FILTER DEVICE FOR REFRIGERANT CIRCULATION PIPE

PROBLEM TO BE SOLVED: To provide a filter device for a refrigerant circulation pipe where the replacement of the filter unit can be performed, with the device in operation. SOLUTION: This filter device is provided with a bypass passage 5 in parallel with a refrigerant main passage 4 within a refrigerant circulation pipe 2, within a filter housing 3 provided integrally in the middle of the refrigerant circulation pipe 2. A main valve seat 6 which partitions a refrigerant main passage 4 is provided on the refrigerant passage pipe 2d, between the first and second openings 5a and 5b of the bypass passage 5. The first and second openings 5a and 5b of the bypass passage 5 are provided with first and second valve seats 7 and 8. The main valve sheet 5 and the first and second valve seats 7 and 8 are provided with valves 9 and 10 which open and close so that the first and second valve seats may be closed when the main valve seat is open, and that the first and second valve seats 7 and 8 may be open when the main valve seat is closed. A filter unit 28A is set from a filter exchange port 29 to the filter set part 27 within the bypass passage 5, and the filter exchange port 29 is blocked with an opening and closing cover 30.