U.S. patent application number 14/765070 was filed with the patent office on 2015-12-31 for cooling delta for a dry cooling system.
This patent application is currently assigned to GEA EGI Energiagazdalkodasi Zrt.. The applicant listed for this patent is GEA EGI ENERGIAGAZD LKOD SI ZRT.. Invention is credited to Csaba Bannerth, Gabor Csaba.
Application Number | 20150377559 14/765070 |
Document ID | / |
Family ID | 50555157 |
Filed Date | 2015-12-31 |
United States Patent
Application |
20150377559 |
Kind Code |
A1 |
Csaba; Gabor ; et
al. |
December 31, 2015 |
Cooling Delta For A Dry Cooling System
Abstract
The invention is a cooling delta for cooling liquids, gases or
vapours, said cooling delta comprising cooling panels arranged at
an angle relative to one another, in which cooling panels cooling
tubes are arranged, the cooling tubes extend horizontally or
substantially horizontally, and the cooling delta further
comprising a first media flow header being connected to the cooling
tubes at a junction of the cooling panels, and providing a flow
communication space for the cooling tubes, and second media flow
headers being connected to opposite ends of the cooling panels with
respect to the first media flow header, and providing a flow
communication space for the cooling tubes.
Inventors: |
Csaba; Gabor; (Budapest,
HU) ; Bannerth; Csaba; (Budakalasz, HU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GEA EGI ENERGIAGAZD LKOD SI ZRT. |
Budapest |
|
HU |
|
|
Assignee: |
GEA EGI Energiagazdalkodasi
Zrt.
Budapest
HU
|
Family ID: |
50555157 |
Appl. No.: |
14/765070 |
Filed: |
February 11, 2014 |
PCT Filed: |
February 11, 2014 |
PCT NO: |
PCT/HU2014/000016 |
371 Date: |
July 31, 2015 |
Current U.S.
Class: |
165/143 ;
165/144 |
Current CPC
Class: |
F28F 9/013 20130101;
F28D 1/0426 20130101; F28B 1/06 20130101 |
International
Class: |
F28D 1/04 20060101
F28D001/04; F28B 1/06 20060101 F28B001/06; F28F 9/013 20060101
F28F009/013 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 11, 2013 |
HU |
P1300085 |
Claims
1. A cooling delta for cooling liquid, gaseous or steam media, said
cooling delta comprising cooling panels arranged at an angle
relative to one another, in which cooling panels cooling tubes are
arranged, characterised in that the cooling tubes extend
horizontally or substantially horizontally, and the cooling delta
further comprises a first media flow header being connected to the
cooling tubes at a junction of the cooling panels, and providing a
flow communication space for the cooling tubes, and second media
flow headers being connected to respective opposite ends of the
cooling panels with respect to the first media flow header, and
providing a flow communication space for the cooling tubes.
2. The cooling delta according to claim 1, characterised in that
the first media flow header and/or the second media flow headers
are formed as columns.
3. The cooling delta according to claim 1, characterised by having
a reinforcing steel structure comprising the first media flow
header as an inside support column and the second media flow
headers as outside support columns, and by comprising fixed and/or
loose tube bundle sheets adapted for holding together the cooling
tubes.
4. The cooling delta according to claim 3, characterised in that
the tube bundle sheet receiving the cooling tubes is formed in the
support column, and the cooling tubes are welded or roll-pressed in
the bores of the support columns.
5. The cooling delta according to claim 3, characterised in that
chambers adapted for media inlet and media outlet are connected to
the cooling tubes extending through the bores or openings of the
support columns supporting the cooling tubes, the chambers being
disposed separately from the structures of the support columns.
6. The cooling delta according to claim 3, characterised in that
the cooling tubes are arranged in cooling columns, and the cooling
tubes are held together in the cooling columns by one or more fixed
or loose tube bundle sheets structurally separated from the support
columns, and the cooling columns, thereby forming separate assembly
units, are secured to the outside and inside support columns, and
flexible sealing material is disposed between respective flat,
bored surfaces formed on the support columns and the tube bundle
sheets holding together the cooling tubes.
7. The cooling delta according to claim 6, characterised in that
the tube bundle sheets, seals of resilient material, bracing screws
and optionally transition pieces are arranged at both ends of the
cooling columns, and that the cooling tubes disposed in the cooling
columns are removable together with the fixed and/or loose tube
bundle sheets holding them together without dismantling the outside
or inside support columns by displacing the cooling tubes in a
direction perpendicular to the tubes.
8. The cooling delta according to claim 6, characterised in that
resilient rubber sealing rings are arranged between tube bundle
sheets being arranged at both ends of the cooling columns, and
being loose and--at least at one end of the cooling columns--fixed,
connecting screws, transition pieces, and sealing surfaces of the
outside and inside support columns, and the cooling column is
displaceable either in the direction of the support column or in a
direction opposite to that by removing a loose tube bundle sheet
being arranged between the fixed tube bundle sheet and the flat
surface of the support column, and a transition piece being
removable sideways after loosening the attachment screws, and thus
the cooling column is removable, without dismantling the outside
and inside support columns, by displacing it first in a direction
perpendicular to the cooling tubes at the side opposite the fixed
tube bundle sheet and then at the side near the fixed tube bundle
sheet.
9. The cooling delta according to claim 1, characterised in that
means adapted for draining the cooling delta are connected to the
bottommost part of the inlet support column, and the cooling tubes
are arranged ascending from the support column adapted for
inletting the media towards the outlet support column.
10. The cooling delta according to claim 1, characterised in that
means adapted for draining the cooling delta are connected to the
bottommost part of the inlet support column, and the cooling tubes
(2) are arranged descending from the support column adapted for
inletting the media towards the outlet support column, and the
resistance of the cooling tubes (2) is chosen to be larger than the
hydrostatic pressure difference resulting from the height
difference between both ends of a cooling tube (2).
11. The cooling delta according to claim 1, characterized in that a
degassing means is connected to the uppermost part of the outlet
support column.
Description
TECHNICAL FIELD
[0001] The invention relates to a cooling delta applicable for a
dry cooling system.
BACKGROUND ART
[0002] It is known that dry cooling towers are frequently applied
for cooling the condensers of power plants. These cooling towers
include a large number of finned heat exchangers, providing very
high airside surface area. Most frequently, these heat exchangers
are installed along the circumference of the cooling tower, in a
so-called delta arrangement exemplified in FIGS. 1, 2 and 3. This
arrangement has the characteristic feature that the axis of the
cooling tubes 2 of the heat exchangers is vertical, the tubes being
arranged parallel with one another, along one or more planes in
so-called tube rows to form heat exchanger bundles 1. In order that
as many heat exchanger bundles 1 can be installed along the
circumference as possible, adjoining bundles are arranged at an
angle relative to each other, in a so-called delta arrangement. In
principle, such a solution may also be possible wherein the delta
angle is 180 degrees, i.e. the heat exchangers are arranged in a
single plane.
[0003] The deltas, of which each consists of two heat exchanger
bundles 1 arranged at an angle relative to each other, are
assembled by means of a common steel structure 8, each delta
thereby forming an individual assembly unit.
[0004] Inlet and outlet chambers 4, adapted for inletting and
outletting the medium to be cooled, are mounted at the bottom
portion of the heat exchanger bundles 1 installed in the delta, and
return chambers 5, adapted for reversing the flow direction of the
medium, are mounted at the top of the bundles.
[0005] This solution is satisfactory and efficient as long as the
water flow of the cooling tower does not exceed a critical limit
value.
[0006] This critical water flow value is determined by two factors.
One of these is the water-side resistance of the cooling tubes 2,
the other factor (closely related to the first one) is the inlet
velocity at which erosion may begin to occur at the cooling tube
inlets.
[0007] To better understand this, consider that the larger the
extracted thermal power is, the larger the water flow will be. In
proportion to the increasing thermal power, the air flow should
also increase, which goes hand in hand with the increasing combined
front surface area of the heat exchanger bundles 1 that have to be
built in. This increased front surface area may be provided by
increasing the circumference of the cooling tower, as well as the
height of the cooling column 7.
[0008] Assuming a twofold target increase of cooling power, it is
obtained--somewhat simplified--that in case the geometrical
proportions are kept, both the base diameter of the cooling tower
and the height of the cooling columns 7 should be increased by a
factor of 2.
[0009] Therefore, if the thermal load increases e.g. twofold, the
water flow also increases by the same amount.
[0010] From the above it follows that, since the area of the
cooling tower is increased only by a factor of 2, the water flow of
the heat exchangers at a given section of the circumference also
increases by a factor of 2. This, in turn, results in that the
velocity of water at the inlets of the heat exchangers--having a
height increasing 2 times with the increasing water flow--increases
2 times in proportion to the increasing cooling power.
[0011] According to our calculations, the critical inlet velocity
is reached in case of a conventional power plant of 500-700 MW, and
a nuclear power plant of 300-500 MW.
[0012] The tube velocity may of course be reduced by applying
multiple tube rows. This solution is, however, limited by the
increasing airside resistance of the heat exchanger, which in case
of natural draft necessitates an increase of tower height, and in
case of using fans the energy expenses of the self-consumption
increase.
[0013] The tube velocity may also be reduced by applying larger
diameter tubes, as illustrated in the top drawing of FIG. 2. This
solution also has its limits, namely that relative to the unit
front surface area of the heat exchanger bundle 1 an increasing
portion of the cross-section available for the free flow of air is
taken up by the larger-diameter cooling tubes 2. Thereby, in case
of natural draft, tower height is increased due to increasing air
resistance, while in case of using fans the energy consumption of
the tower is increased. Viewed from a different aspect, assuming
the air flow is kept constant, the horizontally measurable length
of the heat exchangers has to increase, which increases the
circumference of the tower.
[0014] It could also be possible to increase the number of the
applied cooling towers. However, this option is much more costly
compared to single-tower solutions.
[0015] It becomes apparent that, in case a single cooling tower is
applied, some provisions have to be made in case power is to be
further increased, since the above mentioned limitations may in
certain cases put in question the feasibility of indirect cooling
systems.
[0016] Returning now to the variant comprising a single cooling
tower having vertically arranged cooling deltas disposed along the
circumference in a conventional manner, two options suggest
themselves for solving the problem.
[0017] One of these options is known from prior art, namely that,
by vertically dividing the heat exchanger surface area of the tower
to two or more storeys, and increasing the number of the inlet and
outlet chambers 4, as well as of the return chambers 5, to twice or
multiple times the original, the height of the individual cooling
columns--and in proportion to that, their water load--is
reduced.
[0018] This solution has the disadvantage that, on the one hand, a
significant amount of ascending and descending distribution tubing
has to be installed, and, on the other hand, the number of the
inlet and outlet chambers 4 (arranged at the bottom), as well as of
the return chambers 5 (arranged at the top) increases in proportion
to the number of storeys.
[0019] This solution is based on the hitherto unquestioned
presupposition that the axis of the cooling tubes 2 has to be
arranged vertically.
DESCRIPTION OF THE INVENTION
[0020] The primary object of the invention is to provide a cooling
delta which are free of the disadvantages of the prior art
solutions to the greatest possible extent.
[0021] The objects of the invention can be achieved by the cooling
delta according to claim 1. Preferred embodiments of the invention
are defined in the dependent claims.
[0022] The cooling delta according to the invention is adapted for
cooling liquid, gaseous or steam media to be cooled (in the
following: media). The cooling delta according to the invention
comprises cooling panels arranged at an angle relative to one
another, in which cooling panels cooling tubes are arranged. In the
cooling delta according to the invention the cooling tubes extend
horizontally or substantially horizontally, the cooling delta
further comprises a first media flow header--arranged preferably
vertically or substantially vertically--being connected to the
cooling tubes at a junction of the cooling panels, and providing a
flow communication space for the cooling tubes, and second media
flow headers--arranged preferably vertically or substantially
vertically--connected to opposite ends of the cooling panels with
respect to the first media flow header, and providing a flow
communication space for the cooling tubes. The media flow headers
are preferably implemented as chambers. According to the invention,
the cooling tubes extend horizontally or substantially
horizontally, which is to be meant that the cooling tubes may have
a maximum inclination of a few degrees. In some embodiments, a
slight inclination is explicitly required; however, in conventional
cooling deltas the cooling tubes are arranged vertically, from
which the horizontal or substantially horizontal arrangement of the
cooling tubes is fundamentally different.
[0023] In an embodiment of the invention, the first media flow
header and/or the second media flow headers are formed as
columns.
[0024] In an embodiment of the cooling delta according to the
invention, loading forces arising from the weight of the cooling
columns and from wind load act on the outside and inside support
columns partly via the steel structure, and partly via the flat
surfaces of the support columns, which surfaces comprise openings
or bores and are adapted for holding together the cooling
tubes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Preferred embodiments of the invention are described below
by way of example with reference to the following drawings,
where
[0026] FIG. 1 is a drawing of a prior art cooling delta that has
heat exchanger bundles 1 and cooling columns 7, inlet and outlet
chambers 4 and return chambers 5, chamber stubs 6 and a steel
structure 8,
[0027] FIG. 2 shows a magnified view of a component of a prior art
cooling delta that has cooling tubes of two different diameters,
illustrating the cooling tubes 2 and cooling fins 3,
[0028] FIG. 3 shows a prior art multi-storey cooling delta
arrangement comprising distribution conduits 9,
[0029] FIG. 4 illustrates the delta arrangement according to the
invention, showing the inside support columns 10, the outside
support columns 11, and particularly in- and outlet, inlet, outlet
and return chambers for media flowing, all integrated in the
support column,
[0030] FIG. 5 shows magnified detail views of the media flow
chambers integrated in the inside support columns 10 and outside
support columns 11 arranged according to FIG. 4,
[0031] FIG. 6 shows a top plan view of the flow pattern that occurs
in a cross section of the delta in case of side wind,
[0032] FIG. 7 shows an embodiment of the delta arrangement
according to the invention, the deltas having cooling panels 19
arranged at two sides of the delta extending to the full height and
width thereof, cooling columns 7 arranged horizontally in the
cooling panels 19, inside support columns 10, outside support
columns 11, a steel structure 8, the drawing also showing arrows
indicating the flow direction of the media to be cooled,
[0033] FIG. 8 illustrates the interconnections applied in the
example of FIG. 7, showing cut out details of the horizontal
cooling column 7, the fixed tube bundle sheets 12 and loose tube
bundle sheets 13, 22, a transition piece 15, rubber rings 17, cut
out portions of the inside support columns 10 and outside support
columns 11 adapted for flowing the media, and, towards the bottom,
right- and left-side details of the cooling column illustrating the
different assembly and disassembly positions,
[0034] FIG. 9 shows exemplary connection options of the cooling
panels 19, and
[0035] FIG. 10 shows implementations of the tube bundle sheet
connections applying, respectively, rubber plates 26, and a
combination of rubber plates 26 and O-rings 17.
MODES FOR CARRYING OUT THE INVENTION
[0036] The solution according to the invention provides an
alternative of the prior art solutions (see FIGS. 4, 5, 6, 7, 9) by
arranging the cooling columns 1 and thereby the cooling tubes 2
horizontally, or substantially horizontally, while keeping the
advantageous vertical arrangement of the cooling delta. The ends of
tubes are passed through bores arranged on the vertical support
columns of the--otherwise necessarily applied--delta structure, and
are introduced into inlet and outlet chambers 4, or, without
applying these, directly into the inside support column 10 or
outside support column 11. In these solutions multiple horizontal
cooling columns 7, stacked above one another, constitute a cooling
panel 19. In the former case, the chambers 4, 5 may be arranged at
the other side (not shown) of the support columns, while in the
latter case they are formed integrated in the support columns 10,
11. In this latter case the bores receiving the cooling tubes are
disposed on the support columns 10, 11 themselves (see 14, FIG. 8),
and the support columns are implemented as enclosed structures.
This arrangement provides that the water flows through an enclosed
space into and out of the cooling tubes 2 of the heat exchanger
bundles 1.
[0037] While in conventional cooling deltas the length of the
cooling tubes reaches 25-30 m, in the cooling delta according to
the invention the tubes may be much shorter. The reduced tube
length involves reducing the flow speed of water in the heat
exchanger tubes, with the water side resistance also decreasing
according to the third power. The horizontal width of the heat
exchanger bundles built into conventional cooling deltas is 2.5-2.7
m. The bundles of the cooling delta according to the invention may
exceed that by a factor of 3 to 5.
[0038] The combination of these features allow that the 600-700 MW
power limit for single-tower dry cooling systems applied for
conventional power stations may be raised to 1200-1600 MW, also
allowing the application of the single-tower system for 800-1200 MW
PWR or BWR nuclear power station blocks.
[0039] The inventive solution has further important advantages,
namely that it reduces the sensitivity to wind and the danger of
freezing damage that conventional cooling towers having vertically
arranged tubes are subjected to. This may be understood
contemplating FIG. 6.
[0040] On a top sectional view of the delta, the flow pattern in
wind is shown for a cooling delta arranged at the side of the
tower. Since in the air flowing around the tower the wind speed
increases to twice the speed measurable further from the building
structures, according to the Bernoulli equation air pressure drops,
which results in a reduced air flow entering into these deltas.
However, this reduced air flow enters the air space of the delta at
high velocity at an oblique angle, and is distributed unevenly
along the width of the cooling columns 7. Thereby, the outside
portions 20 (from the perspective of the centre of the tower) of
the downwind cooling column 7 receive wind at high speed, while
other portions of the column receive wind at low speeds. The
outside corner of the cooling column 7 being in leeward is in a
vortex 27, with no or slight inflow, while further inside the space
of the delta the inflow speed is higher due to the stronger
vertices. As a result of that--assuming a vertically arranged tube
axis--the tubes situated at the outside portion 20 of the cooling
column shown in the right of the drawing may be overcooled, or, in
winter, may be damaged by freezing. This is related to the vertical
arrangement of the tubes, as the high air flow density affects the
entire length of the cooling tubes in question. The same holds for
the cooling tubes 2 situated in the inside portion 21 of the
left-side cooling column. Conversely, due to the depression, the
cooling tubes 2 of the outside portion of the upwind column provide
little or no cooling. As a result of the uneven airflow
distribution illustrated above, the heat exchanger tubes are prone
to freezing damage, and, in addition to that, the cooling power of
the cooling tower is also reduced, which poses problems of
operation especially in case of winds occurring in the hottest
summer period.
[0041] The situation is completely different in the case of the
horizontal tube arrangement implemented according to the invention.
Referring also to FIG. 6, at the outside portion of the cooling
panel 19, consisting of multiple horizontal cooling columns 7 shown
in the right of the drawing, freezing damage cannot occur due to
the high air flow density because, on the one hand, the water
flowing in from the direction of the outside support column 11 is
still warm, and, on the other hand, because the high air flow
density occurs only at a relatively short section of the cooling
tube 2. The more intensive cooling which occurs at the inside
portion of the left-side cooling panel 19 also does not pose any
danger, because the effect occurs only at a relatively short
longitudinal section of the cooling tubes of the horizontal heat
exchanger bundle 1 rather than along the full length of the tubes,
as is the case with the vertical cooling tube arrangement. On the
other hand, because the water cools down to a relatively smaller
extent in the vicinity of the outside support column 11 of this
particular cooling panel 19, it enters the critical inside portion
21 at a relatively warm. It may also be conceived that in case of
the solution according to the invention all cooling tubes 2
situated at a given side of a cooling panel 19 have almost
identical cooling effect. The temperature of outlet water is less
uneven than in case of the conventional solution applying
vertically arranged cooling tubes. As a result of that, on the
whole all cooling deltas have better cooling power than in case of
the conventional solution, i.e. wind deteriorates cooling power to
a lesser extent.
[0042] Since the suggested dimensions and weight of the cooling
deltas is several times bigger than that of conventional deltas,
and no suitable lifting equipment is available any more after
construction is completed, it would not be possible to dismount and
remove a completed cooling delta. Therefore, it should be provided
for that the heat exchangers built into the deltas may be removed
in smaller units. The invention also contains provisions, explained
below, addressing this problem.
[0043] The deltas illustrated in FIG. 7 have two cooling panels 19
arranged at an angle relative to each other and facing to each
other. Parallelly arranged, horizontally extending cooling columns
7 are arranged in the cooling panels 19. The cooling columns 7
consist of one or more heat exchanger bundle 1 or bundles connected
to each other (the attachments are not shown in themselves). The
heat exchanger bundle 1 is the smallest heat exchanger assembly
unit of the cooling column 7, i.e. the smallest unit to which the
column may be disassembled without cutting. The cooling columns 7,
consisting of one or more interconnected heat exchanger bundle 1 or
bundles 1, can be integrally removed from the delta. The cooling
column has the same width as the cooling components, and its width
cannot be further reduced without cutting. The cooling columns 7
are manufactured by joining at least one end of each cooling tube 2
to a tube bundle sheet (or tubesheet) made from continuous plates
applying rolling, welding, or any other technology that produces
permanent joints. The major constituent parts of the steel
structure 8 adapted for supporting the cooling delta are the
three--vertical or substantially vertical--inside 10 and outside
support columns 11 situated in the three corners of the delta. The
surfaces of the support columns facing the cooling columns are
machined flat to form flat walls 14, and are configured to comprise
bores arranged in a pattern corresponding to the arrangement of the
cooling tubes 2 in the heat exchanger bundle 1. The flat wall 14
constitutes either a flat surface or the tube bundle sheet itself
through which the media flows to and from the cooling tubes 2. A
plurality of cooling columns 7 are connected to each support column
pair made up of an inside support column 10 and an outside support
column 11. The bored flat walls 14 of the corresponding inside
support columns 10 and outside support columns 11 are arranged
parallel with each other. The steel structure 8 of the delta, and
thereby the inside and outside support columns 10, 11, are fixedly
secured. This constraint has to be borne in mind when producing the
cooling columns 7 so as to allow them to be removed from between
the inside and outside support columns 10, 11.
[0044] A possible embodiment of the invention is presented as
follows. A solution extensively applied in conjunction with dry
cooling towers is sealing the ends of the cooling tubes 2 by means
of rubber rings 17. Such a solution is shown in FIG. 8, in the
groove extending between the loose tube bundle sheet 13, the flat
wall 14, and the cooling tube 2. The primary advantage of this
solution is that the costly welding-in process of the cooling tubes
2 may be omitted. Another advantage is that it is capable of
simultaneously sealing the gaps between the cooling tube 2 and the
loose tube bundle sheet 13 and between the loose tube bundle sheet
13 and the flat wall 14 (in this case, the support column wall).
This sealing solution also allows--and it has not been applied so
far--that the loose tube bundle sheet 13 situated at the end
portion of the heat exchanger may be inserted in place loosely,
without rolling. This allows that a fully installed cooling column
may be pulled out from the flat wall 14, i.e. in the present case
from the bores of the flat wall 14 formed integrally with the
support column 18, in a direction parallel with the tube axis. All
that has to be done is to loosen the tube bundle sheet screws 16
joining the tube bundle sheets.
[0045] This, however, would not be sufficient to provide for the
removability of the cooling columns if axial displacement were not
allowed at the other side of the column (shown in the right side in
FIG. 8). To allow the cooling columns to be removed, the following
solution may be applied. It is obvious that the cooling tubes 2 of
the cooling blocks of the heat exchanger should be arrested in the
longitudinal direction in at least one plane perpendicular to the
tubes. To achieve that, it is imperative that the cooling tubes 2
are rolled or welded into a fixed tube bundle sheet 12 on at least
one side. One end of the cooling column 7 is therefore configured
accordingly. The axial displaceability of the cooling tubes 2 is
provided for by extending the end of the cooling tubes 2 over the
tube bundle sheet to the required extent. Since the cooling column
7 must be fixed in the axial direction, for which the rubber rings
are not sufficient, a fixed connection must be provided between the
fixed tube bundle sheet 12, disposed at this end of the cooling
column 7 and adapted to fixedly engage the tubes, and the flat wall
14 formed on the support column. In addition to that, it should
also be provided that, in case this fixed connection is loosened,
the free tube ends of the cooling column 7 may be slid into the
inside support column 10 through the bores thereof adapted for
receiving the cooling tubes 2. This is achieved by applying the
following solution:
[0046] A loose tube bundle sheet 13, adapted for receiving in a
non-fixed manner the cooling tube ends extending over the fixed
tube bundle sheet 12, is placed on the tube ends of the cooling
column. Rubber rings 17 are placed on the distal side of the loose
tube bundle sheet, on the ends of the cooling tubes 2. In the
assembled state, the rubber rings 17 situated between the loose
tube bundle sheet 13 and the flat wall 14 functioning as the
sealing surface of the inside support column 10 are constricted by
inserting such transition pieces 15 between the fixed tube bundle
sheet 12 and the loose tube bundle sheet 13 that are resilient, but
fixed enough to transfer a pressure force to the loose tube bundle
sheet 13 that is sufficient to provide the required sealing effect
by deforming the rubber rings 17. In case this transition piece 15
is removed, and the fixed tube bundle sheet 12 is pressed against
the flat wall 14 functioning as the sealing surface of the inside
support column 10 by tightening the tube bundle sheet screws 16,
the cooling column 7 may be longitudinally displaced towards the
inside of the inside support column 10 by an extent corresponding
to the thickness of the transition piece 15. To achieve that, all
that has to be done is to loosen the screws 23 of the loose tube
bundle sheet 22 situated at the opposite side. The thickness of the
transition piece 15 is chosen such that on the other side the ends
of the cooling tubes 2 may come out from bores of the outside
support column 11. After that, provided that the tube bundle sheet
screws 16, 23 are removed at both sides, the cooling column 7 may
be removed by first lifting it at the--now freed up--side facing
the outside support column 11, and then pulling and lifting it out
at the side facing the inside support column 10. To allow for that,
the spatial steel structure of the delta (not shown) is configured
such that the side through which the damaged cooling columns 7 are
to be removed is free, or arranged to be able to be freed up.
[0047] A major advantage of this solution should be mentioned here,
i.e. that this sealing and tube bundle sheet attachment method does
not require high manufacturing accuracy. It is not important that
the flat walls 14 of the inside and outside support columns 10, 11,
being adapted for sealing, fall perfectly in the same plane. It is
also not a problem if the sealing flat walls 14 of the respective
inside and outside support columns 10, 11 facing each other are not
perfectly parallel, and there can even be an angle allowance in
their perpendicular angle relative to the cooling tubes 2. There
can also be difference in the distances between the sealing flat
walls 14 of the inside and outside support columns 10, 11. What is
important is the positional accuracy of the bores disposed on the
cooling columns, and the bores of the tube bundle sheets 12, 13,
14, but this requirement is not different from requirements set for
conventional heat exchangers.
[0048] The connections between the cooling tubes 2 and the inside
and outside support columns 10, 11 may be implemented as welded
connections. In that case, the components designated by reference
numerals 12, 13, 15, 16, 17, 22, 23 in FIG. 8 may be omitted.
Damaged cooling tubes 2 may only be repaired in this case by
destructively dismantling those surfaces of the corresponding
inside and outside support columns 10, 11 that are situated facing
the axes of the cooling tubes 2. At the end the repair operation,
the dismantled support column must be reconstructed. This may be
carried out by closing the previously cut out opening by
welding.
[0049] Another possible embodiment of the invention is illustrated
in the top drawing of FIG. 10. In this embodiment, the fixed tube
bundle sheets 12 of the cooling column 7 are connected at both ends
of the cooling column 7 to the machined flat walls 14 of the inside
and outside support columns 10, 11 by means of a respective sealing
rubber plate 26.
[0050] The above described solution may also be realised (see the
drawing at the bottom of FIG. 10) by for instance applying the
latter rubber plate solution at the left-side connection, and the
arrangement including rubber rings 17 shown in the right in FIG. 8
at the right-side connection. The cooling column may be dismantled
from the structure also in this case.
[0051] The circuit connection options of the heat exchangers
implemented according to the invention are not different from those
of conventional heat exchangers; full cross-flow being the simplest
to implement. In this case, the medium to be cooled flows in the
same direction in all of the tubes of a given cooling column.
According to the examples illustrated in FIGS. 4, 5, 6 the cooling
water inlet is at the outside support column 11 of the deltas,
while the cooled down water is let out at the inside support column
10. A reversed solution may also be possible, but, as it was shown
in the above discussion on the danger of freezing damage, the
former solution is more advantageous.
[0052] Further connection options may also be carried out, some of
these embodiments being shown in FIG. 9. The top left drawing of
the figure illustrates the connection scheme of the embodiment
described in relation to FIG. 7.
[0053] An alternative arrangement is also possible (top right
drawing, FIG. 9) wherein for instance only the flow direction of
the cooling water is changed at the inside support column 10, and
the inlet and outlet are disposed on the two outside columns. In
this case, each two adjoining cooling columns are connected
serially on the water side.
[0054] In a further possible solution (bottom left drawing) that
one of the support columns is divided in two by a divider member 24
along a plane perpendicular to the longitudinal axis of the column,
while the opposite column is left undivided. Thereby, two flow
paths may be configured along the column's axis by installing inlet
and outlet stubs on only the divided columns but not on the
opposite ones, which latter columns therefore become adapted for
only reversing the flow direction of the media. By including
multiple vertical divisions, more than two flow paths may also be
formed.
[0055] Applying a longitudinal division 25 to the inside support
columns 10 in a direction parallel with their axis, a
cross-counter-flow connection of the cooling columns may also be
realised, as it is shown in the bottom right drawing in FIG. 9. In
this solution, the outside support columns 11 may function as the
common return chamber of the cross-counter-flow cooling panel 19
having separate inlets through the two inside support columns. Of
course, a similar solution may be provided by implementing the
double water conduction in the outside support column 11. This may
also be realised by arranging the water inlets and outlets
exclusively at the bottom of the structure.
[0056] A solution for filling and draining the cooling deltas
should also be found which provides that air can flow out from the
cooling tubes during filling and water can flow out therefrom
during draining. This may be achieved by raising to a small extent
the axis of the cooling tubes 2 (seen from the direction of the
inlet support column). The same effect may be obtained for instance
by disposing the bores of the inside support column 10 a few
centimeters higher, which is allowed by the resilient sealing
method described above. According to this solution, the draining
ports of the cooling delta are disposed at the bottommost portion
of the inlet support columns.
[0057] Such an arrangement is also possible wherein the cooling
tubes 2 descend towards the direction of oufflowing air (taking
into account the filling direction). In this case, the draining
means is disposed at the bottommost portion of the outlet support
column. In such an embodiment, the hydraulic resistance of the
cooling tube 2 must exceed the hydrostatic pressure difference
caused by the height difference resulting from the tube's
inclination.
[0058] In case of this example, the media enters the outside
support column 11 at the bottom, and is let out at the top of the
inside support column 10. The deltas are filled also in this
direction, such that air is let out at the top portion of the
inside support column 10. Draining may be carried out in the
opposite direction.
[0059] The invention is, of course, not limited to the preferred
embodiments described in details above, but further variants,
modifications and developments are possible within the scope of
protection determined by the claims.
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