BIURO PROJEKTOWO-TECHNICZNE BUCKET WHEEL EXCAVATOR KWK-910

Transcription

1 BIURO PROJEKTOWO-TECHNICZNE BUCKET WHEEL EXCAVATOR KWK-910

2 Mechanizmy SAFETY AND COMFORT The main operator's cabin is the control center of the machine. Comfortable operator's work conditions facilitate taking advantages of a whole range of the excavator's options and faultless interpretations of hundreds of displayed data. A comprehensive communication system ensures an access to all crucial points of the machine and enables its safe operation.

3 GENESIS Deposit exploitation conditions - the basis for the project assumptions for KWK-910 excavator. After many years of exploitation, Turoszów deposits are still evaluated to possess almost 500 mln tons of industrial resources of lignite but their further exploitation will be largely hindered by deteriorating geological and mining conditions. The deposits of the first lignite deck and overlay to be exploited are characterized by a highly complicated and irregular geological struc ture (irregular depositing, faults, multidirectional sloping, fractures and discontinuities) as well as highly differentiated digging characteristics (from considerably easily diggable to hard diggable layers, stone insertions and interlayers of cohesive rocks). The excavators currently operated in Turów opencast mine are not adapted to the efficient exploitation in such differentiated deposits, which results in their high mortality and, as a consequence, low actual capacity as compared to their theoretical parameters. The mentioned exploitation conditions of hard diggable formations in the overlay of the first lignite deck made it necessary to design an excavator: with resistance suitable for the required digging parameters at the required capacity and with machine elements and the bearing structure durable enough, with technological parameters such as the range of lowering and slewing of the extension arms, manoeuvrability, traction parameters, foundation pressure, etc. which ensure its proper functionality on highly complicated, short and sloppy exploitation frontlines. The above mentioned requirements were specified in details in the project assumptions for the Contract of the main contractor of a single-unit wheel excavator of KWK-910 type for the exploitation of hard diggable formations signed on by and between the Management Board of BOT KWB Turów S.A. and SKW Biuro Projektowo-Techniczne Sapkowski, Kanczewski, Wocka sp.j. in Zgorzelec. That was the decision to construct the first in Poland excavator for the exploitation of hard diggable formations; an excavator designed especially for deposit conditions of BOT KWB Turów S.A.

4 GENERAL CHARACTERISTIC While designing an excavator meant especially for limited to 1.1. deposit conditions of Turów opencast mine the configuration An exceptional advantage of the excavator is the of the machine, working ranges, manoeuvrability and other solution of the right choice of the bucket wheel drive gearbox technological parameters were assumed as well as the and durable joints for the gearbox and the bucket wheel shaft. digging forces and the resistance of elements, systems and the The excavator of max. digging force 47 T with specific cutting bearing structure of the machine to the expected dynamic forces of k L up to 200 kn/m is adapted to digging hard loads. The vast experience of the mining exploitation and diggable fractions (interlayers) or selecting non-diggable maintenance services, acquired during the exploitation of the layers. The excavator is equipped with a gearbox designed existing machines was also taken into account. especially for the exploitation requirements of the lowest Considering the requirements as for the technical parameters operational levels of Turow mine. and the need to ensure a high exploitation reliability of the The most important mechanisms of the excavator excavator the main machine systems were designed as a (gearboxes, bearing nodes) are equipped with built-in special construction, i.e.: temperature and vibro-acoustic sensors in order to be able to A detailed analysis and the selection of digging apply online diagnostics. This enables the exploitation of the parameters was carried out, which resulted in obtaining their machine according to the technical conditions strategy, which high values as well as considerable digging process largely facilitates early emergency threat detection and smoothness (owing to the 1000 kw drive, with 16 buckets at proper planning of maintenance and its scope, at the same the wheel of 10 m diameter). time eliminating the early preventive exchange of costly In order to improve the durability of the machine elements. elements, mainly in the digging system, the traditional The bearing structure of the excavator is methods of their dimensioning in relation to nominal values characterized with high rigidity of all systems with flexible and then allowing high overloads with coefficients of values of suspension of the digging extension arm (in order to rapidly were abandoned. In the offered excavator high cut out dynamic and impact loads), which ensures high nominal values are assumed and the overload coefficient is reliability and longevity as for the fatigue durability.

5 GENERAL CHARACTERISTIC All the relative movements of the machine systems are measured; the excavator is adapted to the application of the manoeuvring movements' automatics, full monitoring and remote control. It is also entirely secured against collisions, overloads, range excess, etc, with movement and force measures, terminal joints, sensors and probes. As the machine is designed for the operation in hard diggable deposits, which is connected with the existence of impact loads of high values, the excavator is equipped with a system of tensometric sensors for the measurement of tensions in the crucial points of the structure. Such a system, constantly gathering data connected with the loads history enables up to date evaluation of the bearing structure durability and in future will help to identify threats within the fatigue durability. An optimal selection of the superstructure and undercarriage systems rigidness ensures advantageous work conditions of the ball bearing. A special ball bearing of 9000 mm diameter is designed, with two-rows of 150 mm diameter balls, of low pressure and high resistance to horizontal loads. The described advantages ensure high exploitation durability of the turntable with increased loads during the operation at the slopes of 1:20 + 1:25 and at the nominal lateral digging force 24 T. The localization of the operator's cabin extension arm at the tower ensures the insulation from vibrations generated during the digging process. The casing of the bucket wheel in the lower part of the digging extension arm, apart from technological advantages ensures good visibility of the digging area for each position of the bucket wheel. The inner transportation system ensures the collection 3 of the output with max. capacity of 4400 m /h for each work conditions. Summarizing, we are convinced that the domestic production of opencast mining basic machines is enriched with an important model of a new generation excavator for the exploitation of hard diggable formations. With this excavator we offer a modern, highly automated machine with a visualization of the digging processes, control and diagnostics, equipped with an industrial TV and diagnostic, warning, fire safety and other installations. The modern design, a method of digging, rotation, crawler drive system and transportation system are obvious advantages of our machine as compared to similar and much more expensive imported machines of this type. Solutions ensuring the comfort of work are worth mentioning as well as work safety and work conditions (air-conditioning, controllers, low level of noise, vibrations, etc.), which makes this machine user and environment friendly.

6 SPECIFIC FEATURES OF THE MACHINE A crawler drive mechanism is equipped with the wellproven fixture of the movement wheels of long life type, facilitating the lubricating system. The control with an inverter ensures a smooth regulation of the drive speed and enables driving at various speeds of particular crawlers, which facilitates turning. Three-point support for the carriage is based on ball-andsocket joints with modern bronze lining of high durability. The steering with a hydraulic cylinder provides a turning radius R= 25 m, unique for 6-crawler machines, and secures the support system and undercarriage structure against the loads resulting from the interaction of passive forces from the foundation. The slewing mechanism consists of four drive systems with hydraulic drives cooperating with a toothed ring of the module m=27. Flexible support for the moment levers and securing devices in the hydraulic system buffer the effects of side impact loads from the digging organ. The system of the bucket wheel boom lowering is equipped with a modern hoisting winch with a double drive controlled with an inverter. Such a solution ensures a fluent speed and boom lowering regulation with an option of changing the direction of lowering without pawling of the hoisting winch brakes.

7 SPECIFIC FEATURES OF THE MACHINE The lowering of the discharge boom is implemented with a hydraulic cylinder. This is a simple and easy solution which ensures a wide range of lowering and which is suitable for the implementation in a relatively light suspended pipe structure for the discharge boom. The digging system with 2 x 500 kw drives is an effect of planning to reach the unitary cutting force of 200 kn/m. A modern planetary gear of 1000 kw drives the bucket wheel through an easily disassembled tooth coupling and a shield fixed to the wheel with spring screws. A single layer wheel with a self-cleaning chute is equipped with characteristic spokes ensuring the transfer of the large side digging loads. The digging system is suspended with joints to the extension structure through a moment lever with a joint. The overload device of an extremely short operational time and high precision of the overload settings is a proof of the highest technical level in the field of excavator security against the effects of impact loads. 16 buckets are placed at the perimeter of the bucket wheel of 10m diameter, which favourably decreases the dynamics of the digging process and ensures the size reduction of the output. The intentionally shaped geometry of the bucket corners made of special alloy is a result of many years of experience and tests carried in the conditions of hard diggable deposits.

8 SPECIFIC FEATURES OF THE MACHINE The double-belt system results in only one central hopper in the slewing axis of the superstructure. It is easily accessible both from the top and from the region of the belt chute of the loading conveyor, which considerably facilitates the exploitation as compared to single system machines with an intermediate conveyor. The excavator is equipped with belt conveyors with the belt of B=1800 mm, exceeding the requirements of the theoretical capacity of the digging system. This facilitates the transfer of local pile-ups of the output and keeping the machine clean. The removal of stones from the belt is provided by the stone remover - a device already tested in Turow opencast mine. The removal of stones can be controlled from the main operator's cabin basing on the industrial television display or from a special cabin of the belt I operator. The connection of the pylon with the slewing platform, which is a crucial point of the machine structure in C system, is designed and performed with due diligence. The articulated joints of the structure are shaped so as to ensure maximum resistance to side dynamic loads. It is applicable to the counterbalance extension arm, the mast and the connecting strands.

9 MANUFACTURING AND ASSEMBLY The elaboration of the technologically sophisticated production of the support joints with a layer bronze lining for basic machines is an innovation in the production of such construction nodes. The assembly of the heaviest elements of the structure required the usage of special cranes of 100 t capacity at 40 m range. The operation of the assembly of main elements of the carriage the tower, the counterbalance extension arm, the mast with strands and the bucket wheel boom entirely assembled at the construction site was performed with the use of cranes of nominal capacity of 500t and 350t in the shortest possible time of two weeks.

10 EXPLOITATION Capacity testing in a semi-hard overburden proved high efficiency of the digging unit. No resonance effects in steel structure were observed during exploitation and transport of the excavator. Relative low dynamic stresses in steel structure were registered during digging semi-hard material. Buckets of new design proved its efficiency in semi-hard material. Self-sharpening bucket corners worked four times longer then bucket teeth used so far reaching nominal capacity of the excavator with relative low power consumption.

11 TECHNOLOGICAL DATA Theoretical capacity - maximal m /h 3 Bucket capacity - nominal 910 dm Bucket wheel diameter 10 m Number of buckets 16 pcs Cutting speed 2,176 m/s Number of discharges 66,5 1/min Bucket wheel drive power 1000 kw Nominal cutting force 419 kn Maximal cutting force 461 kn Specific cutting force - maximal 200 kn/m Digging heighth 15,0 m Digging depth -2,0 m Digging radius 30,0 m Discharge radius 34,0 m Slewing drive power 160 kw Slew angle of superstructure ±180 Slewing speed (in bucket wheel axle) 8-30 m/min Hoisting speed of bucket wheel boom 5,6 m/min Feeding conveyor - belt width 1800 mm - belt speed 3,35 m/s - drive power 320 kw Discharge conveyor - belt width 1800 mm - belt speed 3,35 m/s - drive power 200 kw Discharge boom slew angle ±105 Travel speed 0-8,8 m/min Minimal turning radius 25 m Number of crawlers 3 x 2 szt. Crawler plate width 2800 mm Caterpillar chain pitch 520 mm Crawler drive power 6 x 55 kw Permissible ground inclination: longitudinal transverse - exploitation 1:20 1:25 - transport 1:15 1:33 Average ground pressure 116 kpa Total weight 1605 t

12 KOPARKA KWK-910 SKW Biuro Projektowo-Techniczne Sapkowski, Kanczewski, Wocka sp. z o.o. Armii Krajowej 51A Zgorzelec skw@skw.pl Tekst: Projekt graficzny: Opracowanie: Wacław Sapkowski Jarosław Kowalczyk Marek Kowalczyk