MK5 = Mk1 + turret.

[Couv]

I was just perusing the files at the ScubaPro Museum http://www.scubaproregulatormuseum.org/ and realized that the MK5 is the same regulator as the original MK1 with a swivel turret attached. Same body, piston etc.

c

 

[Luis H]

Actually it is the same as the Mk-1 that was around during the late 60’s and must of the 70’s, not the original Mk-1 (during the mid 60's that regulator was only ofered with the 108 second stage, later it was ofered with the 109). Look at the regulator on right the picture below.

The very original Mk-1 they were recalled and there are very rare. It is very hard to find one.
Look at the regulator on the left.

It was a flow by balanced piston first stage, very unique.

Take a look at this link:
Read Ovalis post.
Vintage Double Hose • View topic - Scubpro MK I/109 (Model 101) restored


Here are some pictures from the link:

The pictures are from Ovalis.

 

[John C. Ratliff]

Very interesting Luis; I learned something new. It looks like this original Mark I was a piston which was "acting" like a diaphragm regulator in its design. I say that because the later idea of a balanced piston was to allow the air a straight pathway out to the LP outlet through the piston. This original Mark I uses the same type of movement to allow the air past the pin, and out the LP port through a common space. Was there any published flow data? Also, I note the internal nut instead of the screw on the drawing for securing the regulator to the tank--this is a holdover from the Healthways days...interesting. Could it be that this regulator is the last actual Healthways design?

SeaRat

 

[redacted]

Was this the birth of the Scubapro coaxial valve?

 

[Luis H]

It is just another type of balanced piston pressure reduction valve. This regulator was around, probably for less than a year in the early 60’s (probably around 1964 maybe a bit earlier).

When I think of the coaxial valve I think of the Air 1 and the D series second stages demand valve. Is that what you are referring about?
Those came out after the Pilot, in the very late 70’s (around 1979). I don’t think of that mechanism as a pneumatic piston, it is just a balanced valve.



There are many ways of accomplishing similar functions. There are many ways of making a balanced valve. It just happen than in the Scuba industry they all copy each other (especially now a day). It may be in part due to the liability from doing something different or just not wanting to take the risk of not being accepted by the customers (because it is different), but since the 70’s most regulators just look like each other.

It the hydraulic industries and other pneumatic industries there are many different types of control valves used to control fluid flow, and many different designs to accomplish the same functions. The Scuba industry uses just a few simple examples.


Last night I did a regulator clinic for our Scuba club here in Maine. In less than three hours I was able to cover the mechanisms and workings of most of the regulator types build now a day. With a few exceptions (like the newer Poseidon regulators) most second stages in production today can be placed into two types of demand valves and the first stages into three types of pressure reducing valves. And within their type they are all just copies of each other.


IMHO back in the 70’s (some started in the 60’s) there was a bit of an explosion in innovative designs in the Scuba industry (not just regulators, but in all the equipment). Some designs have become popular and the rest just disappeared. It just seem that companies like Scubapro, Dacor, Farallon, and even to a lesser degree US Divers, etc. were willing to take a chance in new designs. Many failed in the market, some deserving the failure some maybe just poor marketing. But, since then Scuba equipment design just seems kind of boring. IMO, it just seems that the largest risk Scuba companies are willing to take is in the use of wild colors and cosmetic styles.