LEAKAGE PREVENTION VALVE FOR MICROPUMP

PROBLEM TO BE SOLVED: To prevent leakage of discharge fluid from a pump to improve metering accuracy of discharge fluid.SOLUTION: A leakage prevention valve 40 for pump is connected to a discharge side of a pump 10 including a suction valve and a discharge valve respectively comprising check valves 24, 26, and prevents leakage of discharge fluid, the check valves communicating with a pump chamber 22 in normal and reverse directions. The leakage prevention valve includes: an expansible rubber film 46 in which a wall thickness part 46A formed integrally with a peripheral edge is held between split surfaces 44 of a valve case 42 and tension in a tension direction is imparted to a film surface 46B; a valve seat 54 opposite to one film surface of the rubber film 46 and configured to open/close by the rubber film 46; a pump inflow pressure chamber 48 configured to guide pump inflow pressure P1 to the other film surface of the rubber film 46 and press the rubber film 46 to the valve seat 54 side; and a valve side outflow passage 58 configured to guide pump discharge fluid to outside through the valve seat 54.SELECTED DRAWING: Figure 8 【課題】ポンプの吐出流体の漏出を防止し、吐出流体の計量精度を向上させる。【解決手段】ポンプ室２２に正逆方向に連通する逆止弁２４，２６からなる吸入弁および吐出弁を有するポンプ１０の吐出側に接続され、吐出流体の漏出を防ぐためのポンプ用漏出防止弁４０であって、周縁に一体に形成された肉厚部４６Aが弁ケース４２の割り面４４間に挟持され膜面４６Bに張り方向のテンションが付与された伸縮性ゴム膜４６と、このゴム膜４６の一方の膜面に対向しゴム膜４６によって開閉される弁座５４と、ゴム膜４６の他方の膜面にポンプ流入圧P1を導きゴム膜４６を弁座５４側に押圧するポンプ流入圧室４８と、弁座５４を介してポンプ吐出流体を外へ導く弁側流出路５８と、を備える。【選択図】図８