[Ocp-europe] RuggedPOD v2 sealing feedbacks and improvements

Jean-Marie Verdun jean-marie.verdun at splitted-desktop.com
Tue Jul 7 20:54:34 UTC 2015


Hi Bill,

Thanks for the feedback. I do not think that the aluminum will be a cast 
plate but more an extra flat extruded plate based on aluminum ALPLAN.

You are right I think we need alignment pins to avoid the damage you 
mentionned. JJ our mech community member might have a look !.

Regarding double O-Ring, we can check, but as we plan to use PTFE O-Ring 
they might be strong,

Jm

ps: we need you in Europe ;), the closest POD from you will be in Irvine 
in about a month.

Le 07/07/15 22:46, Carter, Bill a écrit :
>
> I’m assuming that the aluminum is a cast plate.   Does the heat 
> transfer property change (gets worse) with cast Aluminum?
>
> As I recall from experience in my own garage building race vehicles, a 
> machined surface transfers heat better.
>
> The O-ring design is exactly what I envisioned – nice work! Again, 
> from my racing experience, an O-ring design can benefit from alignment 
> pins to keep the plates from shifting during assembly and avoid 
> potential tears or damage to the o-ring.    If you are concerned with 
> loads, maybe look at a double O-ring option that can be tested during 
> the next prototype build.
>
> Bill
>
> *From:*ocp-europe-bounces at lists.opencompute.org 
> [mailto:ocp-europe-bounces at lists.opencompute.org] *On Behalf Of 
> *Jean-Marie Verdun
> *Sent:* Tuesday, July 07, 2015 12:45 PM
> *To:* ocp-europe at lists.opencompute.org; team at ruggedpod.qyshare.com
> *Subject:* Re: [Ocp-europe] RuggedPOD v2 sealing feedbacks and 
> improvements
>
> 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>
>     [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
>     <mailto:jean-marie.verdun at splitted-desktop.com>;
>     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:* 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 
> <mailto: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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-- 

   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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