Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02194505 2003-09-17
T.~TLE.~~IB~YS~zs APp.~~~
FIELD OF THE. TNVENTITQ1~
The present invention relates to an apparatus for
py~-olysing recyclable hydrocarbon containing materials by
a pyrolysing batch process. The apparatus is more
particularly designed for pyrolysing used rubber tires.
zo
A process for the treatment of used rubber tires
by vacuum pyrolysis to produce liquid and gaseous
hydrocarbons and a solid carbonaceous material .is disclosed
in U.S. patent No. 4740270 dated April 2.6, 1988, inventor
Christian Ray. A similar method is disclosed by the same
inventor in U.S, patent No. 4839020 dated June 13, 1989,
this patent being directed to the treatment of petroleum
derived organic sludges or residues. The reactor described
in patent 270 is shown as a vertical container. enclosing a
series of vertically spaced heated trays, each adapted to
receive a bed of tire cuttings and each heated at a
progressively higher temperature from top to bottom of the
container. The process described appears to be a
continuous process in which case no description is gi~ren of
the type of. seals which wauld be xequired at the entrance
and exit of the reactor to perform the process under
vacuum; if mercury seals were to be used, the produced
gases and vapors would be liable to be contaminated by
mercury. This patent does not teach how to effect the
process in a batch reactor.
OBJECmS OF THE INVENTION
rt is therefore the genexal object of the present
invention to provide an apparatus for pyrolysing
hydrocarbon containing materials, more parta.culaxly under
vacuum, the apparatus being designed to carz-y out a batch
~~ 945fl5
2
"" process.
Another object of the present invention resides
in the provision of an apparatus of the character
described which is designed to pyrolyse an important
quantity of recyclable hydrocarbon containing material at
high temperature of about 400 to 500 degrees centigrade and
under a vacuum of less than about 35 mm of mercury to
obtain a maximum yield of useful oils and gaseous
hydrocarbons together with useful carbon black when such
recyclable material contain the same.
Another object of the present invention is to
provide an apparatus of the character described
incorporating a rotatable drum for containing the material
to be pyrolysed and designed to be heated at high
temperature and provided with effective seals at the drum
inlet and outlet tube to prevent entry of atmospheric air
within the drum even if the latter is under vaccum.
25
Another object of the present invention is to
provide a filtering system inside the drum to filter out
any carbon black powder from the gas and vapors discharged
from the drum during the batch process.
Another object of the present invention is to
provide a system for rapidly cooling the drum upon
completion of the process so that the drum may be unloaded
and reloaded in a minimum of time between each batching
operation.
The pyrolysing apparatus of the present invention
comprises a base structure, a drum having a front and a
back end wall and supported on said base structure for
rotation about a generally horizontal axis, drive means for
rotating said drum, said drum having an access opening in
3 2 ~ X4505
.._ said front end wall for loading materials to be pyrolysed
and for unloading solid residues, a door removably closing
said access opening in an airtight manner, heating means
located adjacent and exteriorly of said drum for heating
the same as it rotates and its contents at a high
temperature in an oxygen free atmosphere, a heat insulating
sheath spacedly surrounding said drum and secured to said
base structure, a chimney mounted on said base structure
communicating with the space between said drum and said
sheath, a stationary discharge tube having an upwardly
offset portion located within said drum and a co-axial
portion extending through said back end wall, co-axial with
said drum axis and fixedly supported on said base structure
outwardly of said drum, and sealing means between said drum
and said stationary discharge tube.
Preferably, the apparatus, further includes a
sleeve co-axial with and spacedly surrounding said
discharge tube co-axial portion, secured to the exterior of
said back end wall, back bearing means for rotatably
supporting said sleeve and for preventing axial
displacement thereof and front bearing means for rotatably
supporting said drum at said front end wall while allowing
axial thermal expansion of said drum.
Preferably, the sheath has circular end openings
co-axial with said drum and further including drum
supporting front and back discs co-axial with said drum,
secured to said end walls exteriorly of said drum, and
spaced from said end walls, heat insulation between said
discs and said end walls, said discs closing said sheath
end openings.
Preferably, the front end wall has an external
stud shaft on the exterior of and co-axial with said drum
and suppported by said front bearing and further including
a bearing support lever arm pivoted to said base structure
and to said front bearing for allowing axial displacement
~~94505
''- of said front bearing.
As an alternative, said external stud shaft and
front bearing are replaced by two rollers which support the
front end wall supporting disc on each side of the drum
axis.
Preferably, there are means to adjust the spacing
of said two rollers transverse to said drum.
Preferably, said offset portion of said discharge
tube is straight and parallel to said drum axis and a
series of filters depend from a communicate with said
offset portion.
Preferably, the offset portion of said discharge
tube has a closed end proximate said front end wall and an
internal stud shaft is fixed to said front end wall,
protrudes within said drum to rotatably support a collar
which in turn supports said offset portion adjacent said
closed end by a lever which allows longitudinal thermal
expansion and contraction of said discharge tube axially of
and relative to said drum.
Preferably, a sleeve is fixed to the insulated
disc of the back end wall exteriorly of the same, said back
bearing surrounding said sleeve and supporting the same.
Preferably, the sealing means include a sealing tube, co-
axial with said drum, secured to said drum and extending
exteriorly of the same spacedly through said sleeve, said
sealing tube rotatably surrounding said co-axial portion of
said discharge tube, and a rotary sealing joint between
said sealing tube and said co-axial portion of said
discharge tube, said rotary joint located exteriorly of
said sleeve and of said back bearing.
Preferably, said rotary joint includes a sealing
tube collar fixed to the outer end of said sealing tube, a
~1 ~4~0~
common radial pad carried by said sealing tube collar, a
discharge tube collar fixed to said co-axial discharge tube
portion, a pair of concentric radial pads sliding on and in
sealing engagement with said common radial pad, a pair of
concentric accordeon tubes surrounding said co-axial
discharge tube portion, sealingly and respectively secured
to said pair of radial pads and to said discharge tube
collar, the space between said pair of radial pads and said
concentric tubes communicating with a source of inert gas
at a higher pressure than atmospheric pressure, so as to
prevent entrance of outside air within said drum when said
drum is under vacuum and which might be due to leakage
between said common pad and said concentric pads.
Preferably, the passage between said co-axial
discharge tube portion and the inner one of said concentric
accordeon tubes communicates with the inside of the drum
through the space between said sleeve and said co-axial
discharge tube portion for connection to a pressure
transducer.
As an alternative, the rotary joint includes a
packing gland formed of two sets of packing rings pressed
against. said rotating sealing tube and secured to said
axial discharge tube portion, and further including spacer
means between said two sets of packing rings, in
communication with said source of inert gas under pressure.
Preferably, the drive means for the drum include
a large diameter gear wheel fixed to the exterior of the
disc carried by the drum back end wall and spacedly
surrounding said back bearing, and a variable speed power
drive carried by said base structure is in driving
engagement with said gear wheel.
Preferably, the chimney includes a butterfly
valve to close the same, and said sheath is provided with
ventilation openings communicating with the atmosphere and
~f94~05
--~ disposed below said drum, and trap doors for closing said
ventilation openings, whereby once said trap doors are
opened, outside air circulates by convection around said
drum and is discharged through said chimney.
Preferably, power operated blower means further
circulates cooling air within the space between said sheath
and said drum.
Preferably the drum access opening is
eccentrically disposed with respect to the drum axis.
Preferably a swinging arm is pivotally connected
to the base structure at one end and is removably pivotally
connected to said door at its other end, said arm holding
the drum door in a drum closing position and swinging said
door to an out of the way position when the drum access
opening is upper most to permit loading and unloading of
said drum.
Preferably, the door is part of a door assembly
providing means to effectively seal the door around the
drum, access opening; these means include a door support,
rotary interlocking means carried by said door support and
by said front end wall around the drum access opening to
lock said door support to said front end wall by a limited
angle of rotation of said door support relative to said
front end wall, said door being supported by said door
support for relative axial movement but against relative
radial movement. A nut is secured to said door support, a
screw is screwed within said nut and pushes a pressure pad
against the center of said door; a screwdriver is mounted
within a sleeve for rotation therewith and for limited
axial movement between advanced and retracted positions
respectively engaging and releasing said screw; a handle
carried by said screwdriver for axially shifting and
rotating the same and also for axially shifting said sleeve
relative to said screwdriver and for rotating said sleeve;
2194505
.- inter-engagable means are carried by said door support and
by said sleeve which are inter-engaged and released in
respective advanced and retracted positions of said sleeve.
Therefore, the sleeve is advanced and rotated by the handle
to rotate and lock the door support, then the sleeve is
retracted and the screwdriver is advanced and rotated to
press said door in sealing engagement with said end wall
around said access opening. The door assembly is removably
supported by said swing arm through said sleeve and
permanent magnets which releasably adhere to the door
assembly.
As an alternative, the door assembly includes a
central holder and a peripheral ring secured to and
outwardly protruding from said door, heat insulation
filling said ring around said central holder, a circular
seal between said door and the edge of said access opening,
said ring registering with the door seal when said door is
in closed position, and pressure exerting means are carried
by the drum front end wall insulated disc to press said
ring against said door and the latter directly against said
seal. The door assembly is removably supported by said
swing arm through said central holder.
In one embodiment, said pressure exerting means
are hydraulic swing cylinders carried by the drum front end
wall insulated disc and clamp arms carried and actuated by
said swing cylinders between an operative position pressing
against said ring and an inoperative position clearing said
ring.
In another embodiment, said pressure exerting
means include a.threaded collar secured to drum front end
wall insulated disc and co-axial with said access opening
and through which said door may pass, and a threaded cap
releasably screwed on said collar and rotatably carried by
said door assembly, said cap having a radially inner
cylindrical flange rotatable relative to and registering
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with said ring.
Preferably, the apparatus further includes heat transmitting fins
protruding from and secured i:o the inside of said drum and extending in
planes normal
to the drum axis.
Preferably, the heat insulating sheath is provided with. a longitudinal slot
parallel to the drum axis and vertically below the same, said slot having a
length edual to
the length of said drum, said heating means including a series of burner
nozzles
1 o extending within said slot.
DESC.'RII'TIUN OF ffHE DRAWINGS
In the drawings:
Figure 1 is a schematic view of the apparatus in accordance with the
invention and of the first left hand side part of a flow diagram of th.e
f:quipment used for
the pyrolysing process.
2 o Figure 2 is a right hand side continuation of the flow diagram of figure
1.
Figure 3 is a flow diagram of the system i:or operating the gas burner of
the pyrolysing apparatus of the invention, forming part of the elements shown
in fig. 1.
2 5 Figures 4 and 5 are a side elevation and a front end view of the apparatus
of the invention.
Figure 6 is a vertical section taken along line 6-6 of figure 4.
3o Figure 7 is a partial front elevation taken in area 7 of figure 5.
9 2? X4505
""' Figure 8 is a top plan view of the swing arm for
carrying the door and taken along line 8-8 of figure 7.
Figures 9,10 and 11 are partial cross sections,
taken along line 9-9 of figure 8 and in area 11 of figure
34, showing various positions of the system for locking and
sealing the access door in position on the drum.
Figure 12 is a view similar to that of figure 8
but showing how the door is removed by. operating the swing
arm.
Figure 13 is a partial cross section taken along
line 13-13 of figure 12.
Figure 14 is a side elevation of the parts
illustrated in figure 13.
Figure 15 is a vertical cross section taken along
line 15-15 of figure 4.
Figure 16 is a longitudinal section of the
apparatus of the invention showing the rotating drum, its
support bearings, its drive, its filter assembly and
discharge tube, and the enclosing heat insulating sheath.
Figure 17 is a partial section taken along line
17-17 of figure 16.
Figure 18 is a partial section taken along line
18-18 of ffigure 16.
Figure 19 is a cross section taken in area 19 of
figure 15.
Figure 20 is a top plan view taken along line 20
of figure 16.
l0 ~1 ~~5~5
Figure 21 is a partial cross section taken along
line 21-21 of figure 17.
Figure 22 is an enlarged cross section taken in
area 22 of figure 21.
Figure 23 is a longitudinal section of a first
embodiment of the rotary joint and taken along line 23-23
of ffigure 20.
Figure 24 is a longitudinal section of a second
embodiment of the rotary joint.
Figure 25 and 26 are enlarged views taken in area
25 of figure 15 and showing the trap doors in close and
open position respectively.
Figure 27 is a top plan view of the trap door and
its operating mechanism taken along line 27-27 of figure
26.
Figure 28 is a partial vertical section taken
along line 28-28 of figure 27.
Figure 29 is a longitudinal cross section taken
along line 29 of figure 25.
Figure 30 is a partial plan view of the
insulating sheath and burners taken along line 30-30 of
figure 29.
Figure 31 is a front end elevation similar to
that of figure 5 showing another bearing system for the
front end of the rotary drum.
Figure 32 and 33 are views taken along section
line 32-32 and line 33 respectively of figure 31.
11 ~~ 94505
Figure 34 is a cross section taken along line 34-
34 of figure 16 and showing the first embodiment of the
door assembly.
Figures 35 and 36 are enlarged longitudinal
sections taken in areas 35 and 36 respectively of figure
34.
Figure 37 is a cross section taken along line 37-
37 of figure 35.
Figure 38 is a vertical section of a second
embodiment of the door assembly.
Figure 39 is a longitudinal partial section on an
enlarged scale taken in area 39 of figure 38.
Figure 40 is a partial section taken along line
40-40 of figure 38.
Figure 41 is a longitudinal section of part of
figure 38.
Figure 42 is an elevation of a third embodiment
of the door assembly, and
Figure 43 is a partial cross section taken along
line 43-43 of figure 42.
In the drawings, like reference characters
indicate like elements throughout.
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12
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
OF THE INVENTION
Referring to figures 4-7, 15- I 7, 19, ~<..~ I and 43, the apparatus of the
invention comprises a base structure 2 supporting a drum 4 of cylindrical
shape and
including a front end wall 6 and a back end wall 8 (fig 17) . End wall 6 has
an access
opening 10, which is radially ot~=set from the drum axis and which is closed
in airtight
to manner by a door 12. Drum 4 is designed to be heated up to about
500° and placed
under a vacuum of less than 35 mm Hg. Drum 4 is supported for rotation about a
horizontal axis by a front bearing 14 and a rear bearing 16 (fig 20). Drum 4
is rotated at
a variable speed by an electric motor 18, a speed reducing box 20, and a
pinion 22 (fig
20) meshing with a large diameter gear wheel 24 co-axial with the drum axis
and
secured to the back end wall 8 through means to be described hereinafter. (see
also
figure 20).
Drum 4 typically has a length of about 20 feet and a diameter of 8 feet.
2o As further shown in figs 29 and 31, drum 4 is spacedly enclosed by a
cylindrical heat insulating sheath 26 secured to the base structure 2 and
formed by
insulating ceramic panels 28 (fig 25-26) secured to the inside of a
cylindrical metal
envelope 30 by pins 32 and retainer plates 34. (See figure 30) Sheath 26 is
provided
with a longitudinal slot 36 parallel to the drum axis disposed vertically
below the same.
2s A gas burner 38, supported by the base structure 2, has a plurality of
burner nozzles 40
extending through slot 36 to directly heat the external surface of the drum 4
as the same
is rotating. Nozzles 40 (pig 30) are exposed to pilot lights 38a (figure 3)
fed by piping
extending through hole 41 at the ends of burner 38 (see figures :25, 26). The
gas flames
surround the drum 4 within the annular space 42 between the drum and the
sheath 26.
3o The burnt gases escape through one or more chimneys 44 communicating with
space 42
and vertically disposed directly above the drum axis. As shown in i-figures 15
and 19, the
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13
sheath 26 is made of two half' sections each of semi-cylindrical shape which
are united
by a joint 46. The top sheath section can be removed for the installation and
removal of
s the drum 4 and its accessories.
Figures 15 and 19 also show heat transmitting tins 48 welded to the
inside of the drum 4 and normal to the drum axis. Bins 48 increase the heat
transfer
from the drum to the comminuted material being pyrolysed but yet without
shoveling
1 o the material to the top of the drum as the latter rotates in direction of
arrow 50.
As shown in figures 15 and 25 to 30, means are provided to rapidly cool
the drum at the end of each batch operation in order to decrease as much as
possible the
time interval between each operation and during which the drum is unloaded and
15 reloaded. Aligned cooling slots 52 are made in sheath 26, parallel to and
adjacent
burner slot 36 under drum 4. lv;ach cooling slot 52 has radially inw~~rdly
tapered cross
section as shown in 26 and is closed during pyrolysing operations by a trap
door 54 (fig
6) which includes an insulating strip 56 supported by backing metal plate 58.
Strip 56
has a radially inwardly tapered shape to fit cooling slot 52 while backing
plate 58 (fig.
20 29) has a lip 60 which makes a lap joint with the edge of the metal
enveloppe 30.
Each trap door 54 is supported on the base strucl:ure 2 for movement
between open and closed position by means of longitudinally spaced pair of
lever arms
62, secured to backing plate 58 and pivoted at 64 to brackets 66 (fig 6)
bolted to the base
25 structure 2. A single acting pneumatic hydraulic cylinder 68 is pivoted to
plate 58 at 70
and to bracket 66 at 72. Extension of cylinders 68 (fig 6f produces closing of
the trap
doors 54 from the open position shown in figure 26 to the closed position
shown in
figure 25. During the pyrolysing operation, the door are closed and they are
opened
between these operations to permit atmospheric air to be sucked from under
sheath 26
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14
through cooling slots 52, space 42 and chimneys 44. if desired, drum cooling
can be
accelerated by circulating forced cooling air within space 42 by means of a
power
operated cooling fan 76, (see figure 1) connected to a tube 77 extending
through strip
56 (see also figures 6 and 26).
Referring to figures 4,6, 15, 16 and 31, it is seen that the two chimneys
44 are supported by an external sheath enclosing metal envelope 78 in turn
supported by
1 o the base structure 2. The two chimneys 44 communicate with a longitudinal
chimney
slot 80 made in sheath 26 and which extends substantially the entire length of
the drum
4. Slot 80 is diametrically opposite to and parallel to the burner slot 36.
Chimney slot
80 communicates with a superposed insulated conduit 82 extending the whole
length of
the sheath 26 on top of metal enveloppe 78 as clearly shown by comparing of
figures 4
and 5 and also shown in figure 1 ~. Conduit 82 in turn conununicatE;s with
each chimney
44 through an upwardly tapering conduit 84 (see figure 4). As shown in fig 5
and 15, an
electric air fan 86 can supply cooling air to each chimney 44 in order to cool
transducers
located within the chimneys, (see figure 1 ) just below a motorized butterfly
damper 90.
Since drum 4 must be heated to very high temperatures for the
pyrolysing operations, its two end walls 6 and 8 are heat insulated and also
the bearings
14 and 16 are heat insulated as much as possible while still supporting the
drum for
rotation. Finally, the bearings must be mounted so as to allow heat expansion
of the
2 5 drum in the axial direction.
Cylindrical sheath 26 deFne full size cylindrical openings 92 at each end
of the base structure 2 said openings 92 (fig 29) being co-axial with the drum
axis and of
a slightly greater diameter than the drum diameter.
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Referring to figures 1 f~, 17, 2 l , 22 and 29, a circular metal strip 94 is
welded to back end wall 8 and a flat ring 96 is secured to strip 94 by a
series of shoulder
5 bolts 98 each surrounded by a metal spacer washer 101 with the provision of
an
intermediate heat insulating circular strip 100. To allow for differential
radial thermal
expansion and contraction of drum 4 and ring 96, each bolt 98 extends through
a radially
elongated hole 102 made in ring 96. A clearance J of about 20 mils allow
relative radial
movement between the bolts ~>8 and the ring 96. It will be noted that at any
instant in
the rotation of the drum, the ed,uivalent of half the bolts 98 positively
support the drum.
Looking at fig 17, 20, 21, 25-26 and 29, a metal disk 104 is spacedly
secured to the flat ring 96 by metal spacers 106 welded at circular intervals
to disk 104
and ring 96. Heat insulating material 108 fills the space between ring 96 and
disk 104.
15 The assembly of strip 94, ring 96 heat insulating strip 100 and metal disk
104 is co-
axial with a drum axis. Metal disk 104 closes the circular opening; 92 of
sheath 26 and
a sealing strip, not shown, may be provided at the ,point between the rotating
disk 104
and the stationary sheath 26.
As shown in figures 6, 16 and 20, gear wheel 24 is mounted co-axial
with the drum axis on the outside of disk 104 by means of an annular suppport
110
welded to disk 104 and spacedly surrounding the rear bearing assembly 16. Disk
104
has a central hole which registers with a sleeve l 12 co-axial with the drum
axis, bolted
2 s to disk 104 and protruding outwardly of the same. hear baring 16 is a
combined radial
and axial trust bearing, preferably a spherical bearing with a double row of
rollers; it
surrounds sleeve 112 to support the same by its inner race while its outer
race is
supported on a table 116 which is part of base structure 2.
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16
As shown in figures 5, 16 and 18, the front bearing 14 is supported by a
lever arm 118 of triangular shape, (see figure 5) and which is pivoted at its
lower end by
s pivots 120 to base structure 2 so that the bearing 14 may have an axial play
as indicated
in dotted lines in figure 16 to allow for thermal expansic:>n and contraction
of the drum
as indicated by reference D.
As further shown in figs 7, 21, 29 and 34, it should be noted that the
1 o front end wall 6 is also provided with a heat insulating and drum
supporting assembly
including strip 94, flat ring 9ti, bolts 98, heat insulating strip 100 and
metal disk 104
with the spacers 106 together with the heat insulation 108. Disk 104,A for the
front end
wall 6 of drum 4 is not centrally bored and provided with a sleeve 112 but is
fitted with
an external stud shaft 122, (see figure 18;) which is co-axial with the drum
axis. Front
15 bearing 14 is mounted on stud shaft 122, as shown. Figures 16 and 18 also
shows an
internal stud shaft 124 which is co-a.~cial with rotary drum 4 and inwardly
protrudes
therein being secured to the front end wall 6 . Stud shaft 124 is welded to
end wall 6
after having being centered by fitting its inner end within a central circular
cavity 126
previously machined in the inner face of front end wall 6. A similar external
stud shaft
z o centering cavity is made in disc 104a.
During the pyrolysing operation, the hydrocarbon containing content of
the material within drum 4 is converted into vapor and gases which are
discharged to the
exterior of the rotating drum ray a stationary discharge tube 128 which is
composed of
25 three sections rigidly interconnected, namely sections 130, 136 and 138.
Section 130 is
co-axial with the drum 4, issues from the back end wall 8 of the drum 4 and is
firmly
secured to the table 116 of the structure 2 (fig 5) by clamps 132 (fig 20)
(see also figure
2). Discharge tube section 130 freely extends within a sealing tube 134 which
is rigidly
secured to the center of the back end wall 8, is sealed thereto and rearwardly
protrudes
CA 02194505 2002-10-03
17
freely through sleeve I 12 and is fitted with a rotary sealing joint generally
indicated at
137 (fig 23) which seals tube 1:34 and discharge tube section 130 as will be
hereinafter
s described and illustrated in figures 23 and 24.
Section 136 of discharge tube 128 (fig 16) (see figures 15 and 16) is
upwardly extending and connects c~>-axial section 130 with se;etion 138 which
is
horizontal, straight and extends practically the entire length of the drum 4
and which is
1 o parallel to and is vertically upwardly off=set from the dnun axis. Uffset
tube section 138
is completely closed by cap 140 at its front end and is supported through cap
140 on
internal stud shaft 124 by means of a curved arm 142 which is pivotally
connected to
cap 140 at its upper end by means of a pivot 144 while its lower end is
pivoted by a
lower pivot 146 to a collar 148 (see figure 18) which is rotatable ors inner
stud shaft 124
1 s and retained thereon by a retainer washer 126a (lig 18) . Both pivoia 144
and 146 are
horizontal and transverse to the drum axis, they allow differential thermal
expansion and
contraction in an axial direction between the drum 4 and the discharge tube
128.
As shown in figures 1S-1(i, arm 142 is curved so that: the top discharge
2o tube section 138 is maintained in a position which is laterally off=set
from the access
opening 10 of drum 4. Top discharge tube secticm l38 is provided with a series
of
elbows forming a manifold l50 to which are connected a series of filters 152
of
cylindrical shape which vertically extend within the drum 4, are closed at
their lower
end and which preferably have a wire mesh of about 4 microns. These filters,
which are
2 s laterally off set from access opening 10, are protected from the material
being loaded
through the access opening by a shield plate 154 secured to and depending from
top
discharge tube section 138. Shield plate 154 also protects the filters 152
during the
pyrolysing operation from impingement by solid material lifted as the drum
rotates in
direction 50. Referring again to figure l6, it will be noted that the vapors
and gases
CA 02194505 2003-09-17
18
circulating through discharge tube 128 do not affect rear bearing 16 since the
latter is
heat insulated from the discharge tube section 130 by the air space between
sealing tube
s 134 and sleeve 1 12.
The vapors and gases are directed by a conduit 160 fixed to tube section
130 to processing equipment which is schematically shown in figures 1,2 and 3
to be
described hereinafter.
1 o Referring to figure 16, an arm 162 is secured to the lower part of
intermediate discharge tube section 136 and extends within the drum and
carries a rod
164, the tip of which is equipped with a temperature sensor which is immersed
into the
comminuted solid material being pyrolysed.
15 Referring to figure 20, it is seen that the variable speed electric motor
18
and reducer box 20 can be laterally adjusted by bolts 166 to enable proper
meshing of
pinion 22 with gear wheel 24.
The rotary sealing joint 137 illustrated in figure 16 and 20 is detailed in
2 o figure 23; this figure shows that the stationary discharge tube section
130 is spacedly
surrounded by the sealing tube 134 which rotates since it is secured to the
drum 4. A
first collar assembly 168 formed of complementary mating collar members 170,
172,
174, 176 and 178, is rigidly secured to stationary discharge tube section 130
by set
screws 180. Similarly, a rotating collar assembly 182, consisting of
complementary
2 s mating collar members 184, 186, surrounds and is tightly secured by set
screws 188 to
the outer end of rotating sealing tube 134. Seals 190 are provided between
collar
assembly 168 and tube 1 30 and collar assembly 182 and sealing tube 134. A
radial seal
pad 192, for instance made of titanium, is carried by part 186 of the collar
assembly 182.
Seal pad 192 faces towards collars assembly 168. A pair of concentric
accordion tubes
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19
194, 196, co-axial with discharge tube 130, are fixed at one end to parts 176,
178
respectively of the collar assembly 168 and carry at their other end a pair of
annular seal
pads 192, 200 respectively supported by inner and outer seal pads supports
202, 204
s which are respectively secured to the accordion tubes 194 and 196. The seal
pads 198,
200 are pressed by the tubes 194, 196 against the common seal pad 192.
Rotating seal
pad 192 slides on the stationary seal pads 198, 200, so as to effectively seal
the outlet of
the passage between sealing tube 134 and discharge tube section 130. The
passage
defined inwardly of inner accordion tube 194, is connected by piping 208 to
transducers
1 o for recording the pressure inside the drum 4 during the pyrolysing
operation, said
passage opening into the drum by the space between tubes 130, 134. The space
between
the accordion tubes 194 and 196 is connected by piping 212 to a source of
inert gas,
preferably nitrogen, under pressure. Therefore, in the event of an accidental
leakage
between seal pads 192 and pads 198 and 200 while drum 4 is under vacuum, an
inert gas
1 s will automatically be fed to the drum instead of oxygen containing
atmospheric air.
Figure 24 shows another embodiment of rotary joint. This joint is a
packing gland 214 and includes a collar 216 secured to discharge pipe section
130 by set
screws 218 and formed with a radial flange 220 and a cylindrical pusher flange
222.
2o Two sets of packings 224, preferably made of titanium and separated by a
metal ring
226, (fig 12) are axially compressed by pusher flange 222 and inward flange
228 of a
holding and enclosing collar 230 having a radial flange 232 registering with
radial flange
220 of collar 216 and pulled towards each other by bolts 234 inserted through
spherical
washers 236. Ring 226 is provided with a hole in register with the piping 212
for
2s admission of an inert gas such as nitrogen in case of leakage of the
packings 224 which
are in frictional contact with the rotating sealing tube 134. As in the
previous
embodiment, piping 208 is connected to a sensor for taking pressure readings
within the
drum 4 through the space between sealing tube 134 and discharge tube section
130.
Spherical washers 236 allow for possible axial misalignment between tubes 130
and 134
3 o and consequently between collars 216 and 230. A seal 238 (fig 24) seals
collar 216 to
tube 130.
CA 02194505 2002-10-03
Figures 31 to 33 illustrate an alternative to the front bearing 14, stud
shaft 122 and lever support 118, previously shown in figures 16 and 18. This
bearing
system is replaced by a concentric ring 250 secured to the outside of disk
104A and
5 reinforced by inner braces 252. A pair of rollers 254 ride on the outside of
ring 250 to
support drum 4 at its front end. Each roller 254 is rotatably mounted by
bearing 255 on
a shaft 253 fitted within a U shape bracket 256 which is laterally
horizontally movable
in a slide 258 and adjustable by a screw 256 operated by hand wheel 262.
Therefore the
distance between the two rollers 254 can be adjusted so as to make a vertical
adjustment
of the front end of drum 4. Similarly, drum 4 can be adjusted in a horizontal
direction
by simultaneously horizontally shifting the two rollers to the right or to the
left. The two
rollers 254 which are made' of steel with a rounded rim allow a longitudinal
displacement of the ring 250 with respect to the same to co mpensate for
thermal
expansion and contraction of the drum 4. The two rollers are preferably
located at four
15 hour and a half and seven hour and a half' with respect to the drum axis,
the access
opening 10 being located at 12 o'clock in figure 31. hhe twa slides 258 are
mounted on
tables 264 fixed to the base structure 2.
As further shown in figs 31-34, the door I2 for closing the access
opening 10 of drum 4 is pan of a door assembly 266 (fig 9) which is removably
supported by a door supporting articulated arm 268. This articulated arm is
illustrated
more particularly in figures 5,7,8 and 12 and comprises a radially iru~er
truss 270 and a
radially outer truss 272 which are interconnected by pivots 274. Inner truss
270 is
pivoted at 276 to brackets 278 (fig 7) fixed to the sheath 26. Arm 268 swings
in a
:?5 horizontal plane and this can be adjusted by the adjustment bolts 280 for
the top pivot
276 (see figure 7). 'The outer e,nd of the outer truss 272 carries a bracket
282 by means
of pivots 284. Pivots 274, 276 and 284 are all vertical. When the door
assembly 266 is
attached to bracket 282 an operator standing on a wheeled platform 286 (see
figure 4
and 5), using a handle 288 carried by bracket 282 can swing the door assembly
into an
out of the way position with respect to the drum access opening 10 located at
12.00
o'clock. The reverse movement is effected to return the door assembly to a
drum closing
position.
CA 02194505 2002-10-03
21
Referring to figures 34 to 37, the door assembly 266 comprises the
circular door 12 which is fitted at its periphery with a gasket 290 to be
applied to the
s front end wall 6 at the periphery of the access opening 10. A door
supporting and
locking disk 292 is retained on the outside of door 6 and co-axial therewith
by means of
a series of bolts 294 and by an almular central rib 296 secured to and
projecting
outwardly from door 12 and respectively slidably engaging registering holes
and a
central cylindrical cavity of locking disk 292. Therefore, door 12 is retained
concentric
1 o with locking disk 292 but can move axially with respect to the same.
Locking disk 292
has at its periphery a series of outwardly protruding locking ears 298 which
when the
disk 292 together with the door 12 is rotated through about 35 degrees, come
into
interlocking registering relationship with mating ears 30(> inwardly
protruding from a
sleeve 302 secured to front end wall 6 and co-axially surrounding access
opening 10.
15 Rotation of the locking disk 292 is effected by applying a torque to Ears
304 which are
diametrically arranged about the door axis and secured by a bracket 306 to the
locking
disk 292.
A nut 308 is secured in a central tarred bore 310 of locking disk 392; a
2 o screw 312 is screwed within the nut 308 by means of German type threads
314; a central
pressure pad 316 is applied against the center of the dour 12 and is retained
in a cavity
318 of screw 312 by means o,f' a shoulder bolt 320. The opposite end of screw
312 is
provided with a square cavity 322 for receiving the. square tip of a
screwdriver to be
detailed hereinafter. Therefore, once locking disk 292 has been rotated to
interlocked
25 position by the torque applying ears 300, it is held against axial
rnowement away from
door 6 and therefore pressure pad 316 can be forced against the center of the
door to
firmly apply the gasket 290 against end wall 6 by rotation of screw 312 within
nut 308.
Therefore, a sealed closure is obtained for the drum even if the latter is
slightly above
atmospheric pressure.
CA 02194505 2002-10-03
22
Refernng again to figures 34, 35 and 38-39, it is seen that the door
assembly includes heat insulation 324 retained on the outside of locking disk
292 by a
metallic envelope 326. Doc:~r assembly 266 has an overall frusto conical shape
for easier
door opening and closing movement within the frusta conical cavity 328 defined
by heat
insulation 108 and its metal lining 330. If necessary, threads 314 (fig 36)
may be
greased by means of a zerk 3 32,
Zo Envelope 326 carries an inwardly protruding guide bushing 334 (fig 37)
centrally of the door assembly to guide a tool. carried by swing arm 268 (fig
8) for
removably supporting and for rotating locking disk 292 and screw 312.
This tool is illustrated in figures 8 to 11 and 13~~14. It comprises an
i 5 elongated cylindrical screwdriver 336 having a square tip 338 for engaging
screw cavity
322 and rotating screw 31;? by means of transverse handle 288 at the outer end
of the
screwdriver 336. Screwdriver 336 is axially shiftable within a locking disk
rotating tube
340 between the advanced and retracted positions shown in figure 9 and 11,
when lateral
set screws 342 carried by tube 34() reach the ends oi~ a pair o:F
diametrically opposed
20 longitudinal grooves 344 made in screwdriver 336. Tube 340 is axially
shiftable within
bracket 282 between two limit positions, namely the advanced position shown in
figure
and the retracted position shown in figure 9 and 11. Z'he outer end of tube
340 is
provided with a flange 346 which abuts against support 382 (ftg 43) in the
fully
advanced position of this tube, as shown in figure 10. In this advanced
position, locking
25 disk rotating ears 304 are engaged within a pair of longitudinal grooves
348 (fig 12)
which are diametrically opposed and longitudinally extend on the outside of
tube 340.
Door assembly support bracket 282. which is carried at the outer end of the
articulated
arm 268, is fitted with a door holder 283 to which is fixed a pair of
permanent magnets
CA 02194505 2002-10-03
23
350, see figure 12, 13 and 14., to removably adhere to metal envelope 326 of
the door
assembly to the support bracket 282 so that the door <~ssembly wall not fall
off swing
arm 268; holder 283 is further provided with push bolts 352 are screwed
against metal
envelope 326 to release the magnets therefrom.
With the magnets 350 adhering to the door assembly, figures 8 and 12
show how the door assembly 266 can be bodily withdrawn from the drum and moved
to outwardly by the folding movement of the articulated arm 268. For this
withdrawal
movement, the operator pulls on handle 288, the tool being shown in withdrawn
limit
position, as shown in figure l 1. Once the door assembly is in position within
frusto
conical hole 328, tube 340 is advanced and screwdriver 336 is retracted to the
positions
shown in figure 10 whereby tube rotation through handle 288 will rotate and
lock the
locking disk 292 with the mating ears 300 as previously described in relation
to figure
34 to 37; then the screwdriver 336 is fully advanced to the position of figure
9 while
tube 340 is retracted to clear evars 304. In this position, the tip 338 of
screwdriver 336
engages the square cavity 322 of screw 312 whereby the latter can be rotated
so as to
push inwardly against the center of the cover 12 to et~ect a perfect seal
between the
2o cover 12 and the end wall 6 of the drum. Then permanent magnets 350 are
released from
the door assembly 266 by screwing push bolts 352 and handle 288 is used to
pull the
assembly of tubes 340, screwdriver 336, bracket 282, handle 288 away from
guide
brushing 334. The assembly is swung away from the dr<un 4 by articulated arm
268.
Figures 38 to 41 show another embodiment for rernovably attaching the
door assembly to the articulated arm 268 (fig 8) and for closing access
opening 10 in a
fluidtight manner. In this case, pressure on the gasket 290 is applied in
direct register
therewith instead of applying pressure to the center of the door which might
loose its
elasticity when subjected to very high temperature. Uoor I 2 carries on the
outside a
CA 02194505 2002-10-03
24
cylindrical pusher ring 354 in register with door gasket 290. Metal envelope
326 rests
on the outer edge of cylindrical pusher ring 354. An externally threaded ring
356 is
secured to the disk 104a and protrudes outwardly from the door assembly 266a,
when
the latter is in operative position. An annular cap 358 of U shape cross
section is held
concentric with the door assembly by means of a cylindrical wall 360 secured
to
envelope 326. More particularly, the internal leg 362 of the annular cap 358
slides
axially on the cylindrical wall 360 until it abuts against the outwardly
flared edge 364 of
to wall 360. Outer leg 366 of cap 358 is inwardly threaded and can be screwed
on the
internal threads of the ring 356 so that the inner leg 3fi2, which is in
register with the
cylindrical pusher 354 will apply direct pressure on the gasket 290. To rotate
annular
cap 358, the operator insert a lever rod 368 into a radial hole 370 of annular
cap 358.
Cap 358 is rotated in the opposite direction to unscrew it from ring 356 and
allow
i s removal of the door assembly 266x. To remove the door and to retain it on
the
articulated arm 268, a rod 372 carried by the support bracket 282 (fig 7) at
the end of the
articulated arm 268 is provided with lateral bayonet pins 374 which are
inserted within
bayonet slots 376 of a holding tube 378 fixed to the center of door 12.
Operation of the
handle 288 (fig 7) will lock rod 372 within the bayonet slots 376 of holding
tube 378;
2 o release of the holding rod 37~' will leave the door assembly in closing
position on the
drum and allow removal of the articulated arm 268 so that the drum may rotate.
A
quarter turn rotation of the annular cap 358 is sufficient to firmly seal the
door 12
against the end wall 6 of the drum 4.
2 5 Figures 42 and 43 show a third embodiment for sealing the door
assembly indicated at 266b, which comprises as in the second embodiment, a
cylindrical
pusher 354 secured to the door 12 on which is applied a flat ring 380, which
is secured
to the door 12 by a conical metal envelope 326a and a disk 382 secured to
holding tube
378, the latter fixed to door 12 as in the embodiment of figure 38 and also
provided with
3o bayonet slots 376. Three angularly equally spaced awing cylinders 384 are
mounted
CA 02194505 2002-10-03
around the door assembly on the drum supporting disk 104a and provided with
clamping
arms 386. These swing cylinders with clamping arms 386 are of known
construction,
5 they are simple action hydraulic cylinders with a cam to swing open the
clamp arms 386
to a 90 degrees position shown in dotted line in figure 43 in order to clear
ring 380.
They can be operated by a manual hydraulic pump, 1-Iere again, direct pressure
is
applied against the seal 290.
to Referring to figures 1,2 and 3 there is illustrated a flow diagram of the
instrumentation and equipment used in association with the apparatus of the
invention
when the same serves to pyrolyse used tires. In a cognate patent application
entitled
"Vacuum pyrolysis of scrap tires" co-inventors, Richard l3ouziane and Rodier
Michaud,
published July 10, 1998 under Canadian patent application No. 2,194,805 a
process for
15 pyrolysing scrap tires under vacuum is described which is advantageously
carried out
within the apparatus of the invention with the instrumentation shown is
figures 1, 2 and
3. Therefore, only a succinct description of the eduipment is furrti.shed. The
apparatus
and adjacent associated equipment previously described, are indicated by the
same
reference numerals in figure 1. Used
25
~~ 945
26
,"." rubber tire cuttings indicated at 400 are loaded into drum
4 which is rotated by drive 18, 20 and heated by gas burner
180 which is initially supplied with natural gas from
reservoir 402. Drum 4a is initially evacuated by a double
stage vacuum pump 404 (see figure 2) connected to the
discharge tube 130, 160 through line 406, 408, separator
410, line 412, condenser 414 and line 416. The rubber
content of the tire clippings 400 form vapors and gases
which are filtered through filters 152; the vapors are
condensed in condenser 414 and the oil and gas mixture
flows through line 412 into separator 410 from which the
oil component is fed to oil reservoir 418 through line 420.
The oil from reservoir 418 is sold as fuel oil to be
transported by tank trucks 422. The gas component from
separator 412 is sucked by vacuum pump 404 through line
408, 406. The gases which are initially produced are poor
in hydrocarbon content and are fed to the flare 424 through
line 426. Upon the gas hydrocarbon content reaching a
minimum level, they are fed from line 426 to process gas
reservoir 428. This process gas is then used to feed the
gas burner 38 after switching off of the natural gas source
402. As soon as an exothermic reaction takes place within
the drum, vacuum pump 404 is stopped and a gas circulating
pump 430 is started to pressurize the process gas within
gas reservoir 428.
The cooling coil 432 of the condenser 414 is fed
with a water and glycol mixture from reservoir 434, this
circuit is cooled in a heat exchanger 436 by a liquid
circuit comprising the cooling water tower 438 and water
reservoir 440.
The nitrogen source connected to the rotary joint
137 through piping 212 is indicated at 442. A second
nitrogen source 444 is used for sweeping away atmospheric
air after the same has been used through air intake 446 to
effect back wash of the filters 448 on the inlet and outlet
2~ 94~~~
27
.. side of condenser 414.
A plurality of temperature, pressure and gas
component detecting sensors are installed in the oven and
equipment circuit and the data is transmitted to a central
computer through suitable transmitters. Referring to
figure 1, it is seen that chimney 44 is equipped with
sensors 450 for reading the oxygen, the carbon monoxide and
the total hydrocarbon contents of the effluent gases and
these readings are transmitted by transmittor 452 to a
control computer to operate the various valves motors and
air fans.
20
30
