Structure of the Stacker Reclaimer

1.1 Stacker Reclaimer Section

The stacker reclaimer mainly consists of a stacking belt conveyor, a steel structure, a stacking rotating mechanism, an upper funnel, auxiliary mechanisms, and support for the conveyor bridge.

The upper part of the stacker reclaimer is equipped with a rotary support (rotating support for the conveyor bridge), with its inner ring fixed to the support, and the top of the support connected to the incoming material bridge through fixed and floating supports.

The lower part of the stacker reclaimer is equipped with a rotary support, with its outer ring having external teeth fixed to the central column using high-strength bolts.

The entire stacker reclaimer is installed on a turntable between two rotary supports, allowing it to rotate around the central column.

The lower turntable of the stacker reclaimer (central platform) is equipped with a vertical planetary reducer, which engages with the outer gear ring of the rotary support through a small gear on the output shaft, achieving the rotation of the stacker reclaimer.

The cantilever of the stacker reclaimer is equipped with a belt conveyor, where materials transported from the bridge's belt conveyor slide down through the upper rotary support and the funnel in the center of the rotating platform onto the stacking belt conveyor, which spreads the materials into the storage bin, completing the stacking operation. 

1.2 Stacking Belt Conveyor

The operation mode of the cantilever belt conveyor is unidirectional, with a stacking output of 800t/h. 800t/h.

The driving device adopts a mechanical external transmission mode with a single-point floating support structure.

The reducer adopts a hollow shaft expansion disc installation form, with lubrication inside the reducer provided by a pump or oil replenishment tank at the shaft end.

The tensioning device uses manual hydraulic tensioning, acting on the drive drum.

The unloading end of the cantilever head is equipped with a redirecting drum and a material blocking plate.

The upper idler spacing is not greater than 1000mm, and the lower idler spacing is not greater than 3000mm. A buffer bed is set at the receiving point, and both the upper and lower belt surfaces are equipped with automatic centering idlers to prevent the belt from running off. The diameter of the idlers throughout is φ133mm, and the normal service life of the idlers is not less than 30,000 hours. The receiving point has a guiding trough to ensure the belt conveyor does not spill materials, with the maximum deviation of the belt not exceeding 50mm. Both the carrying and non-carrying surfaces of the belt should be equipped with cleaning devices.

1.3 Stacking Arm

The stacking arm adopts a truss structure, assembled as a whole in the factory, transported in sections, and welded on-site.

The stacking arm is connected to the central rotating platform and rotates together with the rotating platform.

1.4 Stacking Rotating Mechanism

The stacker reclaimer uses a set of rotary drive arranged on the lower rotating platform, which drives the small gear on the lower part of the turntable through a reducer and an extended shaft.

The small gear meshes with the large gear ring on the rotary bearing, achieving the rotation of the stacker reclaimer.

The rotary drive uses a high-speed ratio planetary reducer, characterized by small size, high speed ratio, and light weight, with variable frequency speed regulation.

2. Reclaimer Section

The reclaimer mainly consists of a steel structure, a scraper reclaimer, a winch mechanism, a reclaiming rotating mechanism, and auxiliary mechanisms.

2.1 Reclaimer Steel Structure

The reclaimer steel structure mainly includes a platform, legs, a tower, tie rods, a counterweight arm, and a counterweight box.

The lower part of the platform is fixed to the central column through a rotary support, connected to the legs at the front end, with the lower part connecting to the drive sprocket group of the scraper reclaimer, and the upper part supporting the tower with a fixed pulley, which is connected to the counterweight arm through tie rods; the rear part of the platform is connected to the counterweight arm. Under the action of the rotary drive, the platform with the scraper reclaimer rotates around the central column.

2.2 Scraper Reclaimer

The scraper reclaiming system is the main component for achieving the reclaiming function, mainly consisting of a drive sprocket group, scraper arm, scraper, chain, tensioning (redirecting) sprocket group, and driving device. The equipment achieves the purpose of scraping materials through the cyclic movement of the scraper chain. The tensioning of the scraper chain is located on the redirecting sprocket at the front end of the scraper arm, using manual hydraulic tensioning. The drive for the scraper chain is fixed on one side of the central column of the scraper arm.

With the continuous operation of the scraper, materials are continuously scraped into the central discharge hopper and transported out via the discharge belt conveyor below the central discharge hopper. 

2.3 Scraper Arm

The scraper arm is a thin-walled cylindrical structure, with sliding tracks for the scraper chain set above and below. The front part supports the tensioning sprocket, while the rear part (near the central column side) is hinged on the lower part of the tower's rotating platform, with the cantilever front end arranged at about 1/3 position for the hinge point of the winch mechanism, allowing the cantilever to change its amplitude as the winch retracts or releases the steel wire rope through a rotating suspension with a pulley group.

2.4 Chain and Scraper

Two conveyor chains are laid in the sliding track of the scraper arm, with scrapers installed on the chains for material scraping. The chains are non-standard large pitch roller chains for conveying. The breaking load of the chains is less than 8 times the rated load. To ensure reliability, each hinge axis of the scraper chain is fixed with a plate-type snap ring.

The roller of the chain runs in a guide groove on a track made of wear-resistant material. Install one scraper for every 4 pitch, the scraper is in a zigzag shape, the flange on the scraper is fixed to the chain with bolts, the scraper is made of steel plate structure, composed of Q345 steel plates, with wear-resistant liners embedded on both side edges and the bottom edge, and scraping teeth embedded on both sides.

2.5 Tensioning sprocket group

The scraper chain tensioning is set on the redirecting sprocket at the front end of the scraper arm, using a manual hydraulic pump station for tensioning. It mainly includes the tail sprocket, sprocket shaft, tension bearing seat with sliding track, hydraulic tensioning device, etc., to ensure the normal tensioning of the chain through the extension and contraction of the hydraulic cylinder.

2.6 Drive sprocket group and drive

The drive part consists of a motor+ hydraulic coupler + 4-stage reduction gearbox, driving the active sprocket group, which is equipped with two drive sprockets. The sprockets are fixed to the scraper arm through bearing seats, located in the gap formed between the scraper arm and the material handling machine's turntable. 

2.7 Hoisting mechanism

The hoisting mechanism consists of an electric hoist, fixed pulley group, movable pulley group, lifting rod, lifting frame, steel wire rope, and other components.

The electric hoist is installed on the platform of the material handling machine, and the fixed pulley group is fixed on the tower of the material handling machine's steel structure, forming an integral part with the tower. The electric hoist is connected to the movable pulley group hinged on the scraper arm frame through the steel wire rope, driving the winding steel wire rope to adjust the inclination angle of the scraper arm frame.

The electric hoist is equipped with a variable frequency motor to achieve fast lifting and slow lowering of the scraper arm. The electric hoist is equipped with an encoder that can memorize the retraction length of the steel wire rope. The drive uses a dual-brake system to ensure that when one brake fails, the other can safely ensure braking.

The steel wire rope adopts a double rope structure.

3. Lubrication system

The machine is equipped with 4 sets of dry oil lubrication systems and 1 set of thin oil lubrication system, providing centralized lubrication to various lubrication points. 4 sets of dry oil lubrication systems:

The top rotary support of the stacker is equipped with 1 independent dry oil lubrication pump station.

The rotary pinion and the middle rotary bearing are equipped with an independent dry oil lubrication pump station.

The material handling machine is equipped with 1 manual centralized dry oil lubrication pump station for the lower rotary support, scraper chain sprocket group bearings, and various hinge points.

The steel wire rope lubrication is equipped with an independent dry oil lubrication pump station.

The scraper chain is equipped with 1 set of thin oil lubrication pump station.

The tensioning sprocket group, steel wire rope, and various pulleys in the hoisting mechanism, as well as open gear drives, require manual lubrication.

4. Walkway

The equipment walkway is mainly divided into two parts: the auxiliary mechanism of the material handling machine and the auxiliary mechanism of the stacker.

The auxiliary mechanism of the material handling machine starts from the protective cover above the circular coal unloading trough, arranging a sloped ladder to the platform in the steel structure of the material handling machine (this layer of platform houses the hoist and main power distribution room).

Above the rotary platform, a layer of platform is arranged based on the tower of the hoisting mechanism (this layer of platform houses the fire protection and sprinkler system, and the driver's cabin).

Based on the tower of the hoisting mechanism, a layer of slow-walk platform is arranged, and above this slow-walk platform, a layer of platform is set leading to the top of the tower, where the upper pulleys of the tower can be maintained.

The ladder of the stacker starts from the upper part of the platform where the cable sliding line is installed and leads to the lower turntable of the stacker.

The lower turntable of the stacker is equipped with the power distribution room and water tank of the stacker, leading up to the cantilever walkway, and then to the upper platform of the stacker.

5. Working principle

The system consists of a stacker, material handling machine, belt conveyor, etc.

The stacker rotates to the pre-stacking warehouse area and begins to stack according to requirements. The material is transported into the warehouse by the incoming belt conveyor on the incoming bridge, falling into the stacker's cantilever belt conveyor through the discharge hopper, and unloaded from the cantilever head. The stacker uses a fixed-point stacking method for stacking operations. First, material is piled at one point, and after reaching the predetermined height, the cantilever rotates, and this process is repeated until the designated stacking area is filled or a stop (shunting) command is received.

The material handling machine performs material retrieval operations on the other side of the material pile. First, it rotates to the designated retrieval area, then lowers the retrieval arm to the material surface and penetrates the material pile to a predetermined depth using the electric hoisting mechanism to retrieve material. While retrieving, the retrieval arm rotates in one direction (e.g., clockwise) at a set speed until all material within the predetermined angle is cleared. After each layer of material is retrieved, the retrieval arm descends at a corresponding angle (i.e., corresponding retrieval depth) according to preset instructions, continuing to retrieve material while the retrieval arm rotates in the opposite direction (e.g., counterclockwise). This process is repeated until all material in the retrieval area is cleared, unless there are special instructions during the retrieval process, otherwise the retrieval arm will be raised to 38.5° to change the retrieval area.

During retrieval, the operator adjusts the material handling machine to the designated material pile area according to the instructions from the central control room (Note: this machine cannot work in the same material pile area as the stacker), using limit devices to control the working area of the material handling machine through the control system.

When the material handling machine adjusts to the material pile area to be picked according to instructions, it limits the rotation position of both ends of the material pile area through a preset angle. The material handling machine will perform reciprocating material picking operations within this position according to a predetermined program. The encoder installed on the electric hoist can accurately control the descending angle of the scraper arm according to the set value, ensuring a constant material picking capacity of the material handling machine. To ensure a constant material picking capacity and a determined picking speed, as the height of the material pile gradually decreases and the picking cross-section continuously increases, the descending angle of the picking arm gradually decreases to fill the designed capacity of the material between the scrapers.

The material handling machine's picking operation speed is adjusted by the frequency conversion of the driving motor, increasing or decreasing the material picking amount by adjusting the picking operation speed.

In special circumstances, the material handling machine can pick materials from a pile that is not fully filled under manual operation.