Paddleducks
Other Marine Models => Live steam => Topic started by: GreeboTheCat on January 30, 2008, 12:59:16 AM
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Do I have to buy distilled water for the boiler or will ordinary filtered tap-water do. We live in an area of high calcium content so we always filter our water for use in the kettle and it seems to keep the kettle pretty clean. Will this filtered water be ok for my boiler.
Greebo
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Hi Greebo,
It is better if you use distilled water. Having said that I must admit that most of the time I use tap water. You can just plain water, but you may have to descale yearly.
Regards,
Gerald
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Hi PD's...Greebo...in an old OFFLINE posting, Sandy mentioned...that he preferred copper over brass for tube work & "filtered or distilled water is fine but what ever you do.....NEVER use de-ionized water"...at elevated temperatures this attempts to re-balance it's ion level & literally eats brass away..appears that the same didn't apply to copper...so this was more to do with brass tube work than copper boilers
In OZ we have a product called CLR..... clears & removes [calcium, lime, rust] from eg., your kitchen kettle - amazing product
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Greebo,
As Gerald, Derek and Sandy says, preferably distilled, but gets rather expensive.
I would use your filtered water, and keep a lookout for scaling. It is fairly easily removed.
I also used to use a stainless steel thermos flask, and take hot water with me to the lake, saves a lot of warm up time and fuel. Enough for about 3 x 40 minute runs.
I have been using tap water in my boiler for well over fifteen years, and only now just considering a flush out (somehow I have got some steam oil in there). But I do live in a fairly soft water area.
John
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Goodness PD's...bogstandard should watch what he gives his boiler to drink....steam oil ??? ??? ??? & the following is not directed at John....as I know I am not capable of teaching an old experienced DOG new tricks :P :P :P
Sandy also covered this subject a few years back & suggested a tea spoon of kitchen liquid washing detergent to a 7/8 full boiler & bring to the boil & then tip out & repeat a few times.......& each time flushing with clean near boiling water
Steam oil on the boiler internals and externals of the water tubes would change the surface tension of the boiler water to the metal and marginally lower the heat transfer back to the boiler water...but I guess the resultant change would be 0.000000001 of a % reduction varaince
Sandy did note .....that on no occasion should any petrochemical clearner be used with model boiler internals...where is that emiticon of the rocket Eddy???????????
regards
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Hi Derek,
All I can think of is that when the boiler cooled down, somehow some oil got sucked back from the lubricator. Maybe the cooling of the steam caused a drop below ambient pressure.
All I can say is that it makes a terrible mess, can't see thru the sight glass.
No matter what Sandy says, it is going to get a dose of some sort of degreasant, maybe Gunk, before I start the descaling and refurb process.
Should be good for a few more years as a test boiler for the workshop.
John
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????? Hi PD's......cannot understand John :o :o :o
a) if the pressure in the boiler = say 1 Bar, the pressure acting upon the oil in the lubricator = 1 Bar
b) if the diameter of the boiler internal is 100 mm & the diameter of the lubricator is 10 mm, we have a volume area ratio of or for [fixed] expansion at equal pressure = ZERO...so we must change the balance of volume by a change in pressure
c) to get oil from the lubricator under [pressure+turbulence] back to the boiler internals.....the boiler pressure needs to be vented to partial atmosphere.... >:( >:( >:( ...whilst the lubricator is isolated on the discharge side.......
PD's is so quiet at the moment & live steam still the ::) :P :) ;) :D best folder....so if you could comment here would be appreciated by all members
regards
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It IS VERY quiet on PDs at the moment, I was thinking the very same. Anyway, as the word "lubricator" was mentioned... oo er missus ;) as I'm about to test out my system for the first time, how much oil (steam oil of course) do I put in the lubricator. Also, as I'm a complete newbie at starting up a steam plant, is there a recognised sequence to the process?
Thanks Greebo
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>>>>>> Hi PD's &.......Greebo...providing you have purchased a QUALITY lubricator component....all of the engineering has been pre calculated
The lubricator function [amount of displaced oil] is relative to the steam pressure & volume passing through it....so that volume of steam is also subjected to the orifice in the lubricator & hence forms droplet/s of water [heavier than oil] so displaces the same volume of steam oil into the steam path toward the engine ::) ::) ::)
So just fill the lubricator to the top [good quality steam oil] prior to your first bench steam test & then monitor the spent steam discharge without getting burnt :o
The spent steam [prior to your de-oiler] [oily steam to water seperator] should be oily to the thumb & fore finger
Naturally the first few bench tests are critical in confirming the amount of steam oil consumed per boiler fill
There is literally no adjustment possible so functionality will depend on the quality of the manufacturer - you could do Goggle search on displacement lubricators for model steam & spend two days of interesting reading ;D :o 8) :P :'(
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Thanks for the info Derek. My Lubricator (and in fact most of my steam plant) was sourced from that well known Scotish purveyer of quality steam equipment, otherwise known as Sandy from ACS so I think the quality aspect goes without saying :)
Greebo
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Hi PD's......Greebo also asks " I'm a complete newbie at starting up a steam plant, is there a recognised sequence to the process?"
I am hoping that a more experienced member will respond here..but ask a few more questions firstly about your propsed tests
a) are you going to bench test with the steam drive out of the vessel or bench test the set up in vessel in the bath or pool?
ultimately the latter is the only method of determining actuals with the engine loaded & nominate say 20% engine load/speed for test 1 for one boiler fill, then say 50% engine load/speed for test 2 for one boiler fill etc etc
b) it's more a set of parameters you need to establish once you have a set of recommended sequences,,, like
c) consume one full tank of gas = what % of boiler water consumed? or visa versa?
d) how many full boilers consumed = the steam oil consumed?
e) remember it is best to complete the initial tests without your oil seperator - unscrewing the lubricator cap will only confirm oil at the same full up mark as you installed - it is the remaining oil ......& the % of water below that you need to benchmark as a function of the number of boiler fills
Seems like more ??? ??? ??? ??? ??? ??? ??? than ...so I will be interested to see a set of generic procedures prior to steaming....regards :o
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GOSH :o er...
I must admit that my testing was going to be a bit more basic than that but then I am a newbie :-[
My plan was to run it all up on the bench to mainly verify that I had steam-tight connections and that the engine DID turn under steam power etc. etc. then the plan was to take it to the pond and let 'er rip. Only kidding, I am if anything a bit over cautious when it comes to first flights or first sailings but I hadn't really put much thought to how long a boiler full of water would last. Also, once I've sorted out all the bugs and got a few afternoon's sailing under my belt, I start thinking about the next project which you'll be pleased to know is going to be a Paddler :). How about this though... my missus is so impressed with the look of the steam launch she actually said I could keep it in the house on show!
Greebo
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Hi Greebo
I've been following this thread with interest. Just a few observations
Testing: Certainly run the plant before finally mounting it in the boat. If possible have a small test tank with a shaft and prop fitted, and run the lot under load. Definitely see how long the fuel and/or water last. At least with an open launch you should be able to see how the water level in doing.
Water: I've been running my launch for over 20 years now, most of that time with automatic water level control, and have always pumped straight from the pond. The boiler has never been de-scaled. The water at St.Albans is pretty foul considering the number of ducks and geese around. It still steams well, so I don't think I have any problem with scaling up.
Lubrication: Let me say straight away that I don't like lubricators where the steam passes straight through, I always mount mine to tee into the steam pipe. On one of my early plants, I was using quite a lot of super heat, and the straight through lubricator got so hot that no steam condensed after the first few seconds. I also like to have a needle valve in the lubricator so I can control how much oil is fed in. All a bit of trial and error, but with a bit of experience it is easy to use.
The picture shows the plant in my launch, and hopefully you can see the lubricator (the chipped black thing) and needle valve.
Malcolm
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Derek,
Sorry to keep you waiting so long. The only way I could see oil being sucked back is by having the throttle closed, so that the boiler and all lines were below ambient when it cooled down, and when I moved the throttle it sucked air and any contents in the lines straight back to the boiler. That is the only explanation I can give, as I was scrupulous in what went into the boiler filler hole.
Everyone else.
This is what I knocked out a couple of weeks ago for some lads that have 'toy' engines as they call them. The first two pics show offset (the type Malcolm prefers) and inline lubers. For horizontal or vertical steam lines. No adjustment on these, but the lads love 'em, they can steam their little engines for about an hour before they need to be topped up. The tall one was a special for 3/16" pipework, for a chap in Canada.
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/lubebuild4.jpg)
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/allthree.jpg)
These pics show the matching oil catcher for the lubers. These are a necessity if sailing, as the local councils don't like oil being dumped in their already polluted and duck crap ridden lakes. This one was made from large bore plumbing pipe and a few bits of brass and copper.
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/trap3.jpg)
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/trap4.jpg)
John
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Hi PD's ...& :P...is it an optical illusion Bogstandard....that in your "oil catcher"....
a) The inlet with the dog-leg is 1/8" OD & the straight discharge is 5/32" OD copper tubing?
b) You may need to explain how this works???? as I could only visualise the oily discharge steam entering the deoiler & spraying onto the inner walls or a baffle & the oil component being released from suspension & the clean steam carrying on :-\ :-\
c) In the ACS website....an American modeler has an ACS deoiler which can be isolated & as such is a pressure vessel - Sandy confirmed dished ends & a such was of a higher rating....however I see your CREWE Eng variant has a removable brass lid/cap......I hope this is a solid brass cap [100gms?]
BTW...the polished copper & brass in one component certainly looks the part 8) 8) 8) ::)
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Derek,
Just to answer your last comment first, it is a nice contrast if you don't want to paint something, brass and ali also has the same sort of contrast effect. The was a quickie knockup hence all the scratches and such, just to explain a principle.
With ref to your other queries, the exhaust is larger than the inlet. This is attempting to make the steam expand in the chamber, so dropping the low exhaust pressure even further, forcing the steam into releasing condensation, at the same time the 'bent' pipe is directing the steam downwards and onto the cooling outside face of the chamber and swirling the steam about, again forcing it to drop more water, laden with oil.
If you are getting high pressures at the exhaust, to me, either the engine is grossly inefficient or your are running with too much pressure in the first place.
The cap is a fairly tight fit, but not all that heavy.
I have been making them this way for many years and never had a cap lift off. In fact I have made them with loose caps with the same operating results. They just rattle about a bit, usually due to vibration from the engine.
Here is mine next to a very expensive commercial unit that I bought about 20 years ago, and is an absolute crap design, because you can't easily empty it at the end of a run.
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/trap5.jpg)
John
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Hi PD's & thanks Bogstandard for the :-X comments .........I too found the standard "de-oiler"...offered as common between all suppliers....but lacking somewhat as you describe
A quick e-mail to ACS confirmed the option screwed port with screwed plug etc...so as to remove/evacuate the left over oil
PS......we are still waiting for another EXPERIENCED model steamer....for a listing or protocol prior to >>>>>>> steaming or bench testing??? ??? ???
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John
Looking at that commercial oil trap, I wonder what it's like inside. I assume that the inlet is the pipe almost tangenrial to the side, one of the others should be the steam outlet right at the top of the container, and the other should go to the bottom so the contents could be sucked or blown out. I have made a few like that and have had no trouble. The picture shows (amongst other things) the oil trap on the plant I built for a 24 hour endurance run. Thats the red container. Steam enters at the top and blows down onto the top of a 90 degree cone that finishes a short way from the bottom of the trap. The idea being that as the steam expands and slows down, the oil is deposited onto the surface of the cone and collects in the bottom of the container. At the left hand side there are two exits, you can see the top one, but the bottom one is hidden by the by-pass valve. Each exit has a valve which is operated by the vertical shaft seen passing through the top one. This switches the exhaust between the top and bottom.
The container should really be lagged as we don't want it to fill with condensate - only the oil. On start up, the bottom valve is open so that condensate from the whole system heating up are expelled. Once steam is coming out, the valves are switched and exhaust goes into the flue and up the funnel. At the end of the run, the valves are switched again to expel any oil etc. This has worked very well even on extended runs of an hour or so.
Oh, and the top of the container can be unscrewed if I want to give it a good clean out.
Malcolm
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Malcom,
I know the ins and outs of the commercial ones and why you designed yours as you did.
Mine is designed so that a rank amateur can knock one up with basically what is at hand, and get a working oil trap.
For the sort of people mine is aimed at, it is perfect, and they don't mind emptying it every hour when it fills up with condensate.
I am a firm believer in keeping things very simple. Less to go wrong, and usually easier to operate.
I have had people yanking out their complicated engines and popping in one of my oscillators, purely because they were fed up with fiddling rather than sailing.
John
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OK PD's.... 8) 8) we have certainly progressed a little from the humble filling of the boiler with water 8) :-X :-\ :-* :'( :'(
...............but still await the "song & verse of the steam set-up" by an experinced PD member :-\ :-* :'( :) ;) :D ;D >:( :( 8) ??? ??? ??? ???
HOW much MOORE caan,,,,,,,,,it be ?...or should I ask Bandit & Vinnie...to respond?
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Derek,
There is no such thing as a 'song and verse' for setting up a steam plant, only general notes, as each installation is usually custom fitted with doodahs and dongles that the owner deems is necessary to fit to his/her engine.
I do have one thing that I do class as important. That is the fitting of two steam control on/off valves in the line to the engine.
The first one is fitted to the top of the boiler, to allow the raising of steam to be carried out without feeding condensate laden steam to the engine while pressure builds up. Then the engine feed pipe is heavily lagged until it reaches the second control valve, that is usually fitted just before the luber.
This second valve is adjusted until the engine is running at its most efficient, then tightened in that position. There is nothing worse than seeing steam coming from all the joints on an engine because it is being over pressurized. Just enough, and no more is the order of the day. You will also find that the run times also extend dramatically when you are not wasting steam. To service the luber it is just a matter of turning off the valve on top of the boiler.
Another thing to be wary of is steam being fed up the funnel. Two reasons, one for safety and the other to protect your investment.
Even if you are feeding steam from a separator, be careful of the run lines to the funnel. Keep them as shallow an angle as possible. Condensate will gather in tight bends and be fired out of the pipework when pressure overcomes the weight. A face full of hot condensate tends to spoil your day. A spit trap on top of the pipe would be a good idea.
The other reason is to protect your investment. If firing up the chimney, get the pipe as near the top of the funnel as possible, or even up the outside. I found out the hard way, condensate formed onto the chimney inside wall and ran down onto the top of my vertical boiler, then found its way down the firetubes and dripped onto my ceramic gas burner, effectively ruining it and also setting up corrosion that removed the heatproof paint around the burner area.
These are just a few of my views, other people might have different suggestions.
John, Bandit the dog & Vinnie the mog.
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Here's an oil trap I just built because I couldn't find a suitable horizontal one. I got an old brass oil can on ebay (if you search for "eagle brass oil can 66" you might get the idea) of which I cut out the cylindrical middle section. Then I hand-hammered two bottoms out of brass sheet and soldered them to the tubular section.
The steam enters through the nozzle on the top. The exhaust pipe starts at the opposite (rear) end of the tank and runs long the apex of the tank, before it leaves the tank on the front end. Thus, the steam has to travel through the entire tank and make a 180 deg turn before entering the exhaust pipe, giving it the chance to dispose of oil and water drops.
The hex screw cap on top comes from the local hardware store (plumbing supply) and is large enough to drain the whole thing by means of a large syringe.
Regards, Moritz
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Hi PD's...Moritz...please.... you should tell PD's more as you build....like
the engine?
the boiler?
the accessories?
The new ..your de...oiler?....many years ago we could purchase "Welsh Plugs" both in steel & brass for motor engines....not sure if the brass variant is still availble
From the current engine .jpg....are you intending for the engine to be a model on the base plate?
Many PD's would await your steam comments....... :beer regards
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Hi Derek,
Hi PD's...Mortiz...please.... you should tell PD's more as you build....like
the engine?
the boiler?
the accessories?
Sooner or later, I will present this project in a seperate thread, therefore just a few comments:
The engine is a Graham TVR1A (real fun to assemble!), the boiler is the double flue Regner boiler. It may be bit oversized for the engine, but I hope to get some operation time reserves at low power, and some speed reserves on the other hand.
From the current engine .jpg....are you intending for the engine to be a model on the base plate?
No. It is meant to propel a 1:10 scale spar torpedo launch (hull still to be built...).
The wooden base plate is just a temporary rig to do the packaging of the components and the tubing job.
Regards, Moritz
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Hi PD's..... :thinking...you & ENGINEMAN could have Thornycraft PT boat races - regards