[Ocp-europe] RuggedPOD v2 sealing feedbacks and improvements

Jean-Marie Verdun jean-marie.verdun at splitted-desktop.com
Tue Jul 7 19:45:10 UTC 2015


Hi Bill,

This is what the team worked on today ;).

Attach are some interesting data. We ran static mechanical simulation as 
to evaluate the stress that the top cover is experiencing. As you can 
see it is quite high, but displacement with a thickness of 12 mm 
aliminum or 5mm stainless steel shall be ok. The 5 mm stainless steel is 
the current design (but it is really heavy), while the 12 mm aluminum is 
the one we are thinking about.

So we plane to move to aluminum top cover.

Regarding o-ring this is the new design (Calque 1.png). We moved to a 4 
mm O-Ring instead of 3.5. The locking mechanism doesn't use anymore 
threaded rod, but "screw" which are bolted. We are also welding a new 
part at the top of the tank as to improve flatness and rectify die 
casting poor quality process.

Feedbacks welcome !

Jm



Le 06/07/15 23:38, Carter, Bill a écrit :
>
> Can you use a large rubber o-ring around the entire top cover.
>
> The o-ring will allow for movement and expansion/contraction without 
> affecting the seal.
>
> Bill
>
> *From:*ocp-europe-bounces at lists.opencompute.org 
> [mailto:ocp-europe-bounces at lists.opencompute.org] *On Behalf Of 
> *Thierry Dupeux
> *Sent:* Monday, July 06, 2015 12:16 AM
> *To:* jean-marie.verdun at splitted-desktop.com; 
> team at ruggedpod.qyshare.com; ocp-europe at lists.opencompute.org
> *Subject:* Re: [Ocp-europe] RuggedPOD v2 sealing feedbacks and 
> improvements
>
> Hi Jean-Marie,
>
> I think a screw with large head going from the top of the top cover 
> into threaded hole, avoid need for glue. I think it would be better 
> solution and nicer look.
>
> However, I cannot comment on dimension and number of screws.
>
> Best Regards, Thierry.
>
> ------------------------------------
>
> *Thierry Dupeux**
> *mobile: +33 (0) 6 75 86 48 89
>
> *From:*ocp-europe-bounces at lists.opencompute.org 
> <mailto:ocp-europe-bounces at lists.opencompute.org> 
> [mailto:ocp-europe-bounces at lists.opencompute.org] *On Behalf Of 
> *Jean-Marie Verdun
> *Sent:* Sunday, July 05, 2015 10:33 PM
> *To:* team at ruggedpod.qyshare.com <mailto:team at ruggedpod.qyshare.com>; 
> ocp-europe at lists.opencompute.org <mailto:ocp-europe at lists.opencompute.org>
> *Subject:* [Ocp-europe] RuggedPOD v2 sealing feedbacks and improvements
>
>
> Hi Folks,
>
> I spent some time drawing the concept of the top sealing that we used 
> for RuggedPOD v2.
>
> The sealing concept is quite easy to understand. We roughly used a 3D 
> torus joint which is standing at the top of the edge of the tank. This 
> joint is placed under pressure from the top cover which is bolted to 
> the tank using threaded rod which have been pre-assembled into the tank.
>
> This principle is currently not working efficiently and we must find 
> the root cause of the issue. The first thing we observed is that most 
> of the theaded rod are getting bent or unlocked from the tank. They 
> are currently based on stainless steel a strong material with a 3 mm 
> diameter.
>
> We used also specific glue to lock them down into the hole which was 
> threaded.
> The top surface of the tank edge has been post processed to be 
> flatened as much as we could.
>
> Roughly the assembly process is the following one:-
>
> - Solder the tank side to each other
> - Solder the bottom
> - Post process the edge of the top surface of the tanke to flaten it
> - use CNC to create 3D torus joint placement area
> - Put the thread rod in place
> - Run the whole assembly
>
> Looking at some math, when we put the tank under vacuum, I believe 
> that the pressure on the top cover is slightly moving to 1kg/square cm 
> as the pressure inside the tank is going to 0.007 bar, which means 
> about 1.4 tons for the whole cover. This pressure is transferred in 
> some way to the tank edges, and stainless steel elasticity is 
> exercising a strong force on the threaded rod which are breaking there 
> glue link and create some small leakage.
>
> I might be totally wrong, and this is where I need your help !
>
> We urgently need to have a look to this issue, as I would like to 
> upgrade asap this design flow. The following options might be explored 
> and will be discussed with some of our manufacturing partners this 
> week like:
>
> - Embedding the threaded rod during the panel manufacturing process 
> rather than gluing them
> - Use higher diameter and longer threaded rod
> - Put one at each corner (currently there is none, and most of the 
> leakage are observed in that place)
> - Put them in a Z shape around the 3D torus joint instead of a 
> standard aligned position
> - Increase the number of Threaded rod
> - Use bolt with wide pressure area (we are using standard 3mm bolt, 
> perhaps using 3mm hole bolt but 6mm contact diameter surface might be 
> better)
> - We could also increase the thickness of the top cover, but what will 
> be the right one ?
>
> I like to avoid increasing the thickness of the tank panel (which will 
> increase the contact surface with the top cover), as it will lower 
> heat exchange capacity.
>
> Feel free to jump into the discussion ! JJ will try to run some static 
> mechanical simulation tomorrow with solidworks as to understand how 
> much pressure each threaded rod have to address. But we are not expert 
> in mechanical simulation and if you have some options to help us feel 
> free !
>
> Jm
>
> -- 
>
> Â  Jean-Marie Verdun
> Â *Splitted-Desktop Systems*
> Â  President
> Â  Batiment Aristote
> Â  Parc des Algorithmes
> Â  Route de l'orme des merisiers
> Â  91190 Saint Aubin FRANCE
>
> Â jean-marie.verdun at splitted-desktop.com 
> <mailto:jean-marie.verdun at splitted-desktop.com>
>
> Â
>
> 	
>
> Splitted-Desktop Systems is a proud member of the Open Compute Foundation
> and a Gold member till July '15. We can provide you consulting and 
> engineering
> services related to any OCP hardware. We also drive RuggedPOD and Daap 
> Open
> Hardware projects
>
>
>
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-- 

   Jean-Marie Verdun
*Splitted-Desktop Systems*
   President
   Batiment Aristote
   Parc des Algorithmes
   Route de l'orme des merisiers
   91190 Saint Aubin FRANCE

jean-marie.verdun at splitted-desktop.com

	Splitted-Desktop Systems is a proud member of the Open Compute Foundation
and a Gold member till July '15. We can provide you consulting and 
engineering
services related to any OCP hardware. We also drive RuggedPOD and Daap Open
Hardware projects

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