Abstract: Apparatus is provided for use in delivering a container within a conduit from a first, raised location, to a second lower location with the conduit remaining substantially at atmospheric pressure. The container includes a descent-regulating member having an exterior configuration which closely approximates the interior configuration of the conduit thereby providing a braking effect on the container as it traverses the conduit from the upper to the lower location and causing the container to descend within the conduit at a substantially constant, controlled rate. The apparatus includes provision for inserting containers within the conduit at the first location and removing containers from the conduit at the second location without substantially changing the amount of fluid within the conduit between the first and second locations. In a preferred embodiment, the conduit is closed at the ends proximate both the first and second locations.