Cringle steam turbine genset

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darwenguy

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Hi all, ive had some requests for more details of the cringle turbine model.
Il record a full build log here with plenty of photo's.
Il be making a set of 3 so you may see some parts shown more than one off.
 

darwenguy

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This is a photo of the kit as it arives, it includes all castings, barstock and fittings to finish the model.
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Il first start work on the shaft and rotor
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The 6mm stainless bar is first trimed to length, then turned the steps on the shaft.
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A little change from the drawing specs here! I could not find my m5 die nut, so ive opted to form a striaght knearl and press fit the shaft into the rotor.
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Next onto the rotor, il first rougth it to size and then finish turning the rotor after it is mounted onto the shaft.
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Faced off and clean up the chucking spigot.
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Then chuck via the spigot and turn close to final size and center drill, drill and ream 5mm.
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Thats all for today, tomorrow i will finish machining the rotors then onto the rotor housing casting.
Regards
Luke
 

darwenguy

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Today i finished making the rotors,
First removed the chucking spiggot.
then the shaft was pressed into the rotor with a little locktight using the milling machine to press in the shaft.
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The shaft was then put back on the lathe to finish the rotor to final size with very light cuts.
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Next up onto the milling machine and my homemade rotary indexer, for the 16 8mm pockets to be milled. The indexer was made from plans found on hmem forum and well worth the investment.
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The finished rotors.
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Then next onto the rotor housing.
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darwenguy

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Todays progress on the rotor housing and bearing housing castings.
The photos will explain most of the process.
First step was to machine the inner of the casting.
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Then chuck on the inner diameter and machine the rear side of the housing.
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Next part the bearing housing castings.
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And check fit!
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The bearing housing was then mounted onto a peice of bar with a m8 bolt as a super simple indexer and going off the ready marked hole positions on the casting.
20210415_142802.jpg
 

darwenguy

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20210415_144514.jpg

The bearing housing was then super-glued onto the rotor housing and the holes marked through with a 3.2mm drill and then drilled through 2.4mm then tapped m3.
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The rotor housing with the bearing housing was then mounted in the lathe to bore the rear bearing pocket.
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And thats all for today, more to come tomorrow.
 

darwenguy

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Hi, todays efforts as follows..
Did a little more on the rotor housing, milling the feet level and inlet flange. Still need to drill and tap the for the steam nozzle.
20210416_144157.jpg

Next job onto the rotor covers.
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First faced of the inner serface.
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Then drill the screw lugs through 3.2mm and drill/tap for the condensate outlet m5.
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The rotor housing was then screwed onto a solid bar to hold in the drill vice.
The front cover was then stuck to the rotor housing With a drop of superglue.
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The holes were marked through 3.2mm then drilled to depth and tapped m3.
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Thats all for today, next task is to mill and drill the exhaust flange on the front cover. More to come soon.
 

skyline1

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Fascinating little job, it's not unlike my own steam turbine generator (see my avatar or more pics of it here Genset pics

This looks like a Stumph turbine where the steam admission it is straight on tangential to the rotor. Mine is a DeLaval type where the steam comes in from the side at about 30 Degrees to the rotor

Where did you get the kit ? I might possibly have a go at one of these myself.

Doing the curved exhaust pipe looks a bit tricky, it looks like the castings aren't cored so you are going to have to somehow bore out this curved hole.

Best Regards Mark
 

darwenguy

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Fascinating little job, it's not unlike my own steam turbine generator (see my avatar or more pics of it here Genset pics

This looks like a Stumph turbine where the steam admission it is straight on tangential to the rotor. Mine is a DeLaval type where the steam comes in from the side at about 30 Degrees to the rotor

Where did you get the kit ? I might possibly have a go at one of these myself.

Doing the curved exhaust pipe looks a bit tricky, it looks like the castings aren't cored so you are going to have to somehow bore out this curved hole.

Best Regards Mark
Hi mark, i have seen the pics of your genset before now. Realy nice work! That turbine rotor is a work of art!!
Mine is much simpler and probably much less efficient.
I intend to eventually make an inline genset with the same turbine And a brushless generator.
And yes the steam is fed as you seid.
I produce the kits myself, my own design.
The front cover is cored and just requires the hole through the exhaust flange, il add more pics of the inside.
Regards
Luke
 

darwenguy

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More details of the kit here..
Fascinating little job, it's not unlike my own steam turbine generator (see my avatar or more pics of it here Genset pics

This looks like a Stumph turbine where the steam admission it is straight on tangential to the rotor. Mine is a DeLaval type where the steam comes in from the side at about 30 Degrees to the rotor

Where did you get the kit ? I might possibly have a go at one of these myself.

Doing the curved exhaust pipe looks a bit tricky, it looks like the castings aren't cored so you are going to have to somehow bore out this curved hole.

Best Regards Mark
Heres a pic of the inside..
20210417_120722.jpg

More details here...
 

darwenguy

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A bit more work done today as follows..
Finished machining of the front cover exhaust port and the brass exhaust flange. The photos best explain the process..
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The exhaust flange casting.
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First faced off then drill tap m4 for mounting onto an arbor.
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The same arbor is used on the rotary table to drill the screw holes.
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Then back to the lathe to drill and bore the center hole.
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Then mill the flat section on the flange.
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And the finished component.
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darwenguy

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And more..
The exhaust flange was used to mark the hole centers through then drilled to depth and tapped m3.
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The exhause hole was then drilled through.
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And thats all for today.
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skyline1

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Hi Luke

Aha all is revealed I had visions of hours of work with a die grinder but now I see the back of the casting it's simple.

A brushless motor is a possibility but there are a few technical problems. As far as I am aware a true brushless D.C. machine does not exist, A "brushless" motor is in fact a permanent magnet high frequency Polyphase A.C. machine (what a mouthful !) In it's normal "mode", like drones and R.C. cars it is connected to an Electronic Speed Controller (ESC) which is a micro miniaturized version of the A.C. varispeed drives you sometimes see on machine tools. What it does is to "chop" up the D.C. supply (usually from batteries) into 3 phase A.C. at variable frequency and phase rotation using semiconductor switches (F.E.T.s usually) thus you can control the speed and/or direction of the motor.

So if you couple one up to a turbine for example it will produce power but it will produce 3 phase A.C. at a frequency and voltage dependent on it's speed. Actually this is just what full size power stations do so theoretically at least, you could transform this up to any voltage you want for transmission, again just like full size practice. These motors are designed for high speed use so are ideally suited for turbines if we could get over the 3 phase A.C. problem.

The good news is WE CAN the solution is 6 small diodes and a capacitor (I'll send you the circuit if you want or just search for 3 phase bridge rectifier).

Whilst on the subject of electronics, I have all the design details for the switchboard on mine on my dropbox if it interests you Switchboard and also the LED Regulator that is inside it Regulator

I have been looking at your website and all of your model kits look very interesting. Now I know why you are making 3 of these at once. When budget permits and when I have finished the enormous Audio project I am now working on I think I will invest in one of these little turbines and you lovely little boiler to go with it.

BTW thanks for your complement on the rotor they are not too difficult to make and do not require much by way of equipment but they do need a great deal of patience. and a penchant for scraping away with needle files.

Best Regards Mark
 

darwenguy

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Thanks for the info mark.
Im actually also in the process of making a model AC generator and have here a range of bridge rectifier diodes to try and also i guess the same one as you say with the 4 diodes and a capacitor. They actually come as a little kit on ebay with all the components and a printed bord for very little money. Actually there single phase! sorry, so yes the 3 phase diagram would be intersting to see.
My ac generator build is in the 'work in progress' section.
I have got my head around the basics of generators now i think. For the inline genset im thinking i think there called diametrical cylinder magnets and a simple single phase winding witch would ofcorse make AC so rectification would be more efficient.
The DC dynamo on this model is just a simple small dc motor in a fancy shell.
I do like your switch bord, the whole model looks great and im going to make somthing simular i have been colecting little ols style voltage meaters and they would look great with your switches on a panal.
Thanks the website is still new, im still working on more models to add to the range. And thanks the boilers have been very popular.
I can see the effort put into your rotor, it looks like is it two plates with the vanes cut then twisted and layerd then rivets and soldered the ring on. You must have great patiance!! Well done.
 

skyline1

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Hi Luke

Here you go

3P bridge.png


This is the circuit for a 3 Phase bridge. As you can see it is much like a single phase one except there are 2 extra diodes.

You say your dynamo is just a small D.C. motor in a fancy shell so is mine, we seem to think alike in these things.

I was thinking about taking some old meter movements out of their cases, shortening the needles and mounting them in some little 3d printed ones that look like the old "half moon" ones you see on old electrical gear. These little meter movements are very sensitive 50 microamps typically so even at this scale they won't load the output down. I might try it sometime if I can find time amidst the myriad other projects.

I've got real working Knife switches so why not real working meters and whilst I'm at it I'll make some handles for the rheostats on the switchboard, they work too BTW thanks to some modern electronics I can dim the lights or bring them up as I want.

You are right about the rotor that is pretty much how it is made. markout and cut the two discs (one needs to be offset by the thickness of the metal so they line up) anneal them, dish the blades (I've got a tiny press tool for that, for press read vice), then anneal again and twist them, tweak them into line as the twisting distorts them a little, then the edges need to be sharpened so the blade has a crescent moon shape, clamp them on the shaft with the collars, drill through and rivet the whole lot together then secure the shroud and solder it on.

Then comes balancing them, that will REALLY try your patience, or turn you into a gibbering idiot ! But it is vital for performance at the speeds these things can achieve, about 30,000 RPM in my case and that's ON LOAD.

I used to test Rotating Electrical Machines for a living at one time so if there is any help I can give you with them please ask. I might not know the answer but there is very likely someone on here who does. There a number of threads on the subject and some very knowledgeable people.

Best Regards Mark
 

Steamchick

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Mark, an excellent job! I do like the 2-tier modelling mounting so you display the turbine floor, complete with switchboard (where is the operator?) And with the hand water pump, gas valve etc mounted beneath for the fireman to operate descretely.. However, when sitting at the bench operating those controls the pressure gauge, water gauge, and any electrical meters are not directly in view. That has given me some things to think about for my genset layout....
Well done anyway. The generator casing looks very authentic. Just needs the steam plumbing to be lagged with white cotton string and painted with household emulsion paint to look like white insulation.
Regards,
K2
 

skyline1

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Hi Luke

Great idea, In fact the steam pipe was originally lagged in just this manner but I had to take it for off for some reason during one of it's many modification rebuilds and forgot to put it back on again.

This turbine, like yours I expect, was not exactly designed from the get-go. It sort of evolved through many experiments and tweaks. Not all of them were successful, indeed some were outright failures.

I am not alone in this however as even today turbines are a little experimental and unpredictable, and on a small scale like this even more so.

Both Gustav DeLaval and Algernon Parsons had their share of "epic fails" and Sir Frank Whittle had some spectacular, explosive ones,


I eagerly await the steam nozzle bit of your project as this is a VERY critical component and I had several tries before I got it just right.

turbine-steam-De-Laval-nozzle-jet-wheel.jpg


Ideally it should be like this. and getting the throat diameter just right is tricky, too small and you don't get enough steam flow, too large and you get plenty of flow but not enough velocity.

You will soon know when you do get it right, as I did !

In early days of testing the turbine I was running it unloaded testing various nozzle sizes and Geometries and one day as I slowly increased steam pressure it suddenly hit a point when it accelerated wildly and then suddenly became much quieter. It was drowned out by the sound of every Dog, Cat, Sheep, Bird and other sundry creatures within about 1/2 a mile making the most horrendous racket.

What had happened (As I found out later) is that it was going so fast that it's blade frequency had actually gone ultrasonic, I couldn't hear it but all the animals could !

I Suspect you now suffer from a condition called "Turbinitus" I also have it. It's quite incurable, and rather contagious, but great fun if a little frustrating at times.

So keep at it and I can't wait to hear 'em spin up for the first time.

Best Regards Mark
 

darwenguy

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Hi all, got some hours done today, making the steam nozzle and the steam inlet flange.
The steam flang machined as follows.
20210417_135703.jpg

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Then onto an arbor with 4mm stud to turn the other side.
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Then on the mill to drill the screw holes 3.2mm.
20210418_111308.jpg

To finish the outer profile i use another arbor on the lathe(a brass offcut with holes tapped). If i was just making one piece i would probably just file this to a oval profile.
20210418_112719.jpg

The parts were then drilled through 4mm and a little cleanup.
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The inlet flange was then used to mark the holes on the rotor housing, then drill/tap for the screw holes and steam nozzle.
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darwenguy

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Next i made the steam nozzle.
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First turned and thread m6 and a small center drill makes a nice nozzle opening.
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After parting off and drilling through from the other end the slot was formed on the mill.
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The finished nozzles and how they fix into the housing..
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Il make the drive pully tomorrow and give them a spin test. oh and i still need to make the oil cup and hole in the bearing housing.
20210418_135115.jpg
 

darwenguy

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Hi Luke

Great idea, In fact the steam pipe was originally lagged in just this manner but I had to take it for off for some reason during one of it's many modification rebuilds and forgot to put it back on again.

This turbine, like yours I expect, was not exactly designed from the get-go. It sort of evolved through many experiments and tweaks. Not all of them were successful, indeed some were outright failures.

I am not alone in this however as even today turbines are a little experimental and unpredictable, and on a small scale like this even more so.

Both Gustav DeLaval and Algernon Parsons had their share of "epic fails" and Sir Frank Whittle had some spectacular, explosive ones,


I eagerly await the steam nozzle bit of your project as this is a VERY critical component and I had several tries before I got it just right.

View attachment 124590

Ideally it should be like this. and getting the throat diameter just right is tricky, too small and you don't get enough steam flow, too large and you get plenty of flow but not enough velocity.

You will soon know when you do get it right, as I did !

In early days of testing the turbine I was running it unloaded testing various nozzle sizes and Geometries and one day as I slowly increased steam pressure it suddenly hit a point when it accelerated wildly and then suddenly became much quieter. It was drowned out by the sound of every Dog, Cat, Sheep, Bird and other sundry creatures within about 1/2 a mile making the most horrendous racket.

What had happened (As I found out later) is that it was going so fast that it's blade frequency had actually gone ultrasonic, I couldn't hear it but all the animals could !

I Suspect you now suffer from a condition called "Turbinitus" I also have it. It's quite incurable, and rather contagious, but great fun if a little frustrating at times.

So keep at it and I can't wait to hear 'em spin up for the first time.

Best Regards Mark
Hi mark i think there a little confusion with the replys here.
A lot of info there thanks, but i just have no time for starting new projects at the minute far too many already ongoing.
Yes i did have a go with a few different rotor tests before i settled on this design as its simple easy to draw and machine and cast the parts.
Its more of a simple pelton wheel type, the steam is actually fed to the side of the the slots and is forced in a u-turn to exit this increases the power from the steam as its still expanding.
The nozzle again is very simple, i tried a few different designs also to settle on this one. it narrows down to 1mm with just a small 1mm center drill used that also opens the end up to a slight funnel.
The pics will explain better than my words.
I have made around 30 of these models now and they run quite smooth on little steam pressure and im guessing about 25k rpm.
Il assemble them and do some test on air tomorrow and try to get a video they do sound great throtleing up :)
Regards
Luke
 
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