News Detail
From the perspective of the technical development of the shipbuilding door diesel engine crane, it is mainly reflected in three aspects.
In the early stage of our design, the double-girder structure is generally used, such as the 300t×116m gantry crane of Nantong COSCO Kawasaki and the 480t×122m gantry crane of Bohai Shipyard. With the increase of the crane span, the problem of the lateral stiffness of the main girder of the double-girder gantry diesel engine crane becomes more and more prominent, causing the upper trolley to deviate. Therefore, the large-span shipbuilding gantry diesel engine crane generally adopts the structure type of single beam.
we have improved the frame structure of the upper trolley of the double-girder gantry crane for shipbuilding, adopting rigid and flexible legs similar to the gantry structure, and using a rigid and flexible frame structure to solve the problem of the upper trolley. The problem of the trolley running off-track has been patented.
At present, the overall structure of large shipbuilding gantry diesel engine cranes basically adopts two forms of double girder and single girder. The span of double girder has reached 208 meters, and the span of single girder has reached 239 meters. These two forms have their own advantages and disadvantages: the double beam is easy to maintain, the height of the three hooks is the same, the main beam is simple in structure and easy to manufacture, but the self-weight is relatively heavy; the single beam is light in weight, but difficult to maintain under the car. Two forms of shipbuilding gantry cranes are generally designed according to user requirements.
The institutional form of large shipbuilding gantry diesel engine crane has been greatly improved. Due to this type of gantry crane, the lifting height is generally about 80 to 90 meters, and the lifting weight of a single hook is 300t to 500t. How to reasonably configure the form of the hoisting winch and reduce the weight of the trolley is one of the main goals pursued by the design. Due to the large lifting capacity and high lifting height, the gantry crane designed in the early stage generally adopts the double drum form for the lifting winch. The reel is arranged on both sides of the upper trolley, and the wire rope is directly lowered from the reel to the hook pulley block. Since the weight of the components and the load weight are both at the cantilever end of the upper trolley, the upper trolley is heavy.
At present, in the layout of the hoisting mechanism of the trolley, we generally use a single-drum hoisting winch and a chain-driven winch rope arrangement. The winch is arranged in the middle of the trolley, which not only reduces the weight of the winch, but also uses the winch The weight balances the weight of part of the lifting load, thereby reducing the self-weight of the trolley. With the improvement of the overall manufacturing level of my country's machinery industry, the hard tooth surface reducer has replaced the medium hard tooth surface reducer, and the new structure of the wire rope has replaced the traditional steel wire strength, which also further reduces the weight of the mechanism. Compared with the dead weight of the traditional trolley, the weight of the new trolley can be reduced by about 1/3.
The electrical control system of the large shipbuilding gantry diesel engine crane generally requires higher speed control and safety protection for each mechanism. At first, the DC speed control system was generally used, but with the improvement of the frequency conversion control technology, most of the current frequency conversion control systems are used, which reduces the investment cost, improves the reliability of the control, and facilitates daily maintenance.
Large-scale shipbuilding gantry diesel engine cranes generally have higher requirements for the lifting and walking of the upper and lower trolleys, the walking mechanism on the rigid leg side and the flexible leg side of the trolley, and the synchronization of the two cranes. At present, in the synchronization of the hoisting structure, the absolute value encoder is used for detection and control, and on the walking mechanism (including the rigid and flexible legs of the upper and lower trolleys and the cart), the absolute value encoder installed on the detection wheel is used to measure the walking distance. For the control of the detection, for the traveling mechanism of the cart, the ground induction switch is added to correct the possible error of the encoder, and the out-of-tolerance limit switch is installed at the flexible hinge to prevent the extreme situation. The installed capacity of large shipbuilding gantry cranes is relatively large, most of which are around 2 to 4 kilowatts, so the requirement for energy saving is also one of the factors to be considered in the design. The current energy-saving design generally adopts AFE (IGPT) public DC bus, and the drive system with energy regeneration feedback can save a lot of energy (about 20~50%) in actual operation.
The safety protection of large shipbuilding gantry diesel cranes is more prominent than that of ordinary cranes. In addition to the conventional safety protection functions, we also installed industrial video systems, laser anti-collision systems, crane management systems, etc.
In order to keep abreast of the use of diesel engine cranes, when the equipment fails, we can analyze the cause of the failure and guide the maintenance work in time. On some cranes, we have also added a remote monitoring system, which can use the Internet to know the use of the equipment in time and guide the failure.