I, Dismantling of the tower crane
Disassembly sequence: Tower Crane lowering (lowering to roof height) → Counter weight (leaving one counter weight at the third position forward from the end of counter jib) → counter weight → counter jib→ tower head → cab → slewing mechanism → jacking cage and standard section.
II, Specific disassembly process of tower crane
As there is not enough space and site on the construction site, consult with the manufacturer. The disassembled parts shall be removed as soon as possible, loaded in sequence and occupied as little as possible. The specific lifting procedures are as follows:
1. Before lowering the tower crane, check whether the limit devices and safety devices of the tower crane are sensitive and reliable;
2. Preparation before tower crane reduction;
1) The hydraulic system must be checked for normal operation before the reduction.
① Check the oil quantity and quality of the oil tank;
② Check whether the control valves and hydraulic pipeline system are normal;
③ Check whether the air in the oil pump is drained;
④ Check whether the sealing system of oil cylinder is damaged or aged;
⑤ Check whether the pressure meets the requirements of jacking pressure;
2) Unsafe factors exist;
① Insufficient oil volume or poor oil quality of the oil tank will cause the oil cylinder to fail to work normally;
② Damage of valve and hydraulic pipeline system will lead to leakage of hydraulic oil;
③ There is air in the oil pump, which will lead to hydraulic instability and sudden drop during jacking;
④ Damage or aging of oil cylinder sealing system will cause oil leakage, which is easy to cause sudden sliding during jacking;
⑤ If the pressure does not reach the requirement of jacking pressure, the operation of lowering section cannot be carried out normally;
3) The safety and quality of the attached wall parts must be checked before the reduction
① Check whether the coupling screws of the jacket are tight;
② Check whether the split pin of the coupling pin shaft is out;
③ Check whether there are cracks in the welds of all parts
④ Check the wall connected with the pull rod for cracks;
3. Precautions in the process of downsizing
1) After the connection between the standard section and the lower slewing support is removed and before the completion of the lowering, it is forbidden to rotate or operate the boom in this process;
2) In the process of lowering operation, there must be a special person to command, take care of the power supply, operate the climbing mechanism and fasten the bolts. Non relevant operators shall not board the operation platform of the climbing frame, nor start the pump valve switch and other electrical equipment without permission;
3) The lowering operation shall be carried out in the daytime. In case of special circumstances, the operation shall be carried out at night with sufficient lighting;
4) Only when the top wind speed is lower than 13m / s, the lowering operation is allowed. If the wind force suddenly increases during the lowering operation, the lowering operation must be stopped, and the pin of rotation and bracket shall be pinned to connect the inner and outer tower bodies;
5) In the process of joint lowering, the slewing mechanism shall be tightly braked, and slewing and other operations are strictly prohibited. If any fault is found, stop the vehicle immediately to check the cause and do not remove the fault. Climbing operation is not allowed;
6) When the tower body is lowered to the specified height, it is not allowed to dismantle the attached wall device first;
7) In the process of lowering the pitch, the removed bolts shall be coated with lubricating grease;
8) After the lowering is completed, the standard section must be tightened with the bolts of the lower slewing support.
4. Tower lowering operation of tower crane
① . adjust the clearance between the guide wheel of the climbing frame and the tower body. Move the position of the trolley to make the center of gravity of the upper part of the tower crane fall on the hinge point of the jacking oil cylinder. Then remove the eight high-strength bolts connecting the support and the tower body, and check whether the climbing claw affects the lowering operation of the tower crane.
② . start the hydraulic system, after all the piston rods are extended, hang the jacking beam on the next step of the tower body, remove the connecting bolts between the tower body and the tower body, slightly lift the piston rod, separate the upper and lower supports from the tower body, and push out
The standard section is to the top of the introduced crossbeam, and then all the piston rods are retracted, so that the crawling claws are placed on the steps of the tower body, all the piston rods are extended again, the jacking crossbeam is hung on the upper step of the tower body again, all the piston rods are retracted, the upper and lower supports are connected with the tower body, and high-strength bolts are inserted.
③ . the above is a tower lowering process. Repeat the above process when lowering the tower continuously.
5、 Remove to the basic height of the initial installation, and use the truck crane to assist the removal; the removal must be carried out according to the removal sequence.
Disassembly steps;
1) According to the tower crane operation procedure, lower the tower to the initial installation height, and remove the wire rope of luffing and lifting mechanism.
2) Use the truck crane to disassemble the tower crane, first remove the counterweight, and only retain the counterweight from the boom tail to the tower body.
3) Removal of boom: the truck crane slightly lifts the boom, the steel wire rope with lifting mechanism bypasses the tower top and the pulley block on the boom tie rod to remove the boom tie rod, then the pin shaft at the boom root is removed, and then the truck crane boom is lifted to the ground.
4) After removing the remaining counterweight, the truck crane slightly lifts the balance arm to remove the tie rod, and then when it reaches the horizontal position of the balance arm, the pin shaft at the root is removed, and the balance arm is lifted to the ground.
5) Removal of tower head.
6) Remove the cab and swing mechanism assembly. Before removing the pin shaft and bolt between the rotary table and the jacket, fix the jacket first.
7) Remove the jacket and standard section.
Note: in the process of disassembly, special personnel must be assigned for on-site safety supervision, and it is strictly prohibited to allow people to pass in the operation site. At the same time, set up warning lines and obvious signboards.
