Abstract: A fluid conduit attached at one end to a container of fluid is provided at the other end with a fluid discharge opening through which fluid can be transferred into a receiving vessel. A slide valve on the exterior of the conduit is biased into a closed position, precluding any fluid flow from the conduit until the discharge opening is inside the receiving vessel. The slide valve coacts with the receiving vessel to open and permit fluid flow. An air vent tube within the conduit communicates with an air vent opening in the vicinity of the discharge opening. The air vent tube includes one or more capillary sections of reduced inner diameter relative that of the air vent tube. The air bent tube admits air into the container to facilitate fluid flow, while the capillary section limits the rate at which the air enters, thereby reducing the pressure of air in the container below ambient pressure when fluid flows from the conduit.