Quote from: LarryC on October 20, 2012, 09:58:00 AM
Nice, but could you list the size specifications of your model. You probably did it before, but it would save time as I would like to calculate the lift force and compare the calculated results to actual of your results to wildew's.

Sure Larry.

Pod OD 87.5 mm x 107.5 mm tall 38 g.
Inner Riser OD 95.5 mm x 111 mm tall 30 g.
Outer Riser OD 103 mm x 112 mm tall 34 g.

The above were all measured before assembly and set up of the ZED and are average values of OD and height.  The rest will be derived from the build process and the above numbers since I cannot measure anything but the outer wall OD right now and even that is an approximation.

Outer Wall OD 107 mm.
Mid Retainer Wall OD 99.5 mm.
Pod Chamber Wall OD 91.5 mm.

I actually have no spare material to measure thickness!  So if anyone has a two liter Pepsi bottle and calipers, have at it.  I would estimate it at ~0.4 or 0.5 mm thick.

All end caps are 2 mm thick.  I estimate that the Outer and Inner Risers are floating ~ 2 or 3 mm above the retainer walls they would rest on when the system is at the bottom of stroke.

I'd have to tear everything down to accurately weigh the preload weight due to the weight (spacer), indicator touch plank, and indicator probe, but estimate all that to be around 380~400 g (on top of the Outer Riser mass).  The removable lift mass (jar of water) was set up to be exactly 1000 g.

Let me know if you need anything else.

M.

Quote from: mondrasek on October 20, 2012, 10:28:11 AM
Sure Larry.

Pod OD 87.5 mm x 107.5 mm tall 38 g.
Inner Riser OD 95.5 mm x 111 mm tall 30 g.
Outer Riser OD 103 mm x 112 mm tall 34 g.

The above were all measured before assembly and are average values of OD and height.  The rest will be derived from the build process and the above numbers since I cannot measure anything but the outer wall OD right now and even that is an approximation.

Outer Wall OD 107 mm.
Mid Retainer Wall OD 99.5 mm.
Pod Chamber Wall OD 91.5 mm.

I actually have no spare material to measure thickness!  So if anyone has a two liter Pepsi bottle and calipers, have at it.  I would estimate it at ~0.4 or 0.5 mm thick.

All end caps are 2 mm thick.  I estimate that the Outer and Inner Risers are floating ~ 2 or 3 mm above the retainer walls they would rest on when the system is at the bottom of stroke.

I'd have to tear everything down to accurately weigh the preload weight due to the weight (spacer), indicator touch plank, and indicator probe, but estimate all that to be around 380~400 g (on top of the Outer Riser mass).  The removable lift mass (jar of water) was set up to be exactly 1000 g.

Let me know if you need anything else.

M.

Thanks, M.


See attachment: It calculates out to your diameters with a .5mm thickness and a gap of 1.45mm.


Wayne had recommended that the height be 3 times the average diameter. This seems like your issue.
Also, if it was close to that height, your lift force would increase greatly and you would have no trouble with the .75".


Regards, Larry

Quote from: LarryC on October 20, 2012, 03:47:50 PM
Wayne had recommended that the height be 3 times the average diameter. This seems like your issue.
Also, if it was close to that height, your lift force would increase greatly and you would have no trouble with the .75".

Larry, please understand that I am not a contestant in any of the challenges.  So I have no issue.  I have only built what I could with what I could come by cheaply so that (hopefully) we could determine the proper way to test and confirm that a three layer ZED (1 Pod, 2 Risers) can be OU or not.  I understand that the proportions of my test ZED are not what has been recommended and my experience with testing it would cause me to declare exactly the same thing.  For the given diameters of the members I worked with a taller build would have definitely performed better.

But at this point I have a build that has been tested and the results given.  Even if it is an OU failure it should fit the predictions of your spreadsheet and Dennis' simulation.  So, does it?  Does your spreadsheet say this build will fail to be OU by approximately the same percentage as the measurements and calcs taken from the real world build?  If so, this is a good thing!  And I would happily run other tests for you or anyone else interested in verifying mathematical models.  Those models should not only work to predict a good build.  They should also work to show identical results for a bad one.

Thanks for the checks so far.

M.

Nice work M.
I really should ship you mine and let you play with it, but then what would I have to occupy so much time 

@fletcher, if you would - from #2647

Quote2. You know how much extra volume & weight of water must be added to the outer channel so that the Pod/Riser plus lifted mass will stroke the full 10 mm after release.

You said outer channel? - was that intentional?

Larry uses an outer channel water drop figure in the spreadsheets. I've never fully understood the significance of that. Larry?

I think I've finally worked out a nice setup method but it hasn't changed the final testing results much. If anything it has increased the lift differential of removing water from height x and pouring it back in at height y. Maybe in dual-zed land that's a benefit, not sure. It does seem to make the "work?" numbers look worse.

Setup Method - now... (ports top and bottom in each cavity - single top plate)
This had me swinging,,, inject water into the space between two retainers, with a sunk riser between them. How to control which cavity the water goes in to..... Same with adding air at the top. And all 7 cavities interact.....

Tuns out it's not so tough once you really understand the pressure gradients - OK, I'm slow.....
- With it weighted down, flood the pod chamber and close the first air vent.
- Then inject water into the first riser cavity, the trapped air will force the water up the right side of riser 1.
- Close the air vent and continue.
- It's real interesting at water port 3, the air really starts to compress in the inner chambers, reducing the differentials.
- If desired, add air in the reverse order, from outside in. ( a 100ml hydroponics syringe works GREAT! ) 

** measured water volumes in each of the chambers is about 500mL, 450, 475, 500 ish **

I'm starting to wish I had invested in some distilled water. I've got hard, high calcium water, even softened the whole thing is getting cloudy and harder to see, measure. Maybe time for a vinegar rinse.

Current testing setup:
Dry assembly - flat top pod / riser + hardware and blocks is 16Lb 10Oz | lift weight is 16Lb
Fluid cycled is 13 Fl Oz
Head pressures, POD outward, in inches of head
Sunk to a stop without the lift weight: 8 - 16 - 14.5 - 9.25
Pre-charge 26 - 26 - 20 - 11
Full lift of .75  34 - 26.5 - 17.5 - 9.25

With this setup there's quite a bit of margin - interesting to watch it approach the limits and then back away from them as it lifts. I could go to a full inch pretty easily but I'm starting to think the lift is the gravy, almost a side-effect of what's really happening in the system - it NEEDS to charge under added resistance; but what's it giving back?? 

Maybe time to add layer 4 but it definitely has gotten MUCH more complex with each added layer.

Nice little cheer from Mark D on the smart scarecrow show
From me: Go get 'em Wayne !
Dale

Is it a secret?

It's Sunday morning in Oklahoma. Everyone is at church, dressed in their Sunday finest. This afternoon, after a nice big Sunday meal, the valiant crew of 108 will no doubt roll up their sleeves and return to work on the advamcement of the new redefined Zed technoology.

QuoteHello and Welcome,

Yes, Hello and Welcome, We the cooperation of our now 108 team members - we have just advanced our system to an entire new level production with dramatically reduced capital cost and reduced complexity.
This Advamcement in our ZED technoology has massively opened our market - we are in the process of redefining our business objectives.
This is the Adventure in the discovery!
questions to me, Wayne Travis at This e-mail address is being protected from spambots. You need JavaScript enabled to view it
I will be glad to answer.
Sincerely Grateful
Wayne Travis

(sic)
http://hydroenergyrevolution.com/index.php/letter-from-the-president


Well, here's a question then: Are you "up and running" yet, as your October 15 update promised you'd be by last Wednesday, Friday at the latest?
Is it a secret?


Sincerely Doubtful
--TK