U.S. patent application number 16/068221 was filed with the patent office on 2019-01-10 for sectional heat exchanger for use in a heat cell.
This patent application is currently assigned to BEKAERT COMBUSTION TECHNOLOGY B.V.. The applicant listed for this patent is BEKAERT COMBUSTION TECHNOLOGY B.V.. Invention is credited to Harshit GUPTA, Omke Jan TEERLING, Raymond WESTERS.
Application Number | 20190011149 16/068221 |
Document ID | / |
Family ID | 55527341 |
Filed Date | 2019-01-10 |
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United States Patent
Application |
20190011149 |
Kind Code |
A1 |
GUPTA; Harshit ; et
al. |
January 10, 2019 |
SECTIONAL HEAT EXCHANGER FOR USE IN A HEAT CELL
Abstract
A sectional heat exchanger for a condensing heat cell comprises
two end segments and one or more than one intermediate segment(s).
The one or the more than one intermediate segment(s) and the two
end segments are assembled in the heat exchanger. A combustion
chamber is provided in the sectional heat exchanger. Each of the
one or the more than one intermediate segment(s) comprises at least
one water flow channel for water to be heated. Between each two
consecutive segments at least one flue gas flow channel is
provided, extending from the combustion chamber. The one or the
more than one intermediate segment(s) each comprise a horizontal
row of ribs extending into the flue gas flow channel in order to
increase heat exchange from the flue gas to the water to be heated.
Ribs at the two outer sides of the horizontal row of ribs have a
larger height than ribs in the middle of the row of ribs. With
height of the rib is meant the dimension of the rib in the vertical
direction of the sectional heat exchanger. The more than one
intermediate segment(s) each comprise a plurality of rows of pins
extending in the flue gas channel to increase heat transfer.
Inventors: |
GUPTA; Harshit; (KL
Groningen, NL) ; WESTERS; Raymond; (RS Nieuwe Pekela,
NL) ; TEERLING; Omke Jan; (PG 't Harde, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BEKAERT COMBUSTION TECHNOLOGY B.V. |
AR Assen |
|
NL |
|
|
Assignee: |
BEKAERT COMBUSTION TECHNOLOGY
B.V.
AR Assen
NL
|
Family ID: |
55527341 |
Appl. No.: |
16/068221 |
Filed: |
March 3, 2017 |
PCT Filed: |
March 3, 2017 |
PCT NO: |
PCT/EP2017/055036 |
371 Date: |
July 5, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24H 9/0026 20130101;
F24H 1/32 20130101 |
International
Class: |
F24H 1/32 20060101
F24H001/32; F24H 9/00 20060101 F24H009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2016 |
EP |
16159385.0 |
Claims
1. A sectional heat exchanger for a condensing heat cell, wherein
the sectional heat exchanger comprises two end segments and one or
more than one intermediate segment(s) provided between the two end
segments; wherein the one or the more than one intermediate
segment(s) and the two end segments are assembled in the heat
exchanger, wherein a combustion chamber is provided in the
sectional heat exchanger, wherein each of the one or the more than
one intermediate segment(s) comprises at least one water flow
channel for water to be heated, wherein in between each two
consecutive segments at least one flue gas flow channel is
provided, and wherein the flue gas flow channel extends from the
combustion chamber, wherein the one or the more than one
intermediate segment(s) each comprise a horizontal row of ribs
extending into the flue gas flow channel in order to increase heat
exchange from the flue gas to the water to be heated; wherein ribs
at the two outer sides of the horizontal row of ribs have a larger
height than ribs in the middle of the row of ribs; wherein with
height of the rib is meant the dimension of the rib in the vertical
direction of the sectional heat exchanger; wherein the one or the
more than one intermediate segment(s) each comprise a plurality of
rows of pins extending in the flue gas channel to increase heat
transfer.
2. A sectional heat exchanger as in claim 1, comprising a first
section of the water flow channel located below the combustion
channel; wherein at least some ribs in the middle of the row of
ribs only partially overlap in height direction the height of the
first section of the water flow channel located below the
combustion chamber.
3. A sectional heat exchanger as in claim 1, wherein the distance
between ends in the flue gas channel of ribs of the row of ribs and
ends of ribs positioned on the opposing segment is less than 4
mm.
4. A sectional heat exchanger as in claim 1, wherein the row of
ribs comprises ribs of a first height and ribs of a second height,
wherein the first height is larger than the second height; and
wherein ribs at the outer sides of the horizontal row of ribs are
ribs of the first height; and wherein ribs in the middle of the row
of ribs are ribs of the second height.
5. A sectional heat exchanger as in claim 1, wherein the
intermediate segment(s) comprise a first horizontal row of pins
below the row of ribs, wherein the pins extend into the flue gas
flow channel, wherein this row of pins comprises at its two outer
sides pins extending into the flue gas flow channel so that a
distance of less than 4 mm is created with pins extending from the
opposed segment into the flue gas shaft; wherein this row of pins
comprises in its middle pins extending into the flue gas shaft so
that a distance of more than 10 mm is created with pins extending
into the flue gas shaft from the opposed segment.
6. A sectional heat exchanger as in claim 5, wherein the
intermediate segment(s) comprise a plurality of horizontal rows of
pins below the row of ribs, wherein the pins extend into the flue
gas flow channel, wherein each row of pins comprises at its two
outer sides pins extending into the flue gas flow channel so that a
distance of less than 4 mm is created with pins extending from the
opposed segment into the flue gas shaft; wherein each row of pins
comprises in its middle pins extending into the flue gas shaft so
that a distance of more than 10 mm is created with pins extending
into the flue gas shaft from the opposed segment.
7. A sectional heat exchanger as in claim 1, wherein the combustion
chamber has perpendicular to its length axis a cylindrical shape
with a circular cross section.
8. A sectional heat exchanger as in claim 1, wherein the water flow
channel in the intermediate segment runs over at least 80% of the
circumference of the combustion chamber around the combustion
chamber.
9. The sectional heat exchanger as in claim 1, wherein the
sectional heat exchanger comprises at least two intermediate
segments and wherein the at least two intermediate segments are
provided parallel to each other in the sectional heat
exchanger.
10. The sectional heat exchanger as in claim 1, wherein in the
intermediate segment(s), the water flow channel follows a
meandering flow path.
11. The sectional heat exchanger as in claim 1, wherein the
sectional heat exchanger comprises more than one intermediate
segment and wherein water flow channels of the more than one
intermediate segment are connected in parallel flow connection.
12. The sectional heat exchanger as in claim 1, wherein the water
flow channels in the one or in the more than one intermediate
segment(s) are provided for counter flow of the water with respect
to the flow direction of the flue gas channels.
13. A heat cell, comprising a sectional heat exchanger as in claim
1; and a burner, wherein the burner is provided in the combustion
chamber for the production of flue gas to flow in parallel through
the flue gas channels between the segments of the sectional heat
exchanger.
14. A heat cell as in claim 13, wherein the burner extends
perpendicularly to the one or to the more than one intermediate
segment(s).
Description
TECHNICAL FIELD
[0001] The invention relates to the field of sectional heat
exchangers for use in a heat cell. Such heat exchangers comprise
several segments. When assembling the sectional heat exchanger, the
number of segments is selected as a function of the required
capacity of the sectional heat exchanger. More specifically, the
sectional heat exchanger of the invention has a combustion chamber
in which a burner can be installed--thereby forming a heat
cell--for the generation of flue gas that will transfer its thermal
energy to heat water. Such heat cells can be used in boilers.
BACKGROUND ART
[0002] Sectional heat exchangers are built up of a number of
sections or segments. Sectional heat exchangers, e.g. out of
aluminium, exist that comprise a number of identical intermediate
segments positioned next to each other; and two end segments. The
number of intermediate segments that is used in the assembly of the
heat exchanger depends on the required capacity of the heat
exchanger. The heat exchanger has a number of channels--at least
one channel in each intermediate segment--in parallel flow
connection for water to be heated, and flue gas channels extending
from the one or more than one combustion chambers in the heat
exchanger.
[0003] A sectional heat exchanger, using cast intermediate
segments, is provided in DE102005014616B3, in which one single
burner can be mounted in the one combustion chamber of the
sectional heat exchanger.
[0004] GB2441183A discloses a heat exchanger for use in a
condensing boiler comprising a plurality of heat exchanger sections
having at least one internal flow passage with an inlet and an
outlet for the passage of a heat exchange medium and a plurality of
elongate fins on at least one side of each section defining flue
gas flow channels, a burner to produce hot flue gas, a means to
guide the flue gas from the burner through the flow channels from a
primary part to a secondary part of the heat exchanger, and a means
to promote unidirectional flue gas flow before entering the primary
part. Promotion means may be a U-shaped barrier that changes the
flue gas from a radial to the unidirectional flow and also changes
from a downward to an upward flow. The promotion means may comprise
a plurality of elongated fins disposed between, and parallel to,
vertical arms of the U-shape.
DISCLOSURE OF INVENTION
[0005] The primary object of the invention is to provide sectional
heat exchangers that are less prone to boiling when used in heat
cells for boilers.
[0006] The first aspect of the invention is a sectional heat
exchanger for a condensing heat cell. The sectional heat exchanger
comprises two end segments and one or more than one intermediate
segment(s) provided between the two end segments. The one or the
more than one intermediate segment(s) and the two end segments are
assembled in the heat exchanger. A combustion chamber is provided
in the sectional heat exchanger, preferably perpendicular to the
one or to the more than one intermediate segment(s). Each of the
one or the more than one intermediate segment(s) comprises at least
one water flow channel for water to be heated. In between each two
consecutive segments between two intermediate segments if more than
one intermediate segment is provided as well as between
intermediate segments and end segments--at least one flue gas flow
channel is provided, extending from the combustion chamber. As a
consequence, flue gas can flow from the combustion chamber into the
flue gas flow channels of the sectional heat exchanger. The one or
the more than one intermediate segment(s) each comprise a
horizontal row of ribs extending into the flue gas flow channel in
order to increase heat exchange from the flue gas to the water to
be heated. Ribs at the two outer sides of the horizontal row of
ribs have a larger height than ribs in the middle of the row of
ribs. With height of the rib is meant the dimension of the rib in
the vertical direction of the sectional heat exchanger. The more
than one intermediate segment(s) each comprise a plurality of rows
of pins extending in the flue gas channel to increase heat
transfer. Preferably, each row of pins is provided in serial flue
gas flow direction. Preferably the pins have a circular cross
section.
[0007] Preferably, the rib has a substantially rectangular cross
section, with its largest side aligned in the vertical direction of
the heat exchanger. More preferably, the substantially rectangular
cross section is a rectangular cross section having rounded
edges.
[0008] The sectional heat exchanger of the invention has the
surprising benefit that boiling of water in the water flow channels
is prevented. This benefit is believed to be achieved thanks to the
modified heat exchange at the horizontal row of ribs because of the
differences of height of the ribs. The lower height of the ribs in
the middle of the row of ribs will obviously involve a reduced heat
transfer, negative for efficiency of the heat exchanger.
[0009] Preferably, the intermediate segment is provided such that
parallel flows of flue gas flow along all of the ribs of the
horizontal row of ribs. Meant is that no gas flow flows first along
one rib of the horizontal row of ribs and then in serial flow
arrangement along another rib of the horizontal row of ribs.
[0010] Preferably, the height over width ratio of each of the ribs
of the horizontal row of ribs is more than 2.
[0011] In a preferred embodiment, the one or the more than one
intermediate segment(s) each comprise only one row of ribs
extending into the flue gas flow channel in order to increase heat
exchange from the flue gas to the water to be heater.
[0012] Preferably, the sectional heat exchanger is a condensing
heat exchanger.
[0013] In a preferred heat exchanger, ribs in the middle of the row
of ribs have less than 70% --more preferably less than 55%--of the
height of the ribs at the two outer sides of the horizontal row of
ribs.
[0014] Preferably, the two end segments each comprise a horizontal
row of ribs extending into the flue gas flow channel in order to
increase heat exchange from the flue gas to the water to be heated.
Ribs at the two outer sides of the horizontal row of ribs have a
larger height than ribs in the middle of the row of ribs. With
height of the rib is meant the dimension of the rib in the vertical
direction of the sectional heat exchanger. In a more preferred
embodiment, the two end segments each comprise only one row of ribs
extending into the flue gas flow channel in order to increase heat
exchange from the flue gas to the water to be heated.
[0015] Preferably the one or the more than one intermediate
segment(s) and/or the two end segments are aluminium or aluminium
alloy segments, preferably separate segments.
[0016] Preferably the one or the more than one intermediate
segment(s) and/or the two end segments are cast segments,
preferably separate cast segments.
[0017] In a preferred embodiment, the sectional heat exchanger
comprises at least two intermediate segments; and the at least two
intermediate segments are provided parallel to each other in the
sectional heat exchanger.
[0018] In a preferred heat exchanger, at least some ribs in the
middle of the row of ribs only partially overlap in height
direction the height of the first section of the water flow channel
located below the combustion chamber. With the first section of the
water flow channel located below the combustion chamber is meant
the elongated full width section of the water flow channel
immediately below the combustion channel. Such embodiment has shown
to synergistically contribute to reduced risk of boiling of water
in the water flow channel.
[0019] In a preferred embodiment, the distance between ends in the
flue gas channel of ribs of the row of ribs and ends of ribs
positioned on the opposing segment is constant for all ribs in the
row of ribs.
[0020] Further synergistic effects are obtained by a sectional heat
exchanger in which the distance between ends in the flue gas
channel of ribs of the row of ribs and ends of ribs positioned on
the opposing segment is less than 4 mm, and preferably less than 3
mm. Preferably the distance between ends in the flue gas channel of
each of the ribs of the row of ribs and ends of ribs positioned on
the opposing segment is less than 4 mm, and preferably less than 3
mm. More preferably, the distance between ends in the flue gas
channel of ribs of the row of ribs and ends of ribs positioned on
the opposing segment is constant for all ribs in the row of
ribs.
[0021] In a preferred heat exchanger, the row of ribs
comprises--and preferably consists out of--ribs of a first height
and ribs of a second height. The first height is larger than the
second height. Ribs at the outer sides of the horizontal row of
ribs are ribs of the first height. Ribs in the middle of the row of
ribs are ribs of the second height. More preferably, all other ribs
than the ribs of the first height are ribs of the second height.
Even more preferably, less than 60% of the ribs of the row of ribs
are ribs of the first height. Even more preferable, less than 40%
of the ribs of the row of ribs are ribs of the first height. In a
preferred embodiment, the ribs of a second height have less than
70%--more preferably less than 55%--of the height of the ribs of a
first height.
[0022] Preferably, the intermediate segment(s) comprise a first
horizontal row of pins below the row of ribs, wherein the pins of
the first horizontal row of pins extend into the flue gas flow
channel. With first horizontal row of pins is meant the horizontal
row of pins immediately below the row of ribs. This row of pins
comprises at its two outer sides pins extending into the flue gas
flow channel so that a distance of less than 4 mm and preferably
less than 3 mm--is created with pins extending from the opposed
segment into the flue gas shaft. This row of pins comprises in its
middle pins extending into the flue gas shaft so that a distance of
more than 10 mm--and more preferably of more than 20 mm--is created
with pins extending from the opposed segment into the flue gas
shaft. Such embodiments contribute synergistically to the
prevention of boiling of water in the water flow channel. In a more
preferred embodiment, below the first horizontal row of pins,
further horizontal rows of pins extending into the flue gas channel
are provided. Preferably within such horizontal row of pins, the
distance between the pin and the pin extending into the glue gas
flow channel from the opposed segment is constant over the width of
the horizontal row of pins.
[0023] Preferably, the intermediate segment(s) comprise a plurality
of horizontal row of pins below the row of ribs, wherein the pins
of the horizontal rows of pins extend into the flue gas flow
channel. Each of these rows of pins comprises at its two outer
sides pins extending into the flue gas flow channel so that a
distance of less than 4 mm and preferably less than 3 mm--is
created with pins extending from the opposed segment into the flue
gas shaft. These rows of pins comprise in their middle pins
extending into the flue gas shaft so that a distance of more than
10 mm--and more preferably of more than 20 mm--is created with pins
extending from the opposed segment into the flue gas shaft. Such
embodiments contribute synergistically to the prevention of boiling
of water in the water flow channel.
[0024] In a more preferred embodiment, additional horizontal rows
of pins extending into the flue gas channel are
provided--preferably below the plurality of rows of pins that
extend over different length in the flue gas channel. Within such
additional horizontal row of pins, the distance between the pin and
the pin extending into the glue gas flow channel from the opposed
segment is constant over the width of the horizontal row of
pins.
[0025] Preferably, the combustion chamber has perpendicular to its
length axis a cylindrical shape with a circular cross section.
[0026] Preferably, the water flow channel in the intermediate
segment runs over at least 80% --and more preferably over at least
90%--of the circumference of the combustion chamber around the
combustion chamber.
[0027] Preferably, the sectional heat exchanger comprises at least
two intermediate segments. The at least two intermediate segments
are provided parallel to each other in the sectional heat
exchanger.
[0028] Preferably, in the intermediate segment, the water flow
channel follows a meandering flow path.
[0029] A preferred sectional heat exchanger comprises more than one
intermediate segment. Water flow channels of the more than one
intermediate segment, and preferably also of the two end segments,
are connected in parallel flow connection.
[0030] Preferably, the water flow channels in the one or in the
more than one intermediate segment(s) are provided for counter flow
of the water with respect to the flow direction of the flue gas
channels.
[0031] A second aspect of the invention is a heat cell. The heat
cell comprises a sectional heat exchanger as in the first aspect of
the invention; and a, preferably one, more preferably only one,
burner, preferably a premix gas burner, and preferably a
cylindrical burner, provided in the combustion chamber for the
production of flue gas to flow in parallel flow connection through
the flue gas flow channels between the segments of the heat
exchanger. The burner is preferably mounted so that it extends in
the combustion chamber perpendicularly to the one or to the more
than one intermediate segment(s).
[0032] Preferably, the heat cell has a condensation sump at the
bottom of the heat cell.
BRIEF DESCRIPTION OF FIGURES IN THE DRAWINGS
[0033] FIG. 1 shows a heat cell according to the second aspect of
the invention, comprising a sectional heat exchanger according to
the first aspect of the invention.
[0034] FIG. 2 shows a view on an intermediate segment of a
sectional heat exchanger according to the invention.
[0035] FIG. 3 shows a cross section along plane III-Ill of an
intermediate segment of the heat exchanger of FIG. 1.
MODE(S) FOR CARRYING OUT THE INVENTION
[0036] FIG. 1 shows a heat cell according to the second aspect of
the invention, comprising a condensing sectional heat exchanger
according to the first aspect of the invention. The figure shows a
section 100 perpendicularly to the segments of the sectional heat
exchanger. FIG. 2 shows a view on an intermediate segment of a
sectional heat exchanger according to the invention. FIG. 3 shows a
cross section along plane III-Ill of an intermediate segment of the
heat exchanger of FIG. 1.
[0037] The exemplary sectional heat exchanger of FIGS. 1, 2 and 3
comprises two end segments 102, 104 and two intermediate segments
106 provided between the two end segments 102, 104. The two
intermediate segments and the two end segments are cast aluminum
parts and are assembled in the heat exchanger. A cylindrical
combustion chamber 108, 208, 308 with a circular cross section is
provided in the sectional heat exchanger, in the example
perpendicular to the intermediate segments and perpendicular to the
end segments. A cylindrical gas premix burner 110 is provided in
the combustion chamber, perpendicular to the intermediate segments
and perpendicular to the end segments.
[0038] Each of the intermediate segments 106 and each of the end
segments 102, 104 comprise a water flow channel 112, 312 for water
to be heated. Water flow channels of the intermediate segments, and
preferably also of the two end segments, are connected in parallel
flow connection. The water flow channels in the intermediate
segments and in the end segments follow a meandering flow path
through the segment. The water flow channels in the intermediate
segments as well as the water flow channels in the end segments run
over more than 90% of the circumference of the combustion chamber
around the combustion chamber. The water channels are provided for
counter flow compared to the flue gas flow direction in the flue
gas flow channels.
[0039] In between each two consecutive segments at least one flue
gas flow channel 114 is provided, extending from the combustion
chamber 108, 208, 308. The intermediate segments 106 as well as
both end segments 102, 104--each comprise a horizontal row of ribs
116, 216 extending into the flue gas flow channel in order to
increase heat exchange from the flue gas to the water to be heated.
Ribs 218 at the two outer sides of the horizontal row of ribs have
a larger height than ribs 220 in the middle of the row of ribs. In
the example, the intermediate segments 106 and the two end segments
102, 104 each comprise only one row of ribs 116, 216 extending into
the flue gas flow channel in order to increase heat exchange from
the flue gas to the water to be heated. In the example, the ribs
have a substantially rectangular cross section, with their largest
side aligned in the vertical direction of the heat exchanger. In
the exemplary heat exchanger shown in FIGS. 1-3, the ribs 220 at
the middle of the row of ribs of the intermediate segments as well
as the ribs at the middle of the row of ribs of the end segments
have 66% of the height of the ribs 218 at the two outer sides of
the horizontal row of ribs. In another exemplary heat exchanger,
the ribs 220 at the middle of the row of ribs of the intermediate
segments as well as the ribs at the middle of the row of ribs of
the end segments have 50% of the height of the ribs 218 at the two
outer sides of the horizontal row of ribs.
[0040] In an exemplary heat exchanger, ribs in the middle of the
row of ribs only partially overlap in height direction the first
section of the water flow channel located below the combustion
chamber.
[0041] In the example shown in FIGS. 1-3, the distance between ends
in the flue gas channel of each of the ribs of the row of ribs and
ends of ribs positioned on the opposing segment is 2 mm.
[0042] The intermediate segments as well as the end segments
comprise a first horizontal row of pins 132, 232 below the row of
ribs. These pins extend into the flue gas flow channel. This row of
pins 132, 232 comprises at its two outer sides pins extending into
the flue gas flow channel so that a distance of less than 4 mm and
preferably less than 3 mm--is created with pins extending into the
flue gas shaft from the opposed segment. This row of pins comprises
in its middle pins extending into the flue gas shaft so that a
distance of 28 mm is created with pins extending from the opposed
segment into the flue gas shaft.
[0043] Below the first horizontal row of pins, further horizontal
rows of pins 140, 240 extending into the flue gas channel are
provided. In the exemplary heat exchanger, the distance between the
pin and the pin extending into the glue gas flow channel from the
opposed segment is constant over the width of the horizontal row of
pins. In a further exemplary heat exchanger, each of the segment(s)
comprises a plurality of horizontal row of pins below the row of
ribs, wherein the pins of the horizontal rows of pins extend into
the flue gas flow channel. Each of these rows of pins comprises at
its two outer sides pins extending into the flue gas flow channel
so that a distance of less than 4 mm and preferably less than 3
mm--is created with pins extending from the opposed segment into
the flue gas shaft. These rows of pins comprise in their middle
pins extending into the flue gas shaft so that a distance of more
than 20 mm is created with pins extending from the opposed segment
into the flue gas shaft.
* * * * *