Note: Descriptions are shown in the official language in which they were submitted.
104265~
me present invention relates to improvements in heat tr s fer
apparatus, e.g. cylindrical, rotatable heat tr s fer drums. ~ore particu-
larly, the present invention relates to such heat transfer drums which are
capable of naintaining substantialiy uniform temperatures about their en~;re
surface and are of relatively simple, inexpensive construction.
The use of cylindrical drums which employ various heat transfer
media to heat their outer surfaces, and the use of these drums in various
processes requiring such heat to be applied to various materials, e.g.
textile web materials, disposed on the drum surface, is well known. Gener-
ally, these cylindrical rotatable heat tr s fer drums have employed various
heat transfer media, including steam and certain hydrocarbon liquids. For t
example, it has been known to supply steam to the interior of such cylindri-
cal heat transfer drums in order to heat the outer surface thereof. Thus,
in U.S. Patent No. 2,932,091 issued to G.D. Day on April 12, 1960
such a rotatable drum, used for drying purposes, is disclosed. The appara-
- tus there taught includes a central hollow thick walled pipe for the sup-
ply of steam to radially extending distributors, and then to a large
plurality of parallelly spaced tubes lying about the inner periphery of
the drum itself, and then to a seoond set of radial angularly spaced spokes
or tubes at the opposite end of said drum for return of the steam. The use
of such an apparatus, however, requires various c3ndensate headers in order
to prevent obstruction of the steam passage by condensate forming within
the parallelly spaced tubes, and
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thus disturbing the heat transfer process. It is thus also necessary to
impart the steam itself through these tubes at high velocities, in order to
hold dcwn condensation, and to addition~lly scavenge condensate which has
formed therein. The use of steam has also raised other difficulties, -~ '
including problems of rust and corrosion, as w~ll as the necessity to em-
ploy massive heavy equipment.
In an attempt to solve these problems, the use of various fluid
media, such as hydrocarbons, has been suggested. For example, U.S. Patent
No. 3,228,462 issued to H.C. Smith on January 11, 1966 teaches such a heat
exchange apparatus, or cylindrical drum, which utilizes such fluids as a
heat transfer media for heating the outer cylindrical surface thereof.
Such patent teaches concentrically disposed inner and outer shells which are ~r
separated by parallel partitions, for the supply of such a medium to the
surface of the cylindrical drum for allegedly uniform heating thereof.
Such patent also provides independent, internested, labyrinthine flow chan- !
nels which extend around the periphery of the drum, and thus cause the
heat transfer medium to flcw in opposite directions through these channels,
each such flow channel beginning at one end of the drum, and ending at the
other. m us, while such patent attempts to place adjacent each other hotter
and ccoler legs in order to attempt to equalize the surface temperature of
the outer shell, the apparatus taught includes all feed means for hot heat
transfer fluid at one end of the drum, and all return means for cool heat
transfer fluid at the other. In addition, use of such m~lti-path labyrinth-
ine channels, even in large numbers, requires a relatively long flow path
for the medium within each such flow channel, thus permitting
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substantial cooling of this medium during its flow therethrough.
This, in turn, requires the excessive heating of the heat
transfer media prior to its entrance into any given flow channel,
According to a broad aspect of the present
invention, apparatus is provided for uniformly heating materials,
such apparatus comprising. concentric inner and outer shells
defining an annular flow space therebetween; closing means
connecting the opposite ends of the inner and outer shells;
longitudinally extending portions extending between the inner
and outer shells and forming a plurality of longitudinally
extending compartments within the flow space; longitudinally
extending baffles extending between the inner and outer shells
for a portion of the length of the compartments, so that an
approximately U-shaped flow path is formed within each of
the compartments, the approximately U-shaped flow paths each
including only two-legs consisting of an entrance leg and an
exit leg, the legs being circumferentially arranged with
respect to each other; feed means for supplying a heat - transfer r
fluid to the entrance leg of each of such approximately U-shaped
flaw paths; a return means for withdrawing a heat-transfer
fluid from said exit leg of each of such approximately U-shaped
flow paths; a centrally-disposed concentric feed passage adapted
to be connected to a source of heat transfer fluid, said
central feed passage communicating with said feed means and
said return means; and such return means including an annular
return plenum disposed beneath said inner sheli and communicating
with said exit legs of said approximately U-shaped flow paths,
and at least one radially-extending return channel communicating
with said central feed passage and with said annular return
plenum for removing heat-transfer fluid from said annular return
plenum.
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104Z658
By one variant, ~he apparatus includes
dividing means within the central feed passage, for separating
the feed means from the return means.
By a variation, the apparatus includes suppor~ _
struts extending from the central feed passage to the closing
means.
By another variation, the closing means may be
transverse end walls and preferably where such transverse
end walls extend from the central feed passage to the outer
shell
By another variant, the annular return plenum
communicates with the exit legs by means of exit apertures in
the inner shell.
By one variation thereof, the apparatus includes
a plurality of such exit apertures disposed in a circular path
along the surface of the inner shell.
By another variant, the apparatus includes at
least one return orifice communicating with the radially
- extending return channel and with the annular plenum, for
removing heat-transfer fluid from the annular plenum. E.
By a variation, the apparatus includes a
plurality of such radially extending return channels, and
preferably where such radially extending return channels are
disposed at approximately 90 with respect to each other.
By another variant, the feed-means includes:
an annular feed plenum disposed beneath the inner shell and
communicating with the entrance legs of the approximately U-
shaped flow paths; and at least one radially extending feed
channel communicating with the feed passage and with the
annular feed plenum, for supplying heat-transfer fluid to the
annular feed plenum.
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10426S8
By a variation tl~ereof, the apparatus includes
a plurality of radial feed distributors connecting the annular
feed plenum to the entrance legs of each of such approximately .-
U-shaped flow paths.
By another variation, the radial feed
distributors communicate with the entrance legs by means
of entrance apertures in the inner shell.
By still another variation, the apparatus
includes a plurality of such entrance apertures disposed in
a circular path along the surface of said inner shell.
By yet another variation, the apparatus includes
a plurality of such radially extending feed channels which
are disposed at approximately 90 with respect to each other.
By still another variation, the closing means
comprises transverse end walls and preferably where such
transverse end walls extend from the central feed passage to
the outer shell.
By another variation, the annular return plenum
is disposed between the annular feed plenum and the inner
shell.
By another variation, the apparatus includes a
plurality of radial feed distributors connecting the annular
feed plenum to the entrance legs of each of such approximately
U-shaped flow paths, the radial feed distributors passing
through the annular return plenum, and preferably where such
feed distributors communicate with the entrance legs by means
of entrance apertures in the inner shell, and the annular r
return plenum communicates with the exit legs by means of exit
apertures in the inner shell.
By still another variation, the apparatus
includes a plurality of alternating entrance apertures and
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- 104Z658
exit apertures, disposed in a circular path along the surface
of the inner shell. r
By yet another variation, the apparatus
includes a plurality of such radially extending feed channels,
and a plurality of such radially extending return channels,
especially where the radially extending feed channels are
disposed at approximately 90 with respect to each other,
and wherein the radially extending return channels are
disposed at approximately 90 with respect to each other.
By another variation, the apparatus includes
dividing means within the central feed passage, for separating
the feed means from said return means.
By another aspect of this inventian, apparatus - r
is provided for: concentric inner and outer shells defining
an annular flow space therebetween; closing means communicating
with the inner and outer shells; barrier means positioned within
the annular flow space for establishing a plurality of flow paths
having entrance and exit legs; feed means for supplying a heat- ~-
transfer fluid to the entrance legs; return means for withdrawing !-
a heat-transfer fluid from the exit legs; a centrally disposed
concentric fluid passage adapted to be connected to a source
of heat-transfer fluid, the central feed passage communicating
with the feed means and the return means; the feed means includes
an annular feed plenum disposed beneath the inner shell and
- communicating with the entrance legs, and at least one radially
extending feed channel communicating with the central feed t
passage and with the annular feed plenum, for supplying heat-
transfer fluid to the annular feed plenum; and the return means
includes an annular return plenum disposed beneath the inner
shell and communicating with the exit legs, and at least one
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104Z65~3
radially extending return channel communicating with the
central feed passage and with the annular return plenum,
for removing heat-transfer fluid from the annular return
plenum.
By a variant thereof, the apparatus includes
a plurality of radial feed distributors communicating with the
entrance legs and with the annular feed plenum, for supplying
heat-transfer fluid to said entrance legs.
Figure 1 is a perspective view of the heat
transfer apparatus of an aspect of the present invention;
Figure 2 is a partial sectional longitudinal
view of the feed wall end of an aspect of the present
apparatus, including feed and return means;
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Figure 3 appearing on the same sheet of drawing as Figure 1 is a
partial sectional transverse view taken along line 3-3 of Figure 2 showing
the radial ~eed channels, and feed and return plenums, of an aspect of this
invention;
Figure 4 is a disassembled, partial perspective view of the annur
lar feed and return plenums and flow paths of an aspect of the present in- -
vention;
Figure 5 is a development view of the approxim~tely U-shaped
flow paths of an aspect of the present invention; and
Figure 6 is a partial sectional longitu~inal view taken along
line 6-6 of Figure 2, showing the radial feed distributors and return ori-
fices of an aspect of the present invention. :
Referring to the drawings, there is shown a cylindrical, rotata-
ble, heat transfer drum, generally designated 1. The drum includes concen-
tric inner and outer shells, 11 and 4, respectively, which define an annu-
lar flow space 12. The construction of the outer shell 4 should be of a
heat conductive material, e.g. cast iron or steel. These concen~ric inner
and outer shells terminate at tw~ transverse faces 2 and 3 which include
annular plates 39 and 38 which connect the ends of the inner and outer
shells and seal the ends of the annular flow space 12. A central conduit
or feed passage 6 passes through face 3 and is journaled in concentric
bearings 7 and 8 (most clearly shown in Figure 1). The opposite face 2 in-
cludes a support roller 9 mounted in a ooncentric bearing 10. A concentric
return pipe S disposed within the central feed passage 6 is employed for
the withdrawal of the h~at transfer medium after use. The central feed
passage 6 extends only a short distance within the drum past the feed face 3
terminating at a bulkhead 44. Details of this e:bodiment are provided
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below. If desired, the bulkhead 44 could be removed, return
pipe 5 could be closed, and support roller 9 could be
constructed in a hollow tubular fashion to permit the return
fluid to exit through face 2.
The faces 3 and 2, respectively, include support
struts 40 which radiate from the central feed passage 6
outwardly to the annular plates 38 and 39, respectively.
These struts, while having other functions to be discussed
below, also help to maintain the cylindrical shape of the
drum even when it is subjected to considerable external
pressure.
The central feed passage 6 contains radial feed
openings 37 (Figure 2) connecting it with radially extending
feed channels 19 which provide for the distribution of the
heat transfer medium outwardly from central feed passage 6.
The support struts 40 may act as one wall of the radial feed
channels 19. Preferably, there will be four such radially
extending feed channels 19 disposed at approximately
90 with respect to each other and forming spokes for
the transmission of the heat transfer medium from the central
feed passage 6 outwardly towards the annular flow space 12.
Referring to Figure 4, each radially extending feed
channel 19 terminates at an annular feed plenum 22 and
communicates with therewith through openings 21. Between the
annular feed plenum 22 and the concentric inner shell 11 is
an annùlar return plenum 26. To provide for the flow of
fresh, hot oil from the annular feed plenum 22 to the annular
flow space 12 between the inner and outer shells 11 and 14,
respectively, there are provided radial feed distributors 24.
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The radial feed distributors 24 pass through the annular return
plenum 26 and are connected at one end to the annular feed
plenum 22 through openings 23, and at the opposite end to
the concentric inner shell 11 through entrance apertures
25. There is therefore no contact or leakage between fresh
hot feed oil passing through these radial feed distributors
24 and oil within the annular return plenum 26 which, as
discussed below, has already been used to heat the outer
shell 4 and has thus cooled somewhat.
Referring to Figure 5, the entrance aperture
25 in each radial feed distributor 24 permits the passage of
heat transfer media into the annular flow space 12 between
the inner and outer shells 11 and 14, respectively. The
annular flow space 12 is divided into longitudinal arcuate
compartments by partitions 30 which extend between inner
and outer shells 11 and 4 and from the annular plates 38
and 39. One entrance aperture 25 is provided for
passage of heat transfer media into each such longitudinally
extending compartment formed by two adjacent longitudinal
partitions 30. Between each pair of longitudinal partitions
30 is provided a longitudinally extending baffle 31 which
extends between the inner and outer shells, 11 and 4,
but only for a portion of the length of the longitudinally
extending compartments, and terminates a short distance
from the end face 2. Substantially U-shaped flow paths are
thereby provided within each longitudinally extending
compartment thus permitting the flow of hot heat transfer
fluid therethrough as shown by the arrows in Figure 5.
Bach such substantially U-~haped flow path includes an entrance
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leg 45 and an exit leg 46, the entrance leg 45 of each such flow
path being connected to the radial feed distributor 24 through
entrance aperture 25, while the exit leg 46 of each such
flow path is connected to the annular return plenum 26
through exit aperture 32.
As can best be seen from Figure 2, the annular return
plenum 26 is of a shape substantially the same as the
annular feed plenum 22 but is of a size extending longitudinally
from the feed face 3 a greater distance than does the annular
feed plenum 22. There are provided in the annular return
plenum 26 return orifices 27 which communicate with radially
extending return channels 20. The return channels 20 are
connected to the central feed passage 6 through radial return
openings 28. Preferably, there will be four approximately
: radially extending retur~ channels 20, again forming spokes
radiating from the central feed conduit 6, and they will be
disposed at approximately 90 with respect to each other.
Angular disposition of these return channels 20 is preferred
in order to assure that each such approximately radially
extending return channel 20 is connected to the central
feed pas-~age 6 at a point substantially downstream from the
radial feed openings 37 which connect with the radially
extending feed channels 19.
Within the central feed passage 6 between the
radial feed openings 37 and the radial return openings
28 there is provided an internally threaded annular spacer
13 (the threads being designated 14) which receives an
externally threaded return pipe 5 to form coaxial return
passage for heat transfer media being withdrawn from
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the drum. All heat transfer media flowing into the annular
space between the return pipe 5 and the central feed passage
6 will flow outwardly through the radial openings 37.
The heat transfer medium, upon return, will again enter the
central feed passage 6 at a point 17 downstream therefrom,
upon passing through the radial return openings 28, and
will then be withdrawn through return pipe 5.
The drum is also provided with spaced radially
extending struts 18 formed as spokes radiating from the
central feed passage 6 to provide additional support for
the inner and outer shells of the drum, and to further
withstand external pressure exerted thereon.
Referring to Figure 2, heat transfer media
entering the drum through the annular space between central
feed passage 6 and return pipe 5 will flow through the
annular flow space 12 formed between the inner and outer shells,
11 and 4, respectively, in a manner so as to achieve substan-
: tially uniform heating of the external or outer shell 4.
That is, the fresh, hot, heat transfer medium will pass
through the annular space formed in the central, coaxialfeed passage 6 by the return pipe 5, and enter the
drum 1. All of this fresh, hot oil will then pass through four
radial feed openings 37 extending through the central feed
passage 6 into radially extending feed channels 19 and
then through openings 21 into annular feed plenum 22.
The fre~h heat transfer medium passing through openings 21
is then distributed to each substantially U-shaped flow
path in the annular flow space 12 formed between inner
and outer shells 11 and 4, respectively, by passing through
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openings 23, radial feed distributors 24, and entrance apertures
25 into the annular flow space 12. The hot oil passing
through each entrance aperture 25 will then travel through
a substantially U-shaped flow path between the inner and
outer shells formed by longitudinally extending partitions
30 and baffles 31. After traveling through such a flow
path from the feed face 3 along the periphery of the drum
along entrance leg 45 to the return face 2, around the baffle
31, and similarly along return leg 46, back to the feed face
3, the oil will then pass through exit aperture 32. The oil
entering each substantially U-shaped flow path through successive
entrance apertures 25 will thus be fresh, hot oil, and no oil
will travel through more than one such substantially U-shaped
flow path prior to returning through exit apertures 32, for
withdrawal or return. In addition, since the oil exits
at the same side of the drum as it enters, the average
temperature along the length of each compartment will be
substantially uniform.
The return of the heat transfer media will then be
accomplished by its flow through exit apertures 32 into the
annular return plenum 26. The oil in the annular return
plenum, while still relatively hot, will be cooler than the
fresh, hot oil passing through the radial feed distributors
24, which extend through the annular return plenum 26.
The cooling of the fresh, hot oil is thus kept to an absolute
minimum, only a small degree of heat transfer occurring
through the walls of these relatively short radial feed
di~tributors 24. The heat trànsfer medium then passes
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1~42658
through openings 27 into each angularly radially extending return channel
20, and through radial return openings 28, into central feed passage 6, at
a point 17 downstream, with respect to the feed face 3, from the threaded
annular spacer 13. The heat transfer medium or hot oil, now som~what oooled
will then flow through return pipe 5, prevented from further flow longitud-
inally through the drum by the presence of bulkhead 44, for withdrawal from .
the drum, to be either discarded, used for other purposes, or reheated and
recirculated through the drum.
i.
