Second stage scuba diving regulator

DETAILED DESCRIPTION In the present invention, when the second stage regulator thereof is unpressurized, such as in periods of storage or non-use, the poppet assembly has little or no force applied to it to press it against the sharp edge orifice.
During use, as soon as the interior of the regulator is pressurized, the anti-set poppet operates by using incoming air pressure from the first stage to move the poppet assembly forward to its working position to make contact with the sharp orifice.
In this manner, the sharp orifice only makes contact with the rubber seat during actual use.
This eliminates the deep impressions left by the orifice during periods of non-use.
A light or reduced force may remain on the poppet to keep it in the proximity of or just touching the orifice when the regulator chamber is unpressurized.
A scuba regulator with such an anti-set feature will have a longer service life and a drastically improved performance consistency.
Once the regulator has been pressurized, a spring adjustment knob can be externally rotated at a threaded connection of the regulator.
As the spring adjustment knob is rotated in or out, the load height of a balance chamber spring is varied.
If the spring is shortened, the cracking effort in the regulator is increased due to the higher spring load.
If the knob is retracted, that is, if the spring is lengthened, the cracking effort is decreased due to the lower spring rate.
The spring adjustment knob is a means to limit travel of the balance chamber within the regulator and to control the spring load by manually rotating the adjustment in or out to increase or decrease the inhalation cracking force, respectively.
OBJECTS OF THE INVENTION It is therefore a principal object of the present invention to provide an improved second stage regulator for scuba diving, the regulator having both an anti-set poppet and an external cracking-effort-control adjustment to permit the diver to vary the cracking effort manually during the dive.
It is an additional object of the present invention to provide an improved second stage regulator for scuba diving having a balanced linear flow demand valve with a pneumatically activated balanced poppet wherein a soft elastomeric seal engages a sharp-edge orifice only when the interior chamber of the regulator is pressurized and relaxes the seal from the orifice edge when the interior chamber of the regulator is unpressurized