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Post by Deleted on Jul 24, 2014 8:03:35 GMT
When Alan kindly gained me access to the workshops at SVR, he showed me an arrangement they have there where a locomotive could be arranged to sit over a removable section of rail on one of the inspection pits. I suppose you could have a sturdy raised rail with as few supports as possible, and then have one or more sections that you could remove. That way you could leave it on its wheels and still remove an axle or have unobstructed access to the springs for example. ---------------------------- It's called a Wheel Drop >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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Post by Deleted on Jul 24, 2014 8:16:05 GMT
Hello all------------I would add my support to "young" Mr. Parrot's design as I've seen the same principle used on various industrial applications eg}--- Army Rolls Royce power packs through to the coolant system on my 1975 Honda GL1000 Gold Wing motorcycle............I think that 2 or even 3 thin o rings per head is preferable to achieve a constant seal rather than the single large one, and to allow for mis-alignment...--------------------------------------
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Post by Roger on Jul 24, 2014 8:25:27 GMT
I'd say the opposite is true for accommodating misalignment.... one large one is better. Also, one seal is plenty. If one's going to leak then so will a dozen. Get the right amount of compression and it will never leak.
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Post by Deleted on Jul 24, 2014 10:21:33 GMT
Sorry to disagree ROGER, but experiences in many disciplines has shown that multiple "fingers" contacting a surface can accommodate any mis-alignment much more effectively than just the one........... Some Steam Turbines have a multi-contact seal on the end of the mainshaft, the LMS ROYAL SCOTs' famously had their piston valve rings increased in number to overcome leakage,-----------------------
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Post by Deleted on Jul 24, 2014 10:58:44 GMT
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Post by Roger on Jul 24, 2014 16:50:15 GMT
Sorry to disagree ROGER, but experiences in many disciplines has shown that multiple "fingers" contacting a surface can accommodate any mis-alignment much more effectively than just the one........... Some Steam Turbines have a multi-contact seal on the end of the mainshaft, the LMS ROYAL SCOTs' famously had their piston valve rings increased in number to overcome leakage,----------------------- Hmmm.... not quite the same situation though is it. This is not a moving part, it's just a simple unmoving seal. A larger section 'O' ring will accommodate more misalignment for sure. Imagine a 1mm section one or a 3mm section one in the same situation. The compression % is the same so the amount they can accommodate in misalignment increases as the section goes up. Move a 1mm section ring sideways 0.2mm and there is no contact on one side. Contrast that with a 3mm 'O' ring, that has to move 0.6mm to get to the same point. In a static seal, you don't expect to get any leakage, unlike the situations where it's moving. You can't use the same reasoning, the conditions are different.
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uuu
Elder Statesman
your message here...
Posts: 2,809
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Post by uuu on Jul 24, 2014 18:15:13 GMT
The Space Shuttle had two seals. Still crashed.
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