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'[TECH]:: Archimedes Screw - wide range of modern u'
2010\07\08@063929 by RussellMc

face picon face
Found this page while looking for something quite different (as often
happens)
Liable to be of at least passing interest to many.
Possibly even of unexpected practical use to some.


http://www.cs.drexel.edu/~crorres/Archimedes/Screw/Applications.html

I'm well aware of Archimedes Screw BUT had thought that it was relegated to
the roles of developing country water lifting (often manual), novelty toy
and garden ornament. Apparently not.
Largest listed above is 12 foot in diameter.
It's in Texas :-).

The page shows some quite modern implementations on an extremely large
scale.

Links to the following and more on the above page.
Some good photos.

Beer pump

Blood pump

*Water:*

Memphis (USA, not Egypt).
7 screws.
Each screw 96 inches / 8 feet / 2.5 metre  DIAMETER
20,000 gallons per minute !!!!!

Netherlands.
3 diesel driven screws, 1.35millions litres / minute !!!!!!!!!!!!
Built 1972.

Texas City, Texas.
Always bigger :-)
8 x 12 foot diameter screws.
125,000 gallons/minute (per screw?)

Sea World California.
Shipwreck Rapids adventure ride.
2 large screws.

2010\07\08@072316 by Alan B Pearce

face picon face
> Found this page while looking for something quite different (as often
> happens)
> Liable to be of at least passing interest to many.
> Possibly even of unexpected practical use to some.
>
>
> http://www.cs.drexel.edu/~crorres/Archimedes/Screw/Applications.html

They are being used for power generation in the UK, a reverse use to
what they are normally put to.

e.g. www.westernrenew.co.uk/Archimedes%20screw%20turbines.html
http://news.bbc.co.uk/1/hi/england/cornwall/7586285.stm

Also referenced here under 'turbine types' ...
http://en.wikipedia.org/wiki/Micro_hydro

--
Scanned by iCritical.

2010\07\08@081254 by Olin Lathrop

face picon face
RussellMc wrote:
> I'm well aware of Archimedes Screw BUT had thought that it was
> relegated to the roles of developing country water lifting (often
> manual), novelty toy and garden ornament. Apparently not.
> Largest listed above is 12 foot in diameter.
> It's in Texas :-).

One of the cool things about the Archimedes Screw is that it works both ways
with pretty much equal efficiency (which is quite high).

A long time ago I mentally designed a heat engine loosely based on the
concept of this screw.  It had exactly one rigid part and some fluid.  The
single rigid part rotates when you make one end hotter than the other.  Of
course a working version needs external parts to hold the single rotating
part in place, let it rotate, remove power from it, apply heat to one end,
cool to the other, etc.  But the engine itself is still just the one single
rigid part plus a fluid.  The fluid is sealed in.

I have never written this down before or made a drawing.  I did once try to
explain it to someone else, but I think they didn't get it.  If I remember
right, I had this idea in the mid 1990s.  I supposed I could write a SLIDE
program to draw a 3D model of it, but so far I haven't.

Anyone care to come up with this concept themselves?  If so, a brief
discussion of efficiency would be interesting.  After thinking about it for
a while, the losses, limitations, and how to overcome them were a little
surprising to me.


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2010\07\08@083412 by Carl Denk

flavicon
face
The archimedes screw is used very commonly to raise large volumes of
water a short distance, say less than 50' feet. 2 uses are, to raise
storm water flow over a level, or to a higher body of water, and in
water (both storm and sanitary) treatment plants, to raise incoming
water (including sanitary or industrial wastes) so that the remain
process can be by gravity flow. They are very low maintenance, 2
bearings to lube, a gearbox and motor that receives a no shock, uniform
load.

On 7/8/2010 8:13 AM, Olin Lathrop wrote:
{Quote hidden}

2010\07\08@095119 by Alan B Pearce

face picon face
> One of the cool things about the Archimedes Screw is that it works
both ways
> with pretty much equal efficiency (which is quite high).

Yeah, when I first heard of the generating systems (as per the links I
sent earlier) my intuition was that the water energy to electricity out
efficiency wouldn't be very high, but apparently it is worth the effort.

I had always thought of the Archimedes screw as being quite low
efficiency, but when used in a primitive society to raise water, it was
a case of something simple and effective, easy to make to what you had
around, without considering the efficiency.
--
Scanned by iCritical.

2010\07\08@101334 by Olin Lathrop

face picon face
alan.b.pearce@stfc.ac.uk wrote:
> Yeah, when I first heard of the generating systems (as per the links I
> sent earlier) my intuition was that the water energy to electricity
> out efficiency wouldn't be very high, but apparently it is worth the
> effort.
>
> I had always thought of the Archimedes screw as being quite low
> efficiency, but when used in a primitive society to raise water, it
> was a case of something simple and effective, easy to make to what
> you had around, without considering the efficiency.

Think about the losses of a simple screw used to raise water.  If it turns
slowly enough, there is very little friction loss between the water and the
screw.  Mechanical losses are just the bearings and drive mechanism, which
isn't much.  The main trickiness is to make sure the water at the output
(high) end is released as close as possible at the same height as the output
reservoir.  You have to think about this, but it can be achieved pretty
closely.  All in all, a quite efficient system can be made that is even
reversible.

I think the real problem with Archimedes screws is not the efficiency, but
the relatively low power or flow for their size.  A turbine using similar
amount of material can handle a much larger flow, and is also reasonable
efficient, at least at a chosen flow and power.

So anyone come up with a one-piece heat engine yet?  Temperature difference
in, rotary motion out.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\08@112518 by RussellMc

face picon face
> So anyone come up with a one-piece heat engine yet?  Temperature difference
> in, rotary motion out.

Just to start the ball rolling ...

Angled screw with top/high end and bottom/low end.
Thermosyphon loop with heat introduced at bottom of screw and cooling
at top of screw.
Fluid rises through screw turning it and cooling.
Rotation of screw against a load will cool the fluid fwiw - but this
drop willo be small compared to the delta-T needed for thermosyphon
operation.

Fluid is recirculated - probably though a counterflow heat exchanger
for efficiency.
How unused heat energy is reintroduced to hot end is TBD/exercise for student.
May best use a thermal wheel (agh!).
Continuous flow nature of the beast makes a regenerator hard.
Efficiency may not matter if this uses otherwise watse heat.
Upper efficiency ( use Z ) is limited by Carnot considerations so is
low to very low in most waste heat recovery situations.
ie  Z_Carnot = (Th-Tc)/Th or Tdelta/Thot.
For eg 10 degree C drop at room temperature (about 300K) that's about
10/300 ~= 3%.
Actual efficiency would be far below Carnot. In a well optimised heat
engine (eh high temperature, high pressure Stiling with Hydrogen
working fluid) Zactual/ZCarnot can get over 50% but that takes much
effort.

        Russell McMahon

2010\07\08@125343 by Michael Rigby-Jones

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face


> -----Original Message-----
> From: spam_OUTpiclist-bouncesTakeThisOuTspammit.edu [.....piclist-bouncesKILLspamspam@spam@mit.edu] On
Behalf
> Of Olin Lathrop
> Sent: 08 July 2010 15:14
> To: Microcontroller discussion list - Public.
> Subject: Re: [TECH]:: Archimedes Screw - wide range of modern uses
>
>
> So anyone come up with a one-piece heat engine yet?  Temperature
> difference in, rotary motion out.

Does the Crookes radiometer count?

Mike

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2010\07\08@131956 by Olin Lathrop

face picon face
RussellMc wrote:
>> So anyone come up with a one-piece heat engine yet? Temperature
>> difference in, rotary motion out.
>
> Just to start the ball rolling ...

I guess Russell is the only taker.

> Angled screw with top/high end and bottom/low end.
> Thermosyphon loop with heat introduced at bottom of screw and cooling
> at top of screw.

Yes, that was my idea also.

> Fluid rises through screw turning it and cooling.
> Rotation of screw against a load will cool the fluid fwiw - but this
> drop willo be small compared to the delta-T needed for thermosyphon
> operation.

Similar, but I think my idea would be more effective.

The trick is to make the fluid undergo a phase change between gas and
liquid.  Nothing else occupies the space inside the screw but this substance
in either its gas or liquid phase.  A pool of liquid collects at the bottom.
Heating it causes gas to boil off, which travels up the tube to condense at
the top (cold) end.  Since it is now liquid, it drives the Archimedes screw
in reverse on the way down.  Note that the scew is open, not like many
Archimedes screws which are coiled closed pipes.  The inside of the tube
looks more like the inside of a threaded nut.  Of course the circular grove
shape is optimized for holding liquid on the way down.

Efficiency is not that great, but it does work with low temperature
differences.  Just a few degrees difference between bottom and top will
cause liquid to condense at top, which will drive the screw as it falls back
to the bottom.

The reason efficiency sucks is because pretty much the same
temperature/pressure gas leaves the bottom as condenses at top.  The only
difference is due to the pressure difference from top to bottom due to
gravity.  To make it more efficient, you need a denser gas, longer tube, or
higher gravity.

Of course although the screw is open, there will be some insulation between
it and the center of the tube where the gas travels upwards.  Some gas will
condense part way up and drive the screw down from there, but for best
efficiency you want it to condense at the top.


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Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\08@132123 by Olin Lathrop

face picon face
Michael Rigby-Jones wrote:
> Does the Crookes radiometer count?

Not at all what I had in mind, but I guess it has a single part that
rotates.  It would be rather difficult to get much power from such a device
though.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\08@134837 by jim

flavicon
face
Unless it could be scaled up.  Then it might be possible.
Jim

-----Original Message-----
From: piclist-bouncesspamKILLspammit.edu [.....piclist-bouncesKILLspamspam.....mit.edu] On Behalf Of
Olin Lathrop
Sent: Thursday, July 08, 2010 12:22 PM
To: Microcontroller discussion list - Public.
Subject: Re: [TECH]:: Archimedes Screw - wide range of modern uses

Michael Rigby-Jones wrote:
> Does the Crookes radiometer count?

Not at all what I had in mind, but I guess it has a single part that
rotates.  It would be rather difficult to get much power from such a device
though.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\08@143130 by RussellMc

face picon face
> > Does the Crookes radiometer count?

> Not at all what I had in mind, but I guess it has a single part that
> rotates.  It would be rather difficult to get much power from such a device
> though.

I wonder how efficient the conversion is or what percentage of energy
can be transmitted to the rotor. It would be easy to drive a micro
alternator from such a device. Or rather, to integrate the rotor and a
custom built alternator.  Direct solar converson :-).


            Russell

2010\07\08@150744 by Michael Watterson

face picon face
 On 08/07/2010 19:30, RussellMc wrote:
>>> Does the Crookes radiometer count?
>> Not at all what I had in mind, but I guess it has a single part that
>> rotates.  It would be rather difficult to get much power from such a device
>> though.
> I wonder how efficient the conversion is or what percentage of energy
> can be transmitted to the rotor. It would be easy to drive a micro
> alternator from such a device. Or rather, to integrate the rotor and a
> custom built alternator.  Direct solar converson :-).
>
>
>               Russell
>
A rotor around a shaft, (inverted screw). Fluid rises up it ..  cools at
top, outside of rotor is normal screw in outer casing and fluid falls
back down the outside screw.

Magnets in the single  moving part that has a screw on inner and outer
surface. coils in outer casing.

2010\07\08@204944 by Sean Breheny

face picon face
One thing which I do not understand is why the screw is better (as a
pump, not as a generator) than, say, a water wheel with buckets or
bucket-like scoops on it. Intuitively the wheel would seem better
because when held stationary, it does not allow back-flow. However, if
you stop the screw and hold it, water can flow backwards (at least
whatever water is in the screw at the time). This means that the screw
has zero efficiency up to a certain rotational speed (where the
pumping action counteracts the backflow).

Sean


On Thu, Jul 8, 2010 at 9:51 AM,  <EraseMEalan.b.pearcespam_OUTspamTakeThisOuTstfc.ac.uk> wrote:
{Quote hidden}

> -

2010\07\08@210320 by John Gardner

picon face
What backflow?   :)

Jack

2010\07\09@021738 by Sean Breheny

face picon face
I'm not sure if that's a joke or not. I realize that the water which
has fully reached the top will not backflow since it is lower than the
end of the screw. However, any water inside the screw will flow back
down into the lower pool if the screw speed is insufficient to keep up
with the pull of gravity on the water. Am I missing something?

On Thu, Jul 8, 2010 at 9:03 PM, John Gardner <goflo3spamspam_OUTgmail.com> wrote:
> What backflow?   :)
>
> Jack
>

2010\07\09@044201 by Alan B Pearce

face picon face
> I'm not sure if that's a joke or not. I realize that the water which
> has fully reached the top will not backflow since it is lower than the
> end of the screw. However, any water inside the screw will flow back
> down into the lower pool if the screw speed is insufficient to keep up
> with the pull of gravity on the water. Am I missing something?
>
> On Thu, Jul 8, 2010 at 9:03 PM, John Gardner <@spam@goflo3KILLspamspamgmail.com> wrote:
> > What backflow?   :)

It's not a joke, as for most of the screw the water does not cover the screw, so the water cannot backflow. If the screw is made as a channel with an open top (see the pictures in the links I posted previously about power generation using a screw) then the only backflow is when the water overflows a turn of the screw.

There will be a trickle backflow due to an inevitable gap between the screw and the channel, but careful design would make this reasonably minimal.
--
Scanned by iCritical.

2010\07\09@075513 by Sean Breheny

face picon face
Isn't the screw, when stopped, a continuous inclined plane so that
water poured in at one end would just run "downhill" around the turns
of the screw and out the other end? I did look at the photos and
that's what it appeared to me.

Sean


On Fri, Jul 9, 2010 at 4:30 AM,  <KILLspamalan.b.pearceKILLspamspamstfc.ac.uk> wrote:
{Quote hidden}

>

2010\07\09@080912 by RussellMc

face picon face
See  http://www.british-hydro.co.uk/download.pdf
<http://www.british-hydro.co.uk/download.pdf>for a 31 page mini hydro manual
(ref from Alan's link below).
Not overly technical, but some useful stuff.

Most use of all to storw in brain:

Rectangualr weir flow rate

Flow = 1.8 (L-0.2h). h^1.5

        Flow m^3/sec
        L = width in m
        h = water height over weir  in m

Translates into other units in expected manner.
Note this is a simplification of

Flow = 2/3 Cd sqrt(2g)(L-0.2h)h^1.5
See report for details.

Available power from hydro typically 60%-70% of gross available energy

= eg   kW = m^3/sec flow x m head x 6            (60% efficient)


      Russell





On 8 July 2010 23:23, <spamBeGonealan.b.pearcespamBeGonespamstfc.ac.uk> wrote:

{Quote hidden}

2010\07\09@082812 by Carl Denk

flavicon
face
Not, the ones I worked with (5 foot diameter, turning maybe a little
faster than 1 revolution per second), but there is significant leakage
between the screw and the tube. The working clearances for machinery
that big, and without getting into costly tight tolerances are loose,
maybe 1/2" or more between the screw and tube.

On 7/9/2010 7:55 AM, Sean Breheny wrote:
{Quote hidden}

>> --

2010\07\09@084542 by RussellMc

face picon face
--000e0cd2d91cd486f2048af3c788
Content-Type: text/plain; charset=ISO-8859-1
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            BCCs - especially see "Superb example" link below:

The Archnimedes screw pump (or hydraulic motor) does NOT usually
operate in the manner which may be intuitively assumed.

ie IF the screw had zero centre diameter then it would act as a pipe
with a spiral guide in it and water would flow down it when stopped.
BUT as the centre diameter is made an increased  fraction of the outer
diameter you form "buckets" at the bottom of each spiral loop. The
size of the buckets as a proportion of the total pipe internal volume
depends on both the inner/outer ration AND the tilt angle.

Look at the decorative screw pumps which consist of a spiral tube with
a large air space down the middle. It is very easy to visualise the
"buckets of water trapped in each loop. Attached GIF gives a good
visualisation and an excellent real world example is here.

SUPERB EXAMPLE :

       http://www.swansea.ac.uk/grst/images/Archimedes'%20screw.jpg

This allows the crucialrole of the OD/ID ratio to be seen.
Note that here the screw is formed on the outer wall so there is NO
leakage when static.
A screw with given ID/OD ratio can also be inserted in a tube, when
there will be leakage between the tube and screw.
For this design the outer wall height of the buckets becomes relevant
- for a screw in tube design the outer wall is continuous.

I guess that an eg Teflon coated version of the above shown screw
should be able to provide an extremely high efficiency.

As implemented here water is spilling from successive turns due to the
buckets being brim full, but an inlet scheme could be arranged to
slightly underfill each bucket initially. As seen here tilt angle and
ID/OD ratio are not optimised - as the buckets are spilling on the
outer edges but water level is not up to the ID edge. IE a slightly
steeper tilt would lose less water for this % of fill.

Note that this pump can operate across a wide speed range - and stop
without losing water. If manually operated this pump would allow
delivery rate to vary with user's input energy.

____________________

A screw with zero or "too small" ID/OD ratio can operate as a pressure
turbine that pumps dynamically BUT in most cases the system is
effectively operated so as to effectively be a series of buckets. ie
it is a positive displacement pump with gravity providing the cap to
the buckets.

A horizontal screw will still transport liquid with the maximum outlet
head being the height of the inner edge of the lower part  of the
spiral, and the input head minimum being level with the lower outer
edge.

Note that the various heat engine solutions being discussed in
response to Olin's challenge do NOT use the screw in the above
manner-they use it as a an inertial or momentum driven system with the
fluid flow reacting against the rotor. This would work conceptually
but is liable to have much of the flow bypass the screw - depending a
lot on design.



                   Russell McMahon




{Quote hidden}

screw, so the water cannot backflow. If the screw is made as a channel with=
an open top (see the pictures in the links I posted previously about power=
generation using a screw) then the only backflow is when the water overflo=
ws a turn of the screw.
> >
> > There will be a trickle backflow due to an inevitable gap between the s=
crew and the channel, but careful design would make this reasonably minimal=
.

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2010\07\09@085520 by Oli Glaser

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--------------------------------------------------
From: "Carl Denk" <cdenkEraseMEspam.....windstream.net>
Sent: Friday, July 09, 2010 1:28 PM
To: "Microcontroller discussion list - Public." <EraseMEpiclistspammit.edu>
Subject: Re: [TECH]:: Archimedes Screw - wide range of modern uses

{Quote hidden}

I think it would if the screw were vertical. When it is angled, the
"incline" is no longer "downhill", so it's like a line of "cups" in series
moving from one end to the other (the screw is less than half full).


2010\07\09@102924 by Carl Denk

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I have only seen inclined screws. This is far from my area of
engineering expertise, but my travels and work as a civil engineer has
brought me close to more than a few of these machines. When stopped, it
doesn't take long for all liquid to drain down to the bottom pool
elevation. The clearances I was talking of were compared to a turbine
aircraft engine, where the blade clearances are in thousands of an inch.
The tube does not become near total full of liquid, but maybe 1/4 full,
and the motion of the screw is fast enough to overcome the natural flow
of the liquid down, much like  a leaky bucket elevator.

The actual mechanics of this device is much more the realm of a fluid
dynamics specialist.

On 7/9/2010 8:53 AM, Oli Glaser wrote:
{Quote hidden}

2010\07\09@104238 by RussellMc

face picon face
> When stopped, it
> doesn't take long for all liquid to drain down to the bottom pool
> elevation. The clearances I was talking of were compared to a turbine
> aircraft engine, where the blade clearances are in thousands of an inch.
> The tube does not become near total full of liquid, but maybe 1/4 full,
> and the motion of the screw is fast enough to overcome the natural flow
> of the liquid down, much like  a leaky bucket elevator.

Note that the "screw binded to outer wall" version does not leak at
all when stationary. It will retain all fluid and restart immediately
where it left off when restarted (with suitable allowances for reality
such as a bit of slop and surge).


SUPERB EXAMPLE :

      http://www.swansea.ac.uk/grst/images/Archimedes'%20screw.jpg



      Russell

2010\07\09@105312 by Carl Denk

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Very good picture. With the spiral of sheet metal instead of a solid
cylinder, you can really see what's happening. Though there are some
units that the tube is fixed, and the screw only rotates.

On 7/9/2010 10:42 AM, RussellMc wrote:
{Quote hidden}

2010\07\09@110528 by Sean Breheny

face picon face
OK, I think the point I didn't understand is that the shaft angle
can't be so steep that the water ever "sees" a downhill path which is
backwards along the screw. I don't know why it is but I have such
trouble visualizing rotating things - even the photo wasn't enough for
me, I had to take a paper cup and draw a spiral on it, mark some
points, and then rotate it. What did it for me was to follow what
happens to one "bunch" of water as it goes through. If you look at
each point in time and find the local minimum of height for that bunch
of water and call it point A, then when you animate the motion, point
A is always moving up even though any point which you pick that is
fixed to the screw has no net upward motion but only an up and then
down cycle.

Sean


On Fri, Jul 9, 2010 at 10:42 AM, RussellMc <RemoveMEapptechnzTakeThisOuTspamspamgmail.com> wrote:
{Quote hidden}

>

2010\07\09@181139 by Olin Lathrop
face picon face
John Gardner wrote:
> What backflow?   :)

We'll never know since you didn't provide any context to your question.

Once again, QUOTE the relevant parts of what you are replying to and TRIM
the rest.  Why is this hard to understand!?


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2010\07\09@182215 by Olin Lathrop

face picon face
Sean Breheny wrote:
> Isn't the screw, when stopped, a continuous inclined plane so that
> water poured in at one end would just run "downhill" around the turns
> of the screw and out the other end?

No.  Go get the biggest nut for a machine screw you can get your hands on
easily.  Dunk it in water and pull it out such that the screw axis is
horizontal.  Now look at the threads inside and note how water is trapped in
each thread separately at the bottom.  Now rotate the nut and you can see
the trapped puddles of water stay at the bottom but move along the screw
axis.  In fact, they are acting like the screw inside the nut.

Now you can tilt the nut so that one end of the screw axis is a little
higher than the other.  Some water is still trapped in each thread, although
a little less.  By rotating the nut, you can now "pump" water up hill by
turning it one way and downhill by turning it the other way.  If you tilt
the nut all the way so that the screw axis is vertical, it no longer holds
any water.

Archemedes spirals use this principal, with the thread shape specifically
designed to hold liquid.  Their tilt is usually around 45 degrees.  That may
be too much for the nut since its thread shape was designed to mate with a
machine screw, not to hold water.


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(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\09@182653 by Olin Lathrop

face picon face
RussellMc wrote:
> Note that the various heat engine solutions being discussed in
> response to Olin's challenge do NOT use the screw in the above
> manner-they use it as a an inertial or momentum driven system with the
> fluid flow reacting against the rotor.

No, mine certainly uses it in the traditional Archemedes spiral mode.  My
design does not rely on any inertia.  If you were to externally hold my heat
pump fixed for a little while, it would actually store up some internal
potential energy such that you'd get more out when you released it.


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(978) 742-9014.  Gold level PIC consultants since 2000.

2010\07\22@031618 by Moreira, Luis A

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face
Hi,
I always wandered about clearances, how close coupled do you guys think
is the screw to the wall of the tube?
As anyone found any design notes on designing and building one/
Best Regards
            Luis

{Original Message removed}

2010\07\22@052659 by RussellMc

face picon face
Luis said:
> I always wandered about clearances, how close coupled do you guys think
> is the screw to the wall of the tube?
> As anyone found any design notes on designing and building one/

Note the two variants described.

1. Screw turns in tube.

2. Tube with spiral on outer wall is turned.

[image: archimedes1.gif]

3. Spiral wound tube.

     http://www.swansea.ac.uk/grst/images/Archimedes'%20screw.jpg

Call 1 Type A.
Call 2 & 3 type B as they are essentially the same in sub-principle.

All 3 work the same way in principle BUT type B  & 3 has zero leakage and
zero clearance issues. Screws of this type could pump fluid at a variable
rate including fully stopped without loss of fluid. It would be interesting
to know how many currently in use designs use this version.

Type 3 seems potentially somewhat harder than type 1 and there are some
mechanical / drive differences but it does not seem to have a 1st order
material cost penalty. ie there may be some differences in details re
costing but at first glance it seems that a competently built version of
either would use about the same materials AND be leak free at any speed.

You could easily enough derive a material requirement formula for the 3
types.

Thought - I've never seen this done but it's sure to exist. If you had a
series of "buckets" on a rotating shaft they could have outlets arranged to
empty into a "higher bucket"on rotation. Effect would be same as an AS but
more spectacular. Extra losses would occur from pouring and impact (heating)
losses but there would be less flow losses.



   Russell McMahon

2010\07\22@083638 by Carl Denk

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face
On the say 6' diameter, might be 1/2" or more. THese are not made to
aircraft engine tolerances, more like a structural steel fabricating
shop, and that screw is somewhat difficult to shape and weld together
with any real precision. Usually there is no machining of the screw O.D.

On 7/22/2010 3:16 AM, Moreira, Luis A wrote:
> Hi,
> I always wandered about clearances, how close coupled do you guys think
> is the screw to the wall of the tube?
> As anyone found any design notes on designing and building one/
> Best Regards
>               Luis
>
> {Original Message removed}

2010\07\22@084550 by RussellMc

face picon face
Luis:
>> I always wandered about clearances, how close coupled do you guys think
>> is the screw to the wall of the tube?
>> As anyone found any design notes on designing and building one/

Carl:
> On the say 6' diameter, might be 1/2" or more. THese are not made to
> aircraft engine tolerances, more like a structural steel fabricating
> shop, and that screw is somewhat difficult to shape and weld together
> with any real precision. Usually there is no machining of the screw O.D.

To start off one MAY be better off winding some sort of tubing around
a centre core.
Result will be a guaranteed leak proof pump at any angle less than
vertical. Volume pumped per turn is related to tube diameter, core
diameter and angle.

Simple to play would be garden hose.

Easy to make but more robust would be eg copper tube - possibly anneal
before bending.

Impressive would be exhaust tubing.

I can imagine a multi section design using injection moulded segments
joined together to make whatever length is required.

I sense a Coke can based design aborning.


           Russell

2010\07\22@084550 by RussellMc

face picon face
Luis:
>> I always wandered about clearances, how close coupled do you guys think
>> is the screw to the wall of the tube?
>> As anyone found any design notes on designing and building one/

Carl:
> On the say 6' diameter, might be 1/2" or more. THese are not made to
> aircraft engine tolerances, more like a structural steel fabricating
> shop, and that screw is somewhat difficult to shape and weld together
> with any real precision. Usually there is no machining of the screw O.D.

To start off one MAY be better off winding some sort of tubing around
a centre core.
Result will be a guaranteed leak proof pump at any angle less than
vertical. Volume pumped per turn is related to tube diameter, core
diameter and angle.

Simple to play would be garden hose.

Easy to make but more robust would be eg copper tube - possibly anneal
before bending.

Impressive would be exhaust tubing.

I can imagine a multi section design using injection moulded segments
joined together to make whatever length is required.

I sense a Coke can based design aborning.


           Russell

2010\07\25@052133 by William \Chops\ Westfield

face picon face

On Jul 22, 2010, at 5:45 AM, RussellMc wrote:

> I sense a Coke can based design aborning.

I was thinking 2l Bottles...

BillW

2010\07\25@184339 by RussellMc

face picon face
>> I sense a Coke can based design aborning.
>
> I was thinking 2l Bottles...


               BCC:  Ken - water motors at end may be of practical interest.

Bottles could be good due to the shape and existing "nozzle".

Cut rectanglarish hole in side of bottle for preceding bottle to pour into.
Angle "lower" bottle so that when in correct position water leaving
the nozzle pours into "higher" bottle.
Exit hole can be made larger by trimming neck.
Exit hole can be angled to present an essentially circular profile in
the exit plane when the bottle is at best exit position.

Should work. Would be "mind boggling" to the uninitiated.

An Archimedes Screw can run backwards as a water motor - the bottle
design could be optimised to accept water into the top bottle from a
nozzle and to "pass it" down successive bottles. This becomes a true
potential energy water motor - such as a water wheel but allows a
small diameter wheel. Speed  for a given power level / flow rate would
be higher than a large diameter "single descent" wheel. MAY even be
practical.

This suggests that a coiled hose water motor may also be useful. Would
be easy to build a test version and MAY even be able to serve
practical purposes. Assuming stiction and friction losses can be kept
to a smallish proportion of power available it would run across a wide
range of power levels as water was available to drive it.

Such motors, or course, for a given efficiency level, can get no more
power from a water head than other turbine types BUT may be more
practical in some head & flow regions. Losses for a discrete bucket
"poured" system come from heat energy caused by kinetic energy
absorbtion (some KE gets used). A true screw system  water motor has
friction and turbulence losses. Would be interesting to see how
efficient a system could be derived.

A large diameter screw (hose pipe wound on drum of much larger
diameter than hose diameter) has a low operating speed per energy and
high torque and MAY be able to be used for eg practical gate openers
or similar. 100 litres falling 2 metres from eg a roof in a rain
shower have 2000 Watt-second of energy. Not very much as a continuous
energy source, but if 50% energy was extractable, that's eg 100 Watts
for 10 seconds. 100 Watts is 10 litre-metres per second - maybe a bit
high for sensible tubing based systems. 10 Watts for 100 seconds = 1
litre-metres per second which could be sensibly realised.



           Russel

2010\07\26@124252 by Marcel Birthelmer

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For those interested in water power and its use in industrial times in the
US, the book "Waterpower in Lowell, MA"  may be of interest. I bought it on
a whim, not having much knowledge or experience with water power, and I
found it a mostly interesting, if (ironically) mildly dry treatment of the
use of water power in revolutionizing industrial operations around that
time. It's not a highly technical treatise, but more of a historical
perspective

2010\07\26@131115 by Olin Lathrop

face picon face
Marcel Birthelmer wrote:
> For those interested in water power and its use in industrial times
> in the US, the book "Waterpower in Lowell, MA"  may be of interest. I
> bought it on a whim, not having much knowledge or experience with
> water power, and I found it a mostly interesting, if (ironically)
> mildly dry treatment of the use of water power in revolutionizing
> industrial operations around that time. It's not a highly technical
> treatise, but more of a historical perspective.

For anyone that might be interested in such things and find themselves in
the area, much of the water works and related infrastructure is now part of
the Lowell National Historic Park.  The canals are still largely intact.
One of the old industrial buildings, Wannalancit Mill, has been restored and
turned into a museum.  A bunch of years back I heard of plans to run the
turbine at Wannalancit Mill for real as a demonstration, but I don't know if
that ever happened.  There is also a museum in another area, with canal
tours available.  It's all rather well done, and worth a afternoon if you're
interested in such things.

Dave may chime in with more accurate and complete information.


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