The bridge-type roller reclaimer is used in the mining industry, a device that achieves efficient mixing of bulk materials. This article introduces the BN5500 bridge-type roller reclaimer model custom-designed by NOEN company of Czech Republic for a certain mining area. The main parameters of the equipment are as follows:

1. Stockyard Area

The homogenization yard is divided into two parts, with required capacities of 150,000 tons and 130,000 tons, respectively. The length of each area is approximately 800 meters. For specific materials, the cross-sectional width of the material pile is 44 meters, and the height is 15.4 meters. Unloading is performed using a per hour 5500-ton capacity roller reclaimer. One roller reclaimer ( RC-01 or RC-02) is used in each part of the homogenization yard. The reclaimer moves along the track frame in the direction of the length of the yard and can unload in two longitudinal directions. The designs of the two reclaimers are identical. The material is transported away from the reclaimer via an 1800 mm wide discharge conveyor, which is specified separately in the tender. This conveyor passes through a buffer frame for direct loading.

  

2. Roller Reclaimer Operation Description        

The roller reclaimer continuously and uniformly supplies the coal stored in the homogenization yard to the subsequent train loading machine.

In a continuous work cycle, uniform unloading across the entire width of the yard is achieved through double-sided buckets installed across the entire width of the roller, even if the material is unevenly distributed in the yard. A material distribution device shapes the material into a filled profile, thus providing a uniform material flow to the buckets. The material inside the roller slides from the buckets onto the loading conveyor, which transports the material from the roller to the discharge conveyor. As the roller rotates, the machine slowly moves along the longitudinal direction of the yard, while the material distribution device simultaneously swings in the transverse direction.

The working capacity of the equipment is measured by a belt scale on the discharge conveyor and controlled according to the requirements of the train loading machine. The unloading material can also be manually controlled.

3. Description of Basic Equipment Components         

The roller reclaimer consists of a steel structure that carries the working components (roller with buckets), and unloading is done through the roller. Inside the roller is a loading conveyor, and the material is transferred from the loading conveyor to the discharge conveyor via a buffer device. The steel structure also supports two material distribution devices (one on each side), two cable reels (for power supply and water spraying), the equipment drive unit, and other hydraulic and electrical equipment, including the operator's cabin.

3.1 Steel Structure

The support structure consists of a bridge girder, with columns for the drive system connected to the girder. The bridge girder is installed using a three-point mounting method, with two fixed columns on one side and anchored to a column with an axial bearing on the other side. The roller, on which the loading conveyor system is suspended, is connected to the support structure.

3.2 Working Roller

The working roller is designed as a single-cylinder structure ，welded from individual cylindrical sections. These sections are welded together to form the so-called working part of the roller, to which the double-sided buckets are bolted. Before welding, the two end faces of each roller section are machined to ensure the parallelism of the various contact /welding areas and the cylindrical shape over the entire length of the roller. Conical parts are bolted to both ends of the roller, and then the walking track and the roller rotating gear pinions are connected to the conical parts. The interior of the roller is lined with wear-resistant plates.

3.3 Walking Track and Pinions       

The walking track is made from a large forging. The required properties, especially hardness, are achieved through subsequent heat treatment. The basic pinions are also integrally formed. To achieve high precision, this base is only divided into three identical parts after final machining.    

3.4 Roller Rotating Gear

The drive of the roller rotating gear is achieved through a pair of drive units that mesh with the pinions. The meshing can be adjusted by the installation of the drive unit. Starting is controlled by a soft starter.

3.5 Loading Conveyor

The support structure of the loading conveyor is a lattice structure, with the main beams using HEB and HEM sections, with tubular webs and beams. A walkway with a net width of 600 mm is installed on the support structure. This structure is suspended from the gantry.

The support structure is equipped with a conveyor worktable with Precismeca arrow-shaped rollers and an automatic self-aligning device for belt centering.

The belt drive is ensured by a sleeve gearbox, a Rexnord Omega flexible coupling, and a SIBRE roller brake with lining thickness indication and brake release indication. Alternatively, a Svendborg hydraulic disc brake with program control can also be used. Both the drive roller and the tension roller are rubber-coated, and Martin roller scrapers are used to remove material from the belt. Starting is controlled by a soft starter.

 

3.6 Buffer Device           

The buffer device is used to transfer material from the loading conveyor to the discharge conveyor, with the aim of reducing the impact on the discharge belt and its rollers.          

The buffer device consists of a self-supporting frame, on which a Precismeca buffer worktable and a set of guide rollers are suspended. The discharge conveyor belt passes through these worktables and roller sets, and its correct position is adjusted by adjusting the rollers. If necessary, the transfer point of the discharge conveyor can also be replaced by a movable loading hopper.

3.7 Walking System

The cylindrical reclaimer travels on the track via four bogies. Each bogie is a three-beam type, equipped with five traveling wheels. The traveling drive is achieved through eight drive units (two per bogie). The bogie is equipped with track clamps (one per track) to secure the reclaimer when the equipment is shut down and there is wind, and track cleaners are equipped on both sides of the traveling direction.

The drive unit consists of a gearbox with a servo motor, and the servo motor is controlled by a frequency converter. This servo motor can operate within all required traveling speed ranges, thus eliminating the need for two separate motors for traveling and transport traveling operations. The drive unit is vertically mounted on the outer traveling wheels of the bogie. Incremental sensors are used to achieve precise positioning of the equipment.

3.8 Material Spreading Device

The material spreading device provides lateral swing motion, thereby spreading the surface layer of the material and forming the material profile on the stockpile to ensure uniform bucket filling. The inclination angle of the spreading device can be manually adjusted according to the actual situation of material distribution on the stockpile. The equipment is equipped with two spreading devices, one on each side in the direction of equipment travel.          

The structure of the spreading device consists of a tubular truss self-supporting structure, and replaceable spreading rods are bolted to this structure. The spreading device moves laterally on a circular cross-section track via four traveling rollers. The spreading device can also swing around this cross-section. The lateral swing motion is ensured by a hydraulic feed device, and the angle of the spreading device can be adjusted by a rope lifting device. The speed of the lateral hydraulic feed is adjusted by the control system according to the traveling speed of the cylindrical reclaimer.     

3.9 Lubrication System

An automatic lubrication system is installed on the equipment to lubricate the bearing housings of the loading belt rollers, the traveling wheels of the roller rotating gears, and the traveling parts of the reclaimer. Other bearings are manually lubricated through grease nipples.         

3.10 Dust Removal System

In seasons with temperatures not lower than zero degrees Celsius, a sprinkler system is used to reduce the dust concentration of the material transferred from the loading belt to the discharge conveyor. To ensure the normal operation of the sprinkler system, sufficient water volume and necessary pressure must be provided at the center of the stockpile.          

The area where the material is transferred from the loading belt to the discharge conveyor is de-dusted by a filter device, and the extracted material is returned to the loading belt.          

A disposable dust removal device is installed on the roller of the cylindrical reclaimer. This device consists of a suction nozzle system and an exhaust pipe, and an external dust removal device can be connected to the exhaust pipe if needed. If necessary, the operator can manually control the suction nozzle and exhaust pipe to change the dust removal mode.     

 

3.11 Walkway System

The walkway and staircase system ensures that all locations required for equipment operation and maintenance are safe and easily accessible. The structure of the walkway system complies with the required safety regulations.

3.12 Ancillary Structures

Ancillary structures related to the function of the cylindrical reclaimer include a track (gauge 47 meters), power cables, water supply hoses for the sprinkler system, and end buffers.