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[Proteus]

looking at the 2nd instalment in Marine Modeler on the Jeti system it looks like it should be great for steam. as the Cheddar system does pressure by temperature they have a temperature probe for IC's that will work in that range, they also have a lot of other sensors and it would be simple to have a system equivalent to the Cheddar system that can be controled from the bank so you can controle the gas and the water pump check the water tanks etc witout bringing it in so it will be like your are in it. and if you are buying new equipment it would not be that expensive, I think the telemetry part would be cheaper than the price of a gas unit from Stuart system.

Proteus

http://www.puffinmodels.com/category.php?dept=202

http://www.puffinmodels.com/category.php?dept=269

[Circlip]

Wonder if anyone is working on a micro nuclear power plant?? With one of those, coupled to numerous sensors and auxiliaries you could keep yer boat out for months, nay Years   

   Regards   Ian.

[6705russell]

looking at the 2nd instalment in Marine Modeler on the Jeti system it looks like it should be great for steam. as the Cheddar system does pressure by temperature they have a temperature probe for IC's that will work in that range, they also have a lot of other sensors and it would be simple to have a system equivalent to the Cheddar system that can be controled from the bank so you can controle the gas and the water pump check the water tanks etc witout bringing it in so it will be like your are in it. and if you are buying new equipment it would not be that expensive, I think the telemetry part would be cheaper than the price of a gas unit from Stuart system.

Proteus

http://www.puffinmodels.com/category.php?dept=202

http://www.puffinmodels.com/category.php?dept=269


One thing to bear in mind is these will only work on a supply voltage up to 8.4 volt, so anything running on a 12volt is a no no.

Russ

[Proteus]

why would I want to run it off 12 volt? it's a steam boat. where talking REAL STEAM not this fake stuff.

Proteus

[6705russell]

Sorry, you will need some voltage to power it, you could take this off your receiver though, i thought they were powered direct off the battery......

Russ

[gondolier88]

Hi Proteus,

Well spotted- that <300deg.C sensor would be fantastic- I can see the link to the gas/fuel supply regulator and have an automatic regulator- servo or whatever- I'm having trouble, however, seeing how you could adapt this for feedwater auxiliaries- or am I mis-reading your original post?

Ps- I think i'd rather rely on the pressure controlled automatic gas regulator with pilot bypass from Forest Classics- it is steam after all as you said- why put electrics in there!

Greg

[Proteus]

Hi Proteus,



Ps- I think i'd rather rely on the pressure controlled automatic gas regulator with pilot bypass from Forest Classics- it is steam after all as you said- why put electrics in there!

Greg

the reason to put electrics in there is to gain controle yourself , all they will be doing is letting you see what is happening,and you operate the servo to turn the gas down or up or to open the bypass, it could even tell you by the heat of the clack valve if its pumping water or not. it uses a led sensor for rpm the same idea that they use on the gauge glass on a cheddar unit, there will be some playing about but I am shore it could be made to work as the cheddar one does or even a rod in the top of the boiler as some others do and as temp is measured by Resistance on the thermistor so the water level will be able to be found if the water is touching the rod, this was put on as an idea that I may try, it may just let you know what is happening and let you decide what to do



 Proteus
ps Greg i cannot find the boat it looks to much like the one above it

[gondolier88]

Hi Proteus,

I see now- I should have spent more time looking at the links you put up- i thought the sensors controlled the servos themselves!

Interesting thought about the check valve temp' reading.

I've been wondering for a while now if comercially available thermistors for domestic gas boilers could be used for automatic water level control ie;

Thermistor- PCB - Servo - Bypass Control Valve

I just wish I knew about basic PCB contstruction- however the guy i'm building the Victoria for is an expert in small electronics so he could probably help.

Greg

Ps- clue as to the ID of that launch; "Malaria".

[flashtwo]

Hi Greg,

Regarding using a thermistor to measure the water level in a boiler, I think you might find that there is no difference between the water and steam both being at saturation temperature.

I am working on some novel ideas regarding level measurement, but would people find it practical, if use was made of the filler cap on the boiler from which a detector could be extended to the required water level, or would you prefer to have a dedicated connection which may involve modifying the boiler?

Do you need to know the water level for feed control when the boiler is cold or only when it is steaming?

I'm not thinking of the conductivity type which is used by some model boaters, which I believe can be unreliable if the water is too pure.

I don't need to measure level on my flash boilers, but I'm intrigued that people are after a simple reliable level control system.

Regarding measuring RPM with an LED. I tried using an infra-red LED and detector, since they are more immune to ambient lighting, which was fine on the test bench. In practise I found that optics gradually got covered in a film from grease/oil and attracted dust, which made them un-reliable. I switched to a magnetic type with a small magnet fitted in a brass collar and a semi-conductor detector - they're covered in oil and just keep on working. So, if you use the LED type make sure its in a clean area.

Are these JETI modules just for sending data back to the shore? - I've looked at the website and I have missed how you actually view the data.

Ian.

[Proteus]

Hi Greg,

Regarding using a thermistor to measure the water level in a boiler, I think you might find that there is no difference between the water and steam both being at saturation temperature.

Ian.

no not using a thermistor for water level it was a stainless from the top of the boiler to the water level or as in the Cheddar ABC unit a infrared sensor,
I am using two of these without any problem at all, they are at the far end of the boiler and the engines are not that messy unless you go mad and I have a smallshroud around the bottom anyway as both the  Proteus and Gemini are messy bottom end but as I said a small shield about 25mm high keeps it in
hear is a link to the type with a rod in the top, I have one built but not tried it yet.

http://www.modelboats.co.uk/news/article.asp?sp=&v=1&uan=70

Proteus

[6705russell]

Hi Greg,

Regarding using a thermistor to measure the water level in a boiler, I think you might find that there is no difference between the water and steam both being at saturation temperature.

I am working on some novel ideas regarding level measurement, but would people find it practical, if use was made of the filler cap on the boiler from which a detector could be extended to the required water level, or would you prefer to have a dedicated connection which may involve modifying the boiler?

Do you need to know the water level for feed control when the boiler is cold or only when it is steaming?

I'm not thinking of the conductivity type which is used by some model boaters, which I believe can be unreliable if the water is too pure.

I don't need to measure level on my flash boilers, but I'm intrigued that people are after a simple reliable level control system.

Regarding measuring RPM with an LED. I tried using an infra-red LED and detector, since they are more immune to ambient lighting, which was fine on the test bench. In practise I found that optics gradually got covered in a film from grease/oil and attracted dust, which made them un-reliable. I switched to a magnetic type with a small magnet fitted in a brass collar and a semi-conductor detector - they're covered in oil and just keep on working. So, if you use the LED type make sure its in a clean area.

Are these JETI modules just for sending data back to the shore? - I've looked at the website and I have missed how you actually view the data.

Ian.

The Jeti box receives information back but its a duplex system so you can send info back in that you can alter the parameters on servos etc....

Russ

[gondolier88]

Hi Greg,

Regarding using a thermistor to measure the water level in a boiler, I think you might find that there is no difference between the water and steam both being at saturation temperature.

I am working on some novel ideas regarding level measurement, but would people find it practical, if use was made of the filler cap on the boiler from which a detector could be extended to the required water level, or would you prefer to have a dedicated connection which may involve modifying the boiler?

Do you need to know the water level for feed control when the boiler is cold or only when it is steaming?

I'm not thinking of the conductivity type which is used by some model boaters, which I believe can be unreliable if the water is too pure.

Ian.

Hi Ian, the thermistor i'm talking about is used in domestic gas combi's and is fixed into the top of the main heat exchanger, it is called a 'Dry Fire Thermistor' and sends a signal to the PCB when it detects no water around it- as it would be pretty catastrophic if a 97% efficient gas burner heated up a silicon/alluminium heat exchanger with no water in it- almost as catastrophic as it would be in a steam boiler.

I would imagine that it relies on a difference in restistance.

They prove 100% effective in gas boilers so I can't see problems arrising.

And no, Ian, in answer to your question about needing to know the water level if the boiler is cold- it is completely irrelevant what the water is doing when it's cold, as long as there's water in it when it's hot!!!

Also, people would only be able to find the use of the filler cap practical as the probe connection if they other means of injecting water into the boiler- feed pump, injector etc.- i don't think either the user or the probe would take kindly to have to keep taking it out to fill the boiler.

The most reliable means of perfect measurement of steam- hence water- consumption is to measure the flow-rate of steam through the supply pipe- on full size modern plants this is done using- if i've got it correct- a Crow's Measuring Device- kind of like a turbo in reverse- the device is inline with the main steam pipe and contains a very sensitive impellor which rotates proportionally to the rate of steam passing through- the RPM of the impellor shaft is measured and connected to a potentiometer which tells a modulating relay what to do, which then controlls the feed valve rate.

Greg