Sanden Corporation

Japan Electronic Control Systems Company, Limited

Syunji Komatsu

Kazumitsu Kobayashi

Masaru Kuribara

Yuji Nakajima

A refrigerant overcharge prevention system is applied to a refrigerant charging apparatus which has a refrigerant supply source and a refrigerant supply pipe connected to a refrigerant circuit of a cooling apparatus. The charging apparatus charges refrigerant into the refrigerant circuit while activating a compressor provided in the refrigerant circuit. The system comprises a refrigerant flow suppressing mechanism provided in the refrigerant supply pipe for preventing an excessive flow of refrigerant being charged, a refrigerant charge determining sensor provided in a high-pressure side path of the refrigerant circuit for determining whether the amount of charged refrigerant reaches a desired level by sensing a change of the state of refrigerant present in the refrigerant circuit, and a compressor deactivating circuit for deactivating the compressor in response to the determination of the refrigerant charge determining sensor. The refrigerant charge rate is appropriately suppressed by the refrigerant flow suppressing mechanism to prevent generation of an excessive amount of bubbles of refrigerant in the refrigerant circuit. Completion of a proper refrigerant charge can be precisely and easily detected by the refrigerant charge determining sensor.

Refrigerant overcharge prevention system

A refrigerator having a refrigerant circulating circuit for circulating a mixture of a refrigerant and a refrigerating machine oil. The refrigerator includes a compressor with a bypass circuit or a variable displacement compressor, a state detecting sensor for sensing the degree of separation of the refrigerant mixture, determining circuit for determining whether the detected degree of separation is in a two phase separation area, and a control unit for controlling the amount of the refrigerant passing through the bypass circuit or the displacement of the variable displacement compressor. When the refrigerant mixture enters into the two phase separation area, the amount of discharge or the displacement of the compressor is decreased. The temperature of refrigerant mixture is lowered accordingly and the phase changes from the two phase separation area. The refrigerating machine oil is maintained in a uniformly mixed state with the refrigerant and circulates with the refrigerant to the compressor. As a result, a lock up or breakage of the compressor is prevented.

Refrigerator with lubricant mixture sensor

An air conditioning system having a circuit for determining whether sufficient refrigerant is present in the system by detecting a phase state of the refrigerant. The circuit comprises a comparison circuit for comparing a detection signal of a state detecting sensor with a first reference value and a second reference value lower than the first reference value. An indication signal is output after the detection signal exceeds the first reference value until the detection signal is less than the second reference value. When the amount of refrigerant in the system is proper, even if the detection signal varies due to translucent lubricating oil in the refrigerant, the indication signal is continued to be output unless the detection signal drops below the second reference value. The amount of refrigerant in the refrigerant circuit can be accurately determined and maintained within a proper range. If the detection signal becomes less than the second reference value from, for example, leakage of refrigerant, the amount of refrigerant in the refrigerant circuit can also be accurately determined as insufficient.

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Isesaki, Japan

Syunji Komatsu