Capillary fluid switch with asymmetric bubble chamber

Abstract

A switching device for controlling fluid motion. The device includes a capillary filled with a first fluid into which a wall-confined bubble of a second fluid is introduced to achieve a first switching event. Capillary geometry and wetting properties provide a pressure-related asymmetric energy potential distribution for controlling the flow of the bubble, and the device is called an asymmetric bubble chamber, or ABC. The bubble is initially trapped in an energy potential well, and upon increase of its volume moves from the well into a region of low energy potential to achieve a second switching event. The first switching event may be blocking of a fluid channel or reflection of an optical beam in an optical crosspoint switch, while the second switching event may be unblocking of a fluid channel or restoration of transmission of an optical beam. The increase in bubble volume between the first and second switching events can act as the stroke of a fluidic piston to pump a volume the first fluid within the capillary. The device can be employed to thermally degas a liquid. The use of large-magnitude geometry-related energy potentials permits rapid cyclical operation of the device in a manner resistant to mechanical shock.