The hottest steel strand Jack crane system

2022-08-09
  • Detail

Steel strand Jack crane system

although the lifting capacity of the crane continues to improve, the use of the crane is often hampered by space constraints, equipment installation time or lifting weight requirements. Sometimes, the steel strand jack is often the only way to solve the problem. British zalcon company is a professional steel strand Jack company, which has been committed to promoting the steel strand jack system for engineering. The company believes that this is the safest solution with the best cost-effectiveness ratio in heavy lifting engineering. The steel strand jack of the company can replace the crane and is mainly used in construction, petrochemical and offshore engineering. There may be competition with large cranes in the petrochemical industry, but they prefer to use steel strand jacks instead of hoists to lift loads

1 advantages

(L) safe and reliable. Although the lifting pulley block of the crane has multiple ropes, only a single steel rope leads to the winch. The steel strand jack system can have as many as 51 steel cables on a jack, and the safety factor of the steel cable is 2.5, that is, when the minimum breaking force of a single steel strand is 38t, its rated working load is only 15t (zalcon uses a prestressed steel strand with a diameter of 18mm for strengthening concrete)

(2) large lifting capacity. The maximum load of a single jack of zalcon company is 775t. When it is combined into a lifting system, it can lift large components weighing thousands of tons, which is unmatched by general large cranes

(3) the working speed can reach 60m/h, and it can work when the wind speed is greater than 9m/s. Although compared with the crane, the latter has higher winch speed, which can save time, especially in a limited climate with computers, it can show its advantages, but this is not a big problem. Too high lifting speed requires high-power units and is expensive, so the commonly used working speed is 20m/h. The working site is small, and components higher than the jack tower can be installed. Compared with large cranes, steel can be used as handwheel and adjusting handwheel to check whether each part operates flexibly. The strand jack system does not need a lot of foundation, and there is no need to carry out more ground preparation in advance. It can be clearly seen from Figure 1 that with the assistance of other lifting equipment, large containers much higher than the jack tower can be installed

(5) the standard tower modulus system can provide perfect engineering solutions, including a complete set of design and supply equipment

2 Jack

zalcon company can provide 9 standard models of steel strand jacks. Increasing the size of runner and gate can reduce the shrinkage working load from 15t to 775t. The jack is easy to maintain and has a variety of control operations. It is a very important work to thread all the steel strands into the jack. The company adopts an optimized circular mold to make the stress of the steel strands correctly in the center of the whole steel strand bundle

the system uses double acting micro jacks to directly open or lock the anchors at the top and bottom, rather than relying on unloading to loosen the wrong tools. The lifting weight is usually lowered by power, but it has an oil drainage system to slightly reduce the lowering action, rather than putting the lifting power to the end. Both the main jack and the micro Jack are equipped with a working position monitoring system. The jack lifting system uses a programmable logic controller to realize automatic control, so the jack works circularly in the operation without manual operation. Unlike other jack systems with only one fixed working speed, zalcon can provide a speed change system composed of an electro-hydraulic control unit installed on the jack, and all jacks are interconnected to ensure synchronization. When designing a lifting scheme, in principle, priority should be given to the use of the minimum number of large jacks rather than more smaller jacks. Sometimes it depends on the actual situation. When the lifting weight is a member with a large top, a lifting point cannot be used due to insufficient rigidity

3 engineering example

3.1 equipment installation of Taiwan Plastic petrochemical plant

zalcon company installed a device with a total of 40 containers for a Taiwan Plastic petrochemical plant. In this project, a common tower top is used for the lifting of 36 containers, and a new tower top is developed to install the other 4 containers

the company provides the construction design of the plant, especially the construction design of the maximum container size limited by the installation and construction technology. In the first stage of the installation project, vessels with a maximum height of 81.6m and a maximum weight of 1062t were hoisted in May 1997; The second stage is from May to July 1999. A different type of crane is used, but attention should be paid to the top of the heavy tower, and four containers with a maximum of 115m and a weight of 1600t are installed. All lifting and installation work is assisted by a liebherrlri 650 crawler crane with a "super lifting device" and a lifting capacity of 800t. In the new design, the straight beam is replaced by a U-shaped frame on the top of the tower, and four wind cables are installed. Its main advantage is that it can reduce the height of the tower, and the jack does not have to be set on the height of the whole container. The U-shaped frame is optimized by finite element method. Four za1250 jacks (each with a tension of 580t) are installed on the U-shaped frame for lifting. The U-shaped frame is also equipped with an internal combustion hydraulic power unit, which is remotely operated from the control room on the ground

four za235 105T jacks (see Figure 2) are used for the cable wind rope, which can easily measure and adjust the tension of the cable. Each of the four cables is anchored with 475t concrete ballast

.2 the maintenance project of the petrochemical plant in the west of Java, Indonesia

steel strand jack can also be used for the removal and replacement of containers in existing plants. Zalcon company won the replacement contract for four 60t final coolers of two polyethylene units in Indonesia. Before that, the factory had considered several other options. The first option is to use Demag cc2600 or cco2400 large crawler crane, but it is excluded because the pipe support hinders the assembly of the crane at the lifting place, and some structures need to be removed from the top of the container, as well as the need for pile foundation. The second option is to use a gantry and a smaller crane (such as Demag a CI 600) to lift the container and slide it out, but this scheme has also been rejected, because in addition to the pile foundation of the crane, some structures need to be removed for sliding operation, and the safety inspection of the gantry needs to be carried out

the currently selected solution (Figure 3) also requires the removal of some structures and the ability of the structure to hang the gantry load must be tested in order to build a gantry with cantilever and slide rail, remove the container from the structure, and then lower the container to the ground with a steel strand Jack installed on the extended gantry. This method does not need a large area of foundation, which is cheaper and easier to master than using cranes. This project is to replace two corroded coolers. In some cases, some containers need to be replaced every two years. Therefore, the company has purchased equipment for future application in similar projects

in the initial stage of the replacement of the first set of devices, before the shutdown of the main machine, it is necessary to strengthen the structure, remove some support rods to get close to the container, then install the slide rail, gantry and Jack equipment during the shutdown of the main machine, and then lift the container with a jack, connect it to the gantry with a pin shaft, move it out of the structure, reach the cantilever frame, and finally lower it to the ground with a steel strand Jack. When installing a new container, proceed in the reverse order of removal

Copyright © 2011 JIN SHI