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[1967Brutus]

Canopus

Beautiful!

[derekwarner]

I am sure there are quite a few Moddlers watching on with great interest Bert    ....


In particular, I await your discussions on the separating of engine condensate [removal of the oil] & reuse of the clean water......and further the preheating of the feed water


Do you not find the groaning of the Regner feed pump  a little off-putting?


[I haven't quite figured out the Female voice in your Videos offering achievement/comments at certain points  ...is She the voice element as part of the programmed Tx?]


Derek

[1967Brutus]

I am sure there are quite a few Moddlers watching on with great interest Bert    ....

To that I can only say: My crystall ball is back to the manufacturer for its yearly overhaul and tune-up, so currently, I cannot guess what you guys want to know.
But I will answer any and all questions.

Also: None of what I write should be considered as the one and only truth, please comment whenever I post something silly or incorrect.

In particular, I await your discussions on the separating of engine condensate [removal of the oil] & reuse of the clean water......and further the preheating of the feed water

Like this one, for example, An aimed question, I can comment on.

From what I have seen, and with the oil I use (I do not have a brandname, I picked it up from a local historical steampowered tugboat, it is what real life triple expansion machines use) the dirt virtually completely concentrates in the first condensate/crud after the engine. The stuff I collect from the oil separator is mainly water with a minute bit of oil on top (order of magnitude of 98~99% water, 1~2% oil) but that oil is strongly emulsified and does not separate whatever I do (I have tried, I have stored that collected crud for 3 months and saw zero separation) The amount of that crud varies with outside temperature, I think it is the steam that condenses IN the engine, and gets mechanically mixed with the oil. In summer season, about 60 ml per hour, currently closer to 75. So we're talking about a loss of non-recyclable water of roughly 10% of the total boiler feed. A bit less in summer, a bit more in winter.
The only thing that can be done with this crud, is to discard it.
The oil separator collects that and whatever steam leaves the oil separator, is basically clean. I do not even dare put a number on it, but it is closer to ppm range than to percentage or even promille range.
So we have a potential reclaim of 90%, give or take. This steam is routed through a condenser/preheater, where part of the steam condenses, the remainder is vented to atmosphere.

This condensate is led through a small filter compartment containing about 60 cm2 (6 strips 5 x 2 cm, stacked vertically like bookson a bookshelf) of oil absorbing cloth, as is used cleaning up marine oil spills and such. This is really weird material, it does not absorb water, it floats on water, and shows a very strong affinity to oil. It is commercially availlable for about €0,75 per sheet of 50 x 40 cm (but unfortunately only in boxes of 100 sheets minimum), and one sheet would typically last me for at least 40 hours of steaming or so. Initially I had to replace everything every hour, but that was before I fitted the oil separator with an auto-drain. After that, it really is no problem AT ALL... The water is clean and stays clean and the filterstrips show a very mild smear of discoloration after 10 hours or so.
The compartment is about 25 cm3 in volume and has a syphon: Water enters the filter compartment, passes the filterstrips, then has to pass UNDER a divider bulkhead that retains any floating oil not yet bsorbed by the filter. From under the divider the now clean water flows upwards and via a spillway into the feedwater tank.
Just for safety (the engine could theoretically fling oil droplets around) a sheet of that oil absorbing cloth covers the entire surface of the feedwatertank, but so far I have not yet seen the need to replace that.

And that's it, basically. Make sure the oil separator works properly by ensuring no liquid build up, and the condensate will be reusable with even the slightest bit of filtering. Not critical at all. No fussing with the passing time of the water in that filter compartiment (which in my case currently is approx 5 minutes by the way), because the condensate from the condenser is basically clean to begin with.

The preheating of the feedwater, there is not too much to tell about that. In reply #9 I showed how I built the condenser: It's a coil made out of 1 metre copper tube (3 mm OD) wound around a core of about 2 cm diameter (core removed after winding, of course, duh...). That coil is placed into a tube of about 3 cm diameter and about 10 cm length, and capped off with Aluminium discs. The feedwater is passed through the coil, the clean exhaust steam is passed through the condenserbody, the steam surrounds the coil and heats it. Condensate is drained off, remaining steam is vented to atmosphere. That basically is all there is to it. No controls, no automation, it just is what it is. The feedwater temperature is very constant. I do not know the exact temperature because the probe is tied to the outside of the feedwater line and then wound in cotton cord for isolation. Reading is around 71 degrees plus or minus 1 and steady regardless of load. Experience with these probes and isolation (I used the same method of measuring for pressure control, that's how I know) suggests that the actual feedwater temperature is around 85~90 degrees, but I have no way of knowing that for sure... But it basically HAS to be, because you cannot reach much higher temperatures using atmospheric steam, and although the inlet temperature at the heater coil rises by about 15 degrees throughout the run (feedwater tank warms up due to the inflow of hot condensate) the outlet of the heater remains constant, meaning it reaches end temperature achievable with atmospheric steam.

With only a feedwater preheater, the reclamation is practically limited to about 35~40% of total boiler feed, approximately. More would require additional measures. There are two or three possibilities to increase that to "everything there is to reclaim" but these options each have their own set of issues. I have only considered them in the form of a thought experiment ("mental simulation") only, and based on that rejected them all.

The easiest way is to install a pipe of suitable diameter underneath the boat, a bit like a bilge cooler. Upside is unlimited cooling capacity, downside is that it requires the feedwater preheater to be sealed up because it becomes "pressurized", and it requires this pressure to push the collected condensate back up into the boat. This backpressure can be unpredictable and affect the engine's performance.
It requires two hull penetrations, and at least one of them is subject to high temperatures, which also can cause issues endangering watertightness of the boat.

The most technically neat solution is to enlarge the condenser and install a 2nd coil through which outboard water is pumped. This requires a pumped volume of at least 6 times the boiler feed. Requires a pump (power) and a weedfilter. In my case, the required dimensions simply would become unmanageable.

The technically simplest way is to fit cooling fins on the condenser shell to increase heat dissipation to outside, but this requires eigher ventilation or an open boat, and in case of the latter, is downright ugly to look at.

All of them would allow for a MUCH smaller feedwater tank, which would mitigate the increase in dimensions of the condenser a bit.
For example, I run a feedwater supply of 375 ml right now which allows me to run 50~55 minutes. Maximizing water recycling would allow for a feedwater tank of only 100 ml for the same duration.

Do you not find the groaning of the Regner feed pump    a little off-putting?

Absolutely! But... the really weird thing is, that noise really is loud and annoying on the testbench or in the bathtub.... but as soon as the boat is 2 metres away from the dock, it is literally inaudible. I don't know how that works, but the first weeks I had that pump in the boat, I continuously brought the boat in to check if it was still running, I had to literally visually check, because I could not tell. And mind you, I actually DO have that "engineers ear", picking up the subtlests of sounds that shouldn't be there, and immediately noticing if a subtle sound that should be there is missing.

If you don't believe, check my vids if you can hear the pump running, for example this one:
https://www.youtube.com/watch?v=jqthLIf8VR4
The camera's mic is sensitive enough to pick up traffick 200 metres away through a forrested area, it picks up birds whistling at 50 metres, but around 1:40 the boat is less than a metre away and that's where you can hear the pump VERY faintly...
I have no clue how that works acoustically, but it is a fact, that in practical use the pump is inaudible.

[I haven't quite figured out the Female voice in your Videos offering achievement/comments at certain points    ...is She the voice element as part of the programmed Tx?]Derek

Yup... That thing can basically do anything I want it to do, including calling out telemetry values, but for testing purposes, I told it to give warnings for "cruise", "normal" and "landing" throttle valve settings so it would be easier to do repeatable tests: It is very hard to determine an improvement in operating time if you are not running the same speed between tests.
That lady indeed is annoying, I have since replaced those comments with beeps as they have served their purpose (basically, done testing), not nearly as annoying when actually on the pond.

What is left, is a warning to come in when the boiler pressure drops below 1 bar when the burner is at full. That tells me that either the fire has extinguished, OR the fuel is near finished. I'llprobably also will program an alarm for low and high feedwater temperature, as those are symptoms of failing pump or leaky valves respectively.

[Geoff]

As you may be aware on real ships of the 1890's to 1906 they typically used triple expansion engines and I they would also look to condense exhaust steam and re-use the water. I read somewhere they have settlement tanks, literally an open topped bath. Because oil floats on the surface they would physically scrape it off and then re-use the clean water. One of the benefits of using turbines was that the oil and water did not mix (okay there was a little bit because of bearings etc) but the condensate was much cleaner and therefore easier to re-use.


In real ships the condensers actually condensed the exhaust steam so fast they caused a partial vacuum so there was a further pressure differential between the steam pressure and the atmosphere which gave them an improvement in fuel efficiency in the region of 5% to 10%. Ships can actually sail a little faster in cold water because their engines will develop a little more power because the condensers work better. In model terms the effect is negligible and we do it to avoid contamination of the lake and get clean steam to come out of the funnels.



I have seen lots of people preheat their boiler feed water but in general do not think it makes a lot of difference at our scale because it takes relatively little energy to heat water to 100 C  particularly given the small drops we are pumping into the boiler but something like 4 times the energy to change it into steam because its changing state - liquid to gas. Still its quite fascinating to see this and that's all part of the fun of the hobby, we do it for fun as much as actually sailing.


On Canopus and my other  ship Velox I site the oil separator/condenser next to the gas tank so they are actually just touching. The waste heat then acts to gently warm the gas tank which is a good hand warm at the end of a run irrespective of the weather. This keeps the gas pressure from dropping. Similar to the above the gas is changing from liquid to a gas and needs energy to do this so its sucks the heat out of the gas tank and the surrounding air which is why the gas tank can feel cold.


Cheers


Geoff

[1967Brutus]

As you may be aware on real ships of the 1890's to 1906 they typically used triple expansion engines and I they would also look to condense exhaust steam and re-use the water. I read somewhere they have settlement tanks, literally an open topped bath. Because oil floats on the surface they would physically scrape it off and then re-use the clean water. One of the benefits of using turbines was that the oil and water did not mix (okay there was a little bit because of bearings etc) but the condensate was much cleaner and therefore easier to re-use.


In real ships the condensers actually condensed the exhaust steam so fast they caused a partial vacuum so there was a further pressure differential between the steam pressure and the atmosphere which gave them an improvement in fuel efficiency in the region of 5% to 10%. Ships can actually sail a little faster in cold water because their engines will develop a little more power because the condensers work better. In model terms the effect is negligible and we do it to avoid contamination of the lake and get clean steam to come out of the funnels.

I have worked with steam for about 15 years, and although never with piston engines, I have actually worked with steam turbines.

Just a few corrections: Those oil separator systems usually are what they call cascade tanks, a tank divided in compartments by a series of over and under bulkheads: Water passes under one bulkheas, over the next, under the one after that, etc etc.
They are rarely open top, not even in the old days, for reason of oxygen pick up and accidental pollution risks (a burst oil pipe somewhere in the engine room, would cause severe problems).
In factories and poweplants and such, they were more commonly open topped.
In each compartment the floating oil is absorbed by either Loofah Sponges or the same oil absorbent cloth I use. These sponges or cloths take some attention, and proper adjustment of the oil dosage plays a HUGE role in efficient operation here. In heating plants or turbine plants, usually a single cascade is enough, but for reciprocating, usually the cascade is 5 or more compartments.

The vacuum in condensers is actually NOT created by the rapid condensation of steam, but by the removal of "non condensables" (air). In reciprocating engine installations this was done by an engine driven "wet air pump", in turbine installations the vacuum was created by a cascade of 3 or 4 steam driven eductors.
Normally, in order to be able to start up a turbine steam installation, the vacuum has to be created first, but of course this is not possible in reciprocating installations, because no running engine=no operating wet air pump.

I have never seen bearing oil in the return from turbines, since usually the bearings are outside of the steamcircuit and contact between bearings and steam is impossible.

I have seen lots of people preheat their boiler feed water but in general do not think it makes a lot of difference at our scale because it takes relatively little energy to heat water to 100 C  particularly given the small drops we are pumping into the boiler but something like 4 times the energy to change it into steam because its changing state - liquid to gas. Still its quite fascinating to see this and that's all part of the fun of the hobby, we do it for fun as much as actually sailing.

People don't pay attention then... It actually DOES make quite a bit of difference. There is about 1~1,5 minute in time, from the moment I open the main steam valve and get the engine moving, until the preheater starts to function. By that time I usually have the burner on auto, and steam throttle at 50%.
The moment hot water starts entering the boiler instead of cold, is very clearly visible in the burner reducing fire. It also is very clearly noticable in the burners ability to maintain pressure in high demand situations for longer with less fire.
But that is not the only issue: whichever way you turn it, the cold feedwater is NOT heated by the burner. It is heated by the surrounding water. This means that in a part of the boiler, the water stops boiling because of the cold inflow. Since the steam has to be generated somehow anyhow, this means the boiling process in the other parts of the boiler has to become more violent, and THIS is fairly visible in the behaviour of the level glass.
Ideally you want an as "quiet" as possible water surface, because that reduces water carryover and improves efficiency.
The difference I have observed in fuel consumption due to preheating, are in the order of magnitude of 15%. I really don't care about the fuel savings (I have to blow off unused gas before refilling anyway for other reasons, and the gas in not all that expensive to begin with) but the steadier operation, less violent boiling, reduced water carryover and thus more consistent cylinder lubrication all work towards a longer engine life, more consistent operation, and it does not cost me anything except for the one time investment in making a proper preheater (which cost me less than €20,- and about 1,5 hour to build).

I fully admit, that the differences, especially if looking at each item individually, are not all that big. Then again, they basically come for free or at worst a one time investment rather than a continuous effort, and all combined, they DO make a significant difference.
I went from max 15 minutes operating time on a sedate pace, a water consumption of close to 900 ml per hour, a gas consumption of about 65 grammes per hour, cylinder oil consumption of about 4 ml/hr, machine oil consumption of anywhere between 5 and 10 ml hr, and "ages" of cleaning between runs,
to 50 minutes of operating time at a lively pace, approx 350 ml of water per hour, 55 grammes of gas per hour, less than 1 ml of cylinder oil per hour, less than 1 ml of machine oil per hour, and the clean-up after use is reduced to about 5~10 minutes.

Say what you will, but to me those are very real differences: I know myself, and this boat would rather quickly have become a shelf queen without the mods, simply because one hour cleaning after 2 or 3 15-minute runs is not my thing,
And as you said yourself, if you don't use it you'll lose it...

On Canopus and my other  ship Velox I site the oil separator/condenser next to the gas tank so they are actually just touching. The waste heat then acts to gently warm the gas tank which is a good hand warm at the end of a run irrespective of the weather. This keeps the gas pressure from dropping. Similar to the above the gas is changing from liquid to a gas and needs energy to do this so its sucks the heat out of the gas tank and the surrounding air which is why the gas tank can feel cold.CheersGeoff

This is the only thing I have been breaking my head over so far: There is PLENTY of waste heat in the boat, but I can't yet figure out how to transport that heat to the gas tank without creating an undesirable side-effect. I have been thinking about using "heat pipes" but that will get very ugly.
Rerouting the exhaust steam line will create issues with unfavourable condensate and backpressure.
Right now, I am thinking that probably the easiest will be to Epoxy a 5W resistor to the tank, and heat the tank electrically (5W is approximately the heat needed to evaporate gas at the rate of consumption). Not sure if or how I will solve that, but at least it will give me the possibility to somehow "control" that heating via telemetry. I still have one unused temperature channel that I can use to switch that heating based on the fuel line temperature.
But I don't particularly like that "solution" when there is literally around 200W of unused waste heat availlable.

Oh well, you can't win them all...

[1967Brutus]

Remember that urge for "consistency"?


I found an old HobbyKing combo of regulator, switch and voltage display all in one, and decided to install a 2S 2200 mAh LiPo. That way I have a constant voltage for the feedpump.
with the NiMH there is a voltage drop of about 15% during discharge, meaning the feedpump will run slower at the end of a battery charge.

And since that LiPo contains 16 Wh as opposed to the NiMH only 9,5, suddenly there is a bit of capacity to spare to add electric heating to the fuel tank.
5W should do it.


So here's the battery
https://www.modelbouwforum.nl/attachments/20231019_230739-1-jpg.557388/
Here's the switch
https://www.modelbouwforum.nl/attachments/20231019_230804-1-jpg.557389/
and I integrated a temperature sensor (for start/stop of the fuel cell heating) in the cradle of the fuel tank
https://www.modelbouwforum.nl/attachments/20231019_230659-1-jpg.557390/
The switch for that, the sensors, connectors etc, I still had lying around, all I need is one or two resistors that I can epoxy to the fuel cell.

[derekwarner]

Thanks Bert....I read & reread post # 28 a few times with great interest

[I am familiar with ‘Oil-Sorb’ sheeting [we installed it {40 years ago} under the internal ship mounted travelling cranes of the BHP Iron Duke & Iron Monarch to eliminate drops of hydraulic oil landing on the 20 tonne HRC’s loaded for between Kembla & Westernport] - This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering 

I ‘inbuilt an issue’ when installing a Microcosm P3 piston water pump,  with eccentric driven vertical down piston shaft, from my Saito Y2DR horizontal steam engine  …….the result was a migration of lubrication oil down the shaft and pooled around the shaft & into the waterside of the system, despite the integrity of the pumps piston seal

So my issue was oil in the water pressure side, and so without any form of pressure filter …….

Derek

 
 

[1967Brutus]

Thanks Bert....I read & reread post # 28 a few times with great interest

[I am familiar with ‘Oil-Sorb’ sheeting [we installed it {40 years ago} under the internal ship mounted travelling cranes of the BHP Iron Duke & Iron Monarch to eliminate drops of hydraulic oil landing on the 20 tonne HRC’s loaded for between Kembla & Westernport] - This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering 

I have no idea if "Oil Sorb" is the same stuff that I use. I don't think that 0,75 Euro per season (give or take) is cost prohibitive, but having to buy a box of 100 sheets, yeah, I can imagine that that is not the most ideal way.
But there are easier ways to aquire, like asking around in local car workshops, communal accident response teams, fire brigades, that kind of thing, to see if you can get a few sheets.

Worldwide shipping is a bit tricky, but locally I would have very little issues purchasing a box of 100 sheets and distributing it among fellow model steamers at costprice. Maybe local clubs can do something like that? Many RC plane clubs purchase their glowfuel in a similar way.

I ‘inbuilt an issue’ when installing a Microcosm P3 piston water pump,  with eccentric driven vertical down piston shaft, from my Saito Y2DR horizontal steam engine  …….the result was a migration of lubrication oil down the shaft and pooled around the shaft & into the waterside of the system, despite the integrity of the pumps piston sealSo my issue was oil in the water pressure side, and so without any form of pressure filter …….Derek

oh, dang, that's a nasty one, but at least be happy your steamplant is a law-abiding steamplant, it conforms to the law of unintended consequences.
There's not much you can do about that specific issue, other than relocating the pump to an oil free spot: Viscosity of oil combined with the wetting properties of oil towards metal will absolutely drag oil against the working pressure into the waterside. Nothing can be done about that.
But in all honesty and fairness, I would have overlooked that issue too... Totally! It is one of those things you don't initially think about and in hindsight slap yourself for not having caught it before executing...

What you can do is feed the water through some sort of inverted "displacement oiler" of sorts, where water velocity is very low, allowing the oil to rise to the top and remain in the separator. Maybe that will have some effect. That oil is not emulsified, so it most likely will settle out fairly well. The separator should have about the volume corresponding to 5 times the flowrate per minute, allowing for a settling time of 5 minutes.

Only other option is relocating the pump, but I guess that's not really an option?

[1967Brutus]

Remember that urge for "consistency"?


I found an old HobbyKing combo of regulator, switch and voltage display all in one, and decided to install a 2S 2200 mAh LiPo. That way I have a constant voltage for the feedpump.
with the NiMH there is a voltage drop of about 15% during discharge, meaning the feedpump will run slower at the end of a battery charge.

And since that LiPo contains 16 Wh as opposed to the NiMH only 9,5, suddenly there is a bit of capacity to spare to add electric heating to the fuel tank.
5W should do it.


So here's the battery
https://www.modelbouwforum.nl/attachments/20231019_230739-1-jpg.557388/
Here's the switch
https://www.modelbouwforum.nl/attachments/20231019_230804-1-jpg.557389/
and I integrated a temperature sensor (for start/stop of the fuel cell heating) in the cradle of the fuel tank
https://www.modelbouwforum.nl/attachments/20231019_230659-1-jpg.557390/
The switch for that, the sensors, connectors etc, I still had lying around, all I need is one or two resistors that I can epoxy to the fuel cell.

Meanwhile the switch and telemetry-function to activate that switch have been insalled/progged, waiting is for a few "cement resistors" to heat the gastank.

Curious what it will bring...

[1967Brutus]

This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering 

I looked into this, and although Oil-Sorb appears to be a brand name, as far as I can see it is the same stuff I use.
Unless local regulations or taxes or whatever have an influence on price, it really should be relatively affordable (at the rate I am using it, less than 1 Euro's worth per month, and I am running an extreme amount of hours per month).
Make sure you use the white version, NOT the grey version. The white version absorbs only oil, the grey version absorbs oil and water, meaning it has reduced effect when becoming waterlogged.

[derekwarner]

Well, would not break the Bank, but better if another 99 Modelers would need a sheet .....yes the white version [adsorbs petrochemicals 'oil' only]


https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjSsZz1rIWCAxU12kwCHcpmCfkYABAMGgJ0bQ&gclid=CjwKCAjwysipBhBXEiwApJOcuw9DjsMMuYbSGtFvyJxc9NmSsE-viN-RTQYk7kpZGwKulVzQyk9PKBoCGhYQAvD_BwE&ohost=www.google.com&cid=CAESV-D2xMtXYLFtldxxPT5qrXx4sOIuNZGGkDYQw6WjJeS7Vjt2Yk-cTM7wplq8isPxTQLXg5mGIOjyRdKUVqab3P43fCjF_AB21tq8CxXUP-_mHV9_TjtMog&sig=AOD64_2ofYquLe6EHRuXd7CGnXPNG7hpZQ&ctype=5&q=&ved=2ahUKEwi02pb1rIWCAxULhVYBHQ_xAW0Q9aACKAB6BAgDEFM&adurl=

[1967Brutus]

Well, would not break the Bank, but better if another 99 Modelers would need a sheet .....yes the white version [adsorbs petrochemicals 'oil' only]


https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjSsZz1rIWCAxU12kwCHcpmCfkYABAMGgJ0bQ&gclid=CjwKCAjwysipBhBXEiwApJOcuw9DjsMMuYbSGtFvyJxc9NmSsE-viN-RTQYk7kpZGwKulVzQyk9PKBoCGhYQAvD_BwE&ohost=www.google.com&cid=CAESV-D2xMtXYLFtldxxPT5qrXx4sOIuNZGGkDYQw6WjJeS7Vjt2Yk-cTM7wplq8isPxTQLXg5mGIOjyRdKUVqab3P43fCjF_AB21tq8CxXUP-_mHV9_TjtMog&sig=AOD64_2ofYquLe6EHRuXd7CGnXPNG7hpZQ&ctype=5&q=&ved=2ahUKEwi02pb1rIWCAxULhVYBHQ_xAW0Q9aACKAB6BAgDEFM&adurl=

Trust me: Once you get to where I currently am, you'll want to have 5 sheets in stock for just in case, so if you can find 19 other likeminded steamers (or bike/car restorers, or whatever), you're in business...
That link is exactly the stuff I  have and the price is virtually identical.

Forgot to tell: I brought 5 sheets home from work...

[ooyah/2]

Hi Bert,
Many thanks for the very informative observations on running a steam plant, but may I comment on the fact that we are a dying breed of enthusiasts in model steam boats.
In my club in Glasgow about 15 years ago we had 10 members devoted to steam propulsion, most of us being retired engineers who helped out those with no experience at all and as we were all working to a financial budget no electronic devices were use nor available and doing so our steam members learned how to control the model by experience   and by bringing the model into the edge to check boiler levels  and a drop of oil.
Unfortunately all of the members except for myself are left and no younger members have been interested in steam power.


Consequently all of our fittings were home made including boilers and engines from castings, so here ids a sketch of a boiler feed feed water heater and oil separator made from scrap copper tubes that were supplied just for the asking at a local plumber free of charge and it now installed in a steam plant.   


To empty the condensate all that is required is to close the exhaust steam to the Funnel ( squeeze ) and open the drain valve at the bottom using silicone tube that the flyers use to empty the tank simple but effective.


Once again thanks for your explanation on using electronics.


George.

PS apologies for pics out of sequence.


 

[1967Brutus]

Hi Bert,
Many thanks for the very informative observations on running a steam plant, but may I comment on the fact that we are a dying breed of enthusiasts in model steam boats.
In my club in Glasgow about 15 years ago we had 10 members devoted to steam propulsion, most of us being retired engineers who helped out those with no experience at all and as we were all working to a financial budget no electronic devices were used and doing so our steam members learned how to control the model by experience   and by bringing the model into the edge to check boiler levels  and a drop of oil.
Unfortunately all of the members except for myself are left and no younger members have been interested in steam power.


Consequently all of our fittings were home made including boilers and engines from castings, so here ids a sketch of a boiler feed feed water heater and oil separator made from scrap copper tubes that were supplied just for the asking at a local plumber free of charge and it now installed in a steam plant.   


To empty the condensate all that is required is to close the exhaust steam to the Funnel ( squeeze ) and open the drain valve at the bottom using silicone tube that the flyers use to empty the tank simple but effective.


Once again thanks for your explanation on using electronics.


George.

PS apologies for pics out of sequence.


 

Hi George,


That type of oil separator (minus the feedwater preheater coil) is still being sold by Regner if I'm not mistaken. It is a simple principle, and in a sense it is identical to what I use. Difference is that in my case, the pressure to discharge the slops is generated by nothing else than the diameter of the steam exhaust pipe, and the discharge is continuous, to a separate receptacle.

I need that continuous discharge, otherwise the separator gets filled up approximately halfway the operating duration, and once that happens, oil will escape with the exhaust steam that feeds the preheater/condenser, end up in the reclaimed condensate in emulsified (non-separable) form, and subsequently pollute the boiler.
I divided the functions of oil separation and feedwater preheating over two separate units, in order to obtain clean condensate that can be reclaimed to the feedwater tank.

Steam indeed is a bit of a dying breed, just as wet fuel (more specific, glow fuel) is in the RC aeroplane world. But there's nothing wrong with attempts to revive interest a bit.
Over the past 7 or 8 years I have therefore focused on modifying the small engines designed for glowfuel (expensive and messy, increasingly difficult to purchase) to where they can run on regular petrol and 2-stroke oil, cheap, frugal, easy to buy and lots cleaner.
I have come as far as (for example) a 5 cc fourstroke with electronic ignition and sparkplug, but ALSO electronic mixture control, burning less than 180 ml of fuel per hour, practical, reliably running clean throughout the entire rev range, and extremely userfriendly.
A few people (about 100 worldwide) have followed, and maybe, MAYBE the industry picks up on it. There are a few indications that they do, actually.

That's a bit where I'm coming from.


I do not have the illusion that I can, on my own, generate interest in steam for a new generation, but what I most definitely CAN do, is show folks that it is OK to deviate from the trodden path onto roads less travelled.
There is so much fun to be had, so much to experiment with and so much to learn...

One of the things I noticed in the field of aeroplanes, is that people DO still have an interest in wet fuel, but are turned off by the fuss and the mess. Whenever I demonstrated my engines, there was a definite interest in the long flight times, the ease of operation, reliability and relative cleanliness.
I think that also is the thing that turns people away from steam: the maintenance, the need for control and checks (regularly coming to the edge to check boiler level, oil, etc) and I focused on setting up mine to run basically unattended for as long as I could stretch the operation time.

I like a beautifully built boat just as much as anybody else, but for me, I derive the most pleasure from the knowledge that my steamplant is "optimised" and basically performs like very few out there... And wouldn't it be nice if after posting here, other people will build plants that perform even better than mine?

Wo knows... one day...

[1967Brutus]

Meanwhile the switch and telemetry-function to activate that switch have been insalled/progged, waiting is for a few "cement resistors" to heat the gastank.

Curious what it will bring...

Well... resistors have arrived, and installing them took all of about 10~15 minutes:
https://www.modelbouwforum.nl/attachments/20231021_153633-1-jpg.557527/

I still need to finetune the setpoint, protect the temperature sensor a bit better against external influences, but it works fine.
As long as I set up the control such, that the gas tank maintains about 13 degrees Celsius, gas pressure remains high enough for the burner to have some headroom maintaining steam pressure at full ahead until the last drop of gas.
Works excellent, heating switches on and off on demand, the load on the LiPo is not at all noticable in the onboard voltage, and I think there is about 2,5 hours of safe steaming in the batterypack.


I'm happy...

[ooyah/2]

Hi Bert
I do not have the illusion that I can, on my own, generate interest in steam for a new generation, but what I most definitely CAN do, is show folks that it is OK to deviate from the trodden path onto roads less travelled.
There is so much fun to be had, so much to experiment with and so much to learn... .
 performs like very few out there... And wouldn't it be nice if after posting here, other people will build plants that perform even better than mine?

Wo knows... one day...
[/quote





Hi Bert
I do hope that you don't feel that my post was criticism of your effort to get as much info out to the forum readers, if so I unreservedly apologise as that was not my intention.
When we were building steam plants and running them such things as the Regner Condensation traps were available and only as the Forum advanced into Europe did these fittings became known and available, the only supplier of fittings was Cheddar and as time went on there were others now available.


I have noticed in the past some steam enthusiast at the end of a run had copious amount of milky white condensate loaded with oil lwhich to me indicated that too much oil was coming thro' the engine.


Here is a pic of my steam tug Cervia which is powered by a Stuart D10, if you notice on the funnel there is a small oil separator which has a feed over board, the engine is fed by only a whisper of oil from the lubricator which leave more or less clean exhaust condensate over board even after a full afternoon of sailing , so can you reduce the amount of oil going into the engine Also a pic of the tugs engine Stuart D10 with boiler feed pump.


Keep up your experiments with your electronics, I do hope that somebody will read them and be converted from electric buggies, aircraft, and fast electric boats.


George..








Must try to separate the blue background


/quote]

[1967Brutus]

Hi BertI do hope that you don't feel that my post was criticism of your effort to get as much info out to the forum readers, if so I unreservedly apologise as that was not my intention.When we were building steam plants and running them such things as the Regner Condensation traps were available and only as the Forum advanced into Europe did these fittings became known and available, the only supplier of fittings was Cheddar and as time went on there were others now available.I have noticed in the past some steam enthusiast at the end of a run had copious amount of milky white condensate loaded with oil lwhich to me indicated that too much oil was coming thro' the engine.Here is a pic of my steam tug Cervia which is powered by a Stuart D10, if you notice on the funnel there is a small oil separator which has a feed over board, the engine is fed by only a whisper of oil from the lubricator which leave more or less clean exhaust condensate over board even after a full afternoon of sailing , so can you reduce the amount of oil going into the engine Also a pic of the tugs engine Stuart D10 with boiler feed pump.Keep up your experiments with your electronics, I do hope that somebody will read them and be converted from electric buggies, aircraft, and fast electric boats.George..

[/size][/font]
[/size]
[/size]Don't worry, George, I did absolutely NOT take your post as criticism. To be blunt, I'm slightly autistic, leading to "explain myself" when that is not strictly needed, and sometimes people that do not know me, interprete that as me being offended, while in reality, I am not...

[/size]On the bolded: yes, that is what is being collected in the oiul separator, but that crud is NOT representative of the condensate that can be had when condensing the remaining steam.
What is important though, is that whatever is collected in the oil separator, remans there and should never be allowed to pass over into the steam exhaust.


[/size]There is a tiny bit of oil in the remaining steam, but that is so little, that the filtering method I am using, with 100% certainty catches that.

I mentioned somewhere in one of my posts in this thread "People don't pay attention"... That was not meant as an insult to anyone, just an observation.
Way I figured out that virtually ALL the oil is arrested by the oil separator was by simply keeping track of cylinder oil consumption and oil recovered from the separator. Those quantities matched so close that I was sure the oil carried off with the exhaust steam was negligable. Not zero, but so little that it won't be an issue, and condensate filters are fairly easy to construct anyway.

[/size]As for lubrication, I am aiming for approx 0,5 ml/hour, but the adjustment of the displacement oiler is very sensitive to minute adjustments, and unfortunately also very sensitive to external influences (steaming on an Autumn day of 10 deg C lubricates a LOT more than on a summers day of 20 deg C even with the same settings).

One of the things I still want to do is build a mechanically operated, properly adjustable and constant dosing pump. Plenty ideas but none that are executable with my tools and machines (or better, lack thereof... )

[/size]Brgds, Bert

[1967Brutus]

Well... resistors have arrived, and installing them took all of about 10~15 minutes:
https://www.modelbouwforum.nl/attachments/20231021_153633-1-jpg.557527/

I still need to finetune the setpoint, protect the temperature sensor a bit better against external influences, but it works fine.
As long as I set up the control such, that the gas tank maintains about 13 degrees Celsius, gas pressure remains high enough for the burner to have some headroom maintaining steam pressure at full ahead until the last drop of gas.
Works excellent, heating switches on and off on demand, the load on the LiPo is not at all noticable in the onboard voltage, and I think there is about 2,5 hours of safe steaming in the batterypack.


I'm happy...

It is easy to say "yeah, it works"... but HOW well does it work?

In the end, I did three tests of each approximately 50 minutes, taking notes every 3 minutes and changing speed every 3 minutes at the same time.
The notes were speed, gastank temperature via telemetry, and gastank temperature via IR thermometer.

First test was without heating installed. I alternated between dead slow, half and 3/4 speed (and I take care that those speeds every time use identical throttle valve positions of course). In the middle of the test, one single run full speed (3 minutes) was done. During this full speed run, the burner near immediately went to 100% and thus boiler pressure dropped below controlled range. Fuel consumption over 50 minutes was 42 gram (fairly normal), and the lowest temperature  of the gastank was about 5,5 deg C (ambient at the time was 15 degC). After the full speed run halfway through the test, the burner barely managed to keep up with 3/4 speed, but the gas temperature slowly crept back up to about 7 degrees C. Despite that, performance of the burner system noticably deteriorated (identical engine speed required progressively increasing burner outputs).


This first test showed poor correlation between telemetry read-out and IR measurement, Most likely because the waste condensate receptacle is near to the temperature probe affecting this read-out. So I placed an insulating cover made out of Balsa over the probe.


2nd and 3rd test were done the same way, BUT only alternating between half and 3/4 (no more dead slow periods) to keep up the fuel demand, and full speed runs at 15 minutes, 30 minutes and 45 minutes approximately.
Because of the insulating cap over the probe, correlation between telemetry and IR measurement was improved to the point of "usable" but still not great. Heating switched on and off during the first part of both tests, and basically remained on after approximately halfway, so there IS some form of control, but it's a bit ambiguous and I could not really see a firm correlation between boiler load and heat demand.
The setpoint of the heating was chosen such that it switched on around approx 13 degrees actual (IR) tank temperature.
Results were positive: Both tests the burner remained below 100% output even during the last full speed run (albeit barely) and in fact, during the 2nd test the burner ran out of gas within seconds after the last full speed run. Just poof, empty, sudden flame-out, no gradually dying fire: I reduced speed to half, burner responded by reducing fire, and maybe 30 seconds later the flame extinguished without first growing smaller. Just like that. Rather surprising actually, hadn't seen that before.
Both tests the IR measured temperatures by and large remained around 12~12 degrees, with outlier observations of around 9 degrees.

One thing that was interesting:
I use a 30/70 propane/butane mix. Normally the propane burns off first, leaving the Butane for last, leading to pressure, and thus performance drop.
That is the reason that I usually blow off the remains of previous session, because this is mainly Butane, and leaving that in the tank results in lower Propane content in the freshly filled tank, thus lower performance.
For the purpose of testing, the 2nd test I did NOT blow off this residue, and despite that, I had basically full burner capacity throughout the entire test.
Because I ran out of fuel at the end of 2nd test, the 3rd test was done with "fresh" 30/70 mix, so performance was better and tank temperatures remained higher, there is a visible difference, but blowing off fuel remains has become obsolete now, which is another 15~20% fuel savings overall.

Dang, this thing is going to make me RICH... (or at least less poor... )

As a side note: the third test brought the runhour counter to about 49 hours in 4 months time... As a comparison: I also am a VERY avid RC flyer, but most of my plane engines barely manage 25 hours per year.

[1967Brutus]

Yesterday I decided to "Ogre-test" the gas tank heating, by raising steam, and putting the thing at full throttle, regardless.
I had to cut back after 15 minutes because the Feedwaterpump did not even come close to keeping up by about half.


So today I found an unused Futaba S9254 (a very fast servo used for tail rotor of RC helicopters). This servo not only has about 50% more torque than the up until now used S3001 (3,3 Ncm versus 2,4 Ncm for the 3001), it also is about 4,5 times faster (0,36 sec/revolution vs 1,7 sec/rev).
The S3001 managed somewhere in the vincinity of about 600 ml/hr, so theoretically this thing should be able to do well over 2 litres per hour.


The external housing dimensions are identical, so even if the fit is not perfect (the Regner pump was made for a different servo), since the 3001 did not present any issues, the 9254 should not either.


Modification is really simple: remove the pot-meter driver, and remove the cam on the output shaft that prevents the servo from rotating continuous. All in all a 10 or 15 minute job, really not hard.
Exchanging the 3001 for the 9254 was maybe 5 minutes.


https://www.youtube.com/watch?v=t2Tgj_PLs14


So... Repeat Ogre-test


Results:
Started out with 60 grammes of gas and after raising steam and warming up the engine, full throttle it is...
Inbetween I had the time to adjust the feedpump curve to match this new pumpdrive. Turns out, the pump needed a leisurely approx 1/3 of full capacity to keep up with steamproduction at full throttle.


20 minutes in, the burner reached maximum setting (meaning the heating can't keep up, I'll get back to that). Full burner occurs at 1,4 bar.
Yet, despite the burner not being able to give it more, the boiler virtually held pressure for another 10 minutes at least.
24 minutes in, the feedwatertank reached low level, but since this was not an endurance test but a performance test, I refilled.
30 minutes in, the gas tank temperature, that remained more or less constant, started to slowly rise again, indicating that basically most of the Propane was gone from the mix. The boiler at that time was about 1,3 bar, but now started to drop a bit quicker.
35 minutes in, boiler pressure was 1,2 bar.
38 minutes in the boiler dropped to 1 bar, triggering the low pressure alarm.
near to the second exact, 40 minutes in the fuel was through, flame extinguished at a boilerpressure of 0,8 bar.


Reason the gastank heating can't keep up, is that at full ahead, apparently the burner went through about 56 grammes in 40 minutes, equalling 1,4 g/min.
The heating, at 5W was intended for about 0,8~1 g/min because so far, that had been my average fuel consumption.
Not going to do anything about that, because apart from testing, I won't be doing continuous full ahead anyway.
Going through a feedwatertank in 24 minutes means that including condensate return (estimated to be about 100~125 ml in 24 minutes), the boiler at full ahead is generating somewhere between 1,1 and 1,2 kilogram of steam per hour, and frankly, that is quite impressive for such a tiny thing.


Further, some testing revealed that the preheater has ample overcapacity, even running the feedpump at full speed the feedwater temperature did not drop, AT ALL... Funny thing: With the feedpump at full speed, and the steam engine at dead slow, all supplied steam is condensed and the venting of excess steam stops. Switching the pump back to auto (feedrate matching the boiler) steam reappears at the funnel.


All in all I'm getting happier and happier.

And as a side note (pay attention, Derek!) the S9254 is amazingly quiet, even under load:
https://www.youtube.com/watch?v=5W4O1Wt0yCk

[rhavrane]

Bonjour Bert,
Oups, I have found this servo on Internet but at a price of about 95,00 € without shipping 

[1967Brutus]

Bonjour Bert,
Oups, I have found this servo on Internet but at a price of about 95,00 € without shipping 

Yes... that is price for a new one. But it is a bit silly to buy a new one, and especially THIS one because a servo half the speed of this one can allready do the job.
Since this type is about 25 years old, it is fairly obsolete, and I have bought them used for as little as 20 Euro, although prices for 2nd hand vary with the seller of course.
The one I fitted in my boat also was one I bought used a few years ago.

But it does not HAVE to be the 9254, or even an equally fast one for that matter. Let's face it, I have almost 2,5 litres per hour pumping capacity, and that kind of water can even sustain a Stuart D10 or similar...
I am pretty sure there are OTHER servo's with similar or lower specs that can do a good job. This servo I use now, has a rotational speed of 0,36 sec for a full revolution.
Realistically I can allready run continuouls full power with about 0,6~0,7 sec per revolution.
This servo: [size=78%]D-Power 570 BB MG – Hobby-In (hobbyin.nl)[/size] would allready do the job, has metal gears and ballbearings, and can handle probably well over 7 bar (if I would have to guess, maybe up to 10 bar, but who needs that???).
It costs only €22,50 NEW...

This one can do the job as well, and only costs only €16,50: [size=78%]D-Power 555 BB – Hobby-In (hobbyin.nl)[/size]
Little bit less pressure, but should still handle 5 or 6 bar without problems.


Those are European (Dutch) store prices, I am sure both these servos can be found on the internet cheaper than that.
The Regner pump itself (the pumping part, I mean) holds out pretty good. It's a shame they don't sell the top part separately so people can use a servo of their own choice.

[1967Brutus]

This afternoon the milestone of 55 runhours was left in our wake...

https://www.youtube.com/watch?v=SszawqNUNMs

Three improvements were done in the past week
The power supply in the boat is now a stabilized 5,2V, the gas tank heating significantly improves burner performane (which in turn makes the boiler pressure more consistent), and the digital servo for the feed pump not only is quite a bit faster, it apparently also displays a much more stable performance.
All three are tiny improvements, but apparently these tiny improvements affect and amplify each other, because whichever way, I have never seen the water level so consistent and constant throughout a run.

I did not time myself this time but if I had to estimate, this was a 40~45 minute run judging by the water left in the feedwater tank, I started out with the level glass filled to the middle of the glass to my best ability, and at the end I really could not tell whether the level went up or down. To the eye it was exactly where I started out.

And as y'all can see, the boat handles really well and allows for pretty precise low speed manouvering, coming alongside the tugboat.

[1967Brutus]

As a loose remark:

Lat time out for the boat was 9 or 10 days ago, and I expected to bo sail it in the last week, so I had the boat prepared (Battery, gastank and boiler filled/charged) but the totally crap weather with little expectation for improvement...

Did not want to store the boat like that because in a week or two I have to go to sea again.

So I ran it in order to discharge the battery, burn off the gas tank filling, get some oil through the engine and some water through the boiler.


Afterwards checked boiler water quality before discarding it and found the water to be a perfectly expected 25 ppm TDS (normal value after 4 hours of steaming).


This leads me to believe that during storage there seems to be virtually zero chemical action going on, since (at least, that is my expectation) any corrosion, dezincification or other chemical process would increase this TDS value.

No shocking news whatsoever, but it is good peace of mind to know that at least short term nothing happens when a boiler is left standing with a used water filling.

I thought, some of you guys might want to know.

[rhavrane]

Bonjour Bert,
On my side, I don't mind leaving gas in a tank even for a short while but I always empty completely my boilers and let them open to let them dry.
Furthermore, I don't always use demineralized water because I have been told that it seeks to remineralize, so I mix my navigations with tap water (fortunately not limestone).
And I use my whistles to clean the ears of my fellow citizens 

[1967Brutus]

Bonjour Bert,
On my side, I don't mind leaving gas in a tank even for a short while but I always empty completely my boilers and let them open to let them dry.
Furthermore, I don't always use demineralized water because I have been told that it seeks to remineralize, so I mix my navigations with tap water (fortunately not limestone).
And I use my whistles to clean the ears of my fellow citizens 

It does... that is why I use destilled water, not demineralized.
The difference between the two is that in demineralized water, the scale forming ions are exchanged for non-scaleforming ones. Meaning it still contains ions and thus shows some form of reactivity.
Destilled water contains nothing.

But BECAUSE I use destilled water, I don't want to waste it, so I leave the water in the boiler between regular use, as the water quality remains within acceptable limits for at least 6 or 7 hours of steaming. I replace every 4 hours or so, to stay on the safe side.
As it is, I still have zero scale in my boiler, as far as I can see.

A destiller can be bought for as little as 75 Euro new (if you pay attention and shop around). I run my destiller in the weekend, when electricity is cheaper, and especially in winter the water then is for free because that thing produces a fair bit of heat, enough to make the central heating switch off, so I am not burning any gas to heat my home...

I don't use (even don't HAVE) a whistle, it's a waste of steam that I rather use to push my boat 5 cm through the water   (just kidding... Being used to ships horns, I don't like the shrill high pitched sound of steam whistles).

I normally leave the gas in the tank, but not if I have to leave my home for 2 months. You never know what will happen, I prefer to have my gas stored in approved containers when I'm not home.