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Post by flyingfox on Jul 29, 2015 7:02:19 GMT
Greetings
Can anyone please direct me to a drawing of a steam Vacuum Ejector, suitable for large 5" or 7 1/4 " gauge?
I did have one but the little man under the bench must have it at the moment.
Thank you
Flying Fox
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Post by ejparrott on Jul 29, 2015 8:11:21 GMT
I'm pretty sure there's one in Derek Brown's book but unfortunately I've not currently got it so I can't show it you.
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Post by flyingfox on Jul 29, 2015 16:08:51 GMT
Yes there is, found it.
Many thanks
BB
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mbrown
Elder Statesman
Posts: 1,719
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Post by mbrown on Jul 29, 2015 16:10:21 GMT
There are drawings and various cone sizes in the articles by Brian Hughes in the ME in 1965 - these original articles were reprinted some years later but I don't have the dates for that.
For a more-or-less scale ejector for LMS or LNER locos, see Don Young's designs for the "Crab", Black 5 and "Doncaster" (A3) - all in 5" gauge - in his Locomotives Large and Small. I am not beside my bookshelf right now but if you are interested in these drawings send me a PM and I'll post you copies. These are good representations of the Midland/LMS ejector mounted on the side of the boiler and the Gresham and Craven 2-cone ejector as used by Gresley in the cab. They are probably quiet complex to make....
Malcolm
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Post by Deleted on Jul 29, 2015 21:41:41 GMT
Hi This is the ejector valve as drawn by Don young for his 5" Doncaster  hope it's of use.. Pete |
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Post by flyingfox on Jul 30, 2015 6:55:00 GMT
Greetings, thank you for all the information provided.
I have a scale 7 1/4 Britannia ejector fitted, but it is only pulling about 5 " Hg, and I was looking for cone sizes to try & improve it.
I think DAG Brown's book has the best info & I will try that first.
Regards
BB Flying Fox
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Post by ejparrott on Jul 30, 2015 8:46:28 GMT
Scale 7.25" Britannia only pulling 5"Hg??? There's something wrong with that!! Hewson's 5" ejector draws 21"Hg no problems
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Jul 30, 2015 9:25:49 GMT
hi brian,
i agree with Ed.
i would be inclined to have a good look at the gadget you already have and test it on air with a decent vacuum gauge. some of the miniature vacuum gauges are not very good. there may be a leak on the vacuum side somewhere.
there is quite a diversity of different cone shapes and lengths and sizes in the miniature designs for the ejector itself, being nothing like so critical as injectors. so for example Don Young's Doncaster big ejector (shown above by Pete) and Martin Evans' Stratford ejector have a smaller steam jet than Derek Brown's, and a larger exhaust jet size than Derek's plus a larger gap between the 2 cones. the original Brian Hughes /Reeves design is the same as Stratford and which i have used with great success. the internal shape of the cones is not as simple as that used by Derek Brown.
so there is plenty to choose from and experiment with!
just be aware that the type of cones shown by Don Young are extremely difficult if not impossible to remove without damage - or at least removing the first of the cones will be as they are a press fit.
cheers,
julian
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