GB990583A - Liquid control device - Google Patents

Abstract

990,583. Intravenous administration. ABBOTT LABORATORIES. March 29, 1962 [March 29, 1961], No. 12163/62. Heading A5R. [Also in Division G3] A device for controlling the flow of liquid through an outlet from two independent sources comprises a passage through which fluid flows from a first inlet to the outlet and, in communication with said passage, a restricted passage leading from a secondary inlet. The arrangement is such that while liquid is flowing from the first inlet to the outlet, the flow resistance of the restricted passage, together with the internal pressure resulting from the first fluid, prevents any flow from the second inlet. This flow, however, commences as soon as the main flow stops. In a simple form of the device the main flow enters the body 20 through a pipe 22 and passes directly into the outlet pipe 23. The diameters of these pipes are so selected that a narrow space 25 exists between their telescoped end portions and the free end of this space is in communication with the secondary inlet 27. The presence of a column of liquid in the inlet and outlet tubes 22, 23 results in a positive pressure at the lower end of the space 25 and this, with its flow resistance, prevents liquid flowing from inlet 27. Stoppage of the main flow, however, allows it to pass to the outlet unimpeded. Similar arrangements are described in association with a drip chamber and also in a form in which it can be accommodated within a flexible container which holds the secondary liquid. A simple application for controlling the flow from two tanks is also described, with reference to Fig. 2 (not shown). In all cases the width of the constricted passage should preferably be between 0À005 and 0À019 inch and its length between 0À5 and 1À66 inches.