Innovative gripper concept for simultaneous handling of up to four paper rolls
Demag Cranes received the order to supply eight fully automated process cranes and a warehouse management system from the Chinese company Anhui Shanying Paper Industry Co. Ltd. The cranes will be used in what will be in future the largest paper-roll shipping store in the world, constructed by Shanying Paper at its headquarters in Maanshan/China. In the store, the rolls produced by two new paper machines will be stored temporarily and prepared for shipping. The required high handling rates will be achieved by virtue of the fact that the cranes are equipped with mechanical roll clamps, which can hold up to four rolls at a time. Commissioning of the store is planned for the end of 2012.
Lu Zhao Jin, Vice General Manager of Shanying Paper states, “The investment in a new paper-roll shipping store forms an essential component of our rigorous growth strategy. With Demag Cranes we are focusing on a reliable partner with first-class references for this large-scale project.”
Dr. Lars Brzoska, Executive Vice President of Industrial Cranes at Demag Cranes, adds: “The paper-roll shipping store operated by Shanying Paper represents a further milestone in terms of storage capacity and handling volume. With the automated stores we have used to date, we have provided our customers with considerable support in increasing handling rates over the entire process chain of paper production. In this way, we have also developed a very good position for ourselves in the growth market of the Chinese paper industry.”
The largest paper-roll shipping store in the world
The Chinese company Shanying Paper, based in Maanshan in the province of Anhui, is considerably expanding its capacity for paper for corrugated cardboard tubes. To this end, in the second half of 2013 the company will be commissioning two new paper machines with capacities of 1,540 t of corrugated medium and test liner paper and 1,380 t of test liner paper and Kraft liner paper in daily operation. In order to ensure that this high production output is channelled, put into storage and delivered on time, Shanying Paper is investing in a new paper-roll shipping store. Over a total area of more than 23,300 m², the store is divided into two mirror-image buildings, with two bays each. With a theoretical filling level of 80 per cent, the store operated by Shanying Paper will hold a volume of 105,000 t of paper and will thus be the largest paper-roll shipping store in the world.
Process cranes for 24/7 operation for high handling rates
Just like the production facilities, the cranes will also be in operation 24/7. In each of the four bays, two cranes with load capacities of 4 t and a span of 35 metres will travel on 162-metre-long crane runways. The cranes will take the packed rolls and stack them in a tower-like fashion up to a height of 14.3 metres.
When planning the store, Shanying Paper placed great emphasis on optimum dynamics: up to 296 rolls can be handled per hour. In addition to an integrated storage concept, the high handling speeds desired by the paper producers require a very high level of performance by the crane installations. The long and cross-travel drives have infinitely variable speed control and reach maximum speeds of 120 and 100 m/min respectively; depending on the load, lifting motions are controlled at speeds of up to 81 m/min.
Secure handling: four rolls and a gripper
The mechanical grippers of the process cranes are a central requirement for the handling rates demanded by Shanying Paper. According to Lutz Dowy, Head of the Process Cranes business line of Demag Cranes: “The mechanical grippers can transport both individual items and sets of rolls. Since up to four packed paper rolls can be moved simultaneously, we will achieve the store handling rates required by our customer.”
To pick up paper rolls, the process crane is positioned precisely over the centre of the roll by the warehouse management system. Six gripper arms surround the rolls with even contact pressure to protect the material. The design of the gripper facilitates secure and gentle handling of the paper rolls. Additionally integrated safety circuits – such as the redundantly designed sensors installed in the gripper – provide for reliable and secure handling of rolls in automated storage processes.
Optimised roll storage
Thanks to the compact design of the mechanical roll clamp, the rolls can be stored in a tight grid. Best possible use of space is thus achieved. The packed paper rolls are stacked on top of each in columns, which in the case of the maximum roll diameter stand 150 mm apart. The gripper generation used at Shanying Paper has already been tried and tested at several other automated paper-roll stores in Europe and China.