|
|
Post by vance on Jan 6, 2019 11:16:52 GMT -8
Phil, have you also done a measurement and comparison with you Hydrdotwin-II? JB No, I haven't done that. The Sportsways plunger might be made to work, but I'm not going to mess with it. At least not yet. The Conshelf parts are a better fit. I think the Sportsways shaft has a larger diameter than the USD crown block, and is far too long. It would allow the use of an HW orifice, but the Titan is readily available. There is the potential for the HW orifice to create more space for the guts to fit into the short valve bodies though....
|
|
|
|
Post by vance on Jan 6, 2019 11:40:17 GMT -8
I think there's good evidence that Creed's (Michael L.) experiment is a success. Here's some interesting measurements from the Conshelf VI and Healthways (long) valve bodies: Conshelf HW top bore .500 .500 bottom bore .460 .440 transition .390 .385 total depth .850 .925 I inserted the crown block into the valve bodies and measured to the top of the block (easier to do than the little ridge). Conshelf=2.225 HW=2.245 The internal dimensions are very close. The Conshelf/Titan setup in the HW body should work! The shelf Herman mentioned is within .005 of the right place to hold the crown block in position. The volcano orifices are at different depths, making the overall depth of the HW .075 lower, but a shim under the orifice could easily rectify that. There is a relatively significant difference in the bottom bores of .020, which MIGHT reduce the airflow past the crown block. I say might, because the transition is beveled on the HW, and straight on the Conshelf. More air should get by the bevel than a straight cut, so it might not be reduced very much, if at all. (This is a guess. I have not tested this, and have no way of doing so!) This picture shows the transitions on both valve bodies:  |
|
|
|
Post by vance on Jan 6, 2019 12:03:20 GMT -8
As I mentioned, I don't see much use for this w/o a venturi setup like the GL has. The difficulty is that the GL valve is shorter than the long version of the original Scuba's valve. I have not yet tried to stuff the Conshelf bits into a GL valve, but I know some people who have tried to recreate Creed's experiment have not been able to close their valves up. I am waiting for responses to my claim that the Healthways single stage valve can be converted to a balanced valve with Conshelf parts before taking a GL apart and trying it out for myself. I'd still like to see responses! Seeing as how the long HW valve is .075 deeper than the Conshelf, there is at least that much extra room to work with. A modified HW or Sportsways plunger/dished seat combination would add a bit more room than the raised volcano orifice allows. I just need to measure a GL valve's overall depth to see what we're talking about. Also, I have one of Herman's HP valve assembly tools, which makes it much easier to drive that retainer in. But, I don't care to do all that if anyone can explain to me why the balanced Healthways valve isn't going to work. SEE EDIT! Edit: I said I wasn't going to do it, but, like always, I did it. We got trouble from the get-go:  You'll notice that the GL has a lot less space between the retainer groove and the transition. Like .200 less. This will require a shorter crown block. I didn't bother to measure the whole valve since I'm thinking we're dead in the water. I will absolutely not get involved in this. Until I do..... |
|
|
|
Post by SeaRat on Jan 6, 2019 16:47:04 GMT -8
I think that I tried this some years ago, and was not successful. I could not get the sintered filter down where I could engage the C-clip.
John
|
|
|
|
Post by vance on Jan 6, 2019 20:19:10 GMT -8
I think that I tried this some years ago, and was not successful. I could not get the sintered filter down where I could engage the C-clip. John Yes, that would be very difficult, if not impossible, with the short valve. The space between the ledge and the clip is very small on the short ones. I'm not sure there's any clearance between the crown block and the clip groove. I have not measured and compared all aspects of the 3 types of HP valve body, but I think it's reasonably certain that the measurements of the short valve that came in all 3 generations are the same. Of course, the GL had a covered top and venturi nozzle which added some differences to that end, but from the other end, I think they're the same. This could be a mis-statement. There might have been more differences built into the valves over the models and years. I've never heard of or noticed any differences like that in the 30 or so Scuba A, B, and C models I've worked on. Nor have I ever heard of ANY references to long and short valve bodies ANYWHERE except by me or in threads where I've brought it up! |
|
|
|
Post by vance on Jan 7, 2019 18:38:00 GMT -8
Herman,
What is your opinion about this? You weren't sure about the efficacy of the conversion, but I have provided additional info about it that you might have forgotten or were unaware of. I think it works. Am I out on a limb? I don't claim to be an expert, and I'm only interested in learning, not in being right. There's so much I don't know....
|
|
|
|
Post by herman on Jan 8, 2019 3:48:33 GMT -8
I'm no expert on it either, esp the HW. There is no reason technically you can't make a balanced single stage reg using these parts, the issue is proper spacing/clearances. Get those right and is should work. The crown block (CB)has to be located at a specific distance from the orifice, there has to be enough travel for the HP seat when it's fully raised by the pin. The spacing above the CB is not as critical. IF you ensure the HP seat can never be raised above it's limits (ie, at maximum travel it never bottoms out in the CB)then the space above the CB can be reduced to a few thousands with no spring. The upper spring is to keep the CB seated but at the same time to allow it to be lifted if the pin goes in too far. The old MK-12/Trieste/ Titans are an example of the seat not floating (much). Keep in mind they do not have the filter above them so the tolerences are easier to keep tighter. I would be concerned eliminating the upper spring in a single stage due to the lever configuration. Without doing any measuring, my gut feeling is they have the potential for too much travel to risk a nonfloating CB. A floating CB and mechanical limits on lever travel are a good idea.
To accomplish this, my best guess, again without doing any measuring, is the internal shelf in the HW nozzle will need to be adjusted up with a spacer or down by turning out the nozzle a bit deeper, no idea of which without measuring and calculations. You will also have to make a different pin. Being fairly long, it needs to be of a hard material and to a tight tolerance in the portion that goes into the HP seat because the gap around the pin inside the seat is critical to the operation of the balance chamber. Rather then turning the entire pin, a better way to make them is a 2 piece design using hardened SS pins for the smaller dimension and then pressing on/ locktighting a brass pusher section onto the pin. There are a lot of details that need to be worked out to make this work.
|
|
|
|
Post by vance on Jan 8, 2019 9:19:10 GMT -8
Thanks for the explanation and the ideas, Herman!
I want to address some of your points by inserting comments and questions into your post. I want to clarify that for now I'm mainly interested in addressing the modification of the long HW valve, NOT the different short valve that is found on the GL. Some of your comments are directed at the problems one would find in modding the short valve, and while I appreciate them, I'm storing them away for future consideration! My comments are in italics. I'm no expert on it either, esp the HW. There is no reason technically you can't make a balanced single stage reg using these parts, the issue is proper spacing/clearances. Get those right and is should work. The crown block (CB)has to be located at a specific distance from the orifice, there has to be enough travel for the HP seat when it's fully raised by the pin. The internal space between the CB and the orifice on the Conself and HW are different. The HW's is .075 longer. This allows sufficient room for the HP seat to travel + .075, and can be easily shimmed.
The spacing above the CB is not as critical. IF you ensure the HP seat can never be raised above it's limits (ie, at maximum travel it never bottoms out in the CB)then the space above the CB can be reduced to a few thousands with no spring. The upper spring is to keep the CB seated but at the same time to allow it to be lifted if the pin goes in too far. The old MK-12/Trieste/ Titans are an example of the seat not floating (much). Keep in mind they do not have the filter above them so the tolerences are easier to keep tighter. I would be concerned eliminating the upper spring in a single stage due to the lever configuration. Without doing any measuring, my gut feeling is they have the potential for too much travel to risk a nonfloating CB. A floating CB and mechanical limits on lever travel are a good idea. To accomplish this, my best guess, again without doing any measuring, is the internal shelf in the HW nozzle will need to be adjusted up with a spacer or down by turning out the nozzle a bit deeper, no idea of which without measuring and calculations. The spacing above the CB and position of the shelf are w/in .005-.0025 in both valves, so this is not an issue on the LONG valve body. The short body valve's spacing above the CB is much shorter and would require eliminating the spring and possibly cutting down the CB. The Conshelf part may not have enough material to remove to fit.
You will also have to make a different pin. Being fairly long, it needs to be of a hard material and to a tight tolerance in the portion that goes into the HP seat because the gap around the pin inside the seat......
Do you mean clearance where the pin fits through the orifice or where it contacts the seat?
....... is critical to the operation of the balance chamber. Rather then turning the entire pin, a better way to make them is a 2 piece design using hardened SS pins for the smaller dimension and then pressing on/ locktighting a brass pusher section onto the pin. There are a lot of details that need to be worked out to make this work.
This is a good idea! Thanks for taking the trouble to make these explanations. From what you have said, the Conshelf guts in the long HW valve body seem to fit and function correctly. |
|
|
|
Post by nikeajax on Jan 8, 2019 9:46:46 GMT -8
So, wouldn't you test this with a manometer and both high and low tank pressures?
JB
|
|
|
|
Post by vance on Jan 8, 2019 14:33:48 GMT -8
So, wouldn't you test this with a manometer and both high and low tank pressures? JB Whoa! Let's not get ahead of ourselves, Buuuuddy! Test it?  I'd say that's the next step. Who's got a manometer? Not Vance. |
|
|
|
Post by nikeajax on Jan 8, 2019 15:13:18 GMT -8
Yool find a recipe fer one in Basic Scuba...
W'll how elz ya gunna know if'n it's bellunst?
JB
|
|
|
|
Post by herman on Jan 8, 2019 15:16:12 GMT -8
Based on what you have posted, at first glance it should work on the longer models. I have not looked in detail so there may be something I am missing. The CB balances the HP seat by allowing air to pass from the IP or in this case ambient side of the seat around the pin to the top of the HP seat stem and into the area behind the orings. If the fit is too tight, the air will not pass around it correctly and it will affect the balancing. How it all works is a bit more than I care to type. I highly recommend you consider getting a copy of "Regulator Savvy" by Peter Wolfinger. He was the head engineer at Scubapro for a number of years. His book goes deep into the physics of how regs work. IMO, it's a must read for anyone working inside a reg, esp if you are modifying one, this is the Bible for reg techs. www.scubatools.com/c-23-regulator-savvy-book.aspxOnce you get the internal parts worked out, have you thought about how you are going to verify the HP seat is holding pressure? There is no IP to check so some way is going to have to be devised to check to see if the seat is holding. The simplest way I can think of is to attach the assembly without the cans to a pony bottle (I have a hose with a yoke fitting on it I use) and submerge assembly in water to check for bubbles. Once that is done then you have to move on to testing to see if the balancing is working. I suppose the easiest way is with a manometer or magnehelic gauge to check cracking pressure at various tank pressures. You can find used mags on ebay occasionally for $25ish. Manometers are very easy and cheap to make so it may be your first option....and unlike a mag, are impossible to destroy if (when!) you hit them with a run away pressure spike. A word of warning....DO NOT INHALE FROM THE SUPPLY HORN OF ANY DH REG!!!! The venturi can and will cause a pressure spike if it slams the valve open and if you are the unfortunate one to be inhaling on the horn at the time, severe lung damage can occur. Don't inhale off any DH reg without the hose loop to bypass the extra air if/when a freeflow occurs. This is esp true on the Gold Label and the Kraken, both of which have very effective venturi systems. |
|
|
|
Post by vance on Jan 8, 2019 16:01:42 GMT -8
Thanks for the replies. I will study on this, look into getting a copy of the "Bible", and probably make a manometer!
Thanks for the warning about inhaling directly off the air horn! I had heard about that and have always followed that rule.
|
|
|
|
Post by cnotthoff on Jan 8, 2019 16:23:07 GMT -8
|
|
|
|
Post by herman on Jan 8, 2019 16:50:46 GMT -8
Mags come in a wide variety of pressure ranges and styles. That one would be OK for beginning testing of this project but it's really too high a scale for most scuba use. A bad cracking pressure is in the 2 IWC range with really good ones in the .5 to .75 IWC range with most modern second stages coming in between 1 and 1.5 IWC. Also, with such a wide range, seeing small changes in cracking pressure would be difficult. I prefer a 0-3 or 3-0-3 for initial testing and for fine tuning one in the 0-1 range. The 3-0-3 one makes a really nice first one to get since it allows you to see exhaust pressure without swapping hoses.
IWC= inch of water column
|
|
