Special Crane

Special cranes are needed to perform the process steps, such as container handling, placement of goods in the warehouse of the cell, to transport the molten metal, explosives, etc. The special bridge-type cranes include bridge cranes, gantry cranes, polukozlovye, with supporting cables, cable cranes, stacker cranes, bridge cranes. The special type of boom cranes include jib, tower, portal, semi, mast, cable-stayed, cantilever and floating cranes. By construction, the lifting device and the appointment of distinguished hook, grab, pin, Hoisting, hardening, casting, landing, for undressing ingots, forging, and container cranes. If this has piqued your curiosity, check out Clayton Morris. The special features of special cranes, differentiating them from general-purpose cranes are allowed to include the following: a greater number of mechanisms, the likelihood of significant numbers of workers' movements, which is mainly from four to seven; limited use depending on the type of transported goods and the manufacturing process, equipped with special lifting devices winches and other machinery.

Overhead cranes (grab, grab magnetically with special lifting devices chord, ring, radial, rotating carriage, or traverse, manual hoist, single-beam suspension, etc.) are used in various industries. Cranes with special means of handling use, for example, to transport the slabs. They have better performance compared to performance overhead crane hook. Gantry cranes are used for bulk cargo warehouse at hydroelectric power plants, in shipbuilding docks. Gantry crane bridge is different from the fact that it is based on the bridge Crane by way of supports and the bridge overhead cranes is based directly on the overhead crane to crane, or road way, fixed on the beams, mounted on the pillars of the shop or on the viaduct. Design of gantry cranes terribly different. If possible, they are moving from stationary and mobile. Stacker cranes are used mainly for general cargo warehouses.

Distinguish overhead rack and stacker cranes. Crane-conveyors, bridge cranes for construction of nearly similar to gantry cranes. They are mainly used in warehouses piece and bulk goods. Bridge cranes are relying on two pillars, moving crane on tracks. In difference from the gantry cranes overhead cranes have zdorovuschy span, 100 m and more. These are often done on the console. Due to the large thermal strains bridge cranes one of the pillars typically perform "Flexible", ie, this support is connected to the bridge with a cylindrical or ball joint. When the spans of 150 m and more weight overhead bridge crane creates tensions that are close to the yield of the material. For large spans using mostokabelnye cranes, which passes under the bridge carrying the rope, whose ends are attached to the supporting pillars. Trolley moves along the supporting rope. Such a construction crane helps significant reduction in weight of the bridge. Consider the scope of the special crane boom type. Largest group of these cranes are cranes that are used mainly in sea and river ports to overload piece and bulk cargo vessel, warehouse, ship, and also in warehouses, ship building and construction. Gantry cranes are a full-circle jib cranes, revolving set to share portal crane moving on rails. In the gantry cranes when the flight trajectory of the load close to the horizontal.


What kind of fibers the same question? In the first all – of the heat-resistant, able to work for a long time at high or very high temperatures. Then – about hemostoykih that can withstand prolonged contact with the most aggressive chemical environments: strong acids, alkalis and oxidizing agents. And finally, the question is, apparently, of the fibers used in one of the most important areas such as medicine, particularly in surgery and alloplastica. Technique every day increases the demands on heat resistance, heat resistance materials. Two or three years ago, we were not aware of fibers and fabrics, can hundreds of hours working at a temperature of 250-300 , without compromising the strength or failure. And now required for fiber work in more severe conditions – at temperatures above a thousand degrees.

And these synthetic fibers have already been established. True, the "work" as long as they only a few minutes. But the thing that has identified ways to address this complex and very important technical problem. The search for chemists working in this field are focused generally on certain classes of synthetic polymers, especially hetero. Macromolecules of the substances containing aromatic ring, different stiffness – it makes heat-resistant polymer.

On the basis of precisely such polymers, American scientists have created two years ago, polyamide fiber-HT, the temperature "endurance" of which reaches 350-450 C. There are methods for producing fibers capable of withstanding a short time heating to 700-1000 . These macromolecules also have a cyclic structure. But this structure is not characteristic of the source material, it occurs in the fiber at a special treatment. What does this mean? Take, for example, normal poliakrilnitrilnoe fiber. It shrinks and loses its strength even at 150-180 . But start to warm up the fiber, slowly raising the temperature to 250-300 -and structure, and with it the properties of the fiber gradually changed.

Vosper Thorneycroft Engine

As a result of their propulsive performance modern water-jet almost as good as the propeller, and at high speeds and often exceeds it. Water cannon is very popular, where high-speed small craft should move freely in shallow water. Firm 'Vospauer' – a division of the famous British company 'Vosper Thorneycroft', which is building a small patrol boats and military vessels, has developed a series of water jets for advanced landing craft as the only engine of this allows such a vessel on the go 'pop' on the beach, and then weigh it on their own through the back of the jet, which drives the water under the hull. This advantage can be use and pleasure crafts, specially designed for 'landing' on unequipped shelving shore. Perhaps that is why the American company 'Hinckley' water cannon installed on their 36-foot model deykreysera, which by chance is called 'Picnic'. Safety – another positive feature water jet. The impeller is located inside the boat and not a danger to people nearby in the water.

This – the main reason for used water cannons and jet-skiers in tow. Rescue boats – another area where the water jets can play safety critical. In most cases, water-jet boat added solid fraction of the weight. Precise: not so much an engine as being in the water it constantly. When calculating the weight of the propulsion speed vessels of this water must be to add on to the weight of the vessel. Part of this added weight may compensated for the lack of line shafting gear as reverse and 'stop' provides a simple turn of the deflector (but in most plants need at least clutch between the engine and water cannons to the motor can operate independently of an engine operating mode).