Suction device (6)
I believe the answer is:
siphon
'suction device' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for siphon that I've seen before include "Soda dispenser" , "Drawing device" , "On ship (anag)" , "Draw off (liquid) by pipe" , "Bottle from which a liquid is forced by pressure of gas" .)