APPARATUS FOR ASEPTICALLY DISPENSING A MEASURED VOLUME OF LIQUID

Apparatus is disclosed for dispensing accurately measured volumes of liquid, such as parenteral solution. The dispensing apparatus includes a rigid measuring chamber initially filled with sterilized air for accurately measuring the amount of liquid be dispensed and a flexible chamber communicating with the measuring chamber for receiving the sterilized air displaced from the measuring chamber as liquid enters the measuring chamber and for returning the sterilized air as liquid is withdrawn from the measuring chamber. In one embodiment of the present invention, the volume of the flexible chamber when fully expanded is equal to the maximum calibrated volume of the measuring chamber, whereby the flow of liquid from the apparatus is terminated when the flexible chamber has completely collapsed. In another embodiment the measuring chamber is provided with a conventional cut-off valve in which case the flexible chamber is adapted to eliminate the need for introducing contaminating environmental air into the measuring chamber. To further control the amount of liquid dispensed, the flexible chamber may be segmented or may be connected with a metering syringe.