PROBLEM TO BE SOLVED: To prevent unexpected inflow of liquid in a liquid container such as an injector into a patient body.SOLUTION: An anti-free flow valve interposed between a liquid container Fc and a liquid passage Sc includes: a connection path Cc connecting the liquid container Fc and the liquid passage Sc valve bodies Vp, Vv, Vcp, and Vvp opening/closing the connection path Cc and valve body energization means for energizing the valve bodies Vp, Vv, Vcp, and Vvp by closing the connection path Cc even when pressure in one of the liquid container Fc and the liquid passage Sc is higher than pressure in the other side in the a case where a pressure difference between that in the liquid container Fc and that in the liquid passage Sc is less than a specified quantity, so as to block flow of liquid from a side with high pressure to the other side, and by opening the connection path Cc even when pressure in one of the liquid container Fc and the liquid passage Sc is higher than pressure in the other side in a case where a pressure difference between that in the liquid container Fc and that in the liquid passage Sc is a specified quantity or more, so as to allow flow of liquid from a side with high pressure to the other side.SELECTED DRAWING: Figure 1-1COPYRIGHT: (C)2017,JPO&INPIT【課題】注射器等の液体容器内の液体の、患者体内への不測の流入を防止する。【解決手段】液体容器Fcと液体通路Scとの間に介装されるアンチフリーフローバルブにおいて、液体容器Fcと液体通路Scとを接続する接続路Ccと、接続路Ccを開閉する弁体Vp,Vv,Vcp,Vvpと、液体容器Fc内と液体通路Sc内との圧力差が所定量未満の場合は液体容器Fc内と液体通路Sc内との何れの側の圧力が他方の側の圧力より高い場合でも接続路Ccを閉止してその圧力の高い側から他方の側への液体の通流を阻止し、液体容器Fc内と液体通路Sc内との圧力差が所定量以上の場合は液体容器Fc内と液体通路Sc内との何れの側の圧力が他方の側の圧力より高い場合でも接続路Ccを開放してその圧力の高い側から他方の側への液体の通流を許容するように弁体Vp,Vv,Vcp,Vvpを付勢する弁体付勢手段と、を具える。【選択図】図1-1
