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Message No. 13832, Started by bqtran on 05/05/04
 Vacuum Chamber Design I'm working on a project fixing a vacuum chamber.  This is a regtangular chamber with a cross section of 6ft wide x 7'-4" high. The chamber length is 18 ft. The chamber shell is 1/4" thick plate and is reinforced with 3x3 11 ga. tubes all the way around at 20.5" spacing. All materials mentioned are 304 SST. The chamber operates at 28" Hg vacuum with a load of 24,000 lbs evenly distributed on the chamber floor. After a period of time, the chamber floor has experienced very noticeable and permanent deformation. To be specific, the floor curves up a significant distance.  Additionally, the welds along the longitunal corners have cracked at many places. We're going to replace the floor completely. The new floor will have stronger 4x4x1/4 tube bracing on the bottom. Also 3x3x1/4 angles will be welded at inside corners of chamber.  Anyone with experience in designing vacuum chambers please advice areas of concern? I'd appreciate your suggestions to fix the problem.
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Follow-up Messages (16)
 bury it lengthwise in the ground, even 1 or two feet deep will do it, I tho... No. 13870, Posted by gerdb on 05/08/04, 09:09 PST. that's the way its done looking for answers and the avoiding them, wha... No. 13867, Posted by gerdb on 05/08/04, 08:46 PST. Hi Gerdb , I'm surpraised with your answer . Are you kidding us? Up to ... No. 13865, Posted by devitg on 05/08/04, 07:58 PST. yes because the wall is the most charged element. Since all sides are simi... No. 13863, Posted by devitg on 05/08/04, 07:45 PST. make a round pipe, burry it 1/3 in the ground and you have your floor where... No. 13862, Posted by gerdb on 05/08/04, 03:53 PST. does someone else see the symbolism ? No. 13861, Posted by gerdb on 05/08/04, 03:28 PST. Right - but the floor is only 6' wide. That's where we differ. You're tal... No. 13858, Posted by acroduster1 on 05/07/04, 19:15 PST. >I don't know where you get the 258000 lbs. It is the walls load. It is e... No. 13854, Posted by devitg on 05/07/04, 10:58 PST. I just checked the numbers, devitg, and I'm not coming up with what you got... No. 13853, Posted by acroduster1 on 05/07/04, 06:54 PST. Hi Acroduster , as you can see in my previous post the load does not help a... No. 13848, Posted by devitg on 05/06/04, 13:29 PST. Sir, Thanks for your comment and suggestion. One thing I forgot to menti... No. 13847, Posted by bqtran on 05/06/04, 12:28 PST. I've done large high velocity process air ducts that pull a vacuum, althoug... No. 13844, Posted by acroduster1 on 05/06/04, 04:32 PST. It may be a lot cheaper and certainly safer to design a new chamber using a... No. 13839, Posted by gerdb on 05/05/04, 16:47 PST. as the welding load is about 434 lb-inch length , it is distributed on th... No. 13836, Posted by devitg on 05/05/04, 13:54 PST. Sir, Thank you for the analysis. Please clarify how you came up with loa... No. 13835, Posted by bqtran on 05/05/04, 12:59 PST. ASME CODE SECTION VIII DEAL WITH VESEEL UNDER EXTERNAL PRESSURE. You sha... No. 13834, Posted by devitg on 05/05/04, 12:31 PST.