Nemrod Saturn Regulator

[davefest]

Hi All,

Newbie here, so please let me know if questions such as this are more welcome elsewhere.

Among some vintage stuff I accidentally bought (eBay...who woulda thought nobody else would bid?!) was an older regulator that I'm curious about. It's a Nemrod Saturn and is old enough to be chrome-shiny metal and pretty cool to look at (image below). I think it's around 1980 vintage. I assume some folks collect these, but does anyone know if using one is totally impractical? I.e., annual servicing, etc.

Here's an image ("borrowed" from http://www.scubacollector.de/html/singlehose_regs_nemrod.html):



Thanks in advance for any info!

Dave

 

[superstar]

I have several relic regulators I frequently use including an old Nemrod that works quite well. I skip annual service as I do everything myself. It looks as if you have a nice one, check the IP and adjust the cracking and use it.

 

[herman]

Looks like a flow through piston first and odds are the second is a common downsteam design. It's highly unlikely that you will find original parts but if my guess is right, you should be able to piece together a service kit. I looked in my Nemrod manual but don't have it listed.

 

[regulator bj]

Hello Davefest found some informantion which might prove usefull

 

[davefest]

superstar:

Sorry, I should have mentioned that I meant to describe myself as a "newbie" to diving as well as to scubaboard.com. I've completely torn down 2nd stage regulators and put them back together, but I don't know the lingo. Is IP the pressure between 1st 2nd stage regulators? Is cracking an adjustment to 1st stage?
​

regulator bj:

Thanks for the reply, but I'm not seeing the info or a link. Just a broken image.​

 

[herman]

The IP is the pressure that the first stage reduces tank pressure to and supplies to the second stage. Most regs are in the 135 to 145 PSI range but it is not really a critical value as long as it stays constant. By constant, I mean it locks up to a given value -135 say and stays that way without increasing and returns to that value after a breath is taken. The exact value will vary somewhat with tank pressure, how much depends on the reg design and if it is balanced or not- this one most likely is. You will need an IP guage to measure it.
Cracking pressure is the amount of vaccum that is required to open the second stage and allow air to flow. It is usually rated in "inches of water column", more commonly shortened to just inches. Typical value range from 0.75in (very light) to around 1.5in for an octo. Most primary second stages fall between 1 and 1.5 in. This is most easily measured by simply lowering the second stage into a container of water with the mouthpiece up. As you lower the reg into the water, at some point the reg should start to gently freeflow, that is the cracking point. If you measure the distance from the diaphragm edge to the point on the reg where the reg began to freeflow, that will give you a rough estimate of cracking pressure. If the water gets to the mouthpiece and starts flowing in, cracking pressure is higher than can be measured by this method and is fairly high, at least 1.5 to 2 inches. Not exactly a high accuracy bench test but not a bad guestimate.

 

[superstar]

davefest, herman described it perfectly, very well put herman, thanks.

 

[superstar]

davefest, you should float over to the "do it yourself" forum, much good info on keeping the older regs going.

 

[davefest]

Thanks herman, makes perfect sense. And thanks for the suggestion superstar - I'll check out DIY.

 

[regulator bj]

Drawings and info might prove helpful Regards john