Those grooves across the whole first stage body look quite different to the first photos. Are they purely aesthetic, or do they have a purpose?
I assume they put them there to allow the regulator to exchange heat, or rather, cold, with the environment. The gas in the first stage cools down considerably upon expansion, potentially making the regulator prone to freezing.
The way the grooves are cut may not be the wisest choice from an engineering standpoint, but they are certainly cost-effective. A better design would have been stacked fins cut into the regulator body, but that would add much more complexity to manufacturing. I believe this strikes a good balance to keep costs low.
I'm not entirely sure if the groove cut into the cap of the environmental seal makes much sense, but it certainly won't hurt. In a design like this, external freezing is of fairly little concern, as no moving parts besides the environmental diaphragm are exposed to water. Yes, this diaphragm can potentially freeze up, but conditions would have to be extremely harsh for this to occur and have a tangible effect. The point where temperature drops so much is fairly far from that outer diaphragm.
A far bigger concern,often overlooked, is the formation of ice droplets around the orifice and seat of the first stage. This can happen when moist air is present in the system, such as from a malfunctioning compressor. Such a ice droplet can be wedged between the seat and orifice, leading to a slight free-flow, which starts a chain reaction. I suppose what I’m saying is that in future iterations, they may want to consider adding more grooves or fins to the body of the first stage, particularly near the area where the pressure drop occurs.
I know I disagree with many people on this, but I believe stainless steel is not the best choice for regulator design, especially for a first stage. There is very little that beats brass in terms of mechanical properties. Leaving aside oxygen compatibility issues, since this regulator is not marketed for oxygen use, brass is far superior in terms of thermal conductivity. On average,
brass (~99 W/mK) should be able to exchange heat about six times better than
SS316 (~17 W/mK), if not more.
Still, it's an interesting project, especially at that price point, and I’m sure it will make many people happy.
