Compressor and freezer

A compressor comprising:

• a fixed member that forms a compression chamber;
• and
• a movable member driven to rotate and change a volume of the compression chamber, the compressor being configured to suck a fluid into the compression chamber and compress the fluid,
• the fixed member including
• a discharge port penetrating the fixed member to lead the fluid out of the compression chamber, and
• a discharge valve configured to open and close the discharge port,
• the discharge valve including a valve body configured to
• close the discharge port by covering an outflow end of the discharge port, and
• open the discharge port by floating from the outflow end of the discharge port,
• an inflow end of the discharge port having a hydraulic diameter Di expressed by Di=4×(Ai/Li), where Ai is an area of the inflow end and Li is a circumferential length at the inflow end,
• an outlet flow path being formed between the outflow end of the discharge port and the valve body, the outlet flow path having
• a cross-sectional area Ao expressed by Ao=Lo×ho, and
• a hydraulic diameter Do expressed by Do=4×{Ao/(Lo+Lv)},
• where Lo is a circumferential length at the outflow end of the discharge port, ho is a reference lift amount of the valve body, and Lv is a circumferential length of a valve head,
• the valve head being a portion of the valve body in contact with the outflow end of the discharge port,
• a ratio Do/Di of the hydraulic diameter Do of the outlet flow path to the hydraulic diameter Di at the inflow end of the discharge port being 0.602 to 0.740.