Patent ID: 7077154

Claim:
Apparatus for controlling pressure of a gas in a system that depends on the pressure being produced by bubbling the gas through a liquid, said apparatus comprising a hollow vessel, a cap, and a positionable tube, said hollow vessel being arranged to have a predetermined amount of the liquid introduced therein, whereupon the surface of the liquid reaches a predetermined height in said vessel, said cap being located above the surface of the liquid in said vessel and including an opening through which said positionable tube extends, said positionable tube including a proximal portion arranged to be coupled to a source of the gas, whereupon the gas may flow into and through said positionable tube, said positionable tube including a distal portion which is linear and terminates at an outlet port through which the gas may exit to bubble up through the liquid when said outlet port is immersed in the liquid, said positionable tube and said cap being coupled together in such a manner that said linear distal portion of said positionable tube cooperates with said opening in said cap whereupon said outlet port of said positionable tube can be expeditiously located at any selected one of a plurality of predetermined, discrete distances below the surface of the liquid,but not at any intermediate positions between said discrete distances, and held in place at such selected discrete position against accidental displacement, at least one of said positionable tube and said cap including indicia thereon indicating the pressure of the gas in said system for each of said plurality of predetermined, discrete distances, said cap also including a vent opening.