IMPROVEMENTS IN THE MANUFACTURE OF CLAY RETORTS
Year: 1884

page_text: COMPLETE SPECIFICATION.
I WILLIAM DEWHIRST CLIFF of Wortley near Leeds in the county of York,
Retort, Fire brick aud Tube manufacturer do hereby declare the nature of my said
Invention for IMPROVEMENTS IN THE MANUFACTURE OF CLAY RETORTS, and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
The Invention consists in applying to the interior surfaces of retorts used for tho
distillation of coal and the production of gas previous to their being fired, that is
in the green or clay state-a body of a very close and fine nature, and a glaze in
connection therewith.
The composition or body of an ordinary clay retort is very porous and open, and
it is found in practice that the carbon readily attaches itself to the surfaces, so that
in course of time the internal dimensions of the retorts are seriously interfered with
and it becomes necessary to clean or scruf them.
In order to reduce or prevent this I face or line the inside surfaces of these
retorts with a distinct body of very fine close material of any of the descriptions
well known to potters such for example as a "porcelain body."
This is composed of materials the nature of which is well known to pottery
manufacturers, but as the contraction of the materials from which clay retorts aro
made, varies with each maker, this "porcelain body" will require slight alteration
to suit the particular clay mixture on which it has to be applied, as will be well
understood.
It is necessary that the retort be at the proper point of dryness when applying
the coating to ensure that the porcelain body shall firmly unite with and become
part and parcel of the body of the retort.
In those retorts which are built up by hand and which take from ten to twenty
one days from beginning to finishing, it is necessary to apply the porcelain body
from time to time as the retort progresses, but in those made by machinery the
application can be completed at one time.
Afterwards when the body has become sufficiently hard and set, I cover this
body with another inixture of any of the descriptions well known to potters which
when fired to the proper heat, fluxes and forms a glaze, thus producing an internal
ining to these retorts of a thoroughly vitreous nature, which will prevent tho
leposition of carbon and consequently allow at all times the full area of the retort
o be utilized.

page_text: I may say that I am aware that it has been the practice of some makers to brush
on their retorts a thin coating of fine ground bricks, clay and other material and
work it into the body of the retort, and with some advantage-the thin film thus
.produced doubtless doing some good, but according to my present invention I apply
a distinct and defined body different from any film produced by such process as has
been mentioned.
As all is done in the clay stato, it will be seen that the extra expense and risk
to the manufacturer is not great as by this process there is no second firing.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is,
Facing or lining the inside surfaces of clay retorts in their clay or green state
with a distinct body of very fine close material and with another mixture which
when fired produces a glazed surface all substantially as herein described, and for
the purpose stated.