Refrigeration apparatus

A refrigeration apparatus, comprising:

• a plurality of refrigeration units each including a compressor, an oil separator, an oil return pipe that returns oil separated from a refrigerant by the oil separator to the compressor, and a heat dissipation heat exchanger that cools the refrigerant from which the oil has been separated;
• a pressure reducing valve connected to the heat dissipation heat exchangers of the plurality of refrigeration units;
• and
• an oil return control mechanism that controls a return destination of the oil separated by at least one of the oil separators of the plurality of refrigeration units, wherein
• the oil return control mechanism includes:
• an oil supply pipe that connects the oil return pipes of the plurality of refrigeration units to each other,
• a flow control mechanism disposed in the oil supply pipe, the flow control mechanism controlling a flowing condition of oil in the oil supply pipe, and
• ejection control mechanisms each disposed in a corresponding one of the oil return pipes at a position closer to a corresponding one of the oil separators than a connection position is, each of the ejection control mechanisms controlling an ejection condition of oil ejected from the corresponding oil separator, the connection position being a position where the corresponding oil return pipe connects to the oil supply pipe,
• wherein:
• the flow control mechanism includes a plurality of regulating mechanisms disposed in the oil supply pipe;
• each of the plurality of regulating mechanisms includes an oil supply valve and an oil supply check valve disposed in series;
• and
• the oil supply check valve is disposed so as to allow oil to flow only in one direction.

A refrigeration apparatus, comprising:

• a plurality of refrigeration units each including a compressor, an oil separator, an oil return pipe that returns oil separated from a refrigerant by the oil separator to the compressor, and a heat dissipation heat exchanger that cools the refrigerant from which the oil has been separated;
• a pressure reducing valve connected to the heat dissipation heat exchangers of the plurality of refrigeration units;
• and
• an oil return control mechanism that controls a return destination of the oil separated by at least one of the oil separators of the plurality of refrigeration units, wherein
• the oil return control mechanism includes:
• an oil supply pipe that connects the oil return pipes of the plurality of refrigeration units to each other,
• a flow control mechanism disposed in the oil supply pipe, the flow control mechanism controlling a flowing condition of oil in the oil supply pipe, and
• ejection control mechanisms each disposed in a corresponding one of the oil return pipes at a position closer to a corresponding one of the oil separators than a connection position is, each of the ejection control mechanisms controlling an ejection condition of oil ejected from the corresponding oil separator, the connection position being a position where the corresponding oil return pipe connects to the oil supply pipe,
• the refrigeration apparatus further comprises:
• a controller that controls the oil return control mechanism, wherein
• each of the ejection control mechanisms includes an ejection valve, and
• the controller performs:
• first control to circulate oil in each of the refrigeration units by closing all the oil supply valves and opening all the ejection valves, and
• second control to supply, into the compressor of a predetermined refrigeration unit among the plurality of refrigeration units, oil in other refrigeration unit among the plurality of refrigeration units by closing the ejection valve disposed in the oil return pipe of the predetermined refrigeration unit, and by opening the oil supply valve of a regulating mechanism that allows oil to flow to the predetermined refrigeration unit, the regulating mechanism being one of the plurality of regulating mechanisms in the oil supply pipe connected to the oil return pipe of the predetermined refrigeration unit.