Inside the Tekna Regulator

[Akimbo]

Long ago I was at a Northern CA scuba shop looking at Tekna regulators. I asked the sales guy if I could service it myself. "No way," he said, "it's extremely complicated and you'd probably mis-adjust it and die."

He would probably gave the same answer if you asked about mask straps.

 

[Fibonacci]

And finally the poppet. I don't know what else to call it. It's a miniscule rubber donut on the needle that doesn't lift straight off the seat but rather tilts off when you create a vacuum by inhaling:

View attachment 383020

This one is in good shape, as were about 50% of the dozen or so I worked on. Here's one that's not so good (I pulled this one off the needle):

You know that poppet seal look a lot like a square section o-ring... maybe worth a try?
Square O-rings Buna - Nitrile - Tetraseals® or lathe-cut rings

 

[2stroketony]

Have either of you made any progress on the Tekna B2100 pilot valve seal? I am working to find the original maker and the subtance that was used.
2stroketony
Idaho

 

[2stroketony]

Long ago I was at a Northern CA scuba shop looking at Tekna regulators. I asked the sales guy if I could service it myself. "No way," he said, "it's extremely complicated and you'd probably mis-adjust it and die."

Well, some years later I decided to find out. I've been buying used Teknas on eBay for the past several months and restoring them---when possible. The design is quite unique.

The valve bodies came in brass and plastic. People tend to look down on the plastic ones and I don't know why---they're lighter, will never corrode, and have exactly the same insides. Here's one of each:

View attachment 383012

Let's take the brass one apart:

View attachment 383013
And take off the circlip:

View attachment 383014

Remove the rubber spacer:

View attachment 383015
Two holes on the top and a bolt on the bottom:

View attachment 383016
With a socket on the bolt and needlenose pliers in the holes, we can take it apart:

View attachment 383017
And here's the innards:

View attachment 383018
Bolt on the left, strong spring to keep things together, tiny spring to keep the needle poppet square on its seat. Looking inside the housing we can see the seat:

View attachment 383019
And finally the poppet. I don't know what else to call it. It's a miniscule rubber donut on the needle that doesn't lift straight off the seat but rather tilts off when you create a vacuum by inhaling:

View attachment 383020

This one is in good shape, as were about 50% of the dozen or so I worked on. Here's one that's not so good (I pulled this one off the needle):

View attachment 383021

An interesting system---very little that can go wrong, and zero possibility of adjustment. It either works or it doesn't. I've tried replacing the degraded rubber donuts with all sorts of stuff---o rings, teflon, gaskets, etc.---but I haven't found the magic material yet. Some are too hard: the poppet won't seal on the seat and the regulator free flows. Some are too soft: the regulator holds pressure, but it takes too much effort to tilt the poppet off the soft seat to start airflow. I'll find it eventually.

So there you have it, the inside story on a long-forgotten technical marvel. Hope you enjoyed it.

Hey Will

Have you found the right stuff to fix the seat yet? I have tekna 2100s and am exploring the fellows who designed and then the company who manufatured them through another who was friends with some of them in Redwood City, California.

I have many parts but none of the levers with servicable "gook" seats.

I can be contacted at 208-709-5609.

Thanks,

Tony

 

[William Farrell]

Sorry, I tried o-rings (too soft) and several epoxies (too hard). I'm guessing the original was some sort of fairly hard rubber.

I have several working Tekna regulators and would be happy to sell them----not for a profit, just to recoup costs. Email bf@vstat.com if interested.

 

[William Farrell]

I DID IT!!!

The answer to the valve seat riddle was so obvious it's painful. If you want to make a small custom donut-shaped regulator valve seat, why not start with.........a large regulator valve seat? Duh.

I had a couple of spare seats from working on "standard" vintage regulators, and bought a hole punch on eBay. I tried 2.5mm and 3mm holes, and 3mm seemed best. I removed the cup that holds the seat from the needle---it's just crimped on. I discovered this was best done inside a plastic bag, after sending one cup into outer space, never to be seen again. Turns out a standard seat is way too thick, so I cut it in half after punching it out. I then drilled a small hole in the middle that the needle would fit through, and crimped the cup/seat back onto the needle. IT WORKED!

The picture below shows the full assembly on the bottom, and needle/cup, standard valve seats, and test-punched donuts on top. I need to order a few more standard seats, as I have 3-4 more regulators that I can now finish restoring.

 

[spoolin01]

Nicely done! Turns out one of the three seats I have needs refurbishing. Is the cup just pinch-crimped on the shaft? That nipple end is just slightly crimped?

 

[rhwestfall]

Probably shouldn't have tossed mine in the garbage, but when the ring that held the valve assembly into the body cracked while in years of storage, I really lost interest.... A metal bodied one always fascinated me... Moved on to other regulators though.

YMMV

 

[William Farrell]

Nicely done! Turns out one of the three seats I have needs refurbishing. Is the cup just pinch-crimped on the shaft? That nipple end is just slightly crimped?

Yes, just crimped. Getting it off is harder to describe than do, but I'll try:

1. Put the needle in a vise horizontally, cushioned with hard rubber.
2. Hold a pair of pliers loosely on the needle, with the edge of the pliers touching the cup.
3. Use the hammer to hit the pliers so as to knock the cup off the end of the needle. It'll take a sharp blow or two.

As mentioned above, do this inside a baggie or you'll never see the cup again.

 

[William Farrell]

Probably shouldn't have tossed mine in the garbage, but when the ring that held the valve assembly into the body cracked while in years of storage, I really lost interest.... A metal bodied one always fascinated me... Moved on to other regulators though.

YMMV

Every one of the plastic rings I had (4, maybe) broke. Definitely the weak point on the regulator. They did make plastic regulators with metal retaining rings, though, and I have a couple of those.