paul
Member
Posts: 8
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Post by paul on Dec 18, 2006 21:07:29 GMT
This decent little leaflet was posted in the stationary engines section by billj pump: (it's a pdf BTW) www.green-trust.org/junkyardprojects/FreeIC&ECEngines/ModelBoilers.pdfOn page 15 is a simple safety valve - does anyone have an opinion on this type of valve? If it's familiar to anyone here can you tell me what the arrangement is at the 'business end' - it looks like a ball bearing with guide rod much like others I've seen but being of open construction it might be easier to see that it's made/working properly. TIA |
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Post by baggo on Dec 18, 2006 21:59:20 GMT
Paul, The large drawing of the valve does not show a centre pin, just the spring holding the ball in position, although the earlier drawing of the valve on the boiler would appear to have the pin. I certainly would not recommend making one of that design unless fitted with a centre pin which is actually attached to the ball, e.g. threaded into it. Otherwise the ball may flirt out completely if there is a sudden increase in pressure with possible dangerous consequences i.e. emptying the contents of the boiler rather rapidly!  Personally I think you would be better using the more common enclosed type of valve as fitted to most boilers and locos. The escape of steam from those is also in a vertical direction rather than sideways which is probably safer.I would think the type of valve in the article is actually more difficult to make. The enclosed type are just relatively simple turning jobs. Just my opinion, John |
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Myford Matt
Statesman
There are two ways to run a railway, the Great Western way, and the wrong way.
Posts: 621
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Post by Myford Matt on Dec 18, 2006 22:43:22 GMT
Interesting - there are other 'ebooks' there of interest - nice one on slide valves.
Thanks
Matt
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Post by steamjohn248 on Dec 19, 2006 21:28:43 GMT
Don't think much of the boiler testing advice either, "use compressed Air!!!!!"
Steamjohn
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jackrae
Elder Statesman
Posts: 1,335
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Post by jackrae on Dec 20, 2006 7:40:09 GMT
I would estimate that this e-book is somewhere in the order of 50 to 60 years old, judging by the style of the drawings and the blow-lamps!
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paul
Member
Posts: 8
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Post by paul on Dec 20, 2006 8:53:36 GMT
It's older than that - early 20th C I think. But then so are many steam engines!  |
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Post by chris vine on Dec 20, 2006 18:53:16 GMT
Hi Paul,
Please stop winking at me!!!!!!!!
Chris.
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Post by Phil Sutton on Dec 20, 2006 20:17:13 GMT
Paul ,that eye is a bit unsettling-are you sure it isn't suffering?
Phil
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paul
Member
Posts: 8
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Post by paul on Dec 20, 2006 20:18:48 GMT
Re the eye: it must be whoever is behind this board!
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Post by Shawki Shlemon on Dec 21, 2006 9:44:48 GMT
I fully agree with John. best way to go .
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Post by chris vine on Dec 21, 2006 10:30:59 GMT
Which way was that?
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Post by ron on Dec 21, 2006 10:44:01 GMT
Guys
Surely there's an error in the drawing, there should be some sort of guide pin or as John says the ball could shoot out all together and having had the centre blow out a modern type safety valve under pressure [don't ask!] it's not much fun! Stuart Turner used to fit that type of SV to their boilers [with guide pin] before the war but they've used the modern enclosed type for years, maybe that says it all.
Ron
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Post by gilesengineer on Dec 21, 2006 17:25:33 GMT
I rather suspect that it may not be a ball, but rather a cone seat or similar - which may well have a guide rod going down into the valve, rather than up (it would make re-seating a great deal more reliable). However, whichever way you look at it, its a rather dodgy bit of kit, and not what I would be comfortable sitting behind.......
(Happy Christmas to everyone!)
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paul
Member
Posts: 8
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Post by paul on Dec 21, 2006 17:37:58 GMT
OK all, the educated opinion is a resounding 'forget it'... I hear ya!
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