Patent ID: 8011364

Claim:
A valve for use in an underwater breathing device, the valve configured to produce positive end-expiratory pressure in the airway of a user of the underwater breathing device, the valve comprising: a plate defining an exhalation port and at least one chamber port; an exhalation conduit connected to the exhalation port, a lower portion of the exhalation conduit being divided by a septum which divides the exhalation conduit and the exhalation port into a first exhalation conduit connected to a first exhalation port and a second exhalation conduit connected to a second exhalation port; and a flexible membrane that is sealable against a surface of the plate and is sized and positioned to be capable of sealing the first exhalation port and the second exhalation port, the flexible membrane comprising: a fully-sealed position in which the flexible membrane seals the first and second exhalation ports such that substantially no air nor water can flow through the first nor second exhalation ports; a partially-sealed position in which the flexible membrane seals the second exhalation port but does not seal the first exhalation port such that air and water can flow from the at least one chamber port through the first exhalation port and substantially no water can flow from the second exhalation conduit through the second exhalation port; and an unsealed position in which the flexible membrane does not seal the first and second exhalation ports such that air and water can flow from the at least one chamber port through the first and second exhalation ports.