TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger. More specifically, the present
invention relates to a heat exchanger such as a heater or a cooler capable of performing
low flow processing of a fluid to be processed, especially, for the use of chemical
experiments.
RELATED ART
[0002] Examples of performance generally required for the heat exchanger include heat exchanging
performance, corrosion resistance, pressure tightness, robustness, cleaning properties,
and downsizing. The heat exchanger also requires low cost production thereof. A multipipe
heat exchanger, a double-pipe heat exchanger, a coiled heat exchanger, a plate heat
exchanger, and the like are mainly used as the conventional heat exchanger. Such heat
exchangers, however, have the complex structures or have difficulties in downsizing,
is costly, and low cleaning properties. Especially, examples of the heat exchanger
to be used in low flow processing, more specifically, in chemical experiments generally
include a glass coil type heat exchanger and a glass double-pipe heat exchanger. In
this case, the good heat exchanging performance is not expected because of low thermal
conductivity of the glass itself. However, a large effort is required in cleaning
the processed product adhering to a coil, or a perfect cleaning cannot be realized
in some cases. As a result, many heat exchangers must be prepared, which is costly.
Further, there is a high breakage risk. More specifically, in a case where a harmful
processed product is passed, security measures therefore will also be costly.
[0003] As disclosed in Patent Document 1, conventionally known is a heat exchanger including
a coiled heat-transfer tube placed in a space defined between an inner tube and an
outer tube, wherein an inside space of the heat-transfer tube is used as one of flow
paths, a coiled space between coiled sections of the heat-transfer tube in the space
is used as the other flow path, and wherein an efficient heat exchange is achieved
between one fluid and the other fluid.
However, in the heat exchanger disclosed in Patent Document 1, the heat-transfer tube
is not fixed to either one of an outer peripheral surface of the inner tube or an
inner peripheral surface of the outer tube but the heat-transfer tube is only naturally
mounted. Therefore, in a case of a high-viscosity fluid, the heat-transfer tube expands
or contracts due to a flow resistance, which may cause, for example, pitches between
coiled sections to be non-uniform and partially narrower or tighter.
[0004] In consideration of production and disassembly of the heat exchanger of Patent Document
1, in a case of attachment and detachment of the coiled heat-transfer tube in the
space defined between the inner tube and the outer tube, if a clearance between the
heat-transfer tube, and the inner tube and the outer tube is increased, the attachment
and the detachment of the coiled heat-transfer tube becomes easier. However, the coiled
heat-transfer tube becomes freely movable in the space and thus a problem due to the
expansion and contraction of the heat-transfer tube may arise. On the other hand,
if the clearance is eliminated, the attachment and detachment of the heat-transfer
tube will be difficult.
Related Art Document
Patent Document
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0006] In view of the above, the present invention is to improve one type of heat exchangers,
which includes a coiled heat-transfer tube placed in a space defined between an inner
tube and an outer tube. An inside space of the heat-transfer tube is used as one of
flow paths, and a coiled space defined between coiled sections of the heat-transfer
tube in the space is used as the other flow path. Heat is exchanged between one fluid
and the other fluid. More specifically, a purpose of the present invention is to provide
a heat exchanger to/from which the heat-transfer tube can be attached or detached
with ease. Further, another purpose of the present invention is to provide a heat
exchanger capable of controlling a variation of the flow path area caused by a deformation
of the heat-transfer tube due to a flow resistance. The present invention is directed
to provide the heat exchanger that can achieve either one of the above described purposes.
A more specific purpose of the present invention is to provide a heat exchanger that
is small, has a good heat exchange property, and can perform low flow processing in
which a fluid to be processed can be passed, especially, in various chemical experiments,
with a cost less than those of the conventional heat exchangers.
MEANS FOR SOLVING THE PROBLEM
[0007] To solve the above problems, the invention recited in Claim 1 provides a heat exchanger.
The heat exchanger includes a coiled heat-transfer tube 1 placed in a space 7 defined
between an inner tube 5 and an outer tube 6. An inside space of the heat-transfer
tube 1 is used as one of flow paths, and a coiled space 4 between coiled sections
of the heat-transfer tube 1 in the space 7 is used as the other flow path. Heat is
exchanged between one fluid and the other fluid. The heat exchanger also includes
a tensioning mechanism for keeping an expansion or contraction force for expanding
or contracting a diameter of the coiled heat-transfer tube 1 than a diameter the heat-transfer
tube 1 naturally has. The heat is exchanged between one fluid and the other fluid
while the expansion and contraction force is applied to the heat-transfer tube 1 by
the tensioning mechanism.
The invention recited in Claim 2 provides the heat exchanger of Claim 1, wherein the
heat-transfer tube 1 may not be fixed either one of an outer peripheral surface of
the inner tube 5 or an inner peripheral surface of the outer tube 6, and the tensioning
mechanism may expand or contract a diameter of the coiled heat-transfer tube 1 than
a diameter the tube naturally has, thereby bringing the heat-transfer tube 1 into
close contact with or pressure contact against the inner tube 5 or the outer tube
6.
The invention recited in Claim 3 provides the heat exchanger of Claim 1 or 2, wherein
a load in a coil axis direction applied may be equal to or less than 10 kg when the
heat-transfer tube 1 varies a length of the coil in the coil axis direction by 10%
in comparison with the length of the tube as it naturally has.
The invention recited in Claim 4 provides the heat exchanger of Claim 3, wherein the
heat-transfer tube 1 may be made of a material selected from the group consisting
of metals such as stainless steel, hastelloy, inconel, titanium, copper, and nickel;
acrylic resins such as ABS, polyethylene, polypropylene, and PMMA; fluorine based
resins such as polycarbonate, PTFE, and PFA; and an epoxy resin.
The invention recited in Claim 5 provides the heat exchanger of Claim 4, wherein an
outer diameter of the heat-transfer tube 1 is equal to or less than 28 mm.
The invention recited in Claim 6 provides a heat exchanger. The heat exchanger includes
a coiled heat-transfer tube 1 placed in a space 7 defined between an inner tube 5
and an outer tube 6. An inside space of the heat-transfer tube 1 is used as one of
flow paths, and a coiled space 4 between coiled sections of the heat-transfer tube
1 in the space 7 is used as the other flow path. Heat is exchanged between one fluid
and the other fluid. In the heat exchanger, the coiled heat-transfer tube 1 is elastically
deformed from its natural state so as to be brought into close contact with or pressure
contact against the inner tube 5 or the outer tube 6 and the heat is exchanged between
one fluid and the other fluid while the heat-transfer tube 1 is elastically deformed.
EFFECT OF THE INVENTION
[0008] The heat exchanger according to the present invention keeps a state that the expansion
or contraction force is applied to the heat-transfer tube 1 by the tensioning mechanism
in use, i.e., at least during the heat exchange. Therefore, the heat-transfer tube
always receives the force and thus a deformation of the heat-transfer tube due to
the flow resistance hardly occurs even if the heat-transfer tube does not contact
the inner tube 5 or the outer tube 6. Therefore, a non-uniform deformation of the
coiled heat-transfer tube 1 can be reduced. More desirably, even if the heat-transfer
tube 1 is not fixed to either one of the outer peripheral surface of the inner tube
5 and the inner peripheral surface of the outer tube 6, the deformation occurs less
by bringing the heat-transfer tube 1 to close contact with or pressure contact against
the inner tube 5 or the outer tube 6 by an action of the tensioning mechanism.
Another operation and effect of the heat exchanger according to the present invention
is to make the coiled heat-transfer tube 1 be easily attached or detached. More specifically,
the heat-transfer tube 1 is placed freely with a suitable clearance defined between
the inner tube 5 and the outer tube 6. Then, the heat-transfer tube 1 is placed in
a tensed state to generate the expansion and contraction force to be brought into
contact with either one of the inner tube 5 or the outer tube 6. The expansion and
contraction force is then kept by the tensioning mechanism, thereby keeping the contacting
state. Upon disassembly and the like, the expansion or contraction force is released
to allow the heat-transfer tube to be detached with ease. Alternatively, the heat-transfer
tube is placed in a pressure contact state by applying the expansion or contraction
force after it is attached without the clearance (i.e., in the contacting state).
Then, the pressure contact state is kept by the tensioning mechanism. Upon disassembly,
the expansion or contraction force is released to allow the heat-transfer tube to
be detached relatively easier.
More specifically, in addition to an effective heat exchange, the heat-transfer tube
can be replaced easily even when a clogging or adhesion occurs in the heat-transfer
tube. Therefore, disposal of or expensive cleaning the heat exchanger itself is no
longer necessary as it is required in the conventional heat exchangers. Further, an
occurrence of the expansion or contraction of the heat-transfer tube due to a flow
of heating medium can be avoided. Still further, since the structure can be simplified
in comparison with the conventional ones, manufacturing steps can be reduced. As a
result, the heat exchanger can be provided with lower cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
Fig. 1(A) illustrates a configuration of a heat exchanger according to one embodiment
of the present invention and Fig. 1(B) is a plan view thereof.
Fig. 2(A) illustrates a configuration of a heat exchanger according to another embodiment
of the present invention and Fig. 2(B) is a plan view thereof.
Fig. 3(A) illustrates a configuration of a heat exchanger according to still another
embodiment of the present invention and Fig. 3(B) is a plan view thereof.
Fig. 4(A) is an enlarged view of a substantial portion of the heat exchanger according
to the embodiment of the present invention in assembling and Fig. 4(B) is an enlarged
view of a substantial portion of the heat exchanger when the assembling processing
is completed.
BEST MODE FOR CARRYING OUT THE INVENTION
[0010] One embodiment of the present invention is described below with reference to the
accompanying drawings. The terms "up," "down," "left" and "right" as used herein only
refers to relative positional relationships but do not specify absolute positions.
[0011] As illustrated in Fig. 1, a heat exchanger of this embodiment includes an inner tube
5 and an outer tube 6 which have a substantially circular lateral cross section ,
wherein upper ends and lower ends of the inner tube 5 and the outer tube 6 are closed
by an upper closing part 9 and a lower closing part 8, respectively. In this example,
the inner tube 5 and the lower closing part 8 are integrally formed. According to
another embodiment, not the lower closing part 8 but the upper closing part 9 may
be integrally formed with the inner tube 5. Alternatively, none of the lower closing
part 8 or the upper closing part 9 is integrally formed with the inner tube 5 but
may be formed detachably.
[0012] A coiled heat-transfer tube 1 is placed in the space 7 defined between the inner
tube 5 and the outer tube 6 such that the coiled heat-transfer tube 1 closely contacts
with or pressure contacts against at least either one of an outer perimeter of the
inner tube 5 or an inner perimeter of the outer tube 6. The coiled heat-transfer tube
1 pierces through the upper closing part 9 and the lower closing part 8, thereby being
contactable with pipes outside the heat exchanger. However, the heat-transfer tube
1 is not fixed to either one of the outer peripheral surface of the inner tube 5 or
the inner peripheral surface of the outer tube 6. A coiled space 4 is defined between
turns of the coiled heat-transfer tube 1. The coiled space 4 having predetermined
intervals is enclosed by the vertically adjacent different turns of the heat-transfer
tube 1 and the inner and outer tubes 5, 6. The illustrated coiled heat-transfer tube
1, inner tube 5 and outer tube 6 are implemented in a cylindrical shape having a vertically
uniform diameter. However, they may be formed into a shape having a vertically varying
diameter (i.e., a circular truncated cone shape or an inverted circular truncated
cone shape).
[0013] A fluid 2 to be processed, e.g., water, an organic solvent, a solution obtained by
dissolving a solute, or a microparticle dispersion liquid, passes through an inside
of the heat-transfer tube 1. A preferable material for the heat-transfer tube 1 can
expand and contract and has a high corrosion and pressure resistance, and robustness
against the target fluid to be processed through the heat-transfer tube. Examples
of the material for the heat-transfer tube include a metal such as stainless steel,
hastelloy, inconel, titanium, copper, and nickel; an acrylic resin such as ABS, polyethylene,
polypropylene, and PMMA; a fluorine based resin such as polycarbonate, PTFE, and PFA;
and an epoxy resin.
[0014] The external section of the heat-transfer tube 1 as the coiled space 4 (in other
words, the coiled space 4 defined between the heat-transfer tube 1 and the heat-transfer
tube 1) is a space for passing a heating medium 3. The heating medium 3 enters and
exists through nozzles 10 formed in the upper closing part 9 and the lower closing
part 8, respectively. Accordingly, the heating medium 3 can be passed through the
space 7 and the coiled space 4. To efficiently and effectively exchange heat of the
fluid 2 to be processed, the fluid 2 to be processed is passed upwardly (i.e., in
a U direction) in Fig. 1 and the heating medium 3 is passed downwardly (i.e., in an
S direction) to create an absolute counterflow. Accordingly, both of the fluid 2 to
be processed and the heating medium 3 are prevented from an increase of a pressure
loss, resulting in securing a large overall heat-transfer coefficient. However, a
flow of both fluids in the same direction should not be excluded from consideration.
[0015] Assembly and disassembly of the heat exchanger according to the present invention
are described below. Initially, the heat-transfer tube 1 is assembled with the lower
closing part 8 and the inner tube 5 which are integrally formed. The above attachment
can be performed smoothly by defining a suitable clearance 4c between the inner tube
5 and the heat-transfer tube 1 (See Fig. 4(A)). After the attachment, the heat-transfer
tube 1 is fixed to the lower closing part 8. The fixation is performed with what having
a tensioning mechanism 11. The tensioning mechanism 11 keeps the expansion or contraction
force for expanding or contracting the diameter of the coiled heat-transfer tube 1
than the diameter the coiled heat-transfer tube 1 naturally has. In the illustrated
example, an interlocking joint 11 is employed as the tensioning mechanism 11. In another
embodiment, the tensioning mechanism may include a clamp, a saddle band, a strap,
and a bracket. In addition, the tensioning mechanism may be a fixation by, for example,
welding or bonding (not illustrated). The tensioning mechanism 11 may be configured
only to keep the expansion or contraction force, whereas, generation of the expansion
or contraction force may be performed by another mechanism. However, in a case of
the interlocking joint 11, it generates as well as keeps the expansion or contraction
force.
[0016] Then, the heat-transfer tube 1 is pulled in the U direction to reduce the diameter
of the coiled heat-transfer tube 1, thereby bringing the heat-transfer tube 1 into
close contact with or pressure contact against the inner tube 5 (Fig. 4(B)). Thereafter,
the outer tube 6 slightly spaced by a gap 4d from the outer diameter of the assembled
coiled heat-transfer tube 1, and the upper closing part 9 are assembled therewith.
The outer tube 6 and the upper closing part 9 may be integrally formed or may be formed
so as to be disassembled.
[0017] More specifically, the slight gap 4d is kept while the heat-transfer tube 1 is pulled
in the U direction. The outer tube 6 is then mounted to the outside of the heat-transfer
tube 1 and the upper closing part 9 is temporally attached thereto. During the temporal
attachment, while the heat-transfer tube 1 is still pulled in the U direction, an
upper end of the heat-transfer tube 1 is fixed to the upper closing part 9, thereby
completing the attachment between the outer tube 6 and the upper closing part 9. The
tensioning mechanism 11 of the upper closing part 9 may be configured to be adjustable
of an upper end position of the outer tube 6 in the same manner as the interlocking
joint 11 of the lower closing part 8 or may be an unadjustable fixing mechanism.
[0018] At the time, for enabling an easy assembling and disassembling, when the coiled heat-transfer
tube 1 that can be expanded or contracted is varied by 10% of the expansion or contraction
amount with respect to a length the coiled heat-transfer tube 1 naturally has, the
load is preferably equal to or less than 10 kg. Also, for the purpose of the low flow
processing, for example, in various chemical experiments, the outer diameter of the
heat-transfer tube 1 is preferably equal to or less than 28 mm. Thereby, the coiled
heat-transfer tube 1 having a smaller coil diameter can be produced and thus the heat
exchanger of a smaller size can be provided.
[0019] The above example is suitable for the heat-transfer tube 1 naturally having an inner
diameter larger than the outer diameter of the inner tube 5. However, in a case where
the inner diameter the heat-transfer tube 1 naturally has is larger than the outer
diameter of the inner tube 5 and the outer diameter the heat-transfer tube 1 naturally
has is larger than the inner diameter of the outer tube 6, the following method is
employable. During the above described temporal attachment, the tensile force in the
U direction is released. Accordingly, the coiled heat-transfer tube 1 attempts to
resume its natural size. As a result, the coiled heat-transfer tube 1 is brought into
close contact with or pressure contact against the inner peripheral surface of the
mounted outer tube 6. In that state where the heat-transfer tube close contacts with
or pressure contacts against the outer tube 6, the upper end of the heat-transfer
tube 1 is fixed to the upper closing part 9 to complete the attachment between the
outer tube 6 and the upper closing part 9.
[0020] Alternatively, in a case where the inner diameter of the heat-transfer tube 1 it
naturally has is larger than the outer diameter of the inner tube 5 and the outer
diameter of the heat-transfer tube 1 it naturally has is smaller than the inner diameter
of the outer tube 6, the following method is also employable. In other words, the
heat-transfer tube 1 is attached with a suitable clearance 4c between the inner tube
5 and the heat-transfer tube 1, and the outer tube 6 having a slight gap with the
outer coil diameter of the heat-transfer tube 1 is assembled with the upper closing
part 9. In this state, the heat-transfer tube 1 is pulled in the vertical direction
so that the upper end and the lower end thereof separate from each other by, for example,
operating the interlocking joint 11 to generate the expansion or contraction force
(i.e., a contraction force in this case). Thereby, the diameter of the coiled heat-transfer
tube 1 is reduced to bring the heat-transfer tube 1 into close contact with or pressure
contact against the inner tube 5. The expansion or contraction force is then kept
to secure the close contact or pressure contact state.
[0021] In the above embodiment, the heat-transfer tube 1 is brought into close contact with
or pressure contact against the inner tube 5. However, in another embodiment, the
heat-transfer tube 1 is pushed downwardly into the outer tube 6 from above, i.e.,
in the S direction (in other words, the upper end is brought closer to the lower end)
to increase the coiled diameter, thereby bringing the heat-transfer tube 1 into close
contact with or pressure contact against the outer tube 6. Further, in the above example,
the upper end and the lower end of the heat-transfer tube 1 is pushed or pulled in
the coil axial direction. However, the upper end and the lower end of the heat-transfer
tube 1 may be pushed or pulled in a direction in which a helical structure of the
coil extends. The pushing or pulling direction can be changed, as required, provided
that the expansion or contraction force can be generated. In the above description,
the vertical orientation is exemplified, but the orientation may be inverted. More
specifically, up and down can be interpreted as one side and the other side, respectively.
[0022] According to the above invention, the heat-transfer tube 1 can be placed in the space
7 defined between the inner tube 5 and the outer tube 6 so as to be on a concentric
circle of the inner and the outer tubes. Therefore, the coiled space 4 sandwiched
between the adjacent coiled sections of the heat-transfer tube 1 in the space 7 can
be used as a flow path of the heating medium 3. The heat exchanger according to the
present invention can be disassembled with ease according to a reversed procedure
of the above assembling method.
[0023] In the case where the coiled heat-transfer tube 1 is not fixed in the space 7, the
heat-transfer tube 1 may expand or contract due to the flow resistance of the heating
medium 3, which may invite a case that the pitches between the coiled sections of
the heat-transfer tube 1 become tight. In other words, the flow resistance of the
heating medium 3 causes the coiled sections of the heat-transfer tube 1 become closer
to each other and finally the coiled heat-transfer tube 1 may move to a direction
the coiled space 4 is eliminated. In this case, since the heating medium 3 becomes
not to pass smoothly in the coiled space 4, there arises a problem that the heat exchange
cannot work at all, that the effective/efficient heat exchange cannot be performed,
or that breakage or short-life of the heat-transfer tube 1 may be induced. In the
present invention, although the heat-transfer tube 1 is not fixed, the heat-transfer
tube 1 close contacts with or pressure contacts against at least either one of the
outer perimeter of the inner tube 5 or the inner perimeter of the outer tube 6. Therefore,
the coiled heat-transfer tube 1 can be prevented from the displacement caused due
to the flow resistance that is generated by the flow of the heating medium 3. As a
result, the above described problems can be solved.
[0024] The heat-transfer tube 1 may include a plurality of heat-transfer tubes. The number
of the heat-transfer tubes 1 to be assembled together is not particularly limited.
The number is determined according to a necessary flow rate of the fluid to be processed
or the number of types of fluids to be treated. Examples of assembling the plurality
of heat-transfer tubes are illustrated with reference to Figs. 2(A) and 2(B), and
Figs. 3(A) and 3(B). For example, as illustrated in Fig. 2, in a case of assembling
the heat-transfer tubes 1 having the same coiled diameter, the heat-transfer tube
1a and the heat-transfer tube 1b are assembled with the lower closing part 8 (or the
upper closing part 9) and the inner tube 5, which are integrally formed, and are fixed
at different positions on the lower closing part 8. Then, the heat-transfer tube 1a
and the heat-transfer tube 1b are brought into close contact with or pressure contact
against the inner tube 5 by the above described mechanism, followed by being further
assembled with the outer tube 6 and the upper closing part 9 (or the lower closing
part 8). Accordingly, the plurality of heat-transfer tubes 1 can be assembled. In
another embodiment, as illustrated in Fig. 3, the coiled heat-transfer tubes 1 may
be implemented in a manner that the diameters of the coiled heat-transfer tubes are
located on concentric circles. In this case, the heat-transfer tube 1a is assembled
with the lower closing part 8 (or the upper closing part 9) and the inner tube 5 which
are integrally formed. The heat-transfer tube 1a is then brought into close contact
with or pressure contact against the inner tube 5 by the above described mechanism.
Then, the outer tube 6a spaced from the outer diameter of the coiled heat-transfer
tube 1a by the slight gap is assembled therewith. Subsequently, the heat-transfer
tube 1b is assembled with the lower closing part 8 (or the upper closing part 9) to
bring the heat-transfer tube 1b into close contact with or pressure contact against
the outer peripheral surface of the outer tube 6a by the above described mechanism.
Then, the outer tube 6b and the upper closing part 9 (or the lower closing part 8)
are assembled therewith. Accordingly, the plurality of heat-transfer tubes 1 can be
assembled. In the embodiment illustrated in Fig. 3, the coiled spaces 4a and 4b are
defined. Even in a case where more than three heat-transfer tubes are assembled together,
this configuration can be implemented using a material and an assembling method similar
to those described above. In this case, the assembly can be performed by a combination
of the assembly based on the same diameter and the assembly based on the concentric
circles.
[0025] As described above, passed through the heat-transfer tube 1 is the fluid 2 to be
processed such as water, organic solvent, solution that is produced by dissolving
solute, and microparticle dispersion liquid to be used in the low flow processing,
more specifically, used in various chemical experiments. Therefore, the heat-transfer
tube 1 often needs to be replaced depending on experiment descriptions. Furthermore,
in a case where solid and powder contained in the fluid 2 to be processed, or solute
dissolved in the fluid 2 to be processed is precipitated due to a change of temperature
or concentration or due to drying, such solid matters may adhere or clog inside the
heat-transfer tube 1 to invite a necessity of replacement of the heat-transfer tube
1.
[0026] In a submerged heat exchanger or double-pipe heat exchanger which is used in the
typical low flow processing, especially, in various chemical experiments, a good efficiency
in heat exchange cannot be expected. Therefore, the structure of the heat exchanger
according to the present invention solves the above problems of the submerged heat
exchanger and the double-pipe heat exchanger. Further, as described above, in a case
when the heat-transfer tube 1 is required to be replaced, the heat exchanger according
to the present invention is characterized in that it can be assembled or disassembled
very easily because the heat exchanger according to the present invention has a very
simple structure in comparison with the multipipe heat exchanger and the plate type
heat exchanger. Also, in addition to the easy replacement of the heat-transfer tube,
the heat exchanger can be easily disassembled and cleaned, so that it is not necessary
to dispose the heat exchanger itself or perform a costly cleaning of the heat exchanger
as it is done in the conventional heat exchanger.
[0027] There are a plurality of modes for achieving the close contact with or the pressure
contact against the inner tube 5 and the outer tube 6 by using the elastic deformation
of the heat-transfer tube. Such modes are described below.
(First Mode) It is provided that the outer diameter of the inner tube 5 is α, the
inner diameter of the outer tube 6 is β, the inner diameter of the coiled heat-transfer
tube 1 is γ, and the outer diameter of the coiled heat-transfer tube 1 is θ. If the
inner diameter γ of the coiled heat-transfer tube 1 is larger than or equal to the
outer diameter α of the inner tube 5 (α ≤ γ), when the inner tube 5 is inserted into
the heat-transfer tube 1 leaving it in the natural state and, the heat-transfer tube
1 is pulled in a direction in which both ends separates from each other after the
insertion, the outer diameter α of the inner tube 5 comes to be equal to the inner
diameter γ of the heat-transfer tube 1 by the external force to bring the heat-transfer
tube 1 into close contact with or pressure contact against the inner tube 5. Here,
even in a case of α ≤ γ, the inner diameter γ may be increased by compressing the
heat-transfer tube 1 in order to facilitate the insertion.
(Second Mode) If the inner diameter γ of the coiled heat-transfer tube 1 is smaller
than the outer diameter α of the inner tube 5 (α > γ), the inner tube 5 is inserted
while the heat-transfer tube 1 is compressed to expand the inner diameter γ. After
the insertion, when the compressing force is released and the heat-transfer tube 1
is then pulled, as required, the outer diameter α of the inner tube 5 becomes equal
to the inner diameter γ of the heat-transfer tube 1 due to the elastic deformation
of the heat-transfer tube 1, thereby bringing the heat-transfer tube 1 into close
contact with or pressure contact against the inner tube 5.
(Third Mode) If the outer diameter θ of the coiled heat-transfer tube 1 is smaller
than or equal to the inner diameter β of the outer tube 6 (β ≥ θ), the heat-transfer
tube 1 in its natural state is inserted into the outer tube 6 and, the heat-transfer
tube 1 is then compressed after the insertion, the inner diameter β of the outer tube
6 comes to be equal to the outer diameter θ of the heat-transfer tube 1 by the external
force, thereby bringing the heat-transfer tube 1 into close contact with or pressure
contact against the outer tube 6. Even in a case of β ≥ θ, the heat-transfer tube
1 may be pulled to reduce the outer diameter θ thereof in order to facilitate the
insertion.
(Fourth Example) If the outer diameter θ of the coiled heat-transfer tube 1 is larger
than the inner diameter β of the outer tube 6 (β < θ), the heat-transfer tube 1 is
pulled to reduce the diameter thereof, and then inserted into the outer tube 6. After
the insertion, when the pulling force is released and the heat-transfer tube 1 is
then compressed, as required, the inner diameter β of the outer tube 6 comes to be
equal to the outer diameter θ of the heat-transfer tube 1, thereby bringing the heat-transfer
tube 1 into close contact with or pressure contact against the outer tube 6.
[0028]
Table 1
Close-contacting component |
Relation between diameters before insertion |
State of heat-transfer tube 1 during insertion |
External force after insertion |
Inner tube 5 |
α≤γ |
Natural state or compressed state |
Pulling force |
Inner tube 5 |
α>y |
Compressed state |
Unnecessary or Pulling force |
Outer tube 6 |
β≥θ |
Natural state or pulled state |
Compressing force |
Outer tube 6 |
β < θ |
pulled state |
Unnecessary or Compressing force |
DESCRIPTION OF REFERENCE NUMERALS
[0029]
1: Heat-Transfer Tube
3: Heating Medium
4: Coiled Space
5: Inner Tube
6: Outer Tube
8: Lower Closing Part
9: Upper Closing Part
11: Tensioning Mechanism
1. A heat exchanger comprising a coiled heat-transfer tube placed in a space defined
between an inner tube and an outer tube, an inside space of the heat-transfer tube
being used as one of flow paths, a coiled space defined between coiled sections of
the heat-transfer tube in the space being used as the other flow path, and heat being
exchanged between one fluid and the other fluid, the heat exchanger further comprising:
a tensioning mechanism for keeping an expansion or contraction force acting to expand
or contract a diameter of the coiled heat-transfer tube than a diameter the heat-transfer
tube naturally has,
wherein the heat is exchanged between one fluid and the other fluid while the expansion
or contraction force is applied to the heat-transfer tube by the tensioning mechanism.
2. The heat exchanger of Claim 1 characterized in that the heat-transfer tube is not fixed to either one of an outer peripheral surface
of the inner tube or an inner peripheral surface of the outer tube, and
wherein the diameter of the coiled heat-transfer tube is expanded or contracted than
the diameter the heat-transfer tube naturally has, and the heat-transfer tube is brought
into close contact with or pressure contact against the inner tube or the outer tube
by the expansion or the contraction.
3. The heat exchanger of Claim 1 or 2 characterized in that a load applied in a coil axis direction of the heat-transfer tube is equal to or
less than 10 kg when a length of the coiled heat-transfer tube in the coil axis direction
is varied by 10% in comparison with a length the coiled heat-transfer tube naturally
has.
4. The heat exchanger of Claim 3 characterized in that the heat-transfer tube is made of at least a material selected from the group consisting
of metals such as stainless steal, hastelloy, inconel, titanium, copper, and nickel;
acrylic resins such as ABS, polyethylene, polypropylene, PMMA; fluorine based resins
such as polycarbonate, PTFE, and PFA; and an epoxy resin.
5. The heat exchanger of Claim 4 characterized in that the outer diameter of the heat-transfer tube 1 is equal to or less than 28 mm.
6. A heat exchanger comprising a coiled heat-transfer tube placed in a space defined
between an inner tube and an outer tube, an inside space of the heat-transfer tube
being used as one of flow paths, and a coiled space defined between coiled sections
of the heat-transfer tube in the space being used as the other flow path, heat being
exchanged between one fluid and the other fluid,
wherein the coiled heat-transfer tube is elastically deformed from its natural state
to be brought into close contact with or pressure contact against the inner tube or
the outer tube, and the heat is exchanged between one fluid and the other fluid while
the heat-transfer tube is elastically deformed.