Evening all,

While we're on the subject of mysterious old infrastructure-related
plaques on the sides of buildings:

http://urchin.earth.li/~twic/Duffield_Sluice.jpg

Any takers on what the Duffield Sluice is (or was)? Something to do with
the Surrey and Kent sewers, i suppose, but i wonder if anyone has any more
detailed ideas.

This sign is on a house near to the Thames in Bermondsey, facing the Old
Justice pub, roundabout he

http://maps.google.co.uk/maps?q=SE16...005,0.02&hl=en

tom

--
When I see a man on a bicycle I have hope for the human race. --
H. G. Wells

In message , Tom
Anderson writes

While we're on the subject of mysterious old infrastructure-related
plaques on the sides of buildings:

http://urchin.earth.li/~twic/Duffield_Sluice.jpg

Any takers on what the Duffield Sluice is (or was)? Something to do
with the Surrey and Kent sewers, i suppose, but i wonder if anyone has
any more detailed ideas.

Almost certainly it was originally a sluice gate for one of the many
tidal mills in Bermondsey. Ditches would channel the incoming Thames
tide into mill ponds and the sluice gate would be shut to trap the
water. During working hours, providing there was an outgoing tide, the
gate would be opened to allow the water back into the river, powering
various mills as it went.

From the description, it looks to be close to the point where the small
ditch enters the Thames, bottom right of the following:

http://users.bathspa.ac.uk/greenwood...8h.html#bottom

You can see "Mill Pond Street" close by, and if you click down (and
right) to the adjacent map segments, you can see the various large mill
ponds.

Many of these ditches (and the branches of the nearby Neckinger river)
were used as open sewers by the early 19th century.

I don't know who Duffield was - probably a local mill owner, but
possibly the John Duffied who built a pump room and spa at the head of
the Fleet, on Hampstead Heath, in 1701.

--
Paul Terry

"Paul Terry" wrote in message
...
In message , Tom
Anderson writes

http://urchin.earth.li/~twic/Duffield_Sluice.jpg

Almost certainly it was originally a sluice gate for one
of the many tidal mills in Bermondsey. Ditches would
channel the incoming Thames tide into mill ponds and
the sluice gate would be shut to trap the water. During
working hours, providing there was an outgoing tide, the
gate would be opened to allow the water back into the
river, powering various mills as it went.

I thought tidal mills operated both as the tide went in and when it went
out.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

In message , John Rowland
writes

I thought tidal mills operated both as the tide went in and when it went
out.

I think a few were reversible (the one built into London Bridge for
lifting water, for example) but most of those operating machinery worked
only on the outflow - I suspect because rather complicated mechanics
might well be necessary to make everything reversible (and by the time
engineering had reached that stage, steam was replacing water power).

There's a rather fun animation of the typical system (requiring Flash)
at:

http://home.freeuk.com/david.charter...ls/mymodel.htm

--
Paul Terry

JRS: In article , dated Wed, 23 Nov 2005
10:33:08, seen in news:uk.transport.london, Paul Terry
posted :
In message , John Rowland
writes

I thought tidal mills operated both as the tide went in and when it went
out.

I think a few were reversible (the one built into London Bridge for
lifting water, for example) but most of those operating machinery worked
only on the outflow - I suspect because rather complicated mechanics
might well be necessary to make everything reversible (and by the time
engineering had reached that stage, steam was replacing water power).


Not complicated, by not reversing the machinery.


Tidal River
---------------- ---------------
| ----------------- |
*==== Machinery ====*
| ----------------- |
---------------- ---------------
Pond


Each *==== is a lock gate, hinged at *; they're drawn in the neutral
position, but while working one is (on the diagram) up and the other is
down (they're always parallel).

If the left one is swung as the water will push it, and the right one is
swung the other way, water will always flow left-to-right through
Machinery.

Either you pay a man to move the gates at slack water; or you make the *
into pinions, engaging with worms driven by fan-wheels driven by flow
through a small pipe from river to pond - something like the fan-wheel
of a windmill which puts the main wheel facing the wind. The man would
be cheaper.

I have no idea whether anyone did it or thought of it; it's essentially
a hydraulic full-wave rectifier using switches for diodes.

--
© John Stockton, Surrey, UK. / ©
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