COUPLING

PROBLEM TO BE SOLVED: To surely wash a filter since adaptors separated from each other are surely washed by providing the adaptors detachably fitted to couplers, and the filter detachably arranged between the coupler and the adaptor for eliminating foreign matters in a fluid. SOLUTION: For operating a next manufacturing work after raw materials 26 and water are supplied into a manufacturing vessel 27, both adaptors 12 are detached from couplers 11 together with feed hoses 30 and 31. Since the filter 13 is arranged between the coupler 11 and the adaptor 12, it is detached from the coupler 11 together with the adaptor 12. Since the couplers 11, the adaptors 12, the feed hoses 30, 31 are surely washed for next use, the filters 13 are simultaneously washed. Since the filters 13 are surely washed whenever feed of the raw materials 26 is completed, it is possible to provide a good product of an excellent quality not including the foreign matters.