# Cylinder Drains with no moving parts - photo needed



## Mark Scrivener (Jan 7, 2008)

In the archives Kevin O'Connor describes an automatic cylinder drain with no moving parts. Unfortunately the pictures are no longer available and I can't follow his description without photos. Does anyone have a picture or a drawing of this mechanism? From the description it sounded much more compact and elegant for gauge 1 locos than the floating ball method. 

Thanks,
Mark


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## Chris Scott (Jan 2, 2008)

Email: [email protected]


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## Bob in Mich (Mar 8, 2008)

Mark,Try David at DJB Engr.He has them.


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## peter bunce (Dec 29, 2007)

Hi Mark, 


They are at the bottom of the page at the following link 

http://www.djbengineering.co.uk/index2.html


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## David Leech (Dec 9, 2008)

Posted By peter bunce on 30 Jan 2010 06:08 AM 
Hi Mark, 


They are at the bottom of the page at the following link 

http://www.djbengineering.co.uk/index2.html 


Hi Peter,
Actually it doesn't, you have to select the 'Live Steam Fittings' page, but I get the idea.
BUT these are the ones with balls in, are they not.
The question was for details of the one 'with NO moving parts'.
Can there be such a thing?
All the best,
David Leech, Delta, Canada


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## Steve Shyvers (Jan 2, 2008)

Kevin's design features a horizontal rod that is a loose fit between two spigots fitted to the bottom of the cylinder at each end. "Loose fit" in this case means about a 0.002" clearance between the ends of the rod and the holes in the spigots that it sits in. The ends of the rod were also shouldered, I believe. I do not remember what the fore and aft play of the rod was. In operation the device slowly leaks condensate, but the condensate also serves to block the passage of steam. At least this is what I remember from the past discussions on MLS. One MLS correspondent called it a variation of a "labyrinth seal". 

I would guess that clearances, steam pressure, cylinder volume, piston speed, steam oil consumption, and cylinder temperature would all be design factors. Kevin's example was for a Ruby, which should provide a starting point for empirically-based experimentation. 

Steve


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## Mark Scrivener (Jan 7, 2008)

Hi Steve, 

Yes - this is the design I was referring to. Keven refers to "spuds" in his post - perhaps these were the spigots? He had also posted pictures and drawings, but they are no longer available. Your description of a "labyrinth seal" or a controlled leak where the steam condenses in the passageway and the condensate serves to block steam sounds like it. He apparently fitted this design to a number of small engines, not just the Ruby. 

Did anyone else ever try to use this technique?


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## Steve Shyvers (Jan 2, 2008)

Hi Mark, 

I used "spigot" because I couldn't think of another term. Yes, they would be what Kevin called "spuds". 

Steve


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## Chris Scott (Jan 2, 2008)

Old thread pic of Kevin's Ruby


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## Mark Scrivener (Jan 7, 2008)

Thanks Chris! That makes it perfectly clear! 

Based on the descriptions I've read, the vertical "spigot" or "spud" has a central passage going into the cylinder. The horizontal cross pieces have approx 0.001" - 0.002" clearance. The horizontal pieces also appear to be slightly flared on the ends to prevent sliding out. I think I'll try these on my K-27 first since there is already a "spigot" going into the cylinder. If it works on the K then I'll try it on the others.


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## Chris Scott (Jan 2, 2008)

Mark 
Glad to help. Would have posted pic sooner if I could have found it 

Keep a diary with lots of pics.


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## Jack - Freshwater Models (Feb 17, 2008)

Anyone know of a drawing of one of these? 

Jack


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## Chris Scott (Jan 2, 2008)

Posted By Chris Scott on 31 Jan 2010 03:55 AM 
Mark 
Glad to help. Would have posted pic sooner if I could have found it 

Keep a diary with lots of pics. 


Mark:
I am particularly interested in how you get the factory drain cocks out (i.e., desoldered or ?), and what you have to do to prep the cylinders for the replacements (i.e., do the cylinders have to be drilled out and tapped?).


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## SteveC (Jan 2, 2008)

This may answer the question regarding drawings. The following quote is from a topic in the MLS archives.

Posted By: Kevin O'Conner
_"The "clear as mud" gentleman asked for "diagrams", but I have none to offer. I do all my designing and modifying in my addled head as the lathe and mill spin and hog. I commit very little but numbers to paper. In my former professional life I lived by the adage that "He who plans ahead will do his work twice" because things in my circle of influence changed so rapidly. Here it is a little different, but I have so little time to devote to my hobby that I don't want to take time away to provide documentation."_ Live Steam Forum/Topic: draincocks - how important? (page-2)[/b]


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## Mark Scrivener (Jan 7, 2008)

Chris, 

I'm thinking I might not have to remove the factory "spigots" - but simply fashion a proper cross piece to go in the factory spigot such that it forms a labyrinth seal. 

If I have to remove the factory "spigots" I'm guessing they are threaded in....


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## Chris Scott (Jan 2, 2008)

Posted By Mark Scrivener on 02 Feb 2010 10:03 PM 
Chris, 

I'm thinking I might not have to remove the factory "spigots" - but simply fashion a proper cross piece to go in the factory spigot such that it forms a labyrinth seal. 

If I have to remove the factory "spigots" I'm guessing they are threaded in.... 
I've heard and been told they are soldered and it may be soft solder. I have a junk pair of cylinders, well not quite junk, they have a project target, but it's been a target for I forgot how long. So maybe I'll go tear a drain cock out of one and see what happens. I'll get back to you.


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## maculsay (Jan 2, 2008)

Posted By Mark Scrivener on 30 Jan 2010 09:06 PM 
Thanks Chris! That makes it perfectly clear! 

Based on the descriptions I've read, the vertical "spigot" or "spud" has a central passage going into the cylinder. The horizontal cross pieces have approx 0.001" - 0.002" clearance. The horizontal pieces also appear to be slightly flared on the ends to prevent sliding out. I think I'll try these on my K-27 first since there is already a "spigot" going into the cylinder. If it works on the K then I'll try it on the others. 

Hi Mark.

Have you been successful with making your own automatic draincocks, ala the Kevin O'Connor Spuds?


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## cjsrch (May 29, 2010)

seems to me that if you used two different metals that once the hotter steam began to escape they would expand slightly and form a better seal. 
i dont see how water the thing you want to drain is also going to act as a plug.


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## RimfireJim (Mar 25, 2009)

Posted By cjsrch on 01 Nov 2010 04:10 PM 
seems to me that if you used two different metals that once the hotter steam began to escape they would expand slightly and form a better seal. 
i dont see how water the thing you want to drain is also going to act as a plug. 
I think if you do the calculations for thermal expansion you will find that, for the dimensions and temperature differences involved, any differential expansion will be so minute as to be completely negligible. The calculation itself is quite simple: change in dimension=dimension X coefficient of thermal expansion (material physical property) X change in temperature. Or, for two materials with the same nominal dimension and temperature change, change in clearance=dimension X (c.t.e. mat'l 1 - c.t.e. mat'l 2) X change in temperature. Just make sure to use the same temperature units throughout.


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## cjsrch (May 29, 2010)

hehe < .000001 inches. 
forgot about the size of what wer are working with


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## Two Blocked (Feb 22, 2008)

Wow! Thanks Chris! I'd forgotten all about that photo! It's busier than I had remembered. That's an Accucraft headlamp from one of their prototypes via their junk drawer, the diamond stack is from a Chaney Heisler, the dynamo and Roscoe (dead leg) steam oiler are from a Frank S., and the crosshead and guide are home grown. The steam drains shown are about third generation creations. Steve is right about the first generation models having a "rod" that extended from spud to spud. At first the rod was drilled cross-ways with the centerline of the spuds, and was manually rotated via a lever arm to line up with through holes in the spuds to drain the cylinders. This is about the same system that Aster and Accucraft use today. I never much liked the system because I could not get to the "other side" to easily see what I was doing. Next came the "shuttle cock" system that much looked like the original in as far as there was a rod that spanned the spuds, but instead of lining up cross drilled holes in the rod, the rod had an annular grove cut into its diameter, that when pushed to and fro, lined up [or not] with the holes in the spuds, and thus drained the cylinders. This system worked out better on the "other side" because all I had to find was the end of the rod and push it either fore or aft to make it open or close the drain. I wanted something better, and so I created the first Unit Shop cylinder drain design with no moving parts. Steve is right again. The two spuds [per cylinder] were cross reamed to a 1/16" undersized diameter, and the spanning rod's ends were turned to a diameter .001" to. 002" smaller in diameter than the reamed cross holes in the spuds. The middle of the rod was left mill size so the rod could not work their way forward or astern during operation, and the drain holes through the centerline of the spuds was left always open to the atmosphere via the one to two thousands of an inch clearance around the spanning rods. 
Here's the theory. Upon opening the locomotive's throttle valve, the steam in the boiler starts to cool and condense on its way to the cylinders. The cylinder's fill with condensate [water] and lock up. At this point cylinder pressure and boiler pressure are the same. Boiler pressure starts to force cylinder condensate down through the center drain holes in the spuds, and enters into the atmosphere via the tiny clearances around the ends of the spanning rods. Quickly, the cylinders drain out their condensate, fill with saturated steam, the locomotive starts to run, and cylinder pressures*drop*due to steam admission cut-off and steam expansion. At this point the drain valves self seal with a minor amount of condensate trapped in their passages, and will self drain again only when sufficient condensate builds up in the cylinder's head space. At this point the cylinder's pressure will start to rise to that of the boiler, once again repeating the first cycle. In practice the cylinders drain quickly, the loco trots around weeping a drop of condensate now and again, there is no loss of steam through the column of condensate still trapped in the spuds, and little or no condensate is ejected from the stack; even on alcohol fired locomotives that need intensive draft to fire properly . No steam is lost through the assembly. 
I wanted to get away from the spanning rod, and so next I tried the approach depicted in the photo. It's the same theory, same clearances, just that the rod is replaced with two collared inserts that fit into each other inside the spuds cross ream diameter. I thought that this approach was too complicated, and so I moved on to the present Mark-X iteration which I should have done in the first place. That is two spuds per cylinder, center drilled and cross reamed as before, with a cross stub rod with a .001" to .002" groove cut in its middle, loosely press fitted into the spuds. The length of the stub rod is the same as the spud diameter, and so in practice it looks exactly like the ones in the photo, but without the collars. I did drill a .020" diameter hole through the stub rods so that I could pass a pin gauge through a pair when I pressed the pair, all at once, into the bottom of the cylinders. I did this to line them up in the same orientation. Once each pair were in place, I removed the pin gauge. If I ever have to remove a spud in future, having those "construction holes" in place will be a plus during the removal process. 
There is another, Mark-,Y drain cock on the way. Harry Gray is building a brace of 1:32 LBSC Tichs, and I ordered one up nearly two years ago. He recently sent me the cylinders for mine because I want to add Unit Shop drain cocks before his final assembly. I also asked for smaller diameter cylinders/pistons than stock because, well, just because for now. So I am thinking of using this extra materiel around the cylinder bore to bury the drains inside instead of letting them hang out. I sorta did something like this a few years ago when I installed hidden cylinder drains [same principle] in the cylinder covers, not the cylinders, of an Accucraft Mogul. Stealth drains I called them. They worked well, but they are not for everybody. Think laboratory curiosity! 
Two months ago I delivered a Frank S. locomotive to Chuck Sanfillipo that I had built up from used, spare, and Unit Shop parts. The loco has many unique features, and one of them is a set of used [by me] cylinder assemblies that have the second generation, shuttle cock drains [circa 1997]. I offered to change them over to the latest Mark, but Chuck said "No thank you, I like playing with them just the way they are". I saw him just today at Paul Brink's home track, and he stopped to tell me again how much he likes the locomotive ....... just the way it is. 
The reason that all those previously posted photos are among the missing is that I'm no longer a first class member, and so all that old stuff I posted years ago went up in smoke when Chad, or Tad, or whoever pulled my plug. I'm anticipating some more hobby time next winter/spring, and so I'm considering re-upping; we'll see just how steady she goes. 
Hey Dwight! What ever happened to the "review" function on this site?


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## Dwight Ennis (Jan 2, 2008)

Hey Dwight! What ever happened to the "review" function on this site?If you're referring to what I think you're referring to, it too went up in smoke.


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## DKRickman (Mar 25, 2008)

Posted By Dwight Ennis on 02 Nov 2010 08:47 AM 
Hey Dwight! What ever happened to the "review" function on this site?If you're referring to what I think you're referring to, it too went up in smoke. 
Why? Did it get poor reviews?


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## Dwight Ennis (Jan 2, 2008)

Kevin's post copied from another thread per his request...
Posted By Two Blocked on 08 Nov 2010 09:56 PM 
Here are some photos of "automatic" steam cylinder condensate drains that will complement the discussion on this same subject that was a thread a week ago. I'm hoping that Dwight can tie the two together in the website's archive.
The first two photos are of my 0-6-0 Saxsonian that came from Accucraft with the quarter-turn valve shown. This was exactly the same design I started out with in 1997.










The originals were made of brass, and the actuating rod was cross drilled so that when the actuating rod was in the side position, as shown, the valves were closed. When the actuating rod was moved 90 degrees down (the cylinder head prevents movement in the other direction) the cross holes line up with the centerline drilled holes in the spuds, and the headspace of the cylinder is opened to the atmosphere. Once the condensate clears the process is reversed and the drains are closed.










Please notice that the actuating rod on the Saxsonian is wired in place in the closed position. This is so because I converted the manual quarter-turn valves into "automatic' type valves by machining the original stems to the third generation Unit Shop configuration (please see previous thread) and I did not want vibration to cause them to rotate to the old open position. In effect this is an example of models one (abandoned in place) and three.

I did not like dealing with model one because I had to reach over the locomotive to get to a lever that I could not easily see. The next step was to move on to the shuttle-cock design.










This set of Frank S. cylinder drains has been in use for 14 years and tens of thousands of scale kilometers without any kind of wear or failure. They are shown in the forward, open, position. I shot this photo today at Paul Brink's Monday steamup just before its present owner, Chuck Sanfillipo, fired it up for the day.











Now the shuttle-cock has been pushed back to close off the drains. Please look closely just aft of the spuds and you will see the .005" annular grooves cut in the shuttling rod passing through the spuds. These grooves, when lined up with the centerline holes in the spuds, allow the cylinder headspace to vent to the atmosphere. When they are cycled to the rear, the centerline holes in the spuds are sealed off.

We've covered models one (1/4 turn), two (shuttle-cock), and three, the static rod with two .001" annular grooves inline with the cylinder spuds (please see prior thread). Now let us move on to model four, the stand alone spud drain cock.










I copied this photo from the previous thread. The loco is my Ruby which dates from my association with the first Accucraft Rubys in 1997-1998. It too has a bazzilion miles on it, and has been the test bed for a lot of Unit Shop ideas. It once had model three condensate drains, but somewhere along the line it moved up to the first of the model four type. All the internal principals remain the same but each drain is made of three pieces (please see the previous thread)

I did not like the three piece thing and so I moved on to the two piece model five condensate drain that I use today. Here's a couple "o" three shots.










This is an upside down photo of the model five, external, condensate drain that is on my personal Frank S. I wrote about its design and operation on the previous thread.











Another fuzzy view, but please notice the through holes in the plugs in the side of the spuds. The only function they serve is to align both spuds, fore and aft, during assembly. They are pressed in with a pin gauge bridging the gap and insuring alignment.










This last photo fuzzily shows the spuds with the through plugs ever so slightly sticking out. Those plugs have a .001" annular groove around them for condensate drainage. In closing I encourage you to visit the previous thread to learn the theory behind all these "automatic" condensate drains. 

The "previous thread" mentioned lastly is this one.


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