Year: 1886

page_text: I HENRY DOULTON of Lambeth in the County of Surrey Pottery Manufacturer
do hereby declare the nature of this invention to be as follows:-
This Invention has for its object an improvement in the process of making the
description of Pottery known as Bristol stone ware.
Bristol stoneware is the sort of pottery which has a glaze produced by dipping the
clay ware before firing into a suitable preparation and then burning at one firing.
The burning of Bristol stoneware heretofore has usually been performed in cases
known as saggers; this has rendered the process expensive as the saggers occupy much
space in the kiln.
For some time past Bristol stoneware has also been fired in special updraught kilns
in which the heat from the fire holes is led up to the inner walls by "bags" which
are completely closed at the sides and open only at the top and the products of com-
bustion are taken off from the kiln at the top. Such kilns require a large expenditure
of fuel and the process of making Bristol stoneware in them is comparatively expensive.
According to my invention I effect a great saving in the cost of manufacture of
Bristol stoneware by altering the process of manufacture and burning without saggers
in kilns with a down draft.
"
I use kilns such as I have heretofore employed in making salt glazed goods. In
"bags
these kilns the heat from the fires is led up nearly to the top of the kiln by
and then descends to apertures in the floor which admit it to a flue passing to a
chimney. Down draft kilns have never before been used without saggers in the process
of making Bristol stoneware.
The goods are stacked in the body of the kiln and the products of combustion in
their downward course circulate amongst them.
I find that with suitable precautions this downward passage of the products of
combustion amongst the goods has no ill effects and it results in a great saving
in fuel.
I regulate the draft of the kiln by admitting more or less air into the flue passing
from the kiln to the chimney.
Dated this 3rd day of September 1886.

page_text: I HENRY DOULTON of Lambeth in the County of Surrey Pottery Manufacturer
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
This invention has for its object an improvement in the process of making the
description of pottery known as Bristol stoneware.
Bristol stoneware is the sort of pottery which has a glaze produced by dipping the
clay ware before firing into a suitable preparation and then burning at one firing.
The burning of Bristol stoneware heretofore has usually been performed in cases
known as saggers; this has rendered the process expensive as the saggers occupy
much space in the kiln.
For some time past Bristol stoneware has also been fired in special updraught kilns
in which the heat from the fire holes is led up to the inner walls by "bags" which are
completely closed at the sides and open only at the top and the products of combustion
are taken off from the kiln at the top. Such kilns require a large expenditure of fuel
and the process of making Bristol stoneware in them is comparatively expensive.
According to my invention I effect a great saving in the cost of manufacture of
Bristol stoneware by altering the process of manufacture and burning without saggers
in kilns with a down draught.
I use kilns such as I have heretofore employed in making salt glazed goods. In
these kilns the heat from the fires is led up nearly to the top of the kiln by "bags"
and then descends to apertures in the floor which admit it to a flue passing to a
chimney. Down draught kilns have never before been used without saggers in the
process of making Bristol stoneware.
The goods are stacked in the body of the kiln and the products of combustion in
their downward course circulate amongst them.
I find that with suitable precautions this downward passage of the products of
combustion amongst the goods has no ill effects and it results in a great saving
in fuel.
I regulate the draught of the kiln by admitting more or less air into the flue passing
from the kiln to the chimney.
In order that my said invention may be most fully understood and readily carried
into effect I will proceed to describe the drawings hereunto annexed.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a vertical section of the kiln I employ and
Figure 2 is a plan of the same with the cover removed.
A. A. are the bags or flues up which the products of combustion ascend. B. B. are
shelves in the body of the kiln upon which the goods are stacked-these shelves are
supported by columns C. C. As is shown a space D. D is left between the shelves
for the free passage of the products of combustion. The shelves B. B. are made
up of slabs which should fit together with sufficient accuracy to prevent the passage of
any great quantity of the products of combustion between them. It is of importance
that as perfect combustion as possible should be obtained and to ensure this I prefer to
admit air at the back of the fire holes so as to completely oxidise the fuel. The draught
is regulated by admitting air at the opening E.
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 in the
manufacture of Bristol stoneware is
The pronese no decoribed of burning it in o down draught kiln