On Sat, 16 Jul 2011 01:09:32 -0700, harry wrote:

On Jul 15, 10:16Â*pm, Gib Bogle wrote:
On 7/16/2011 12:54 AM, Andy Breen wrote:

On Fri, 15 Jul 2011 05:05:17 -0700, Matty F wrote:

shurely shome mistake

Boilers are not cast iron just for starters

Not (usually..[1]) in locomotive applications for many years, but it
was the standard material for many boilers - including locomotive
ones back in the earlies.

The first commercially successful locomotives - and the first
exported - had cast iron boilers, after all..

Pretty hard to cast a boiler, shirley?

No they were very common for low pressure steam heating of buildings pre
WW2 especially in America,
The technology is still in use but only for water boilers.

They use similar technology to cast iron radiators. Trevethicks first
loco in Merthyr Tyfil had a cast iron boiler apparently. But it was very
low pressure.

Between 35 and 50 psi are the figures I've seen quoted. These were very high
pressures for the day (and would remain respectable for another 35-odd years
in railway applications).

The thing only ran at 2mph.

It was geared down for low speed. Hauling unsprung waggons on plate rail,
you'd not want to go faster. Speeds of 3-5mph or so were typical for plateway
locomotives, certainly as long as cast-iron plates stayed in use (say
1850s at Dowlais). You'd not want to go faster, given that you needed to carry
platelayers on the train to replace the rails that had broken under you..

It's often forgotten that the Pen-y-Darren machine was not designed as a
locomotive, but was an adaptation of a multi-purpose stationary engine.
Nonetheless, it managed the longest continuous run undertaken by any
locomotive until 1825..


--
From the Model M of Andy Breen, speaking only for himself

On Sat, 16 Jul 2011 02:33:21 -0700, Andy Dingley wrote:

On Jul 16, 10:24Â*am, Guy Gorton wrote:

Then again, early stationary engines normally ran at a maximum
of about 3 or 4 psi.

That seems very low.

No, this was the sort of pressure used. Early boiler feedwater wasn't
pumped in, it was fed by a gravity cistern up in the rafters of the
engine shed (it was raised here by the pumping engine itself).


but, as stated, Trevithick used much higher pressures - not least because
his engines did most of their work via steam pressure, not vacuum)

Filling locomotive boilers against ~50psi pressures in the earlies was
a problem. Trevithick seems to have tried a pump on the Pen-y-Darren machine,
but makes much of not needing to use it (there were real issues with
pump-feed until Stephenson's invention of the pet-cock to prevent locking,
somewhere about 1820s - it may be Trevithick didn't want to risk working the
pump..).
The Middleton machines were filled before the start of a run, then blown down
at the end of it and refilled. The refil /may/ have been with cold water at
first, but the time needed to raise steam again (don't even think of the
thermal stresses on a cast boiler being refilled with cold water!) meant
that they shifted to boiling-water feed from lineside 'kettles' very soon.
These 'kettles' seem to have been a common factor across most early locomotive
applications, although Chapman and Buddle did use feed water heaters on the
engine (as well as or instead?).
Even after the pet-cock came in and allowed the boiler to be refilled while
the engine was working, hot feed from a kettle to the feed-tank seems to
have been the norm until the bigger and more efficient boilers introduced
by Hackworth (1827 on Royal George) and Stephenson (1828-1829) came in.

There's a thought on operation: fill the boiler, wait until you have pressure.
Now tie the safety valve hard down, get moving. At the end of it, release the
valve, blow down the boiler and gravity-feed with boiling water. All with a
cast boiler. The Middleton machines worked like that for over 20 years..

--
From the Model M of Andy Breen, speaking only for himself

On Sat, 16 Jul 2011 12:34:05 +0100, Clive wrote:

In message
,
Andy Dingley writes
The distinction in strength between Newcome or Watt's boilers and the
first high-pressure boilers (such as Trevithick''s "strong steam" of
25psi) is that the newer boilers also had a margin of safety over-
design to them. Trevithick knew that safety valves were unreliable and
often adjusted by enginemen (this wasn't even seen as a bad practice at
the time), so he not only designed for 25psi, but he designed to not
fail at 25psi, and to survive overpressure too.
Very low pressures are entirely feasible considering that the steam was
only used to raise a piston which through a beam allowed what it was
working on (Man engine etc.) To drop, the steam was the condensed by
spraying in cold water and the atmospheric pressure on the other side of
the piston did the work.

Use of vacuum as an important part of the working cycle wasn't banished by
Trevithick either: his most effective and longest-lasting engine type, the
Cornish mine engine, used high-pressure steam on one side of the piston and
vacuum on the other - made it a very efficient power source for its
day.

--
From the Model M of Andy Breen, speaking only for himself

On 16/07/2011 11:27, polygonum wrote:
On Sat, 16 Jul 2011 09:02:27 +0100, harry wrote:

On Jul 15, 8:23 pm, Andy Dingley wrote:
On Jul 15, 2:06 pm, harry wrote:

If a fuseable plug is in good order and fails,normally it will put the
fire out.
They are designed to do just that.

Rubbish, but then it's an AOL poster.

They can get blocked and this may not be seen if they are not removed
and examined as they should be annually.

According to several operating practices (depending on whether you're
boat or rail, US or UK) they're inspected monthly and may be
_replaced_ every six months (depending on the number of days in steam).

You are in cloud cuckoo land. Stationary boilers are often
continuously fired for months at a time .
They are only used in solid fuel boilers where it's not possible to
have an instant shutdown in the event of low water.

The mass of burning coal is swiftly extinguished by steam if the plug
melts.

Gas and oil fired steam boilers don't need them.

And I thought throwing steam onto hot coal/coke was the way to make
producer gas?

The endothermic reaction of steam with hot coke is why a bed of hot coke
cools down quickly when exposed to steam. But you're right, a byproduct
is a lot of hydrogen and carbon monoxide...

C(s) + H2O(g) + heat - H2 + CO

--
Jeremy Double {real address, include nospam}
Rail and transport photos at
http://www.flickr.com/photos/jmdoubl...7603834894248/

On Jul 16, 10:24*am, Guy Gorton wrote:
On Fri, 15 Jul 2011 15:17:08 +0100, John Williamson





wrote:
Andy Breen wrote:
On Fri, 15 Jul 2011 06:12:52 -0700, harry wrote:

On Jul 15, 1:54 pm, Andy Breen wrote:
On Fri, 15 Jul 2011 05:05:17 -0700, Matty F wrote:
shurely shome mistake
Boilers are not cast iron just for starters
Not (usually..[1]) in locomotive applications for many years, but it
was the standard material for many boilers - including locomotive ones
back in the earlies.

The first commercially successful locomotives - and the first exported
- had cast iron boilers, after all..

[1] Does the replica of the Gateshead machine that masquerades as the
Pen-y-Darren machine have a cast boiler? Trevithick certainly used
'em..

I think you will find they were wrought iron for many years. *Merthry
Tydfil was renouned for it's wrought iron.

Coalbrookdale, OTOH, was a specialist in casting. Pretty sure the
Trevithick stationary engine in the Sci. Mus. - that kissing-cousin
of Catch Me Who Can - has a cast boiler.

Don't forget that when that was designed, 10 psi was an amazingly *high
boiler pressure. The replica of Stephenson's Locomotion on the Waggonway
at Beamish has a modern boiler made of modern materials but looks like
the old design, and runs at twice the original pressure. Its safety
valve is set to blow at 15 psi.

As far as I know, locomotives all had wrought iron boiler barrels from
the earliest days, with stationary engines using cast iron for parts of
theirs. Then again, early stationary engines normally ran at a maximum
of about 3 or 4 psi.

That seems very low. *My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.
So the cast iron boiler on the ground floor of my house *is under
about 15 ft of head from the loft cold tank, which equates to around 7
lbs/sq. in.
What have I got wrong?

Guy Gorton- Hide quoted text -

- Show quoted text -

No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.
http://en.wikipedia.org/wiki/Atmospheric_engine

On Jul 16, 1:07*pm, Andy Breen wrote:
On Sat, 16 Jul 2011 02:33:21 -0700, Andy Dingley wrote:
On Jul 16, 10:24*am, Guy Gorton wrote:

Then again, early stationary engines normally ran at a maximum
of about 3 or 4 psi.

That seems very low.

No, this was the sort of pressure used. Early boiler feedwater wasn't
pumped in, it was fed by a gravity cistern up in the rafters of the
engine shed (it was raised here by the pumping engine itself).

but, as stated, Trevithick used much higher pressures - not least because
his engines did most of their work via steam pressure, not vacuum)

Filling locomotive boilers against ~50psi pressures in the earlies was
a problem. Trevithick seems to have tried a pump on the Pen-y-Darren machine,
but makes much of not needing to use it (there were real issues with
pump-feed until Stephenson's invention of the pet-cock to prevent locking,
somewhere about 1820s - it may be Trevithick didn't want to risk working the
pump..).
The Middleton machines were filled before the start of a run, then blown down
at the end of it and refilled. The refil /may/ have been with cold water at
first, but the time needed to raise steam again (don't even think of the
thermal stresses on a cast boiler being refilled with cold water!) meant
that they shifted to boiling-water feed from lineside 'kettles' very soon..
These 'kettles' seem to have been a common factor across most early locomotive
applications, although Chapman and Buddle did use feed water heaters on the
engine (as well as or instead?).
Even after the pet-cock came in and allowed the boiler to be refilled while
the engine was working, hot feed from a kettle to the feed-tank seems to
have been the norm until the bigger and more efficient boilers introduced
by Hackworth (1827 on Royal George) and Stephenson (1828-1829) came in.

There's a thought on operation: fill the boiler, wait until you have pressure.
Now tie the safety valve hard down, get moving. At the end of it, release the
valve, blow down the boiler and gravity-feed with boiling water. All with a
cast boiler. The Middleton machines worked like that for over 20 years..

--
From the Model M of Andy Breen, speaking only for himself

I think some early locomotive had a hand pump for feedwater. Modified
village well pump sort of thing.

On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in.

--
Graeme Wall
This account not read, substitute trains for rail.
Railway Miscellany at www.greywall.demon.co.uk/rail

On Sat, 16 Jul 2011 11:12:48 -0700, harry wrote:

On Jul 16, 1:07Â*pm, Andy Breen wrote:
On Sat, 16 Jul 2011 02:33:21 -0700, Andy Dingley wrote:
On Jul 16, 10:24Â*am, Guy Gorton wrote:

Then again, early stationary engines normally ran at a maximum
of about 3 or 4 psi.

That seems very low.

No, this was the sort of pressure used. Early boiler feedwater wasn't
pumped in, it was fed by a gravity cistern up in the rafters of the
engine shed (it was raised here by the pumping engine itself).

but, as stated, Trevithick used much higher pressures - not least
because his engines did most of their work via steam pressure, not
vacuum)

Filling locomotive boilers against ~50psi pressures in the earlies was
a problem.

chomp

Even after the pet-cock came in and allowed the boiler to be refilled
while the engine was working, hot feed from a kettle to the feed-tank
seems to have been the norm until the bigger and more efficient boilers
introduced by Hackworth (1827 on Royal George) and Stephenson
(1828-1829) came in.

There's a thought on operation: fill the boiler, wait until you have
pressure. Now tie the safety valve hard down, get moving. At the end of
it, release the valve, blow down the boiler and gravity-feed with
boiling water. All with a cast boiler. The Middleton machines worked
like that for over 20 years..


I think some early locomotive had a hand pump for feedwater. Modified
village well pump sort of thing.

They did, but there were still problems with the pump locking. To quote:
"..an incurable defect in the feed-pumps of locomotive engines, for the
pumps could not be made to keep in action, as they were fixed close to
the boiler, and hot water entering from the leaking of the valves, causing
them to be filled with steam instead of water at each stroke; thus preventing
them forcing any water into the boiler.." (W.P. Marshall, writing in 1849
"under the direction of Robert Stephenson", and cite don p.310 of Andy Guy's
paper in Early Railways 4)

The pet-cock, introduced - apparently by George Stephenson - in about 1815
(I mis-recalled above, when I said about 1820) allowed the pump to fill the
boiler without pressure having to be blown down (though pumps were still
regarded as "precarious" as late as 1857 - Templeton)

--
From the Model M of Andy Breen, speaking only for himself

On Sat, 16 Jul 2011 11:07:33 -0700, harry wrote:

That seems very low. Â*My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.
So the cast iron boiler on the ground floor of my house Â*is under
about 15 ft of head from the loft cold tank, which equates to around 7
lbs/sq. in.
What have I got wrong?

Guy Gorton- Hide quoted text -

- Show quoted text -

No that is correct. They had huge pistons and very long strokes.
Early steam engines actually ran on vacuum.

Except, of course, for Trevithick, and anyone else utilising his patent
(all early locomotive builders, for example..). Trevithick engines ran
on "strong steam" - 35psi plus, often didn't use condensers, derived
all power from the force (and a little bit of expansion) of the steam
and generally had small pistons (8.25" diameter in the Pen-y-Darren
machine - one of the few things we know for sure about its design).
Cylinders were still very long in early Trevithicks (4'6" in the
Pen-y-Darren machine) though some of this would have been to cope
with condensation in the cylinder (no drain cocks in those days).

--
From the Model M of Andy Breen, speaking only for himself

"The Natural Philosopher" wrote in message
...
Guy Gorton wrote:
On Fri, 15 Jul 2011 15:17:08 +0100, John Williamson
wrote:

Andy Breen wrote:
On Fri, 15 Jul 2011 06:12:52 -0700, harry wrote:

On Jul 15, 1:54 pm, Andy Breen wrote:
On Fri, 15 Jul 2011 05:05:17 -0700, Matty F wrote:
shurely shome mistake
Boilers are not cast iron just for starters
Not (usually..[1]) in locomotive applications for many years, but it
was the standard material for many boilers - including locomotive
ones
back in the earlies.

The first commercially successful locomotives - and the first
exported
- had cast iron boilers, after all..

[1] Does the replica of the Gateshead machine that masquerades as the
Pen-y-Darren machine have a cast boiler? Trevithick certainly used
'em..
I think you will find they were wrought iron for many years. Merthry
Tydfil was renouned for it's wrought iron.

Coalbrookdale, OTOH, was a specialist in casting. Pretty sure the
Trevithick stationary engine in the Sci. Mus. - that kissing-cousin
of Catch Me Who Can - has a cast boiler.


Don't forget that when that was designed, 10 psi was an amazingly high
boiler pressure. The replica of Stephenson's Locomotion on the Waggonway
at Beamish has a modern boiler made of modern materials but looks like
the old design, and runs at twice the original pressure. Its safety
valve is set to blow at 15 psi.

As far as I know, locomotives all had wrought iron boiler barrels from
the earliest days, with stationary engines using cast iron for parts of
theirs. Then again, early stationary engines normally ran at a maximum
of about 3 or 4 psi.

That seems very low. My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.
So the cast iron boiler on the ground floor of my house is under
about 15 ft of head from the loft cold tank, which equates to around 7
lbs/sq. in.
What have I got wrong?


I think you haven't got anything wrong at all.

Remember the very FIRST steam engines were atmospheric engines, So the
maximum cylinder pressure was about 14psi!

Remember that atmospheric engines worked on a partial vacuum not on a
pressurised boiler or cylinder.

In message , Andy Breen
writes
The pet-cock,
Any similarity between this and the modern clack valve?
--
Clive

On Sat, 16 Jul 2011 20:49:23 +0100, Clive wrote:

In message , Andy Breen
writes
The pet-cock,
Any similarity between this and the modern clack valve?

As I understand it, the pet-cock was for bleeding steam off from the
pump: "by opening (the pet-cock) the steam in the pump was let out, and
the action renewed" (Marshall, again).

I'd not expect a direct similiarity to anything on a "modern" steam engine,
as even the ones that use hot feed and pumps have the pump well away
from the boiler (and seals are much better, anyway)

--
From the Model M of Andy Breen, speaking only for himself

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Matty F
saying something like:

I have recently moved to Afghanistan, where this miniature steam
engine is on static display and never fired up. I have decided to make
a new pipe out of wood, as nobody will know the difference.

Taliban, Ahoy!

On Jul 16, 7:07*pm, harry wrote:
On Jul 16, 10:24*am, Guy Gorton wrote:

No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine


FFS! Don't believe _anything_ on Wikipedia!

On 16/07/2011 21:27, Andy Dingley wrote:
On Jul 16, 7:07 pm, wrote:
On Jul 16, 10:24 am, Guy wrote:

No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine


FFS! Don't believe _anything_ on Wikipedia!

Wikipedia is a lot more reliable than many other sources of information,
IMX, especially for non-controversial technological subjects. It stands
up particularly well when compared with British newspapers, for instance.

--
Jeremy Double {real address, include nospam}
Rail and transport photos at
http://www.flickr.com/photos/jmdoubl...7603834894248/

In article , Thomas Prufer
scribeth thus
On Fri, 15 Jul 2011 10:39:48 +1200, Gib Bogle wrote:

You must be new here.

Naaah.

Matty IS someone working in a museum, who repairs
ancient things, and the boiler he's talking about is undoubtedly a
restoration job.

I know, I know:-) Take a look at the post I was responding to...

*I* think Matty should just talk to the expert welder. One man I knew was an
expert welder, as in had a license to prove it. To keep it, he'd be called in
every two years, and would be given a welding job at random, like "eight-inch
steel steam pipe, overhead weld" and the equipment he had to use, like gas or
stick. They'd then X-ray the weld and cut it open, looking for faults. His boss
would hire him out to other companies when there was tricky work to be done.

One of the more memorable jobs he told me about was was a welding a copper cross
for a church roof out of thick, solid copper bars. So: big TIG welder,
water-cooled tip, and two guys with big gas torches heating the copper so the
TIG had a chance. Add a bucket of cold water on each side to dip his gloves in
every so often, and double leathers.


And it took the Pikey's all of ten minutes to nick the lot;!...

Thomas Prufer

--
Tony Sayer

Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in.

32.2 & 14.4 rings a bell..

On Sat, 16 Jul 2011 22:40:07 +0100, The Natural Philosopher
wrote:

Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in.

32.2 & 14.4 rings a bell..

14.7 rings it better unless you're somewhere up a mountain.

On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

On Jul 16, 10:24*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! *Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders. When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would operate the valves manually. A big advance
was automatic operation.

Don't you know anything?

On Jul 16, 11:03*pm, Charles Ellson
wrote:
On Sat, 16 Jul 2011 22:40:07 +0100, The Natural Philosopher

wrote:
Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. *My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in..

32.2 & 14.4 rings a bell..

14.7 rings it better unless you're somewhere up a mountain.

NPT = 1013 millibars at sea level. We've gone metric, haven't you
heard?

It was supposed to be 1000mb but Napoleon's scientists got it wrong.

On 16/07/2011 22:40, The Natural Philosopher wrote:
Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in.

32.2 & 14.4 rings a bell..

Standard atmospheric pressure (but not for thermodynamic measurements)
is 1.01325 bar, 760 mmHg or about 14.7 psi.

This will raise water about 10.2 m or 33ft 9in, assuming the figure I
looked up for the density of mercury is correct.

Of course, actual atmospheric pressure varies from day to day.
--
Jeremy Double {real address, include nospam}
Rail and transport photos at
http://www.flickr.com/photos/jmdoubl...7603834894248/

Jeremy Double wrote:


Of course, actual atmospheric pressure varies from day to day.

Leading to the first recorded instance of the phrase 'wrong sort of
weather' to explain the uselessness of the early steam engines, later
used by every British railway (with variations) ;-)

In message
,
harry writes
On Jul 16, 11:03*pm, Charles Ellson
wrote:
On Sat, 16 Jul 2011 22:40:07 +0100, The Natural Philosopher

wrote:
Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. *My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq.in.

32.2 & 14.4 rings a bell..

14.7 rings it better unless you're somewhere up a mountain.

NPT = 1013 millibars at sea level. We've gone metric, haven't you
heard?

It was supposed to be 1000mb but Napoleon's scientists got it wrong.

Not french by any chance, are you harry?


--
geoff

On Jul 16, 10:17*pm, Jeremy Double wrote:
On 16/07/2011 21:27, Andy Dingley wrote:

FFS! *Don't believe _anything_ on Wikipedia!

Wikipedia is a lot more reliable than many other sources of information,

Wikipedia can work well on narrow topics, usually where one or two
competent editors have written an article from scratch and it hasn't
yet been eroded. On anything broad-scale though, every idiot with a
coffee table encyclopedia of steam engines gets to play with it. The
top-level articles on Wikipedia are almost all dreadful - certainly
those on broad engine types or boilers.

On Jul 16, 12:51*pm, Andy Breen wrote:

How hard is it to cast a cylinder anyway? They'd been doing it for years.

Have you read Rolt's Tools For The Job? A good explanation of just
how difficult cylinders were to make, and why the inability to make
them held up steam engine development for so long. For some years
there was only one foundry (John Wilkinson) that could cast a cylinder
that was acceptably cylindrical, and one boring engine that could
machine them. Watt's first commercially working engine (at Kinneil)
had a cylinder cast of block tin, rather than iron, because it was so
difficult to make usable iron cylinders.

On Sun, 17 Jul 2011 03:52:37 -0700, Andy Dingley wrote:

On Jul 16, 12:51Â*pm, Andy Breen wrote:

How hard is it to cast a cylinder anyway? They'd been doing it for
years.

Have you read Rolt's Tools For The Job?

Yes..

A good explanation of just how
difficult cylinders were to make, and why the inability to make them
held up steam engine development for so long. For some years there was
only one foundry (John Wilkinson) that could cast a cylinder that was
acceptably cylindrical, and one boring engine that could machine them.
Watt's first commercially working engine (at Kinneil) had a cylinder
cast of block tin, rather than iron, because it was so difficult to make
usable iron cylinders.

All true - but by 1802 cylinder casting (and boring, which was the harder
part - early steam engine cylinders were fined to round by hand..) was
a much more mature technology (many of the improvements in casting and
boring, of course, having been driven by the more demanding specifications
for cannon..).
It's be fair to say that by 1800 high-quality iron casting of even large
cylinders was something that could be done by - at a rough guess -
10+ firms around the UK. Fabrication of large wrought-iron plate structures
was at a much earlier stage of development, though things were to change fast
in the next 10 years or so.

--
From the Model M of Andy Breen, speaking only for himself

On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

On Jul 16, 10:24*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! *Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would

Que ?

operate the valves manually. A big advance
was automatic operation.

Don't you know anything?

On Sun, 17 Jul 2011 16:23:44 +0100, Charles Ellson wrote:

On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27Â*pm, Andy Dingley wrote:
On Jul 16, 7:07Â*pm, harry wrote:

On Jul 16, 10:24Â*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on
vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! Â*Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

That's really nitpicking on the terminology. Displacing something by
admitting another fluid (or gas, or vapour) is often referred to as
"flushing"..

When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would

Que ?

There were various methods of operating valves automatically from a
fairly early stage, but most of them seem to have required coughing
up patent royalties. Provided someone cheap (or free..) could be
found to operate the valves manually, that was often a better deal
for the owner of the engine. A typical arrangement seems to have been
for the child of someone working elsewhere in the operation to to
the job, either for a /very/ small wage or as part of their father's
employment terms.
One such childhood valve-operator was George Stephenson.

By the early 1800s operation via strikers (pins on the rods of the engine
flipping the valve across) seems to have become the normal method of
operation, though presumably a few manually-operated engines would still
remain. In the locomotive context, valves operated by strikers can be
seen on the two surviving Wylam machines - and in operation on the
replica at Beamish:

http://www.youtube.com/watch?v=v_MLpJQswF4

Note that the valves would always need to be worked manually to start the
engine or after reversing it. This could be difficult, particulary on
a locomotive at night (Jem Stephenson was said to be the only man
who could reverse 'Locomotion' on his own at night, though Mike Satow
reckoned he could do it with the replica)

operate the valves manually. A big advance was automatic operation.


--
From the Model M of Andy Breen, speaking only for himself

On Jul 17, 10:18*am, geoff wrote:
In message
,
harry writes





On Jul 16, 11:03*pm, Charles Ellson
wrote:
On Sat, 16 Jul 2011 22:40:07 +0100, The Natural Philosopher

wrote:
Graeme Wall wrote:
On 16/07/2011 10:24, Guy Gorton wrote:
That seems very low. *My facts may be wrong but I think 30ft of water
creates 1 atmosphere of pressure, which is about 14 lbs/sq.in.

If I remember my schoolboy physics, it's 32ft of water and 15lbs/sq..in.

32.2 & 14.4 rings a bell..

14.7 rings it better unless you're somewhere up a mountain.

NPT = 1013 millibars at sea level. * We've gone metric, haven't you
heard?

It was supposed to be 1000mb but Napoleon's scientists got it wrong.

Not french by any chance, are you harry?

--
geoff- Hide quoted text -

- Show quoted text -

I used to fly. 1013 is the pressure you set your altimeter at away
from airfields so it is ingrained into the brain.
This is so everyone is flying at altitudes from the same basis.

On Jul 17, 4:23*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

On Jul 16, 10:24*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! *Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would

Que ?



operate the valves manually. A big advance
was automatic operation.

Don't you know anything?- Hide quoted text -

- Show quoted text -

So where exactly is the diffence?

On Sat, 16 Jul 2011 20:04:31 +0000, Andy Breen wrote:

On Sat, 16 Jul 2011 20:49:23 +0100, Clive wrote:

In message , Andy Breen
writes
The pet-cock,
Any similarity between this and the modern clack valve?

As I understand it, the pet-cock was for bleeding steam off from the
pump: "by opening (the pet-cock) the steam in the pump was let out, and
the action renewed" (Marshall, again).

I'd not expect a direct similiarity to anything on a "modern" steam
engine, as even the ones that use hot feed and pumps have the pump well
away from the boiler (and seals are much better, anyway)

Thinking some more...

The clack valve is - essentially - a non-return valve to stop boiler steam
getting back into the feed system, nyet? Presumably the pumps used in early
locomotives had non-return valves in them (well, they must have, being
intended to push water one way...), but it's clear from Marshall's comments
("hot water entered from the leaking of the valves, causing them (the pumps)
to be filled with steam") that they didn't work well enough to keep the
pumps at their duty. Given the materials available at the time, it's
easy to see how this happened - and given that until then most applications
requiring continuous working[1] had been the domain of low-pressure engines,
with Trevithick-type[2] high-pressure engines restricted to more intermittent
tasks[3] where the boiler could be topped up after each burst of work
(pressure having dropped then, anyway..), it's easy to see how the problem
hadn't been encountered before. The valves had worked well enough for low-
pressure (and stationary!) boilers, after all (actually, the battering
taken by the machinery in an unsprung locomotive on short - 3'-4' rails -
can't have helped the functioning of the pump valves at all!).

Essentially, if they could have made a really good clack valve, they'd
not have had the problem with the pumps locking and the pet-cock wouldn't
have been needed. As materials available meant they couldn't, the pet-cock
was a real breakthrough in producing a locomotive which could run more than
a very short distance between extended (and madly hazardous!) stops.

--
From the Model M of Andy Breen, speaking only for himself

On Sun, 17 Jul 2011 08:48:47 -0700 (PDT), harry
wrote:

On Jul 17, 4:23*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

On Jul 16, 10:24*am, Guy Gorton wrote:
No that is correct. They had huge pistons and very long strokes.

Early steam engines actually ran on vacuum.http://en.wikipedia.org/wiki/Atmospheric_engine

FFS! *Don't believe _anything_ on Wikipedia!

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

When it was
condensed (By a water jet) the piston was"sucked down"by the resultant
vacuum.
Hence "atmospheric."

So some a litte boy would

Que ?



operate the valves manually. A big advance
was automatic operation.

Don't you know anything?- Hide quoted text -

- Show quoted text -

So where exactly is the diffence?

"Flushing" is generally the deliberate rather than consequential
purging of a substance from somewhere. If you are referring to the
animation at the top of the above Wonkypaedia article then no such
process is shown but if any does take place then it will (except at
startup) be "expired" steam that is flushed rather than air.

On Sun, 17 Jul 2011 17:15:30 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 08:48:47 -0700 (PDT), harry
wrote:

On Jul 17, 4:23Â*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27Â*pm, Andy Dingley wrote:
On Jul 16, 7:07Â*pm, harry wrote:

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

So where exactly is the diffence?

"Flushing" is generally the deliberate rather than consequential purging
of a substance from somewhere. If you are referring to the animation at
the top of the above Wonkypaedia article then no such process is shown
but if any does take place then it will (except at startup) be "expired"
steam that is flushed rather than air.

Opening a valve to admit steam to the cylinder seems deliberate
enough to me.

It's fairly clear from his own writings that Mr Savery was of the same
opinion:

"Then skrew in the faid pipes again as tight as possible. Then lightthe
fire at B No.1. When the water in L boyles, the handle of the regulator
mark'd Z, must be thrust from you as far as it will go, which makes all
the steam rifting from the water in L, pass with irriftible force through
O No.1 into P No.1 pushing out all the air before it, through the clack
R No.1 making a noise as it goes."

'The Miner's Friend, or, An Engine To Raise Water By Fire', Thomas
Savery, S. Crouch, 1702, available on-line at:

http://library.thinkquest.org/C00601...am%2Fsavery%2F

To me, that implies a very deliberate use of the steam to flush out the
air in the working vessel..

--
From the Model M of Andy Breen, speaking only for himself

On Sun, 17 Jul 2011 16:25:57 +0000 (UTC), Andy Breen
wrote:

On Sun, 17 Jul 2011 17:15:30 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 08:48:47 -0700 (PDT), harry
wrote:

On Jul 17, 4:23*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27*pm, Andy Dingley wrote:
On Jul 16, 7:07*pm, harry wrote:

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the cylinder.
Get your intentions and consequences in the right order.

So where exactly is the diffence?

"Flushing" is generally the deliberate rather than consequential purging
of a substance from somewhere. If you are referring to the animation at
the top of the above Wonkypaedia article then no such process is shown
but if any does take place then it will (except at startup) be "expired"
steam that is flushed rather than air.

Opening a valve to admit steam to the cylinder seems deliberate
enough to me.

It's fairly clear from his own writings that Mr Savery was of the same
opinion:

"Then skrew in the faid pipes again as tight as possible. Then lightthe
fire at B No.1. When the water in L boyles, the handle of the regulator
mark'd Z, must be thrust from you as far as it will go, which makes all
the steam rifting from the water in L, pass with irriftible force through
O No.1 into P No.1 pushing out all the air before it, through the clack
R No.1 making a noise as it goes."

'The Miner's Friend, or, An Engine To Raise Water By Fire', Thomas
Savery, S. Crouch, 1702, available on-line at:

http://library.thinkquest.org/C00601...am%2Fsavery%2F

To me, that implies a very deliberate use of the steam to flush out the
air in the working vessel..

That device looks distinctly different to the one in the Wikipaedia
article. Rather than using a piston it seems to use alternative
positive and negative pressure (relative to atmosphere) in a vessel
with valves arranged so that water is sucked in from below then
discharged up to the surface. As often occurs, older descriptions can
be somewhat simplistic; the purpose is clearly to propel water while
any propulsion of air is consequential to some being present but not
necessary for the ongoing process.

On Sun, 17 Jul 2011 17:49:27 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 16:25:57 +0000 (UTC), Andy Breen
wrote:

On Sun, 17 Jul 2011 17:15:30 +0100, Charles Ellson wrote:

On Sun, 17 Jul 2011 08:48:47 -0700 (PDT), harry
wrote:

On Jul 17, 4:23Â*pm, Charles Ellson wrote:
On Sat, 16 Jul 2011 23:28:13 -0700 (PDT), harry
wrote:

On Jul 16, 9:27Â*pm, Andy Dingley wrote:
On Jul 16, 7:07Â*pm, harry wrote:

The staem was used to flush air out of the cylinders.

Er no, the air was displaced by the steam being fed into the
cylinder. Get your intentions and consequences in the right order.

So where exactly is the diffence?

"Flushing" is generally the deliberate rather than consequential
purging of a substance from somewhere. If you are referring to the
animation at the top of the above Wonkypaedia article then no such
process is shown but if any does take place then it will (except at
startup) be "expired" steam that is flushed rather than air.

Opening a valve to admit steam to the cylinder seems deliberate enough
to me.

It's fairly clear from his own writings that Mr Savery was of the same
opinion:

"Then skrew in the faid pipes again as tight as possible. Then lightthe
fire at B No.1. When the water in L boyles, the handle of the regulator
mark'd Z, must be thrust from you as far as it will go, which makes all
the steam rifting from the water in L, pass with irriftible force
through O No.1 into P No.1 pushing out all the air before it, through
the clack R No.1 making a noise as it goes."

'The Miner's Friend, or, An Engine To Raise Water By Fire', Thomas
Savery, S. Crouch, 1702, available on-line at:

http://library.thinkquest.org/C00601...am%2Fsavery%2F

To me, that implies a very deliberate use of the steam to flush out the
air in the working vessel..

That device looks distinctly different to the one in the Wikipaedia
article.

What? Counting on Wikipedia as an authority here?

Rather than using a piston it seems to use alternative positive
and negative pressure (relative to atmosphere) in a vessel with valves
arranged so that water is sucked in from below then discharged up to the

Yes. Newcomen's engine was essentially a combination of ideas from
Papin (piston-in-cylinder) and Savery (use of condensation of steam
to create a vacuum to raise water). The working principles, in
terms of the use of steam to expel the air from the working vessel
and then condensation to provide the working force, however, were
the same as Newcomen's machine - a fact recognised by Newcomen
himself, as he conceded that his machine was covered by Savery's
patent (the small number of Newcomen engines installed before
the expiry of Savery's patent was a result of this - the patent
royalties made them even more expensive).

surface. As often occurs, older descriptions can be somewhat simplistic;
the purpose is clearly to propel water while any propulsion of air is
consequential to some being present but not necessary for the ongoing
process.

The text clearly shows that Savery understood that his engine worked
by replacing the air in the working vessel with steam which could then
be condensed to create a vacuum, with the latter being used to raise
water (exactly the same principle as was adopted to a cylinder/piston
and separate boiler by Newcomen).

Maintaining otherwise shows a disregard for primary evidence which
surprises me in your case (I'd expect it from Michael, or Bruce
in recent years, but not you).

--
From the Model M of Andy Breen, speaking only for himself

In message , Andy Breen
writes
(I'd expect it from Michael, or Bruce
Not "Thee" Michael Baldwin Bruce of Monty Python fame?
--
Clive

On Sun, 17 Jul 2011 18:12:46 +0100, Clive wrote:

In message , Andy Breen
writes
(I'd expect it from Michael, or Bruce
Not "Thee" Michael Baldwin Bruce of Monty Python fame?

I'd not thought of that..

Rn away! Run away!

--
From the Model M of Andy Breen, speaking only for himself

On 16/07/2011 13:09, Andy Breen wrote:

Use of vacuum as an important part of the working cycle wasn't banished by
Trevithick either: his most effective and longest-lasting engine type, the
Cornish mine engine, used high-pressure steam on one side of the piston and
vacuum on the other - made it a very efficient power source for its
day.


It's lasted a bit longer than that.

You know those big cooling towers on power stations? The turbine
exhaust is into a partial vacuum...

Andy

On 16/07/2011 12:34, Clive wrote:
Very low pressures are entirely feasible considering that the steam was
only used to raise a piston which through a beam allowed what it was
working on (Man engine etc.) To drop, the steam was the condensed by
spraying in cold water and the atmospheric pressure on the other side of
the piston did the work.

Lower than you think. The beam was usually raised just by the weight of
the pump on the other end; the purpose of the steam was just to push
the air out. Then the condensation led to a partial vacuum, and the air
pressure does all the real work.

You guys really must go to Crofton Beam Engines. When they are in
steam, of course!

http://www.croftonbeamengines.org

Andy

On Sun, 17 Jul 2011 18:12:46 +0100, Clive wrote:

In message , Andy Breen
writes
(I'd expect it from Michael, or Bruce
Not "Thee" Michael Baldwin Bruce of Monty Python fame?


In uk.r the one to really be worried about would be Michael
Roland Bruce.

--
From the Model M of Andy Breen, speaking only for himself