improved.

[0018] Furthermore, the PID algorithm adjustment function is disabled during the bucket elevator start-up phase before step S1. At this time, the speed of the feed belt is the first preset speed, and the opening degree of the gate valve is the first preset opening degree. When the bucket elevator reaches its rated speed and maintains it for 10 seconds, the speed of the feed belt is adjusted to the second preset speed, and the opening of the gate valve is adjusted to the second preset opening.

[0019] As can be seen from the above description, by disabling the adjustment function of the PID algorithm during the startup phase and adopting a small opening and low speed feeding mode during the startup phase of the bucket elevator, the startup load can be effectively reduced, avoiding erroneous adjustment of the PID algorithm due to current fluctuations in the bucket elevator during the initial startup phase, and preventing motor failure caused by excessive or insufficient feeding during the startup phase. Once the bucket elevator has been running stably at its rated speed for a preset time, the PID algorithm is activated in the normal operation mode to achieve a smooth transition between the start-up and normal operation processes, thereby ensuring adjustment accuracy.

[0020] Furthermore, it also includes the following steps: S4. Repeat the above steps until the current signal returns to the optimal operating current range. At this time, the speed of the feed belt is the second preset speed and the opening degree of the gate valve is the second preset opening degree.

[0021] As described above, this step enables the system to continuously track the current signal after the material properties change until it returns to the optimal operating range, ensuring that the system can maintain a stable and efficient operating state during the conveying of materials with different batches and different moisture contents.

[0022] Furthermore, when the current signal is higher than the upper limit of the optimal operating current range, the required speed adjustment is calculated using a PID algorithm to reduce the rotational speed of the feed belt.

[0023] As can be seen from the above description, by using the PID algorithm to perform closed-loop regulation of the feed belt, the adjustment amount can be dynamically calculated based on the deviation of the current, so as to reduce the feed amount. By reducing the feeding rate in advance and continuously, the further increase in the load on the bucket elevator is effectively suppressed. The control point is shifted from post-event protection to pre-event intervention, which significantly reduces the probability of material blockage accidents.

[0024] Furthermore, if the feed belt is reduced to the lowest speed and the current signal continues to exceed the upper limit of the optimal operating current range for more than 10 seconds, it is determined that the speed regulation has failed. Obtain the total unloading time of the current batch of materials, adjust the opening of the gate valve according to the deviation of the current signal, and maintain it until the total unloading time ends.

[0025] As described above, when speed regulation fails, a gate valve opening adjustment mechanism based on current deviation and total unloading time is introduced to intervene in extreme working conditions and maintain it until the unloading of this batch is completed, ensuring continuous transportation of the current batch of materials and improving the system's adaptability.

[0026] Furthermore, when the current signal reaches or exceeds a preset overload threshold, the feeding belt is stopped, the gate valve is closed, and an audible and visual alarm is issued. If the current signal does not decrease within 10 seconds, a shutdown protection will be triggered.

[0027] As described above, the tiered approach of stopping material first, then making a judgment, and then stopping the machine provides a buffer recovery opportunity for the system while ensuring equipment safety, reducing unnecessary downtime and improving production continuity.

[0028] Furthermore, the first preset opening degree is 50%; the second preset opening degree is 100%; the first preset speed is 60% of the rated speed; the second preset speed is 100% of the rated speed; and the amplitude of a single adjustment of the gate valve opening degree is less than or equal to 20% of the total opening degree.

[0029] As described above, the startup phase uses 60% speed and 50% opening, which effectively reduces startup impact; during normal operation, it switches to full speed and full opening to ensure rated conveying capacity; the limit design of the gate valve's single adjustment range not exceeding 20% ​​avoids drastic fluctuations in feed rate caused by sudden changes in opening, and enhances the stability of the system adjustment process.

[0030] Furthermore, it also includes the following steps: S5. When a zero-speed signal indicating that the bucket elevator has stopped is detected, the feed belt is stopped.

[0031] As described above, when the bucket elevator stops due to malfunction, jamming, or other reasons, the feed belt is immediately stopped, effectively preventing serious material blockage or equipment damage caused by the continuous accumulation of material inside the bucket elevator.

[0032] Specifically, in one embodiment of the present invention, a bucket elevator feeding system includes: Bucket elevator; The first motor is used to drive the bucket elevator; A current detection unit is located in the power supply circuit of the first motor and is used to collect the current signal of the first motor in real time. The feeding device includes a gate valve and a feeding belt; a second motor is used to adjust the feeding rate of the feeding belt; An adjustment component for adjusting the opening degree of the gate valve; The controller is connected to the current detection unit, the second motor and the adjustment component respectively. The controller controls the feeding rate of the feed belt and the opening degree of the gate valve according to the current signal collected by the current detection unit.

[0033] As described above, the current detection unit, second motor, gate valve, and regulating components enable real-time monitoring of the bucket elevator's load status and coordinated adjustment with the feeding device's feed rate, resulting in rapid response and rich adjustment dimensions. The gate valve opening adjustment works in synergy with the feed belt speed adjustment. In extreme conditions, even when the feed belt speed is at its minimum and the feed rate cannot be effectively controlled, further reducing the gate valve opening reduces the feed rate from the source, overcoming the weakness of single speed regulation methods that are prone to failure under high-moisture and high-viscosity material conditions. The connection between the controller and the regulating components forms a closed-loop opening control, ensuring adjustment accuracy and effectively avoiding feed rate fluctuations caused by opening deviations. This enhances the system's adaptability to fluctuations in material physical properties and its stability under complex conditions.

[0034] Specifically, in this embodiment, the bucket elevator is used to transport granular or powdered materials vertically. A first motor drives the bucket elevator. The current detection unit is a current transmitter, located in the power supply circuit of the first motor, used to collect the current signal of the first motor in real time and transmit the current signal (4-20mA analog quantity) to the controller.

[0035] The feeding device, located at the feed inlet of the bucket elevator, includes a feed belt and a gate valve. The feed belt is used to transport material from the silo to the feed inlet of the bucket elevator; the gate valve is a V-type gate valve, located between the feed inlet of the feed belt and the discharge outlet of the silo, used to adjust the feed rate of the silo, thereby controlling the total amount of material entering the bucket elevator.

[0036] The second motor is used to drive the feed belt, and its speed is adjusted by a frequency converter (speed range 0-50Hz). The control signal terminal of the frequency converter is connected to the analog output module of the controller.

[0037] The regulating assembly includes a cylinder and a solenoid directional valve. One end of the gate valve is connected to the cylinder, which in turn is connected to the solenoid directional valve. The solenoid directional valve is connected to the analog output module of the controller. When the frequency converter cannot maintain the current signal of the bucket elevator within the optimal current range (set according to the rated power of the bucket elevator, such as 80%-90% of the rated current), the controller controls the solenoid directional valve by outputting an analog signal, which in turn controls the cylinder, thereby achieving continuous adjustment of the gate valve opening. The opening adjustment range is 0% to 100%. The magnitude of a single adjustment of the gate valve opening is less than or equal to 20% of the total opening.

[0038] The controller is a programmable logic controller (PLC), which is connected to the current detection unit, frequency converter, and solenoid directional valve respectively. It is used to execute the steps in the feeding method according to the current signal fed back by the current detection unit.

[0039] The specific feeding method in this embodiment is as follows: Start-up phase: Before starting the bucket elevator, the controller disables the PID algorithm adjustment function and sets the feed belt to a first preset speed. The gate valve opening is also adjusted to a first preset opening to avoid excessive material accumulation during the initial startup phase. This first preset speed corresponds to a frequency of 30Hz (i.e., 60% of the rated frequency of 50Hz) from the frequency converter output, and the first preset opening is set to 50% of the maximum opening of the gate valve.

[0040] After the soft start is complete (the bucket elevator reaches its rated speed and maintains it for 10 seconds), the controller activates the PID algorithm adjustment function and enters the normal adjustment mode, causing the feed belt to run at the second preset speed, and the gate valve opening to be adjusted to the second preset opening to avoid excessive material accumulation during the initial start-up. This first preset speed corresponds to the frequency output of the frequency converter being 50Hz (i.e., 100% of the rated frequency of 50Hz), and the first preset opening is set to 100% of the maximum opening of the gate valve.

[0041] Normal operation phase: When the moisture content of the material (silica sand in this embodiment) is between 3% and 7%, the controller detects that the current signal of the bucket elevator is within the optimal current range, and then controls the frequency converter to make the feed belt run at 50Hz (rated speed). At the same time, the V-gate valve remains at 100% opening to maximize feeding efficiency.

[0042] When the material moisture content is between 8% and 15%, and material accumulation causes the bucket elevator's current signal to exceed the upper limit of the optimal current range, the controller prioritizes activating the PID algorithm to adjust the speed of the feed belt. If the speed adjustment causes the bucket elevator's current signal to fall back to the optimal current range, the feed belt maintains its current frequency, and the V-gate valve remains 100% open.

[0043] Extreme operating condition stage: If the feed belt has already reduced to the lowest speed (e.g., 30Hz) within the speed adjustment range, and the current signal of the bucket elevator still exceeds the upper limit of the optimal current range for more than 10 seconds, the controller determines that the speed adjustment has failed and performs coordinated opening adjustment. At this time, the controller controls the solenoid directional valve by outputting an analog signal, which in turn controls the cylinder to reduce the gate valve opening from 100% to a preset opening (e.g., 60%-70%, dynamically set according to the current deviation). Simultaneously, the controller calls upon the material unloading time parameter library and, based on the total unloading time for each vehicle (e.g., 15 minutes), maintains the gate valve opening until the end of the total unloading time. This ensures stable feed rate throughout the entire unloading cycle and avoids frequent adjustments. After unloading is completed, the gate valve opening returns to 100%, and the system continues to monitor the bucket elevator current changes. If the current signal falls back to the optimal current range, the opening coordination adjustment exits, and the system enters normal operation. If it still exceeds the optimal current range, the extreme operating condition phase is repeated, and the opening is further reduced (e.g., 50%, but the single adjustment range does not exceed 20% to avoid a sudden drop in feed rate).

[0044] It is worth noting that in this embodiment, the parameter settings during the startup phase effectively reduce the feed rate at startup, avoiding motor overcurrent or bucket elevator jamming caused by excessive startup load. This is especially suitable for suppressing startup impact when conveying high-humidity, high-viscosity silica sand.

[0045] In addition, a limit protection phase is also provided: When the operating current of the bucket elevator drive motor continuously rises due to extreme operating conditions (such as material agglomeration, high humidity and adhesion), approaching the preset overload threshold (set to 110% of the rated current in this embodiment), the controller triggers the secondary protection program. The first level of protection is executed immediately: the controller reduces the speed of the feed belt to 0Hz through the frequency converter, stopping the feeding; at the same time, the control adjustment component closes the V-type gate valve to 0% opening, cutting off the material supply at the source; and an audible and visual alarm is issued to remind the operator to pay attention to the on-site operating conditions.

[0046] If the current signal does not drop to a safe range within 10 seconds after the first-level protection measures are implemented, it indicates that a serious blockage or mechanical jam has occurred inside the bucket elevator. In this case, the controller will trigger the second-level protection, immediately cut off the power supply to the first motor, and stop the bucket elevator from running, effectively preventing the motor from being damaged due to prolonged overload.

[0047] In addition, in this embodiment, the bucket elevator is equipped with a zero-speed detection switch to monitor the operating status of the bucket elevator in real time. When the controller detects a zero-speed signal (i.e., the bucket elevator stops abnormally), it will immediately and automatically stop the operation of the feed belt regardless of the current level, to prevent material from continuously accumulating inside the elevator and avoid further escalation of the blockage accident.

[0048] In summary, the feeding method of the bucket elevator feeding system of the present invention has the following beneficial effects: 1. A closed-loop regulation mechanism with current as the feedback variable was constructed, which enables the feed rate to match the dynamic changes in the physical properties of the material in real time. This effectively avoids the sudden increase in load caused by fluctuations in the moisture content and viscosity of the material, significantly reduces the risk of overload shutdown of the bucket elevator, and improves production continuity and work efficiency. 2. By disabling the adjustment function of the PID algorithm during the startup phase, a small opening and low speed feeding mode is adopted during the startup phase of the bucket elevator. This can effectively reduce the startup load, avoid PID algorithm misadjustment due to current fluctuations in the bucket elevator during the initial startup phase, and prevent motor failure caused by excessive or insufficient feeding during the startup phase. 3. After the bucket elevator has been running stably at the rated speed for a preset time, switch to normal operation mode and enable the PID algorithm adjustment function to achieve a smooth transition between the start-up process and the normal operation process, thereby ensuring adjustment accuracy; 4. When speed regulation fails, a gate valve opening adjustment mechanism based on current deviation and total unloading time is introduced to intervene in extreme working conditions and maintain it until the unloading of this batch is completed, ensuring continuous transportation of the current batch of materials and improving the system's adaptability.

[0049] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A feeding method for a bucket elevator feeding system, characterized in that, Including the following steps: S1. Acquire the current signal of the first motor; S2. Compare the current signal with the preset optimal operating current range; S3. Adjust the feed belt speed and the gate valve opening based on the comparison results.

2. The feeding method of a bucket elevator feeding system according to claim 1, characterized in that, S3 further includes the following steps: S31. When the current signal exceeds the optimal operating current range, the speed of the feed belt is adjusted by a PID algorithm. S32. When it is determined that the speed adjustment capability is insufficient, adjust the opening of the gate valve.

3. The feeding method of a bucket elevator feeding system according to claim 1, characterized in that, During the bucket elevator startup phase before step S1, the adjustment function of the PID algorithm is disabled. At this time, the speed of the feed belt is the first preset speed, and the opening degree of the gate valve is the first preset opening degree. When the bucket elevator reaches its rated speed and maintains it for 10 seconds, the speed of the feed belt is adjusted to the second preset speed, and the opening of the gate valve is adjusted to the second preset opening.

4. The feeding method of a bucket elevator feeding system according to claim 1, characterized in that, It also includes the following steps: S4. Repeat the above steps until the current signal returns to the optimal operating current range. At this time, the speed of the feed belt is the second preset speed and the opening degree of the gate valve is the second preset opening degree.

5. The feeding method of a bucket elevator feeding system according to claim 2, characterized in that, When the current signal is higher than the upper limit of the optimal operating current range, the required speed adjustment is calculated by the PID algorithm to reduce the rotational speed of the feed belt.

6. The feeding method of a bucket elevator feeding system according to claim 5, characterized in that, When the feed belt drops to the lowest speed and the current signal continues to exceed the upper limit of the optimal operating current range for more than 10 seconds, the speed regulation is determined to be in failure. Obtain the total unloading time of the current batch of materials, adjust the opening of the gate valve according to the deviation of the current signal, and maintain it until the total unloading time ends.

7. The feeding method of a bucket elevator feeding system according to claim 1, characterized in that, When the current signal reaches or exceeds the preset overload threshold, the feed belt is stopped, the gate valve is closed, and an audible and visual alarm is issued. If the current signal does not decrease within 10 seconds, a shutdown protection will be triggered.

8. The feeding method of a bucket elevator feeding system according to claim 3, characterized in that, The first preset opening is 50%; the second preset opening is 100%; the first preset speed is 60% of the rated speed; the second preset speed is 100% of the rated speed; and the amplitude of a single adjustment of the gate valve opening is less than or equal to 20% of the total opening.

9. The feeding method of a bucket elevator feeding system according to claim 1, characterized in that, It also includes the following steps: S5. When a zero-speed signal indicating that the bucket elevator has stopped is detected, the feed belt is stopped.

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