Customer Důl Bogatyr, Kazakhstan
Tender deadline 2013
The Study was prepared and realised as a part of tender procedure.
Main parameters of machine
| Rail gauge | 47000 mm |
| Undercarriage wheelbase | 12000 / 9400 mm |
| Diameter of travelling wheels | 630 mm |
| Travelling speed working | 0,02 – 0,3 m/min |
| Travelling speed conveying | 2 – 20 m/min |
| Diameter of drum over buckets | 7230 mm |
| Speed of drum | 3,75 ot/min |
| Number of buckets | 88 |
| Loading belt width | 2000 mm |
| Diameter of driving and tensioning drums | 800 mm |
| Speed of belt | 3,77 m/s |
| Length of conveyor | 51840 mm |
| Diameter of rollers | 159 mm |
| Diameter of supporting rolls | 240 mm |
| Width of stockpile of material to be stored | 44000 mm |
| Length of storage | 845 / 725 m |
General description
Stockyard area
The homogenization stockyard of the Bogatyr Mine (Důl Bogatyr) is divided into two parts with required capacities of 150,000 and 130,000 tons. Length of each area is approximately 800 m. The stockpile in the cross section is 44 mm wide and 15.4 m high for a given material. Material is unpiled with the drum reclaimer with material volume of 5,500 t/h. One drum reclaimer RC-01 or RC-02 is used in each part of the homogenization stockyard. The reclaimer moves on a rail undercarriage along length of the stockyard and makes it possible to unpile material in both longitudinal directions. Both reclaimers have the same design. Material is conveyed from the reclaimer by a 1,800 mm wide drawing-off belt conveyor that is separately dealt with in the tender. This conveyor belt passes through an impact frame for direct loading.
Description of drum reclaimer operation
The drum reclaimer provides a continuous homogenized supply of coal stored on the homogenization stockyard to a follow-up train loader.
Material is unpiled by means of both-side buckets mounted over the total width of the drum uniformly over the total width of the stockyard in the continuous working cycle, even if material is irregularly distributed on the stockyard. A uniform flow of material to buckets is provided by a spreading device that shapes a profile of the material being filled. Material inside the drum slides from buckets to a loading belt that conveys material from the drum to a drawing-off conveyor. When the drum is rotating, the machine slowly moves in the longitudinal direction of the stockyard while the spreading device simultaneously oscillates in the transverse direction.
Working capacity of the machine is measured by a belt scale on the drawing-off conveyors and controlled depending on requirements of the train loader. Material being unpiled can be manually controlled as well.
Description of basic nodes of machine
The drum reclaimer consists of a steel structure carrying the work part – the drum with buckets, whereby material is unpiled. Inside the drum, there is a loading belt from which material is transferred through an impact device to the drawing-off conveyor. The steel structure further supports 2 spreading devices (one per side), 2 cable drums (electric power supply and spray water supply), the machine drive equipment, and the other hydraulic and electric equipment including the operator’s cabin.
Steel structure
The supporting structure consists of a bridge beam to which columns with the drive system are attached. The bridge beam has a three-point mounting, two fixed columns on one side and anchorage to a column with an axial bearing on another side. The drum, on which the loading conveyor system is suspended, is attached to the supporting structure.
Internal spaces of the bridge beam are thermally insulated and air-conditioned, and utilized for the electric switching station, the hydraulic unit and the social background. The bridge beam also houses the air-conditioned cabin, fitted with an operator’s panel with a touch display for selection and display of parameters of all the drives, including alarm messages, a control seat and a camera system monitor. A tower is mounted in the central part of the beam for anchorage of a hoist for lift of spreading devices.
Work drum
The work drum is designed as a single-jacket structure welded from individual cylindrical sections that after having been welded together create a so-called work part of the drum to which both-side buckets are screwed. Before being welded, the individual drum sections are finished on both faces, thereby parallelism of individual contact/weld areas and the resultant cylindrical shape of the drum over the total length are guaranteed. Conical parts are screwed to both ends of the drum, to which travelling tracks and a pin gear of the drum slewing gear are subsequently connected. The inner space of the drum is lined with wear plates.
Travelling tracks and pin gear
The travelling tracks are made from one large-size forging. The required properties – above all hardness – are achieved by subsequent thermal treatment.
The basic pin gear is also made from one piece. In order to achieve high precision, this base is divided into three identical parts only after final machining.
Drum slewing gear
The drum slewing gear drive is solved by means of a pair of drives engaged with the pin gear. Engagement can be adjusted by the drive mounting. Starting is controlled by a soft starter.
Loading Belt
The loading conveyor supporting structure is of a lattice type, with main belts of HEB and HEM profiles, and with tubular web and cross members. Walkways with clearance width of 600 mm are attached to the supporting structure. The structure is suspended on gantries.
Conveying benches with Precismeca arrowheaded rollers and self-adjusting stations for belt centering are mounted on the supporting structure.
The belt drive is ensured by a slip-on gearbox, a Rexnord Omega flexible coupling, a SIBRE drum brake, with indication of lining thickness and brake release. Alternatively, it is possible to use Svendborg hydraulic disc brakes with program control. Drive drum as well as tensioning drum are rubber coated, a drum Martin scraper is used for removal of material from the belt. Starting is controlled by a soft starter.
Impact device
The impact device provides transfer of material from the loading belt to the drawing-off conveyor for the purpose to reduce impacts on the drawing-off belt and its rollers.
The impact device consists of a self-supporting frame, on which Precismeca impact benches and the leading idler sets are suspended. The drawing-off conveyor belt, a correct position of which is adjusted by adjusting rollers, passes through these benches and idler sets. If required, a transfer point to the drawing-off conveyor can alternatively be solved by a mobile charging hopper as well.
Travel system
The drum reclaimer travels on rails on four undercarriages. Each of undercarriages is of a three-beam type, with 5 travelling wheels. The travel drive is realized by means of 8 drive units (2 per undercarriage). The undercarriages are equipped with rail tongs, one per rail, to secure the reclaimer during out-of-operation wind, and with rail cleaner on both sides of the travel.
The drive unit consists of a gearbox with a servomotor controlled by a frequency converter. This servomotor operates in all the required ranges of travel speed, thus it is not necessary to use both independent motors for operation and transport travelling. The drive units are mounted vertically on the external travelling wheels of the undercarriages. Incremental sensors are used for accurate positioning of the machine.
Spreading device
The spreading device provides a transverse oscillating movement, thereby it spreads a surface layer of material and shapes a profile of material on the stockyard to ensure uniform filling of buckets. A spreading device tilting angle can be manually adjusted depending on an actual state of material distribution on the stockyard. The machine is fitted with two spreading devices, one per side of the machine travel direction.
The spreading device structure consists of tubular latticed self-supporting structure to which replaceable spreading bars are screwed. The spreading device travels in the transverse direction by means of four travelling pulleys on a round section. The spreading device can also swing around this section. The transverse oscillating movement is ensured by hydraulic feed, swinging adjustment of the spreading device angle is made possible with a rope lift. Speed of transverse hydraulic feed is adjusted by the control system depending on speed of the drum reclaimer travel.
Lubrication
The automatic lubrication systems are installed on the machine for bearing blocks of the loading belt drums, travelling wheels of the drum slewing gear and the reclaimer travel. The other bearings are lubricated by hand by means of lubrication nipples.
Dedusting system
During the season when the temperature does not fall below zero, the sprinkler is used to reduce dustiness in the place of material transfer from the loading belt to the drawing-off conveyor. To ensure the correct sprinkler function, it is necessary to provide a sufficient water quantity with a necessary pressure in the place of the stockyard centre.
A space of material transfer from the loading belt to the drawing-off conveyor is exhausted via a filtering device and material being exhausted is returned back to the loading belt.
A one-time dust exhausting device is mounted in the drum reclaimer roll. The device consists of the system of suction nozzles and an exhaust duct to which an external exhausting device is connected, if required. If need requires, the operator can change the mode of exhausting by manual control of nozzles and duct.
System of walkways
The system of walkways and stairs ensures that all the points required for the machine operation and maintenance shall be safe and easy to access. The walkway system construction corresponds to the required safety regulations.
Substructures
The substructures functionally connected to the drum reclaimer consist of a rail track (gauge of 47 m), electric supply cables, water supply hoses for the sprinkler system, and end bumpers.
Description of drum reclaimer operation
The drum reclaimer provides continuous homogenized supply of coal stored on the homogenization stockyard to a follow-up train loader.
Material is unpiled by means of both-side buckets mounted over the total width of the drum uniformly over the total width of the stockyard in the continuous working cycle, even if material is irregularly distributed on the stockyard. A uniform flow of material to buckets is provided by a spreading device that shapes a profile of the material being filled. Material inside the drum slides from buckets to a loading belt that conveys material from the drum to a drawing-off conveyor. When the drum is rotating, the machine slowly moves in the longitudinal direction of the stockyard while the spreading device simultaneously oscillates in a transverse direction.
Working capacity of the machine is measured by a belt scale on the drawing-off conveyors and controlled depending on requirements of the train loader. Material being unpiled can be manually controlled as well.
Description of basic nodes of machine
The drum reclaimer consists of a steel structure carrying the work part – the drum with buckets, whereby material is unpiled. Inside the drum, there is a loading belt from which material is transferred through an impact device to the drawing-off conveyor. The steel structure further supports 2 spreading devices (one per side), 2 cable drums (electric power supply and spray water supply), the machine drive equipment, and the other hydraulic and electric equipment including the operator’s cabin.
Steel structure
The supporting structure consists of a bridge beam to which columns with the drive system are connected. The bridge beam has a three-point mounting, two fixed columns on one side and anchorage to a column with an axial bearing on another side. The drum, on which the loading conveyor system is suspended, is connected to the supporting structure.
Internal spaces of the bridge beam are thermally insulated and air-conditioned, and utilized for the electric switching station, the hydraulic unit and the social background. The bridge beam also houses the air-conditioned cabin, fitted with an operator’s panel with a touch display for selection and display of parameters of all the drives, including alarm messages, a control seat and a camera system monitor. A tower is mounted in the central part of the beam for anchorage of a hoist for lift of spreading devices.
