U.S. patent application number 14/125546 was filed with the patent office on 2014-08-14 for enhanced condensation heat-transfer tube.
The applicant listed for this patent is Golden Dragon Precise Copper Tube Group Inc.. Invention is credited to Qianfang Li, Xinchun Sun, Chenhui Wang, Zhijun Wang, Yongqiang Wu, Xiaoguang Zhang.
Application Number | 20140224464 14/125546 |
Document ID | / |
Family ID | 51296651 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140224464 |
Kind Code |
A1 |
Wu; Yongqiang ; et
al. |
August 14, 2014 |
ENHANCED CONDENSATION HEAT-TRANSFER TUBE
Abstract
This invention provides an enhanced condensation heat-transfer
tube, which is furnished with spiral fins on the outer surface.
Axial spacing between the said fins regularly changes in width. In
a preferred embodiment, the said fins regularly change in height
along the axle. Such spiral fins with even changes in height and
spacing change the surface tension of the condensate membrane
between the fins outside of the tube, so as to enhance the
"Gregorig" effect (average heat resistance reduces due to uneven
thickness of condensate membranes). In this way, it further
strengthens condensation heat transfer effects outside of the tube.
At the same time, it accelerates flowing of the condensate to the
bottom, enhances heat transfer effect, and improves the tube bundle
effect.
Inventors: |
Wu; Yongqiang; (Xinxiang
City, CN) ; Wang; Zhijun; (Xinxiang City, CN)
; Sun; Xinchun; (Xinxiang City, CN) ; Wang;
Chenhui; (Xinxiang City, CN) ; Zhang; Xiaoguang;
(Xinxiang City, CN) ; Li; Qianfang; (Xinxiang
City, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Golden Dragon Precise Copper Tube Group Inc. |
Xinxiang City, Henan |
|
CN |
|
|
Family ID: |
51296651 |
Appl. No.: |
14/125546 |
Filed: |
January 8, 2013 |
PCT Filed: |
January 8, 2013 |
PCT NO: |
PCT/CN2013/070226 |
371 Date: |
December 11, 2013 |
Current U.S.
Class: |
165/184 |
Current CPC
Class: |
F28F 2215/04 20130101;
F28F 1/36 20130101; F28D 2021/0063 20130101; F28F 1/422 20130101;
F28F 13/187 20130101 |
Class at
Publication: |
165/184 |
International
Class: |
F28F 1/36 20060101
F28F001/36 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2012 |
CN |
20120181289.2 |
Claims
1. An heat-transfer tube for enhanced condensation, comprising a
tube Body, and outer spiral fins integrated on outer surface of the
tube body wherein the spiral fins are featured by regular changes
in axial direction and in the width of spacing between the said
fins.
2. The heat-transfer tube according to claim 1, wherein said spiral
fins having smooth surface; or said spiral fins being slotted fins
by grooving the smooth fin on the top or on both rides.
3. The heat-transfer tube according to Claim 1, wherein 26 to 60 of
said spiral tins are provided in every inch along the axial
direction of the outer surface of the tube body and the spiral fins
are axially spaced 0.4 to 1 mm.
4. The heat-transfer tube according to claim 1, wherein the spacing
between fins regularly changes in the axial direction with
alternating wide and narrow spacing; or the spacing between fins
regularly changes in the axial direction with alternating wide
spacing and two narrow spacings; or the spacing between fins
regularly changes in the axiai direction with alternating two wide
spacings and one narrow spacing.
5. The heat-transfer tube ncording to claim 1, wherein said spiral
fins have regular changes in the height of the said spiral fins in
the axial direction.
6. The heat-transfer tube according to claim 5, wherein said spiral
fins are 0.1 to 0.4 mm thick, with their height ranging between 0.4
to 1.5 mm.
7. The heat-transfer tube according to claim 5, is featured by the
following: the height of the said spiral fins regularly changes
along the axial direction with alternating one high fin and one
short fin; or the height of the said spiral fins regularly changes
along the axial direction with alternating one high fin and two
short fins; or the height of the said spiral fins regularly changes
along the axial direction with alternating two high fins and one
short fin.
8. The heat-transfer tube according to claim 1, is featured by that
the helical angle of the said spiral fins ranges from 0.3.degree.
to 1.5.degree..
9. The heat-transfer tube according to claim 1, wherein threaded
ridges are furnished on the inner surface of the said heat-transfer
tube.
10. The heat-transfer tube according to claim 9, wherein the said
threaded ridges are angled between the threaded ridge and the axle
ranging from 30.degree. to 60.degree.; said threaded ridge has 6 to
60 internal threads, with their height ranging from 0.1 o 0.6
mm.
11. The heat-transter tube according to claim 5, wherein threaded
ridges are furnished on the inner surface of the said heat-transfer
tube.
12. The heat-transfer tube according to claim 11, wherein the said
threaded ridges are angled between the threaded ridge and the axle
ranging from 30.degree. to 60.degree.; said threaded ridge has 6 to
60 internal threads, with their height ranging from 0.1 to 0.6 mm.
Description
BACKGROUND
[0001] 1. The Field of the Present Disclosure
[0002] This invention involves the technical field of heat-transfer
tubes, especially a type of enhanced condensation heat-transfer
tube.
[0003] 2. Description of Related Art
[0004] With the concept of energy conservation and high efficiency
being widely promoted, requirements for heat transfer performance
in condenser design has gradually increased and a highly-efficient
heat-transfer tube is the key factor affecting the heat transfer
performance of a condenser. A Chinese patent document, with
publication number of CN1982829A, discloses a type of copper
heat-transfer tube with triangular smooth fins on the outside. Such
smooth fins increase the heat transfer area. When used in a
condenser, it reduces condensate membrane and accelerates
condensate dripping. Thus, it is of higher heat transfer efficiency
than a smooth tube. However, a smooth fin easily enables "bypass"
of condensate and renders the condensate to flow less smoothly. As
a result, condensation thermal resistance of the fins increases and
the heat transfer efficiency is reduced. Another Chinese patent
document, with the publication number CN101813433A, discloses
another type of heat-transfer tube, for which a top slotted fin
structure is adopted. Its serration structure may pierce through
the condensate membrane and the fin platform can enhance
condensation heat transfer performance to a certain extent.
[0005] Structures of the said heat-transfer tube of condensers in
current use are shown in FIG. 1 and FIG. 2 (FIG. 3 shows the
front-view projection). Fins are distributed on the surface of the
heat-transfer tube body, which improves the heat transfer
performance on the condensation side to a certain extent. However,
as the fins are of the same height and spacing and are evenly
distributed, surface tension of the condensate cannot be put into
full use to improve heat transfer performance. As a result, the
heat transfer efficiency of the heat-transfer tube is relatively
low, failing to fully meet the optimal requirements of
refrigerating equipment for heat transfer performance of
condensers.
[0006] The features and advantages of the present disclosure will
be set forth in the description which follows, and in pal will be
apparent from the description, or may be learned by the practice of
the present disclosure without undue experimentation. The features
and advantages of the present disclosure my be realized and
obtained by means of the instruments and combinations particularly
pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The features and advantages of the disclosure will become
apparent from a consideration of the subsequent detailed
description presented in connection with the accompanying drawings
in which:
[0008] FIG. 1 is the structural diagram 1 of an enhanced
condensation heat-transfer tube in current use;
[0009] FIG. 2 is the structural diagram 2 of an enhanced
condensation heat-transfer tube in current use;
[0010] FIG. 3 shows the front view of an enhanced condensation
heat-transfer tube in current use;
[0011] FIG. 4 shows a front view of the first embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0012] FIG. 5 shows a front view of the second embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0013] FIG. 6 shows a front view of the third embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0014] FIG. 7 shows a front view of the fourth embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0015] FIG. 8 shows a front view of the fifth embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0016] FIG. 9 shows a front view of the sixth embodiment of the
enhanced condensation heat-transfer tube as described in this
invention;
[0017] FIG. 10 shows a front view of the seventh embodiment of the
enhanced condensation heat-transfer tube as described in this
invention
DETAILED DESCRIPTION
[0018] This invention solves the technical problem of low efficient
heat transfer performance by providing an enhanced condensation
heat-transfer tube with improved heat transfer performance.
[0019] To solve the above problems, the present invention discloses
a type of enhanced condensation heat-transfer tube, which is
furnished with spiral fins on the outer surface and features
regular changes in axial direction and in the width of spacing
between the said fins.
[0020] In preferred embodiments, for the said spiral fins, smooth
fins are used; or slotted fins, formed by grooving on the top or
both sides of smooth fins, are used.
[0021] In preferred embodiments, 26 to 60 of said spiral fins are
arranged every inch along the axle and the axial spacing between
the fins ranges from 0.4 to 1 mm.
[0022] In preferred embodiments, spacing between the said fins
changes along the axle with alternating wide spacing and narrow
spacing; or spacing between the said fins changes along the axle
with alternating one wide spacing and two narrow spacing; or
spacing between the said fins changes along the axle with
alternating two wide spacing and one narrow spacing.
[0023] In preferred embodiments, the height of the said spiral fins
regularly changes in the axial direction.
[0024] in preferred embodiments, the said spiral fins are 0.1 to
0.4 mm thick with their heights ranging from 0.4 to 1.5 mm.
[0025] In preferred embodiments, the height of the said spiral fins
regularly changes along the axle with alternating one high fin and
one short fin; or the height of the said spiral fins regularly
changes along the axle with alternating one high fin and two short
fins; or the height of the said spiral fins regularly changes along
the axle with alternating two high fins and one short fin.
[0026] In preferred embodiments, the helical angle of the said
spiral fins ranges from 0.3.degree. to 1.5.degree..
[0027] In preferred embodiments, a threaded ridge is provided on
the inner surface of the said heat-transfer tube.
[0028] In preferred embodiments, the angle between the said
threaded ridge and the axle ranges from 30.degree. to 60.degree.;
there are 6 to 60 internal threads on the threaded ridge, with
heights ranging from 0.1 to 0.6 mm.
[0029] Compared to existing technologies, this invention is
advantageous in the following aspects:
[0030] The preferred embodiments of this invention disclose that
the spacing between the fins on the outside surface of the enhanced
condensation heat-transfer tube and the height of the fins vary.
Surface tension of the condensate changing evenly can be put into
full utilization to reduce the thickness of the condensate
membrane. Uneven distribution of thickness in condensate membranes
may reduce average heat resistance and enhance the "Gregorig"
effect, so as to increase the coefficient of heat transfer on the
outer surface of the heat-transfer tube. At the same time, even
changes in surface tension and variation of the curvature reduce
the retention of the condensate and accelerate its dripping so as
to improve heat transfer performance and mitigate the "tube bundle
effect". Heat transfer efficiency inside and outside of the tube
provides optimal combination to increase the overall heat transfer
efficiency of the enhanced condensation heat-transfer tube.
[0031] Reference FIG. 4 shows a front-view projection of the first
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, there
are spiral fins on the outer surface of the heat-transfer tube and
spacing between the fins varies regularly along the axle with
alternating wide and narrow spacing. in this embodiment, 26-60
spiral fins are arranged per inch along the axle, with axial
spacing of 0.4-1 mm. The fins are 0.1 to 0.4 mm thick, with a
helical angle of 0.3.degree. to 1.5.degree. and a height of 0.4 to
1.5 mm. In addition, the spiral fins can be smooth fins or slotted
fins formed by grooving on the top or on both sides of the smooth
fins. As spacing between the fins varies regularly, fins of such
structure enable an even change in the surface tension of the
condensate between fins as well as an even change in the thickness
of condensate membrane correspondingly. It may reduce average heat
resistance and enhance the "Gregorig" effect to improve the
coefficient of heat transfer on the outer surface of the
heat-transfer tube. At the same time, even changes in surface
tension and surface curvature reduce retention of condensate
between fins and enables the condensate to flow and drip quickly to
the bottom of the fins, so as to improve condensation heat transfer
performance and mitigate the "tube bundle effect". Fins of such
structure can be formed by intrusion using a combination of tools,
without increasing metal consumption.
[0032] Reference FIG. 5 shows a front-view projection of the second
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, the
spacing between fins varies regularly with alternating one wide
spacing and two narrow spacings. The rest are the same as those in
the first embodiment.
[0033] Reference FIG. 6 shows a front-view projection of the third
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, the
spacing between fins varies regularly with alternating two wide
spacing and one narrow spacings. The rest are the same as those in
the first embodiment.
[0034] Reference FIG. 7 shows a front-view projection of the fourth
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, there
are fins on the outer surface of the heat-transfer tube with their
height varying regularly along the axle with alternating one high
fin and one short fin. In this embodiment, shod fins are 0.4 to 1.0
mm high, white high fins are 0.6 to it 1.5 mm high. Fins of such
structure enable even change in the surface tension of the
condensate between fins. Correspondingly, thickness of the
condensate membrane varies evenly in order to reduce average heat
resistance and enhance the "Gregorig" effect to improve the
coefficient of heat transfer on the outer surface of the
heat-transfer tube. At the same time, even changes in surface
tension and surface curvature reduce retention of condensate
between fins and enable the condensate to flow and drip quickly to
the bottom of the fins, so as to improve condensation heat transfer
performance and mitigate the "tube bundle effect". Fins of such
structure can be formed by intrusion using a combination of tools,
without increasing metal consumption.
[0035] Reference FIG. 8 shows a front-view projection of the fifth
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, fins are
arranged at such height varying regularly with alternating one high
fin and two short fins. The rest are the same as those in the
fourth embodiment.
[0036] Reference FIG. 9 shows a front-view projection of the sixth
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, fins are
arranged at such height varying regularly with alternating two high
fins and one short fin. The rest are the same as those in the
fourth embodiment.
[0037] The above embodiments of this invention can be combined to
have different shapes of fins with their spacing and height
varying.
[0038] In addition, in the above preferred embodiments of this
invention, dedicated equipment can be used to acquire a threaded
ridge 1 in the tube so as to improve the coefficient of heat
transfer in the tube. The angle between the threaded ridge 1 and
the axle is from 30.degree. to 60.degree.; there are 6 to 60
internal threads, and the ridges are 0.1 to 0.6 mm high. Threaded
ridge 1 may damage the boundary of the fluid in the tube and
increase disturbance to fluid in the tube, so as to enhance heat
transfer and improve the coefficient of heat transfer in the
tube.
[0039] Reference FIG. 10 shows a structural diagram of the seventh
embodiment of the enhanced condensation heat-transfer tube
described in this invention. In this preferred embodiment, the
height of the fins varies regularly in the axial direction with
alternating one high tin and one low fin. At the same time, spacing
between fins varies regularly along the axle with alternating one
wide spacing and one narrow spacing.
[0040] The specific structure of the enhanced heat-transfer tube
for condenser as described in this invention will be introduced in
the following in combination with specific embodiments:
[0041] When the enhanced condensation heat-transfer tube described
in this invention is processed and manufactured as per the
structure shown in FIG. 10, copper, copper alloy, or other metal
materials can be used for the tube body. The tube will have an
outer diameter of 19 mm and wail thickness of 1.13 mm. Specialized
tube milling and metal spinning methods will be adopted for
simultaneous and integrated processing of the outer and inner of
the tubesurface. Spiral fins will be processed along the
circumference direction on the outer surface of the tube body. Fins
will be spaced at d1 of 0.53 mm or d2 of 0.61 mm and have a height
h1 of 0.75 mm or h2 of 0.9 mm. The top of the fins will be grooved
with slots by roll pressing and 120 slots will be provided along
the circumference direction.
[0042] In addition, dedicated equipment will be used to process a
threaded ridge 1 on the inner surface of the tube to improve the
coefficient of heat transfer outside and inside the tube. In the
seventh embodiment of this invention, the threaded ridge 1 is 0.38
mm high, the angle between the ridge and the axle is 42.degree.,
and there are 45 threads.
[0043] According to statistics obtained from actually measured
data, when refrigerant R134a is used, the condensation heat
transfer performance of this invention is 12% higher compared with
existing technologies.
[0044] In the above embodiments of this invention, considering the
heat transfer performance and cost performance of metal materials,
copper is preferred to make this condensation heat-transfer tube.
Other metal materials such as copper alloy, aluminum, aluminum
alloy, low carbon steel, and copper and aluminum composite can also
be used.
[0045] All embodiments in this Specification are described in a
progressive manner. Description of each embodiment is emphasized on
its difference from other embodiments and reference can be made to
each other for the identical and similar parts of the
embodiments.
[0046] This summary introduces in detail a type of enhanced
condensation heat-transfer tube provided in this invention. It
elaborates the principles and implementation methods of this
invention through specific examples. Description of the above
embodiments is merely used to help understand the core idea of this
invention. At the same time, common technicians in this field may
change the specific embodiment methods and application scope in
line with the idea of this invention. To sum up, the contents of
this Specification shall not be construed as the limit to this
invention.
* * * * *