IMPROVEMENTS IN KILNS
Year: 1872

page_text: LETTERS PATENT to Julius Frederick Moore Pollock, of Longclose
Works, Newtown, Leeds, in the County of York, Engineer, and
John Mitchell, of Dyson Street, Bradford, Bricklayer, for tho
Invention of "IMPROVEMENTS IN KILNS."
PROVISIONAL SPECIFICATION left by the said Julius Frederick Moore
Pollock and John Mitchell at the Office of the Commissioners of
Patents, with their Petition, on the 22nd April 1872.
We, JULIUS FREDERICK MOORE POLLOCK, of Longclose Works, New-
town, Leeds, in the County of York, Engineer, and JoHN MITCHELL,
of Dyson Street, Bradford, Bricklayer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN KILNS," to be as follows :-
1
This Invention relates to kilns of the class known as tunnel kilns, and
our improved kiln is constructed in the form of a straight tunnel divided

page_text: transversely into chambers as is usual and well known in kilns of that
class.
We arrange several fire-grates at the extreme or starting end of the
kiln, four or any other convenient number of such fire-grates being
employed.
For the more ready release of the steam or vapour arising from the
bricks or other articles under treatment we form recesses in the two
corners of each chamber which are furthest removed from the firing end
of the kiln, and these recesses are placed in communication directly
with the open air by means of chimneys upwards, and also with one
common central flue by means of openings downwards. These upward
and downward passages are provided with suitable dampers for the
purpose of closing and opening or regulating the extent of opening of
the said passages as required, and the downward passages may be
inclined in the direction of the draught.
' In some cases instead of dividing. the kiln into chambers by means of
permanent partitions as is most usually done in order to release the
steam or vapour from a portion only of the bricks or other similar
articles which may be under treatment in the kiln for the time being,
we may make temporary partition walls of dried bricks which may be
burnt while serving to form such partition walls and may be afterwards
sold, and such bricks may be replaced at cach reburning by fresh
supplies of dried bricks arranged to form the required partitions, thus
economizing space and also the heat which would otherwise be absorbed
by the partition and saving the expense which has ordinarily to be
incurred in continually renewing the partition walls as parts of the
permanent structure or building.
The recesses herein-before described must, however, be in all cases
provided at regular intervals, and the kiln must also be divided into
chambers when required for use, whether the partition walls forming
such chambers be built in a permanent form or composed of dried bricks
arranged together to form temporary walls as described. In order to
enable the burner or attendant to commence operations in the middle
or any part of the kiln small furnaces are provided and arranged at each
side at the commencement of each chamber, or just beyond each of the
recesses already described.
In constructing the partition walls, whether they be built as per-
manent partitions or as temporary partitions, they must be formed with

page_text: suitable openings capable of being opened and closed at will, and more
numerous openings being formed in the cases of temporary partitions.
To still further facilitate the exit of steam or vapour a direct opening
is formed into the centre flue between and in a line with the two side
openings, and this direct opening is supplied with a trap door or plug of
fire-clay or other suitable material, which may be opened by inserting a
rod from the top of the kiln and raising the trap door or plug when
required.
The heat after passing through any of the chambers may be caused
to return down the centre fluc to any other chamber and made con-
tinuous in its action, or nearly so, by this means, suitable dampers being
provided for that purpose.
In burning bricks from end to end of the kiln the heat in this con-
tinuous arrangement is caused to return down the centre fluc, and the
smoke and steam or vapour finally pass to a chimney stack at the firing
end of the kiln.
All the advantages of passing and returning heat are thus maintained
with one longitudinal fluc only, which serves all the purposes of return-
ing heat and taking smoke, steam, or vapour to the main chimney.
When required the side chimneys with which cach chamber is pro-
vided may also be brought into requisition in order to avoid any risk of
steaming down," and so as to provide an immediate exit for steam or
vapour and heat.
After starting the kiln and getting up the heat from the end furnaces
the burning may be maintained by coaling with dust or "smudge"
through openings in the top of the kiln provided with suitable iron
mouthpieces and covers in the usual way.
In order to get the bricks or other objects to be burnt in or out each
chamber is provided with openings in each side in the usual way, but in
our plan we leave an opening in each end of the kiln large enough for
a cart to back into, and likewise in the case of long kilns, that is, those
having more than 4 chambers, we make a transverse archway or tunnel
in the centre of the same size as the inside of the kiln itself opening at
Both ends, thus giving a middle cart entrance to the kiln on each side.
This transverse tunnel is likewise important in equalizing and com-
pensating the expansive forces at work in the building during burning,

page_text: and adds both to the strength and appearance of the building. It is
likewise a convenient arrangement for using one half of the kiln only
while the other half is undergoing repairs.
In some cases we find it more convenient than building two chimneys
to each chamber to carry two side flues along the top of the kiln, not 5
built into, but above it. These form a portion of the side walls for
carrying a roof when the kiln is roofed over, and may be united to one
common chimney at their ends, or may each be provided with onc
chimney.
·
SPECIFICATION filed in pursuance of the conditions of the Letters 1
Patent, and of an Order of the Lord Chancellor, by the said Julius
Frederick Moore Pollock and John Mitchell in the Great Seal
Patent Office on the 3rd January 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JULIUS
FREDERICK MOORE POLLOCK, of Longclose Works, Newtown, Leeds, in 1
the County of York, Engineer, and JoHN MITCHELL, of Dyson Street,
Bradford, Bricklayer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of April, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Julius Frederick Moore Pollock and
John Mitchell, Her special license that we, the said Julius Frederick
Moore Pollock and John Mitchell, our executors, administrators, and
assigns, or such others as we, the said Julius Frederick Moore Pollock
and John Mitchell, our executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for “IMPROVEMENTS IN KILNS," upon the condition (amongst others) that
we, the said Julius Frederick Moore Pollock and John Mitchell, our
executors or administrators, by an instrument in writing under our, or
their, or one of our or their hands and seals, should particularly describe

page_text: and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office on or before the Fourth day of January, in the year of
our Lord One thousand eight hundred and seventy-three.
NOW KNOW YE, that I, the said Julius Frederick Moore Pollock, for
myself and on behalf of the said John Mitchell, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof (that is to say) :-
:-
This Invention relates to kilns of the class known as tunnel kilns,
and our improved kiln is constructed in the form of a straight tunnel,
divided transversely into chambers as is usual and well known in kilus
of that class.
Fig. 1 is a transverse section in the line A, B, of Fig. 3 of our improved
kiln Fig. 2 is an end elevation of the same; Fig. 3 is a plan section
partly in the line C, D, of Fig. 1 and partly in the line G, H, of the
same Figure; and Fig. 4 is a front elevation of the kilu.
In the Drawings we have shewn the kiln divided into seven chambers
(numbered 1, 2, 3, 4, 5, 6, and 7 respectively, but any other convenient
number may be used.
We arrange several fire-grates a at the extreme or starting end of
the kiln, four or any other convenient number of such fire-grates being
employed. In the Drawing four are shown.
For the more ready release of the steam or vapour arising from the
bricks or other articles under treatment, we form recesses & in the two
corners of each chamber which are furthest removed from the firing
end of the kin, and these recesses are placed in communication directly
with the open air by means of chimneys c upwards, and also with one
common central flue by means of openings d downwards. These
upward and downward passages are cach provided with suitable
dampers e, e', (two of which are shewn in plan at Fig. 3) for the purpose
of closing and opening or regulating the extent of opening of the said
passages as required; and the downward passages may be inclined in
the direction of the draught as shewn at d¹.
In some cases instead of dividing the kiln into chambers by means
of permanent partitions such as those marked as is most usually done

page_text: in order to release the steam or vapour from a portion only of the bricks
or other similar articles which may be under treatment in the kiln for
the time being, we may make temporary partition walls of dried bricks
which may be burnt while serving to form such partition walls and
may be afterwards sold, and such bricks may be replaced at each
reburning by fresh supplics of dried bricks, arranged to form the
required partitions, thus cconomizing space and also the heat which
would otherwise be absorbed by the partitions, and saving the expense
which has ordinarily to be incurred in continually renewing the partition
walls as parts of the permanent structure or building.
The recesses hercin-before described must, however, be in all cases
provided at regular intervals, and the kiln must also be divided into
chambers when required for use, whether the partition walls forming
such chambers be built in a permanent form or composed of dried bricks
arranged together to form temporary walls as described. In order to
enable the burner or attendant to commence operations in the middle
or any part of the kiln, small furnaces are provided and arranged at
cach side at the commencement of each chamber or just beyond cach
of the recesses b already described.
In constructing the partition walls whether they be built as per-
manent partitions or as temporary partitions they must be formed with
suitable openings f¹, f, capable of being opened and closed at will, and
more numerous openings being formed in the cases of temporary parti-
tions. In permanent partitions we prefer to use holes as shown in
Fig. 1, but in temporary walls we make them more numerous and
smaller.
To still further facilitate the exit of steam or vapour a direct opening h
is formed into the centre flue between and in a line with the two side
openings, and this direct opening is supplied with a trap door or plug '
(Fig. 1) of fire-clay or other suitable material, which may be opened by
inserting a rod from the top of the kiln and raising or pushing to one
side the trap door or plug when required.
The heat after passing through any of the chambers may be caused
to return down the centre fluck to any other chamber, and made cou-
tinuous in its action or nearly so by this means, suitable dampers like
that shewn at i and downward trap doors like those shown at j being
provided for that purpose to lead into the central flue between each

page_text: pair of chambers, but the kiln we have illustrated in the Drawings is
constructed to return the heat always to the firing end of the kiln, which
we find to be the best plan.
In burning bricks from end to end of the kiln the heat in this con-
Linuous arrangement is caused to return down the centre flue k, and the
smoke and steam or vapour finally pass to a chimney stack
firing end of the kiln.
at the
All the advantages of passing and returning heat are thus maintained
with one longitudinal flue k only, which serves all the purposes of
returning heat and taking smoke, steam, or vapour to the main chimney l.
When required the side chimneys c with which each chamber is provided
may also be brought into requisition in order to avoid any risk of
steaming down" and so as to provide an immediate exit for steam or
vapour and heat, and also for cooling chambers in which the burning is
completed.
"
After starting the kiln and getting up the heat from the end furnaces a
the burning may be maintained by coaling with dust or "smudge"
through openings m in the top of the kiln provided with suitable iron
mouthpieces and covers in the usual way. In order to get the bricks
or other objects to be burnt in or out each chamber is provided with
openings n in each side in the usual way, but in our plan in the cases of
long kilns, that is, those baving more than four chambers, we make a
transverse archway or tunnel o (Figs. 3 and 4) in the centre, of the
same size as the inside of the kiln itself, open at both ends, thus giving a
middle cart entrance to the kiln on cach side. This transverse tunnel is
likewise important in equalizing and compensating the expansive forces
at work in the building during burning, and adds both to the strength
and appearance of the building.
It is likewise a convenient arrangement for using one half of the kiln
only, while the other half is undergoing repairs, the end fires for com-
mencing burning being readily constructed in the transverse tunnel in
a temporary way.
The operation of our improved kiln is as follows:-Heat is got up in
the end or first chamber by means of the fires a, the said chamber being
closed from communication with the other chambers until the steam
from the bricks has been all passed through the downward openings and
passages, and through the central fluck to the chimney stack 7.

page_text: Should it be necessary to get rid of the steam more rapidly the upper
dampers leading to the small chimneys c of the said chamber may also
be thrown open, and the central downward passago may also be used
with advantage, as it tends to centralize the draught, and make the
drying and burning more complete and uniform. When the bricks in
the first chamber are well dried it is placed in communication with the
next chamber, Number 2, by means of the openings f¹, ƒ³, in the
partition, these openings when not in use being closed by means of
bricks rendered air-tight with " daub," which bricks can be readily
removed with a rake or other suitable instrument when it is required to
open the passages. The upward and downward passages of the chamber 1
are then closed by their respective dampers, and the dampers of the
chamber 2 are opened, and the steaming of the second chamber is then
proceeded with in the manner already described, the bricks in the first
chamber being in the meantime burning. The heat is maintained in
the second and following chambers by coaling with small coal through
the openings m. When the burning has been carried to the third or
fourth chambers the end fires a may be dispensed with, and the burning
maintained by coaling through the top openings m alone. When the
burning has proceeded so far that the chambers already burnt need
cooling this operation may be hastened by opening the upper dampers
of the chimneys c of the chambers to be cooled, when the cold air will
be drawn through them by means of the draught produced by the com-
bustion in the other chambers. The side fires are used when it is
necessary to commence the burning at any of the intermediate chambers,
and are also at times useful to assist the general burning when impeded
by wet weather or other causes. When it is necessary to commence
burning in the transverse tunnel or archway o temporary cnd fires
similar to those at a are erected within it.
The heat is returned thus, say from the seventh to the first chamber,
the lower dampers e, e, of the chambers 1 and 7 are opened, and the
upper dampers e', e', are closed, the hot air from the chamber Number 7
then passes by the openings d and passages of the seventh chamber
along the central flue as indicated by red arrows. The swivelling
damper is closed, and the hot air therefore cannot pass direct to the
chimney but passes up through the transverse passages & left square
across for that purpose so as not to impede the draught, and through
their openings d (the dampers e of which are open) into the chamber
Number 1, which is provided with downward openings j, j, on each side

page_text: outside
The blue
of the central flue, communicating with the chimney fluc
the damper i, thus rendering all extra flues unnecessary.
arrows indicate the direction of the draught when burning straight
forward, the draught being taken from the firing end as far as Number 3
chamber, and thence back to the chimney.
Kilns, according to our Invention, as above described are simple in
construction, efficient and economical in working, and can by reason of
their simplicity be made at a very moderate cost.
Having described the nature of our said Invention, and in what
manner the same is to be performed, we declare that we do not claim
as of our Invention or the exclusive use of the several parts herein-before
described or referred to, except when the same are used in and for the
purposes of our said Invention, with reference to which we claim,―
First. The constructing tunnel kilus so that all the purposes of
returning heat and taking smoke, steam, or vapour to the main chimney
are effected by one longitudinal fluc k, substantially as hercin described
and illustrated.
Secondly. The construction of tunnel kilns with a transverse archway
or tunnel o, and the combination in such kilns with the recesses b,
chimneys c, and passages d, d', d³, of a single central longitudinal flue k
communicating by openings h with the drying or burning chambers
of the kiln, the whole being arranged together and operating substan-
tially as herein described and illustrated.
In witness whereof, I, the said Julius Frederick Moore Pollock,
have hereunto set my hand and scal, this First day of January,
in the year of our Lord One thousand eight hundred and seventy-
throo
Witness,
W. LLOYD WISE,
Patent Agent,
London.
JULIUS F. M. POLLOCK. (L.S.)