2 ZPMC’S TEN TECHNOLOGY ACHIEVEMENTS OF RTG
Unit 2
1.1 Text
ZPMC’S TEN TECHNOLOGY ACHIEVEMENTS OF RTG
With the rapid development of container transporting，ZPMC has developed standard rubbery-tyred gantry cranes to me et the customers’ high requirement of supplying cranes with high quality and short delivery time. There are two kinds of RTGs based on wire rope reeving system：one is provided with mechanical sway-damping system with four anti-sway wire ropes，the other one with eight anti-sway wire ropes(which can achieve bi—directional anti-sway). Through modulization , the crane and its parts and components can be standardized and commonly used ZPMC can better serve customers with high—quality and short delivery time. Meanwhile ZPMC can also supply non-standard heavy-duty rubber-tyred gantry crane of hoisting 50t and 60t load, and RTGs hoisting one over four containers(1+4)or one over six containers(1+6)．Besides．we can provide other non-standard rubber—tyred gantry cranes, such as RTG with sixteen gantry wheels.
1.Principal parameters
1)．Rated lifting capacity under spreader：40LT
2)．Rated lifting height：18.1m (1 over 5)
3)．Span：23.47 m (77’)
4)．Number of gantry wheels：8
The distance of wheel centre to centre under all equalizer：2.5m
5)．Wheel base：6.9 m
6)．Lifting speed：23／46～52 m／min
7)．Trolley traveling speed：70 m／min
8)．Gantry traveling speed：25／100 m／min
9)．Spreader skewing：±5 degree
10)．Anti-sway type：mechanical
l1)．Spreader micro-movement with eight wire ropes:
±250mm along gantry drive direction and
±200mm along trolley drive direction
2.Ten new technology
1. Green RTG
ZPMC adopts super capacitor (the maximum of each is 100,000 farads) as an energy storing device to be inserted into the electric circuit. The huge energy can be stored and released instantaneously, and the peak value power can be compensated. The diesel
engine and generator set can be ensured to operate under stable condition. The Green RTG can successfully protect the environment.
It has the following good performances:
1） Obvious improvement of diesel engine exhaust.
No black smoke appear from the exhaust pipe;
Particle exhaust thickness is reduced by 90.5%;
CO2 exhaust thickness is reduced by 35%;
Nitride and oxide exhaust thickness is reduced by 30%;
CO exhaust thickness is reduced by 13.3%;
2） The noise of diesel engine is reduced by 4~5dB under sudden load condition. 3） The energy consumption is reduced by 11~13% (in accordance with the compared operation data).
4） The stability of the diesel engine can be increased, and its service life is extended.
2. Application of GPS on RTG
In order to ensure RTG’s straight traveling, ZPMC has developed GPS on RTG. Its features are listed as follows:
1） GPS can establish a set of “simulating rail” on the terminal by means of ground difference system. Thus, RTG’s gantry auto-steering can be achieved, and operators’ fatigue can be reduced. The accurate positioning of gantry straight traveling can be accomplished with the accuracy of positioning up to +/-15mm. 2） Container position management at yard can be carried out by GPS positioning and remote information transferring technology. The accuracy of container positioning information at yard can be improved.
3） The gantry traveling speed can be increased by means of GPS. The RTG can travel at full speed at fully-loaded yard with no worry about hitting with containers.
Thus, the productivity is increased.
3. Bi-directional (8 Ropes) New Anti-sway Technology
The traditional hoisting reeving system is changed to four completely identical reverse triangle systems to increase the rigidity of hanging system by using the geometry principle of triangle stability. The anti-sway function can be accomplished by the spreader, and the spreader (also the container) stops after the trolley starts or brakes.
The advantages of RTG with bi-directional anti-way function are as follows:
1）When the container is 1.5m above the ground and the trolley or gantry stops at full speed, the maximum swaying distance is not bigger than 50mm. But the anti-sway mechanism on the traditional RTG can have such result after swaying for 10 seconds.
2）The spreader’s movement back and forth, right and left, and skew function can be carried out through the special device installed on the headblock. This greatly reduces the operator’s positioning time.
3）Because the spreader can stop as soon as the trolley (or gantry) stops, the semi-automation and full-automation can be accomplished on RTG.
4）Compared with the tradition RTG that is provided with normal mechanical sway-dampening mechanism, because the RTG with bi-directional anti-sway
function is not equipped with electric thruster, single-directional bearing, torque motor and blower, it can avoid the high fault rate happened on the traditional RTG that is equipped with more mechanical and electric parts. Both the daily maintenance and repairing costs are greatly reduced, and the manpower cost and the other costs including work and vessel delays are also greatly reduced.
4. RTG With No Gantry Chain Drive
The gantry drive on the current RTG in the world normally adopts motor, gear reducer, and open type chain drive. Because of the increment of RTG’s weight and huge inertia caused by abrupt braking, the driving chains are easily broken, and the service life is shortened. ZPMC developed a kind of RTG with fully gear driving, that is, the direct driving of the gear reducer is adopted, and the traditional driving chains are deleted. The fault rate of the gantry driving is greatly reduced, and less gantry driving maintenance and high efficiency can be ensured. 5．Gantry Turning Jacking Device
RTG has frequently gantry turning. During the gantry turning, the tyres also need to rotate 900. When the tyres are turning at their fixed positions, not only the tyre surface abrasion will be increased greatly under the big wheel load (normally bigger than 25T), but also the big stress on the tyre inner sealant and cord fabric will be brought. Thus, the tyre service life is shortened.
In order to extend the tyre service life, ZPMC developed gantry turning hydraulic jacking device. When the gantry is turning, the jacking device will automatically jack up the whole RTG. The tyre abrasion is then reduced, and the service life is extended (by estimation at least one time of service life is extended).
6. Gantry Wheel Brake
The traditional RTG’s gantry brake is installed on the gantry driving motor shaft. When an emergency-stop occurs, the big force will be happened on the whole driving system (this is the main reason of the chain breakage).
ZPMC emulated automobile and installed wheel brakes on RTG. When the RTG is braking, the wheel brake consumes the majority of the energy, and then the high speed shaft brakes again. The whole gantry driving system has much lower impact, and the service life can be extended.
7. RTG’s Tyre Automatic Pressure Measuring Device
The insufficient tyre pressure is one of the problems that causes the tyre’s low service life. ZPMC studied and found that the majority of currently operating RTGs were existing insufficient tyre pressure. It is inconvenient to check the tyre pressure. Therefore, ZPMC developed a set of tyre automatic pressure measuring alarm device to remind operators at any time when any tyre has insufficient pressure in order to avoid the tyre running with insufficient pressure. The accident caused by tyre damage while RTG is operating can also be avoided.
8．Double 20ft RTG
The majority of RTGs in the world at present have lifting capacity of 40T as only one 20ft or 40ft container is hoisted. However, the quayside container crane can hoist two 20ft containers at one time, the operation of container crane and RTG can not match each other, and the handling efficiency is seriously affected.
In 2002, ZPMC developed the double 20ft RTG which can hoist two 20ft containers with lifting capacity of 60T. After trial operation for 2 years, the performance is good, and the yard handling efficiency is increased.
9. RTG With High Hoisting Height and Equipped with Elevator
As for such RTG with stacking height of 7 containers and the hoisting height of 24m, one small elevator will be equipped to reduce operators’ fatigue and ensure safety. Such small elevator can only hold two persons, and is provided with reliable safety device.
10. RTG with 16 Wheels
Along with continuous increase of RTG’s hoisting capacity and hoisting height, the RTG’s wheel load is keeping bigger (the maximum wheel load for ACT project in Hong Kong is 50T). ZPMC developed 16 wheel RTG with 8 driving wheels and 4 driving wheels respectively. The 16 wheel RTG has broadened the applications of RTG with
high hoisting height and handling of two containers (60T). Thus, the terminal productivity and utilization of the yard can be increased.
1.2 New Words and Expressions
1.ZPMC ZHENHUA PORT MACHINERY CO.,LTD 振华港机
2.Rubbery tyred gantry(RTG) 场地轮胎式集装箱起重机（轮
胎吊）
3.delivery 交货，递交
4.reeve 提升
5.sway－damping 摇摆－衰减
6.anti－sway 防摇
7.bi—directional 双向的
8.modulization 模块化
9.principal parameters 基本参数
10.spreader 吊具
11.trolley 小车
12.skew歪斜，回转
13.micro-movement 微动
14.instantaneous 即刻地
15.peak 山峰，顶峰
16.diesel engine 柴油机
17.super capacitor 超级电容
18.farad 法拉(电容量单位)
https://www.360docs.net/doc/8916370397.html,pensate (工)补偿，赔偿 (生)酬报
20.GPS (Global Positioning System) 全球定位系统
21.simulating rail 虚拟轨道（铁轨）
22.triangle 三倍的
23.semi-automation 半自动化
24.cord fabric 绳索结构
25.hydraulic jacking 〔液力；起重〕千斤顶
26.impact 加强，系紧，固定
27.hoist n. 起重机，卷扬机，升降机v. (用滑轮等）升起，举起
28.utilization 利用,效用,使用