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World's First Variable-Cylinder Dual-Rotary Compressor

Fully utilizing precision processing technology, Toshiba was the first company in Japan to independently develop such compressors, leading the world in inverter technology and establishing the trend of compressors for air-conditioners.

World's First Variable-Cylinder Dual-Rotary Compressor

General Electric Company (GE) in the U.S. commercialized a rotary compressor for air-conditioners in the early 1950s. In Japan, our company independently proceeded with the development of a rotary compressor for air-conditioners from 1967 onward, using GE's model 30 series as a reference. This development work became a company-wide project and finally, in 1969, we developed Japan's first rotary compressor for air-conditioners using our own technology. By the development of made high-speed and high precision processing on the order of micrometers, rotary compressors got high efficiency, structural simplicity, and low cost. Today, rotary compressors have been adopted in innumerable residential air conditioners throughout the world, and it would be no exaggeration to say that our company played the leading role in the history of rotary compressors.

Subsequently, accompanying the increased awareness of energy saving due to the oil crisis in 1973, variable speed compressors, which can control capacity, were needed with a function allowing variable capacity control instead of the conventional type in which the room temperature was controlled only by on/off operation. At that time, compressors, can not be operated such a wide range of rotation speeds from low to high, and equipping an inverter with an air conditioner was considered to be difficult due to high cost and bulky dimensions.

Once again, however, we overcame the obstacles and developed an AC inverter-driven single-rotary compressor for residential air-conditioners that was capable of handling variable speeds. By reduction in the size and weight of the inverter, we released the world's first inverter type rotary air conditioner for home use in 1981. This attracted a tremendous response, and in recognition of the revolutionary role of this product in the history of airconditioner technology, Toshiba received the 16th Contribution Prize of the Ichimura Industrial Awards from the New Technology Development Foundation in 1984. We then went on to develop an AC inverter-driven twinrotary compressor for home use in 1988. The twin-rotary compressor not only made it possible to significantly improve cooling and heating capacity, but also achieved lower vibration and quieter operation. Next we developed a DC inverter-driven twin-rotary compressor in 1993, which achieved such a high level of energy saving that the electricity bill was halved compared with conventional models. This development was made possible by driving the compressor with a newly developed DC motor instead of the AC motor used up to that time. Then, in 2004, we developed the world's first variable-cylinder dual-rotary compressor, which realized super energy saving. For this achievement, Toshiba was awarded the 2nd New JSPMI Prize by the Japan Society for the Promotion of Machine Industry in 2005.

In order to maintain a constant temperature in steady operation, the conventional twin-rotary compressors still wasted electricity by on and off operation, even with inverter control. The introduction of a dual variable-cylinder configuration can be allowed steady operation with only one cylinder off to maintain a constant temperature, realizing the ultimate super-energy-saving operation. The energy-saving effect is particularly conspicuous in presentday detached houses, condominiums, and offices, which have a highly airtight structure. Our high-efficiency variable-cylinder rotary compressor has continued to evolve, and was awarded the JSME Medal for New Technology by the Japan Society of Mechanical Engineers in 2012.

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