close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3083768

код для вставки
April 2, 1963
3,083,763
J. w. BROWN, JR
HEAT EXCHANGER
Filed NOV. 18, 1959
2 Sheets-Sheet 1
83%
/>
W
A2
HTIIIIIVI
I
I
/3
IN VEN TOR.
JOHN w. Bk’o Wu, J]?
BY
.
Beau/Md‘ , 1174mm
Hwaawm (know-(l4
ATTORNEYS
United States Patent O??ce
3,933,763
Patented Apr. 2, 1963
1
2
3,933,763
increased with a view toward adding enough heat to
reduce the viscosity of the liquid, not only are added
HEAT EXQHANGER
John W. Brown, .liz, Lakewood, (Elsie, assignor to llrown
Fintnhe Company, Elyria, Ethic, a corporation of @hio
Filed Nov. 18, 1959, Ser. No. 353,3(l8 '
8 iillairns. (Cl. 165--l5‘9)
This invention relates to heat exchangers.
heating costs involved, but also the liquid in the immedi
ate vicinity of the ?nned tubes may be overheated or
decomposed, with consequent possibilities of clogging the
spaces between the ?ns with solid decomposition products
or even of incurring danger of explosion from gaseous
More par
products of decomposition.
In general, in order to achieve a high rate of heat
ing an outer shell of circular cross section within which 10 transfer in a given length of heat exchanger, it is desir
able that each ?nned tube of the bundle be of the hair
is disposed a bundle of inner tubes having longitudinally
ticularly it relates to heat exchangers of the type embody
extending external heat transfer ?ns. This application
is a continuation-in-part of my copending application
Serial No. 610,339 ?led September 17, 1956, now
abandoned.
In heat exchangers of this type, one of the heat
exchange ?uids ?ows longitudinally within the shell and
outside of the ?nned tubes in the bundle, while the other
heat exchange fluid- ?ows within the tubes, the heat trans
fer ?ns being provided on the tubes to increase the rate
of heat exchange between the ?uids. The purpose of
using a multiplicity of ?nned tubes is to obtain a large
amount of heat exchange capacity in a limited space,
which is particularly important in certain services. For
example, heat exchangers of this type are often used as
tank suction heaters or line heaters for heating heavy
viscous liquids such as oil to reduce their viscosities suf
?ciently to enable them to be pumped from storage tanks
or through pipe lines; in such service it is extremely im
portant that the maximum heat exchange capacity be
obtained in the space available, because of the dil’rlculty
of heating the viscous liquid and the troubles and costs
of pumping it if its viscosity is not su?iciently reduced.
Furthermore, in order to achieve maximum possible
heat transfer between the ?uid within the tubes and the
?uid ?owing along the tubes within the shell, the tubes
must be positioned as close together in the bundle as
possible without intermeshing of the ?ns on adjacent
tubes. While positioning of the tubes in this manner
minimizes the spaces between the tubes through which
fluid might flow without coming into contact with or close
to the ?ns at the same time it gives the bundle a gen
erally polygonal shape transversely of the axes of the
?nned tubes and the shell. When for strength and
economy of manufacture the shell is of circular cross
section as is the almost universal practice, substantial
pin type comprising two straight ?nned tube sections
joined .at one end by a return bend.
‘Furthermore, to
enable the heat exchanger to be easily assembled and
disassembled for inspection, cleaning, or repair, it is
desirable that the straight portions of each hairpin tube
of the bundle be connected at only one end of the bundle
to inlet and outlet means and to the shell, the other end
of the bundle being free of connections to the shell, so
that the bundle of hairpin tubes can be withdrawn or
inserted as a unit from one end of the shell.
The ?nned
tubes themselves within the bundle must be readily acces
sible after disassembly of the heat exchanger, particu
larly if it is used in certain chemical services. The hair
pin tubes also should be capable of moving relatively
to the shell, to permit them to bow or bend along their
length under the influence of heat or to move somewhat
as a result of pulsations of the ?uid in the tubes, thereby
to prevent the development of stresses suf?cient to cause
breakage or leakage of the tubes.
Furthermore, the relatively light gauge heat exchange
?ns which make possible desired heat transfer efficiencies
must not be subjected to striking or cha?ng against each
other or any other part of the heat exchanger during
such movements of the tubes relative to the shell, should
not be subjected to bearing or other pressures su?icient
to damage the ?ns during use, and should be protected
during assembly or disassembly of the heat exchanger.
The solution of these problems is particularly difficult
40 in larger heat exchangers of this type in which the bundle
of ?nned tubes may be twenty feet or more in length.
in such cases there are dangers of excessive bending of
end-supported tubes, as well as damage to the ?ns from
this cause and from the heavy pressure applied to the
?ns by supporting means during use or handling; and
these dangers must be guarded against.
These and other important factors have not been taken
into account in prior attempts to insure that ?uid within
in the absence of the present invention, these wide periph 50 the shell of a heat exchanger will closely contact tubes
in the shell containing another fluid in order to achieve
eral spaces permit a substantial portion of the fluid flow
maximum feasible heat exchange. For example it has
ing outside of the tubes to pass through the shell at such
been heretofore proposed to reduce the bypassing ?ow of
a distance from the ?ns on the tubes that little‘if any
fluids in the wide peripheral spaces between a cylindrical
heat exchange can take place between such fluid and the
shell and a plurality of ?nless, bare heat exchange tubes
?uid flowing within the tubes. This reduces the ef?ciency
arranged within the shell in a bundle of polygonal cross
of the heat exchanger and increases the size and cost of
section, by surrounding the bundle with a housing of
a heat exchanger designed for a given duty. This un
similar cross section, the tubes being ?xed at both ends
desirable bypassing or short circuiting of the spaces
to tube sheets carried by the shell and the housing also
adjacent the ?ns where heat transfer is most effective is
promoted by the surface resistance to fluid ?ow provided 60 being ?xed at both ends to the shell and supported inde
pendently of the tubes. In such prior device, the rela
by the extended heat transfer surfaces of the ?ns. This
tively wide clearances between the housing and the tubes
factor is particularly important in heating highly viscous
permits considerable bypassing or short circuiting of the
liquids in services of the kind described above; the resist
fluid between the tubes and the housing, with a consider~
ances to ?uid flow provided by the surfaces of the ?ns
able loss of heat transfer effectiveness. Since the tubes
are accentuated by the high viscosity of the liquid which
are ?xed at both ends, they are completely restrained
therefore has a pronounced tendency to seek the wider
against movements due to temperature changes or vibra
peripheral passages providing less resistance to flow; but
tions and hence subject to stresses which could cause
because the liquid in such wider peripheral spaces is
breakage or leakage. Gn the other hand, if the tubes
remote from the heat transfer ?ns it cannot be heated
could move, they would contact or chafe against the
sufficiently to reduce its viscosity enough to permit easy
independently supported housing, with consequent dam
?ow. If in an attempt to avoid these problems the
age. Moreover the connections of the tubes and housing
temperature of the fluid in the tubes is substantially
spaces are necessarily left between the polygonal periph
cry of the bundle and the circular interior of the shell.
’
~
3,888,763
3
d.
at both ends to the shell tube in the prior device make
it impossible to readily disassemble such device and hence
it cannot be used effectively in services which require
bundle'of the heat exchanger of FIGURE I removed
from the shell, and with parts broken away.
FIGURE 3 is a transverse sectional view taken along
line 3-—3- of FIGURE 1.
FIGURE 4 is an enlarged sectional view showing the
periodic inspection cleaning or repair. These problems
are accentuated if long tubes are used; added difficulties
result since sagging of such long tubes causes them to
sealing means and means for closing spaces between the
tubes in the bundle; and
come into contact With the independently supported
enclosure, and increases the clearances between the upper
FIGURE 5 is a fragmentary sectional view along line
tubes and the enclosure with a consequent increase in
5——5'- of FIGURE 4 and to the same scale.
the above-described bypassing or short circuiting of ?uid. 10
As shown in FIGURE 1 of the drawings, one preferred
A general object of the present invention is ‘to provide
form of heat exchanger embodying the present inven
heat exchangers which overcome the problems and sat
tion comprises-a cylindrical shell 10 having an open end
isfy the requirements described above, while avoiding the
de?ciencies of prior devices. Another object of the inven
tion is to provide heat exchangers in which the above
describedbypassing or short circuiting of the ?uid ?ow
ing within the heatexchanger shell is substantially elimi
nated, and substantially all of the ?uid is constrained to
?ow along and in close proximity to the ?nned tubes,
and preferably within the spaces between the ?ns. An 20
other object of the invention is to provide a heat ex
changer in which a plurality of ?nned tubes disposed in
an elongated shell of circular cross section are arranged
in a bundle having a polygonal cross section, which is
covered with a helical wrapping, preferably formed of
light gauge sheet metal, closely and ‘tightly engaging the
?ns at the outer periphery of the bundle to constrain the
?uid to ?ow within the wrapping and substantially en
tirely between the ?ns of ‘the tubes to provide increased
heat exchange. It is another object of the present inven
tion to provide such a heat exchanger in which only one
end of the wrapping engages the shell adjacent the inlet
into the shell, and the other end of the wrapping is open,
so that the ?uid passing through the shell is constrained
to ?ow entirely within said wrapping but the spaces be
tween the wrapping and the shell is accessible to ?uid
Within the shell to permit equalization of pressures on
both sides of the wrapping. A further object of the in
vention is to provide such a heat exchanger in which
the ?nned tubes in the bundle are hairpin tubes connected 40
to the shell at only one end of the bundle so that the
bundle of tubes can be inserted or withdrawn as a unit
from one end of the shell while carrying the wrapping,
and the wrapping itself can be easily removed from the
bundle after withdrawal from the shell for inspection,
c-leanini , or repair of the ?nned tubes. A further object
provided with a ?ange 11 and a closed end 12 to which a
?uid connection 13 is secured. Another ?uid connection
14 is made laterally through the wall adjacent the open
end thereof. One of the connections constitutes ‘an inlet
for ?uid to the shell while the other constitutes the out
let. Ordinarily the lateral connection 14 is utilized as
‘the inlet and the end connection 13 is the ‘outlet, but the
connections may be reversed if desired. In either event
the flow of ?uid between the connection 13 and 14 is
longitudinally ‘of the shell 10. The shell is mounted upon
arcuate supporting members 15‘.
Heat exchange is effected by causing the ?uid within
the shell to ?ow ‘over and along a bundle indicated in
general at 16 and made up of a plurality of tubes 17
having straight portions 18 that are provided with par
allel longitudinally extending radial ?ns on the exterior
thereof. In the form of the invention shown in the
drawing, the tubes are in the form of hairpins, the straight
?nned portions 18- being connected by return bends 19,
and the straight portions 18 of tubes 17 in the bundle
being parallel. The ends 21. of the tubes 17 opposite the
return bends project beyond the ?nned portions 18 and
are secured as by rolling to a tube sheet 23‘. The tube
sheet 23 is clamped between the ?ange 11 on the shell
10 and a ?ange 24 on the header 25, appropriate gaskets
or other seals being disposed between the ‘tube sheet and
the ?anges to provide leakproof joints.
The header 25 may be of known design and includes
an inlet pipe 27 which leads to the inlet chamber 28‘ and
‘is used to supply ?uid to the interior of the tubes 17.
The inlet chamber 28 constitutes the upper half of the
space within the header and is separated from the dis
charge chamber 29, which constitutes the lower half of
the space within the header, by means of a partition 31
is to provide a heat exchanger having a. tube assembly,
preferably formed integrally with the header 25 and
which may be of substantial length, comprising a bundle
engaging a sealing gasket 32 ion the surface of tube sheet
of ?nned tubes with separating means inside the bundle
23. A return connection 34 formed in the header 25
preventing intermeshing of the ?ns of the tubes while 50 is in communication with the discharge chamber '29 and
permittingthe tubes to be positioned in close proximity
provides for connection to a return conduit for the ?uid
to each other, and a wrapping closely contacting ?ns of
that has p-assedwthrough the ?nned tubes from the inlet
outer tubes in the bundle to hold the ‘bundle of tubes to
chamber 28 ‘to the discharge chamber 29‘. Heat ex
gether :and cooperate structurally with the ?ns ‘and such
changers of this sort may be used with a wide variety
separating means to increase substantially the strength 55 of ?uids; for example the illustrated heater may be used
of the tube assembly while permitting movements of
to ‘advantage to heat viscous ?uids such as oil passing
the vbundle of tubes relative to the shell in response to
through a pipe line, in which case steam is supplied to the
temperature changes, vibrations, or other causes, suf
conduit 27 and condensate returned to the connection 34.
?cient to prevent ‘the development of harmful stresses.
As shown particularly in FIGURE 3, the ?nned tubes
Another object of the invention is to provide a heat ex 60 in the bundle are preferably disposed as close together
changer having such a wrapping, and also means closing
as possiblein substantially tangential relation to cause the
wider interstices between the ?nned tubes and between
?uid ?owing within the shell and through the bundle on
the tubes and the wrapping to constrain the flow of sub
the exterior of the tubes to pass close enough'to the ex
stantially all ‘?uid into the spaces between the ?ns. An
ternal surfaces of the tubes or to the ?ns to be in good
other object is the provision of heat exchangers having 65 heat exchange relation thereto. Advantageously, the
?nned tubes are kept from intermeshing by separating
factured readily and at reasonable costs.
'
means tangentially contacting ?ns of adjacent tubes in
Further objects and advantages of the invention will
the bundle; in the preferred form such separating means
these advantageous characteristics which can be manu
become apparent from the following description of a
are bands 36 wrapped around the ?ns of individual tubes
preferred form thereof reference being made to the ac 70 and contacting ?ns of adjacent tubes, as described and
companying drawings, in which:
FIGURE 1 is a longitudinal sectional view with parts
broken away showing a preferred form of heat exchanger
embodying my invention. ’
claimed in my prior Patent No. 2,499,901 issued March
7, 1950. It is to be noted that the bands 36 offer sub
stantially no obstruction to the longitudinal ?ow of ?uid
through the bundle and that there are no other supports,
FIGURE 2 illustrates the assembly comprising the tube 75 ba?les or the like in the spaces vbetween the ?ns of the
?nned tubes in the bundle, so that longitudinal ?ow of the
?uid through such spaces is unimpeded, while the tubes
are so closely spaced that little if any transverse ?ow takes
place within the bundle. With the tubes arranged in this
fashion, the cross sectional shape of the bundle is general
ly polygonal, as shown in FIGURE 3; that is, lines
sloped at different angles so that the space 56 between the
conical surfaces 53 and 55 is tapered or wedge-shaped,
being widest at the end nearest the connected end of the
tube bundle. A suitable sealing ring 57 formed of resilient
material, such as an ‘O ring, is disposed in this space be
tangent to the outer ?ns in the bundle would de?ne a
tween these two conical surfaces 53 and 55 of members
51 and 54. It is apparent that the sealing means 50‘ is
polygon. As also shown in FIGURE 3, when the polyg
onal bundle is located within the round cylindrical shell,
such that the parts of it can be easily assembled and dis
assembled when the tube bundle is inserted or withdrawn
substantially wide spaces as indicated at 37, 38, and 39‘
exist between the periphery of the bundle and the in
terior surface of the shell. Fluid ‘?owing through these
spaces would be heated only slightly if at all, by the ?uid
within the finned tubes and yet a large percentage of the
?uid flowing through the shell would flow through these
spaces in a heat exchanger of conventional construction.
According to the present invention, however, the by
passing or short circuiting of the ?uid through the periph
eral spaces between the exterior of the tube bundle and
the interior surface of the shell is eliminated, and sub
stantially all of the ?uid is constrained to ?ow longi
tudinally along and through the tube bundle in close
proximity to the ?nned tubes making up the bundle.
This is accomplished in the preferred form of the inven~
tion shown herein by providing an open ended wrapping
around the exterior of the bundle in the zone of the
?nned portions 18 of the tubes and by causing the ?uid
entering the inlet id to ?ow within the wrapping. The
wrapping preferably is composed of light gauge sheet
metal, although it may be made of any other suitable 30
impermeable material, such as a sheet plastic, that will
withstand the temperatures at which the heat exchanger
operates and which will not be attacked by the ?uid ?ow
ing through the shell. The wrapping material is thin,
?exible and tough enough so that it can be wrapped
tightly around the tube bundle so as to conform to the
polygonal shape thereof, and may be held in place by
one or more straps indicated at 43 and 44 in FIGURES ‘1
and 2. The thickness of the wrapping and the straps is
necessarily somewhat exaggerated in the drawing. Pref
erably a strip 45 of wrapping material is wound helically
around the bundle as shown in the drawings with an over
lapping seam as shown at 46. The seam may be sealed
by welding, brazing, ‘soldering, heat sealing or the like,
depending on the material used; however with a helical
wrapping and an overlapping seam as shown, it is ordi
narily unnecessary to seal the seam, because there is no
substantial pressure difference between the ?uid on the
inside and the ?uid on the outside of the wrapping and
because the direction of the overlap is such that the in 50
ternal edges of the strip face downstream (i.e., away from
the inlet 14 and toward the outlet 13) so that the flow of
fluid tends to draw ?uid into the wrapping rather than
force it out of the wrapping. This type of seam results
when the helical strip is wound from the end of the
bundle adjacent the inlet to the shell toward the end of
the bundle near the outlet from the shell.
from the open end of the shell 10 in assembly or disas
sembly of the heat exchanger. Moreover, the pressure of
the ?uid entering the shell tends to drive the sealing ring
‘57 more tightly into the wedge-shaped space 56 between
members 51 and 54, thus enhances the sealing action.
To aid the wrapping 42 in directing the ?ow of fluid
into the spaces etween the ?ns and prevent bypassing or
short circuiting of such spaces, means may be provided
substantially to ?ll or block other spaces of substantial
width or cross section lying within the enclosure formed
by the wrapping 42-. For example in the illustrated em
bodiment and as shown in FIGURES 3 and 4 the rela
tively wide spaces 61 within the bundle of ?nned tubes
and de?ned by the ?n peripheries of the two innermost
rows or" ?nned tubes in the bundle which are not staggered
relative to each other, are substantially closed by ?ller
means 62; and the spaces 63 of generally triangular cross
section de?ned by the wrapping and the fin peripheries of
the finned tubes at the outer periphery of the bundle are
substantially closed by ?ller means 64. Vfhile these ?ller
means may take various forms and have a variety of
cross sections including those of circular con?guration, it
is most convenient and economical that they be formed of
rods or bars of metal or other suitable materials of sizes
and cross-sectional shapes as will closely ?t, extending
longitudinally through in such spaces as shown.
As is shown to advantage in FIGURES 4 and 5, more
over, t e ?ller bars 62 and 64 are restrained against move
ment longitudinally of the tube bundle 16 by being con—
nected to the member 51 of the sealing means 50. The
end of each of the filler bars 62 adjacent the inlet into the
shell is fixed to a member 65 which may be suitably con
nected, as by welding or bolting, to the member 51. Each
of the ?ller bars 64 at the periphery of the tube bundle
is ?xed to a lug 66 at its end adjacent the shell inlet 14;
such lug extends radially outwardly to member 51 to
which it is connected, as by welding or bolting. The
?ller bars are thus secured against movement longitu
dinally of the ?nned tubes so that the liquid flowing
through the bundle of finned tubes will not force such
?ller bars out of the spaces between the tubes.
It will be evident that with the arrangement described
above, all ?uid entering the shell It) through the conduit
14 is constrained to ?ow within the wrapping 42, and
because of the ?uid flow-directing functions of such
Wrapping and of the filler bars 62, and 64, substantially
all such fluid is constrained to flow within the spaces
between the fins on the ?nned tubes.
in order substantially to prevent fluid from ?owing
The spaces 37, 38, and 39 outside of the periphery
through the spaces 37, 38, and 39 between the exterior of
of the tube bundle are effectively blocked against any
the wrapping 42 and the interior of the shell 16, sealing (iii ?ow of ?uid by the wrapper 42. and the sealing means
means 5% is disposed at one end of the wrapping, pref
5%; wt er spaces within the periphery of the tube bundle,
erably adjacent the inlet for the fluid into the shell which
such as spaces st and 63, re also blocked against any
is the conduit 14- in the embodiment shown.
substantial flow of fluid by the ?ller bars 62 and 64.
The sealing means 5i"? comprises a ring-shaped metal
' However, since the end of the wrapping 42 remote from
member 51 having an interior opening 52 conforming to
sealing means 5% is not connected to the shell, the ?uid
the polygonal shape of the exterior of the wrapping 42,
within the shell ?lls the spaces between the wrapping and
and an external tapered conical surface 53 facing away
the interior of the shell, so that the pressures on the
from the connected end of the tube bundle 16. Member
interior and the exterior of the wrapping are equalized.
51 may be ?xed to the exterior of the wrapping, as by
welding or bolting it. A cooperating annular metal mem 70 Consequently the wrapping can be made of light gauge
material. Since there is no substantial movement of
ber 54- is ?xed to the inner surface of the shell by welding
?uid within the shell on the exterior of the wrapping the
or other suitable means; it has an internal conical surface
presence
of the ?uid in the peripheral spaces outside of
55 facing toward the connected end of tube bundle 16.
the wrapping has negligible effects on the heat exchange
Surface 55 surrounds but is spaced from the conical sur—
capacities of the heat‘ exchanger; in fact the ?uid in these
face 53 of member 51 and the surfaces 53 and ‘55 are
3,083,763
8 .
places acts primarily as an insulator to conserve heat
which would otherwise be, wasted.
1 In order to support the unconnected end of tube ‘bundle
16 within the shell 10 duringoperation, and to prevent
damage to the wrapping 42 when the exchanger is being
assembled or when the tube bundle is being withdrawn
for inspection, cleaning, or repair, I preferably provide
asupporting shoe 67 adjacent the end of the wrapping 42
remote from the sealing means 50. Shoe 67 may be
held in position by being spot welded or otherwise se 10
?nned tubes apart only sufficiently so that their ?ns can
not intermesh or entangle to become damaged or impede
the ?ow of ?uid between the ?ns, while themselves offer
ing little resistance to ?uid ?ow; the tightly wound wrap
ping 42_ in effect holds the entire bundle of ?nned tubes
together in as close relation as possible consistent with
the separating action of the bands 36. This holding
pressure exerted by the wrapper is substantially equally
distributed over the entire length of the tube bundle,
through the outer ?ns of the outer tubes and through
cured to strap 43 and has an arcuate bottom surface 68
contact of the bands 36 with the ?ns of adjacent tubes.
and an upper surface 69 that engages the lower portion
There is no localized pressure whichv can crush, twist or
of the wrapping and distributes the weight of the tube
otherwise damage the ?ns and impede ?uid flow or re
bundle widely over the downwardly extending ?ns. on
duce heat exchanger efficiency. The wrapper 42 and
the tubes at the bottom of‘ the bundle. The shoe thus 15 bands 36 also operate to minimize sagging or deflection.
provides a surface which can be easily slid along the
of the tube bundle as a whole, and to prevent movement
bottom of the interior of the shell when the tube bundle
of the ?nned tubes relative to each other in the bundle
is being inserted into or withdrawn from the shell.
due to individual tube sagging or other reasons, which
The other or connected end of the tube bundle 16 is
could cause damage to the ?ns. This advantage is par
supported by the ends 21 of the tubes 17 which are se 20 ticularly important in larger heat exchangers, some of
cured to the tube sheet 23.
which may be twenty-?ve feet or more in length and
From the foregoing description of a preferred form of
having ?nned tube sections twenty feet long or longer.
the invention it will be evident that I have provided a
Therefore, despite the fact that the ?ns are individually
heat exchanger of the type embodying a shell and a
relatively fragile and the wrapper 42 itself is formed of
bundle of longitudinally ?nned tubes in which the heat 25 such thin, ?exible material that it cannot form an inde
exchange potentials provided ‘by the extended heat trans
fer surfaces of the ?ns are substantially fully utilized and
to a far greater extent than otherwise possible.
Ordinarily, ?uids, and particularly heavy viscous ?uids,
have a tendency to bypass the narrow spaces between
the heat transfer ?ns because the extended heat transfer
surfaces offer higher surface resistance to the ?ow of
?uid than do wider spaces which have less surface area
in relation to volume; hence the ?uid would tend to ?ow
through wider spaces suchas peripheral spaces 37, 38,
and 39 and the’larger intrabundle spaces such as 61 and
63 if they were unblocked, with most passing through
‘spaces 37, 38, and 39 because they are widest. In the
heat exchanger illustrated, however, the wide peripheral
pendent, self-supporting structure, the wrapper 42, bands
36 and ?ns cooperate to utilize the tensile strength of
the wrapper and the considerable aggregate strength of
the ?ns to cause them to act as structural elements pro
viding a. unitary bundle or ?nned tubes having a beam
structure of considerably greater transverse strength than
the total of the individual strengths of the tubes.
The wrapping 42- also protects the relatively fragile ?ns
during handling of the tube bundle in the manufacturing
35 plant, insertionv for assembly of the bundle of tubes into
the shell of the heat exchanger, or withdrawal of the
bundle from the shell for disassembly. The invention
provides particular advantages when employed in heat
exchangers having a bundle of hairpin tubes so designed
spaces are blocked by the sealing means 5!} and the 40 that the tubes can be inserted into or withdrawn from
one end of the shell. Since the wrapping is carried by
14 of the shell is required by the sealing means 50 to
the hairpin tubes and has ?at seams with no projecting
?ow'through the wrapping 42. The wrapping 42 of thin
joints or ?anges, it can be easily moved into or out of
impermeable material closely contacts and bears against
the shell from one end of the shell; during such move
the outer ?ns of the ?nned tubes at the periphery of the
ment, it aids in holding the tube bundle together and
wrapper 42, and all ?uid entering the shell through inlet
bundle and therefore conforms closely to the shape of
provides considerable strength and protection for the tube
the‘bundle; it provides no clearances within the wrapping
bundle, while adding little to the weight of the assembly.
other than the spaces between the ?ns and the openings
Furthermore the wrapper can easily be unwrapped or
resulting from the circular cross sections of the ?nned
removed from. the bundle of tubes after removal from
tubes tangentially arranged relative to the ‘wrapping and 50 the shell to expose the ?nned tubes, if desired. The
to each other. And, as described above, the preferably
easily- disassembled heat exchangers made possible by the
used ?ller bars 62 and 64 substantially close all passages
invention have great utility in services in which‘ they must
through which the ?uid passing within the wrapping could
be periodically taken apart for inspection, cleaning, or
bypass the spaces between the ?ns. Since the Wider
repair, as in services where highly viscous heavy ?uids
spaces outside the periphery and within the periphery of
such as oils, or certain chemicals are heated. The strength
the bundle are thus blocked by the wrapping 42, seal
of tube bundle, ?n protection and other advantages de
ing means 50 and the ?ller bars 62 and 64, substantially
scribed in connection with assembly and disassembly are
all the ?uid flowing through the shell 10 is caused to ?ow
exceptionally important in larger heat exchangers of the
in excellent heat transfer relation through the spaces be
sizes mentioned above.
tween the ?ns of the ?nned tubes. The heat exchange 60
The widely distributed bearing of the wrapper 42
inefficiencies which would result from bypassing or short
along the length of the ?nned tubes also provides other
circuiting of these spaces by the ?uid are eliminated, the
substantial bene?ts in the type of heat exchanger having
effectiveness of the extended heat transfer surfaces of
a bundle of hairpin tubes which is connected at only
the ?ns is substantially fully utilized, and the heat ex
one end of the bundle to the shell. IIn such an exchanger,
change ef?ciency of the heat exchanger is substantially
increased as compared to prior heat exchangers lacking
the present invention.
In addition to the above advantages of directing ?uid
?ow to achieve maximum heat exchange ei?ciency, the
wrapping of the invention provides other important and
unique advantages. Thus the wrapping 42 around the
bundle of ?nned tubes and the bands 36 around indi
vidual ?nned tubes cooperate with the ?nned tubes to
form a strong coherent lightweight tube assembly struc
65 the unconnected end of the bundle must be supported
from. the shell since the connections of the tubes at the
other end of the shell cannot be made strong enough
as a practical‘ matter to support the laterally projecting
hairpin tubes which in certain services may be as much
as twenty feet or more long. Since the wrapping has
such widely distributed bearing over the bundle, support
ing pressure from a supporting member bearing on the
Wrapper near the unconnected end of the tubes is dis
ture; thebands in effect tangentially hold the individual 75 tributed over a substantial‘ area of the bundle of ?nned
tubes. This avoids the possibility of crushing, bending
aces/res
.
b
or otherwise damaging the ?ns in a localized area which
could occur it the supporting member bore directly on
the ?ns.
The wrapping also provides substantial advantages be
cause it does not harmfully restrict necessary movements
of the bundle of ?nned tubes as a whole relative to the
shell. Thus, bending or bowing of the bundle of ?nned
it)
are provided to the ?ns and ?nned tubes during assembly,
disassembly and operation, the durability and life of the
?ns and the heat exchanger as a Whole are greatly in
creased. These advantages are made possible at little
additional cost.
Those skilled in the art will appreciate that the inven
tion may be adapted to other types of heat exchangers
tubes may tend to occur due to heat expansion of the
embodying bundles of longitudinally ?nned tubes, and
and can move with the bundle as a whole, particularly
longitudinally extending, generally radially projecting
that various changes and modi?cations can be made in
metal of the tubes during operation of the heat exchanger;
this tendency is particularly prevalent in heat exchangers 10 the invention without departing from the spirit and scope
thereof. The essential characteristics of the invention
in which the tubes are of the hairpin type and connected
are de?ned in the appended claims.
only at one end of the exchanger. Similarly, vibrations,
I claim:
such as those occurring from ?uid or pump pulsations,
1. A heat exchanger CG; rprising an elongated shell of
tend to cause movement of the tubes relative to the shell.
circular cross section; an inlet adjacent one end of said
If the tubes were completely restrained against such
shell; an outlet adjacent the other end of said shell; a
movements, damaging stresses causing fractures and
bundle of elongated heat exchange tubes within said
leakage could occur. However, since the wrapping is
shell, each of said tubes having a plurality of spaced,
carried by the bundle of ?nned tubes, is of light weight,
when the wrapping is formed of a helical strip of metal
providing some sliding movement of the overlapping
metal edges at the helical seam so that the wrapping as
a whole can de?ect somewhat, the bundle of tubes as a
whole can move sumciently to relieve harmful stresses
?ns thereon, said tubes being positioned in said bundle
so that the peripheries de?ned by the outer edges of the
?ns of said tubes are in substantially tangential, close,
substantially parallel relationship and the outermost edges
of ?ns of outer tubes in said bundle define a bundle
which otherwise could cause damage. Moreover the ?ns 25 periphery which is generally polygonal in cross section
and which causes peripheral spaces to exist between said
cannot be damaged by striking or cha?ng against the
bundle periphery and the interior of said shell; means
wrapping or against the tins of adjacent tubes, since there
for passing ?uid longitudinally inside said ?nned tubes;
is little if any individual movement of the tubes relatively
means for causing ?uid ?owing outside of said tubes
to the wrapper or to each other. Similar advantages
through said shell from said inlet to said outlet to pass
obtain it the tubes tend to de?ect somewhat due to their
in close proximity to said tubes in said bundle and for
weight and length, as often occurs in heat exchangers
having exceptionally long tubes.
preventing said ?uid from ?owing through said periph
Furthermore, such movement or de?ection of the tubes
does not form any wider clearance between the tubes and
ping on said bundle made up of a strip of ?exible, thin,
the wrapper through which the ?uid could bypass the
spaces between the ?ns, because the wrapper is carried
by, tightly encloses, and moves with the tube bundle.
The helical wrapping, and the ?ller bars, which provide
such important advantages may be incorporated into
heat exchangers at low costs Without using special equip
ment, tools or dies. These parts may be made of readily
available materials without high fabrication costs; there
fore it is not necessary to employ pressed or cast parts
which would be excessively costly at the small production
runs obtaining in the heat exchanger ?eld.
Furthermore, the wrapping provides such protection,
strength, and wide distribution of supporting and handling
eral spaces, said means comprising an open ended wrap
impermeable sheet material tightly wound helically
around and conforming to the generally polygonal shape
of said bundle with the helical turns of the strip over
lapping and the internal edges of said turns facing away
from said inlet and toward said outlet, said helically
wound strip engaging and being entirely supported by the
outermost ?ns of the outer tubes of said bundle and
forming with'the tubes in the bundle a beam structure
having greater transverse strength than the. total of the
strengths of the individual tubes in the bundle, said
wrapping alone being incapable of acting as an inde
pendent self-supporting structure; and means connecting
lighter gauge, and hence less expensive, metals than
said wrapping to the interior of said shell to block the
?ow of ?uid through the spaces between the exterior of
said wrapping and the interior of said shell.
2. A heat exchanger comprising an elongated shell of
would be the case in the absence of the wrapping.
The present invention therefore provides heat ex
circular cross section; a shell inlet adjacent one end of
said shell; a shell outlet adjacent the other end of said
loads on the ?nned tubes as described above that the
?ns and even the tubes themselves may be made of
changers in which substantially all of the ?uid ?owing
shell; a bundle of elongated hairpin-shaped heat exchange
stantially fully utilizing the heat transfer potentialities
of the ?ns and making possible exceptionally high heat
tudinally extending, generally radially projecting ?ns
tubes within said shell, each of said tubes comprising
through a shell tube is caused to pass through the spaces
between the ?ns of the bundle of ?nned tubes, thus sub 55 two ?nned sections having a plurality of spaced longi
thereon, said tubes being positioned in said bundle so that
the peripheries de?ned by the outer edges of said ?ns are
transfer e?ciencies. Moreover such a heat exchanger
in substantially tangential, close, substantially parallel
may be of the type in which hairpin ?nned tubes are
connected at one end only to the shell, so that the ex 60 relationship and the outermost edges of ?ns of outer tubes
in said bundle de?ne a bundle periphery which is gen
changer can be readily disassembled for inspection, clean
erally polygonal in cross section and which causes periph
ing or repair by withdrawing from one end of the shell
eral spaces to exist between said bundle periphery and
the bundle of ?nned tubes carrying the wrapper, and then
the interior of said shell; inlet and outlet means located
stripping the wrapper from the tubes; this is extremely
important when the heat exchanger is used in services 65 at one end only of said shell for passing ?uid longitudi
nally through said ?nned tubes; means for causing ?uid
where it must be periodically checked. Since there is no
?owing outside of said tubes through said shell from said
?uid passing through spaces at a considerable distance
shell inlet to said shell outlet to pass in close proximity
from the ?ns there is no need to heat such ?uid by the
to said tubes in said bundle and for preventing said fluid
use of tube temperatures so high as to cause deteriora
tion to or decomposition of the fluid adjacent the ?ns, or 70 from ?owing through said peripheral spaces, said means
comprising an open ended wrapping on said bundle made
damage to the heat exchanger itself.
up of a strip of ?exible thin impermeable sheet material
Because the wrapper cooperates to form a strong struc
tightly Wound helically around and conforming to the gen
ural assembly of tubes, which however, can move or
erally polygonal shape of said bundle with the helical turns
de?ect as necessary to relieve temperature, vibratory or
other stresses, and since adequate support and protection 75 of the strip ovelapping and the internal edges of said turns
11
3,083,763.
facing away from said shell inlet and toward said shell,
outlet, said helically wound strip engaging and being en
tirely supported by the ‘outermost ?ns of the outer tubes
of said bundle and cooperating with said tubes in said
bundle to form a beam structure having greater transverse
strength than the total of the strengths of the individual
tubes in the bundle, said wrapping along being incapable
12
tionship and the outermost edges of ?ns of outer tubes
in said bundle de?ne a bundle periphery which is gen
erally polygonal in cross section and which causes periph
eral spaces to exist between said bundle periphery and
the interior of said shell; separating means engaging the
outer edges of ?ns of adjacent tubes within said bundle
to prevent intermeshing of the ?ns of adjacent tubes
of acting as an independent self-supporting structure; and
while leaving unobstructed the spaces between the ?ns;
means connecting said wrapping to the interior of said
inlet and outlet means located at one end only of said
shell to block the. ?ow of ?uid through the spaces be 1,0 shell for passing ?uid longitudinally through said ?nned
tween the exterior of said wrapping and the interior of
tubes; means for causing ?uid ?owing outside of said
said shell.
tubes through said shell from said shell inlet to said shell
3. A heat exchanger comprising an elongated shell of
outlet to pass, in close proximity to said tubes in said
circular cross section; an inlet adjacent one end of said
bundle and for preventing said ?uid from ?owing through
shell; an outlet adjacent the other end of said shell; a 15 said peripheral spaces, said means comprising an open
bundle of elongated heat exchange tubes within said shell,
ended wrapping on said bundle made up of a strip of
each of said tubes having a plurality of spaced longi
tudinally extending, generally radially projecting ?ns
thereon, said tubes being positioned in said bundle so
that theperipheries de?ned by the outer edges of said
?ns are in substantially tangential, close, substantially
parallel relationship and the outermost edges of ?ns of
?exible, thin, impermeable, sheet material partly wound’
helically around and conforming to the generally polyg
onal shape of said bundle with the helical turns of the
strip overlapping and the internal edges of saidturns fac
ing away from said shell inlet and toward said shell out
let, said helically wound strip engaging and being en
outer tubes in said bundle de?ne a bundle periphery which
tirely supported by the outermost ?ns of the outer tubes
is generally polygonal in cross section and which causes
peripheral spaces to exist between the exterior periphery 25 of said bundle, said wrapping alone being incapable of
acting as an independent self-supporting structure; band
of said bundle and the interior of said shell; separating
means
encircling said helically wound wrapping and
means engaging the outer edges of ?ns of adjacent tubes
holding it tightly in place on said bundle, said band means,
within said bundle to prevent intermeshing of the ?ns
said wrapping, and said separating means cooperating
of adjacent tubes while leaving unobstructed the spaces
with
tubes in the bundle to form a beam structure
between the ?ns; means for passing ?uid longitudinally 30 havingthegreater
strength than the total of the strengths of
inside said ?nned tubes; means for causing ?uid ?owing
the individual tubes in the bundle; andmeans connecting
outside of said tubes through said shell from said inlet
said wrapping to the interior of said shell to block the
‘to said outlet to pass in close proximity to said tubes in
?ow of ?uid through the spaces between the exterior of
‘said bundle and for preventing said ?uid from ?owing
said wrapping and the interior of said shell.
through said peripheral spaces, said means comprising
5. The apparatus of claim 1 comprising ?ller means
an open ended wrapping on said bundle made up of a
within said wrapping, contacting the outer edges of the
strip of flexible, thin, impermeable, sheet material tightly
?ns of and leaving unobstructed the spaces between ?ns,
wound helically around. and conforming to the generally
to block spaces between the peripheries de?ned by the
polygonal shape of said bundle with the helical turns of
the strip overlapping and the internal edges of said turns 40 outer edges of ?ns of adjacent ?nned tubes.
6. The apparatus of claim 5 in which said ?ller means
facing away from said shell inlet and toward said shell
block spaces between the interior surface of the wrapping
outlet, said helically wound strip engaging and being en
and the peripheries de?ned by the outermost edges of
tirely supported by the outermost ?ns of the outer tubes
adjacent outer ?nned tubes.
of said bundle, said wrapping alone being incapable of
7. The apparatus of claim 5 in which said ?ller means
acting as an independent self-supporting structure; band 45
block the spaces between the peripheries de?ned by the
means. encircling said helically wound wrapping and hold
outer edges of adjacent ?nned tubes within said bundle.
ing it tightly in place on said bundle, said band means,
8; The apparatus of claim 5 in which said ?ller means
said'wrapping, and said separating means cooperating
block spaces between the inner surface of said wrapping
with the tubes in the bundle to form a beam structure
having- greater transverse strength than the total of the 50 and the peripheries de?ned by the outer edges of adjacent
outer ?nned tubes, and also block spaces between the
strengths of the, individual, tubes in the bundle; and means
peripheries de?ned by the outer edges of adjacent ?nned
connectingsaid wrapping to. the interior of said. shell to
tubes within said bundle.
7 block the flow of ?uid through the spaces between the
exterior of said wrapping and the interior of said shell.
References Cited in the ?le of this patent
4-. A heat exchanger comprising an elongated shell of 55
UNITED STATES PATENTS
circular cross section; a shell inlet adjacent one end of
said shell; a shell outlet adjacent the other end of said
1,669,291
Dean ________________ __ May 8, 1928
shell; a bundle of elongated hairpin-shaped heat exchange
1,790,151
How _____________ __V_ Jan. 27, 1931
tubes within said shell, each of said tubes comprising
1,995,407
Walker _____________ __ Mar. 26, 1935
two ?nned sections having a plurality of spaced, longi 60 2,183,160
Coulter et a1 __________ __ Dec. 12, 1939
tudinally extending, generally radially projecting ?ns
thereon, said tubes being positioned in said bundle so
that the peripheries de?ned by the outer edges of the
?ns are in substantially tangential, close, parallel rela
2,346,104
2,499,901
2,520,755
2,910,275
Gunter ______________ __ Apr. 4,
Brown _______________ __ Mar. 7,
Brown ______________ __ Aug.r29,
Munro _____________ __ Oct. 27,
1944
1950‘
1950'
1959
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 438 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа