A Derrick Crane is docking equipment installed on vessels or dockside. Derrick crane consists of derrick and hoisting mechanism. There are 3 or 4 steel wires connecting the derrick and hoisting mechanism, which controls hoisting mast goes up and down. A separate steel wire sling runs under the hoisting mast with a hook as the hoisting mechanism.
Features of Weihua Derrick Crane:
1. There are 4 driving system for the hoisting mechanism, 2 driving system for luffing mechanism.
2. The whole derrick crane chassis adopt basin support on concrete foundation, which can effectively ease the horizontal and vertical deformation of the derrick crane.
3. Multi-layer winding line reel drum. Hoisting winding drum wrapped with 4 layers of wire rope, and luffing drum is wrapped with 5 layers of wire rope.
4. Complete frequency control, half load lifting speed is 2 times faster than the full load lifting speed.
5. Inverter, encoder and electronic control system to ensure the 4 hoisting motors keep synchronous working.
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Derrick Crane Derrick Crane,Fixed Derrick Crane,Fixed Dock Crane,Self-Climb Crane Henan Weihua Heavy Machinery Co., Ltd. , https://www.weihuacranefactory.com
It was China that first discovered and used zinc in the world. In the 10th to 11th centuries, China was the first country to produce zinc on a large scale. In the last year of the Ming Dynasty, Song Yingxing’s book Tiangong Kaiwu has the earliest record of zinc smelting technology in the world. The production process is very simple. The calamine (ie, the zinc ore) is filled in a clay pot and sealed in a cone. The gap between the tank and the tank is filled with wood carbon, and the can is broken to obtain the extracted. Metal zinc ingots. In addition, Wang Chain (1888-1966), a pioneer in the study of chemical history and analytical chemistry in China, analyzed the ancient moneys of Tang, Song, Ming and Qing in 1956 and found that the Song Dynasty’s Shaosheng money contained high levels of zinc and proposed China. Zinc began with the correct scientific conclusions during the Jiaqing period of the Ming Dynasty. The actual application of zinc may be earlier than the age of the book.
The name zinc comes from the Latin Zincum, which means “white thin layer†or “white depositâ€. Its chemical symbol Zn is also derived from this, and its English name is Zinc.
A brief history of zinc discovery
Zinc is also one of the elements that humans know about their compounds since time immemorial. Zinc ores and copper alloy melt was prepared - brass, as early as the ancient people used. However, the acquisition of metallic zinc is much later than that of copper, iron , tin and lead . It is generally believed that this is due to the fact that when the carbon and zinc ore are co-heated, the temperature is as high as 1000 C or more, and the boiling point of the metallic zinc is 906 C. That is, it becomes a vapor state, and it is not easy to be noticed by ancient people when it is lost with smoke. Only when people master the method of condensing gas, it is possible to obtain elemental zinc.