Table Of ContentLime kiln, Willy Spahn
Park in Hannover
Lime kiln and chimney at
Llanymynech Heritage
Area, Shropshire photo:
John M, geograph.org.uk
Cross-section of ring
oven, Friedrich Eduard
Hoffmann's patent,
1858
Hoffmann kiln
From Wikipedia, the free encyclopedia
The Hoffmann kiln is a series of batch process kilns.
Hoffmann kilns are the most common kiln used in production
of bricks and some other ceramic products. Patented by
German Friedrich Hoffmann for brickmaking in 1858, it was
later used for lime-burning, and was known as the Hoffmann
continuous kiln.
Contents
◾ 1 Construction and operation
◾ 2 Historic examples of Hoffmann kilns
◾ 3 References
◾ 4 External links
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Construction and operation
A Hoffmann kiln consists of a main fire passage surrounded on each side by several small
rooms. Each room contains a pallet of bricks. In the main fire passage there is a fire wagon,
that holds a fire that burns continuously. Each room is fired for a specific time, until the
bricks are vitrified properly, and thereafter the fire wagon is rolled to the next room to be
fired.
Each room is connected to the next room by a passageway carrying hot gases from the fire.
In this way, the hottest gases are directed into the room that is currently being fired. Then the
gases pass into the adjacent room that is scheduled to be fired next. There the gases preheat
the brick. As the gases pass through the kiln circuit, they gradually cool as they transfer heat
to the brick as it is preheated and dried. This is essentially a counter-current heat exchanger,
which makes for a very efficient use of heat and fuel. This efficiency is a principal advantage
of the Hoffmann kiln, and is one of the reasons for its original development and continued
use throughout history.[1] In addition to the inner opening to the fire passage, each room also
has an outside door, through which recently fired brick is removed, and replaced with wet
brick to be dried and then fired in the next firing cycle.
In a classic Hoffmann kiln, the fire may burn continuously for years, even decades; in Iran,
there are kilns that are still active and have been working continuously for 35 years. Any fuel
may be used in a Hoffmann kiln, including gasoline, natural gas, heavy petroleum and wood
fuel. The dimensions of a typical Hoffmann kiln are completely variable, but in average
about 5 m (height) x 15 m (width) x 150 m (length).
Historic examples of Hoffmann kilns
The Hoffmann Kiln is used in almost every country. In the British Isles there are only a few
Hoffmann kilns remaining, some of which have been preserved. The only ones with a
chimney are at Prestongrange Industrial Heritage Museum and Llanymynech Heritage Area.
The site at Llanymynech, close to Oswestry was used for lime-burning and has recently been
partially restored as part of an industrial archaeology conservation project supported by
English Heritage and the Heritage Lottery Fund.[2] The Hoffmann lime-burning kiln at Meal
Bank Quarry, Ingleton is a scheduled ancient monument.[3]
There is an intact but abandoned Hoffmann kiln without a chimney present at Minera
Limeworks; the site is abandoned but all entrances to the kiln have been grated-off,
preventing access. The kiln is in a very poor state of repair, with trees growing out of the
walls and the roof. Minera Quarry Trust hopes one day to develop the area into something of
a tourist attraction. There is a partly preserved Hoffmann lime kiln that was operated by the
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Hoffmann ring oven in
Mildenberg museum
Kite aerial photo of a
Hoffmann brick kiln during
demolition in 2012,
Armadale, West Lothian.
Craven Lime Works company at Langcliffe in the Yorkshire Dales.[4][5] The Grade II listed
Hoffmann brick kiln in Ilkeston, Derbyshire, is also badly neglected, although the recently
installed fencing offers some protection for the building and for visitors.[6] At Prestongrange
Museum, outside Prestonpans in East Lothian, the Hoffman kiln is still standing and visitors
can listen to more about it via a mobile phone tour. There is also a nearly complete kiln in
Horeb, Carmarthenshire.[7] At the Brunswick brickworks in Victoria, Australia, there are two
surviving kilns converted to residences, and a chimney from a third kiln, another in Box Hill,
also in Melbourne and one in Adelaide, South Australia.[8] Also, two in New Zealand.
References
1. The History Channel, Modern Marvels, "Bricks", repeat: April
18, 2008 (http://www.history.com/minisites/modernmarvels)
Archived
(https://web.archive.org/web/20080416024356/http://www.history.com/minisites/modernmarvels)
April 16, 2008, at the Wayback Machine.
2. "Clwyd-Powys Archaeological Trust - Projects - Recent projects - Llanymynech". Cpat.org.uk.
Retrieved 2013-08-04.
3. Historic England. "Meal Bank Quarry Hoffmann kiln, quarry and lime works (1020889)".
National Heritage List for England. Retrieved 6 June 2015.
4. https://web.archive.org/web/20091126001740/http://www.langcliffe.net/Hoffmans%20Kiln.html.
Archived from the original on November 26, 2009. Retrieved September 6, 2009. Missing or
empty |title= (help)
5. "A landscape through time". Out of Oblivion. Retrieved 2013-08-04.
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Hoffmann kiln - Wikipedia
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Wikimedia
Commons has
media related to
Ring kilns.
6. Good Stuff IT Services. "Brick Kiln - Erewash - Derbyshire - England". British Listed Buildings.
Retrieved 2013-08-04.
7. http://www.britishlistedbuildings.co.uk/wa-20537-hoffmann-kiln-of-eclipse-brickworks-llane
8. Iain Stuart, Why Did the Hoffman Brick and Pottery Works Stop Making Bricks? Australian
Historical Archaeology 7, 1989 (http://www.ashadocs.org/aha/07/07_04_Stuart.pdf)
External links
◾ http://www.llanymynech-hoffman.co.uk/DIR1/History.htm
◾ http://www.prestongrange.org/tour/3.html
◾ http://www.itcltd.com/wastedisposal/1.1.4.d.Evaluation%20of%20Hoffman%20Kiln%
20Technology.pdf
◾ http://www.britishlistedbuildings.co.uk/en-352235-brick-kiln-ilkeston
◾ http://canmore.rcahms.gov.uk/en/site/151546/details/armadale+etna+brickworks/
RCAHMS Canmore
◾ http://au.news.yahoo.com/thewest/a/-/wa/18074142/laying-a-case-for-brickworks/
Retrieved from "https://en.wikipedia.org/w/index.php?
title=Hoffmann_kiln&oldid=749679906"
Categories: Industrial processes
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