IMPROVEMENTS IN KILNS OR OVENS FOR DRYING AND BURNING GLAZED BRICKS, BATHS, SINKS, AND OTHER ARTICLES OF POTTERY AND GLAZED EARTHENWARE."
Year: 1880

page_text: LETTERS PATENT to William Holcroft, of Stourbridge, in the County of
Worcester, Manufacturer, for an Invention of "IMPROVEMENTS IN KILNS OR
OVENS FOR DRYING AND BURNING GLAZED BRICKS, BATHS, SINKS, AND
OTHER ARTICLES OF POTTERY AND GLAZED EARTHENWARE."
PROVISIONAL SPECIFICATION left by the said William Holcroft at the
Office of the Commissioners of Patents on the 30th July 1880.
WILLIAM HOLCROFT, of Stourbridge, in the County of Worcester, Manufacturer.
"IMPROVEMENTS IN KILNS OR OVENS FOR DRYING AND BURNING GLAZED BRICKS,
BATHS, SINKS, AND OTHER ARTICLES OF POTTERY AND GLAZED EARTHENWARE."
"
My Invention has reference to such kilns or ovens as are employed for drying
and burning in a closed chamber glazed bricks, baths, sinks, and other articles of
pottery and glazed earthenware, and consists of the improvements in the said
kilns or ovens hereinafter described, by which improvements great uniformity of
temperature in the several parts of the kiln is secured, together with economy of
fuel and ready control of the temperature of the kiln.
In constructing a kiln according to my Invention I build a chamber of the required
size, preferably of a length three or four times its height, and of a breadth about
equal to its height. The roof the chamber is by preference arched, and the fire
grates and flues are arranged in the following manner :-In each of the longer
sides of the kiln a series of equi-distant fire grates are constructed, the fire grates
on one side not being opposite those on the other side, but at points midway
between them. These fire grates are below the level of the floor of the kiln and
each of them opens into a flue, which, rising from the fire place, ascends vertically
till it reaches the arched top of the kiln, then crossing the said arched top descends
vertically and opens into a horizontal flue running underneath the floor of the
kiln through its whole length and on one side of the kiln. From the relative
positions of the fire places on the opposite sides of the kiln, hereinbefore described,
it will be understood that on each side of the kiln the ascending flues of the fire
grates on that side alternate with the descending flues of the fire grates on the
other side. Thus on each side of the kiln between each fire grate and the next
[Price Rd1

page_text: one is the descending flue of a fire grate on the opposite side of the kiln. The
flame and products of combustion from the fire grates on one side of the kiln
after passing to the bottom of the other side of the kiln enter a side horizontal
flue under the kiln, as hereinbefore indicated. These side horizontal flues after
passing under the whole length of the kiln open into a middle flue on the same
level, and the flame and products of combustion after having passed in one
direction under the kiln on each side the middle flue, open at the end of the kiln
into the said middle flue, and return in an opposite direction and enter a main
flue common to two or more kilns, and from thence pass to the chimney stack.
In order to provide for the effectual heating of the ends of the kiln, I make the
end walls hollow, and construct in the hollow wall a middle partition extending
from the bottom to nearly the top of the cavity. The end fire grate has flues of
the kind herein before described, and the flame and products of combustion from
the said end fire grate crossing the kiln and descending do not pass directly into
the horizontal flue, but enter the bottom of this cavity on one side, and are made
by the middle partition to ascend in one half the said cavity, and passing over the
top of the partition to descend in the other half, and from thence pass to the side
horizontal flue hereinbefore referred to.
As the gaseous matter passing from the middle flue under the floor of the kiln
to the main flue has a high temperature, it may be utilized by being employed to
heat a steam boiler, or to effect the preliminary heating of another kiln or for
other analogous purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Holcroft in the Great Seal Patent Office on the 12th
January 1881.
"
WILLIAM HOLCROFT, of Stourbridge, in the County of Worcester, Manufacturer,
"IMPROVEMENTS IN KILNS OR OVENS FOR DRYING AND BURNING GLAZED BRICKS,
BATHS, SINKS, AND OTHER ARTICLES OF POTTERY AND GLAZED EARTHENWARE."
My Invention has reference to such kilns or ovens as are employed for drying
and burning in a closed chamber glazed bricks, baths, sinks, and other articles of
pottery and glazed earthenware, and consists of the improvements in the said
kilns or ovens hereinafter described, by which improvements great uniformity of
temperature in the several parts of the kiln is secured, together with economy of
fuel and ready control of the temperature of the kiln.
In constructing a kiln according to my Invention I build a chamber of the
required size, preferably of a length three or four times its height and of a breadth
about equal to its height. The roof of the chamber is by preference arched, and
the fire grates and flues are arranged in the following manner:-In each of the
longer sides of the kiln a series of equi-distant fire grates are constructed, the fire
grates on one side not being opposite those on the other side, but midway between
them.
These fire grates are below the level of the floor of the kiln and each of them
opens into a flue, which rising from the fire place ascends vertically till it reaches
the arched top of the kiln, then crossing the said arched top descends vertically
and opens into a horizontal flue running underneath the floor of the kiln through
its whole length and on one side of the kiln. From the relative positions of the
fire places on the opposite sides of the kiln, hereinbefore described, it will be
understood that on each side of the kiln the ascending flues of the fire grates
on that side alternate with the descending flues of the fire grates on the other
side.
Thus on each side of the kiln between each fire grate and the next one is the
descending flue of a fire grate on the opposite side of the kiln. The flame and
products of combustion from the fire grates on one side of the kiln after passing to
the bottom of the other side of the kiln, enter a side horizontal flue under the
kiln, as hereinbefore indicated.
These side horizontal flues after passing under the whole length of the kiln open
into a middle flue on the same level, and the flame and products of combustion
after having passed in one direction under the kiln on each side the middle flue,
open at the end of the kiln into the said middle flue, and return in an opposite
direction and enter a main flue common to two or more kilns, and from thence
pass to the chimney stack.
In order to provide for the effectual heating of the ends of the kiln I make the
end walls hollow, and construct in the hollow wall a middle partition extending
from the bottom to nearly the top of the cavity.
Each of the end fire grates has flues of the kind hereinbefore described, and the
flame and products of combustion pass from the said end fire grate crossing the
kiln and descending do not pass directly into the horizontal flue, but enter the
bottom of this cavity on one side, and are made by the middle partition to ascend in
one half the said cavity, and passing over the top of the partition to descend in
the other half, and from thence pass to the side horizontal flue, herein before
referred to.
I will now proceed to describe, with reference to the accompanying Drawings,
the manner in which my Invention is to be performed.
Figure 1 represents in longitudinal vertical section a kiln or oven, the parts of

page_text: which are constructed and arranged according to my Invention; Figures 2 and 3
are horizontal sections of the same; Figure 4 is a cross section of the kiln or oven
taken through one of the fire places at about the middle of the kiln; Figure 5 is
an end elevation of the kiln, the middle horizontal flue being shown in section;
Figures 6 and 7 are other cross sections of the kiln, the section Figure 6 being
taken through one of the end fire places and its nearly semi-circular flue, and the
section Figure 7 being taken through the entrance or "wicket" end of the kiln, the
said Figures 6 and 7 illustrating the manner in which the entrance or "wicket"
ends of the kiln or oven are heated.
The longitudinal section, Figure 1, is taken through the line E, F, Figures 2
and 3; the horizontal section, Figure 2, is taken through the line C, D, Figure 4,
and the horizontal section, Figure 3, is taken through the line A, B, Figure 4.
The several Figures are drawn to a scale of one inch and a half to the foot, but
the kiln or oven may be made of any required size.
The same letters of reference indicate the same parts in the several Figures of
the Drawings.
a is the closed rectangular chamber of the kiln or oven, having an arched top, in
which chamber the drying and burning of the bricks or other articles are effected;
b, b, b², are the fire grates and fire places, constructed in one of the longer sides of
the kiln, and c, c, c³, are the fire grates and fire places constructed in the other
longer side of the kiln, the said fire grates and places being below the level of the
floor of the chamber a (see the cross sections, Figures 4 and 6). The fire places b, b, b²,
on one side of the kiln are situated midway between the fire places c, c, c², on the
other side of the kiln (see Figures 2 and 3).
In the sides and arched top of the chamber a and in communication with the
fire places b, b, and c, c, flues marked c, e, and f,f, are made. I will herein after call
the said flues e, e, and f, f, the semi-circular flues. The semi-circular flues e, e, are
in connection with the fire places b, b, on one side of the kiln, and the said flues e, e,
open by the necks or branch parts e², e, into the horizontal side flue g running
under the floor of the chamber a of the kiln, through its whole length. The semi-
circular flues ff, are in connection with the fire places c, c, on the other side of the
kiln, and the said flues f,f, open by the necks or branch parts f,f, into the other
side flue h, running under the floor of the chamber a. The manner in which the
fire and heated air from the fire places ascend one side of the semi-circular flues e
and f, cross the arched top of the chamber and descend vertically the opposite side
of the semi-circular flues and enter the side horizontal flues g and h, will be best
understood by an examination of Figure 4, where the direction of the current of
heated air is indicated by arrows. It will be seen by an examination of the
horizontal sections, Figures 2 and 3, that from the relative positions of the fire
places b, b, and c, c, on opposite sides of the kiln, the ascending sides of the flues e
or fin connection with the fire places on one side of the kiln alternate with the
descending sides of the flues in connection with the fire places on the other side
of the kiln. The horizontal side flues g, h, into which the two sets of semi-circular
flues e, f, respectively open, are in communication at the end k (see Figure 3) with
the middle flue i nearly on the same level as the said side flues g, h, and the flame
and products of combustion, after having traversed in one direction under the floor
of the chamber a on each side, enter the middle flue i and return in the opposite
direction and pass into the main flue 1 common to two or more kilns, and from
thence escape to the chimney stack. Between the middle flue i and the outlet or
main flue l'is a damper n, by which the draught of the kiln may be regulated. As
the gaseous matter passing from the middle flue i under the floor of the chamber a
to the main flue has a high temperature it may be utilized by being employed to
heat a steam boiler, or to effect the preliminary heating of another kilu, or for other
analogous purpose.
The arrangement of parts for heating the ends of the kiln will be best understood
by an examination of the sections, Figures 2, 6, and 7. After the chamber a of the
kiln has been charged at the entrance or "wicket" ends of the kiln the said ends

page_text: of the kiln are closed by brickwork. In the brick work closing each of the wicket
ends of the kiln a cavity or flue p is made, the said flue being divided by the
middle partition q, which extends from the bottom to nearly the top of the cavity
or hollow in the end wall (see Figure 7). One side of the flue popens into the side
horizontal flue g by the elbow shaped fluer. The ends of the kiln are heated from
the fire places b² and c², each fire place being in connection with a semi-circular
flue, marked respectively 63, 3, similar to the flues e and f, excepting that the
flues b, c, instead of opening directly into the side horizontal flues g and h, open
by the necks at 8, 8, into the flues p at the "wicket" ends of the kiln. The heated air
and products of combustion from the fire place be or c² rising up one side of the
semi-circular flue 6s or crosses the kiln, and descending the opposite side of the
semi-circular flue enter the wicket end flue p by the neck s at the bottom of one
side of the said flue p. The heated air and products of combustion next ascend
one side of the middle partition q in the flue p, and passing over the top of the
said partition descend on the other side of the said partition, and enter the side
horizontal flue g or h, as indicated by the arrows in Figures 6 and 7.
The kiln is supported by the metal supports t, connected together by longitudinal
and cross bolts or rods u, u, the said bolts or rods being provided with coiled
springs contained in recesses at the tops of the said supports for providing for the
expansion and contraction of the kiln."
By constructing and arranging the fire places and flues of the kiln or oven in
the manner described and illustrated the uniform heating of the chamber of the
kiln at every part is secured, and the temperature of the kiln is readily controlled
by the damper described and represented. The heating of the kiln is also effected
economically.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I claim as my Invention
of "Improvements in Kilns or Ovens for Drying and Burning Glazed Bricks, Baths,
Sinks, and other Articles of Pottery and Glazed Earthenware."
First. The construction and arrangement of the fire places and flues immediately
connected therewith on opposite sides of the kiln or oven, the fire places and flues on
one side being so arranged with respect to those on the other side that (excepting
with respect to the end fire places and flues) between each two ascending flues from
the fire places on one side is a descending flue from the fire place on the opposite
side of the kiln or oven, the several fire place flues being connected with
longitudinal flues under the floor of the chamber of the kiln or oven, substantially
as herein before described and illustrated in the accompanying Drawings.
Secondly. The construction and arrangement of the end fire places and the end
flues in connection therewith, in combination with the divided flues or cavities in
the entrance or " wicket" ends of the kiln or oven, for the purpose of heating the
said entrance or wicket ends of the kiln or oven, substantially as herein before
described and illustrated in the accompanying Drawings.
In witness whereof, I, the said William Holcroft, have hereunto set my hand
and seal, this Tenth day of January, in the year of our Lord One thousand
sight hundred and sighty are
Witness,
JAMES MATTHEWS,
Stourbridge.
WILLIAM HOLCROFT. (L.S.)