Introduction to Bucket Wheel Stacker Reclaimers:

A bucket wheel stacker reclaimer is a type of high-efficiency loading and unloading machinery used in large dry bulk material yards. It can both stack and reclaim materials and has continuous conveying capabilities. It consists of a conveyor belt arm that can tilt and swing horizontally, a bucket wheel at the front end, a frame, and a running mechanism. The belt can run bi-directionally. When reclaiming, the bucket wheel collects material and sends it out via the conveyor arm; when stacking, the material transported by the main conveyor is sent to the yard via the conveyor arm.

A rail-mounted loading and unloading machine that uses a bucket wheel for continuous reclaiming and a conveyor belt for continuous stacking. It is specialized machinery for bulk material storage yards, evolved from bucket wheel excavators, and can form a mechanized material handling system with unloading (ship/truck) machines, conveyor belts, and loading (ship/truck) machines. , Production capacity can reach 1 tens of thousands of tons per hour. Bucket wheel stacker reclaimers have highly regular operations, making automation easy. Control methods include manual, semi-automatic, and automatic.

Bucket wheel stackers are classified into boom type and gantry type according to their structure. Some equipment only has one function, either reclaiming or stacking, and are called bucket wheel reclaimers or stackers.

Bucket wheel stackers are suitable for material storage yards in large and medium-sized thermal power plants, docks, mines, metallurgy, chemical industry, and large water conservancy projects. in bulk materials of stacking and reclaiming.

Classification of Bucket Wheel Stacker Reclaimers: Bucket wheel stackers are classified into boom type and gantry type according to their structure.

1. Structural Composition of Boom Type Bucket Wheel Stacker Reclaimers.

Boom type bucket wheel stacker reclaimer manufactured by Harbin Heavy Industry Bulk Material Equipment Co., Ltd.

Boom Type Bucket Wheel Stacker Reclaimers Consist of bucket wheel mechanism, upper metal structure, cantilever conveyor belt, walking mechanism, tilting mechanism, slewing mechanism, middle hopper, auxiliary structure, tail car, counterweight, dust removal system, lubrication system, high and low voltage electrical room, driver's room, and electrical system, etc.

The bucket wheel mechanism consists of buckets, wheel body, arc baffle, drive mechanism, and chute, etc. The bucket wheel mechanism retrieves bulk materials through excavation and lifting and places them onto the cantilever conveyor belt; it is the reclaiming working mechanism.

The upper steel structure consists of the front boom, gate post, front tie rod, rear tie rod, and counterweight frame, etc., and is the main steel structure of the bucket wheel stacker reclaimer.

The cantilever conveyor belt consists of a drive roller, a reversing roller, rollers, and a belt drive mechanism, etc. The conveyor belt can move in both forward and reverse directions to achieve stacking and reclaiming functions.

The walking mechanism consists of a balance beam, a truck frame, wheel sets, and a truck drive mechanism. The walking speed can be steplessly adjusted. Low speed is used during stacking and reclaiming operations, and high speed is used during shunting to save time and improve work efficiency.

The tilting mechanism consists of a hydraulic cylinder and a hydraulic station, etc. The overall swing of the upper steel structure is driven by the tilting mechanism to achieve stacking and reclaiming at different parts of the bucket wheel machine.

The slewing mechanism consists of an upper slewing ring, a lower slewing ring, a slewing bearing, and a slewing drive mechanism. to achieve conveyor belt ± 110 ° range stacking and reclaiming.

The tail car structure is divided into single tail car, return tail car, double tail car, and full-function tail car. The single tail car can achieve one-way stacking and one-way reclaiming; the return tail car can achieve one-way stacking and one-way reclaiming; the double tail car can achieve one-way stacking and two-way reclaiming; the full-function tail car can achieve two-way stacking and two-way reclaiming.

Boom Type Bucket Wheel Stacker Reclaimers CAD General Plan

2. Gantry type bucket wheel machines are divided into gantry bucket wheel stackers and gantry bucket wheel reclaimers.

Gantry Bucket Wheel Stacker Reclaimers

Gantry bucket wheel stacker reclaimer manufactured by Harbin Heavy Industry Bulk Material Equipment Co., Ltd.

Gantry Bucket Wheel Stacker Reclaimers: has a gantry-shaped metal frame and a liftable movable beam, the movable beam has two fixed conveyor belts and a movable, bi-directional stacking conveyor belt. A tail car that moves with the gantry is installed on the yard conveyor belt line on one side of the gantry. No gantry bucket mechanism through circular tracks, support wheels, and stop wheels mechanism, installed on a trolley that can move along the lifting movable beam When stacking, the material is transferred to the stacking conveyor belt via the yard conveyor belt and the tail car, and finally discharged to the yard. Through 。 the movement and the operation of the stacking conveyor belt on it, the material forms a pile of a certain shape. When reclaiming, the transversely moving trolley and its rotating bucket wheel continuously reclaim material, and the material is unloaded to movable beam the conveyor belt in the unloading area, and finally transferred to the yard conveyor belt for transport. Through movable beam the lifting and running of the gantry, the pile can be completely reclaimed. movable beam 的升降和门架的运行，可将料堆取尽。

Gantry Bucket Wheel Reclaimer

The main structural difference between the gantry bucket wheel reclaimer and the gantry bucket wheel stacker reclaimer is : It does not have a tall gantry , The bridge is fixed and non-lifting, and is located at a lower position ； There is no stacking belt conveyor and tail car; there is a material rake fixed on the trolley in front of the bucket wheel 。 When the trolley runs, it drives the material rake to move along the end face of the material pile, causing the loose material on it to slide down so that the bucket wheel can pick up the material. The material rake can also mix the materials stacked in layers by the stacker according to different materials when sliding down, so it is often called a bridge-type bucket wheel mixing and material-taking machine.

Components of the bucket wheel stacking and reclaiming mechanism:

The boom-type bucket wheel stacking and reclaiming machine consists of a bucket wheel mechanism, a slewing mechanism, a belt conveyor, a tail car, and a pitching and running mechanism.

① Bucket wheel mechanism: It is the working mechanism for material taking, including the bucket wheel and its driving device. Bucket wheels are divided into unformatted, semi-formatted and formatted types. 3 type. The buckets of the unformatted bucket wheel have no bucket bottom. In the non-discharging area, the loose material in the bucket is blocked by a circular baffle fixed on the boom, and the loose material slides on the circular baffle. There is no circular baffle in the discharging area, but a fixed inclined chute. When the bucket rotates with the wheel body to the discharging area, the material in the bucket slides down to the belt conveyor under its own weight through the inclined chute. Its discharging interval is large, so the bucket wheel speed is high, which can improve the operation capacity and can unload more sticky materials. The structure of the semi-formatted bucket wheel is similar to that of the unformatted one, except that the bucket wall is extended to the center of the bucket wheel for a section, increasing the distance between the circular baffle and the wheel body to reduce the possibility of material jamming between the circular baffle and the wheel body. Each bucket of the formatted bucket wheel has a sector-shaped inclined chute as the bucket bottom, but there is a fixed side baffle in the non-discharging area. When the bucket rotates with the wheel body to a certain height, ,  the loose material in the bucket begins to slide towards the center of the bucket wheel along the sector-shaped inclined chute , After the bucket reaches the discharging area, due to the absence of side baffles, the loose material slides onto the belt conveyor through the inclined chute and the discharge plate. The formatted bucket wheel discharges slowly and requires a larger bucket wheel diameter, but it will not cause material jamming, and is suitable for hard materials. Among the three types of bucket wheels, the unformatted type is the most widely used. The bucket wheel has two transmission methods: mechanical and hydraulic, and generally does not require speed regulation.

② Slewing mechanism: It consists of a slewing bearing and a driving device , Used to make the boom rotate left and right. To ensure that the bucket can be filled at any position of the boom , The slewing speed is required to be 0.01 ~ 0.2 turn / per minute, and automatic stepless regulation according to a certain law is realized within the range. Most use DC motors or hydraulic drives.

③ Boom belt conveyor: Used for conveying materials. During stacking and reclaiming operations, the conveyor belt needs to run in both forward and reverse directions.

④ Tail car: A mechanism that connects the yard belt conveyor with the bucket wheel stacking and reclaiming machine. The conveyor belt of the yard belt conveyor passes over two rollers on the tail car frame, forming a S shape , so that the material can be transferred from the yard belt conveyor to the bucket wheel stacking and reclaiming machine during stacking.

⑤ Pitching mechanism and running mechanism: They are similar to the corresponding mechanisms in gantry cranes.

Operating modes of bucket wheel stacking and reclaiming machines:

It has two operating modes: stacking and reclaiming. Stacking is the process of transporting loose materials from the belt conveyor to the belt conveyor on the boom via the tail car, and then discharging them from the front end of the boom to the yard. Through the operation of the whole machine, the rotation and pitching of the boom can make the material pile form a neat trapezoidal cross-section. Reclaiming is continuously achieved through the rotation of the boom and the bucket wheel. The material is discharged to the reverse-running boom belt conveyor via the discharge plate, and then discharged to the yard belt conveyor via the hopper below the center of the machine. Through the operation of the whole machine, the rotation and pitching of the boom can enable the bucket wheel to reclaim all the materials in the storage pile.

Automation development of bucket wheel stacking and reclaiming machines:

With the economic development and transformation of China, the cost of labor is gradually increasing, and ordinary technical workers will be in short supply. The bucket wheel stacking and reclaiming machine belongs to heavy-duty work, and at least three shifts are required for continuous operation. Therefore, the management mode of manually controlling the operation of the equipment will become increasingly difficult, and it is imperative to improve the automation level of equipment operation. The unmanned management mode of bucket wheel machines is the inevitable trend of future development and has broad development prospects.

At present, the stacking of most bucket wheel machines in China is completed by the bucket wheel machine driver manually operating the bucket wheel machine on site. In the reclaiming process, the reclaiming amount of the bucket wheel machine is judged by the naked eye, and the flow rate is controlled by controlling the start and stop of the bucket wheel machine slewing arm.

Due to the long operation time of the bucket wheel machine and frequent operations during stacking and reclaiming, the labor intensity of the operators is very high, and they are prone to fatigue, which leads to unstable operation efficiency for a long time. High-intensity manual operation intensity is easy to cause visual fatigue, causing mechanical impact, increasing the risk of safe operation, and even affecting the service life of the equipment. At the same time, the belt scale is affected by the bucket wheel machine itself and cannot accurately measure. However, due to many on-site interference factors, the material flow cannot be combined with the control of the bucket wheel machine during the stacking process, which is easy to cause irregular stacking of the material pile and reduce the amount of material stored in the yard. In the reclaiming process, manual judgment and manual adjustment based on experience lead to unstable reclaiming amount, which reduces the reclaiming efficiency and is also prone to overload, affecting the safe operation of the system. The start and stop of the bucket wheel machine trolley traveling and the slewing of the boom side process, it is easy to produce equipment vibration, and the speed is reduced to reduce vibration, which affects the operation efficiency of the bucket wheel machine. The original image monitoring coverage of the bucket wheel machine is small, and there are blind spots. During the stacking operation, it cannot effectively monitor in all directions and all weather, especially at night or in foggy weather, which is not conducive to safe operation and affects the efficiency of the reclaiming process.

For the above bucket wheel machine existing Issues, Harbin Heavy Industry Loose Material Equipment Co., Ltd. Proposes the use of Bucket wheel reclaimer addressing system, safety anti-collision system, 3D modeling system, data transmission system, flow monitoring system, communication system, remote operation center and central control station To perform constant flow material control and intelligent sequential control, ultimately achieving a fully automatic unmanned bucket wheel reclaimer control system.

Although using A fully automatic unmanned control system ， But also retains the on-site manual operation method of the bucket wheel stacker reclaimer. On this basis, remote manual, semi-automatic, and fully automatic operation modes are realized. Remote manual operation includes remote hard manual operation and remote soft manual operation;   Semi-automatic operation includes automatic positioning of the coal pile, during the stacking / Material handling methods and boundary identification, etc. Aspects require manual selection and confirmation; fully automatic operation specifically refers to the operation where, during operation, only the staff needs to confirm the initial settings such as coal stacking and coal loading schemes, issue operation commands, and achieve unmanned intervention in the equipment operation process, which can control the bar-shaped stacking and reclaiming to automatically complete the walking, rotation, and pitching of the stacking and reclaiming mechanism, keeping the stacker reclaimer working within the rated output range, and the working process covers automatic stacking and automatic reclaiming. Realizing remote hard manual operation involves installing a remote operation terminal for the bucket wheel reclaimer in the coal conveying control room. Realizing smooth switching between manual and automatic operation of stacking and reclaiming in the cab, improving operational efficiency and system safety.

By using a laser scanner to perform cross-sectional scanning above the cantilever belt, real-time detection of the instantaneous coal flow rate is achieved. The reclaiming amount is obtained through cross-sectional calculation, achieving fully automatic constant flow reclaiming. At the same time, a level 1 overload alarm and level 2 overload interlock tripping function are set for the instantaneous coal flow rate. When the instantaneous coal flow rate reaches the rated value of the stacker reclaimer, the system automatically alarms and automatically adjusts the reclaiming flow rate to ensure normal equipment operation. For values exceeding the rated value by a certain range, the system implements interlock tripping.

The positioning system of the bucket wheel reclaimer includes the main moving mechanism ——Main machine travel, cantilever pitching, cantilever rotation. Using high-precision multi-turn absolute value encoder ， Position correction equipment is also installed. For the main machine travel, an RFID system is used to correct the unified on-site communication protocol, and the encoder data is input to PLC Real-time detection of the change in the amplitude angle and the collected data is input to PLC For processing, facilitating control and observation of the stacker reclaimer's operation in the control room.

The pitching angle is measured using a pitching instrument, the travel and rotation use Gray code positioning, and other positioning uses encoders to obtain the displacement information of the bucket wheel reclaimer, achieving positioning tracking.

Fully automatic stacking strategy: For automatic stacking, the main machine travel fixed-point stacking or cantilever rotation fixed-point stacking method is selected. The stacking height is detected in real-time using a material height detection device. The system uses “Full-layer rotary stacking method”, the thickness of each layer of stacking does not exceed 1 Meters, the top is flat, and the lowest point of the bucket edge is less than 1 Meters from the coal dropping point, reducing losses and environmental pollution. The stacking height and width can be set independently, and the system automatically adjusts the rotation speed and backward stepping, without manual intervention throughout the process. For coal piles entering the coal yard, a coal pile ledger is generated.

Fully automatic reclaiming strategy: After the bucket wheel stacker reclaimer automatically starts the relevant equipment (cantilever belt, bucket wheel) according to the process flow, it automatically starts reclaiming (the reclaiming amount can be set as needed). The control system automatically controls the reclaiming stepping and cantilever rotation until the reclaiming process is completed. The system uses “Layered and segmented (area) reclaiming method”, the bucket wheel cantilever rotates horizontally close to 90 ° to The outer edge of the coal pile, keeping the coal yard flat and the shape standard. The bucket wheel reclaimer control system automatically adjusts according to the set reclaiming amount, maintaining constant flow reclaiming, without manual intervention throughout the process. According to the coal quantity in the current area, a coal reclaiming ledger is generated.

Real-time coal inventory: During the operation of the bucket wheel reclaimer (including manual and automatic modes), real-time coal inventory of the coal pile is performed. The coal pile data is updated in real-time on the remote operator station of the bucket wheel reclaimer. At the same time, coal pile data (graphics) can be manually deleted and mistakenly deleted data can be restored with one click on the remote operator station of the bucket wheel reclaimer. Historical playback of coal pile data (graphics) is performed on the graphics server. The bucket wheel stacker reclaimer automation system needs to use the coal yard measurement system data as the modeling basis to achieve real-time guidance of the bucket wheel stacker reclaimer automation model guidance.

The unmanned bucket wheel reclaimer automation system has a built-in diagnostic function. When a measurement point fails, malfunctions, or the system experiences a major failure, it can issue an alarm, and in addition to being prominently displayed on the bucket wheel reclaimer monitoring screen, it can also issue an audio-visual alarm on the remote operation terminal. When the bucket wheel reclaimer operating parameters exceed the set values, it can self-protect, so that the remote monitoring personnel of the bucket wheel reclaimer can promptly discover and intervene. Without affecting safety, it automatically stops running and alarms.

The unmanned system can perform video monitoring of key parts of the bucket wheel reclaimer. Video cameras are installed on the bucket wheel reclaimer, and the video information is transmitted to the control room via an industrial television network. The operator performs real-time video monitoring of the on-site operation scene. It can monitor the tail car position, tail car belt; cantilever belt and ground belt; tower top position; stacking and reclaiming boom condition; cable reel position, observing the cable reel; rotary position, observing the boom condition during stacking and reclaiming; under the cantilever belt, observing the bucket wheel; low-voltage switch room, observing the operation of electrical equipment.

Combining traditional bucket wheel stacker reclaimer technology with innovative information technology to achieve bucket wheel Fully automatic unmanned control of the stacker reclaimer System new equipment 。This system Through Laser scanning technology to obtain real-time information about the on-site yard, the position of the bucket wheel reclaimer, and the real-time status of the cantilever pitching angle and rotation angle. Through a specific algorithm, the bucket wheel reclaimer is automatically controlled to perform the specified tasks. Through this system, automatic stacking and reclaiming of loose materials in the yard are realized, strengthening the management of loose materials in the plant and improving operational efficiency.

Common faults of bucket wheel stackers:

Bucket wheel stackers and reclaimers are prone to wear and tear during operation. Traditional solutions involve welding or electroplating followed by machining, but both have drawbacks: the high temperature of welding creates residual stress that cannot be completely eliminated, easily causing material damage and leading to bending or breakage of components; while electroplating is limited by coating thickness and is prone to peeling. Furthermore, both methods use metal to repair metal, failing to change “ hard-on-hard ” mating relationship. Under the combined action of various forces, re-wear will still occur. Modern Western countries mostly use high-polymer composite materials for repair, with the American Belzona ( 1st line ) technology being widely used. It has superior adhesion and excellent compressive strength, allowing for repair without disassembly or machining. There is no welding stress, and the repair thickness is not limited. The material's inherent flexibility, absent in metals, absorbs impact and vibration, preventing re-wear and significantly extending the service life of equipment components, saving companies significant downtime. It is gradually replacing traditional methods in the repair of bucket wheel stacker and reclaimer failures in China.

Development of Bucket Wheel Stackers and Reclaimers in China:

The development of bucket wheel stackers and reclaimers in China has generally gone through three stages. In the 1960s and 1970s, China began designing small bucket wheel stackers and reclaimers, with typical models such as 3025 and 8030, having output capacities of 300t/h and 800t/h, and turning radii of 25m and 30m respectively. The 1980s and 1990s marked the second stage of development. Newly built bulk material yards in steel mills and power plants gradually adopted large bucket wheel stackers and reclaimers for stacking, reclaiming, and transporting bulk materials. For example, Shanghai Baosteel and Qinhuangdao port yards used bucket wheel stackers and reclaimers with output capacities of 2000t/h and turning radii of 40m. Due to limitations in domestic conditions at the time, the construction of these material yard conveying equipment was often collaborative manufacturing or complete machine imports, with even entire bulk material conveying systems being imported from abroad. After 2000, the development of bucket wheel stackers and reclaimers in China entered a new stage. To date, domestic manufacturers have the design and manufacturing capabilities for a series of bucket wheel stackers and reclaimers with production capacities of 300～6000t/h and turning radii of 25～60m. In this stage, foreign manufacturers still occupy a certain share, but domestic manufacturers have mastered considerable technology and production capacity, and have occupied the mainstream position in the domestic market with their service and price advantages, and are gradually entering the international market.

Note: Port Equipment Network Port Machinery Academy Bucket Wheel Stacker and Reclaimer column is sponsored exclusively by Harbin Heavy Industry Loose Material Equipment Co., Ltd. 獨家贊助。

Reprinted from Port Equipment Network 。