Jacking Method Is More excellent Than Traditional Method for Field Erected Tanks
Comparison between traditional method and jacking method
Large vertical storage tanks generally refers to the storage tanks whose diameter is more than 5 meters, especially those whose maximum diameter can up to 40m-50m and the maximum height can up to more than ten meters. For the fabrication and installation of these kind of large storage tanks, as it is unachievable to transport a assembled tank, field erection is the most commonly method. There are several erection methods for field erected tanks, such as traditional method, jacking method, and integral lifting after the site prefabrication.
The traditional method is erecting on ground base of storage tank, after one section is assembled, the scaffold tower will be added a layer as the tank increased, because of the high operation, this method is more dangerous.
What is jacking method?
Jacking method is a storage tank erection method based on the tank bottom as datum plane, the top wall plate and tank roof is installed firstly, then assemble, weld and jack the wall plate step by step alternately until the bottom wall installation is completed in sequence. The jacking method is a common method for construction and installation of large storage tank at present, which owned many kinds of technology and corollary equipment, and one of the most advanced, reliable and vigorous method is hydraulic jacking technology, which is suitable for lifting large storage tank(dome-roof tank, floating roof tank, internal floating roof tank, steel mast, communications tower and steel spire, etc.) construction.
Tank Erection Hydraulic Jacking System
Tank lifting hydraulic jacks (or equipment) are evenly distributed on the inner wall circumference of storage tank, the tank roof and the upper layer wall plate (first floor) of tank body are lifted firstly, then tank wall plate will be installed and welded layer by layer.
Adopt hydraulic lifting machine composed of self locking type hydraulic jack, lifting frame and lifting rod, when the hydraulic jack adds oil, the lifting lever and expansion ring will be chucked and lifted through its top clamp, then driven the tank body (including the roof) upward. When the hydraulic jack returns oil, the clamping head on the top of it returns back with the position rod. In this case the lower clamping head automatic clamping lifting rod will not decline. This repeated motion of the jack make the lifting lever rising the tank continuously until the tank arrive the predetermined height (the next plate height is vacated). After the next layer is welded, open upper and lower card device of the jack, loosen the upper and lower chuck and make the lifting lever and the ring down to the next layer of wall plate. The lower is swelling and welding the dowel steel plate then improving it. Operate repeatedly, make the welded tank rising until the last layer of compound wall plate is complete. Thus the whole tank installed completely.
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Hydraulic tank jacking method lifting advantages
- Hydraulic lifting is stable, safe and reliable. Due to the hydraulic unified control, and can make a single or partial (several) adjustment, the whole lifting process is stable. The structural characteristics of loose hook jack determines its own excellent self-locking, the tank or heavy objects will not fall down because of power outages. Hydraulic lifting process is safe and reliable.
- Construction quality can be guaranteed. Because of adjustable (micro drop) functions of the loose hook jack, the hoisting height can be controlled more precisely. For the above-mentioned reasons, tank construction quality can be guaranteed.
- Equipment is easy to operation. Good construction environment and high working efficiency.
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Equipment adaptability is strong. The complete sets of equipment Large hydraulic tank can be applied to the hydraulic lifting construction of large storage tanks (or steel masts, communications towers and minarets steel, etc.) with volume from thousands of cubic meters to tens of thousands cubic meters, as long as increase or decrease the hydraulic lifting machine (loose hook jack, lifting frame, lift bar, etc) quantity.
According to the actual working condition, the hydraulic pump station can be installed in a reasonable position. For the large-scale storage tank, hydraulic pump station can be placed inside the tank, outside the tank, or in the middle of two tanks (when two tanks installation is controlled by a pump station) to control the construction.
Pump station can be divided into manual control and automatic control. Its characteristics of adaptable construction and excellent technical cost performance are very obvious. - Short duration, low cost, good economic returns. Because of the high degree modernization of complete sets of equipment and fast lifting speed, the construction costs is low and economic performance is excellent.
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Overall, the jacking method does have characteristics of convenient centralized control，easy to operate, safe and reliable (do not sag), precisely control the weld gap and heavy lifting lever height. What’s more, jacking method can not only ensure the engineering quality and save labor, but also can reduce costs, and have a significant economic benefit.
