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Author Topic: LET'S FILL THE BOILER  (Read 4536 times)

John W E

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LET'S FILL THE BOILER
« on: July 10, 2007, 04:13:22 PM »

Those of you who have received this month's Model Boat magazine (August 2007) issue, will see that there is a simple Electrical diagram for making a control unit for a feed water pump for a steam boiler.

I am putting this build on the forum, so those who wish to build this circuit, who have very limited knowledge of Electronics to try and overcome some of the mysteries of the circuit.  Using the magazine and this topic, you should successfully build the circuit.

I am deliberately omitting the construction of the copper probe and fittings - because its all in the magazine.  So, let's commence.

What does it do?

Basically its an electronic switch that senses the absence of water between the probe and casing of your boiler internally and switches an electric small pump motor on.   Or, it could be made to operate an solenoid switch which in turn operates a three-way valve being fed from a mechanical pump and driven via your steam engine.

Enough of the description and let's get on with some burny fingers and get soldering;  ;D

What tools do we need first of all

Same as we normally use, 15 wat soldering iron, small pair of sidecutters, long nosed pliers, some wire wool or an old tooth brush.  A Quarter twist drill - some flux/cord solder.  Long nosed tweezers, the owld grannies clip, small crocodile clip, magnifying glass again (if you are short sighted).

Now, we have our tools, we have to get our components to build the board.    There are plenty of suppliers of electrical equipment which we will list at the end of the build.

So, what components do we require - the list is in the magazine - but, I will run through the list:

2 x 1k resistors
3 x 10k resistors
1 x 100k resistor
1 x 4M7 resistor
2 x 100nF capacitors
2 x 1N4007 diodes
1 x IRF540FET transistor
1 x LM1458  IC
Plus the IC socket
6 x Vero pins
Strip of Vero board

so these are the components we require;

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John W E

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Re: LET'S FILL THE BOILER
« Reply #1 on: July 10, 2007, 04:19:09 PM »

Lets begin the construction.

Stage One

First of all, we need the Vero board.   One side has copper tracks on, the other side is plain and its got lots of little holes in it.   Now what we need to do, is put some breaks in these tracks in certain places.  If we place the board so the copper strips face us and run from right to left and count along the holes from 1-26 marking them off, and, downwards from A-J (see attached).   Where the 'X's are marked on the plan, remove the copper track with the aid of a twist drill.   Ensure that you have no burrs left on the copper track or no shorts between tracks.   After we have finished removing the pieces marked with an X (see attached) brush over with wire wool or a stiff toothbrush to ensure the tracks are clean.
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John W E

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Re: LET'S FILL THE BOILER
« Reply #2 on: July 10, 2007, 04:37:07 PM »

Stage Two

We next start the components in.

There is no real order in which we solder the components onto the board, I only offer this as a guidance.   First of all, I started off by putting the wire links in:

Now what we do is flip the veroboard over so that the plain side faces us and the track side is on the bench.  The numbers at the top from 1-26 (i.e. 1 is on your left hand side and 26 is on your right hand side)  (A is at the top and J is at the bottom).

Now we put the links in.

First Link in - from D - E on row 3

Second Link in - from E - F on row 4

Third Link in - H-J on row 4

Fourth Link in - from A-E on row 9

These links I made out of plain copper bell wire.

The next thing I soldered in was the I.C. Socket.   Make sure you have the notch in the socket the right way.  This goes in on Row 5 - E   to  5-H and from 8- E to 8- H.    After I had soldered this in, I started on the resistors.   From 1 - R   to 7 - R.    These resistors are non-polarised and it doesnt make any difference which way round they go.   You will notice that resistor 3, resistor 5, resistor 6 and resistor 7 are soldered vertical in the board.  Whereas R1, R2 and R4 lie flat on the board.

Next I fitted the two capacitors, these again are non-polarised capacitors and it doesnt matter which way round they go.

Next, I soldered in the Zener diode.  This looks like a small glass bead with a black cap on the end of it.   It is polarised and it is critical which way it faces.   The black cap goes into Row G and onto pin 3 of the I.C.    Next I fitted the two standard diodes 1N4007.  These again are polarised and if you have a look on the drawing, you will see which way they face.

Now, we are going to fit the FET transistor, this, you need the assistance of the crocodile clip on the legs of the transistor as a heat sink.   Its a bit of a squeeze between resistor 6 and resistor 7 and only after completion of the board did I realise I could have moved R7 along a set of holes.  The last item to go in is a variable resistor RV1 as I have called it.   That is all of the components soldered in, and now there are only the Viro pins to solder in.   These I have marked with a circle with a cross in the middle.
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John W E

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Re: LET'S FILL THE BOILER
« Reply #3 on: July 10, 2007, 04:48:27 PM »

Now the board is complete, we need to do some visual checks to ensure that we havent accidentally bridged the copper tracks with solder.   I do this by running the back end of a scalple blade along the back of the copper tracks and also cleaning it with Methylated spirit and the old toothbrush, examining all my solder joints to make sure they are made properly.  We then insert the IC chip into the socket  We proceed to putting the wires onto the pins.

First of all, the power supply.   Positive goes into Pin A1, its location should be A25.  The negative wire is soldered onto the pin J24.  That is the positive & negative power supply wires.    

We now connect up the motor supply.   This pin, I have marked C2 on the plan, which is located on Row 18A.

Underneath where you see I have written C1 and actually that should read C2.  The other connection for the motor is D2 on row 25I.  These two pins and wires are connected to your motor.  The last two pins to connect up F2 and E1 are your probe wires.     These are on row 11D and 10G.

So to test it - I connected up an MFA Rocket 400 motor to represent the pump motor.  A 6 volt battery connected up and low and behold the motor actually ran.

When I stuck the probe wires into a glass of water - it switched the motor off.    What I did find was the FET transistor got extremely hot .

I hope this is of some help to you.

I also hope it inspires people to have a go - especially those who enjoy the Steam side of our hobby.

It was a very simple project to build, once we had ironed out one or two little snags.

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John W E

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Re: LET'S FILL THE BOILER
« Reply #4 on: July 10, 2007, 04:52:57 PM »

As a thought, what can the rest of us do with this circuit.

With a bit modification, which we will do on another build, we can turn this into a bilge pump for TugboatKenny & everyone who has a 'leaky' boat.  ;D

It doesnt take much modification - Ive had a talk with PMK - and when he gets his computer up and running again, he is going to come up with some modifications.   No doubt other people on the forum with electrical skills will be able to modify it themselves.

Im just going to say, THANK YOU TO THE EDITOR of Model Boats for giving his permission for me to copy the circuit and put it on this Forum.  THANK YOU TO PMK as well because he helped out a bit behind the scenes.

I bought my electical components from a Company called 'ESR Electronic Components' they are on the web - and I know Maplins  and also a Company mentioned in Model Boats Magazine who will supply the parts.

HOPE YOU HAVE ENJOYED THE BUILD & WILL HAVE A GO. ;D

Aye
John E
Bluebird
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Martin [Admin]

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Re: LET'S FILL THE BOILER
« Reply #5 on: July 10, 2007, 04:55:56 PM »


I read the article but I had bought a kit from another source some weeks ago for the one in model engineers mag they both work on the same princaple. I spoke to a few people on this subject at the time cheddar brought out there ABC system. and the problems they had with the sight glass. and most thought it would be OK as long as the probe was kept clean. so how the article writer gets on with pond water in his boiler ! I ran one of my engines on some water borrowed from someone once and it needed a strip of the pump and clean after. I will be interested to see how it works and it may spare me on to get my finger out.

Peter



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John W E

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Re: LET'S FILL THE BOILER
« Reply #6 on: July 10, 2007, 05:16:48 PM »

Hi there Peter, the thought occurred to me when I was testing it.
 
What happens with water bubbling up inside of the boiler?  Will this not switch the pump off prematurely.   
 
What happens to the water in the boiler if the boat moves from side to side, will this keep switching the pump on and off? 

Or, will the water stay level in the boiler??

aye
John
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chingdevil

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Re: LET'S FILL THE BOILER
« Reply #7 on: July 10, 2007, 06:58:55 PM »

Hi John
As I understand it water does not bubble in a boiler like it does in a kettle, this is because there is a head of pressure when the boiler is in steam which stops this bubbling. I am not sure what type of boiler you are thinking of, but a lot of boilers have the water going through tubes with some around the firebox, so I would think if the probes were in the front of the firebox the water moving about would not be too much of a problem.

Great article John, keep up the good work

Brian
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mrsgoggins

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Re: LET'S FILL THE BOILER
« Reply #8 on: July 13, 2007, 09:51:52 AM »

So many good ideas, so little time!
I have a Cheddar ABC but prefer the simplicity of this circuit. Any (simple) ideas on how I could drive the servo on my water bypass valve?
Keith
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Ian Robins

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Re: LET'S FILL THE BOILER
« Reply #9 on: July 15, 2007, 05:55:07 PM »

Hi,
there is a circuit and discription in stan brays book Steam boats and there is also one from Malcolm Beak in the paddle ducks website
ro88o0
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OMK

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Re: LET'S FILL THE BOILER
« Reply #10 on: July 16, 2007, 12:18:37 AM »

Robbo,

A few weeks ago I'm in W.H. Smith's and treated meself to a copy of Malcolm Beak's book. Thing is, I'm in the middle of moving and all my worldlies are stashed in boxes - can't find where that book is.
Do you know the address of the website?

Who is Stan Bray?


Thanks, amigo.
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HS93 (RIP)

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Re: LET'S FILL THE BOILER
« Reply #11 on: July 16, 2007, 01:10:31 AM »

Robbo,

Who is Stan Bray?


Thanks, amigo.

this is the book, dont know who he is, but I cannot find a circuit dia just a picture of it .

Peter
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roycv

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Re: LET'S FILL THE BOILER
« Reply #12 on: July 16, 2007, 09:36:58 AM »

Hi all, I designed the first of the electronic water level controllers and it was published in the now defunct Radio Control model boats in 1988.  The circuits were developed with my good friend Malcolm Beak who did all the mechanical bits!  They were for a 24 hour endurance run and we were the only steam engine entry!  We did not last long as we were run down and sunk by a very badly driven competitor.
The original idea was taken from Model Engineer an edition in 1974 I think which used the probe part of the  system as an indicator of the water level in a 5 inch gauge steam loco.  This idea just lit some led's (for night driving!) and the driver did the rest.
For the full article from 1988 you can download it from  www.paddleducks.co.uk
This was years (10, I think)  before Cheddar's own system, they rejected our set up when it was offered to them.  They said no one would be interested!
As I think has been said, their system sensed the water meniscus in the sight tube on the boiler.

Anyway to the point, the original was always intended to use pond water and over the years there was never a problem with it.  If I remember correctly the insulated water level probe was connected to the +ve and this stopped any deposit on the probe.  Malcolm still has the system in use.
One of the problems with system is that the boat moves around a lot, and later versions of the controller had a 2 second delay built in to the sensing of the probe so that a constant low water level was sensed, rather than the boiler water slopping about inside.

Others who used the system carried distilled water with them but this did not work so well until salt or perhaps vinegar is added to the water.

The original circuit incorporated a servo control circuit and this operated a by-pass valve to an engine driven boiler water feed pump.
I also made a up special with a direct motor control (relay) which got rid of a lot of circuitry.
I always like simplicity and this new circuit is quite elegant.
Regards to all Roy

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malcolmbeak

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Re: LET'S FILL THE BOILER
« Reply #13 on: July 16, 2007, 10:07:39 AM »

Hi All
As Roy says, his original system is still in regular use. He talks about a 2 second delay, but this is not quite correct. What is actually used is a variable time between zero and about 20 seconds when the pump would continue to deliver no-matter what the water level was. This stopped the continual switching in and out as the boat rocked. In practice, the water level remains constant, but in rough conditions will settle maybe an eighth of an inch lower than in calm water.
Stan Bray was for many years the editor of Model Engineer magazine. I chanced to meet him while he was writing Model Marine Steam and ended up sending him some information. (Not my book by the way) PMK. Unfortunately, his publishers cut some of the content, and also there is quite a lot of information given that I do not agree with.
Going to a previous point, water most certainly does bubble a lot in a boiler even under pressure. Peter Whalley built a boiler with a quartz end plate so he could see what went on and bubbling there certainly was. He certainly has some photos and possibly a video of what goes on. So if you put a probe in your boiler, it is a good idea to try and shroud it a bit.
If you go to the paddleducks website, then click on Downloads , Steam Engine Articles, Malcolm Beak you will find the article on level control as well as some on gas control and an engine and gearbox design.
Malcolm
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