Research on the Standardization of Rail Mounted Gantry Crane Specifications -Ⅰ
At present, the rail mounted gantry crane specifications are confusing both at home and abroad, I will share my research on the specifications standardization of rail mounted gantry crane in two articles, this article is mainly about the rail distance and extended distance.
In our country, there are mainly two types of process system for specialized container terminal yard, rubber tyred gantry (RTG) crane, and rail mounted gantry (RMG) crane. With the continuous deepening of energy-saving and emission-reduction work, rail mounted gantry crane has been replacing the position of RTG, becoming the most vigorous force in yard machinery model, which is in the result of various of advantages of RMG crane, such as low operation cost, small noise pollution, low failure rate, high site utilization, energy saving, environmental protection, in line with national industrial policy, and so on.
At present, rubber tyred gantry crane has been standardized basically, the span is 23.47m (6 rows of containers plus 1 lanes), without outside extension. However, there are various of structure types of port rail mounted gantry crane, most of the container terminals determine the rail mounted gantry crane specifications according to their respective conditions. Main rail mounted gantry crane specifications, such as lifting capacity, lifting height, span, sped, control mode, and so on are all used from the lowest to the highest, caused there are multiple types of rail mounted gantry crane, even confusion, hampered the rapid development and application of rail mounted gantry crane.
Current situation of rail mounted gantry crane specifications
At present, the rail distance of rail mounted gantry crane is generally within the range of 15-60m, extended distance is generally not more than 10m, most of the lifting height are around 15m, for heavy container, stacking 3 over 4, stacking 4 over 5, stacking 5 over 6 are most used, for empty container, stacking 7 over 8, stacking 8 over 9, even stacking 9 over 10. With the continuous development of economy and continuous improvement of science and technology level, the speed requirements of cranes are getting higher and higher. Lifting speed of full load up to 45m/min, for no load is 90m/min, maximum running speed of trolley can up to 150 m/min, running speed of running bridge up to 270 m/min.
According to statistics, proportions of rail mounted gantry crane with different rail distance all over the world are: rail distance of 20~25m account for 20.80%; rail distance of 26~30m account for 32.12%; rail distance of 31~35m account for 28.47%; rail distance of 36~40m account for 5.84%; rail distance of 45~50m account for 21.82%. Rail mounted gantry crane with rail distance of 26~35m are most widely used. But at present, with the rapid development of international container transportation business, the requirement of rail type container gantry crane is more and more high, the rail distance, 35~40m is also common.
Research on standardization of rail mounted gantry crane specifications
Main specifications of rail mounted gantry crane include rail distance, extended distance, lifting height, base distance. Lifting height is determined according to the stacking layer, base distance is determined according to whether through the 40ft container. In this article, we only research on the standardization of rail distance and extended distance.
At present, the minimum rail distance rail mounted gantry crane at home and abroad is 15m, the maximum is more than 60m, which is determined mainly accordance with the site condition. Compared with rubber tyred gantry crane, span of rail mounted gantry crane is smaller, the basic investment is large, resulting in resources waste. On the contrary, if the rail distance is too large, it will result in a high rate of container overturning, low efficiency of loading and unloading. Therefore, it is advised to adopt the rail distance of rail mounted gantry crane within the range of 25~60m.
In this article, we research the rationality of rail distance mainly from the aspects of loading and unloading technology. Loading and unloading track of rail mounted gantry crane with outside extension is arranged outside the span, crane without outside extension is arranged inside closed to the leg of door. Trucks can pass in and out the loading and unloading area for handling operation, which is convenient to link with the external rail.
Space between yard container is generally 0.3~0.4m, width of loading and unloading rail for container is not small than 3.5m. It is safety to stack containers at the position away from the rail of rail mounted gantry crane 1.5~2m, so as to obtain the calculated value and recommended value of rail range for rail mounted gantry crane are shown in Table 1.
|No Rail between the Span||One Rail between the Span||Two Rails between the Span||
|Rows of Containers between the Span||Calculated Rail Distance L/m||Rows of Containers between the Span||Calculated Rail Distance L/m||Rows of Containers between the Span||Calculated Rail Distance L/m|
There are various of extended distance for the exiting rail mounted gantry cranes at home and abroad, which are within the range of 3.5m to 16m. The value of extended distance is determined according to rail arrangement and container stacking conditions, the larger extended distance is, the larger the structure size is, in order to guarantee the stiffness of structure, which results in higher manufacture cost. Thus the outside distance shall be set by considering the above factors, should not be too large. Usually, if the span was both set rail and piled containers, it is easy to cause danger because the row of stacking is smaller and the stability is poor, but the rail mounted gantry crane with large extended distance arranges the container position outside the span sometimes.
According to the container spacing, rail width and safety distance, we can calculate the range value of extended distance for rail mounted gantry crane. Synthesis of three cases, recommended value of the extended distance is shown in the following table 2.
|Only Rail Outside the Span||One Rail + Stacked Containers||Two Rails + Stacked Containers||Recommended Extended Distance D|
|Row of Rail Out of Span||Calculated Extended Distance||Row of Rail Out of Span||Calculated Extended Distance||Row of Rail Out of Span||Calculated Extended Distance|
In the next blog, we will still discuss the standardization of rail mounted gantry crane specifications from the aspect of motion specifications and recommended specifications.