If you could only keep one rebreather mouthpiece which would it be? The mouthpiece of a rebreather serves several purposes. Besides the obvious role of allowing the divers to breathe from the loop, the mouthpiece also directs the flow of gas around the loop. Utilizing simple one way valves or “mushroom valves”, the mouthpiece allows gas to enter from the inhale side of the loop as the diver inhales. The inhale mushroom valve then closes and seals the inhale side of the mouthpiece as the diver exhales, opening the exhale mushroom valve and allowing gas to pass from the mouthpiece into the exhale side of the loop. There are two categories of mouthpieces, dive/surface valves (DSVs) and bailout valves (BOVs).
The mouthpiece of a rebreather serves several purposes. Besides the obvious role of allowing the divers to breathe from the loop, the mouthpiece also directs the flow of gas around the loop. Utilizing simple one way valves or “mushroom valves”, the mouthpiece allows gas to enter from the inhale side of the loop as the diver inhales. The inhale mushroom valve then closes and seals the inhale side of the mouthpiece as the diver exhales, opening the exhale mushroom valve and allowing gas to pass from the mouthpiece into the exhale side of the loop. There are two categories of mouthpieces, dive/surface valves (DSVs) and bailout valves (BOVs).
DSVs: Simply allow the diver to switch from dive mode to surface mode, which opens and closes the mouthpiece to the ambient atmosphere. DSVs are simple, streamlined, and lightweight. However, they require the diver to remove the mouthpiece and switch to an offboard bailout regulator to access open circuit gas in case of an emergency.
BOVs: Also allow the user to open and close the loop to ambient atmosphere. However, when the mouthpiece is closed, it functions as an open circuit regulator. This allows immediate access to a known open circuit gas without requiring the diver to remove the mouthpiece. Incorporating an open circuits regulator into the mouthpiece makes BOVs more complex and slightly bulkier than a DSV, however.
The mouthpiece of a rebreather serves several purposes. Besides the obvious role of allowing the divers to breathe from the loop, the mouthpiece also directs the flow of gas around the loop. Utilizing simple one way valves or “mushroom valves”, the mouthpiece allows gas to enter from the inhale side of the loop as the diver inhales. The inhale mushroom valve then closes and seals the inhale side of the mouthpiece as the diver exhales, opening the exhale mushroom valve and allowing gas to pass from the mouthpiece into the exhale side of the loop. There are two categories of mouthpieces, dive/surface valves (DSVs) and bailout valves (BOVs).
DSVs: Simply allow the diver to switch from dive mode to surface mode, which opens and closes the mouthpiece to the ambient atmosphere. DSVs are simple, streamlined, and lightweight. However, they require the diver to remove the mouthpiece and switch to an offboard bailout regulator to access open circuit gas in case of an emergency.
BOVs: Also allow the user to open and close the loop to ambient atmosphere. However, when the mouthpiece is closed, it functions as an open circuit regulator. This allows immediate access to a known open circuit gas without requiring the diver to remove the mouthpiece. Incorporating an open circuits regulator into the mouthpiece makes BOVs more complex and slightly bulkier than a DSV, however.