Author Topic: water Mill restoration  (Read 459 times)

Offline smiffy

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water Mill restoration
« on: November 03, 2018, 06:08:46 PM »
For nearly a year I have been restoring  a 1790 water mill that belongs to a friend . This is a 2 stone mill  driven by a undershot wheel .
There is also a turbine which I have reinstated
All the work is being done single handed so progress is fairly slow and as this is a private project funds are limited.
The pictures here are of the francis turbine which has a 24 inch runner and works at a head of 5 feet .
All the bearings are lignum vitea and I have used all the original ones as new lignum vitea is almost unobtainable 
 My objective is to be able to produce flour some time next year

Offline charadam

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Re: water Mill restoration
« Reply #1 on: November 03, 2018, 06:56:57 PM »
Where are you in the world?

A location might well produce volunteers, cash, or lignum vitae bowls (bowling green type) that might do for replacement bearings.

I would volunteer if you are not too far away from Wem, Shropshire.

Online WeldingRod

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Re: water Mill restoration
« Reply #2 on: November 04, 2018, 03:51:58 PM »
There's a gent supplying lignum vitae bearings for engineering applications, and growing the next generation...  ran across it in the ASME magazine a few years ago.

Sent from my SAMSUNG-SM-G891A using Tapatalk


Offline smiffy

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Re: water Mill restoration
« Reply #3 on: November 12, 2018, 02:51:12 PM »
A few more pictures of the francis turbine . The first thing was to split the drive shaft and remove the coupling then remove the thrust pad and thrust bearing that is a block of lignum vitae 
Then I removed the spider which controls the opening of the vanes . This took some considerable time as everything was seized solid .
Then it was possible to remove the top plate and expose the vanes and central runner .
The years of water running  through it had formed very hard limestone scale that made dismantling very difficult .
  Thanks for the idea of using bowling balls but unfortunately they are way too small as the main thrust bearing would require a cubic foot which would be available but  at great cost

Offline AdeV

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Re: water Mill restoration
« Reply #4 on: November 12, 2018, 04:52:08 PM »
That's some proper old school engineering there! What are the cups made of in the turbine, they look like cast iron - if so, that would be absolute cutting edge technology for 1790?
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline smiffy

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Re: water Mill restoration
« Reply #5 on: November 12, 2018, 05:33:09 PM »
The turbine was installed in 1907 to to power a generator to provide electricity to a local house for a set number of hours each week . There were also 2 electric bread ovens installed in the mill  . Unfortunately both generator and ovens are long gone .
Before the turbine was installed there had been a small undershot wheel driving one set of stones .
 At the other end of the mill is the larger wheel driving 2 sets of stones .

The turbine runner  is the most  fantastic casting , all the other runners I have seen have pressed steel buckets but this is all one casting.

 The other pictures show the bearing housing which sits on top of the spider frame . The whole weight of the shaft and runner is carried on the wooden thrust bearing  This housing also houses 3 radial bearings  The reason why the turbine stopped working is probably because this housing was broken .
 I repaired it with strong backs to secure the 3 radial  bearing   
The original bearing retaining plates had been held in by 4  3/8  bolts on each of the bearings . these had all sheared and the whole assembly tied together with a thin steel strap

The other photo is of the operating gear . This turns the spider to open or shut the input vanes  The original was missing so I cut the ew gear out of 15 mm plate a welded 3 pieces together

Offline charadam

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Re: water Mill restoration
« Reply #6 on: November 12, 2018, 07:44:34 PM »
Smiffy,

Maybe the bearings could be made in this fashion, rather than a solid sizeable lump of LV?

https://lignumvitaesolutions.com/products/marine/stern-tube-bearings/

Offline vintageandclassicrepairs

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Re: water Mill restoration
« Reply #7 on: November 13, 2018, 03:13:08 PM »
Hi Smiffy,
I'm really enjoying seeing the progress on the mill  :clap:

From what I can see in the photo of the turbine wheel, the end of the shaft (bottom end?)
looks to be worn down to approx half its original size?
If there was that much play in the rotating shaft and wheel was there any contact wear between the turbine
blades and housing?
The inlet guide vane mechanism design is very similar in principal to the Gas turbines I worked on !!

John

Offline smiffy

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Re: water Mill restoration
« Reply #8 on: November 16, 2018, 05:19:01 PM »
The spigot on the end of the rotor shaft is not a bearing ,it locates in light cast iron cross piece in the output tube and once the main bearings are set it should not make contact with anything   . I have not got any pictures of the support cross piece as it was always under water 
At some time the bearings had got out of order and that is possible when the shaft became worn
As I have mentioned before the main shaft is supported on 1 main thrust bearing and 3 radial bears on the turbine .

The main shaft is  2 pieces of 3 inch sold bar joined in the middle . The top of the shaft is supported in a plain bronze pillow block bearing
The photos show the bearing housing and the retaining plate which had come adrift because the bolt had sheared.
 
I have also started to make a new gear to replace the cast bevel gear which is called a wallower 
To make the gear I am going to fabricate it and started by making the teeth by sawing at 30 degrees 5 inch lengths of 45 mm x 45 mm
solid bar  I did it in my old power hacksaw as it gave a better finish than my friends all singing and dancing cnc band saw
It took 10 hours to cut 44 teeth