[AR] Re: Updated custom ball valve

  • From: Robert Watzlavick <rocket@xxxxxxxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Mon, 30 May 2016 12:08:10 -0500

Thanks for the link. One thing I noticed in those types of valves (also see SP-8094) is they make use of bellows and other spring type devices to help compress the components.

-Bob

On 05/30/2016 11:09 AM, Paul Mueller wrote:

As Ben said, I think most if not all vehicle cryo valves have short stems. I doubt this is any help at all, but here's some info on the Space Shuttle main fuel valve: https://www.nasaspaceflight.com/2011/06/sts-135-crew-arrives-tcdt-mfv-work-begins-ssme-3/

On Mon, May 30, 2016 at 9:52 AM, Robert Watzlavick <rocket@xxxxxxxxxxxxxx <mailto:rocket@xxxxxxxxxxxxxx>> wrote:

    What kind of stem seal did they use?  Was it the type where you
    have a cone that squeezes into a sleeve?

    I hadn't seen any short stem cryo models. It might be worth me
    getting one to take it apart. Were these custom or off the shelf?

    -Bob

    On May 30, 2016, at 10:24, Ben Brockert <wikkit@xxxxxxxxx
    <mailto:wikkit@xxxxxxxxx>> wrote:

    To be clear, basically every vehicle I've worked on had short
    stem cryo ball valves, and most of them did not leak. Torque
    requirements are another issue, but it is not a universal truth
    that all short stem ball valves leak out the stem.


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