miken
Part of the e-furniture
Posts: 481
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Post by miken on Sept 5, 2011 21:20:31 GMT
Has anyone ever considered using a small commercially made ball valve as a regulator in a 5" gauge locomotive? Did it work? it would have to be a 90 degree type. Does such a thing exist? Mike
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peteh
Statesman
Still making mistakes!
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Post by peteh on Sept 6, 2011 0:08:38 GMT
One of our members has used a gas ball valve in exactly that way. Certainly works well. Not sure if I have any pictures though. Lever on cab floor with push rod to valve in smokebow from memory. Speed proportional to extent lever is pushed forward. Only saw the engine once, about 4 months ago so my memory may be out
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Post by Jim Woods on Sept 6, 2011 3:48:36 GMT
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Post by Jim on Sept 6, 2011 5:14:50 GMT
I intend fitting a ball valve regulator in the smoke box of Boadicea in place of the poppet style regulator shown in the plans. If you intend fitting one you may need to test it in steam on a rolling road first as a good friend of mine found the PTFE valve seats expanded to the point where the valve wouldn't open luckily as it would have been serious if it had been the other way round. The problem was soon fixed by disassembling the valve and skimming a few thou from the seats. Since then it has worked perfectly. The with the valve I intend using the seats are easily adjusted by tightening or easing the retaining ring that can seen in the photo. Jim
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Post by Boadicea on Sept 6, 2011 7:49:54 GMT
Has anyone ever considered using a small commercially made ball valve as a regulator in a 5" gauge locomotive? Yes, Mike we have.... My mother told me water boils at 164 deg C at 100 psi and stainless steel is a better bet than brass inside a boiler. Therefore, maybe, just maybe, this ball valve would be suitable - with a temperature rating of 230 deg C. Just a thought - and willing to be shot down in flames!. Much talk of regulators in full thread here. Being older and wiser now, maybe the brass will do - they are dirt cheap and could be treated as a disposable item if difficulties are encountered, providing it is easily accessible.
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pault
Elder Statesman
Posts: 1,497
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Post by pault on Sept 6, 2011 12:00:54 GMT
Hi All I have retro fitted a number of 7 1/4” locos with these ball valves, the oldest one has probably been in service for about 8 years and is showing no signs of distress. The valve gives a nice gradual regulator, unfortunately they only do it in ½” BSP which might be a bit big for 5” gauge. www.vip-ltd.co.uk/dynamic/viewitem.php?item=01/0094/015Regards Paul
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 6, 2011 21:46:53 GMT
why build loco using plumber's fittings? why build a loco at all unless it is going to be a faithfull reproduction of the full size thing?! regulators arent rocket science!
however each to their own, though i gain much pleasure in making all the bits myself and making them as near to the fullsize as possible.
one point i would make is that most miniaature loco regulators leak, and some thought needs to be given to how to blank them off to ensure compliance with the current boiler regulations, and a lot of the published designs fail miserably in this respect. i can easily blank off the steam circuit from the regulator in the smokebox in my locos except one.... i have a Clarkson 3 1/2"g GWR KING being rebuilt and i dread to think how i am going to blank off the connections if the regulator leaks on it in 4 years time or so. the first re-test of the boiler is easy during the re-build as the boiler is out of the frames and without the smokebox. but later on...urg!! (no plumber's fittings on any of my locos especially THE KING!)
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miken
Part of the e-furniture
Posts: 481
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Post by miken on Sept 7, 2011 9:28:35 GMT
Thanks for the replies,Very interesting. MN
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pondok
Part of the e-furniture
My 5" gauge SAR class 15F
Posts: 359
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Post by pondok on Sept 7, 2011 9:38:52 GMT
Hi, I don't think anyone would dispute that the ideal regulator is a faithful reproduction of full size AND also works reliably, smoothly, with a complete seal when closed, but of course as you intimate jma1009, very often you have to choose one or the other. Many model engineers being practically minded, and knowing the regulator will be entirely out of sight in the smokebox or dome for most models, the benefits of the ball valve outweigh any consideration of what the component might look like. There is a growing consensus that the ball valve is unbeatable in operation, with those most desirable of features: - full close to full open through 90 degree movement - very little friction resistance thanks to the ptfe seat - allows closer to scale rods and handles to be used - good control in opening - the effect of one circular opening crossing another -positive seal when shut - avoiding dismantling smokebox fittings to blank off for hydraulic tests
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pault
Elder Statesman
Posts: 1,497
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Post by pault on Sept 7, 2011 12:56:03 GMT
Hi All “why build loco using plumber's fittings? why build a loco at all unless it is going to be a faithfull reproduction of the full size thing?! regulators arent rocket science!”
Simple because it won’t work if you just scale down a loco entirely. You can’t scale fire, coal, water, oil, steam, soot, material strengths, corrosion, mass, volume etc etc. So if you made an exact miniature copy of the full size thing you would be lucky to get it in steam let alone run it. So what’s the difference between fitting non scale tubes to a boiler so it will steam, it’s not a faithful reproduction, and fitting a ball valve inside the boiler?
The other thing is if you have one loco to look after and nothing else to do the maintaining a faithful copy may be fine. However If you have limited time or a number of locos to maintain things like plumbing fittings make life a whole lot easier. I have struggled to get main steam pipes out of a smoke box because they had flanged joints held together with 6 BA bolts because the heads had wasted due to corrosion. Most of the time plumbing fittings will come apart especial if they were put together with copperslip. Even if you end up destroying them a pound or two will get you back in business. Time is the thing I am shortest of, so plumbing fittings work for me.
Regards Paul
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Andrew C
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Post by Andrew C on Sept 11, 2011 8:24:13 GMT
Hi mike
I have only just noticed this thread. I like Jim have a 5 ins Brit under construction. Unlike Jim mine is an incomplete Model works kit. The Brits (modelworks) were I think ALL were supplied with commercial globe valves. Mine was missing but a trip into Anglian Hose and Hydraulics in Colchester soon fixed that. I know that John J. Has run his ModelWorks Brit quite a bit without any problems that he has mentioned on his website
There must be somewhere local to you that sell these.
Andrew
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Andrew C
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Post by Andrew C on Sept 11, 2011 8:33:56 GMT
Hi mike I have only just noticed this thread. I like Jim have a 5 ins Brit under construction. Unlike Jim mine is an incomplete Model works kit. The Brits (modelworks) were I think ALL were supplied with commercial globe valves. Mine was missing but a trip into Anglian Hose and Hydraulics in Colchester soon fixed that. I know that John J. Has run his ModelWorks Brit quite a bit without any problems that he has mentioned on his website As for 90 degree they do exist but straight one are fine, assuming it's not going in a terrier! Or something with next to no smokebox. I don't know how you would fit one that is inside the boiler. I would be concerned with electrolyse (different metals and water) There must be somewhere local to you that sell these. Andrew
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jonm
Member
Posts: 9
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Post by jonm on Sept 11, 2011 18:26:42 GMT
Hi Craigaj2 (Andrew) I managed to buy my gas valve from B & Q. It was approved for use with steam, It was 10mm or 8mm - I cant remember.but fitted my steam pipe which is all that matters. They work pretty well and in a discussion with Doug Hewson , he confirms they are excellent valves but did make the point that they need robust roding and a UJ linkage with no play between valve and smoke box gland - not always easy to arrange. I think we can accept that the gas valve is the answer for the Brit regulator but arranging the roding inside the smoke box from valve to smoke box gland needs careful work.jonm
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Andrew C
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Post by Andrew C on Sept 11, 2011 21:18:08 GMT
I had looked in B&Q. But obviously in the wrong section. This hobby is like choosing a new car. You find one you like and think there are not many of those about so you buy it. When you drive off the forecourt one up the road every fourth oncoming car is the same as the one you just bought . Have a look at the Station road steam site there staffod design uses commercial pluming fittings Andrew
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