On Tue 01 Aug, Brian Malaws wrote:
> Dear Group,
>
> I am informed that the Emlyn Brickworks, near Llanelli, has a Manchester Kiln. It app
> ears to be similar to a Hoffmann kiln, but how exactly does it differ? Can anyone enli
> ghten me please?
A Manchester kiln is a version of the Hoffmann kiln and is described in
"Heavy Clay Technology" by F H Clews, published by The British Ceramic
Research Association, Stoke-on-Trent 1955, pp208-209.
"The kiln ilustrated can be considered as divided into 16 chambers bythe
drop arches and wickets, although actual division walls are lacking. The
dimensions given are indicative only. The tunnel in which the bricks are set
measures about 8.5 ft high by 13.5 ft wide, with a total length of 230ft.
The main flue, which is about 4.25ft high by 4.25ft wide, can be seen in the
section AA and BB. It runs beneath the centre division wall, and
communicates with each chamber via a flue 2.25ft high by 1.5 ft wide under a
chamber and a downtake which can be opened or closed as required, by means
of a horizontal sliding metal damper plate on the outside of the side walls.
In the crown of the kiln there are 16 feed-holes to each straight chamber
and 19 to the four end chambers. They are about 5 in. in diameter and are
fitted with a recessed cap.
The kiln illustrated........, however, has another feature that was not in
the original Hoffman design, namely, a flue for withdrawing hot air, not for
combustion, but for drying. This type of kiln is used more for bricks made
by thestiff-plastic and semi-dry processes, for which the kiln also acts as
the dryer. The hot-air flue, which is 3 ft high by 2ft wide, is situated
above the centre dividing wall and has damper-controlled connections to
thetops of the chambers, as shown in section BB, and can be drawn off from
the tops of the cooling chambers and used for drying freshly-set chambers
until the danger ofmoisture containing sulphurous and sulphuric acids
condensing on the bricks is past. The arrangement has no thermal advantage
over the simpler original plan of Hoffmann but does help to avoid
discolorations that may result from the contact of cool bricks with moist
flue gases when the sulphur content of the fuel or clay is not negligible"
This description requires the diagram to make it more intelligible and I
will happily email a copy of this if you wish.
Cheers,
--
fearrmeox adlap braegen
)| David Kitching _____|______|_ ____
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