New ASC from ZPMC

ZPMC has launched the “Model S-ASC” for automated container terminal operations. The new crane was put together by a team at ZPMC that includes three Deputy Chief Engineers, Yan Bing, Zhao Bin and Hu Jun, together with Senior Hydraulic Engineer Dr Song Yu, Intermediate Structural Engineer Dr Nie Feilong, Senior Electrical Engineer Yao Xuejin and Senior Mechanical Engineer Yang Zaihua.

The S-ASC includes a new hoist system where the hoist drive is optimised by increasing the rotating speed and reducing the output torque of the hoist motor, which allows the motor frame size to be reduced.

The hoist system also features permanent magnet synchronous technology with the reducer (or gearbox) located inside the hoist drum. Incorporating a planetary gearbox into the hoist drum is a well-known concept for crane winches and has been applied in some mobile harbour cranes. Used in the S-ASC, ZPMC says it simplifies the trolley frame and reduces the trolley weight.

New structure

The revised gantry structure of the S-ASC has been optimised, based on Finite Element Analysis optimisation theory, to increase stiffness, strength and fatigue life. The crane rail support web has been redesigned to be thicker and deeper, making the structure stronger and more reliable under trolley wheel loads, ZPMC said.

The more rigid upper design allows a flexible leg that is simpler to construct, with no stiffeners, diaphragms or inner welds, and a lower wind load.

At the gantry travel level, the S-ASC features 600mm diameter gantry wheels and a lower height to the equaliser beam gantry pin measured from ground level.

ZPMC has eliminated the neck connection between the equaliser beam and the bogie and incorporated a gearmotor drive with an integrated motor, gearbox and brake.

Other parts of the crane structure have been redesigned to optimise the structure and reduce weight. This includes the layout of the main electrical equipment, the cable tray and cable ladders. It is possible to use aluminium alloy to reduce weight further. Using a “module station”, ZPMC has reduced the weight of cables crossing the main girder and the number of joints that can be points of failure.

The crane control system features what ZPMC calls “robust self-adaption control with strong anti-interference capability” that was developed by ZPMC jointly with Zhejiang University, in Hangzhou.

Three common features

The S-ASC is a series of cranes with three common “S” features. S1 is “Swift” – the crane has been developed to shorten the design period. A model S crane can be configured through menu selection, including 41t and 50t SWL options, different spans, lifting heights and wheelbase options for the crane structure.

For the crane operating parameters, different hoist speeds ranging from 30/60 m/min laden and empty to 45/90 can be selected. Gantry travel options range from 120m/min to 300 m/min if high-speed travel is required.

For the anti-sway system, users can select ZPMC’s “full functional” system, a conventional eight-rope system or ZPMC’s own eight-rope design. Additional sub-system options include load collision prevention, truck positioning, OCR for container number recognition, CCTV, anti-collision sensors, truck anti-lift and gantry collision prevention systems and a lighting protection system.

For construction and assembly, ZPMC has divided the S-ASC into 20 modules. Each is independent, complete with all the necessary electrical systems, cables and shipping attachments. The whole crane is designed for containerised shipping and “lego-like assembly”, making on-site erection possible.

Delivering high productivity

ZPMC is confident the S-ASC can shorten delivery times while delivering an ASC that “functions faster” and is more agile. While the design is new, all the components are tried and proven.

In terms of overall efficiency, the S-ASC is designed to reduce the moving mass, while at the same time delivering high productivity by “moving faster”, ZPMC says.

Energy consumption per TEU is reduced by 15-20% compared to a conventional ASC and the crane can deliver 23-25 moves per hour. This figure is based on an average gantry travel distance of 100m per container move.

*This story first appeared in the September print issue of WorldCargo News