Hitachi, Ltd.

Kazuo Yoshioka

Kensaku Oguni

Takao Senshu

Akira Atsumi

Hirokiyo Terada

Takashi Kato

Tomio Yoshikawa

Shigeaki Kuroda

Keiji Sato

A refrigeration system suitable for use in an air conditioner has a main refrigerant circuit including a compressor, a condenser, a first pressure reducer, a gas-liquid separator, a second pressure reducer and an evaporator connected in series to form a closed loop, and a gas injection passage providing a communication between the gaseous phase part of the gas-liquid separator and a compression chamber of the compressor. A stop valve is disposed in the inlet and outlet pipes of the gas-liquid separator, and a bypass passage is provided for connecting directly the outlet pipe of the condenser to the inlet pipe of the evaporator to bypass the gas-liquid separator. The stop valve is adapted to be controlled such that, when the gas injection to the compressor through the gas injection passage is not conducted, the refrigerant flows through the bypass passage bypassing the gas-liquid separator, while the gas-liquid separator functions as a receiver for adjusting the amount of refrigerant circulated in the main refrigerant circuit.

Refrigeration system

In an air conditioner separated into an indoor unit and an outdoor unit, a control circuit comprises a three-phase power source connected in common to the indoor and outdoor units, and a signal line led out from two phases of the power source. A contact of an electromagnetic relay energizing a compressor of the air conditioner is connected on the portion of the signal line in the indoor unit in series with a current sensor sensing the current flowing through the signal line, and a contact of a protective relay protecting the compressor is connected on the portion of the signal line in the outdoor unit in series with the electromagnetic relay. A first controller is disposed in the indoor unit for controlling on-off of the relay contact of the electromagnetic relay, and a second controller is disposed in the outdoor unit for energizing the protective relay contact thereby controlling on-off of the compressor.

Control circuit for air conditioner

A refrigeration apparatus has a refrigerant circuit which is constituted by a compressor, a condenser, a first pressure reducer, a gas-liquid separator, a second pressure reducer and an evaporator connected to one another in series. The refrigeration apparatus also has a gas injection line connected between a gaseous phase portion of the gas-liquid separator and a compression chamber of the compressor. The improvement comprises a liquid refrigerant extracting passage providing a communication between a portion of the gas-liquid separator at a predetermined level and a portion of the low-pressure side of the refrigerant circuit. With this arrangement, it is possible to stabilize the level of the liquid refrigerant in the gas-liquid separator.

Refrigeration apparatus

A refrigerating apparatus including a refrigerant circuit constituted by a compressor, a condenser, a first expansion device, a gas-liquid separator, a second expansion device and an evaporator which are successively connected. An injection path interconnects an upper part of the gas-liquid separator and a cylinder of the compressor during the compression stroke thereof. An auxiliary path is formed by connecting a solenoid valve closed in the normal operation and an auxiliary expansion device, with the auxiliary path being provided between the gas-liquid separator and the evaporator so as to be parallel to the second expansion device, and connected to the gas-liquid separator at a position higher than the connecting position of the second expansion device to the gas-liquid separator. The solenoid valve is opened when the load on the refrigerating apparatus increases. A main flow path resistance member may be provided in the injection path, and a further path formed by connecting an injection solenoid valve for injection, open during the normal operation and an auxiliary flow path resistance member together with the further path being connected in parallel to the main flow path resistance member. The injection solenoid valve is closed when the load on the refrigerating apparatus increases.

Growing community of inventors

Shimizu, Japan

Kazuo Yoshioka