Infusing unit for a venturi-type bubble-forming apparatus

A bubble-forming apparatus including a beverage container, a venturi-tube type inlet pipe unit having a main pipe section with a truncated conical lower end portion which decreases downward in diameter and which is adapted to permit passage of a high-pressured gas therethrough, a discharge pipe unit, a fixed infusing casing disposed in said container between said inlet pipe unit and said discharge pipe unit and having an interior chamber defined within said casing in communication with said inlet pipe unit and said discharge pipe unit, and a branch pipe which is communicated with the interior chamber of said infusing casing at a position between said inlet pipe unit and said discharge pipe unit and which is adapted to draw a liquid from the beverage container into said chamber so as to mix said liquid with said gas in said infusing casing, thereby forming a combined fluid which is discharged from said casing through said discharge pipe unit, wherein the improvement comprises:

• said infusing casing being generally tubular and having a large-diameter upper section within which said main pipe section of said inlet pipe unit is press-fitted in such a manner that a fluid-tight seal is established between said large-diameter upper section and said main pipe section, and a small-diameter lower section located coaxially within said discharge pipe unit, said truncated conical lower end portion of said inlet pipe unit being located within said large-diameter upper section and ranging from 1.0 mm to 1.7 mm in inner diameter, said casing further having an integral tubular section which extends radially and outwardly from said lower section of said casing and which is press-fitted into said branch pipe so as to draw said liquid into said casing, said integral tubular section ranging from 2.5 mm to 3.5 mm in inner diameter, said lower section of said casing having a tapered upper portion which decreases gradually downward in inner diameter, and a straight lower portion which extends integrally and downwardly from said tapered upper portion and which has an axial length ranging from 2.0 mm to 4.0 mm and an inner diameter ranging from 2.0 mm to 3.0 mm.