The universal tire-type container gantry crane (referre […]
The universal tire-type container gantry crane (referred to as the universal RTG) is an important equipment in the container port and dominates the modern port container yard. It can be flexibly mobilized in a wide range, with high space utilization, high productivity and full container spreader yard maneuverability. However, the general-purpose RTG uses diesel generator sets to provide power for the whole machine, and has the disadvantages of high cost, high daily use and maintenance cost, high energy consumption, exhaust emission pollution, and noise pollution. According to statistics, the energy consumption per standard box of general RTG operation is 1.2-2.2 liters of diesel.
The new tire-type container gantry crane is a large-scale mechanical equipment, and its main energy consumption in the production process is electricity. Since the new RTG is a light-weight device, the weight of the whole machine is reduced by about 1/3, so a lot of energy can be saved in the production process. At present, the application of this technology can achieve energy saving of 40,000 tce / a, CO2 emission reduction of about 110,000 t / a.
1. Technical principle
(1) Adopting "four reels" combined drive technology
In the overall design, the new RTG uses four sets of wire rope reel devices (see Figure 1), relying on the positive and negative revolving of the reel, retracting the wire rope to achieve lifting and lateral movement of the cargo. The drive unit and the reel are mounted on the sill of the gantry. Compared with the universal RTG (the hoisting and trolley running mechanism are set on the trolley), the quality of the trolley and the center of gravity of the whole machine are greatly reduced, and the structure of the whole machine is optimized. The weight of the whole machine is lighter.
(2) using electric drive
The general-purpose RTG uses diesel generator sets to provide power. Since the system load is variable and non-linear, the general-purpose RTG is at a rated speed and partial load operation when the load is light, and the diesel generator set is inefficient. According to statistics, after the general-purpose RTG engine is started, the time for loading and unloading operations is less than 50%. The other time is air consumption. A general-purpose RTG consumes about 15 liters of diesel per hour. The new RTG working motor and lighting are powered by utility power, and only equipped with low-power diesel-motor diesel engines as transitions to meet RTG maneuverability requirements.
(3) Electric drive control
The electric RTG adopts frequency conversion speed regulation, programmable controller (PLC) and field bus control to form an electric drive control system to realize speed regulation and control integration. The main control unit of the whole machine is connected to the bus in the form of nodes to realize digital signal communication, which has the characteristics of fast and accurate. At the same time, a large number of signal lines between the control units are saved, which simplifies the hardware system and reduces the cost.