Alan
Part of the e-furniture
Posts: 285
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Post by Alan on Jan 15, 2005 13:40:57 GMT
has anybody got to the vacuum pump yet. How have you overcome it?
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Post by Andy Clark on Jan 24, 2005 16:54:27 GMT
Sadly not nearly that far yet.
Andy
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Post by Rex Hanman on May 5, 2005 12:10:33 GMT
One day
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taff
Hi-poster
President of City of Newport M.E.S. Chairman, Rivet Counters Fellowship.
Posts: 161
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Post by taff on Nov 30, 2010 16:34:02 GMT
Hello Alan, I am not able to claim construction of a vacuum pump for the 51xx 2-6-2 tanks but I have made a couple for other G.W. models. The G.W pump appears to be a standard design for all of the engines but simply enlarged or lengthened to suit the size of loco. I assume that your main worry concerns the inlet and exit valves at each end of the pump. I solved these on mine by making the valves out of a hard rubber. I don't know what the design of your pump is like but if it follows full size practice there are two valves, one above the other, at each end of the pump barrel and they are connected by a channel running along the top of the pump body. The inlet connection from the train pipe and the limit valve( "pepper pot" ) are both attached to this channel. I had to make special moulds to maked the rubber valves but these were straight forward turning jobs which could be made in a few minutes. I found that the rubber valves worked very well. I am currently making patterns for a lost wax casting for a combined vacuum/water pump which was fitted to some of the earlier Dean designed loco's but if you can give me a few days I'll post a few drawings in the forum which maybe of help. I'm currently building some "Saint" class engines and have to make the vacuum pumps for these.
Taff.
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Alan
Part of the e-furniture
Posts: 285
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Post by Alan on Dec 16, 2010 11:08:48 GMT
thanks Taff
I have put the Prarie in the projects corner of the workshop for a while. it was becoming a constant headache, not just an occasional one.
Thanks Alan
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Post by Laurie_B on Jan 15, 2011 13:24:24 GMT
Having acquired an 'abandoned project' recently,I've been making up some the brackets for the running boards etc and seem to have found an error in the drawing for the vacuum pump bracket. Drawing sheet T7 shows the mounting flange width as 1-7/64" which,I find is not wide enough.Looking at drawing T6,it would appear the width should be nearer 1-7/32".Then the all various bolt holes (including those for the weighshaft brackets) should line up,I am hoping. Below is photo of the bracket set up on the right hand frame to mark out the bolt holes,when the error was discovered. Attachments:
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Post by fostergp6nhp on Oct 16, 2011 12:03:20 GMT
Full size the train pipe is connected to the retaining valve and the pump is connected to that, with another port on the RV connected to the vac cylinder resevoir, when the brakes were applied the plunger in the retaining valve lifted and the train pipe to pump connection became shut off and the pump became connected to the vac cylinder resevoir. Result there is no loss of vacuum in the res side of the brake cylinder so even with a lot of slack in the brake gear the power is not diminished.
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Post by Laurie_B on Oct 17, 2011 16:14:54 GMT
I found this diagram of a GWR vacuum pump in,shall we say,a publication on GWR matters. Also I was wondering what other builders have done or have in mind.I was thinking about making this a crosshead driven boiler feed pump rather than a vacuum pump. Hope the diagram is of interest. Attachments:
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Post by dinmoremanor on Oct 23, 2011 21:15:15 GMT
I'm after a vac pump casting for my Manor, does anybody know of someone who supplies one before I end up fabricating something? Reeves don't seem to supply one for the 51XX
Cheers,
Mike
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Post by Laurie_B on Oct 24, 2011 9:41:22 GMT
Hi Dinmore Manor The only vacuum pump casting that Reeves list is for Keith Wilson's Bulldog/Dukedog designs.Not sure it is entirely suitable,but if it is I'm thinking of using this on my 5"gauge 5101. Maybe Polly Model Engineering/Practical Scale have or are planning something suitable?
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Post by dinmoremanor on Oct 24, 2011 16:46:46 GMT
Hi Laurie,
Cheers for that, I have tried Practical Scale and as of yet it is not in their range, The Bulldog casting from Reeves might be worth a look though likely to be a little short on the stroke, might see if I can call in there and measure one up seeing as I am local
Cheers,
Mike
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Post by fostergp6nhp on Oct 24, 2011 20:30:12 GMT
My plan for the 5101 vac pump was to use 2 bulldog pumps cut and shut by silver soldering to create one long enough for the longer stroke.
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taff
Hi-poster
President of City of Newport M.E.S. Chairman, Rivet Counters Fellowship.
Posts: 161
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Post by taff on Oct 25, 2011 23:51:51 GMT
Helllo folks, I had a pattern for the vacuum pump for 5" gauge GW engines and have passed it to Pete Thomas at Polly some time ago. I am not sure how close he is to making castings available for it. The original is for a model of a "Saint" class which I am building.
Taff.
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Post by donashton on Oct 28, 2011 15:18:21 GMT
How very interesting, since I and others (including Pete Thomas) need one of these in full size!
Don
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Post by Shawki Shlemon on Nov 1, 2011 7:30:45 GMT
When I got my castings for the Manor , they included a cross head pump which I made for water feed , it works fine , I sold the engine few years ago , I saw the engine two weeks ago in our club special run day and the pump was still working well , no supplementary water was needed during few hours of run .
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