U.S. patent application number 14/001558 was filed with the patent office on 2013-12-12 for heat exchanger.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is Naoyuki Kamiyama, Tsuyoshi Miyachi, Takuya Okamoto, Yuichiro Sato. Invention is credited to Naoyuki Kamiyama, Tsuyoshi Miyachi, Takuya Okamoto, Yuichiro Sato.
Application Number | 20130327510 14/001558 |
Document ID | / |
Family ID | 46757570 |
Filed Date | 2013-12-12 |
United States Patent
Application |
20130327510 |
Kind Code |
A1 |
Kamiyama; Naoyuki ; et
al. |
December 12, 2013 |
HEAT EXCHANGER
Abstract
A heat exchanger is provided with a heat transfer tube bundle
housing duct for housing heat transfer tube bundles, openings
provided on a sidewall of the heat transfer tube bundle housing
duct, for freely inserting and removing the heat transfer tube
bundles, and rails provided in a direction perpendicular to an
inflowing direction of a flue gas G within the heat transfer tube
bundle housing duct, for freely moving the heat transfer tube
bundles. Since the heat exchanger can draw out only a specific heat
transfer tube bundle, it is possible to reduce a maintenance
period, thereby minimizing a regular inspection period.
Inventors: |
Kamiyama; Naoyuki; (Tokyo,
JP) ; Miyachi; Tsuyoshi; (Tokyo, JP) ;
Okamoto; Takuya; (Tokyo, JP) ; Sato; Yuichiro;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kamiyama; Naoyuki
Miyachi; Tsuyoshi
Okamoto; Takuya
Sato; Yuichiro |
Tokyo
Tokyo
Tokyo
Tokyo |
|
JP
JP
JP
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
46757570 |
Appl. No.: |
14/001558 |
Filed: |
November 10, 2011 |
PCT Filed: |
November 10, 2011 |
PCT NO: |
PCT/JP2011/075982 |
371 Date: |
August 26, 2013 |
Current U.S.
Class: |
165/172 |
Current CPC
Class: |
Y02E 20/363 20130101;
B01D 53/50 20130101; F28F 1/00 20130101; F28D 21/001 20130101; Y02E
20/30 20130101; F23J 15/08 20130101; F28D 7/1615 20130101; F28G
15/00 20130101; F23J 15/06 20130101; F28F 2280/00 20130101; F28F
2280/02 20130101; B01D 53/8625 20130101 |
Class at
Publication: |
165/172 |
International
Class: |
F28F 1/00 20060101
F28F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 28, 2011 |
JP |
2011-043313 |
Claims
1-5. (canceled)
6. A heat exchanger, comprising: a heat transfer tube bundle
housing duct for housing heat transfer tube bundles; openings
provided on a sidewall of the heat transfer tube bundle housing
duct, for freely inserting and removing the heat transfer tube
bundles; rails provided in a direction perpendicular to an
inflowing direction of a flue gas within the heat transfer tube
bundle housing duct, for freely moving the heat transfer tube
bundles; temporary support parts provided in a structure outside
the heat transfer tube bundle housing duct; moving rails supported
by the temporary support parts, for moving the heat transfer tube
bundles; and a driving apparatus for drawing out the heat transfer
tube bundles on the moving rails.
7. The heat exchanger according to claim 6, comprising:
bundle-bottom-rails provided in the openings, for drawing out and
moving the heat transfer tube bundles from a sidewall side in a
direction perpendicular to a flue gas direction within the heat
transfer tube bundle housing duct.
8. The heat exchanger according to claim 6, comprising:
bundle-bottom-rail provided in the openings, for drawing out and
moving the heat transfer tube bundles from the sidewall side in a
direction perpendicular to a flue gas direction within the heat
transfer tube bundle housing duct.
9. The heat exchanger according to claim 8, comprising: back rails
provided at back sides of the heat transfer tube bundles, the back
side coming in contact with the bundle-bottom-rail.
Description
FIELD
[0001] The present invention relates to a heat exchanger in an air
pollution control system.
BACKGROUND
[0002] As a general example of a system configuration, an air
pollution control apparatus of a boiler for thermal power plant or
chemical plant is disposed in order of denitrification equipment in
a flue gas flow channel, an air-preheater air heater, a heat
recovery unit of reheating gas-gas heater, a dry electronic
precipitator, wet desulfurization equipment, a reheating unit for
the gas-gas heater, and a chimney. Here, the gas-gas heater is
configured such that the heat recovery unit and the reheating unit
are connected to a cool and hot water circulating line to perform a
heat exchange with a flue gas through a circulating pump using
water as a medium.
[0003] In this control apparatus, the flue gas of the boiler is
guided to the air heater to be cooled to a temperature of, for
example, 130 to 150.degree. C. by exchanging heat with combustion
air and then is guided to the heat recovery unit of the gas-gas
heater to be further cooled. Thereafter, after the flue gas is
guided to the electronic precipitator to remove fly ashes, a
high-temperature flue gas in an outlet of the electronic
precipitator is further cooled to a low temperature by exchanging
heat with water and then is guided to the wet desulfurization
equipment. In the wet desulfurization equipment, SO.sub.2 contained
in the flue gas is absorbed and removed by absorbent which is
prepared by dissolving, for example, limestone in the form of
slurry and remaining fly ashes in the flue gas are also removed in
the gas-solution contact process. Then, the flue gas in which
SO.sub.2 and the fly ashes are removed is guided to the reheating
unit of the gas-gas heater. Here, the temperature of the flue gas
temperature-dropped by SO.sub.2 absorbent and the like in the
treatment process of the wet desulfurization equipment is raised by
the heat exchange with heat medium water passing through an
interior of a pipe disposed in the reheating unit of the gas-gas
heater. This causes functions of preventing white smoke generation
due to a reduction of the amount of water condensation and
improving diffusion efficiency due to temperature rise, when the
flue gas is released from the chimney to an atmosphere.
[0004] For example, a fin tube heat exchanger has been proposed as
a heat exchange method of large-scaled heat recovery unit and
reheating unit of the gas-gas heater in coal-fired power plant
(Patent Literature 1).
Citation List
Patent Literature
[0005] Patent Literature 1: Japanese Laid-open Patent Publication
No. 11-304138
SUMMARY
Technical Problem
[0006] In a case of performing maintenance of heat transfer bundles
in a heat exchanger, however, following problems occur.
[0007] 1) In a case where wear over time occurs due to blast effect
of combustion fly ashes to a heat transfer tube of a fin tube heat
exchanger in a thermal power plant, or in a case where the
composition of the same ashes has adhesive properties and corrosive
properties, the ashes are fixed to a heat transfer surface to
proceed corrosion of the heat transfer tube, a thickness of the
tube is decreased with time.
[0008] When an unplanned stop is caused by massive update or
maintenance of the bundles, damage of power sales occurs due to
inhibition of a commercial operation. For this reason, leakage of
heat medium water has been a very important issue.
[0009] 2) Further, the plant operation is stopped to repair in a
case where the number of leakage locations is large in leakage
inspection during operating or in a case where extensive repairs or
bundle updates are determined to be necessary.
[0010] 3) In the related art, in order to draw out a lower bundle,
large-scaled module bundles ranging from, for example, 20 to 30
tons per one bundle are lifted one by one in turns from an
upper-stage bundle by a crane from openings installed at an upper
part of a duct for storing the bundles of the heat exchanger.
[0011] Therefore, it is necessary to draw out even robust bundles
that do not require the maintenance.
[0012] Further, in case of requiring a bundle inspection work such
as, for example, a residual wall thickness inspection in the
interior of the duct, it is necessary to temporarily install an
entire-face scaffold on front and rear of all target bundles inside
the duct, and a large amount of cost and considerable period are
consumed for this.
[0013] 4) In this case, considerable period is required for a
massive repairs or updates of the bundles, and the damage of power
sales occurs due to the inhibition of the commercial operation
during existence of risks for delaying a regular inspection period
of the power plant.
[0014] 5) Further, in a case of performing the massive repair of
the lower-stage side bundle, it is necessary to temporarily place
the robust bundle in an open space until re-storing in the duct of
which the repair is completed. In this case, it is necessary to
ensure the period of this placed space, and the damage risk of the
placement space is also generated by curing deficiency depending on
weather environment when the temporary placement space is an
outdoor space.
[0015] In addition, there is a problem that management costs
increase even in a curing or an indoor storage.
[0016] The present invention has been achieved to solve the above
problems, and an object of the present invention is to provide a
heat exchanger that can draw out only a specific heat transfer tube
bundle to improve work efficiency.
Solution to Problem
[0017] According to a first aspect of the present invention in
order to solve the above-mentioned problems, there is provided a
heat exchanger, including: a heat transfer tube bundle housing duct
for housing heat transfer tube bundles; openings provided on a
sidewall of the heat transfer tube bundle housing duct, for freely
inserting and removing the heat transfer tube bundles; and rails
provided in a direction perpendicular to an inflowing direction of
a flue gas within the heat transfer tube bundle housing duct, for
freely moving the heat transfer tube bundles.
[0018] According to a second aspect of the present invention, there
is provided the heat exchanger according to the first aspect,
including: bundle-bottom-rails provided in the openings, for
drawing out and moving the heat transfer tube bundles from a
sidewall side in a direction perpendicular to a flue gas direction
within the heat transfer tube bundle housing duct.
[0019] According to a third aspect of the present invention, there
is provided the heat exchanger according to the first aspect,
further including: temporary support parts provided in a structure
outside the heat transfer tube bundle housing duct; moving rails
supported by the temporary support parts, for moving the heat
transfer tube bundles; and a driving apparatus for drawing out the
heat transfer tube bundles on the moving rails.
[0020] According to a fourth aspect of the present invention, there
is provided the heat exchanger according to the third aspect,
including: bundle-bottom-rail provided in the openings, for drawing
out and moving the heat transfer tube bundles from the sidewall
side in a direction perpendicular to a flue gas direction within
the heat transfer tube bundle housing duct.
[0021] According to a fifth aspect of the present invention, there
is provided the heat exchanger according to the fourth aspect,
including: back rails provided at back sides of the heat transfer
tube bundles, the back side coming in contact with the
bundle-bottom-rail.
Advantageous Effects of Invention
[0022] According to the present invention, since only a specific
heat transfer tube bundle can be drawn out, it is possible to
reduce a maintenance period, thereby minimizing a regular
inspection period.
BRIEF DESCRIPTION OF DRAWINGS
[0023] FIG. 1-1 is a schematic view of a heat exchanger.
[0024] FIG. 1-2 is a schematic view of the heat exchanger.
[0025] FIG. 2-1 is a perspective view illustrating schematically an
exterior of a heat exchanger according to a first embodiment.
[0026] FIG. 2-2 is a perspective view illustrating schematically
the exterior of the heat exchanger according to the first
embodiment.
[0027] FIG. 3 is a perspective view illustrating schematically an
exterior of a heat exchanger according to a second embodiment.
[0028] FIG. 4 is a schematic view illustrating main parts of FIG.
3.
[0029] FIG. 5 is a schematic view illustrating parts other than the
main parts of FIG. 3.
[0030] FIG. 6 is a schematic view of an air pollution control
system to which the heat exchangers according to the embodiments
are applied.
[0031] FIG. 7 is a schematic view of the heat exchanger of an air
pollution control installation.
DESCRIPTION OF EMBODIMENTS
[0032] Embodiments of the present invention will be described below
in detail with reference to the accompanying drawings. The present
invention is not limited to the following embodiments, but may be
constituted in combination with each of embodiments in case of
several embodiments. In addition, constituent elements in the
following embodiments include those that can be easily assumed by
persons skilled in the art or that are substantially
equivalent.
First Embodiment
[0033] FIG. 6 is a schematic view of an air pollution control
system to which heat exchangers according to the present embodiment
are applied.
[0034] In a process where a flue gas to be discharged from a boiler
101 of power plants, factories or the like is released from a
chimney 111, as illustrated in FIG. 6, an air pollution control
system 100 removes nitride oxide (NOx), soot dust, and sulfur oxide
(SOx) contained in the flue gas.
[0035] Firstly, a flue gas G.sub.o discharged from the boiler 101
is introduced into denitrification equipment 102 filled with a
catalyst. In the denitrification equipment 102, the nitrogen oxide
contained in the flue gas G.sub.0 is reduced to water and nitrogen
by ammonia (NH.sub.3) injected as a reducing agent to become
harmless.
[0036] A flue gas G.sub.1 discharged from the denitrification
equipment 102 is generally cooled to the temperature of 130.degree.
C. to 150.degree. C. through an air heater (AH) 103.
[0037] A flue gas G.sub.2 passed through the air heater 103 is
introduced into a heat recovery unit 104 serving as a heat
exchanger of gas-gas heater and then is heat-recovered by a heat
exchange with a heat medium (for example, water).
[0038] A temperature of a flue gas G.sub.3 passed through the heat
recovery unit 104 becomes approximately 85.degree. C. to
110.degree. C. to improve dust-collecting capability of an
electronic precipitator (EP) 105, for example.
[0039] The flue gas G.sub.3 passed through the heat recovery unit
104 is introduced into the electronic precipitator 105 and then the
shoot dust therein is removed.
[0040] A flue gas G.sub.4 passed through the electronic
precipitator 105 is pressurized by an air blower 106 to be driven
by an electric motor. In addition, the air blower 106 may not be
provided, or may be disposed on a downstream side of a reheating
unit 108 of the gas-gas heater.
[0041] A flue gas G.sub.5 pressurized by the air blower 106 is
introduced into desulfurization equipment 107. In the
desulfurization equipment 107, the sulfur oxide contained in the
flue gas G.sub.5 is absorbed and removed by an absorbent which is
prepared by dissolving limestone in a form of slurry, and gypsum
(not illustrated) is produced as a by-product. Then, the
temperature of a flue gas G.sub.6 passed through the
desulfurization equipment 107 is generally decreased to the extent
of about 50.degree. C.
[0042] The flue gas G.sub.6 passed through the desulfurization
equipment 107 is introduced into the reheating unit 108 serving as
the heat exchanger of the gas-gas heater. In a process where a heat
medium 83 is circulated while coming and going a pair of
circulating pipes 110 between the heat recovery unit 104 and the
reheating unit 108 by a circulating pump 109, the reheating unit
108 heats the flue gas G.sub.6 by recovery heat which is recovered
by the heat recovery unit 104. Here, the flue gas G.sub.6, which
has the temperature of about 50.degree. C., at an outlet of the
desulfurization equipment 107 is reheated to about 85.degree. C. to
110.degree. C. with the reheating unit 108, and then is released as
a flue gas G.sub.8 from the chimney 111 to an atmosphere.
[0043] FIG. 7 is a schematic view of a heat exchanger of an air
pollution control installation.
[0044] As illustrated in FIG. 7, the heat exchanger into which the
flue gas G.sub.2 is introduced to exchange heat with the heat
medium 83 is provided.
[0045] The heat exchanger has the circulating pipe 110 for
circulating the heat medium 83 between the heat recovery unit 104
and the reheating unit 108. The heat medium 83 is circulated
between the heat recovery unit 104 and the reheating unit 108
through the circulating pipe 110. A surface of the heat medium
circulating passage 110 provided in each of the heat recovery unit
104 and the reheating unit 108 is provided with a heat transfer
tube 11 on which a plurality of fins are provided. A heat
exchanging unit 86 is provided in the heat medium circulating
passage 110 to compensate energy, which is equivalent to
temperature drop absorbed by radiant heat when the heat medium 83
is circulated, by heating with a steam 87 and to be capable of
maintaining and adjusting a medium temperature of the heat medium
83.
[0046] The heat medium 83 is supplied to the heat medium
circulating passage 110 from a heat medium tank 88. The heat medium
83 is circulated in the circulating passage 110 by the heat medium
circulating pump 109. In addition, a supply quantity of the steam
87 is adjusted by an adjusting valve V.sub.1 according to the gas
temperature of the purified gas G.sub.6 from the desulfurization
equipment 107, the heat medium 83 to be fed into the reheating unit
108 is supplied to the heat recovery unit 104 by an adjusting valve
V.sub.2 according to the gas temperature of the flue gas G.sub.3
discharged from the heat recovery unit 104, and thus a supply
quantity of the heat medium 83 to be fed into the reheating unit
108 is adjusted. Further, the purified gas G.sub.7 discharged from
the reheating unit 108 is discharged from the chimney 111 to the
outside.
[0047] Hereinafter, the structure of the heat exchanger of the heat
recovery unit 104 and the reheating unit 108 according to the
present embodiment will be described with reference to drawings.
FIGS. 1-1 and 1-2 are a schematic view of the heat exchanger,
respectively.
[0048] As illustrated in FIGS. 1-1 and 1-2, the heat exchanger
includes a heat transfer tube bundle housing duct 20 in which a
plurality of heat transfer tube bundles, that is, a
high-temperature heat transfer tube bundle 22A, a
middle-temperature heat transfer tube bundle 22B, and a
low-temperature heat transfer tube bundle 22C are disposed from an
upstream side in an inflowing direction of the flue gas, the heat
transfer tube bundles being an aggregation which binds together the
heat transfer tube bundles.
[0049] Further, the plurality of heat transfer tube bundles 22A
(22A.sub.1 to 22A.sub.3) , 22B (22B.sub.1 to 22B.sub.3) , and 22C
(22C.sub.1 to 22C.sub.3) are disposed with a predetermined interval
to perform the heat recovery or the heat exchange in a gas flowing
direction of the flue gas. In FIG. 1, the flue gas G, a duct inlet
part 20a, and an expanded part 20b are illustrated. In addition, an
upstream side in a flue gas introducing direction of the heat
transfer tube bundle is a front 22a, and a downstream side in the
flue gas introducing direction is a rear 22b.
[0050] In drawings, an X-direction is the flue gas flowing
direction, a Y-direction is an insertion direction of the heat
transfer tube bundle, and a Z-direction is a stacked installation
direction of the heat transfer tube bundle.
[0051] FIGS. 2-1 and 2-2 are perspective views illustrating
schematically an exterior of the heat exchanger according to the
first embodiment.
[0052] The heat exchanger includes the heat transfer tube bundle
housing duct (hereinafter, referred to as a "bundle housing duct")
20 which houses heat transfer tube bundles 22, openings 26 which
are provided on a sidewall of the heat transfer tube bundle housing
duct 20 to freely insert and remove the heat transfer tube bundles
22, and bottom rails 27 which are provided in a direction
perpendicular to the inflowing direction of the flue gas G within
the bundle housing duct 20 to freely move the heat transfer tube
bundles.
[0053] Further, a reference numeral 25 indicates a handrail
provided in a framework stage through which persons come and go.
Generally, the handrail 25 is vertically stood so that persons do
not fall down, but is configured such that the bundles can pass
through, as illustrated in FIG. 2-1, since the handrail 25 is
provided with a hinge which is movable so as to recline in a
horizontal position at the time of taking the heat transfer tube
bundles 22 in and out.
[0054] Further, a floor 25a of the handrail is configured so as to
temporarily place the heat transfer tube bundles 22 when the
handrail 25 is reclined.
[0055] In drawings, the X-direction is the flue gas flowing
direction, the Y-direction is the insertion direction of the heat
transfer tube bundle, and the Z-direction is the stacked
installation direction of the heat transfer tube bundle.
[0056] In a case of specifying the number of leakage locations in a
leak test during an operation, the heat transfer tube bundle 20 is
set to be drawn out in following manners.
[0057] 1) In a case of drawing out a specified heat transfer tube
bundle (for example, heat transfer tube bundle 22C.sub.3), firstly,
the opening 26 is opened and the handrail 25 is reclined. 2) Then,
the heat transfer tube bundle 22C.sub.3, which is ranging from 20
to 30 tons per one bundle, is drawn out from the opening 25 while
being supported with a crane 23.
[0058] 3) The heat transfer tube bundles are lifted and temporarily
placed on a predetermined position using one crane (not
illustrated) when the entire heat transfer tube bundles are come
out of the openings 26.
[0059] Thus, an operation of drawing out the heat transfer tube
bundles from the stacked arrangement of each stage is
facilitated.
[0060] As a result, it is possible to independently draw out only
bundle requiring repair and renewal from each stage of the
stage-stacked bundle without drawing out another robust bundle.
[0061] At this time, since the bundle-bottom-rail 27 is installed
at a position corresponding to a lower part of each bundle in a
longitudinal direction inside the duct from a sidewall side to draw
out and move the bundle toward the opening, the heat transfer tube
bundle is easily drawn out in the longitudinal direction toward the
opening of the sidewall on the bundle-bottom-rail 27.
[0062] The heat transfer tube bundle loaded on the
bundle-bottom-rail 27 is drawn out in the longitudinal direction
by, for example, a chain block.
[0063] In the heat exchanger according to the present embodiment,
since only specified heat transfer tube bundle can be drawn out, it
is possible to shorten a maintenance period, resulting in
minimizing the regular inspection period.
[0064] In other words, in the related art, in order to draw out a
lower bundle, a useless work for drawing out even the robust bundle
of which the inspection is unnecessary needs to be performed, for
example, module bundles ranging from, for example, 20 to 30 tons
per one bundle are lifted one by one in turns from an upper-stage
bundle by the crane from the opening installed at an upper part of
the bundle housing duct for storing the bundle of the heat
exchanger, while the present invention can shorten time of about
40% with respect to replacement work of the bundle ranging
generally from 20 to 30 tons per one because of drawing out only
the specified heat transfer tube bundle.
[0065] In addition, since the bundle for requiring a repair is
independently drawn out, a location on which the robust bundle is
temporarily placed is unnecessary, and thus it is possible to cut a
cost by such amount and to also reduce a damage risk during the
temporary placement.
[0066] Further, in case of requiring a checking work of the heat
transfer tube bundle when a plant is stopped, since the inspection
is performed by drawing out only target bundle at a place having a
good working environment, temporary construction of an entire-face
scaffold in the duct is unnecessary and thus it is possible to cut
a cost by such amount and to shorten the period. Second
Embodiment
[0067] FIG. 3 is a schematic view of a heat exchanger according to
a second embodiment. FIGS. 4 and 5 are schematic views illustrating
main parts of FIG. 3. The same reference numerals can be denoted to
the same members as in the heat exchanger according to the first
embodiment and the description thereof will not be presented.
[0068] As illustrated in FIG. 3, the heat exchanger according to
the second embodiment includes a temporary support part 30 which is
detachably provided in a structure (framework) 21 outside the
bundle housing duct 20, a moving rail 31 which is supported by the
temporary support part 30 to move the heat transfer tube bundle 22,
a driving apparatus 32 which draws out the heat transfer tube
bundle 22 onto the moving rail 31, and a wire 33.
[0069] In the present embodiment, a back rail 28 is provided at a
portion which comes in contact with the bottom rail 27 of the heat
transfer tube bundle 22.
[0070] On the surface of the bottom rail 27 and the back rail 28,
thin plates 35A and 35B made of materials having a low friction
coefficient are provided, and the heat transfer tube bundle 22 is
easily drawn out while sliding the thin plates 35A and 35B.
[0071] Accordingly, the drawing-out is facilitated by the moving
rail 31 provided outside the bundle housing duct 20 and the driving
apparatus 32 such as a winch auxiliary mechanism capable of pulling
transversely the heat transfer tube bundle 22.
[0072] In order not to derail during the drawing-out, further, a
guide member 31a is provided on the moving rail 31.
[0073] In addition, an enclosure part 36 is provided at a lateral
face of the bottom rail 27, which is provided in the structure 21
inside the bundle housing duct 20, to prevent the mixing of
ashes.
[0074] At least two cranes are required for the first embodiment,
but the configuration of the present embodiment requires one crane.
Accordingly, it is possible to reduce a maintenance space by such
amount.
[0075] In addition, by selecting combinations of the materials
having the low friction coefficient for the thin plates 35A and
35B, the drawing-out and pushing are facilitated.
[0076] Here, examples of the combinations of the materials having
the low friction coefficient may include Cr (chrome plating)--Cu
(copper alloy) and SUS (bundle frame material)--Cu (copper
alloy).
[0077] Further, examples of preferable materials with respect to
sliding wear seizure may include a combination of steel (SUS)--hard
chrome plating, but are not limited thereto.
[0078] In addition, examples of a combination of materials having
corrosion resistance may include a combination of annealed
steel--SUS material, but are not limited thereto.
[0079] Further, since there is a possibility that soot dusts of
coal ash or fixing components are attached to the
bundle-bottom-rail 27, it may install a protective cover for the
bundle-bottom-rail to expose and move the bundle-bottom-rail 27 by
removing the cover after stopping the plant.
[0080] This can prevent inhibition of bundle maintenance work due
to ashes or fixing substances on the rail below the bundle.
[0081] In addition, the handrail 25 provided in the framework stage
through which persons come and go is vertically stood so that
persons do not fall down, but is configured such that the bundles
can pass through, as illustrated in FIG. 2-1, since the handrail 25
is provided with the hinge which is movable so as to recline in the
horizontal position at the time of taking the heat transfer tube
bundle 22 in and out.
[0082] As described above, according to the present invention,
since a construction period is significantly shortened in repair
and renewal constructions of a large-sized heat exchange bundle
after a rapid detection of the leakage locations of the heat medium
or during the regular inspection period of power plant, it is
possible to achieve an improvement of operation rate and thus to
achieve an increase of annual energy production of power.
[0083] Further, since a massive scaffold set is unnecessary, it is
possible to achieve a curtailment of the regular inspection period
of the bundle, a significant improvement of maintenance
workability, and a reduction of safety risk.
REFERENCE SIGNS LIST
[0084] 20 Heat Transfer Tube Bundle Housing Duct
[0085] 21 Structure
[0086] 22 Heat Transfer Tube Bundle
[0087] 23 Crane
[0088] 25 Handrail
[0089] 26 Opening
[0090] 27 Bottom Rail
[0091] 28 Back Rail
[0092] 31 Moving Rail
[0093] 31a Guide Member
[0094] 32 Driving Apparatus
[0095] 33 Wire
[0096] 35A, 35B Thin Plate
[0097] 36 Enclosure Part
* * * * *