Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
SCAFFOLD APPARATUS FOR OPERATIONS ON INNER WALL SURFACE OF TOWER
STRUCTURE AND OPERATIONAL METHOD FOR INNER WALL SURFACE USING
THE SAME
TECHNICAL FIELD
The present invention relates to a scaffold apparatus for
conducting operations on an inner wall surface of a tower
structure, used for conducting a variety of operations on the
inner wall surface of a tall tower structure with a blast furnace
type structure, such as the digester provided in a paper
production plant, as well as an operational method for an inner
wall surface using such a scaffold apparatus.
BACKGROUND ART
Generally, in a tower structure, maintenance is essential
in ensuring retention of the tower functions over an extended
period, and the inner wall surface of the tower in particular
is exposed to severe temperature and pressure conditions, or
a corrosive environment of chemicals or the like, and
consequently frequent maintenance operations such as
inspections, cleaning, modifications and welding must be
undertaken.
However, a tower structure is tall, and the operational
target zone extends over a wide height range, from regions near
the bottom of the tower to regions near the top, and because
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the operations on the inner wall surface of such a tower
structure require both operators and a variety of operational
materials, an operations scaffold must be put up inside the tower
structure. Conventionally, the most typical method of
assembling this type of operations scaffold has usually involved
assembling a scaffold framework inside the tower, and then
providing an operations footing on top.
However, accordingto this operations scaffoldassembling
method using a scaffold framework, each time the operating
height is altered, a level adjustment operation requiring the
addition of further scaffold framework is required, and
consequently the operating efficiency is extremely poor, and
because these level adjustment operations are conducted at
considerable height, problems also arise regarding the safety
of the actual level adjustment operation itself.
Accordingly, an object of the present invention is to
provide a scaffold apparatus for conducting operations on an
inner wall surface of a tower structure, which enables
operations on the inner wall surface of the tower structure to
be conducted safely and with good operability, as well as an
operational method that utilizes such a scaffold apparatus.
DISCLOSURE OF THE INVENTION
A scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to a first aspect
of the present invention comprises either a single post or a
plurality of posts put up inside a tower structure from a bottom
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section thereof toward a top section, and a height adjustable
operations platform that is attached to the posts in a manner
of freely movable in up or down direction.
By using this type of construction, a scaffold apparatus
for conducting operations on an inner wall surface of a tower
structure according to the first aspect of the present invention
comprises either a single post or a plurality of posts put up
inside a tower structure from a bottom section thereof toward
a top section, and a height adjustable operations platform that
is attached to the posts in a manner of freely movable in up
or down direction, and consequently, putting up the posts inside
the tower structure and then attaching the height adjustable
operations platform means that when any of a variety of
operations are conducted on the inner wall surface of the tower
structure, adjustments of the installation height of the height
adjustable operations platform withinthe towerstructure (that
is, the height position at which operations are conducted using
theheight adjustable operationsplatform) are performed easily
and quickly by moving the height adjustable operations platform
up or down along the posts. As a result, compared with a
conventional case in which, for example, a level adjustment
operation such as adding to the scaffold framework is required
inside the tower structure every time the operating height is
altered, the operability of inner wall surface operations
improves markedly, and because level adjustment operations need
not be conducted at great heights, the safety of the operations
also improves, meaning both operating cost reductions and
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improved safety are achieved.
Furthermore, a second aspect of the present invention is
the scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to the first aspect
of the present invention, wherein the posts are put up by
sequentially stacking and connecting a plurality of posts pieces,
which are of dimensions that enable transport through a
materials transport port provided in the tower structure, from
the bottom section of the tower structure toward the top section.
By using this type of construction, a scaffold apparatus
for conducting operations on an inner wall surface of a tower
structure according to this second aspect of the present
invention offers the following characteristic effects in
addition to the effects provided by the first aspect of the
invention. Namely, in the scaffold apparatus for conducting
operations on an inner wall surface of a tower structure
according to this aspect of the present invention, the posts
are put up by sequentially stacking and connecting a plurality
of posts pieces, which are of dimensions that enable transport
through a materials transport port provided in the tower
structure, from the bottom section of the tower structure toward
the top section, and consequently, even though the operation
must be conducted under the restricted operational space
conditions unique to tower structures, a post of any height is
put up easily by carrying the required number of post pieces
into the tower structure and then sequentially combining the
pieces. As a result, the scaffold apparatus is applied to inner
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wall surface operations within a variety of different tower
structures of different heights, enabling an improvement in the
general-purpose applicability of the scaffold apparatus.
In addition, a third aspect of the present invention is
the scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to either of the
first or second aspects of the present invention, wherein the
bottom end of each post is supported by a lower support base,
which is secured immediately above a tower bottom section via
securing pieces provided on the side wall of the tower structure
immediately above the tower bottom section.
By adopting these types of features, a scaffold apparatus
for conducting operations on an inner wall surface of a tower
structure according to this third aspect of the present
invention offers the following characteristic effects in
addition to the effects provided by the first and second aspects
of the invention. Namely, in the scaffold apparatus for
conducting operations on an inner wall surface of a tower
structure according to this aspect of the present invention,
the bottom end of each post is supported by a lower support base
secured immediately above a tower bottom section via a securing
piece provided on the side wall of the tower structure
immediately above the tower bottom section, and consequently
the entire weight, including the dead load of the posts and the
attached height adjustable operations platform, and the weight
of any operators and/or operating materials loaded onto this
height adjustable operations platform, is supported directly
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by the side walls at a point immediately above the tower bottom
section of the tower structure, via the aforementioned lower
support base, and the application of load onto the tower bottom
section is avoided.
As a result, compared with the case in which the entire
weight of the aforementioned posts and the like is supported
by the tower bottom section of the tower structure, that is,
the region that is typically constructed from an end plate with
a curved surface, the weight of the posts and the like is
supported more reliably and in a more stable manner, and both
the reliability of the installation of the posts and the like,
and the reliability of the various operations conducted using
the posts and the attached height adjustable operations platform,
are improved.
In addition, because the tower bottom section of the tower
structure has the end plate structure described above, that
section is more complex and more expensive to produce than the
side wall section, and consequently by not needing to use this
tower bottom section as the support site for the posts and the
like, damage to the tower bottom section is effectively avoided,
resulting in an improvement of the durability of the tower
structure, or a reduction of the production costs.
Furthermore, a fourth aspect of the present invention is
the scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to the first aspect
of the present invention, wherein the height adjustable
operations platform is a knockdown structure that is capable
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of being transported through a materials transport port provided
in the tower structure.
By using this type of construction, a scaffold apparatus
for conducting operations on an inner wall surface of a tower
structure according to this fourth aspect of the present
invention offers the following characteristic effects in
addition to the effects provided by the first aspect of the
invention. Namely, in the scaffold apparatus for conducting
operations on an inner wall surface of a tower structure
according to this aspect of the present invention, the height
adjustable operations platform is a knockdown structure that
is capable of being transported through a materials transport
port provided in the tower structure, and consequently even
though the operation must be conducted under the restricted
operational space conditions unique to tower structures, a
height adjustable operations platform having any of a variety
of different shapes (namely, a shape that corresponds with the
internal dimensions of the target tower structure) is assembled
easily by carrying the disassembled members into the tower
structure and then sequentially combining the members, and as
a result, the scaffold apparatus become applied to inner wall
surface operations within a variety of different tower
structures of different internal dimensions, enabling an
improvement in the general purpose applicability of the scaffold
apparatus.
Furthermore, a fifth aspect of the present invention is
the scaffold apparatus for conducting operations on an inner
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wall surface of a tower structure according to the fourth aspect
of the present invention, wherein the height adjustable
operations platform is equipped with elevation drive means that
enables the platform to be raised and lowered under its own power,
and the external periphery of the height adjustable operations
platform is equipped with guide wheel units that are provided
with a wheel, which displaces freely toward, and away from, the
inner wall surface of the tower structure and is held in
continuous contact with the inner wall surface by a
predetermined pressure.
By using this type of construction, a scaffold apparatus
for conducting operations on an inner wall surface of a tower
structure according to this fifth aspect of the present
invention offers the following characteristic effects in
addition to the effects provided by the fourth aspect of the
invention. Namely, in the scaffold apparatus for conducting
operations on an inner wall surface of a tower structure
according to this aspect of the present invention, the height
adjustable operations platform is equipped with elevation drive
means that enables the platform to be raised and lowered under
its own power, and the external periphery of the height
adjustable operations platform is equipped with guide wheel
units that are provided with a wheel, which displaces freely
toward, and away from, the inner wall surface of the tower
structure and is held in continuous contact with the inner wall
surface by a predetermined pressure.
Accordingly, in a scaffold apparatus for conducting
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operations on an inner wall surface according to this aspect
of the present invention, because the height adjustable
operations platform is capable of being raised and lowered under
its own power, during various operations using the height
adjustable operations platform, adjustments to the height of
the height adjustable operations platform is performed easily
and quickly, for example in accordance with the requirements
of an operator, and consequently both the operability and
mobility are good, meaning the operating efficiency of
operations that are conducted using the height adjustable
operations platform is improved markedly.
In addition, in this scaffold apparatus for conducting
operations on an inner wall surface of a tower structure, because
the height adjustable operations platform is equipped with the
aforementioned guide wheel units, the following types of effects
are achieved:
(1) the wheels of the guide wheel units are held in continuous
contact with the inner wall surface by a predetermined pressure,
and as a result of the bracing action provided by these wheels,
sideways swinging during raising or lowering of the height
adjustable operations platform is largely inhibited, enabling
a more stable, smoother movement, and improving the safety
during movement;
( 2 ) in those cases in which an operator on the height adjustable
operations platform performs an operation using any of a variety
of operating materials, with the height adjustable operations
platform secured at a predetermined height position, the bracing
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action of the wheels of the guide wheel units prevents sideways
rolling of the height adjustable operations platform, and
ensures good safety on the height adjustable operations platform
during operations; and
5 (3) because the wheels of the guide wheel units displace freely
toward, and away from, the inner wall surface of the tower
structure, even if, for example, there are irregularities along
the height direction (that is, in the direction of movement for
the height adjustable operations platform) of the tower
10 structure (for example, even if there are sections in which the
internal diameter dimension of the tower structure changes),
by utilizing the aforementioned displacement function, the
wheels easilyrideoversuch irregularities, and irregularities
and the like in the inner wall surface cause absolutely no
impediment to the movement of the height adjustable operations
platform, and as a result, stable vertical movement of the height
adjustable operationsplatform is achieved, meaning the general
purpose applicability of the scaffold apparatus for conducting
operations on the inner wall surface of tower structures of a
variety of constructions is improved even further.
In addition, an operational method for an inner wall
surface according to a sixth aspect of the present invention
comprises the steps of loading people and/or an operating
material onto a height adjustable operations platform, which
is attached to a single post or a plurality of posts put up inside
a tower structure from a bottom section thereof toward a top
section in a manner that enables free up or down movement along
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the posts, and adjusting the operating height by moving the
height adjustable operations platform up and down along the
posts, while performing the required operations on the inner
wall surface of the tower structure.
By using this type of operational method, in an operational
method for an inner wall surfaces of a tower structure according
to the sixth aspect of the present invention, people and/or
operating materials are loaded onto a height adjustable
operations platform, which is attached to a single post or a
plurality of posts put up inside a tower structure from a bottom
section thereof toward a top section in a manner that enables
free up or down movement along the posts, and the operating
height is adjusted by moving the height adjustable operations
platform up and down along the posts, while the required
operations are performed on the inner wall surfaces of the tower
structure, and consequently, compared with a conventional case
in which, for example, a level adjustment operation such as
adding to the scaffold framework is required inside the tower
structure every time the operating height is altered, the
operating efficiency of inner wall surface operations improves
markedly, and because level adjustment operations need not be
conducted at great heights, the safety of the operations also
improves, meaning operations realizes both cost reductions and
improvement of safety.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG.l is a cross-sectional view of a tower structure
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showing the operational state when a scaffold apparatus for
conducting operations according to the present invention is used
to perform any of a variety of operations on the inner wall
surface of a digester.
FIG.2 is an enlarged view of the height adjustable
operations platform section shown in FIG.1.
FIG.3 is a view along the arrow headed line III-III of
FIG.1.
FIG.4 is an enlarged perspective view of the section IV
shown in FIG.3.
FIG.5 is an enlarged cross-sectional view along V-V of
FIG.3.
FIG. 6 is an enlarged view along the arrow headed line VI-VI
of FIG. 1 .
FIG.7 is an enlarged view along the arrow headed line
VII-VII of FIG.1.
FIG.8 is an enlarged view along the arrow headed line
VIII-VIII of FIG.7.
FIG. 9 is an enlarged view of the section IX shown in FIG. 7.
BEST MODE FOR CARRYING OUT THE INVENTION
As follows is a description of a scaffold apparatus for
conducting operations and an operational method according to
the present invention, using the case of a C02 blast cleaning
operation of the inner wall surface of a digester (tower
structure) with a blast furnace type structure employed in a
paper production plant as an example.
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FIG. 1 shows a digester 1, with a scaffold apparatus for
operations, which is used for conducting a cleaning operation
of the inner wall surface, erected therein.
A: Configuration of the Digester 1
The digester 1 is, for example, a large scale, tall, closed
vessel with an internal diameter of 4 to 5 meters and a height
of 40 to 50 meters, and is classified as a type-1 pressure vessel
in the safety standards. Accordingly, the state of the inner
wall surface must be inspected for safety purposes, and where
necessary, required inner wall surface repair operations, such
as the repair, by welding, of reduced thickness sections caused
by cracking or abrasion of the inner wall surface, must be
carried out. When this type of welding repair of the inner wall
surface is required, the inner wall surface must first be
subjected to a cleaning operation as a preparatory operation.
In this embodiment, a cleaning operation using a C02 blast device,
which acts as a preparatory operation for a welding repair
operation, is described as an example of an operation that uses
the scaffold apparatus for operations.
As follows is a simple description of the construction
of the digester 1, which represents the operation target.
The digester 1 is formed as a sealed vessel, comprising
a main body section 2 with a large diameter cylindrical structure,
and a digester bottom structure 3 with an end plate construction
joined at the bottom end and a digester top structure 4 joined
at the top end, and is fixed in a vertical position with a bottom
section la of the digester bottom structure 3 supported on a
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base 5.
Furthermore, the main body section 2 has a so-called
"bamboo construction" wherein the diameter dimension reduces
in a stepwise manner from the bottom section la of the digester
1 through to a top section lb, and comprises a first main body
section 21 that has the largest diameter and is joined to the
top edge of the digester bottom structure 3, a second main body
section 22, which is of a smaller diameter than the first main
body section 21 and is joined so that the bottom end thereof
is inserted inside the top end of the first main body section
21, and a third main body section 23, which is of a smaller
diameter than the second main body section 22, is joined so that
the bottom end thereof is inserted inside the top end of the
second main body section 22, and which has the aforementioned
digester top structure 4 joined to the top end thereof.
Accordingly, an inner wall surface 1d of the main body section
2 has a stepped structure in which the internal diameter
dimension varies at the joint regions between the first main
body section 21 through the third main body section 23.
Consequently, a height adjustable operations platform 8
described below, which is used during cleaning operations of
the inner wall surface 1d, has a structure that enables vertical
movement from the first main body section 21 through to the third
main body section 23 without being affected in any way by the
steps at the joint sections between the main body sections.
Furthermore in this embodiment, when a cleaning operation
using C02 blasting is conducted on the inner wall surface of
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the digester 1, in order to ensure good ventilation through the
inside of the digester l, manholes that are provided in the
digester 1 for that purpose are used. In other words, the COz
blasting is a technique in which fine particles of dry ice are
5 projected at the target surface as a blast material, and during
the blasting operation, because C02 gas accumulates at the
bottom inside the digester l, in order to generate a downward
ventilation flow inside the digester 1, an exhaust system 32
is attached to a bottom manhole 31 provided in a central position
10 within the digester bottom structure 3, exhaust systems 33, 34
are disposed at a pair of upper and lower manholes provided
toward the top section lb, and an air supply device 37 is provided
at a large diameter manhole 35 provided substantially halfway
up the digester. This ventilation system ensures a good working
15 environment inside the digester l, and guarantees a highly safe
operation.
In addition, a manhole 36 provided near the joint section
between the digester bottom structure 3 and the first main body
section 21 of the digester 1 is used for carrying materials in
and out of the digester 1, and for people to enter or exit from
the digester 1.
B: Configuration of the Scaffold Apparatus for Operations
As shown in FIG. l, the aforementioned scaffold apparatus
for operations comprises a left and right pair of posts 16, which
are put up from the bottom section la of the digester 1 toward
the top section lb, and the bottom ends of which are supported
by a lower fixed operations floor 6 and the top ends of which
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are supported by an upper fixed operations floor 7, and a height
adjustable operations platform 8 which moves up and down along
each of these posts 16.
The aforementioned lower fixed operations floor 6, the
upper fixed operations floor 7, the height adjustable operations
platform 8, and the posts 16 that make up the scaffold apparatus
for operations are all divided structures, and are each carried
into the digester 1 in a disassembled state through the manhole
36, and then assembled inside the digester 1. As follows is
a description of each of the structural elements, in the order
in which they are assembled.
B-1: Lower Fixed Operations Floor 6
The lower fixed operations floor 6 corresponds with the
"lower support base 6" disclosed in the claims, and is the first
structure assembled during erection of the scaffold apparatus
for operations.
In other words, as shown in FIG. 1, the lower fixed
operations floor 6 is secured near the boundary between the
straight region and the curved region of the aforementioned
digester bottom structure 3 of the digester 1 ( see FIG. 4 ) , and
in addition to its original function as an operations platform,
also performs the important function of acting as a support base
for the posts 16 described below.
As shown in FIG. 3, the lower fixed operations floor 6
is constructed by assembling four support girders 43 in a cross
girder arrangement, and then installing and securing a flooring
material 94 in a circular shape, the periphery of which extends
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out to a position close to, and facing the inner wall surface
1d of the digester l, onto the top of these support girders 43.
Furthermore, a left and right pair of support bases 41, 41 for
mounting and supporting the bottom ends of the posts 16 described
below are provided in positions toward the center of the lower
fixed operations floor 6, and positioning stoppers 42 for
restricting the sideways movement of the bottom ends of the posts
16 are provided on these support bases 41 (see FIG. 5).
As described above, the lower fixed operations floor 6
is carried from outside the digester 1, through the manhole 36
and into the digester in a disassembled state, where it is then
assembled, and consequently all of the structural members must
be formed from parts that are of a size capable of passing through
the manhole 36, and must be bolt secured structures that are
capable of being assembled and disassembled.
Accordingly, in an assembly procedure for the lower fixed
operations floor, first, the four support girders 43 are carried
into the digester 1, and assembled in a cross girder arrangement
inside the digester 1 . In other words, as shown in FIG. 4, eight
securing pieces 45 are welded to the inner wall surface ld at
a position directly above the aforementioned digester bottom
structure 3 of the digester I in advance, with a predetermined
spacing in the circumferential direction. Each securing piece
45 is then attached to a connecting member 46 via a bolt 18,
and the end section of a support girder 43 is then secured to
the connecting member 46 via a bolt 19. The reason that the
securing pieces 45 and the support girders 43 are joined together
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via the aforementioned connecting members 46 is to enable ready
compatibility with changes in the structure of the support
girders 43. Furthermore, when the operations have been
completed and the lower fixed operations floor 6 has been
disassembled and removed, these securing pieces 45 remain
attached to the digester 1, and are used in the next operation.
B-2: Posts 16
As shown in FIG. l, FIG. 2, and FIG. 9, the posts 16 are
put up inside the digester 1 so as to extend from the
aforementioned lower fixed operations floor 6 through to the
upper fixed operations floor 7 described below, and in this
embodiment two posts 16 are arranged in parallel with a
predetermined spacing therebetween, and are connected by j oint
members 17, forming an approximately ladder type structure.
The number of posts 16 to be installed is appropriately
selectable upon the needs, and either a single post, or a set
of three or more posts, may be used.
As described above, the posts 16 are carried from outside
the digester 1, through the manhole 36, and are then assembled
inside, and in this embodiment, a plurality of truss structured
post pieces 16a with a rectangular cross-section (see FIG. 9)
and a length that represent a size capable of passing through
the manhole 36 are prepared, and these are then joined together
sequentially in an axial direction to form a column type
structure.
In other words, the post pieces 16a are carried onto the
lower fixed operations floor 6 via the manhole 36. Then, as
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shown in FIG. 3 and FIG. 5, first, two post pieces 16a are put
up on top of the aforementioned support bases 41 of the lower
fixed operations floor 6, positioned in place by the positioning
stoppers 42, and then secured in place with bolts (not shown
in the drawings). Subsequently, a predetermined number of
additional post pieces 16a are stacked on top of, and connected
to, the bottommost post pieces 16a, sequentially increasing the
height of the posts, and the uppermost post pieces 16a that are
joined last are secured to the upper fixed operations floor 7
described below. Furthermore, a rack 15 (see FIG. 9) that
extends in the axial direction is provided on the post pieces
16a, and when a plurality of post pieces 16a are joined together
to form a post 16, these racks 15 also extend continuously from
the bottom end of the post 16 to the top end.
The operation for stacking and joining the post pieces
16a, the assembly of the upper fixed operations floor 7, and
the operation for joining the floor to the top end of the posts
16, are carried out using the height adjustable operations
platform 8 described below. In other words, in the operation
of putting up the posts 16, once the bottommost post pieces 16a
have been attached, the aforementioned height adjustable
operations platform 8 is assembled on the lower fixed operations
floor 6 and attached to these post pieces 16a, and is then raised
and lowered along these post pieces 16a. This height adjustable
operations platform 8 is then moved sequentially upward, while
the post pieces 16a are sequentially stacked and joined together.
Furthermore, in this case, the disassembled parts for the
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aforementioned upper fixed operations floor 7 are loaded onto
the height adjustable operations platform 8, and following
completion of the joining operation of the uppermost post pieces
16a, the upper fixed operations floor 7 is assembled on top of
5 the height adjustable operations platform 8 and then secured
to the top end of the posts 16 (namely, the top end of the
uppermost post pieces 16a). This completes the assembling of
the posts 16, the bottom ends of which are supported by the lower
fixed operations floor 6, and the top ends of which are supported
10 by the upper fixed operations floor 7.
B-3: Upper Fixed Operations Floor 7
The upper fixed operations floor 7 corresponds with the
"upper support base" disclosed in the claims, and as shown in
FIG. 1, is disposed at a position immediately below the digester
15 top structure 4 of the digester l, and in addition to functioning
as an operations floor as per its original function, also
performs the important function of acting as a top end support
base for the posts 16 as described above.
As shown in FIG. 6, the upper fixed operations floor 7
20 is a circular, flat shape, and is positioned inside the side
walls lc of the digester 1 with a predetermined space retained
between the floor and the side walls lc. Furthermore, the upper
fixed operations floor 7 supports the top ends of the
aforementioned pair of posts 16, 16 via a left and right pair
of post securing members 50, 50 that are provided toward the
center of the floor, while movement in the horizontal direction
is regulated by bracing the tips of j acks 51, 51, . . , which are
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provided at four locations around the outer periphery of the
floor, against the inner wall surface ld of the side walls lc.
In the same manner as the lower fixed operations floor
6 described above, this upper fixed operations floor 7 is also
a knockdown structure that is bolted together, and is carried
into the digester 1 through the aforementioned manhole 36, and
then assembled on top of the height adjustable operations
platform 8.
B-4: Height Adjustable Operations Platform 8
The height adjustable operations platform 8 is used as
an operations floor for the cleaning operation conducted on the
inner wall surface ld of the digester 1 as in this embodiment,
but is also used as the operations floor for a wide variety of
other operations such as inspection operations or repair
operations conducted on the inner wall surface ld, and for the
transport and transfer of operating materials or operators
during any of these operations.
A shown in FIG. 7, the height adjustable operations
platform 8 is formed as a circular shaped flat structure by
attaching a flooring material 49 to the top of girder members
47, 48 that are assembled in a cross girder arrangement, with
a predetermined spacing maintained between the periphery of the
platform and the inner wall surface ld of the digester 1. A
left and right pair of post guides 62, 62 are provided in the
central region of this height adjustable operations platform
8, and the aforementioned posts 16, 16 pass through each of these
post guides 62, 62. Pinion gears 40 that are rotated and driven
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by travel drive motors 30 (which correspond with the "elevator
drive means" disclosed in the claims ) via a pair of bevel gears
38, 39 are attached to one side of each of the post guides 62,
62, namely, on the side of the posts 16 to which the racks 15
are attached, as shown in FIG. 7 and FIG. 9, and these pinion
gears 40 engage with, and travel along the racks 15 on the side
of the posts 16, enabling the height adjustable operations
platform 8 to move up and down along the posts 16 under its own
power.
In addition, as shown in FIG. 7 and FIG. 8, guide wheel
units 9 are provided at four locations around the outer periphery
of the height adjustable operations platform 8. These guide
wheel units 9 run along the inner wall surface ld of the digester
1 when the height adjustable operations platform 8 is raised
or lowered, restricting sideways deviation of the height
adjustable operations platform 8 and ensuring stable up and down
movement.
In other words, the guide wheel units 9 are constructed
by attaching a wheel 10 to the tip of a pivoted arm 11, which
is provided on the height adjustable operations platform 8 and
is free to swing in the radial direction of the digester 1, and
then using a damper 12 to energize the arm 11 to apply pressure
continually in the outward direction. According to such a
construction, because the wheels 10 run along the inner wall
surface ld while being pressed against the inner wall surface
with a constant, predetermined pressure, stability during the
raising and lowering of the height adjustable operations
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platform 8 is ensured at all times, and because the wheels 10
are free to deviate along the radial direction of the digester
1, the wheels 10 are able to accommodate steps (namely, the joint
sections between the first through third main body sections 21
to 23 of the main body section 2) in the inner wall surface ld,
and easily ride over such steps, meaning the reliability of the
movement of the height adjustable operations platform 8 is
ensured.
Because the height adjustable operations platform 8 is
carried through the manhole 36 from outside the digester 1, and
is then assembled inside the digester, each structural member
must be a knockdown structure formed from parts that are of a
size capable of passing through the manhole 36, which are then
bolted together.
C: Cleaning Operation using the Scaffold Apparatus for
Operations
As follows is a description of the operating procedure
for conducting a C02 blast cleaning operation on the inner wall
surface ld of the aforementioned digester 1 using the scaffold
apparatus for operations described above.
As described above, in the aforementioned scaffold
apparatus for operations that has been assembled inside a
digester l, the aforementioned height adjustable operations
platform 8 is freely raised and lowered along the posts 16
between the lower fixed operations floor 6 and the upper fixed
operations floor 7, and consequently, as shown in FIG. 1 and
FIG. 2, an operator M is placed on the height adjustable
CA 02482742 2004-10-12
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operations platform 8, hoses 24 extending from a C02 blast
operations unit 20 located outside the digester 1 are passed
through the bottom manhole 31 provided in the digester bottom
structure 3 of the digester 1 and up onto the top of the height
adjustable operations platform 8, the operator M holds a blast
nozzle 54 attached to the tip of the hoses 24, and a blast
material, namely fine particles of dry ice, proj ected from the
blast nozzle 54 is sprayed onto the inner wall surface ld, and
the impact energy of the blast material removes adherents such
as rust from the surface of the inner wall surface 1d, thereby
producing a clean surface. By conducting this cleaning
operation while the height adjustable operations platform 8 is
sequentially raised or lowered by predetermined distance, the
cleaning operation is performed in a uniform manner over the
entire height of the inner wall surface ld.
In this case, because the blast material sublimes after
projection and becomes C02 gas, a post-operation for recovering
the blast material, such as that required when steel spheres
or the like are used as the blast material, is unnecessary,
meaning the operation is very favorable in terms of improving
the operating efficiency of the overall cleaning operation, and
reducing the operating costs. Furthermore, because of the
difference in specific gravity from air, the C02 gas accumulates
at the bottom of the digester 1, and because a downward
ventilation flow exists inside the digester 1, discharge of the
gas outside the digester 1 is performed very efficiently, the
operating environment inside the digester 1 is maintained at
CA 02482742 2004-10-12
a good condition, and the gas causes absolutely no harm to the
health of the operator M. Coarse particulates generated by the
blasting also get carried along the downward flow and are
discharged externally from the digester l, but to avoid
5 inhalation of these coarse particulates, an air line mask 53
is passed into the digester 1 from the aforementioned manhole
35, as shown in FIG. 1, and the operator M wears this mask.
Focusing on the utility of the height adjustable
operations platform 8, because the wheels 10 of each of the guide
10 wheel units 9 brace the height adjustable operations platform
8 against the inner wall surface ld, sideways swinging during
raising or lowering of the platform is largely inhibited,
enabling a more stable, smoother movement, and improving the
safety during movement, and furthermore, during a cleaning
15 operation while the height adjustable operations platform 8 is
stopped, even if, for example, the projection of the blast
material from the blast nozzle 54 causes a reaction force, the
platform is maintained in a stable state with no sideways rolling,
enabling a very uniform cleaning operation to be conducted on
20 the inner wall surface ld, and ensuring good reliability for
the operation.
In addition, because the wheels 10 of the guide wheel units
9 are capable of being displaced freely toward, and away from,
the inner wall surface ld, when the height adjustable operations
25 platform 8 moves over the joint sections between the first main
body section 21 through the third main body section 23 of the
main body section 2, even if there are steps formed at these
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26
joint sections, by utilizing the aforementioned displacement
function, the wheels 10 easily ride over such steps, and steps
in the inner wall surface ld cause absolutely no impediment to
the movement of the height adjustable operations platform 8.
As a result, stable vertical movement of the height adjustable
operations platform 8 is achieved, meaning the general purpose
applicability of the scaffold apparatus for conducting
operations on the inner wall surfaces of tower structures of
a variety of constructions is improved even further.
Furthermore, because the height adjustable operations
platform 8 is equipped with the aforementioned motors 30 and
is capable of being raised and lowered under its own power,
during various operations that use the height adjustable
operations platform 8, adjustments to the height of the height
adjustable operations platform 8 is performed easily and quickly,
for example in accordance with the requirements of an operator,
meaning both the operability and mobility are good. As a result,
the operating efficiency of operations that are conducted using
the height adjustable operations platform 8 is improved
markedly.
Furthermore on the other hand, focusing on the utility
of the entire scaffold apparatus for operations, which
incorporates the height adjustable operations platform 8, then
in the above embodiment, if the aforementioned posts 16 are put
up inside the digester 1 and the height adjustable operations
platform 8 is then attached to the posts 16, then adjustments
of the installation height of the height adjustable operations
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platform 8 within the digester 1 (that is, the height position
at which operations are conducted using the height adjustable
operations platform 8) is performed easily and quickly by moving
the height adjustable operations platform 8 up or down along
the posts 16, and consequently, compared with a conventional
case in which, for example, a level adjustment operation such
as adding to the scaffold framework is required inside the
digester 1 every time the operating height is altered, the
operability of inner wall surface operations improves markedly,
and because level adjustment operations need not be conducted
at great heights, the safety of the operations also improves,
meaning both operating cost reductions and improved safety are
achieved.
Furthermore, in this embodiment, theaforementioned lower
fixed operations floor 6 is attached via the securing pieces
45 provided on the side wall lc of the digester 1 immediately
above the tower bottom structure 3, and the bottom ends of the
aforementioned posts 16 are supported by this lower fixed
operations floor 6, and consequently the entire weight,
including the dead load of the posts 16 and the attached height
adjustable operations platform 8, and the weight of the operator
M and/or operating materials loaded onto this height adjustable
operations platform 8, is supported directly by the side walls
lc at a point immediately above the tower bottom section 3 of
the digester 1, via the lower fixed operations floor 6, and the
application of load onto the tower bottom section 3 is avoided.
As a result, compared with the case in which the entire weight
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of the posts 16 and the like are supported by the tower bottom
section 3 of the digester l, that is, the region that is typically
constructed from an end plate with a curved surface, the weight
of the posts 16 and the like is supported more reliably and in
a more stable manner, and both the reliability of the
installation of the posts 16 and the like, and the reliability
of the various operations conducted using the posts 16 and the
attached height adjustable operations platform 8 are improved.
Moreover, because the tower bottom section 3 of the digester
1 has the end plate structure described above, that section is
more complex and more expensive to produce than the side wall
section lc, and consequently by not needing to use this tower
bottom section 3 as the support site for the posts 16 and the
like, damage to the tower bottom section 3 is effectively avoided,
resulting in an improvement of the durability of the digester
1, or a reduction of the production costs.
D: Other Factors
In the embodiment described above, the digester 1 was
described as one example of the "tower structure" that is the
target of the present invention, but the "tower structure" is
not restricted to structures such as the digester 1 with a blast
furnace type construction, and for example, also includes
comparatively low structures such as oil storage tanks and the
like. Furthermore, the aforementioned"tower structure" isnot
restricted to pressure vessels such as the aforementioned
digester l, it may be used with comparatively low-pressure
structures too.
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29
Furthermore, in the above embodiment, a cleaning
operation conducted on the inner wall surface of the digester
1 was described as an example of an operation using the scaffold
apparatus for operations, but the scaffold apparatus for
operations according to the present invention is not restricted
to this operation, and is also ideally applied to a variety of
otheroperationsincludinginspection operations, modification
operations, and welding operations. Furthermore, each of these
different types of operations is of course conducted
ZO individually, or a plurality of operations is conducted
conjointly, in parallel.
INDUSTRIAL APPLICABILITY
As described above, the present invention comprises
either a single post or a plurality of posts put up inside a
tower structure from a bottom section thereof toward a top
section, and a height adjustable operations platform that is
attached in a manner that enables free up or down movement along
the posts, and consequently, assembling the posts inside the
tower structure and then attaching the height adjustable
operations platform means that when any of a variety of
operations are conducted on the inner wall surfaces of the tower
structure, adjustments of the installation height of the height
adjustable operations platform within the tower structure is
performed easily and quickly by moving the height adjustable
operations platform up or down along the posts, and consequently,
a level adjustment operation such as adding to the scaffold
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framework is not required inside the tower structure every time
the operating height is altered, enabling a marked improvement
in the operability of inner wall surface operations, and in
addition, because level adjustment operations need not be
5 conducted at great heights, the safety of the operations
improves, meaning the invention is also ideal for achieving both
operating cost reductions and improved safety.
