Improvements in the Utilization of the Waste Heat from Cement Kilns and Lime Kilns.
Year: 1886

page_text: Improvements in the Utilization of the Waste Heat from Cement
Kilns and Lime Kilns.
I WILLIAM JOY of Stonebridge Hill Northfleet in the County of Kent Cement
Burner do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE UTILIZATION OF THE WASTE HEAT FROM CEMENT KILNS AND LIME KILNS "
to be as follows:-
My invention consists in utilizing the waste heat from cement kilns and lime
kilns for beating the air by which combustion of the fuel in the said kilns is
supported also in utilizing the said waste heat for heating air for use in drying
slurry and fuel before charging them into the kilns in which the slurry is calcined
and for use in drying chalk or limestone in a kiln before calcining it therein the
objects of my Invention being to economize fuel in cement kilns and lime kilns and
to facilitate the drying of slurry and fuel.
In utilizing the waste heat from cement kilns and lime kilns for heating the air
by which combustion of the fuel in the said kilns is supported I provide the ash
pit of the kiln or the part beneath the fire bars with means for preventing access
of air thereto otherwise than as hereinafter described and I provide for the passage
of air to the charge by means of a pipe or pipes or conduit or conduits communi-
cating at one end with the ash pit and passing through or arranged or formed
partly in the kiln above the part occupied by the charge or in a flue or flues by
which the hot gases from the burning charge are conducted from the kiln the other
end or ends of which pipe or pipes or conduit or conduits is or are open to the
atmosphere or communicates or communicate with any suitable apparatus for
forcing air such as a fan or pump. By this means the air passing to the charge in
the kiln is caused to travel through the said pipe or pipes or conduit or conduits
and is heated by the waste heat from the kiln before entering the ash pit. In
cases where the aforesaid pipe or pipes or conduit or conduits is or are open to the
atmosphere the air is caused to pass as required by the draught produced by a
chimney shaft with which the upper part of the kiln or the flue or flues leading there-
from communicates or communicate and in cases where the said pipe or pipes or
rn: 077

page_text: conduit or conduits is or are connected with forcing apparatus the air is thereby
caused to pass as required or its passage as required is thereby assisted.
In applying air heated by the said waste heat to the drying of slurry and fuel
I cause the air so heated to pass over or into and through the slurry and fuel in
any convenient manner before charging the kiln therewith. In applying air so
heated to the drying of chalk or limestone I cause air heated by the waste heat
from a kiln in action to pass through the charge in a kiln loaded with chalk or
limestone before the said charge is ignited and thus dry the said charge in the kiln
before igniting it.

page_text: Improv in the
Utilization of the waste Heat from Cement
Kilns and Lime Kilns.
I WILLIAM JOY of Stonebridge Hill Northfleet in the County of Kent Cement
Burner 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:-
My invention consists in utilizing the waste heat from cement kilas and lime
kilns for heating the air by which combustion of the fuel in the said kilns is
surpported also in utilizing the said waste heat for heating air for use in drying
slurry and fuel before charging them into the kilns in which the slurry is calcined
and for use in drying chalk or limestone in a kiln before calcining it therein the
objects of my Invention being to. economize fuel in cement kilns and lime kilns.and
to facilitate the drying of slurry and fuel.
In utilizing the waste heat from cement kilns and lime kilns for heating the air
by which combustion of the fuel in the said kilns is supported I provide the ash
pit of the kiln or the part beneath the fire bars with means for preventing access
of air thereto otherwise than as hereinafter described and I provide for the passage
of air to the charge by means of a pipe or pipes or conduit or conduits communi-
cating at one end with the ash pit and passing through or arranged or formned
partly in the kiln above the part occupied by the charge (i.e. in the walls of the
upper part of the body of the kiln or in the dome of the kiln) or in a flue or
flues by which the hot gases from the burning charge are conducted from the
kiln the other end or ends of which pipe or pipes or conduit or conduits is or are
open to the atmosphere or communicates or communicate with any suitable
apparatus for forcing air such as a fan or pump. By this means the air passing
to the charge in the kilu is caused to travel through the said pipe or pipes or
conduit or conduits and is heated by the waste heat from the kiln before entering
the ash pit. In cases where the aforesaid pipe or pipes or conduit or conduits is
or are open to the atmosphere the air is caused to pass as required by the draught
produced by a chimney shaft with which the upper part of the kiln or the flue or
flues leading therefrom communicates or communicate and in cases where the said
pipe or pipes or conduit or conduits is or are connected with forcing apparatus
the air is thereby caused to pass as required or its passage as required is thereby
assisted.
Figures 1 and 2 of the accompanying drawings are central vertical sections
(taken at right angles to each other) of a cement kiln provided with arrangements
of the kind herein before described Figure 3 is a sectional plan thereof the section
being taken on the line A Figure 1 and Figure 4 is a detail hereinafter referred
to. The same letters and figures of reference indicate the same parts in all the
Figures of the drawings.
a is the body of the kiln b is the dome thereof and b is a portion of the
chimney shaft c is the ash pit and d, d are the fire bars. The ash pit c is closed
by means of brick walls c¹, c¹ the space between which is filled with fiue dust or

page_text: other material which will effectually prevent the passage of air into the ash pit
through crevices in the said walls. e, e are the pipes through which air for the
support of combustion passes to the kiln which pipes are arranged spirally in a
recess formed in the upper part of the walls of the body of the kiln the lower
ends e, e of which pipes communicate with flues or shafts 9, g formed between the
walls of the kiln and the lining thereof and opening into the ash pit and the upper
ends e, e² of which pipes are open-to the atmosphere. When the kiln is in action
the air required for the support of combustion of the fuel in the charge enters the
pipes e, e at their open upper ends e², e² and passes through the said pipes
becoming heated by the heat absorbed by the said pipes from the hot gases passing
from the burning charge in the body of the kiln to the chimney and the air so
heated passes from the lower open ends e', e¹ of the said pipes to the flues or
shafts g, and thence into the ash pit and between the fire bars into the burning
charge in the body of the kiln the air being caused so to pass by the draught
produced by the chimney shaft. When the charge in the kiln has burnt out and
it is required to obtain access to the kiln for drawing the burnt charge the walls c¹, c¹
are removed. In order to avoid risk of fusion of the fire bars I ignite the charge
and allow combustion to proceed until the part of the charge in contact with the
bars has burnt out before closing the ash pit.
Instead of closing the ashpit by means of walls as herein before described it
may be closed by means of close fitting doors of iron or other suitable material.
Where it is required to force the air through the pipes e, e and flues g, g the
ends e, e² of the said pipes are connected with any suitable forcing apparatus.
In the arrangement shown in the accompanying drawings the pipes c, e are
protected from the direct action of the heat from the kilns by a shield of brick
work a¹. The said pipes may however be protected by a covering of asbestos or
other suitable material or they may be exposed to the direct action of the heat if
required in which case they must be formed of fire clay or other suitable material
which will not be readily injured by the heat to which the said pipes are exposed.
Where the heat is not too great iron pipes may be used in lengths of about four
or six feet the several lengths being connected in such a way as to admit of
expansion without rupture of the connections. In Figure 4 of the accompanying
Drawings a suitable method of connection for the several lengths of pipe is shown
e3, e3 being the ends of two lengths of pipe connected by a socket i which passes over
the ends of the said pipes and not being secured thereto admits of their expansion
and contraction without destruction of the joint. For a kiln of about twelve feet
diameter four pipes each of about seven inches internal diameter are sufficient but the
number and size of the pipes depends on the speed of combustion required in the
kiln. Where I use iron pipes I. prefer to surround them with or embed them in
fire clay or a composition consisting of ground furnace clinkers and portland cement
or any other material or composition which will not be rapidly injured by the heat
of the kiln. The material surrounding the pipes in the arrangements illustrated
in the accompanying drawings is marked f¹.
Where the air heating pipes are placed in a flue or flues by which the gases
from the burning charge are conducted from the kiln the said pipes may be
arranged in the said flues spirally or otherwise and where necessary the said pipes
must be protected by means of a suitable shield or covering from injury by
the heat.
I apply my improvements to lime kilns in a manner essentially similar to that
herein before described and illustrated with reference to cement kilns.
In applying air heated by the said waste heat to the drying of slurry and fuel
I cause the air so heated to pass over or into and through the slurry and fuel in
any convenient manner before charging the kiln therewith. Where the heated air
is to be so applied I arrange one end of each of the air beating pipes so that the
external air may enter them freely and I connect the other ends to a suitable
drawing and forcing apparatus by which the air is drawn through the heating
pipes and forced in the direction required. Or I otherwise connect the said pipes

page_text: to suitable apparatus by which the air is caused to pass through the said pipes
and delivered where it is required to act. In applying air heated by the said waste
heat to the drying of chalk or limestone I cause air heated by the waste heat from
a kiln in action to pass through the charge in a kiln loaded with chalk or limestone
before the said charge is ignited and thus dry the said charge in the kiln before
igniting it. In this case I prefer to cause the heated air to enter the lower part of
the charge to be dried and I provide for the passage of air through the heating
pipes and to the kiln in which it is to act in any of the ways hereinbefore described
or in any other suitable way.
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
First Utilizing the waste heat from cement kilns for heating the air by which
combustion of the fuel in the said kilns supported.
Secondly-Heating air by which combustion of the fuel in cement kilns and
lime kilns is supported by causing the said air to pass through pipes or conduits
arranged or formed in the said kilns or in flues communicating therewith substan-
tially as hereinbefore described and illustrated in the accompanying Drawings.
1
1002
W. T. WHITEMAN,
Agent for the Applicant.