Patent ID: 7621268

Claim:
An improved snorkel used as a swimming aid, of the type with decreased dead space which facilitates free diving having: a mouthpiece; an inhalation tube of a first cross-sectional area, connected to the mouthpiece, and extending upwardly of the mouthpiece a first distance, the inhalation tube terminating in a float valve; a first check valve positioned between the inhalation tube and the mouthpiece, the first check valve arranged to allow air to be drawn through the float valve to the mouthpiece but prevents air flowing from the mouthpiece through the first check valve to the inhalation tube; an exhalation tube of a second cross-sectional area, the exhalation tube extending upwardly of the mouthpiece along and joined to the inhalation tube a second distance which is less than the first distance, the exhalation tube being terminated by an exhalation valve; a second check valve positioned between the exhalation tube and the mouthpiece, the second check valve arranged to allow air to be exhausted from the mouthpiece through the exhalation tube but prevents air from being drawn through the exhalation tube to the mouthpiece; and a purge valve which incorporates a check valve positioned below the mouthpiece; wherein the improvement comprising: wherein the exhalation tube of the second cross-sectional area being smaller than the first cross-sectional area of the inhalation tube; wherein the purge valve which incorporates the check valve positioned below the mouthpiece is positioned before the second check valve; wherein the exhalation valve is a gravity operated valve which prevents water from entering when the exhalation valve is above a water surface, but opens when the exhalation valve is below the water surface.