The device 8, wherein an inlet portion of said second flow channel extends between said inlet and said first end of said second flow channel, an outlet portion of the second flow channel extends between said outlet and said {HEAD ~ second end} of {TAIL ~ said second flow channel}, and said closing valve unit is positioned in both said inlet and outlet portions of said second flow channel 
The device 8 , wherein an inlet portion of said second flow channel extends between said inlet and said first end of said second flow channel , an outlet portion of the second flow channel extends between said outlet and said { HEAD ~ second end } of { TAIL ~ said second flow channel } , and said closing valve unit is positioned in both said inlet and outlet portions of said second flow channel
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