Fig. 7.7 Construction of a cooling system
Fig. 7.8 Construction of the Stirling cooler
The working fluid is the helium of a non condensing gas. When each the piston moves, the working fluid repeats the following changes; isothermal compression (heat rejection), isovolumetric cooling, isothermal expansion (heat absorption) and isovolumetric heating. When the working fluid is changing at isothermal expansion, it absorbs heat from the outside on the heat absorber shown as the cold head in Fig. 7.7. On the other hand, when it is changing at isothermal compression, it rejects heat to the outside on the heat rejecter. This cooler operates as the refrigerator which works in the reverse Stirling cycle. The regenerator exchanges heat between the low temperature side and the high temperature side with keeping both temperatures at the isovolumetric change. This Stirling cooler can work in wide temperatures ranging from -260℃ of the ultra-low temperature to the room temperature in the field of refrigeration. It is low vibration and low noise. As its refrigerating capacity can change proportionally to the pressure of the refrigerant gas filled in it, this cooler can be applied to a wide range and multiple-use cooling system from an ultra-low temperature refrigerator to a refrigerator for home use.
This Ultra-Low Temperature Stirling Refrigeration Unit “STU-30K,” which is produced at this time, operates by AC 3φ200V of the electric power source. The cold head temperature is from -180℃ to -50℃. The maximum refrigerating capacity is only 500W. This unit is a small typed refrigerator. If the unit scales up and has a large capacity in future, it will become to apply to the ships. It will attract a great deal of attention as the very high efficient refrigerator because the coefficient of performance of the reverse Stirling cycle is almost the same as one of the reverse Carnot cycle.
References
1) Ishikawajima-Harima Engineering Review, Vol. 38 No. 2 (1998) pp. 135
2) Mitsubishi Juko Giho, Vol. 35 No. 3 (1998.5) pp. 182
3) Ishikawajima-Harima Engineering Review, Vol. 38 No. 6 (1998) pp. 392
4) Mitsubishi Juko Giho, Vol. 35 No. 2 (1998.3) pp. 120
5) Mitsubishi Juko Giho, Vol. 35 No. 2 (1998.3) pp. 88
6) Refrigeration, vol. 73 No. 846 (1998.4) pp. 64
7) Sekiya-Komatubara-Kawanishi, The 2nd Symposium on Stirling Cycle, No. 98-19, (1998. 10) pp. 129
[Nobukazu SHIMADA]
8. Deck Machinery
In the section of deck machinery in 1998, only the following development of the container crane was carried out. The further detail is described as follows.
Development of Rubber Tired Transfer Crane (RTG)1)
Recently, container terminals are becoming increasingly automated and taking other labor saving measure. Kawasaki Heavy Industries, Ltd. has been in the vanguard of terminal automation, based largely around continuous improvements to container crane technology. Using these technologies, the Rubber Tired Transfer Crane (RTG) has been developed as the core of a container yard system and makes use of new concepts to meet the functions necessary for terminal automation. The general configuration of the RTG is shown in Fig. 8.1.
As the RTG drive 4 wheels mounted at both ends of the front and rear axles, it can keep straight on excellently. The tires have a long life. The RTG has the automatic straight traveling system, too. This system is to move it automatically with surveying the magnets laid under the ground by the magnetic sensors.
