GB2300813A

GB2300813A - Snorkel with small diameter tube

Info

Publication number: GB2300813A
Application number: GB9509770A
Authority: GB
Inventors: Bernard James Andrew Quinn
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-05-15
Filing date: 1995-05-15
Publication date: 1996-11-20
Anticipated expiration: 2015-05-15
Also published as: GB2300813B; GB9509770D0

Abstract

The snorkel comprises a small diameter tube of 15 mm bore or less to minimise the volume of exhaled air re-ingested and to improve clearance of any accumulated water through the increased exhalation airspeed. To minimise the pressure drop to the user's lungs, the inlet end of the snorkel is of ellipsoidal, bell-mouth section and the mouthpiece extends into the mouth so that the user can prevent ingestion of water by increased tooth clamping force and/or tongue blockage. The radius of the U-bend leading into the mouth section may be 3-5 times the diameter of the tube.

Description

DESCRIPTION This invention relates to a snorkel for use in water. A snorkel is essentially a tube through which one can breathe free air from above the surface, while ones mouth is immersed.

The problems often associated with snorkels include the inhalation of water and exhaled breath, and the difficulty of easily clearing the snorkel when it has ingested water (see for example GB 2 246 075 A and EP 0 377 919 Al).

This invention works in the opposite sense to the above referenced patents, and introduces a small diameter tube (less than 15 millimetre bore) specifically to minimise the volume of exhaled air re-ingested (to less than 2% of average adult lung capacity), and which at the same time improves clearance of any accumulated water through the increased exhalation airspeed and thence inertia of that water. An operational improvement is possible if the tube diameter is further reduced for those users with a smaller chest dimension.

The pressure drop to the users lungs is minimised, through the use of a bellmouth on the inlet end of the snorkel, and an improved mouthpiece, while the radius of the U bend into the mouth section should ideally be between 3 and 5 times the bore diameter of the tube. These will thus improve the safety margin on lung immersion depth (defined as 0.5metre in Diving Medicine, below which lung squeeze occurs).

The use of an ellipsoid bell mouth section ensures minimum loss but the invention is not limited to that alone, the increased losses due to other similar shapes requiring corresponding increases in tube diameter such that the total loss for the tube and its ends is controlled. It should be noted that exhalation speeds exceed inhalation, but the adaptation of a type of bell mouth to the mouth end of the tube to improve the mouth cavity losses, would provide an additional pressure loss advantage.

The usual style of mouthpiece would have two pegs or surfaces around which the teeth clamp leaving a tooth gap of about 4 or 5mm, but this is very difficult to seal with ones tongue, thus to prevent the ingestion of water. There is also a pressure loss into the mouth cavity. This invention therefore additionally extends the mouthpiece into the mouth cavity to ensure the user can easily block off the end. The mouthpiece either has pillars to support its height when clamped by the users teeth, positioned such that the tongue is prevented from entering too far and becoming seized within the diffuser, or as an alternative, the mouthpiece would have a flexible end such that increasing tooth clamping forces would close it off.

DESCRIPTION continued The invention thus takes advantage of a better understanding of the combined aerodynamics and mechanics associated with the snorkel and the user. It provides a simpler solution than those with double tubes or valves, and thus introduces a cost reduction.

The snorkel invented is thus more effective. It will improve the teaching of children to swim more confidently and safely, as well as being more enjoyable in use subsequently.

Claims

A A snorkel which extends the mouthpiece into the mouth such that the user can easily prevent the ingestion of water through either increased tooth clamping force or tongue blockage, or a combination of these, and which at the same time reduces mouth cavity pressure losses.
2 A snorkel which embodies a type of bell mouth at the air inlet end.
3 A snorkel comprising a small diameter tube of 15mm bore or less.
4 A snorkel as described in the above claims, which may be comprised of a number of component parts fitted, welded, glued or otherwise secured together in a leakfree manner.