a duct L-feed, a suction channel W, are interposed in the feed conduit L, the first valve 51 to open only flow path K in the case of air, than the first valve 51 of the flow path K interposed upstream side, as well as opening the flow path K with the air supply, at least during aspiration, and the second valve 52 to close the flow path K, and includes the, during the non-air and non-air intake and feed Due to pressure changes downstream of the first valve 51 in the duct L, the second valve 52 by the first valve 51 is linked to the fact that would open unexpected manner passage K is the flow path By closing the K, the second valve 52 prevents backflow of fluid R to the upstream side of the second valve 52.送気管路Lと、吸引管路Wと、送気管路Lに介装された、送気の際のみ流路Kを開く第1の弁51と、流路Kの第1の弁51よりも上流側に介装された、送気に伴い流路Kを開くとともに、少なくとも吸引の際、流路Kを閉じる第2の弁52と、を具備し、非送気及び非吸気の際、送気管路L内の第1の弁51よりも下流側の圧力変化に起因し、第1の弁51が不測的に流路Kを開いてしまうことに連動して第2の弁52は流路Kを閉じることにより、第2の弁52は、該第2の弁52よりも上流側への流体Rの逆流を防ぐ。
