I'm looking at the Delta4 with FDX-10 first stage as my new regulator for this season. However, I'm really not happy about Oceanic's DVT -- Dry Valve Technology.
My dealer received a cutaway cross-section of the DVT mechanism, which basically consists of a bullet-shaped piece of red plastic attached to a spring. Interesting concept, and will probably save a few people from having to replace the guts of their first stage. But I think there is a design flaw, and I'd love to hear feedback from someone better informed.
What I can't understand about this mechanism is why the "stopper" seats against the rather pointy-edged metal of the first stage (not represented well in the diagram, but you get the idea), rather than an o-ring. The plastic of the stopper is fairly hard, but in order for it to effectively stop water from entering the first stage, the spring has to exert some pressure, pushing the stopper into those metal points. Without a doubt, this plastic piece will begin to wear out over time.
The issue, however, is not the fact that the part will wear out. (Frankly, I don't care if it wears out, and would rather it was optional with purchase.) The issue is, if you look at the design, all the little scrapings that are bound to happen when the stopper seats against the metal have to go somewhere, and based on what I can see, that "somewhere" is "inside the first stage."
So a few things come to mind. First, are you going to be breathing these bits of plastic? What is the stopper made from?
Second, when this "erosion" process inevitably begins, will the fine bits of material within the first stage create an increased flash hazard with high FO2 / PO2?
Third, you won't be able to see the filter, and so if you get moisture or other contaminant from a cylinder, you won't have a good visual means to identify the problem.
Would love to hear from greater minds on this matter. Doug Krause, are you out there too?
-Andrew
My dealer received a cutaway cross-section of the DVT mechanism, which basically consists of a bullet-shaped piece of red plastic attached to a spring. Interesting concept, and will probably save a few people from having to replace the guts of their first stage. But I think there is a design flaw, and I'd love to hear feedback from someone better informed.
What I can't understand about this mechanism is why the "stopper" seats against the rather pointy-edged metal of the first stage (not represented well in the diagram, but you get the idea), rather than an o-ring. The plastic of the stopper is fairly hard, but in order for it to effectively stop water from entering the first stage, the spring has to exert some pressure, pushing the stopper into those metal points. Without a doubt, this plastic piece will begin to wear out over time.
The issue, however, is not the fact that the part will wear out. (Frankly, I don't care if it wears out, and would rather it was optional with purchase.) The issue is, if you look at the design, all the little scrapings that are bound to happen when the stopper seats against the metal have to go somewhere, and based on what I can see, that "somewhere" is "inside the first stage."
So a few things come to mind. First, are you going to be breathing these bits of plastic? What is the stopper made from?
Second, when this "erosion" process inevitably begins, will the fine bits of material within the first stage create an increased flash hazard with high FO2 / PO2?
Third, you won't be able to see the filter, and so if you get moisture or other contaminant from a cylinder, you won't have a good visual means to identify the problem.
Would love to hear from greater minds on this matter. Doug Krause, are you out there too?
-Andrew