Pneumatically Balanced ValveThe pneumatically balanced second stage reduces breathing resistance to near zero with a balanced valve seat designed to respond to the slightest inhalation.
A pneumatically balanced second stage actually has (or can have) the same initial crack opening effort as a mechanically balanced, but the spring force of a pneumatically balanced second stage is lighter so it’s spring rate is also lower.
Therefore the force required to open the valve farther as flow increases is less than that required for a mechanically balanced second stage with a higher rate spring. So the total effort to breathe the pneumatically balanced second stage is indeed less.
The spring force must be just enough to overcome the difference between downstream air pressure and upstream balance chamber pressure.
The downstream air travels through a hole in the poppet into the balance chamber and applies an “upstream” force just slightly less than the downstream force.
Diver Adjustable Inhalation EffortA simple twist of the adjustment knob enables complete control…
Set the inhalation requirement to near zero when you need ultimate performance, or tune it for greater resistance as conditions or preferences change.
Most downstream demand valve regulators are calibrated during manufacturing to a single, ‘middle of the road’ operation. Whether finning up current at 100+ feet or merely snorkeling out to the dive site, this factory adjustment may not be optimum for the wide variety of demands we place on our equipment.
FDX-10 Over-Balanced Diaphragm First StageForged from marine-grade brass, the FDX-10 features optimized air paths and angled hose ports for superior performance and comfort.
A sealed Balanced Diaphragm design, Enviro Kit and patented DVT (Dry Valve Technology) isolate all internal components from the environment. 2 high pressure and 4 low pressure ports allow convenient and comfortable hose routing.
The FDX-10 high performance over-balanced first stage provides progressively greater intermediate pressure as depth and gas density increases. The center “pads” that the diaphragms act against are different sizes so the working area of the outer environmental diaphragm is larger than the working area of the inner diaphragm. As depth increases, more pressure is applied to the larger surface area of the outer diaphragm than would be applied to the internal diaphragm. The result is superior gas delivery under the most extreme conditions.