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Bulleid's 'Leader' class.

Discussion in 'Steam Traction' started by Eightpot, Mar 24, 2019.

  1. Eightpot

    Eightpot Well-Known Member Friend

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    Have been reading up on these locos (36001 - 3) over the last few days. One thing that puzzles me is that there are a number of photos of the sleeve valves, but none showing any grooves for the sleeve valves, and liner rings. So where/how were this multitude of rings fitted, also, how were the cylinder covers fitted, both front and back, and made steamtight?

    Anyone got a drawing of the cylinder arrangement to explain things?
     
    Last edited: Mar 24, 2019
  2. PoleStar

    PoleStar New Member

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    There is a drawing in "Bulleid of the Southern" page 138 although this is not very clear. In "Bulleid last giant of steam" p. 221 it is stated that the rings were fitted in the cast iron liners (i.e. the cylinder block liners) on the outside of the sleeve and were internally expanding., which would explain lack of ring grooves in the sleeves. It is not clear from the drawing how the cylinder covers were attached - so it's a good question.

    The rear cover appears to be of top-hat form with an external flange, bolted to the rear of the cylinder block in a conventional fashion, The rear end of the sleeve operated in the annular space between the tubular part of the cylinder cover and the cylinder block liner.

    I would guess that the front cover was similar as there was clearly a circle of studs on the face of the block, but the cover must have had slots to allow the lugs of the sleeve to project and connect with the operating gear.
    .
     
    Last edited: Mar 26, 2019
  3. decauville1126

    decauville1126 New Member

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    Might be of use around 1m 12secs, but the whole is worth watching.
     
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  4. Eightpot

    Eightpot Well-Known Member Friend

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    I presume that you mean 'internally contracting' for the valve rings. I'm not saying that there is no such thing for this type, just that the only such rings I have ever come across have been of the external expanding type. However, as (certainly some if not all) railway companies made their own piston rings, but in this case according to Kevin Robertson's book, they were supplied by Messrs. Wellworthy, so possibly they were indeed special internal contracting ones.

    Assuming that they were fitted in grooves in the pressed in cylinder liner, as the sleeve valves (from photos) do not appear to have any chamfers at the ends it would be interesting to know how the sleeve valves were fitted into the liners and through the rings.
     
    Last edited: Mar 26, 2019
  5. PoleStar

    PoleStar New Member

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    I was quoting what the book said! It would indeed be interesting to know how it was all assembled. Bear in mind that piston rings for steam are not the same as those for IC engines - they do not need to be as "springy" and tend to seal by steam getting into the groove and pressing the ring out against the cylinder. You can imagine the reverse happening if the groove was in the liner and the ring being pressed inwards onto the sleeve. It must all have leaked a bit until it warmed up!

    May we ask why you need to know - are you building a replica?

    The video is fascinating and shows among other things how much had to be fitted into a very restricted space.
     
    Last edited: Mar 27, 2019

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