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Патент USA US2112401

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March 29, 1938'.
`
R. D. HARDY ET Al.
» 2,112,401
APPARATUS FOR GOKING SOLID FUEL BRIQUETTES
Filed oct. 31. 1935
l
-
3 sheets-sheet' 2
March 29, 1938.
R, D. HARDY ET A1.
.2,M2’401
AFPARATUKS FOR COKING SOLID FUEL BRIQUETTES
Filed Oct. 3l, 1955
3 Sheets-Sheet I5
2,112,401
Patented Mar. 29, 1938l
UNITEDI STATES
PATENT i OFFICE
' >2,112,401
APPARATUS FOR ooKING SOLID FUEL
BRIQUETTES
Richard Doughty Hardy, Clifford Machen, and
Eric Haroldy George Aram, Westminster, Lon
‘ don, England, assignors t0 British Coal Dis
tillation Limited, London, England, a British>
Company
Application October 31, 1935, Serial No. 47,696
In Great Britain November 9, 1934
` 6 Claims.
provided to prevent the escape of the gases and
the volatile constituents evolved from the bri
such as briquettes, or to the distillation or heat'
quettes during the heat treatment. Provision
may also be made, for example, ‘by means of cham
bers located‘on each side of the rotatable hearth, C11
for admitting to ,the chamber in which the rotat
treatment of solid carbonaceous materials beinghereinafter termed briquettes.
According to the present invention the bri
quettes which are to be baked, distilled or sub
jected to heat treatment are fed'onto a rotating
annular hearth 01‘ grate, the rotatable hearth
or grate being preferably surmounted by a muli‘le
which forms the heating chamber so that if de
sired the heating gases maybe kept out of con
tact with the material undergoing treatment 'on
the rotatable hearth or grate, situated Abelow the
vmuflie; means being'provided for discharging the
briquettes after heat'treatment, and means being
also provided for drawing off? the volatile con
stituents evolved therefrom during the heat treat
ment. Alternatively, the briquettes may be
2O
heated by direct contact with hot gas. ' The rotat
able hearth is situated, a controlled volume of
inert` or heating gases for the purpose of> assist
ing the evolution of vapors or gases fromthe
briquettes and maintaining in suspension the
volatile constituents driven off from the bri
quettes, while lalso vaporizing any heavy or tarry
constituents Which may have settled on thev rotat
ablehearth or grate„thus carrying them in sus
pension so that they do not reach their dew p_ointA
until they pass through the exit opening or open
collectors, _condensersor the like. At the charg
ing end of the furnace, which may be situatediat
av point in the rotatable hearth chamber where
the temperature is lowest, means are provided
speed driving gear may also be provided so that the
The charging device may be constituted by a sealed Y
can be varied in accordance with the nature of
for feeding onto the rotatable hearth or grate they,
briquettes which are toundergo heat treatment.
hopper.` into which thebriquettes are fed through 25
a rotary valve or other sealing device, the hopper
the briquettes undergoing heat treatment, or
being preferably provided internally with a spiral
to Suit working conditions.
guide or feed so as to -prevent fracture or damage
«
The muiiie which is provided forfthe indirect
30 heating of the briquettes, may be in thefform of a
double roof recuperator, the'air rfor combustion
tothe briquettes in their movement through the `
said hopper from the inlet to the discharge end 30v
thereof, passing by gravity from the hopperuin
and a low pressure fan ‘being provided for deliver
ing the air to the combustion chamber of the
muñie. The combustion chamber ’situated over
the muflie may be divided so that the »iiame travels
regular and even quantities onto the rotating
furnace hearth. The outlet end of the hopper
leading from the feeding bunker to the rotatable.>
hearth may be water‘cooled and an inclined and
Water cooled plate, facing the direction of rota
towards each end of the furnace, a portion travel
ling to the discharging end so as to maintain an
even temperature, and a further volume travelling
vided for the purpose of guiding the briquettes as
they pass from the hopper onto the rotatable
being preheated in the double roof recuperator
10U
ings leading from the furnace to the gas or vapor ~
able hearth or grate, which may be annular in
plan, is operated in any suitable manner, for ex
ample, by means oían electric motor, and variable
2 CTI speed of rotation of the rotatable hearth or grate
40
(ci. 2oz-_117)
‘This invention relates to apparatus for the
heat treatment of solid agglomerated materials,
tion of the rotatable hearth or grate, may be pro
towards the charging end to- heat up the in
hearth.
comingcharge. The heating arrangements, how
vided associated with the lower end of the afore-`
A water cooled slide may also be pro-_ 405»
ever, may be such that a progressively increasing ‘ said inclined guiding plate, so that, by raising and ,
temperature is obtained from the point at Which
the solid material is charged into the furnace
r to the point where the briquettes are discharged.
Provision is made for drawing oí at one or more
points, the volatile constituents driven oif from
the briquettes during the heat treatment; a suc
tion fan or its equivalent, being provided at the
50 exit opening for the said volatile constituents,
the said exit opening being preferably situated
lowering thesaid slide intermittently or other
wise, the depth of solid material or the number of ,
superimposed'briquettes which pass onto the ro 45:5,
tatable hearth, can be regulated. For example,A
it has been found that more advantageous results
areobtained if only two superimposed layers of»
briquettes are allowed Vto pass to the rotatable>
hearth. An indicating device may be provided in 50.1";
advance of the aforesaid feeding device, con
towards the zone of highest temperature in the , stituted; for example, by a hinged plate, which
chamber containing the rotatable hearth. Suit
able seals, such as water seals or seals constituted
55 i by'as'olid material such asïcoal- dust or sand,l are
plate, according to the degree of its angular dis
placement by the briquettes fed onto-,the top ofr
the rotatable hearth, will show on the indicator
2,112,401
the number of superimposed briquettes or the
depth of the solid carbonaceous materials situated
an inclined or water cooled plate or scraper E
disposed transversely of the rotatable hearth B
and situated behind the charging end A2, this
water cooled plate or plough serving to move or
guide the briquettes from the rotatable hearth B Ul
to a discharge opening F, the discharge opening
being ñtted with a hopper and valve.
on the rotatable hearth and thereby indicate to
the operator the necessity or otherwise of varying
the position of the vertically adjustable slide ar
ranged in front of the inclined plate of the feed
ing device.
The briquettes, after traversing or being carried
round from the inlet to the discharge point of the
10 chamber containing the rotatable grate or hearth,
Y may be automatically discharged in any suitable
manner, for example, by means of an inclined and
water cooled plate or scraper disposed trans
versely of the rotatable hearth and situated
towards the charging point of the furnace, which
water cooled plate or scraper moves or guides the
briquettes from the rotatable hearth to a dis
charge opening.
In order that the said invention may be clearly
20 understood and readily carried into effect the
same will now be described more fully with refer
ence to the accompanying drawings, which show
by way of example one method and apparatus for
carrying the invention into» practice, and in which,
Figure 1 is a developed partly diagrammatic
25
vertical section through the furnace on the line
I--I of Figure 2.
Figure 2 is a partly diagrammatic plan vieW
of the rotatable hearth, and
Figure 3 is a transverse cross-section through
30
the furnace shown at Figure 1.
Figures 4, 5, 6 and 7 are transverse sections
taken at diiferent points of the rotatable hearth,
showing a modified arrangement in which pro
'vision is made for heating the briquettes or
carbonaceous material from above and from be
low.
Referring more particularly to Figures 1, 2
and 3, the briquettes which are to be treated are
40 fed into a hopper A. The said hopper A may be
provided internally with a spiral guide or feed
(not shown) so as to prevent fracture or damage
to the briquettes, the briquettes passing from the
hopper A in regular and even quantities through
45 a chute A2 onto the rotating furnace hearth B.
The outlet end A3 of the feed hopper A is pro
vided with an inclined water cooled plate A4
which faces the direction of rotation of the rotat
able hearth B and serves to guide the briquettes
50 as they pass from the hopper A onto the rotat
able hearth B. D is a water cooled level regulat
ing door associated with the lower end of the
inclined guiding plate A4 so that by raising the
lower end of the water cooled door D by suitable
55 mechanism the depth of solid material or the
number of superimposed briquettes which pass
onto the rotatable grate or hearth B can be regu
lated. C is an indicating device located in ad
vance of the feeding device A4 constituted by an
60 inclined plate, which, according to the degree of
angular displacement by the b'riquettes fed onto
the top of the rotatable hearth B, shows on an
indicator the number of superimposed briquettes
or the depth of solid carbonaceous material situ
65 ated on the rotatable hearth B, and thereby indi
cates to» the operator the necessity or otherwise
of varying the position of the vertically adjust
, '
O’ is an air inlet and P’ is a gas outlet.
Guide plates may be fitted on the side. walls
of the chamber containing the rotatable hearth
in advance of the said plate or scraper E, and the
scraper E` may be fitted with an inclined surface
or plough at the lower edge thereof, which will
automatically lift the briquettes from the rotat
able hearth, and, due to the rotation of the rotat
able hearth, discharge the same laterally from
the furnace. The discharged briquettes or the
solid carbonaceous material may pass into a
container whence the briquettes or the solid car
bonaceous materials are delivered in regular 20
quantities by a rotary valve or other sealing de
vice into a water bosh or tank where they are
quenched. Alternatively, and in lieu of using an
inclined plate such as E, extending transversely
of the rotatable hearth for the purpose of dis 25
charging the briquettes from the hearth, the
scraper which automatically discharges the
briquettes may consist of a chain provided with
a number of scraper attachments, the chain be
ing driven by sprockets which in turn are driven 30
by bavels and chains from the rotating furnace
hearth. From the said container the briquettes
may be fed through a rotary valve or star wheel
into a water trough or taken elsewhere. The
sides of the chamber containing the charging and 35
discharging gear are cased in, as aforesaid, to
prevent the evolved gases from leaking or escap
ing except at the desired point or points of col
lection, and the. aforesaid casing may be equipped
with suitable gas tight inspection doors to allow 40
access to the charging feed and discharging de
vice as, and when, required.
The rotatable hearth may be constituted by a
series of castings bolted together and ñtted with
a circular track rail running on a number of roll 45
ers situated underneath the hearth. The rollers
are mounted in suitable roller bearings, carried
by cast iron housings. To vprevent the escape of
gases from the furnace the base of the rotatable
hearth bogie B may be fitted with dip plates F2 50
which enter a water or other gas seal F', the
latter being supported by piers spaced at regular
intervals around the circumference of the fur
nace. Alternatively, the dip plates F2 may be se
cured to the stationary muiile walls, and the seal 55
channel carried on the rotating bogie, in which
case, a fixed plough removes any solid material
at one fixed point, the sealing liquid being allowed
to overflow into a collecting channel formed in
the foundation of the muflle.
60
A continuous rated motor may be provided for
driving they hearth. The motor may be directly
coupled to a double type spur gear speed reducer
mounted upon a cast iron base plate fitted with
an outboard bearing. A flexible coupling may 65
connect the motor with the speed reduction gear.
The reduction gear may drive an eccentric which
able slide D arranged in front of the. inclined is connected to a ratchet driving arm engaging
plate A4 forming part of the feeding device. The ` a rack fitted to the underside of the rotating
70 briquettes, after traversing or being carried from hearth. The whole of the said 'drive is suitable 70
the inlet A2 and being subjected to direct, indirect for operating under continuous conditions as it
or combined direct and indirect heating, are is especially robust in construction and requires
discharged from the hearth B in any suitable little attention. The speed of rotation of the
manner. For example, and in the embodiment hearth can be varied to suit working conditions.
During the passage of the briquettes around 75
75 shown, the discharging device is constituted by
2,112,401V
the furnace they are subjectedfto a graduallyV
rangements. vTo this end, the'spent`> flue .gases
increasing temperature 4whereby thev whole of
the pitch volatiles are driven off, these being
passed through coolers and the liquids condensed.
passing to the stack K are drawn off through the
pipe M and attemperated as required atf the
A The heat is applied to the briquettes as fo1lows:'--
Producer gas is admitted at ports E" to com
bustion chamber H` whereit is burned by'air
admitted through the perforated bricks G. The
combusted gas passes along the flue, H in‘vcoun
terilow to the movement of the briquettes, giv
ing up radiant heat thereto through the muifle
arch J. The spent gas, after passing completely:
around the furnace reaches the stack K. Here
the spent gas is passed to atmosphere through
the valve L if indirect heating from above only
is required. If it is desired to apply direct heat
to the briquettes, then the valve L is closed and
the spent gas passesalong the bye-pass pipe Mwhere, at N, it meets and mixes with a portion
of the stripped cooled gas drawn from the fur
nace by the exhauster O. This stripped cooled
gas serves to attemperate the spent hot gas, and
the gaseous mixture at the desired temperature,
is passed into the mufñe chamber P by the ports l
Q. A wall or baffle Q’ divides the combustionl
chamber, and forms a mixing chamber Q2 above
the ports Q. This attemperated gas is then
drawn wholly around the furnace in direct con
tact with the briquettes mixing with the pitch
‘volatiles and, drawn by the exhauster O, passes
through the condenser R `where the liquid prod
ucts are condensed, and then being driven by the
exhauster along the pipe S. The valve T serves»
to pass to atmosphere that portion of this
.V stripped gas which is not required for attemper
ating the spent hot gas.
The air may be preheated by passing between
the upper crowns of the furnace,` and may enter
the combustion chamber through small holes
40 equally spaced apart in'the lower crown of the
furnace. Gas is introduced into the furnace im
mediately below the perforate crown by means
of downtakes, and forms a more or less quiescent
blanket below the crown. The air enters the
combustion chamber in the form of numerous
jets which descend through the above mentioned
gas blanket. Combustion takes place, the flame
being generated simultaneously over the entire
length and width of the heating zone. Practi
. .cally the whole of the heat generated in the flame
is carried downwards towards the mufñe crown
and upward radiation of the ñame'tends to heat
the gas and air above it. Consequently, a large
portion of this heat is returned to the furnace.
The arrangement and detail of the>` outlets can
be modified to suit the connections to a dryer or
the like where the waste heat can be utilized.
its water seals as previously described, and a
false hearth Q5; the hot gases pass vround- this
hollow space in both directions and are exhaust
ed to atmosphere through a port (not shown-)gl
blît similar to the inlet port Q6 and situated dia
metrically opposite thereto and connected with
aL suitable stack such as K.
This stack is pro-_
vided with‘an adjustable damper.
\
Q7 is a rotating sand seal which prevents dis
tillation gases mixing with the gases which pass
to the underheating chamber Q4.
When combined indirect and direct heating is
required, the damper is closed, or partly closed,
and then all or part of the spent attemperated
gases are caused to pass from the mixing cham
ber Q2 through ports Q into the muñie chamber
as previously described.
It will, however, be seen that by adjusting the
relative pressures in the mixing chamber Q2 and
in the muflle chamber, by means of the valve
L and an exhauster O, it is possible to cause the
attemperated spent gases in the chamber Q2 to
follow either desired path, that is to say, either
all the gases may pass through the hollow hearth
and then to atmosphere, i. e., indirect heating,
or all through the ports Q and then through the
muii‘le,i. e. indirect and direct heating, or a por
tion may be passed through the hollow hearth
Q4 and then to atmosphere and a `portion through
the ports Q and then through the muflle. This
latter method is mainly direct heating but allows
a small volume of gas to pass in direct contact 40
with the briquettes or carbonaceous material so
as to act as a carrier for the distillation prod
ucts.. This method of carrying all, or a portion
of the spent gases beneath the hearth prevents
heat loss from the bottom of the briquette or 45
carbonaceous layer which, even when a most effi
cient insulator is used is bound to occur, and
materially decreases the length of time required
for carbonizing a briquette or other carbonaceous
layer of given thickness.
The aforesaid apparatus is especially suitable
for the treatment of briquettes made from rthe
semi-coke obtained from the low temperature
50 l
one side only, the time required for the heat to
distillation of coal with the aid of a suitable
binding medium, such as pitch, the baking or 55
heating operation in the aforesaid rotatable
hearth muffle furnace rendering the briquettes
smokeless and at the same time hard, dense and
not liable to fracture. Previous proposals for
baking briquettes have been open to the objection 60
that because the binding material, due to the
heat treatment, tends to fuse, they lose their
penetrate they charge is considerably greater
shape and crack or fracture so that the output
It has been found that, during the coking of
briquettes or the distillation of carbonaceous
60 materials, if a charge of carbonaceous material
or briquettes of given thickness is heated from
than twice that which is required when the same
r charge is heated from both sides.
According to a modification of the present in
vention, and in order to increase materially the
rate at which the briquette layer or the carbo
naceous materials can be passed through the
70 heating chamber by heating the layer on both
of briquettes of uniform strength and shape is
The usual method of baking, also pro 65
reduced.
duces a very large proportion of fractured or
damaged briquettes but by the present process
and apparatus, and on account of the fact that,v
during the baking operation, the briquettes are
sides the briquettes are fed upon a false hearth
relatively stationary, any liability to fracture is 70
practically eliminated, while the feeding and dis
Q5 located above a lower hearth (similar to B)
so that the briquettes or carbonaceous materials
charge arrangements are such as also to eliminate
or minimize any tendency of fracture, damage or
are heated from above and below.
75
point N before they pass into the gas mixing
chamber Q2. Thence they pass by a brick-lined
duct Q3 into a port Q5 situated at the hearth
level B, and communicating with a hollow space
Q4 formed between theexisting hearth B ,with
_
Figures 4, 5, 6 and 7 show these modified ar
breakage at these points.
We claim:
4
p 2,112,401;
1. An annular furnace for> 'heat treating bri
quettes comprising side walls and a top, a per
forate crown spaced substantially below said top,
its ends terminating in said side walls, a muflie
arch disposed below the perforate crown and
spaced therefrom a substantial distance with its
ends terminating in said side walls, an annular
rotatable horizontally disposed hearth below the
muii‘le arch and having its edges spaced from the
10 furnace walls and sealing means secured to said
rotatable hearth for sealing the bottom of the
furnace.
Y
2. An annular furnace for heat treating bri
quettes comprising side walls and a top, a per
forate crown spaced substantially below said top,
its ends terminating in said side walls, a mufile
arch disposed below the perforate crown and
spaced therefrom a Substantial distance with its
ends terminating in said side walls, an annular
20 rotatable horizontally disposed hearth below the
muffle arch and having its edges spaced from the
furnace walls and sealing means secured to said
rotatable hearth for sealing the bottom of the
furnace, said sealing means comprising depend
ing trough-shaped receptacles adapted for seal
ing engagement with depending plates secured to
the inner walls of said furnace.
3. An annular furnace for heat treating bri
quettes comprising side walls and a top, a per
30 forate crown spaced substantially below said top,
its ends terminating in said side walls, and means
for introducing air between said top and per
forate crown, a muiiie arch disposed below the
perforate crown and spaced therefrom a sub
stantial distance with its depending ends termi
nating in said side walls, and means for intro
chamber being separatedby a perforate crown
wall, a muille chamber immediately below said
combustion chamber and commensurate therewith
and separated therefrom by an imperforate mufñe
arch, and an annular horizontally disposed ro
tatable hearth positioned to move through said
mufi’le chamber, said hearth being provided with
means on its under surface for sealing the mufile
chamber from the atmosphere.
5. An annular furnace for heat treating bri
quettes comprising an air preheating chamber,
said chamber being provided with means for the
introduction of air, a combustion chamber imme
diately below said preheating chamber and con
centric therewith, the walls of said combustion
chamber being provided with spaced apertures
for the introduction of combustible gases, said
combustion chamber and said preheating cham
ber being separated by a perforate crown wall, a
muñ‘le chamber immediately below said combus
tion chamber and commensurate therewith and
separated therefrom by an imperforate muiile
arch, and an annular horizontally disposed ro
tatable hearth positioned to move through said
muñle chamber said hearth being provided with
means on its under surface for sealing the muiile
chamber from the atmosphere, said sealing means
comprising depending trough-shaped receptacles
adapted for sealing engagement with depending
plates secured to the inner walls of said furnace. 30
6. An annular furnace for heat treating bri
quettes comprising an air preheating chamber,
said chamber being provided with means for the
introduction of air, a combustion chamber imme
diately below said preheating chamber and con 35
centric therewith, the walls of said combustion
ducing combustible gases between said perforate
chamber being provided with spaced apertures
crown and said mufile arch, an annular rotatable
for the introduction of combustible gases, said
combustion chamber and said preheating cham
ber being separated by a perforate crown wall,
a muíi‘le chamber immediately below said combus
tion chamber and commensurate therewith and
separated therefrom by an imperforate muille
arch, and an annular hollow horizontally disposed
rotatable hearth positioned to move through said
muñle chamber and means for circulating heated
gases through said hollow hearth, sealing means
between said hollow hearth and the muffle cham
ber, and sealing means secured to said rotatable
hearth for sealing the mufñe chamber from the
atmosphere, and means for withdrawing the
generated gases from said muiile chamber.
RICHARD DOUGHTY HARDY.
CLIFFORD MACHEN.
ERIC HAROLD GEORGE ARAM.
horizontally disposed hearth below the muñ‘le arch
40 for the reception of briquettes and having its
edges spaced from the furnace walls, sealing
means secured to said rotatable hearth for sealing
the bottom of the furnace and means for with~
drawing the generated gases from the space be
tween the muflie arch and the bottom of the
furnace.
4. An annular furnace for heat treating bri
quettes comprising an air preheating chamber,
said chamber being provided with means for the
50 introduction of air, a combustion chamber im,
mediately below said preheating chamber and
concentric therewith, the walls of said combus
tion chamber being provided with spaced aper
tures for the introduction of combustible gases,
said combustion chamber and said preheating
40
45
50
55
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