Whats the difference/benefit of these style of regulators?

[sontek]

I have 2 regulators, one is short and stocky and the other is tall and swivels on top. I'm just wondering what the difference/benefits of these designs are... The short one is older.

Here are pictures of the 2:

 

[mike_s]

maybe someone else has a better answer... but maybe one is diaphram and the other is piston?

 

[herman]

The one on top is a flow thru piston design and the lower one is a diaphram design. From a performance standpoint they are pretty much the same as far as the end user is concerned. The FTP will likely flow a little more gas at full flow but that is much more than any 2 divers can use so it's a mute point. The rest are creature features, the swivel on one may....or maynot depending on your preference provide better hose placement. Both appear to be Scubapros in which case they are both good quality regulators that should be easy to get serviced.....bottom line, pick the one you like because both will do nicely. The choice of the second stage to go with them is much more important.....and pretty much any second stage with work with either of these 2 regs.

 

[halocline]

Herman pretty much nailed it. The bottom one look like a MK16 or MK11, the top one looks like a MK5 clone, not an actual SP reg.

 

[Nemrod]

The top one is a clone MkV, a copy of the Scubapro MkV. These are a high performance flow through design. The swivel turret is both a strength and a weakness. It can fail if it has a brass swivel nut, most have been converted to a much stronger stainless nut, the swivel allows easy positioning of the hoses. As well, the swivel action, the O-ring there needs a yearly change if the reg gets dived a lot, at least mine do. I prefer the clone MkV units myself and have several, great units:

Never mind the camera still life, that reg is a Scubapro R109 with a MkV clone first and HD Scubapro yoke. A mixture of Scubapro and Tekna parts and whatever I had laying about.

N

 

[Hank658]

Thanks for the pic N., now I have port envy!!

 

[Nemrod]

Thanks for the pic N., now I have port envy!!

Sorry for showing off , this is the time of year I build everything up for the coming season, so I can grab my stuff and DIVE, DIVE, DIVE and not work, work, work on broken stuff. N

 

[John C. Ratliff]

I have 2 regulators, one is short and stocky and the other is tall and swivels on top. I'm just wondering what the difference/benefits of these designs are... The short one is older.

Here are pictures of the 2:

If you'll take a look at the top regulator, the Scubapro Mk5 (or look-alike), you'll see a LP port on the top. If you'll look at Nemrod's regulator, you don't see that port. Years ago, the U.S. Navy did some testing on regulators, and came up with a clear winner, and it was a Scubapro. But it wasn't the Mk 5. It was their lower-priced flow-through piston with only one port, right off the top of the first stage. The reason was that the air did not have to make a 90 degree turn--it flowed straight through the piston and into the hose without disturbance. Scubapro was a bit embarrassed, and modified their Mk 5 first stage to have that port on the top. So if you are diving extremely deep, or in high current and want the best performance, put your main regulator on that top port.

I haven't seen data on piston verses diaphragm designs, but because of turbulance inherent in the diaphragm design, the flow-through piston will probably out-perform the diaphragm unless there is significant volume of air in the space around the diaphragm to smooth out the flow.

The same goes for the 90 degree turn that is on Nemrod's second stage. This has a lot of convenience pluses, but from a pure performance standpoint, the 90 degree turn will detract from the regulator's performance. I have an industrial ventilation book which shows that from a design standpoint, the longer and smoother the curve, the better the performance of the system. It shows a 90 degree bend as a condition to avoid for an elbow.

SeaRat

 

[Nemrod]

I have one with the port on top also, however, the Tekna/Oceanic/various clone MkVs have a larger internal area and more relief to the ports than the original Scubapro multi port turret or the earlier two port swivel. I imagine under an all out performance test the top port would still flow more air.

Yes, I believe that piston regs with the large flow through piston like the MKV clones will out perform a diaphragm first--but---they all flow way more air at sport depths or even tech depths than needed so not sure it matters in a practical sense.

N

 

[sontek]

The top one is a oceanic alpha px3