This invention relates to an improved structure of safety infusion metering chamber, which comprises an infusion metering chamber, an upper cover, an upper infusion tube, a lower cover, a stop component, and a drip chamber, wherein the upper cover is provided with a dosing tube and an air discharging valve respectively used for dosing and discharging the air in the metering chamber. When adding liquid, the stop component is used to prevent the air in the infusion metering chamber from entering the drip chamber connected to the bottom part of the infusion metering chamber. The stop component is mainly composed of a stop shell and a weight member, wherein the stop shell has a side wall surface smaller than the inner wall surface of the infusion metering chamber. A stop member extended from the bottom part of the stop shell can block a liquid inlet on the lower cover and is fitted with the sealing rubber ring. Most importantly, the weight member is disposed to a recess at the center of the bottom part inside the stop shell, and an incline wall surface inclined toward the recess is utilized to roll the weight member into the recess again after being departed from the recess so as to maintain the stop component to be in horizontal state, thereby effectively avoiding the stop component from being stuck in the infusion metering chamber due to inclination or other reasons that may cause a failure in the prevention of the air in the infusion metering chamber entering the drip chamber connected to the bottom part of the infusion metering chamber.本發明係一種安全輸液計量筒結構改良,其主要由輸液計量筒、上蓋、上輸液管、下蓋、止擋組件及點滴筒組成,其中上蓋設有加藥管及空氣排出閥,分別用以加藥及排出計量筒內的空氣,加入液體時利用止擋組件可防止輸液計量筒內的空氣進入連接於輸液計量筒底部之點滴筒,其中止擋組件主要由止擋殼及重量件組成,其中止擋殼側壁面係小於該輸液計量筒內壁面,而止擋殼底部延伸出的止擋件可堵住下蓋上的進液口並與密封橡圈相貼合,重要的是重量件係設於止擋殼內部底面中央處的凹槽,且利用向凹槽傾斜之傾斜壁面讓重量件脫離凹槽後亦可再滾至凹槽中,以保持止擋組件處於水平的狀態,以有效避免止擋組件因傾斜卡在輸液計量筒內或其他原因而無法達到防止輸液計量筒內的空氣進入連接於輸液計量筒底部的點滴筒。20‧‧‧輸液計量筒206‧‧‧內壁面21‧‧‧上蓋22‧‧‧上輸液管2300‧‧‧進液口24‧‧‧止擋組件241‧‧‧止擋殼2416‧‧‧導斜邊25‧‧‧點滴筒26‧‧‧插針27‧‧‧密封橡圈29‧‧‧加藥管30‧‧‧空氣排出
