Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to kilns for curing
molded concrete products, and particularly green cement
blocks supported on pallets, in much shorter time periods
than has been possible heretofore.
In production plants producing quantities of
cementitious blocks in production lines having automated
machinery for making and handling the block produced, it
is important to cure the green blocks produced at an
accelerated rate which does not require the many hours
of steaming and soaking which have been deemed necessary
in past systems.
Recently, designers have sought to build systems
in which block can be continuously processed under well-
controlled conditions and some have utilized circular
tunnels which are open at one side to permit blocks to be
automatically loaded and unloaded from the racks which travel
in the circular kiln tunnel. I refer particularly to
the Anderson United Statespatent No. 3,545,733 and the
LaForest patent No. 2,969,577 which are typical of prior
art structures. Rack carriers, which substantially engage
the walls of the tunnel in which they move, so as to
provide isolated treating compartments within the tunnel
in which they move, have also been used (see Nerge United
States patent No. 3,234,661) and more recently such racks
for carrying cement block have been used in a circular
- tunnel of the Anderson type in several commercial appli-
cations. The present invention relates to certain im-
provements in such systems which will be described and
are delineated in the claims.
One of the prime objects of the present invention
is to provide a superior kiln which is capable of producing
high quality products in a relatively short curing time such
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as 5 hours, using available aggregates and cements (i.e. type
I) in the area in which the kiln is to operate.
A further object of the invention is to provide a
continuous and uniformly controlled curing kiln, particularly
for the concrete block industry, wherein novel blade assembly
seals are provided at predetermined circumferentially spaced
locations within a circular processing tunnel to cooperate
with carousel chassis-mounted racks which engage these seals
to provide isolated sections or compartments within the tun-
nel whose recirculated atmosphere is so eontrolled that thehydration of the cement is accomplished, in a manner to pro-
vide uniformly high quality products.
A further object of the invention is to provide an
automatic system of the character described which permits
the high speed operation of the associated block-making and
other handling equipment in an economic manner.
Still another object of the invention is to design a
kiln of the type indicated which requires substantially no re-
pair or maintenance and operates completely automatically to
process the blocks on a first in - first out basis, through a
controlled atmosphere in aceordanee with the eomposition of the
bloek being proeessed.
Another objeet of the invention is to provide an
improved earousel strueture wherein a ehassis made up of
areuate seetions, having spaeed apart raek mounts, is pro-
vided for supporting the raeks whieh travel in the kiln system.
Still another objeet of the invention is to provide
a system of the eharaeter deseribed wherein heated air with
entrained steam is introdueed into steam eompartments, reeir-
eulated, and wherein added steam is entrained in the reeir-
eulated flow dependent on eonditions measured within the
partieular eompartment.
A still further objeet of the invention is to
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design a kiln system of the character described wherein an
improved carousel indexinq mechanism is employed.
Still another object of the invention is to provide
a continuous kiln of the type mentioned wherein the rack
carousel is supported on an automatically self-aligning sys-
tem of independent rollers which can individually accommodate
to the carousel surface which they support at a given moment.
Other objects and advantages of the present inven-
tion will become apparent to those of ordinary skill in the
art as the description thereof proceeds.
An improved carousel comprising a chassis with
spaced apart rack carriers mounted thereon is moved on guides,
such as guide rollers, provided in a circular kiln tunnel.
The rack carriers, while sidewisely open, have substantially
imperforate end and top and bottom walls, and a substantially
imperforate radial wall, and cooperate with circumferentially
spaced groups of seal blades mounted in the tunnel to form
sealed compartments between the groups as a result of the
carriers being stopped in indexed position at predetermined
locations in the tunnel. Hot air with entrained steam is
introduced into certain of the compartments and recirculated
continuously.
Figure 1 is a schematic top plan view of the kiln
with portions of the annular tunnel roof and carousel racks
removed in the interest of clarity;
Figure 2 is an enlarged, fragmentary, transverse,
sectional view taken on the line 2-2 of Figure 1, and illus-
trating the mechanism for introducing heated air with en-
trained steam to those portions of the kiln tunnel which
employ it in the processing operation;
Figure 3 is an enlarged, fragmentary, transverse,
sectional view taken on the line 3-3 of Figure 1, and particu-
larly illustrating the construction of a rack carrier, and
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mechanism for indexing the carousel and racks around the kiln;
Figure 4 is an enlarged, fragmentary side eleva-
tional view taken on the line 4-4 of Figure 3 to particularly
illustrate the carousel indexing mechanism, the chain lines
illustrating a tilted, inoperative position of the rack
engaging dog;
Figure 5 is a top plan view thereof;
Figure 6 is an enlarged, top plan schematic view
of several racks illustrating the manner in which products
are supported by the shelves of the rack carriers;
Figure 7 is an enlarged, fragmentary, transverse
sectional view, taken on the line 7-7 of Figure l, and par-
ticularly illustrating the tunnel seal blade assemblies which
define the kiln processing compartments;
Figure 8 is a sectional plan view taken on the line
8-8 of Figure 7;
Figure 9 is a top plan view of a carousel chassis
section;
Figure lO is an end elevational view thereof, taken
on the line lO-10 of Figure 9;
Figure 11 is a perspective, plan view of a wiper
pan which is mounted on the underside of the chassis section
under each rack mount fabrication which is provided thereon;
Figure 12 is a schematic, electrical control system
diagram;
Figure 13 is a transverse sectional view, similar
to Figure 3, illustrating a preferred form of carousel sup-
port system;
Figure 14 is an enlarged fragmentary view of a sup-
port element used in the system; and
Figure 15 is a side elevational view thereof.
Referring now more particularly to the accompanying
drawings, and in the first instance particularly to Figure 1,
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a letter K generally designates the kiln or kiln frame which
includes octagonal inner and outer siae walls 10 and 11, re-
spectively, covered by a top wall 12. The walls 10 - 12 are
of insulated character, comprising, for example, a foam plastic
core sandwiched between inner and outer metal sheets, and the
walls 10 - 12 together form an enclosure open along its bottom
which can rest on the concrete floor 13 of a concrete block
manufacturing plant (see Figure 3).
The inner and outer walls 10 and 11 have a break or
opening lOa and lla respectively, provided for purposes of
permitting access for a loader machine, generally designated
L, and an unloader machine generally designated U, which load
palleted blocks to, and unload palleted blocks from, the kiln
K. As Figure 1 indicates, bulkheads 14 - 22 divide the en-
closure K into a series of arcuate compartments 23 - 30, the
purpose of which will presently become apparent.
Provided within the enclosure K and extending
through the compartments 23 - 30, are a series of pedestals
31 (Figure 3) which bolt to plates (not shown) embedded in
the floor 13. The pedestals 31 are bifurcated at their upper
ends and mount cross pins 33 on which guide rollers 34 are
freely rotatable. Also provided on like pedestals 31, are
horizontal rollers 35, journaled on vertical pins 33a which
are operative to engage the chassis assembly of a carousel
generally designated C, which will now be described.
The chassis assembly (Figures 3 and 9 - 11), which
forms the base framework for the carousel, comprises circum-
ferentially abutting arcuate sections A (one section and a
fragmentary portion of the next adjacent section being shown
in Figure 9) each consisting of arcuate inner and outer
tubular members 36 and 37, respectively, joined by pairs of
radially extending channel members 37a and by end members 37b.
The end members 37b may be bolted or otherwise secured together
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to fix the arcuate sections A in circular formation. Welded
in position radially intermediate the tubular members 36 and
37 are arcuate bar members 38 and 39 which secure to the
undersides of members 37a and 37b. It is to be understood
that the pairs of channels 37a function as mount plates for
rack carriers, generally designated R, which bolt to their
upper faces as at 40. Welded in position between the bars
38 and 39 are thrust blocks 41, which in a manner to be de-
scribed, are engaged by indexing mechanism (to be described)
for moving the carousel C around the kiln enclosure K.
As Figures 3 and 6 indicate, each wedge-shaped rack
R includes sets of outer, upright angle members 42, inter-
mediate angle members 43, and inner butting angle members 44.
Welded to the upper and lower ends of the angle members 42,
43 and 44 are solid, imperforate upper and lower walls 45 and
46, respectively, which completely cover the upper and lower
ends of rack R, and it will be observed that it is bottom walls
46 which bolt to the chassis members 37a. While the radial
sides of racks R are open, imperforate solid end walls 45a and
46a completely cover the ends of each rack R as indicated in
Figures 3 and 6. Also, a solid, imperforate, radially extend-
ing partition 47 effectively segregates one side of the rack
R from another. Welded to the angles 42 - 44 are vertically
spaced, horizontally disposed, radially extending angle bars
47a which provide a designated number of shelf members 47a
(in this instance nine) as predetermined by kiln requirements.
In a typical installation, the shelf members 47a will support
a series of pallets P (such as six) which may typically sup-
port three concrete blocks apiece, the pallets and products
being supported between the opposing shelves 47a of adjacent
racks R as particularly indicated in Figure 6. Provided on
the chassis assembly below each rack R is a wiper pan member,
generally designated 48 (Figure 11), which is intermediately
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recessed as at 48a to accommodate the bars 39. The pans 48
are welded to the members 37a and 39 to further seal the
bottoms of racks R.
Provided at each of the bulkheads 14 - 22 are rack-
surrounding wiper blade assemblies generally designated W
(Figures 1, 7 and 8) which are shown in detail in Figures 7
and 8. Each of the wiper assemblies W includes four separate
side, bottom and top wiper units 49a, 49b, and 49c respec-
tively, which are so positioned as to each be engaged by a
rack R passing therethrough. The construction of the wiper
units 49a - 49c is identical so the construction of only one
will be described-in detail. In Figure 8, one of the bulk-
heads 16 is shown as supporting a vertical plate 49 ha~i~g
spaced apart angle members 50 fixed thereto. Opposite angle
members 50 are supported by a like frame strip or wall 49.
Each of the angle members 50 supports a resilient rubber
wiper blade 51, which, for example, may be made of a flexible
resilient neoprene material. The spacing between blades 51,
which typically might be eight inches, for instance, is some-
thing less than the distance _ (Figure 6) constituting thewidth of each rack R at its inner end (which might typically
be ten inches) so that there will always be at least one blade
50 (and preferably two) in contact with the end surface of the
indexed rack R when the rack is halted in indexed position.
Further, the over-all depth b of each wiper unit
49a - 49c is so predetermined as to be always greater than
the space c (Figure 6) between racks R. This, with proper
indexing, assures that, when the racks R are stopped in
indexed position, there always will be a rack R at each
wiper unit W, thus effectively isolating each of the compart-
ments 23 - 30.
Provided to index the racks R of the carousel C a
predetermined distance d (Figure 6), which insures that a
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rack R Will always be disposed in radial confronting position
with relation to each of the wiper units W, are a pair of
carousel indexing units I. Figures 1, 4 and 5 particularly
illustrate the indexing units I which are utilized, as shown
in Figure 1, at generally radially opposite locations. Fixed
in position at the bottom of compartment 24 and the loading-
unloading zone, are frameworks generally designated 52, Figures
4 and 5, which include a bottom plate 53, and a top plate 54,
connected by spacer members 55, the spacers 55 being spaced
apart for a purpose which will presently be described.
The top plates 54 include openings 56 with arcuate
walls 56a and 56b (Figure 5) conforming to arcs taken on the
axis of revolution of the carousel C. Mounted to move back
and forth along opening 56 is a carriage 57 mounting dependent,
horizontally disposed, rollers 58 which engage the walls 56a
and 56b of the opening 56 and assure that the carriage 57
will be moved in an arcuate path corresponding to the arcuate
path in which the carousel chassis thrust blocks 41 (Figure
9) are moved. Also provided on the carriage 57 are sets of
upper and lower guide rollers 59 and 60, respectively, which
travel along the plate 54 at the edges of opening 56.
Mounted on a platform 61, atop each carriage 57, is
a carousel pusher assembly comprising support bars 62, journal-
ing a pin 63 on which a dog member 64 is eccentrically pivotally
mounted. The dog member 64 has a locating key 65 for engage-
ment with platform 61, as shown in Figure 4, when the dog is
in rack indexing position, and also includes a stop member 66
which limits the extent of its movement beyond the inoperative
position (shown in broken lines in Figure 4). It will be ob-
served that the dog 64 is mounted off-center so that it will
always be gravity-returned to the position in which it is
shown in Figure 4.
Provided to reciprocate each carriage 57 is a
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double acting, hydraulic cylinder 67, disposed inside the
inner wall 12 as shown, so as to separate the cylinder 67
from the atmosphere of the kiln treating compartments. Each
cylinder 67 includes a piston rod 67a, to which a chain 68 is
connected which passes through an opening 74 in wall 12 around
a sprocket 69 journaled on a pin 70 provided on the platform
assembly 52. The chain 68 is connected to the indexing car-
riage 61 by a suitable coupling member 71. Also connected to
the piston rod 67a is a return cable 72 which passes around
an idler pulley 73 mounted within the inner enclosure wall 12
and which extends through a similar opening 74 in inner wall
12 to a series of idler pulleys 75, 76 and 77, and finally
connects to the carriage at 78.
Figures 1 and 2 illustrate the mechanism for sup-
plying hot air, or hot air and steam, to the treated compart-
ments. In Figure 1 an oil heater unit 79, which supplies hot
- oil to the heating system now to be described is shown. Hot
oil from the heater 79 is pumped via supply lines 80 to a
circular manifold 81 and via lines 80a to a series of fin tubes
or coils 82 (Figure 2) disposed in the vertical air supply
heater assembly H, which is depicted in Figure 2. The oil
returns through a manifold 81a and return lines 80b and 80c.
The assembly in Figure 2 provides a tubular vertical duct 83
to receive air from a blower fan 84 which moves it to a lower
manifold 85, connected with a duct 86 which, as Figure 1 in-
dicates, extends radially to the inner side of the indexing
pathway of the racks R. At the upper end of the unit, a re-
turn duct 87 receives the atmosphere of the particular com-
partment and returns it to fan 84 for recirculation. The
units H in compartments Z3 and 24 are constructed as described
thus far. In those compartments 25 - 28 which also require
the injection of steam under pressure, a steam pipe 88, sup-
plied with steam from a suitable source such as a steam boiler
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which may be disposed within the inner wall 12 adjacent to oil
heaters 79, has nozzle ports 89 which inject the steam S in a
countercurrent direction to the air which is being forced
through the system in the direction of arrows x by fan 84.
Alternatively, pipe 88 might be a water pipe
releasing water under tap pressure in a fine stream through the
fine nozzle ports 89 into the heated air stream for instant
vaporization to provide the requisite entrained steam. In
compartments 29 and 30 no unit heater H is utilized and,
rather, cooling fans 90 are provided to introduce ambient air
at room temperature to compartment 30 (which then is exhausted
through ducts provided in the roof of the enclosure). Com-
partment 29 is a bleed off chamber from which steam vapor
may be removed by roof fans.
Figure 12 illustrates a typical circuit in which a
circuit line 1-1 connected across a power source represented
by lines L-l and L-2 includes a fan motor 84 and a thermostat
T. There would be such a line 1-1, including the components
described, for each of the compartments 23 and 24, which
utilize heated air only (no steam) and comprise presetting
compartments in which the blocks take a preset at elevated
temperatures which typically might reach llO~F. When the
thermostats T in either of chambers 23 and 24 indicate that
the temperature is falling below such a preset level, the fans
84 in these compartments will be turned on to blow warm air
past the fin tubes 82 and raise the temperature to the desig-
nated level once again. The oil heater 79, which includes a
continuously operated pump, supplies hot oil to all of the
fin tubes 82 in the system.
Lines 1-2 are utilized for each compartment 25 - 28
which receive entrained steam in the heated air, and a humidi-
stat ~ is utilized in each compartment to operate a solenoid-
opened valve V, when the humidity falls below the designated
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level. A parallel line 1-3 for each line 1-2 includes the
thermostat T provided in each compartment 25 - 28. It will
be noted that the valve V can be opened to provide entrained
steam only when the fan 84 is operating, whereas the fan 84
in each of these compartments can supply heated air without
steam, when so directed by the thermostat T in the particular
compartment. The temperature may be gradually increased to
190F as the blocks proceed from compartment 25 to compartment
28, with the thermostats being set in compartments 25 - 28 to
maintain typical intermediate levels therein respectively.
At the right end of the kiln in Figure 1, the
loader L loads the palleted blocks sequentially to the shelves
47a of adjacent racks R to dispose them in the supported posi-
tion illustrated in Figure 6 at a time when the carousel C is
halted in an indexed position. At the same time, the unloader
U unloads pallets sequentially from the racks R which have
moved into the unloader zone from the compartment 30. Such
loading and unloading equipment is commercially available and
need not be described here.
Once loading and unloading has been accomplished,
the pair of cylinders 67 are concurrently activated to move
carriages 61 in a clockwise direction in Figure 1, to the end
position in which they are shown in Figure 1, dogs 64, being
in the upright position shown in Figures 4 and 5, and engag-
ing one of the thrust blocks 41 to move the carousel C clock-
wisely an increment such as to advance the carousel the distance
d. The indexed distance d is predetermined to halt the follow-
ing rack R in each instance in a position radially opposite a
wiper assembly W so that when the carousel C is halted in
indexed position, there will always be a rack R sealing each
of the wiper units W and effectively isolating each of the
compartments 23 - 30. The double acting cylinders 67 are
then immediately reversed, so that cables 72 return the
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carriages 61 in a counterclockwise direction. When the in-
dexing dogs 64 contact the following thrust block 41, their
cam surfaces 64a will move them to the tilted, inoperative
position shown in chain lines in Figure 4, so that they pass
beneath the following thrust block 41 to the opposite side
(counterclockwisely) thereof. Finally, when the carriages
61 are in halted, return position, the dogs 64 will have been
moved counterclockwisely slightly beyond the following thrust
blocks 41 and will be gravity restored to the solid line posi-
tion illustrated in Figure 4. The spacer blocks 55 (seeFigure 4) are so spaced apart that the carriage 61, sans
lower wheels 60, can be readily assembled (and lower wheels
60 then readily engaged).
The carousel C is indexed through identical distances
d in a uniformly timed manner, such that èach product processed
requires the same amount of time to proceed from the loading
machine L to the unloading machine U, and since conditions in
the kiln K are rigidly controlled, it should be clear that the
blocks will all be subjected to identical curing conditions and
will be cured uniformly.
It has been determined in practice that a carousel
cannot be fabricated so precisely, on a production basis,
that its lower, roller engaging surface extends in a common
horizontal plane. With the structure disclosed in Figure 3,
carousel breakdown problems have occurred because of minimal
differences in the level at which rails 36 and 37, for
instance, ride, and because the lower surfaces of rails 36
and 37 themselves do not uniformly lie in a common horizontal
plane. This misalignment, due to irregularity in the fabrica-
tion of the carousel, tends to force the carousel off centerand tends to produce a ride condition in which the edges of
the rollers 34 and 35 are in engagement with the rails 36 and
37, and tend to score them. Moreover, the life of rollers 34
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and 35, with the heavy load carried by the rack carriers undermisaligned conditions, has been found to be short.
To obviate these difficulties, an improved version
of the invention includes a series of circumferentially abut-
ting arcuate wear strips 100, welded to the lower surfaces of
rails 36 and 37. It is to be understood that the entire kiln
structure remains the same in this modified embodiment of the
invention, except for the changed construction (including
wear strips 100) which will now be described, wherein the
rollers 34 are supported for restricted universal movement
as well as rotation.
In the modified embodiment, the rollers 34 are
used in pairs, as indicated particularly in Figure lS, and they
are journaled on bushings 101 provided on transversely or
radially disposed pins 102. The bushings 101 may suitably
be bronze bushings of a type which may be readily procured
in the marketplace.
The pins 102 are supported by a generally box-like
roller mount frame structure, generally designated 103, which
20 i5 itself pivotally supported by a pivot pin 105 which extends
transversely or radially as indicated. The pin 105 is sup-
ported by an intermediate frame mount 106, journaled by
similar bushings 107 provided for a pin 108 supported by the
fixed base mount structure, generally designated 110, which is
fixedly supported on the bed 13.
Each of the pins 102, 105, and 108 is notched or
flatted as at 99 and each is prevented from rotating by a
keeper plate 109. As Figures 14 and 15 indicate, the base
mount 110 includes a bottom anchor plate 111 which may be
bolted or otherwise fixed to the concrete floor 13.
The base structure 110 includes a pair of end
walls 112 and a pair of side walls 113 and the roller mount 103
includes side walls 114 joined by end walls 115. Supports 116
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are fixed on side walls 114 and include lower portions 117having openings 118 for journaling the roller mount structure
103 on the pin 105.
Each of the pins 102, 105, and 108 includes a
suitable cotter pin "c", and a grease filling "g" to provide
proper lubrication. The intermediate frame structure 106
comprises side plates 119 with end members for supporting
bushings 107. Pivoting movement of the intermediate frame
structure 106 on bushing 107 is limited by the engagement of
the lower surfaces of plates 119 with the upper surfaces of
base plates 113 and typically a space of about 1/16" is left
between these members. This permits a limited pivoting of
frame structure 106 and the structure 103 and wheels 34,
which it carries, in a radial plane or direction as indicated
by arrow "a".
The pivoting of intermediate frame structure 103
; on pin 105 in what may be termed a generally circumferential
plane, or a vertical plane, as indicated by arrow b, is
limited by engagement of the side plates 114 with the end
plates 112 of base structure 110, and typically a 1/16" space
is also provided between members 114 and 112.
The wear strips 100 are preferably constructed of
"jalloy" plate of 400 to 500 Brinell hardness and these are
engaged by the wheels 34 which typically may have a hardness
factor of 360 Brinell. Shims are, in some instances, used
between the base plates 111 and the floor 13.
In practice, each pair of rollers 35 has essentially
a restricted universal pivoting movement with relation to
either the rail 36 or the rail 37 which it is supporting, and
is capable of universally rocking to accommodate to irregu-
larities in carousel chassis construction, to the extent that
- line contact across the width of wheels 34~ as indicated in
Figure 13, is maintained by these load-bearing surfaces. ~ith
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the structure described, down-time is not a material economic
factor in the operation of the circular kiln systems which
have been described.
It is to be understood that the drawings and
descriptive matter are in all cases to be interpreted as
merely illustrative of the principles of the invention,
rather than as limiting the same in any way, since it is
contemplated that various changes may be made in various
elements to achieve like results without departing from
the spirit of the invention or the scope of the appended
claims.
