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Post by nikeajax on Sept 26, 2012 8:57:19 GMT -8
What's the deal with tilt-valve regs; seems like nearly all the first generation SH'ers were? In the early-mid 1960's, the tilt-valve was abandoned, for the Calypso-style, then in the early-mid 1970's they crept back, I believe even the USD-Calypso became one in it's last forms, ironically!
I hear people writing about the early ones with complete contempt, but then you have regs like the Tekna and Pilot that seem to be revered...
Jaybird
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Post by cnotthoff on Sept 26, 2012 9:15:20 GMT -8
Oh my, the upstream vs. downstream second stage issue. A tilt valve is an upstream valve, meaning that the seat is upstream of orifice, and opens against the flow of air.
The good thing about a tilt valve is that it will function pretty much the same with any supply pressure. That is why they are still popular in hookah system where the apparent supply pressure varies with depth.
A problem with an upstream valve is that it shuts off when supply pressure gets too high, i.e. a blown first stage seat. That's why a pop-off valve is necessary in a system with an upstream valve. Tekna incorporated one in their upstream T-2100 servo-assist second stage. If you have one, hold the second stage and give the hose a tug.
I guess the bottom line is that tilt-valve second stages have consistent crappy performance.
Good Dives,
Charlie
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Post by nikeajax on Sept 26, 2012 9:40:45 GMT -8
Thanks Charlie--really! It's not just that I want to know, 'cause I honestly do, but more of trying to get people to post something on here, as opposed to just PMing and complacently LURKING in the shadows  I love this forum, it's an amazing resource, and I want to keep it that way: yeah, I may be obnoxious with all my questions, but that's why I go by...  |
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Post by SeaRat on Sept 26, 2012 13:15:06 GMT -8
Actually, when I was first diving I switched from a 38 cubic foot tank and a Healthways SCUBA double hose regulator to a 72 cubic foot tank and a Healthways Scuba Star regulator, a tilt valve. It was very simple in design, and breathed well compared to the Healthways SCUBA (mainly because of regulator positioning, I think). The photo is of me by my girl friend, Elaine McGinnis, while I was in high school in the neighborhood of 1962-3. The outing was with the Salem Aqua Club, and we were the Salem Junior Aqua Club. I later switched to an AMF Voit VII Viking 40 regulator, the same design as the USD original Calypso. This regulator was super-easy to breath compared with the Scuba Star. The downstream design was advertised by USD as superior to the tilt-valve, in that it could deliver more air. To prove it, Hannes Keller took it on several deep dives, culminating in a disasterous 1000 foot dive.   www.divernet.com/other_diving_topics/160537/the_atlantis_affair.htmlThe regulator worked better than the humans on that dive. John Attachments:
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Post by nikeajax on Sept 26, 2012 15:15:44 GMT -8
John, do you think the Scubastar would make a decent alternate air source for my Scubair-300? I have yet to tear the Scubastar apart, is there anything peculiar about its gizzards?
I've started making a mold for diaphragms for them: as a sculptor, it's fun, but a challenge free-handing it. Funny, it took me a while before, "Well duh, put the $#@!!!! regulator's top on it..." looks EXTREMELY close!
Jaybird
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Post by Nemo on Sept 26, 2012 16:41:03 GMT -8
Well, y'all got me beat. I'da thunk a tilt valve was part of a pinball machine...  |
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Post by cnotthoff on Sept 28, 2012 15:03:49 GMT -8
Tilt valve 2nd stages make a good octopus. They are very reliable and don't tend to freeflow. I used a Waterlung tilt valve 2nd when we first started dragging around enough 2nd stages to let everyone share air until it's gone.
Charlie
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Post by nikeajax on Sept 28, 2012 16:30:19 GMT -8
Charlie, again, thanks; that's what I was hoping to hear! ;D
Jaybird
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Post by Deleted on Sept 28, 2012 18:00:10 GMT -8
I've a 30 year old Tekna 2100b (a tilt valve) that has never given me any trouble, except once, never could over breath it, never had it serviced either and it still breaths great.
That exception was my fault, pulled it apart to remove a mouthpiece bit tab that I somehow managed to bite through and blew into the reg body. Then not putting it back together properly resulted in breathing issues, until I corrected my ham fisted servicing.
I bought the Tekna because it was light and blew bubbles out only on one side of my face..........all because in my area there were no repair parts available for my RAM back in the 80's.
The internet did not exist then and sourcing was iffy.
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Post by nikeajax on Sept 29, 2012 8:48:39 GMT -8
OMB, I have one of those, but have yet to use it: so what makes it a "B"? I read a thread a while back where you were saying how much you liked them. It has a very healthy exhaust diaphragm and the escaping air doesn't really have much in the way to work against either; I think the Calypso-IV has the same size, but that was just me eyeballing it...
I remember Charlie saying, you shouldn't take the servo apart on those, as it's very easy to make them unusable...
I see how the tilt valve can be very dynamic: the harder you breath, the more the lever is going to move and give you more air: so it's very dependent on the exhausting...
Jaybird
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Post by nikeajax on Sept 29, 2012 12:58:53 GMT -8
Am I mistaken? The Scubastar isn't adjustable: neat-o! Charlie, you're right, it should make an ideal octo; it's not that I didn't believe you, I just didn't realize how, um, "bullet proof" these second stages are, "Like groovy-man!"
Jaybird
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Post by nemrod on Sept 29, 2012 17:18:11 GMT -8
Upstream valves also have interesting issues when the first stage malfunctions and the IP goes sort of high. BOOM. But as long as it was with a downstream second, no explosions, darn.  Healthways and breaths well in the same sentence, hmmm, are you sure? Most of the ones I recall using were sort of like sucking through a straw, a really small straw.  Nem |
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Post by Nemo on Sept 29, 2012 23:29:10 GMT -8
Actually, when I was first diving I switched from a 38 cubic foot tank and a Healthways SCUBA double hose regulator to a 72 cubic foot tank and a Healthways Scuba Star regulator, a tilt valve. It was very simple in design, and breathed well compared to the Healthways SCUBA (mainly because of regulator positioning, I think). The photo is of me by my girl friend, Elaine McGinnis, while I was in high school in the neighborhood of 1962-3. The outing was with the Salem Aqua Club, and we were the Salem Junior Aqua Club. I later switched to an AMF Voit VII Viking 40 regulator, the same design as the USD original Calypso. This regulator was super-easy to breath compared with the Scuba Star. The downstream design was advertised by USD as superior to the tilt-valve, in that it could deliver more air. To prove it, Hannes Keller took it on several deep dives, culminating in a disasterous 1000 foot dive. www.divernet.com/other_diving_topics/160537/the_atlantis_affair.htmlThe regulator worked better than the humans on that dive. John Interesting facts; entertaining too. You oughta write a book. And no I'm not being a wise guy.  |
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Post by nikeajax on Sept 30, 2012 18:06:03 GMT -8
I'm trying to figure out a way to "restore" the LP seat on my Scubastar; ain't no way anybody has any of those just laying around... I'd love to be wrong!
One thought is to trim off, maybe, 1/32, and with a paper-punch, make a new seat with some neoprene with a hole for the shaft to fit through and glue it in; this way I could replace it at will, hmmmmm?
Jaybird
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Post by cnotthoff on Oct 1, 2012 13:34:33 GMT -8
Damn, your box with the Calypso just went out Friday. TUSA (Tabata USA) still makes a tilt valve 2nd stage. Their seat should work in your Scubastar. The length of the stem may be different. If you can't manufacture one, send the dimensions and I'll check stock.
The main valve on the Tekna 2100B and the Oceanic Omega consist of a rubber plate that fits against a metal housing with many holes. The rubber conforms to those holes after a while. If the rubber plate is not oriented exactly as it was before removal (nearly impossible) it will always leak a little air. I'd probably part with some of the my Tekna backstock. I doubt I'll ever get one of those in for service again.
Good Dives,
Charlie
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