Scroll compressors in each of which a compression mechanism including an orbiting scroll and a fixed scroll is housed in a casing have been known to date. The compression mechanism includes a compression chamber formed by engaging the fixed scroll and the orbiting scroll with each other. As shown in Patent Document 1, some of such scroll compressors reduce separation between the orbiting scroll and the fixed scroll by utilizing a pressure rise in the compression chamber.
The scroll compressor shown in Patent Document 1 is connected to a refrigeration circuit of an air conditioning system. A compression mechanism of this scroll compressor has a suction port that is open at a suction position of the compression chamber, a discharge port that is open at a discharge position of the compression chamber, and an intermediate port that is open at an intermediate position between the suction position and the discharge position in the compression chamber. The suction port communicates with a low-pressure line of the refrigeration circuit, and the discharge port communicates with a high-pressure line of the refrigeration circuit.
This configuration can press an orbiting scroll against a fixed scroll by utilizing the pressure of a fluid introduced through the intermediate port from the compression chamber at the intermediate position into the back pressure space. In this manner, application of a pressing force to the orbiting scroll can reduce separation of the orbiting scroll from the fixed scroll.