U.S. patent application number 10/509844 was filed with the patent office on 2005-11-10 for scaffolding device for work on inner wall face of tower vessel body, and method of work on inner wall face using the scaffolding device.
Invention is credited to Fujiwara, Reiki, Ito, Masaaki.
Application Number | 20050247008 10/509844 |
Document ID | / |
Family ID | 29727552 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050247008 |
Kind Code |
A1 |
Fujiwara, Reiki ; et
al. |
November 10, 2005 |
Scaffolding device for work on inner wall face of tower vessel
body, and method of work on inner wall face using the scaffolding
device
Abstract
A scaffold apparatus for operations comprises either a single
post or a plurality of posts (16) put up inside a tower structure
(1), from a bottom section thereof toward a top section, and a
height adjustable operations platform (8) that is attached in a
manner that enables free up or down movement along the posts (16),
and during operation, if the posts (16) are assembled inside the
tower structure (1) and the height adjustable operations platform
(8) is then attached to the posts, then subsequent adjustments of
the operating height is performed easily and quickly by moving the
height adjustable operations platform (8) up or down along the
posts (16), and compared with a 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 operations also
improves, meaning both operating cost reductions and improved
safety are achieved.
Inventors: |
Fujiwara, Reiki; (Ehime,
JP) ; Ito, Masaaki; (Ehime, JP) |
Correspondence
Address: |
Jordan & Hamburg
122 East 42nd Street
New York
NY
10168
US
|
Family ID: |
29727552 |
Appl. No.: |
10/509844 |
Filed: |
September 30, 2004 |
PCT Filed: |
June 3, 2003 |
PCT NO: |
PCT/JP03/07046 |
Current U.S.
Class: |
52/651.1 |
Current CPC
Class: |
E04G 1/362 20130101;
E04G 3/24 20130101; E04G 1/20 20130101; E04G 1/36 20130101; E04G
3/246 20130101 |
Class at
Publication: |
052/651.1 |
International
Class: |
E04H 012/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2002 |
JP |
2002-163776 |
Claims
1. (canceled)
2. The scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to claim 7, the tower
structure further comprising a materials transport port, wherein
said posts each comprise a plurality of stacked and connected post
pieces, the post pieces being of dimensions that enable transport
of the post pieces through the materials transport port provided in
said tower structure, from the bottom section of said tower
structure toward the top section.
3. The scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to claim 7 or claim 2,
further comprising a lower support base for being secured
immediately above a bottommost portion of the tower bottom section
and securing pieces for engaging a side wall of said tower
structure immediately above said bottommost portion of the tower
bottom section for said securing of the lower support base.
4. The scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to claim 7, the tower
structure further comprising a materials transport port, wherein
said height adjustable operations platform is a knockdown structure
that is capable of being transported through the materials
transport port provided in said tower structure.
5. (canceled)
6. (canceled)
7. A scaffold apparatus for conducting operations on an inner wall
surface of a tower structure having top and bottom sections,
comprising: one or two posts for being erected inside the tower
structure from the bottom section thereof toward the top section
thereof; a height adjustable operations platform attached in a
manner that enables free up or down movement along said posts, a
predetermined number of a guide units for maintaining stable up and
down movement of said height adjustable operations platform, the
guide units being equipped on an external periphery of said height
adjustable operations platform, and each of the guide units having
a wheel, the wheel being capable of being displaced freely toward
and away from the inner wall surface of said tower structure and of
being held in continuous contact with said inner wall surface by a
predetermined pressure.
8. A method for conducting operations on an inner wall surface of a
tower structure having top and bottom sections, using a scaffold
apparatus having one or two posts erected inside the tower
structure from the bottom section thereof toward the top section
thereof, a height adjustable operations platform attached in a
manner that enables free up or down movement along said posts, a
predetermined number of a guide units for maintaining stable up and
down movement of said height adjustable operations platform, the
guide units being equipped on an external periphery of said height
adjustable operations platform, each of the guide units having a
wheel capable of being displaced freely toward and away from the
inner wall surface of said tower structure and being held in
continuous contact with said inner wall surface by a predetermined
pressure, the method comprising the steps of: loading a person
and/or an operating material onto the height adjustable operations
platform and adjusting an operating height by moving said platform
up and down along said posts, while performing required operations
on the inner wall surface of said-tower structure.
9. The scaffold apparatus for conducting operations on the inner
wall surface of a tower structure according to claim 7, wherein the
four guide wheel units are located at intervals of 90.degree. on
the external periphery of said height adjustable operations
platform.
10. The scaffold apparatus for conducting operations on an inner
wall surface of a tower structure according to claim 7, wherein
said tower structure comprises a circular cross-section and inside
diameter of the tower structure gradually reduces from the bottom
section to the top section thereof.
11. The method according to claim 8, wherein said tower structure
comprises a circular cross-section and inside diameter of the tower
structure gradually reduces from the bottom section to the top
section thereof.
Description
TECHNICAL FIELD
[0001] 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
[0002] 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.
[0003] 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 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.
[0004] However, according to this operations scaffold assembling
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.
[0005] 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
[0006] 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 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.
[0007] 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 within the
tower structure (that is, the height position at which operations
are conducted using the height adjustable operations platform) 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 improved
safety are achieved.
[0008] 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.
[0009] 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 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.
[0010] 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.
[0011] 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
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.
[0012] 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.
[0013] 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.
[0014] 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 of being
transported through a materials transport port provided in the
tower structure.
[0015] 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.
[0016] Furthermore, a fifth aspect of the present invention is the
scaffold apparatus for conducting operations on an inner 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.
[0017] 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.
[0018] Accordingly, in a scaffold apparatus for conducting
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.
[0019] 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:
[0020] (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;
[0021] (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 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
[0022] (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 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 easily ride over
such 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 operations platform 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.
[0023] 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 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.
[0024] 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
[0025] FIG. 1 is a cross-sectional view of a tower structure
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.
[0026] FIG. 2 is an enlarged view of the height adjustable
operations platform section shown in FIG. 1.
[0027] FIG. 3 is a view along the arrow headed line III-III of FIG.
1.
[0028] FIG. 4 is an enlarged perspective view of the section IV
shown in FIG. 3.
[0029] FIG. 5 is an enlarged cross-sectional view along V-V of FIG.
3.
[0030] FIG. 6 is an enlarged view along the arrow headed line VI-VI
of FIG. 1.
[0031] FIG. 7 is an enlarged view along the arrow headed line
VII-VII of FIG. 1.
[0032] FIG. 8 is an enlarged view along the arrow headed line
VIII-VIII of FIG. 7.
[0033] FIG. 9 is an enlarged view of the section IX shown in FIG.
7.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] 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 CO.sub.2 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.
[0035] 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.
[0036] A: Configuration of the Digester 1
[0037] 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 CO.sub.2 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.
[0038] As follows is a simple description of the construction of
the digester 1, which represents the operation target.
[0039] 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 1a of the digester bottom structure 3 supported on a base
5.
[0040] 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 1a of the digester 1 through to a
top section 1b, 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.
[0041] Furthermore in this embodiment, when a cleaning operation
using CO.sub.2 blasting is conducted on the inner wall surface of
the digester 1, in order to ensure good ventilation through the
inside of the digester 1, manholes that are provided in the
digester 1 for that purpose are used. In other words, the CO.sub.2
blasting is a technique in which fine particles of dry ice are
projected at the target surface as a blast material, and during the
blasting operation, because CO.sub.2 gas accumulates at the bottom
inside the digester 1, 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 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
1b, 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 environment inside the
digester 1, and guarantees a highly safe operation.
[0042] 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.
[0043] B: Configuration of the Scaffold Apparatus for
Operations
[0044] As shown in FIG. 1, the aforementioned scaffold apparatus
for operations comprises a left and right pair of posts 16, which
are put up from the bottom section 1a of the digester 1 toward the
top section 1b, and the bottom ends of which are supported by a
lower fixed operations floor 6 and the top ends of which 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.
[0045] 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.
[0046] B-1: Lower Fixed Operations Floor 6
[0047] 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.
[0048] 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.
[0049] 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
44 in a circular shape, the periphery of which extends out to a
position close to, and facing the inner wall surface 1d of the
digester 1, 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).
[0050] 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.
[0051] 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 1d at a
position directly above the aforementioned digester bottom
structure 3 of the digester 1 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 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.
[0052] B-2: Posts 16
[0053] As shown in FIG. 1, 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 joint 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.
[0054] 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.
[0055] In other words, the post pieces 16a are carried onto the
lower fixed operations floor 6 via the manhole 36. Then, as 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.
[0056] 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 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 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 by the upper fixed operations floor 7.
[0057] B-3: Upper Fixed Operations Floor 7
[0058] 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 top
structure 4 of the digester 1, 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.
[0059] As shown in FIG. 6, the upper fixed operations floor 7 is a
circular, flat shape, and is positioned inside the side walls 1c of
the digester 1 with a predetermined space retained between the
floor and the side walls 1c. 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 jacks 51, 51, . . . , which are provided at four locations
around the outer periphery of the floor, against the inner wall
surface 1d of the side walls 1c.
[0060] 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.
[0061] B-4: Height Adjustable Operations Platform 8
[0062] The height adjustable operations platform 8 is used as an
operations floor for the cleaning operation conducted on the inner
wall surface 1d 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 1d, and for the transport and
transfer of operating materials or operators during any of these
operations.
[0063] 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 1d 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 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.
[0064] 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 1d 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.
[0065] 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 1d while being
pressed against the inner wall surface with a constant,
predetermined pressure, stability during the raising and lowering
of the height adjustable operations 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 1d, and easily ride over such steps,
meaning the reliability of the movement of the height adjustable
operations platform 8 is ensured.
[0066] 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.
[0067] C: Cleaning Operation Using the Scaffold Apparatus for
Operations
[0068] As follows is a description of the operating procedure for
conducting a CO.sub.2 blast cleaning operation on the inner wall
surface 1d of the aforementioned digester 1 using the scaffold
apparatus for operations described above.
[0069] As described above, in the aforementioned scaffold apparatus
for operations that has been assembled inside a digester 1, 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 operations platform 8, hoses 24
extending from a CO.sub.2 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, projected from
the blast nozzle 54 is sprayed onto the inner wall surface 1d, 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 1d.
[0070] In this case, because the blast material sublimes after
projection and becomes CO.sub.2 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 CO.sub.2 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 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 1, but to avoid 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.
[0071] Focusing on the utility of the height adjustable operations
platform 8, because the wheels 10 of each of the guide wheel units
9 brace the height adjustable operations platform 8 against the
inner wall surface 1d, 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 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 the inner wall surface 1d, and
ensuring good reliability for the operation.
[0072] 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 1d, when the height adjustable operations
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 joint
sections, by utilizing the aforementioned displacement function,
the wheels 10 easily ride over such steps, and steps in the inner
wall surface 1d 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.
[0073] 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.
[0074] 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 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.
[0075] Furthermore, in this embodiment, the aforementioned lower
fixed operations floor 6 is attached via the securing pieces 45
provided on the side wall 1c 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 1c 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 of the posts 16 and the
like are supported by the tower bottom section 3 of the digester 1,
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 1c, 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.
[0076] D: Other Factors
[0077] In the embodiment described above, the digester 1 was
described as one example of the "tower structures 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" is not
restricted to pressure vessels such as the aforementioned digester
1, it may be used with comparatively low-pressure structures
too.
[0078] 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 other operations including
inspection operations, modification operations, and welding
operations. Furthermore, each of these different types of
operations is of course conducted individually, or a plurality of
operations is conducted conjointly, in parallel.
INDUSTRIAL APPLICABILITY
[0079] 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 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 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.
* * * * *