U.S. patent application number 14/356533 was filed with the patent office on 2015-10-22 for a straight fin tube with bended fins condensing heat exchanger.
This patent application is currently assigned to Suzhou CQ Heat Exchanger Co., Ltd.. The applicant listed for this patent is SUZHOU CQ HEAT EXCHANGER CO. LTD. Invention is credited to Shuqing CUI.
Application Number | 20150300687 14/356533 |
Document ID | / |
Family ID | 47573599 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150300687 |
Kind Code |
A1 |
CUI; Shuqing |
October 22, 2015 |
A Straight Fin Tube with Bended Fins Condensing Heat Exchanger
Abstract
A forced convection fin tube condensing heat exchanger for
supplying heat includes a shell, burner and fin tubes bundle. The
burner is at the top of the shell, circular fin tubes bundle
installed around the burner tightly, circularly and coaxially. The
flue channel which is formed by the shell and a row of fin tubes
bundle is below the burner. The flue flows along the flue channel
to flue outlet. There are front and rear water manifolds at the two
ends of the fin tubes. Water baffles inside the rear water manifold
divide the rear water manifold into water inlet and outlet areas.
The water enters the small portion of circular fin tubes bundle
from water inlet area, through the front water manifold, back to
the water outlet area via the main portion of the circular fin
tubes bundle. The use of bended fin tube to improves
efficiency.
Inventors: |
CUI; Shuqing; (Fitchburg,
WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUZHOU CQ HEAT EXCHANGER CO. LTD |
Suzhou, Jiangsu |
|
CN |
|
|
Assignee: |
Suzhou CQ Heat Exchanger Co.,
Ltd.
SIP, Jiangsu Province
CN
|
Family ID: |
47573599 |
Appl. No.: |
14/356533 |
Filed: |
September 21, 2013 |
PCT Filed: |
September 21, 2013 |
PCT NO: |
PCT/CN2013/083871 |
371 Date: |
May 6, 2014 |
Current U.S.
Class: |
126/110R ;
165/104.22 |
Current CPC
Class: |
F24H 1/403 20130101;
F24H 1/445 20130101; F24H 8/006 20130101; Y02B 30/00 20130101; Y02B
30/106 20130101; F24H 1/406 20130101; F24H 3/087 20130101; F24H
9/0084 20130101 |
International
Class: |
F24H 8/00 20060101
F24H008/00; F24H 3/08 20060101 F24H003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 21, 2012 |
CN |
201210353552.1 |
Claims
1. A forced convection fin tube condensing heat exchanger for
supplying heat, comprising: a shell; a burner disposed at an upper
portion of the shell, the burner being fluidly connected to an
air/gas inlet; a plurality of fin tubes disposed in the shell, the
fin tubes being arranged tightly and coaxially about the burner; a
water inlet disposed outside the shell; a water outlet disposed
outside the shell; a flue outlet disposed outside the shell; a flue
channel defined by the shell and a row of fin tubes below the
burner, wherein combustion flue gasses flow from the flue channel
to a flue outlet; a front water manifold disposed at a first end of
the fin tubes; a rear water manifold at a second end of the fin
tubes; and a plurality of water baffles disposed inside the rear
water manifold, the water baffle being configured to divide the
manifold into a water inlet area and a water outlet area, wherein a
flow of water enters a portion of fin tubes through water inlet
area, then arrives at the front water manifold, and then returns to
the water outlet area on the rear water manifold through the other
portion of fin tubes.
2. The forced convection fin tube condensing heat exchanger
according to claim 1, wherein the water baffles inside the rear
water manifold divide the rear water manifold into water inlet area
and outlet area, wherein the flow of water enters the small portion
of circular fin tubes coaxed with burner and a row of fin tubes
above the flue channel through water inlet area, then arrives at
the front water manifold, and then return to the water outlet area
on the rear water manifold through the main portion of circular fin
tubes.
3. The forced convection fin tube condensing heat exchanger
according to claim 1, wherein the water baffles (18) inside the
rear water manifold divide the rear water manifold into water inlet
area and outlet area, the circular finned-tubes have the same
diameter with the row of fin tubes above the flue channel (15), the
quantity of the fin tubes connected to the water inlet area roughly
equals to the quantity of the fin tubes connected to the water
outlet area, if the circular fin tubes have a different diameter
with the row of fin tubes above the flue channel (15), the sum of
the cross section area of the fin tubes connected to the water
inlet area shall roughly equals to the sum of the cross section
area of the fin tubes connected to the water outlet area.
4. The forced convection fin tube condensing heat exchanger
according to claim 1, wherein the fins are bended for some angles
along with the tube axial by bending or squeezing and all the fin
tubes are in contact with adjacent ones of the fin tubes.
5. The forced convection fin tube condensing heat exchanger
according to claim 1, further comprising: a plurality of outer flue
baffles disposed outside the circular fin tubes around the
burner.
6. The forced convection fin tube condensing heat exchanger
according to claim 5, wherein the outer flue baffle include a "V"
type cross section with a radiused portion configured to mate with
ones of the fins of the fin tubes and wherein the interfaces of the
fin tubes disposed in a circle are staggered with the openings
between the flue baffles.
7. The forced convection fin tube condensing heat exchanger
according to claim 1, further comprising: a plurality of lower flue
baffles disposed under the row of fin tubes which are located above
flue channel and below the burner, wherein the lower flue baffles
include a "V" type cross section with a radiused portion configured
to mate with ones of the fins of the fin tubes and wherein the
interface of the fin tubes in the row are staggered with the
openings between the flue baffles.
8. The forced convection fin tube condensing heat exchanger
according to claim 1, further comprising: an air pre-heater
disposed inside the flue channel, wherein the air pre-heater is
located inside and along the flue channel and connected with an air
inlet, the flue exhaust being a 4-way connector, wherein the flue
exhaust is disposed on a top portion of the forced convection fin
tube condensing heat exchanger; and a condensate outlet disposed at
a bottom portion of the forced convection fin tube condensing heat
exchanger and the air inlet being disposed in a middle portion of
the forced convection fin tube condensing heat exchanger.
9. The forced convection fin tube condensing heat exchanger
according to claim 8, wherein the air pre-heater disposed inside
the flue channel includes one or more cuboidal or cylindrical air
inlet tubes.
10. A forced convection fin tube condensing heat exchanger
comprising: a shell; a burner disposed below the shell, the burner
being fluidly connected to an air/gas inlet; a plurality of fin
tubes disposed in the shell, the fin tubes being arranged tightly
and coaxially about the burner; a water inlet disposed outside the
shell; a water outlet disposed outside the shell; a flue outlet
disposed outside the shell; a flue channel defined by the shell and
a row of fin tubes below the burner, wherein combustion flue gasses
flow from the flue channel to a flue outlet; a front water manifold
disposed at a first end of the fin tubes; a rear water manifold at
a second end of the fin tubes; and a plurality of water baffles
disposed inside the rear water manifold, the water baffle being
configured to divide the manifold into a water inlet area and a
water outlet area, wherein a flow of water enters a small portion
of the fin tubes that are coaxial with the burner and a row of
upper fin tubes disposed above the flue channel, the flow of water
passing through the water inlet area, through the front of the
water manifold, and then being conveyed to the water outlet area on
the rear water manifold through a main portion of the fin tubes.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a national stage application and claims
priority to PCT/CN2013/083871, filed on Sep. 21, 2013, which claims
priority to CN 201210353552.1, filed on Sep. 21, 2012, the
disclosures of which are incorporated herein by reference in their
entireties.
FIELD OF THE INVENTION
[0002] This invention relates generally to equipment in the heating
industry field. More particularly, the invention is related to a
forced convection straight fin tube condensing heat exchanger for
supplying heat.
BACKGROUND OF THE INVENTION
[0003] As far back as the Middle East oil crisis in the in 20th
century, to save the energy, the high efficient condensing boiler
was developed in Europe. The outstanding feature of the boiler is
that the efficiency is 10% higher than the conventional boiler.
Abundant water vapor in the flue is condensed and releases the
latent heat of vaporization because the flue temperature can be
decreased to below the dew point. This has the effect of energy
saving. The condensing heat exchanger is developed and designed
based on the principle of the condensing boiler.
[0004] The available heat from the combustion flue gas includes two
parts: one is the sensible heat (e.g., the sensed heat) in the
flue; the other part is the latent heat of water vapor in the flue.
The conventional boiler has very high flue temperature because of
the limitation of the structure. Therefore only sensible heat can
be utilized. However, condensing boiler can not only use sensible
heat in the flue but also the latent heat because of the low flue
temperature. In this way, the efficiency of the condensing boiler
can be greatly increased. In order to absorb the energy in the high
temperature flue and collect the condensing water in the low
temperature flue, a two-stage heat exchanger is employed normally.
The high temperature flue enters the main heat exchanger and then
condensing heat exchanger in sequence; the water flows in an
opposite direction, the water enters the condensing heat exchanger
first, and then enters the main heat exchanger. The water absorbs
the sensible heat from the combustion flue gas after absorbing the
waste heat of the high temperature flue in the condensing heat
exchanger. The flue temperature decreases to a very low temperature
after the sensible and latent heat in the heat exchangers has been
absorbed by the water. In order to vent the flue securely, the
forced convection method is applied. At the same time, the forced
convection makes the boiler water absorbs the sensible and latent
heat as much as possible. Therefore, the condensing heat exchanger
utilizes the energy in the flue which was lost. The effect of the
condensing heat exchanger depends on how much the waste energy is
used.
[0005] The flue gas is normally in an overheated state before
entering the condensing heat exchanger. It becomes saturation
gradually as the flue temperature decreases and water vapor
condenses. According to the test result, the flue at the condensing
heat exchanger outlet is close to saturation status when the flue
temperature is around 50.degree. C. How close to the saturation
status depends on the composition of the flue, the structure of the
heat exchanger and heat transfer process. The testing result shows
there are still some dead zones or short-circuit in the flue path.
It decreases the heat exchanging efficiency.
[0006] The heat exchanger of the conventional (non-condensing)
boiler is made by carbon steel or cast iron. The flue temperature
is higher than 150.degree. C. normally. The heat exchanger is not
designed to absorb the sensible and latent heat when the water
vapor condensing, and there is no condensate.
[0007] The condensing boiler is high efficient boiler with the
features of energy saving and environmental protection. It is the
future of the boiler industry and has been widely used. The life
the condensing boiler will be shortened significantly if the carbon
steel or cast iron is used because the boiler generates a lot of
acid condensing water. So the material of the condensing heat
exchanger should be stainless steel or cast aluminum. At present,
most condensing heat exchangers are made with stainless steel tube
or cast aluminum.
[0008] It is a proven technology to make cast aluminum heat
exchanger, but the capacity is limited. It is very difficult to
make the big cast aluminum parts. Typically, the bigger the cast,
the higher the mold cost, the more complex manufacturing process
and the higher scrap rate.
[0009] The efficiency can be around 96% maximally by using
stainless steel or cast aluminum.
[0010] There will be no condensing water if the return water
temperature is higher than 60.degree. C. At this point, only the
sensible heat in the flue can be saved. The heat efficiency of the
non-condensing boiler is only around 87%.
[0011] The air pre-heater is applied in the large boiler in power
stations normally. There is no such application in the heating
boiler.
[0012] The conventional heat exchangers are designed according to
the requirements from the different customers and the sizes of the
heat exchangers are varied very much according to these
requirements. Because there are a lot of components involved in the
manufacture of heat exchangers, manufacturing many sizes of heat
exchangers is not good practice for mass production.
[0013] While conventional heat exchangers have relatively good
performance, there is still room for significant improvements in
performance. A specific list of technical problems in need of
improvement include: dead zones of flue flow and insufficient heat
exchanging because of the poor heat exchanger structure design;
increase the flue side heat transfer surface and efficiency by
improving the heat transfer structure; to make the size smaller
under the same heat transfer output; to integrate an air pre-heater
into the heat exchanger to get the opportunity of third heat
exchanging; increase the temperature of the inlet air; and decrease
the flue temperature further. Accordingly, there is a need in the
art to improve the heat exchanger.
SUMMARY OF THE INVENTION
[0014] The foregoing needs are met, to a great extent, by the
present invention, wherein aspects of a heat exchanger are
provided.
[0015] An embodiment of the present invention pertains to a forced
convection fin tube condensing heat exchanger for supplying heat.
The forced convection fin tube condensing heat exchanger includes a
shell, a burner, a group of fin tubes in the shell, a water inlet,
a water outlet, a flue outlet on the shell, and a connector between
the burner and air/gas mixture. The burner is under the shell. A
set of fin tubes are installed around the burner tightly and
coaxially. The flue channel is formed by the shell and a row of fin
tubes below the burner. The flue gas flows along the flue channel
to flue outlet. There are front water manifold and back water
manifold at the two ends of the fin tubes. The water baffles inside
the rear water manifold divide the rear water manifold into water
inlet area and outlet area. The water enters the small portion of
circular fin tubes coaxed with burner and a row of fin tubes above
the flue channel through water inlet area, then arrives at the
front water manifold, and then return to the water outlet area on
the rear water manifold through the main portion of circular fin
tubes.
[0016] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
water baffles inside the back water manifold divide the rear water
manifold into water inlet area and outlet area. The water enters
the small portion of circular fin tubes coaxed with burner and a
row of fin tubes above the flue channel through water inlet area,
then arrives at the front water manifold, and then return to the
water outlet area on the back water manifold through the main
portion of circular fin tubes.
[0017] A preferred option of the forced convection finned-tube
condensing heat exchanger for supplying heat is characterized by
water baffles inside the rear water manifold divide the rear water
manifold into water inlet area and outlet area. The circular fin
tubes have the same diameter with the row of fin tubes above the
flue channel. The quantity of the fin tubes connected to the water
inlet area roughly equals to the quantity of the fin tubes
connected to the water outlet area. If the circular fin tubes have
a different diameter with the row of fin tubes above the flue
channel, the sum of the cross section area of the fin tubes
connected to the water inlet area shall roughly equals to the sum
of the cross section area of the fin tubes connected to the water
outlet area.
[0018] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
making the fins bended for some angles along with the tube axial by
bending or squeezing, and to arrange the fin tubes next to each
other closely and tightly.
[0019] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
flue baffles outside the circular fin tubes around the burner.
[0020] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
the cross section of the flue baffle is "V" type with radian,
fitting with the fins of the fin tubes. The interfaces of the fin
tubes in circle are staggered with the openings between the flue
baffles.
[0021] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
the flue baffles being under the row of fin tubes which are located
above flue channel and below the burner. The cross section of the
flue baffles is "V" type with radian, fitting with the fins of fin
tubes. The interface of the fin tubes in the row are staggered with
the openings between the flue baffles.
[0022] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by an
air pre-heater being disposed inside the flue channel. The air
pre-heater is located inside and along the flue channel, and
connected with air inlet. The flue exhaust is a 4-way connector,
the flue exhaust on the top, the condensate outlet at the bottom
and the air inlet in the middle.
[0023] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
the air pre-heater being disposed inside the flue channel is one or
several cuboids or cylinder air inlet tube.
[0024] A preferred option of the forced convection fin tube
condensing heat exchanger for supplying heat is characterized by
the burner being disposed under the shell. A set of fin tubes are
installed around the burner tightly and coaxially. The flue channel
is formed by the shell and a row of fin tubes below the burner. The
flue gas flows along the flue channel to flue outlet. There are
front water manifold and rear water manifold at the two ends of the
fin tubes. The water baffles inside the rear water manifold divide
the rear water manifold into water inlet area and outlet area. The
water enters the small portion of circular fin tubes coaxed with
burner and a row of fin tubes above the flue channel through water
inlet area, then arrives at the front water manifold, and then
return to the water outlet area on the rear water manifold through
the main portion of circular fin tubes.
[0025] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0026] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0027] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a right side view of a forced convection fin tube
condensing heat exchanger for supplying heat according to an
embodiment.
[0029] FIG. 2 is a front view of the forced convection fin tube
condensing heat exchanger for supplying heat according to an
embodiment.
[0030] FIG. 3 is a perspective view of a forced convection fin tube
condensing heat exchanger for supplying heat according to an
embodiment.
[0031] FIG. 4 is a sectional view of the forced convection fin tube
condensing heat exchanger for supplying heat according to an
embodiment.
[0032] FIG. 5 is an operation (flow path) view of the forced
convection fin tube condensing heat exchanger for supplying heat
according to an embodiment.
[0033] FIG. 6 is a right side sectional view of the forced
convection fin tube condensing heat exchanger with an air
pre-heater according to an embodiment.
[0034] FIG. 7 is a detailed view A of the forced convection fin
tube condensing heat exchanger for supplying heat according to an
embodiment.
[0035] FIG. 8 is a detailed view B of the forced convection fin
tube condensing heat exchanger for supplying heat according to an
embodiment.
[0036] FIG. 9 is a sectional view of the forced convection fin tube
condensing heat exchanger with the burner located at the bottom
according to another embodiment.
[0037] FIG. 10 is an operation (flow path) view of the forced
convection fin tube condensing heat exchanger with the burner
located at the bottom according to the embodiment of FIG. 9.
[0038] FIG. 11 is a front body view of the fin tube with bended
fins for the circular fin tubes bundle according to an
embodiment.
[0039] FIG. 12 is a left view of the fin tube with bended fins for
the circular fin tube bundle according to an embodiment.
[0040] FIG. 13 is a front body view of the fin tube with bended
fins for the row of fin tubes bundle according to an
embodiment.
[0041] FIG. 14 is a left view of the fin tube with bended fins for
the row of fin tubes bundle according to an embodiment.
[0042] FIG. 15 is a right view of the forced convection fin tube
condensing heat exchanger for supplying heat with an air pre-heater
having two tubes according to the embodiment of FIG. 9.
[0043] FIG. 16 is a right view of the forced convection fin tube
condensing heat exchanger for supplying heat with an air pre-heater
having three tubes or several tubes according to yet another
embodiment.
DETAILED DESCRIPTION
[0044] Various embodiments of the present invention provide for an
improved heat exchanger that is configured to provide greater
efficiency. In some embodiments, the integral structure layout is
able to increase the heat exchanger efficiency. In some aspects the
heat exchanger has a counter flow design with two-stage heat
exchanger. The burner is on the top and the flue outlet on the
bottom. After burning, the combustion flue gas flows through the
group of fin tubes around the burner and flue baffles located
outside these tubes first, then it flows through the row of fin
tubes above the flue channel and the flue baffles under these
tubes. And then the flue gas flows out from the flue outlet along
the flue channel and counter flow with inlet air. The water inlet
is close to the flue outlet at the bottom, and the water outlet is
on the top of the heat exchanger. The water flows through inlet,
fin tubes, and the cavities connected to the upper and lower fin
tube bundles at both ends, such as front and rear water manifolds,
and then out from the outlet. The boiler water supply temperature
is higher than exhaust flue temperature by applying this type of
count flow structure. In this way, the heat transfer efficiency and
the amount of heat are both able to be increased.
[0045] In some aspects, the water baffles inside the rear water
manifold divide the rear water manifold into water inlet area and
outlet area. The water enters the small portion of circular fin
tubes bundle coaxed with burner and the row of fin tubes bundle
above the flue channel through water inlet area. These tubes are
called the secondary or condensing heat exchanger. The water
arrives at the front manifold, and then returns to the water outlet
area on the rear water manifold through the main portion of
circular fin tubes bundle, called the first or primary heat
exchanger. In such way, all fin tubes are the same. It is an
advantage of some embodiments described herein that the same key
components may be used to build heat exchangers in mass production,
decreasing the production difficulty and saving the production
cost. Meanwhile, examples described herein decrease the flame
temperature by controlling the distance between the flame and the
surface of the heat exchanger, which in turn reduce nitric oxide
(NOx) levels to below 30 parts per million (PPM).
[0046] The fin tubes with the bended fins, fabricated in an
additional process are able to increase the heat exchange
efficiency significantly in some aspects. The fin tube is as the
basic element in the forced convection condensing heat exchanger.
The heat transfer surface at flue side is increased by adding the
fins on the external of the heat exchanger tube. The enhanced heat
transfer at flue side increases the heat exchange efficiency, and
makes the whole heat exchanger smaller. By the additional
manufacturing process on the fins, for example bending, squeezing
or cutting, the distance between tubes could be made smaller.
Therefore, this makes flue gas have more contact with tubes, adds
gas flue turbulences, increase heat transfer and heat exchanger
efficiency, which in turn allows the heat exchanger to be made
smaller for a given heat exchange capacity.
[0047] There are flue baffles outside the circular fin tubes bundle
around the burner and flue baffles under the row of fin tubes
bundle. It is good to eliminate the "dead zone" on the flue path
and improve the flue distribution on the shell side. In some
aspects, the flue baffles force the flue gas flow along the fins
and cross bare tubes very closely, therefore, it enhance the heat
transfer, and improve flue flow distribution at the shell side. The
"dead zone" and "short circuit" at the flue flow path is decreased
very much.
[0048] Another additional device is the air pre-heater provided in
some examples. This air pre-heater can also increase the
efficiency. In some aspects, the air pre-heater is integrated
inside the flue channel of the heat exchanger. When the outdoor
temperature is below -20.degree. C. in the winter, the waste heat
in the flue warms the coming air. Meanwhile, it decreases the
exhaust flue temperature further, and the efficiency of the boiler
could reach 98% or more.
[0049] Preferred embodiments of the invention will now be further
described with reference to the drawing figures, in which like
reference numerals refer to like parts throughout. It should be
understood, however, that these figures are used to demonstrate and
explain the invention, but not to set the limitation to the
invention.
[0050] As shown in FIG. 1 to FIG. 16, the invention includes: Front
water manifold 1; front shell 2; shell 3; circular fin tubes bundle
4, flue baffles outside circular fin bundle 5, burner 6, flue
baffles under a row of fin tubes bundle 7, a row of fin tubes
bundle 8, rear water manifold 9, rear shell 10, air pre-heater 11,
flue exhaust 12, water outlet 13, water inlet 14, flue channel 15,
condensing water outlet 16, air inlet 17, water baffles 18.
[0051] Refer to FIG. 1 to FIG. 3; the invention describes one case
of a forced convection fin tube condensing heat exchanger for
supplying heat. As shown in FIGS. 1, 2 and 3, a forced convection
fin tube condensing heat exchanger for supplying heat includes
shell 3, burner 6, circular fin tubes bundle 4 and a row of fin
tubes bundle 8. There is an elliptic shell 3 which is welded with
two pieces of "U" type plates. The front shell 2 and rear shell 10
are welded to the elliptic shell. Two pieces of insulation plates
are installed inside the front shell 2 and rear shell 10.
[0052] As shown in the figures, there is the front water manifold 1
outside the front shell 2 and there is the rear water manifold 9
outside the rear shell 10. There is a water outlet 13 and a water
inlet 14 on the rear water manifold 9. And there is also a flue
exhaust 12 on the shell 3. The flues exhaust 12 is a 4-way
connector. It is the flue exhaust 12 on the top, condensate outlet
16 on the bottom, and the air inlet 17 of the air pre-heater 11 in
the middle.
[0053] FIG. 4 is the cross section view of an embodiment, which is
a forced convection fin tube condensing heat exchanger for
supplying heat. In this case, the forced convection fin tube
condensing heat exchanger for supplying heat includes shell 3,
burner 6 located inside the shell 3 and many fin tubes. There are
water inlet 14 and outlet 13 located on the rear water manifold 9,
and flue exhaust 12 on the shell 3. The burner 6 is connected to
the air and gas inlet mixer. The burner 6 is inside the shell 3 and
positioned on the top. A set of circular fin tubes bundle 4 is
around the burner 6 coaxially, and these tubes are tight close next
to each other. Both ends of the circular fin tubes bundle 4 and a
row of fin tubes bundle 8 are welded to the front shell 2 and rear
shell 10, as well as welded to the front water manifold 1 and rear
water manifold 9. There is a group of outer flue baffle 5 outside
the circular fin tubes bundle 4 which is around the burner 6. The
flue channel 15 is formed by the shell 3 and a row of fin tubes
bundle 8, and located below of the burner 6. The flue goes out from
the flue exhaust 12 through the flue channel 15. There is a group
of under flue baffles 7 located under the row of fin tubes bundle 8
inside in the flue channel 15.
[0054] At the two ends of the fin tubes bundle, there are front
water manifold 1 and rear water manifold 9. In the rear water
manifold 9, there are water baffles 18, which divides the rear
water manifold 9 into two parts, water inlet area and outlet
area.
[0055] If the circular distributed fin tubes have the same diameter
with the row of fin tubes which forms the flue channel 15, the
quantity of the fin tubes connected to the water inlet area is
roughly same as the quantity connected to the outlet area.
[0056] If the circular distributed fin tubes have the different
diameter with the row of fin tubes which forms the flue channel 15,
then the sum of the cross section area of the fin tubes connected
to the water inlet area roughly equals to the sum of the cross
section area of the fin tubes connected to the water outlet
area.
[0057] There are one or several cuboids' or cylindrical air
pre-heater tubes 11 inside the flue channel 15. The air pre-heater
11 connects air inlet after going through the flue channel 15. The
flue exhaust 12 is a 4-way connector. The flue exhaust 12 is on the
top, condensate outlet 16 is at the bottom, and the air inlet 17 is
located in the middle of the 4-way connector 12.
[0058] As shown in FIG. 5, it demonstrates the operation principle
of an embodiment, a forced convection fin tube condensing heat
exchanger for supplying heat. We can learn the following items from
this figure very clearly: the circular fin tubes bundle 4 is above
the row of fin tubes bundle 8, and they are in parallel; the burner
6, which connects the air and gas inlet, is installed inside the
circular fin tubes bundle 4 coaxially; under the circular fin tubes
bundle 4, the flue channel 15 is formed by the shell 3 and the row
of fin tubes bundle 8.
[0059] Two stage heat exchanging method is applied in an
embodiment. The heat exchanger uses the counter flow structure. The
high temperature flue flows downstream through fin tubes bundle 4
and a row fin tubes bundle 8. However, the water flow is opposite
to the direction of the flue. It goes through the row of fin tubes
bundle 8 firstly, and then the circular fin tubes bundle 4. The air
pre-heater 11 is located in the flue channel 15. The air gains the
heat from the flue further. Therefore, the temperature of the air,
which enters the combustion chamber, is increased; and at the same
time, the flue temperature can be further reduced.
[0060] In this case, the water flows through water inlet 14, front
water manifold 1, fin tubes, rear water manifold 9 and water outlet
13, and heated up through this circuit.
[0061] The water enters a small portion of the circular fin tubes
bundle 4 and the row of fin tubes bundle 8 through the water inlet
area, and arrives at the front water manifold 1. Then the water
flows to the water outlet area in the rear water manifold 9 through
the main portion of the circular fin tubes bundle 4. The same fin
tubes can be used by installing water baffle in the rear water
manifold and utilizing a portion of circular fin tubes bundle.
Therefore, the number of different parts is reduced. Of course, it
is okay not to utilize the small portion of the circular fin tubes
bundle. But, it may cause the negative impact to the size of the
whole heat exchanger, the diameter of the fin tubes, the structure
of the fin tubes bundles, the efficiency, and so on.
[0062] As shown in FIG. 6, it is the right view to demonstrate the
operation principle of an embodiment, a forced convection fin tube
condensing heat exchanger for supplying heat. In this case, the
flue channel 15 is formed by the lower part of the shell 3 and the
row of fin tubes bundle 8. A cuboid air pre-heater tube is set
inside. The water inlet tubes (first stage) include small portion
of the circular fin tubes bundle 4 and the entire row of fin tubes
bundle 8. The water outlet tubes (second stage) include the main
portion of the circular fin tubes bundle 4. If the circular fin
tubes have the same diameter with the row of fin tubes which forms
the flue channel 15, the quantity of the fin tubes for the water
inflow is same as the quantity of the fin tubes for the water
outflow.
[0063] FIGS. 7 and 8 are detailed views A and B of an embodiment.
As shown in FIG. 7, the outer flue baffles 5 are installed outside
the circular fin tubes bundle 4 by spot welding. The outer flue
baffles 5, which perfectly fit with the outside shape of the
circular fin tubes bundle, is a long striped "V" type plate with
radian cross section. The interfaces between fin tubes are
staggered with the gaps of the outer flue baffles 5.
[0064] As shown in FIG. 8, there are under flue baffles 7 located
at the bottom of the row of fin tubes bundle which forms the flue
channel 15. The under flue baffles 7, which cross section is "V"
type with radian, fit perfectly with the fin tubes. The interfaces
between the fin tubes are staggered with the gaps of the under flue
baffles 7.
[0065] The outer flue baffles 5 and under flue baffles 7 both guide
the flue flow directions.
[0066] FIGS. 9 and 10 are views of another embodiment which is the
sectional view of the forced convection fin tube condensing heat
exchanger for supplying heat with the burner 6 located at the lower
position. In this case, the burner 6 is at the lower part of the
shell 3. A set of circular fin tubes bundles 4 installed around the
burner 6 tightly and coaxially. The flue channel 15 which is formed
by the shell 3 and a row of fin tubes bundle 8 located above the
burner 6. The flue flows along the flue channel 15 to flue outlet
12. There are front water manifold 1 and rear water manifold 9 at
both ends of the fin tubes. There are water baffles 18 inside the
rear water manifold 9. The water baffles 18 divide the rear water
manifold 9 into water inlet area and outlet area. The water enters
the small portion of the circular fin tubes bundles and the entire
row of fin tubes bundle above the flue channel through water inlet
area, and arrives at the front water manifold 1. Then the water
flows back to the water outlet area at the rear water manifold 9
through the main portion of the circular fin tubes bundle.
[0067] The high temperature flue flows upstream and passes through
the circular fin tubes bundle 4, and the row of fin tubes bundle 8.
The air pre-heater 11 located inside the flue channel 15 exchange
heat with the flue.
[0068] FIG. 11 is the main view of the treated fin tube for the
circular fin tubes bundle in an embodiment. FIG. 12 is the side
view of the treated fin tube. In an embodiment, the fins are bended
or squeezed with 90 degree along with the tube axially, and two
bending lines also form some angle. The direction and angle of
bended fins can be adjusted appropriately according to the request
of the fin tubes arrangement. Referring to FIG. 6, the treated fin
tubes are arranged to form a circular fin tube bundle 4. According
to the specific production requirements, the manufacturing process
of bending or squeezing fins can be selected to reduce the distance
between the tubes next to each other.
[0069] FIG. 13 is the main view of the treated fin tube for the row
of fin tubes bundle. FIG. 14 is the side view of the treated fin
tube. In an embodiment, the fins are bended or squeezed with 90
degree along with the tube axially, and two bending lines are in
parallel. As shown in FIG. 6, the treated fin tubes are arranged to
form a row of fin tubes bundle 8.
[0070] FIG. 15 is the right side view of yet another embodiment,
which is a forced convection fin tube condensing heat exchanger for
supplying heat with two air pre-heater tubes. In this case: the
burner 6 is at the top of the shell 3, a set of circular fin tubes
bundle 4 installed around the burner 6 tightly, circularly and
coaxially. The flue channel 15 which is formed by the shell 3 and a
row of fin tubes bundle 8 is below the burner 6. The flue flows
along the flue channel 15 to flue outlet 12. In the mentioned flue
channel 15, there are two cuboid air pre-heater tubes 11. The air
pre-heater connects the air inlet device after going through flue
channel 15. There are front water manifold 1 and rear water
manifold 9 at the two ends of the fin tubes. There is water baffle
18 inside the rear water manifold 9, and it 18 divides the rear
water manifold 9 into water inlet area and outlet area. The water
enters the small portion of the circular fin tubes bundle 4 and the
entire row of fin tubes bundle 8 from water inlet area, and arrives
at the front water manifold 1. Then the water flows back to the
water outlet area at the rear water manifold 9 through the main
portion of the circular fin tube bundle.
[0071] FIG. 16 is the right side view of yet another embodiment,
which is a forced convection fin tube condensing heat exchanger for
supplying heat with three air pre-heater tubes. In this case: the
burner 6 is at the top of the shell 3, a set of circular fin tubes
bundle 4 installed around the burner 6 tightly, circularly and
coaxially. The flue channel 15 which is formed by the shell 3 and a
row of fin tubes bundle 8 is below the burner 6. The flue flows
along the flue channel 15 to flue outlet 12. In the mentioned flue
channel 15, there are three cuboid air pre-heater tubes 11. The air
pre-heater connects the air inlet device after going through flue
channel 15.
[0072] In conclusion, the purpose of some embodiments is to
increase the heat transfer area and improve the structure of the
heat transfer surface, therefore to increase heat exchange
efficiency. The heat exchanger uses the bended fin tube as the
basic element of the forced convection fin tube condensing heat
exchanger for supplying heat. It enhances the heat exchange on the
flue side and makes the whole heat exchanger smaller.
[0073] The flow of the flue is guided very close to the fins and
tubes with the application of the outer flue baffles 5 and the
under flue baffle 7. They improve shell side flue passes and
velocity distribution, therefore enhance heat exchange. The "dead
zone" and "short circuit" of the flue flow can be reduced very
much. The air pre-heater 11 is integrated into the heat exchanger
very clever. The wasted heat of the flue could warm the entered
cold air, and at the same time the flue is cold down further. When
the outdoor temperature is below -20.degree. C. in winter, the
efficiency could reach 98% or above.
[0074] Some key components are designed to be the same to minimize
the number of parts in an embodiment. This will help the mass
production, improve the manufacturing process and save the
cost.
[0075] It shall point out that the demonstration cases above are
only for explaining the technical schemes of the invention, not for
limiting them. Although the detailed explanations are listed with
only optimum cases in the invention, the technical persons in this
field shall know that the technical scheme can be modified and
replaced, but it does not separate from the spirit of the various
embodiments described herein, and shall be included in the scope of
the claims.
[0076] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
* * * * *