Questions...

myndzi · Post by **myndzi** » Mon May 01, 2006 1:24 am

For better context, here's a horrible dis-proportionate scribble of what I have in mind. I didn't know how to draw the one-way valves really, so they are just little arrow sections... the rest I more or less have an idea of the parts, excepting the sliding seal thing. I'd probably end up adding a few cosmetic things like handles in appropriate places, as well.

Yes, smooth sliding was my initial worry, too. A lubricant should easily do the trick.

I think the question is if you can have good sealing AND movement, or if they are mutually exclusive. I should be able to test if I can come up with the unknown parts in the sketchy picture above and create the tank only. I can seal off one end and pump water in the other and observe what happens. I kinda want to do it today now, but it's getting a little late... I'll stop by my Dad's on the way home and see what he has to say.

Silence · Post by **Silence** » Mon May 01, 2006 2:13 am

As I said, if you want a nice handle, that can replace the PC cover. By connecting the pump tube to the "barrel" with blocked PVC, you will support the barrel, ball valve, and nozzle(s), while having a perfect handle from which you can use the ball valve like a trigger. This is my "trademark" design--I want to use it for every homemade I make--especially when you use a connector at 45 degrees. A slanted connector will allow you to keep the pump farther back and make the handle more comfortable.

myndzi · Post by **myndzi** » Mon May 01, 2006 5:11 am

SilentGuy wrote:As I said, if you want a nice handle, that can replace the PC cover. By connecting the pump tube to the "barrel" with blocked PVC, you will support the barrel, ball valve, and nozzle(s), while having a perfect handle from which you can use the ball valve like a trigger. This is my "trademark" design--I want to use it for every homemade I make--especially when you use a connector at 45 degrees. A slanted connector will allow you to keep the pump farther back and make the handle more comfortable.

..I *was* considering 'borrowing' that one

So I had a talk with my dad tonight, it seems this whole slidey thing may simply be a moot point. I am ordering some LRT to test with, and will report back the results. My dad insists that there will be no worthwhile problems with simply running tubing the length of the PC, but he also insists that it will become weak/useless or break after a few inflations. We will see who is right on what counts! >

Thank you guys for all your replies, I'm goin to bed for the night.

Silence · Post by **Silence** » Mon May 01, 2006 12:21 pm

You don't need to worry about the LRT weakening--that never happens (or I don't think it does).

However, there is still one major problem...

How will you seal an O-ring to the inside of a PVC tube? You can do so with the outside, but the consensus in soakerdom is that you can't do so inside. It's impossible to work in such a small space.

I only thought of this late last night...

m15399 · Post by **m15399** » Mon May 01, 2006 6:12 pm

The LRT will weaken, as does everything else in this universe. ...almost everything...

I was not aware of any consensus, but I think it shouldn't be too hard to seal an oring inside a pipe. If you had the right size o-ring, you could squeeze it in a crack on the inside of a coupler/piece of PVC. I'm not really sure what that has to do with anything, though... Where is this internal oring?

Silence · Post by **Silence** » Mon May 01, 2006 8:04 pm

Well, the LRT will weaken, but not significantly after only a few fills. Over time, the rubber will dry and be more prone to cracking. There have been some reported cases in which, after several years, some CPS guns' PC bladders crack.

The consensus about the (near?) impossibility of internal O-rings was reached in a somewhat recent thread--though the thread may be hard to find. I believe it had been going a bit off topic, so the thread title won't help.

You could place the O-ring between two PVC pieces, a technique I had thought of at one point, but that would probably bring in too many complications. It is possible, though.

m15399 wrote:Where is this internal oring?

Look at the diagram in Post #9--do you see the piece that one end of the LRT attaches to and that slides along a long PVC pipe? The O-ring needs to be attached to the inside of this short piece to keep a seal as it slides.

myndzi · Post by **myndzi** » Mon May 01, 2006 9:03 pm

I wouldn't give it too much thought, I may be able to do without that entirely. But, if I had to do it, I'd probably glue a piece of PVC into a coupling, but not push it in all the way; it'd leave me a little gap to squeeze the O-ring into, but would be a bit of a pain to set up. I guess I could put some sort of spacer in when I glue it.. and would have to make sure to clean out any excess glue immediately.

Silence · Post by **Silence** » Mon May 01, 2006 9:16 pm

Well, if you can pull it off, then that's great; otherwise, it will just be a waste of time, effort, and PVC.

Who knows, maybe you can be the first to create a seal on the inside of PVC pipe

. It may not be that hard, but it would still be something to brag about.

I remembered one of the threads that talked about internal O-rings--it was my failed "Displacement Pump" project.

isoaker_com · Post by **isoaker_com** » Mon May 01, 2006 10:07 pm

Instead of having the PC slide over a filling tube, why not just have the filling tube flexible so the attachment can be fixed, but the tube can move as the bladder expands? A sliding, water-tight seal as one of the earlier diagrams appears like would be very tricky.

Also, while the horizontal stretch of LRT helps with available power of the chamber, I'm not 100% convinced it is needed. If you fix both ends of a piece of LRT, allowing it only to expand outwards, it should still generate decent pressure, though may require an added layer to increase pressure a little more. The main problem is that pressure from the LRT with fixed ends first pushes inwards, then out a nozzle once the nozzle is open. This would likely reduce how laminar the flow out the PC is, but not sure how significant this is. I figure many stock soakers have PCs at right angles to their nozzle, yet can still push water decently. LRT with filling at opposite side of the nozzle would be a linear set-up. Perhaps not as potent as a design like CPS2500/2000 set-up, but should be better than any right-angled PC designs (i.e. WW Piranha/Blazer).

myndzi · Post by **myndzi** » Mon May 01, 2006 10:36 pm

I've never been afraid to 'waste' time and effort learning things. And the PVC is free -- there are more scraps and ends laying around in my dad's garage than he needs, surely.

As for the LRT contracting 'forwards', I think that sounds a little flimsy. I doubt there will be much of a loss in power from that... I was only thinking 'outside the box' so to speak since intitally I was under the impression that fixing both ends would be a bad idea. That, however, is what I intend to test when my tubing shows up

Edit: Oh, and since you mentioned the design of the CPS 2000 -- is there a thread or a link you have handy that shows the internals of that gun? I was pretty curious after hearing so much about it.

Silence · Post by **Silence** » Tue May 02, 2006 12:52 am

@ iSoaker_com: Are you thinking of using a hose to connect the second check valve and the PC? That might work, but I think hoses can be a little clumsy.

Even if you fixed both ends of LRT, the water would push in all directions--including lengthwise. This force would likely damage the soaker.

I'm not sure you need to worry about laminar flow in this situation. The laws of physics claim that while the CPS bladder may only be pressing towards the center of the bladder, the pressure can be transferred and used to force water out in the correct direction. Water will not be moving from the actual latex to the center of the PC and then turn toward the opening.

@ myndzi: There's some site (maybe ZOCCOZ's? just a guess...) that claims to have the most comprehensive gallery of soaker internals. Check it out if you want to.

DX · Post by DX » Tue May 02, 2006 1:26 am

@ myndzi: There's some site (maybe ZOCCOZ's? just a guess...) that claims to have the most comprehensive gallery of soaker internals. Check it out if you want to.

Not for long! Just wait 'till I really get SM v2 rolling...

Until then, SSCentral has a great internals gallery, that's where I looked for those kinds of pics for quite a while.

I really want to use LRT in a CPR-style homemade, but I'm really a fossil when it comes to CPHs. One question, is it better to have the LRT exposed in the open, like in some of Ben's CPHs, or enclosed in a pipe?

Silence · Post by **Silence** » Tue May 02, 2006 1:35 am

I don't think exposure will destroy LRT. It appears to be some pretty tough stuff.

Of course, Ben should know...and considering his CPHs use exposed LRT, I doubt he's ever experienced a problem.

Duxburian, what do you think of the proposed inline CPH designs? At this stage, they are probably more important than the finer details such as LRT exposure.

m15399 · Post by **m15399** » Tue May 02, 2006 2:02 am

I think it's best to have the LRT enclosed. If it was open, it would dangle around and be annoying. As long as the tubing is big enough not to restrict expansion, it should be ok.

Silence · Post by **Silence** » Tue May 02, 2006 2:38 am

Yes, dangling would be a problem if the LRT is not fixed somehow at both ends. However, going back on topic, I still don't see why we can't hook up the bladder at both ends. This (1) allows for linear flow and (2) is cleaner and more supported as shown in the recent posts including this one; and there are probably a few points that I missed. Sure, the design may be more complex and expensive, but we can forgive that, especially if we (myndzi) have access to plenty of PVC.

I'm not saying that this idea seems to have been written off; rather, I hope more people would support it as it is unique and innovative and could expand our knowledge of CPR (which, as a whole, has been minimal). I encourage myndzi to test this out before worrying about covering the PC.