The following is the largest self-propelled machine on the earth: its name is Bagger 288, the world's largest excavator built by the German Krupp Corp in 1978. At first glance, this is a steel giant. It is 46 meters wide, 95 meters high and 240 meters long, with a total weight of 13500 tons. It is called "land carrier". Bagger 288 belongs to bucket wheel excavator (referred to as BWE), mainly used for mining. The wheel bucket excavator, originated in the early European dredger, was improved by British engineer AR. ger stone in 1908 as a chain bucket excavator for iron ore in Corby, England. In 1919, Humboldt company, Germany, developed the world's first bucket wheel excavator, which was used in Lewis mine in Germany in 1925. In 1926, ATG Leipzig obtained the distribution rights of Humboldt company, and in 1938, more than 50 wheel bucket excavators were sold.
Humboldt's bucket wheel excavator is similar to steam shovel, using steam turbine and railway wheel rail chassis. In 1928, Germany Backau-Wolf AG developed the BWE of caterpillar chassis. In 1934, the German O&K company and LMG company co produced the first wheel bucket excavator, after continuous improvement, in 1935 production of 2676 cubic meters per hour model. Two years later, the crawler wheel developed by O&K was successful. The largest wheel in this period belongs to the Rhine brown coal stock company in Rhine, which is the predecessor of the present Rheinbraum. It can dig 3823 cubic meters per hour and the total weight of the machine is 6120 tons. It is made by a company of Cologne in Germany. In 1944, the United States coal power company (now Freeman energy) used the large BWE in W3A coal mine, Illinois to carry out the stripping operation. After the Second World War, the United States Loews Corp began to develop a cross pit type wheel bucket excavator. The 684-WX type wheel made by it made a total of 31 million cubic meters of earth and stone in the construction of the Saint Louis dam in California.
In 1958, Krupp developed the smallest bucket wheel excavator, Krupp 50, which weighs only 52 tons and excavated 210 cubic meters per hour. In the same year, Krupp and O&K developed Bagger 281 giant wheel hopper for German RWE company, which was 220 meters in length, 73 meters high, 7800 tons for the whole machine, and a 103 meter long cantilever. Since 1958, 500 million cubic meters of lignite have been excavated, and fiber optic control and satellite positioning system have been installed after comprehensive renewal. By the 60s of last century, German Krupp signed a cooperation agreement with O&K. The two giants joined hands in the world wheel bucket excavator market and set up a sales and maintenance network. By 70s, Krupp made the giant wheel hopper into its heyday. In 1975, Krupp and O&K co developed Bagger 285, with a total weight of 13500 tons, 200 meters long, 75 meters high, 45 meters wide, 16560 kilowatts of total power, and 200 thousand cubic meters per day. Since then, Krupp has built Bagger in 1976, and built Bagger 288 in 2871978 years. The performance has been further improved and the daily excavation volume has reached 240 thousand cubic meters.
The giant wheel bucket is a special equipment which is generally not mass produced. At present, only 6 units are excavated to 240 thousand cubic meters per day. Among them, Bagger 288 and 289 are almost identical brothers, 290 and 291 are improved slightly by MAN-TAKRAF and KRUPP. After that, the improvement and performance improvement are 292 and 293, which are made by KRUPP and MAN-TAKRAF successively. The two machine performance is basically the same. All of them operate in German coal mines. The Bagger 288 wheel is equipped with 18 buckets, each with a volume of 6.6-8.6 cubic meters. The 4 machines driving the bucket wheel are vertically arranged from top to bottom, with a total power of 3360 kilowatts. The theoretical production capacity is 22000 cubic meters per hour when the 8.6 cubic meter large bucket is assembled to excavate the pine square or coal, and the high strength 6.6 cubic meter thick wall shovel is dug. The theoretical production capacity is 19100 cubic meters per hour when the hard rock or frozen soil is dug, and the 12 tracks are arranged in the first 8 after 4, and the maximum moving speed is 600 meters per hour; only 5 people can operate. The design, manufacture and assembly of the machine took 5 years, and the cost was as high as 100 million dollars.
The ability of Bagger 293 is more striking. It is equipped with 20 8.6 cubic meters of shovel, a total installed capacity of 20 thousand kilowatts, and 3 1680 kilowatt motors with a total power of 5040 kW. The whole machine is 240 meters long, 49 meters wide and 96 meters high, with a total weight of 14210 tons. Even in the face of the most difficult peeling hard rock or permafrost, the actual production capacity can reach 240 thousand cubic meters per day, and its ability to excavate the pine square even reached an unprecedented 300 thousand cubic meters per day. Judging from the main technical parameters of Bagger 293, it has exceeded 288 of the total used in 1978, and has become the real king of excavators.
