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US 6,287,083 B1Granted
Compressed air production facility
AssigneeHitachi, Ltd.
InventorsMasakazu Hase, Masakazu Aoki, Hiroyuki Matsuda
Life of this patent
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AssigneeHitachi, Ltd.
InventorsMasakazu Hase, Masakazu Aoki, Hiroyuki Matsuda
Estimating the term…
A compressed air production facility includes at least one variable speed compressor and a plurality of constant speed compressor, which are connected in parallel with one another. The variable speed compressor and the plurality of constant speed compressors are capacitively controlled with the use of a pressure in an air reservoir into which discharge air from these compressor are led. Both upper limit pressure at which the variable speed compressor is turned into its load operation mode into its unload operation mode and a lower limit pressure at which the variable speed compressor is turned into its unload operation mode into its load operation mode are set between an upper limit change-over pressure at which all of the plurality of constant speed compressors are turned into their load operation into their unload operation and a lower limit change-over pressure at which all of the plurality of constant speed compressors are changed over from their unload operation into their load operation. With this arrangement, it is possible to provide a power consumption characteristic which is substantially proportional to an air consumption.
A compressed air production facility comprising at least one constant speed compressor which repeats load and unload operation at a predetermined speed under on-off control, a variable speed compressor driven by a motor incorporating an inverter, a common pipe line into which discharge air discharged from said constant speed compressor and discharge air discharged from said variable speed compressor are both led, a detecting means provided in said pipe line or air-reservoir, for detecting a pressure of the discharge air, and for controlling the discharged pressure to a predetermined set pressure with the use of said variable speed compressor, wherein the discharge pressure of said variable speed compressor on operation is controlled to said set pressure which falls between a discharge pressure of said constant speed compressor during said load operation and a discharge pressure of the constant speed compressor during the unload operation.
A compressed air production facility comprising at least one constant speed compressor which repeats load and unload operation at a predetermined speed under on-off control, a variable speed compressor driven by a motor incorporating an inverter, a common pipe line into which discharge air discharged from said constant speed compressor and discharge air discharged from said variable speed compressor are both led, and a control means for controlling a discharged pressure of a variable speed compressor to a predetermined set pressure with the use of said variable speed compressor so as to control the discharge pressure of said variable speed compressor to the set pressure which falls between a discharge pressure of said constant speed compressor during the load operation and a discharge pressure of said constant speed compressor during the unload operation, a detecting means for detecting the discharge pressure, a storage means for storing, as an unload operation pressure or a rest pressure of said constant speed compressor, a pressure at which the discharge pressure is turned from an increasing direction into a decreasing direction when air consumption being decreased, and for storing, as a load operation pressure or a start pressure of said constant speed compressor, a pressure at which the discharge pressure is turned from a decreasing direction into an increasing direction, and a means for setting the set pressure of said variable speed compressor to a value between said thus stored two pressures.
A compressed air production facility, comprising a plurality of constant speed compressors which repeat load operation and unload operation under on-off control, a variable speed compressor driven by a motor incorporating an inverter, a common pipe line through which discharge air discharged from said compressors is led, and a control means for carrying out such a control that said plurality of constant speed compressors are operated in accordance with an air consumption so as to successively operate and stop said plurality of the constant speed compressor, and said variable speed compressor is always operated.
Dependencies are inferred from the claim text.