U.S. patent application number 11/378239 was filed with the patent office on 2006-08-10 for fireproof structure and installation method for protecting water pipes.
Invention is credited to Keita Inoue, Yuji Nakagawa, Kentaro Saeki, Yasunori Terabe.
Application Number | 20060174559 11/378239 |
Document ID | / |
Family ID | 19157410 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060174559 |
Kind Code |
A1 |
Terabe; Yasunori ; et
al. |
August 10, 2006 |
Fireproof structure and installation method for protecting water
pipes
Abstract
A fireproof structure protects water pipes with stable
durability even in a high temperature gas environment. Even in a
case where it falls off, it does not leave the water pipes suddenly
exposed. The fireproof structure for protecting water pipes 25B
installed on water pipe walls of a combustion gas side is
configured by a double-layered structure made up of an outer layer
water pipe protective structure facing towards the combustion gas
side, which is fireproof tile 13, and an inner layer water pipe
protective structure provided between the outer layer water pipe
protective structure and the water pipes, which is fireproof
castable 12. The thickness ratio between the castable 12 and the
tiles 13 lies within the range of about 2:1 to 3:1, and the ratio
between the thickness of the fireproof castable and the radius of
the water pipe is set to 1+.alpha.:1, wherein the value of .alpha.
ranges from approximately 0.1 to 0.3. The water pipes are equipped
with hanging hooks 15a for tiles 13.
Inventors: |
Terabe; Yasunori;
(Yokohama-shi, JP) ; Inoue; Keita; (Yokohama-shi,
JP) ; Nakagawa; Yuji; (Yokohama-shi, JP) ;
Saeki; Kentaro; (Yokohama-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
19157410 |
Appl. No.: |
11/378239 |
Filed: |
March 20, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10289406 |
Nov 7, 2002 |
|
|
|
11378239 |
Mar 20, 2006 |
|
|
|
Current U.S.
Class: |
52/198 |
Current CPC
Class: |
F22B 37/108
20130101 |
Class at
Publication: |
052/198 |
International
Class: |
E04B 7/00 20060101
E04B007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 8, 2001 |
JP |
2001-343789 |
Claims
1. A fireproof wall structure of combustion equipment including: a
refractory tube wall lining; and a tube wall which comprises water
pipes and water pipe connecting fins joining adjacent ones of the
water pipes of the tube wall, said tube wall lining being formed on
a combustion gas side of the said tube wall; wherein said lining
comprises two kinds of layers, an inner layer and an outer layer;
wherein said inner layer is formed on a combustion gas side surface
of said tube wall and said outer layer is attached on said inner
layer; wherein said inner layer and said outer layer are formed of
different material; wherein said inner layer is formed of material
selected from the group consisting of nickel-chrome and nickel base
alloy and has been deposited on the combustion gas side of said
tube wall by cladding or thermal spraying; and wherein said outer
layer is formed of fireproof castable or fireproof tiles attached
on said inner layer.
2. A stoker type incinerator having said fireproof wall structure
of claim 1 thereon, said stoker type incinerator having a furnace
outlet temperature of approximately 900 to 1200.degree. C.
3. A stoker type incinerator having said fireproof wall structure
of claim 1 thereon, said stoker type incinerator having a furnace
outlet temperature of approximately 900 to 1200.degree. C. at an
uppermost part of said fireproof wall structure of the
incinerator.
4. A stoker type incinerator having said fireproof wall structure
of claim 1 thereon and having a secondary air inlet provided at a
lower part of said fireproof wall structure, wherein the outer
layer formed around and below said secondary air inlet is formed of
fireproof castable.
5. A stoker type incinerator having said fireproof wall structure
of claim 1 thereon, wherein said outer layer is formed by fireproof
tiles for areas of said fireproof wall structure subject to high
heat loads.
6. A stoker type incinerator having said fireproof wall structure
of claim 1 thereon, wherein said outer layer is formed by fireproof
tiles and said fireproof wall structure further comprises hanging
members integrated with said tube wall of said fireproof wall
structure.
Description
[0001] This is a divisional application of U.S. patent application
Ser. No. 10/289,406, filed Nov. 7, 2002.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a fireproof structure and
installation method for water pipes used in heat exchangers in
incinerators, boilers and the like which protects them in high
temperature gas environments.
[0004] 2. Description of the Related Art
[0005] Water pipes are installed inside of trash incinerators,
boilers and the like to cool the high temperature gas environment
or perform heat exchange. Those water pipes have been protected
from not only the high temperature gas environment, but the
abrasion from flying ash and corrosion, by the installation of
fireproof tiles or fireproof castable structures around the inside
of the furnace walls.
[0006] Such conventional fireproof structures, as shown in FIG. 9,
have studs 14 protruding from water pipes 10 on the combustion
chamber side of the water pipe wall, in other words, the side in
contact with the high temperature gases. Also employed are sleeves
19 embedded inside fireproof castable 12; the foregoing studs 14
inserted into the sleeves 19 are held by the foregoing fireproof
castable 12.
[0007] The foregoing fireproof castable 12 contains SiC, which
exhibits high thermal conductivity and is chemically stable. The
foregoing studs 14 are made of stainless steel materials, and the
sleeves 19 are made of ceramic material. The sleeves 19 protect the
foregoing studs 14 from corrosion by the waste gases and further
serve to prevent the fireproof castable from cracking and chipping
off due to studs 14.
[0008] This structural method for fireproof structures using
fireproof castable materials was disclosed in Japan Patent
Publication Hei 8-21688 (1996).
[0009] Also, Japan Patent Publication 2000-167816 proposed a
fireproof tile using SiC and other ceramic raw materials. FIGS. 10
and 11 show a fireproof structure using the fireproof tiles
disclosed in that invention.
[0010] In that structure, fins 11 that join adjacent water pipes 10
include projecting hanging members 15d. The hanging members 15d
affix fireproof tiles 13 with mortar 20 on the high temperature gas
side of water pipes 10 through the projecting hanging member.
[0011] As is shown in the side view, FIG. 11, the hanging members
15d comprise an L-shaped support hook. The L-shaped hooks provide
support by allowing insertion of the fireproof tiles from above,
which tiles are equipped with attachment holes.
[0012] However, the problem with the above described fireproof
castable is that because it is of irregular dimensions, being
coated or sprayed directly onto the walls of the water pipes, the
durability of the resulting fireproof structure becomes unstable;
after a few years, it tends to massively flake away or collapse.
With regard to the fireproof structure comprised of the externally
formed and manufactured fireproof tiles described above, even
though the tiles themselves have excellent durability, should any
of them fall off, the water pipe can be directly exposed, and be
damaged by the high temperatures and corrosive gasses.
[0013] In particular, when used in the stoker-type incinerators
where the outlet temperatures can reach to an extremely high
1000.degree. C., the difference between the thermal expansion of
the support members for the fireproof structures using the
foregoing fireproof castables or fireproof tiles, and that of the
fireproof structure, causes cracks to form where combustion gases
can invade and subsequently corrode the foregoing support members.
As a result, the foregoing fireproof structures are prone to
separation and falling away, thereby allowing holes to form in the
water piping.
SUMMARY OF THE INVENTION
[0014] The present invention addresses the problems associated with
the prior art. Its objective is to provide a fireproof structure
for protecting water pipes and an installation method employing a
fire proof structure which, even in the case where it falls off,
does not leave the water pipes suddenly exposed, and even if the
fireproof structure comes into contact with high temperature
combustion gases, the fireproof structure assures protection for
the water pipes and support members.
[0015] At this point, the present invention, in order to resolve
these problems, provides a fireproof structure for protecting water
pipes installed on the water pipe walls of the combustion gas side
used for trash incinerators, boilers or other combustion equipment.
It is characterized by the following. The fireproof structure is
configured by a double-layered structure consisting of an outer
layer water pipe protective structure facing towards the combustion
gas side, and an inner layer water pipe protective structure
provided between the outer layer water pipe protective structure
and the water pipes. The outer layer water pipe protective
structure and the inner layer water pipe protective structure are
formed from different materials. The outer layer water pipe
protective structure is comprised of a fireproof castable or
fireproof tile, and the inner layer water pipe protective structure
is selected from a cladding deposit, thermal spraying deposit, or
fireproof castable.
[0016] The present invention, characterized by providing a
double-layered fireproof structure to cover water pipes, each
deriving fireproof properties from different substances, provides
assured protection from corrosion and abrasion in the high
temperature gas environment. The foregoing fireproof tile exhibits
high durability due to its high specific density and uniform
density distribution. The foregoing fireproof castable is easily
installed, and should it fall off or crumble, the water pipes are
not suddenly exposed. Further, the aforementioned cladding deposit
has a thermal expansion rate that is similar to that of the water
pipes to thereby provide assured protection without cracking.
[0017] These fireproof structures can be used in the following
combinations, for example, (in the order of outer layer water pipe
protective structure--inner layer water pipe protective structure)
fireproof tile--fireproof castable, fireproof tile--cladding
deposit, fireproof tile--thermal spraying deposit, fireproof
castable--cladding deposit, and fireproof castable--thermal
spraying deposit.
[0018] Thus, the problems with the prior art cited above may be
resolved by using these combinations of materials, providing
assured protection of the water pipes.
[0019] The use of silicon carbide or bonded silicon nitride and
silicon carbide is recommended in the foregoing fireproof tile and
fireproof castable to improve their heat exchange efficiency. High
corrosion resistant nickel-chrome, Ni based alloy, or the like are
recommended for the foregoing cladding or thermal spraying
deposits.
[0020] Another aspect of the invention is characterized by the
fireproof structure installed on the water pipe walls in stoker
type incinerators having a furnace outlet temperature of
approximately 900 to 1200.degree. C.
[0021] Yet another aspect of the invention is characterized by the
fireproof structure used for the water pipes of stoker type
incinerators having a furnace outlet temperature of approximately
900 to 1200.degree. C. at the uppermost fireproof structure in the
furnace.
[0022] A further aspect of the invention is characterized in that
the furnace outlet is approximately 900 to 1200.degree. C. at the
upper most fireproof structure in the furnace.
[0023] The outlet temperature in furnaces means generally the
temperature in the uppermost part where the fireproofing is applied
in the furnace.
[0024] These inventions are applicable especially for furnaces in
the widely spread stoker type incinerators, which operate at high
temperatures. If the inside of the furnace is high temperature, the
thermal expansion is huge. In such case, there is a big difference
in the thermal expansions between the supports provided to the
water pipes and the fireproof structure. This causes cracking and
damage to the conventional, single-layered fireproof structures,
and allows holes to form in the water pipes. Accordingly, the above
described double-layered fireproof structure provides assured
protection of the water pipes even in high temperature gas
environments.
[0025] Further, another aspect of the invention is characterized by
the fireproof structure for protecting water pipes which is
provided with a fireproof castable for areas where the water pipes
assume a complex shape, and a fireproof tile for areas where the
water pipes assume an approximately linear shape.
[0026] This arrangement allows the easy installation of
fireproofing in areas where the water pipes are arrayed in a
complex shape by using an amorphous fireproof castable rather than
fireproof tiles when dealing with areas where there are bends and
projections in the water pipes, such as around manholes (openings
for worker egress), air ducts, and openings for the insertion of
measuring equipment.
[0027] Further still, another aspect of the invention relates to a
fireproof structure for protecting water pipes which is
characterized as follows. The fireproof structure is installed in a
stoker type incinerator which has a secondary air duct at the lower
part of the inner wall of the furnace. The outer layer water pipe
protective structure for the water pipes, installed in the area
around and the lower area of the secondary air ducts, is a
fireproof castable, and the inner layer water pipe protective
structure is a cladding deposit or a thermal spraying deposit.
[0028] The foregoing stoker type incinerators use primary air which
is supplied from the bottom of the furnace and secondary air which
is supplied from the lower area of the inner furnace walls. The
secondary air is used to control combustion. Further, it is often
the case that a complex water pipe structure exists at the
secondary air ducts, around and below them. Accordingly, it would
be cost effective and easy to install a fireproof castable,
cladding deposit, or thermal spraying deposit having uneven
surfaces in such areas.
[0029] Further, in the vicinity of the foregoing secondary air
ducts, where harsh air blasts are apt to cause considerable damage,
it is possible to assure the protection of the water pipes by
employing an inner layer water pipe protective structure comprised
of a cladding deposit or thermal spraying deposit.
[0030] Also, another aspect of the invention is characterized by
that the fireproof structure, in at least the areas where the water
pipe walls are subject to high heat loads, is configured by the
outer layer water pipe protective structure being formed by
fireproof tiles and the inner layer water pipe protective structure
being formed by a cladding deposit or as a thermal spraying
deposit.
[0031] With this arrangement, placing highly heat resistant
fireproof tiles in areas subjected to high heat loads makes it
possible to prevent damage or degradation due to the high heat
loads, reduces the frequency of maintenance, and minimizes
operating costs.
[0032] Yet another aspect of this invention is characterized by the
outer layer water pipe protective structure being formed by
fireproof tiles, and hanging members being provided on the water
pipes of the water pipe walls to hang the fireproof tiles on the
walls.
[0033] Thus, by integrating the foregoing hanging members, which
support the aforementioned fireproof tiles, on the water pipes,
being the flow path for the cooling water, there is no concern for
heat damage to the hanging members because they are cooled.
Further, the foregoing hanging members, being L-shaped or similarly
shaped hanging members, prevent the tiles from falling off.
[0034] Yet another aspect of this invention is characterized by the
outer layer water pipe protective structure being formed by
fireproof tiles, and the inner layer water pipe protective
structure being formed by fireproof castable, with the thickness
ratio between the castable and the tiles lying within the range of
about 2:1 to 3:1.
[0035] The combination of the foregoing fireproof tiles and the
forgoing fireproof castable of this invention serves to improve
durability and to protect the water pipes with the fireproof
castable, thereby preventing their exposure in the event that one
of the foregoing fireproof tiles falls off.
[0036] In this case, should the thickness ratio of the foregoing
fireproof castable be less than the 2:1 specified above, should any
fireproof tiles fall off, the thinnest areas of the fireproof
castable covering the water pipes would not be thick enough to
prevent the water pipe from being suddenly exposed. On the other
hand, if the wall thickness ratio of the foregoing fireproof
castable exceeds 3:1, then the cooling effects by the water pipes
on the fireproof tiles would be diminished, which would in turn
decrease the durability of the hanging members of the fireproof
tiles.
[0037] Accordingly, maintaining the foregoing thickness ratio at
between about 2:1 and 3:1 assures the protection of the water pipes
and additionally improves the durability of the hanging
members.
[0038] Further, another aspect of this invention is characterized
by the outer layer water pipe protective structure being formed by
fireproof tiles, the inner layer water pipe protective structure
being formed by fireproof castable, and the ratio between the
thickness of the fireproof castable and the radius of the water
pipe being set to 1+.alpha.:1, with the value of .alpha. ranging
from approximately 0.1 to 0.3.
[0039] The ratio in this invention of 1+.alpha.:1 (where
.alpha.=approximately 0.1 to 0.3), similar to the case with the
foregoing aspect of the invention mentioned above, assures that in
the case that a fireproof tile falls off, the water pipe will not
become immediately exposed, and that relationship also assures that
a high cooling effect will be imparted to the foregoing fireproof
tiles' hanging members.
[0040] What is meant by the thickness of the foregoing fireproof
castable is the thickness from the fins connecting the foregoing
water pipes to the surface of the fireproof castable.
[0041] Further, since the fireproof castable is held between the
foregoing fireproof tiles and the water pipes, by means of
appropriately selecting the thickness of said fireproof castable as
described above, it is possible to use flat fireproof tiles, which
facilitates installation and manufacturing and keeps installation
costs low.
[0042] Further, other aspects of this invention relate to
installation methods for the foregoing fireproof structures of this
invention. The installation method for a fireproof structure for
protecting water pipes installed on the water pipe walls of the
combustion gas side used for incinerators, boilers or other
combustion equipment is characterized by comprising a structural
installation process for an inner protective layer for the water
pipes to install one material from a cladding deposit, thermal
spraying deposit and fireproof castable over the water pipe walls
facing the combustion gas side, and a structural installation
process for an outer protective layer for the water pipes to be
installed upon the surface above the inner protective layer for
water pipes, a fireproof castable or fireproof tiles, wherein the
inner protective layer and the outer protective layer for water
pipes consist of differing materials.
[0043] Also, another aspect of this invention is characterized by
an installation method for a fireproof structure for protecting
water pipes installed on the water pipe walls of the combustion gas
side used for incinerators, boilers or other combustion equipment,
comprising a fireproof castable installation process to install a
fireproof castable over the water pipe walls facing the combustion
gas side and a fireproof tile installation process to apply an
adhesive, such as mortar or the like, on the surface of the
fireproof castable, and then fix fireproof tiles thereon.
[0044] Further, another aspect of this invention is characterized
by an installation method for a fireproof structure mentioned
above, further comprising a water drain process to drain water from
the pre-formed holes in connecting fins joining the adjacent water
pipes after the fireproof tile installation process and a hole plug
process to plug the remaining holes after draining the water.
[0045] The installation methods mentioned above are for installing
the fireproof structure for protecting water pipes mentioned
previously. Since these inventions involve first directly
installing an amorphous structure over the water pipes, it is
possible to perform such installations over the irregular surface
formed by the water pipes. Further, should the water pipes have
complex shapes including bends or projections, it is still possible
to install a fireproof castable for the outer protective layer for
the water pipes and avoid the need and associated costs of
manufacturing several different shapes/types of fireproof
tiles.
[0046] The inventions described above involve installation methods
for an outer protective layer for water pipes of fireproof tiles,
and an inner protective layer of fireproof castable. The water
drainage from the fireproof castable held under the fireproof tiles
or cladding deposit or thermal spraying deposit is drained through
the holes in the aforementioned fins, and after the drainage is
performed, welding or other methods is used to plug the holes.
Thus, having holes preformed in the foregoing fins facilitates the
water drainage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] FIG. 1 is a cross sectional view of a first embodiment of
this invention showing a fireproof protective structure for water
pipes.
[0048] FIG. 2 is a cross sectional view of a second embodiment
showing the fireproof protective structure for water pipes.
[0049] FIG. 3 is a cross sectional view of a third embodiment
showing the fireproof protective structure for water pipes.
[0050] FIG. 4 is a cross sectional view at line A-A shown in FIG.
2.
[0051] FIG. 5 is a cross sectional view of a fourth embodiment
showing the fireproof protective structure for water pipes.
[0052] FIG. 6 is a cross sectional view of a fifth embodiment
showing the fireproof protective structure for water pipes.
[0053] FIG. 7 is a cross sectional view of a sixth embodiment
showing the fireproof protective structure for water pipes.
[0054] FIG. 8 is a rough overall sketch of the fireproof structure
installed in a stoker type incinerator.
[0055] FIG. 9 is a cross sectional view of a conventional fireproof
structure for protecting water pipes, which uses fireproof
castable.
[0056] FIG. 10 is a cross sectional view of a conventional
fireproof structure for protecting water pipes.
[0057] FIG. 11 is a cross sectional view of line B-B shown in FIG.
10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0058] In this section we shall explain several preferred
embodiments of this invention with reference to the appended
drawings. Whenever the size, materials, shapes, relative positions
and other aspects of the parts described in the embodiments are not
clearly defined, the scope of the invention is not limited only to
the parts shown, which are meant merely for the purpose of
illustration.
[0059] FIG. 1 is a cross sectional view of a first embodiment
showing the fireproof protective structure for water pipes; FIG. 2
is a cross sectional view of a second embodiment showing the
fireproof protective structure for water pipes; FIG. 3 and FIGS. 5
through 7 show the third through sixth embodiments of the present
invention in cross sectional views.
[0060] In these embodiments, a stoker type of incinerator is taken
as an example for the installation of the fireproof structure.
Further, the outlet temperature of this stoker type incinerator is
in the range of, approximately, 900 to 1200.degree. C., and the
furnace wall temperature will rise to about 800.degree. C.
[0061] In FIGS. 1-7, 10 represents water pipes, 16 a coolant flow
path, and 11 the flat surfaced fins which connect and reinforce the
water pipes with each other in the horizontal or perpendicular
directions. The water pipes 10 and fins 11 form a water pipe wall
structure 26.
[0062] 12 represents fireproof castable, which is primarily
comprised of SiC; similarly, 13 represents fireproof tiles,
primarily comprised of SiC. The foregoing fireproof castable 12 may
be installed, for example, by spraying the castable over the
outside circumferential surface of the water pipes and allowing it
to harden, or by erecting a framed mold opposite to the water pipes
10, casting the castable to fill the space, and subsequently
allowing it to harden before removing the mold. By contrast, the
aforementioned fireproof tiles 13, primarily composed of SiC, are
molded in a factory, pressed, sintered or otherwise manufactured in
advance, and then the manufactured tiles 13 are installed with
mortar or other adhesive material as an attachment component on the
wall of the water pipes. In addition to the SiC contained in the
forgoing fireproof tiles and castable, there is no limit to the
other ingredients, such as SK, and Si.sub.3N.sub.4, to improve heat
conductivity, or ingredients that improve durability or corrosion
resistance, which may be included as desired.
[0063] The first embodiment of the fireproof structure 25A
according to this invention, as shown in FIG. 1, employs a
plurality of studs 14 in sets of two and three, projecting
alternately from adjacent water pipes 10 at approximate 45 degree
angles on the side where fireproof castable 12 is installed. This
structural arrangement makes it very difficult for the fireproof
castable 12 to fall off. It is preferable that the studs 14 be made
from the same type of material as the water pipes to prevent studs
14 from causing damage due to having a different thermal expansion
rate than water pipes 10. It is also desirable, as shown in FIG. 9,
that the foregoing studs 14 be inserted into sleeves.
[0064] Further, stainless steel hanging hooks 15a have been welded
to the foregoing fins 11 to hold the tiles in place. Also, as is
shown for fireproof tiles 13 in FIG. 11, the tiles 13 may be held
in place by using grooved tiles that engage the hanging hooks
15a.
[0065] Holes 11a have been pre-formed in the foregoing fins 11.
These holes 11a make it possible to drain the water after the
casting of fireproof castable 12 and attaching fireproof tiles 13
by means of the tile-hanging hooks 15a to hold the tile in place.
Then, after draining the water through holes 11a, the holes 11a may
be plugged by welding, etc., to eliminate the possibility of
residual water between the water pipes and the tile, to thereby
easily complete the installation of fireproof structure 25A. At
this time, it would also be possible to drill holes in the
fireproof tile side, and after draining the water from the
foregoing fireproof castable 12, such holes also could be plugged
with mortar, etc.
[0066] In this first embodiment, when the radius R for the water
pipes 10 arrayed in this stoker type incinerator is approximately
38 mm, the thickness Ha of the fireproof structure comprised of the
foregoing fireproof castable 12 and fireproof tiles 13 is about 70
mm, with the thickness Hk of the foregoing fireproof castable 12
being approximately 50 mm and the thickness Ht of the foregoing
tiles 13 being about 20 mm.
[0067] Thus, the ratio of the thickness Hk of the foregoing
fireproof castable 12 to the thickness Ht of the foregoing
fireproof tiles 13, Hk:Ht=2:1 to 3:1, or the ratio of the thickness
Hk of the foregoing fireproof castable 12 to the radius R of water
pipes 10 is approximately Hk:R=1+.alpha.:1. With this structure, in
the unlikely event of any of the foregoing fireproof tiles 13
falling off, the water pipes would not become suddenly exposed, and
it is further possible to prevent damage to the hanging hooks 15a
due to the heightened cooling effect on the aforementioned tile
hanging hooks 15a.
[0068] FIG. 2 shows a second embodiment of a fireproof structure
25B, wherein water pipes 10 are arrayed as in the first embodiment
and have L-shaped tile hanging hooks 15a made of a similar
material. The foregoing fins 11 have a Y-shaped anchor 17. Since
the other elements of the structure are similar to those of the
first embodiment, further explanation of them will be omitted.
[0069] FIG. 4 is a cross sectional view of the second embodiment
taken along line A-A of FIG. 2. 10 is the water pipes forming the
coolant path 16, which are covered around their outside
circumferences on the side facing the inside of the furnace by
fireproof castable 12. Fireproof tiles 13 are installed atop that
castable, and are held in place by hanging them onto L-shaped
hanging hooks 15a and affixing with mortar 20.
[0070] FIG. 3 shows a third embodiment of fireproof structure 25C.
The structure of this third embodiment is similar to those of the
first and second embodiments, but the number of parts have been
reduced by using the same L-shaped hooks for the tile hanging hooks
15a and for the castable support hooks 15b.
[0071] Since the fireproof structures in these embodiments are
two-layered structures comprised of the foregoing fireproof
castable 12 and fireproof tiles 13, should any of the fireproof
tiles 13 facing the high temperature gas environment suddenly fall
off, the foregoing fireproof castable 12 would serve to protect the
water pipes in that area to assuredly prevent the exposure of the
water pipes.
[0072] Further, since the foregoing tile hanging hooks 15a protrude
from water pipes 10, the cooling effect provided by that structure
prevents diminished durability of the hanging hooks 15a, even in
extremely high temperature stoker type incinerators.
[0073] The fireproof tiles 13 used in these embodiments may be
flat-shaped tiles, which facilitates their manufacture and
installation, and makes them less expensive to produce. Further,
one is not confined to using the L-shaped hooks or Y-shaped anchors
to retain the fireproof tiles and fireproof castable, and any type
of retaining structure or combination thereof may be used to
support the fireproof structure.
[0074] FIG. 5 shows a fourth embodiment, where thermal spraying
deposit has been used around the outside circumference of water
pipes 10 in making a fireproof structure 25D. In this embodiment,
water pipes 10 have been coated with thermal spraying deposit 18b,
and then fireproof tiles 13 have been installed around the
circumferences of that structure. The preferred thickness for
thermal spraying deposit 18b would range from about 0.1 to 1.0 mm,
and the material should be an alloy such as 50 Ni-50 Cr.
[0075] It would also be possible to use a cladding deposit other
than the foregoing thermal spraying deposit 18b. In that case, the
thickness of the structure should range from about 1 to 10 mm, and
the material used for the build up should be a nickel based alloy
such as Inconell.
[0076] In the fifth embodiment shown in FIG. 6, a nickel based
alloy is clad around the outer circumference of water pipes 10, and
then fireproof castable 12 is installed thereupon. In this
fireproof structure 25E, the inner protective layer for water pipes
is cladding deposit 18a, while the outer protective layer for water
pipes is fireproof castable 12.
[0077] Also, FIG. 7 shows the sixth embodiment, where an Ni--Cr
alloy has been applied by thermal spraying around the outer
circumference of water pipes 10. The fireproof structure 25F
accordingly has an inner protective layer for water pipes of the
thermal spraying deposit 18b, and an outer protective layer for
water pipes of the fireproof castable 12.
[0078] The fireproof structures of the fifth and sixth embodiments
require no mortar or other adhesive application for the
installation of the fireproof castable or for the structure of the
cladding deposit 18a or thermal spraying deposit 18b, and
accordingly have fewer layers compared to the conventional use of
fireproof tiles, yet still permit the use of studs 14 as support
members. The structure is not prone to damage to the support
members or the flaking off of layers. The use of sleeves 19 in such
applications is recommended.
[0079] Thus, using a cladding deposit 18a or thermal spraying
deposit 18b to make molten contact around the outer circumference
of water pipes 10 provides strong protection for the water pipes,
and even if a fireproof tile 13 should fall off of such a
structure, the underlying water pipes would not become exposed.
[0080] However, due to the high cost of the cladding deposits 18a
or thermal spraying deposit 18b, the use of these methods may be
economically confined to only the high temperature areas inside the
furnace. Further, in these embodiments, although the cladding or
thermal spraying deposits were used to form the inner protective
layer for water pipes, it would also be possible to structure the
inner protective layer from fireproof castable materials.
[0081] Next, the fireproof structure will be described for the case
where it is installed in a stoker type incinerator as shown in FIG.
8.
[0082] This stoker type incinerator 30 is comprised of input hopper
32 where trash is added, grate 31 where the trash is burned using
primary air supplied from the bottom of the incinerator, primary
combustion chamber 34 located above grate 31, and secondary
combustion chamber 33, located there above, where a supply of
secondary air is used to burn the unburned residuals.
[0083] The foregoing grate 31 is equipped with a primary air inlet
(not shown) which supplies oxygen-enriched air, and secondary air
inlet 35 is located below the foregoing secondary combustion
chamber 33.
[0084] At the bottom of the foregoing secondary combustion chamber
33 is a manhole 36 for the access of workers to perform
maintenance, etc. on the burner (not shown), and there are, in
addition, several other openings for the insertion of monitoring
equipment and the like.
[0085] The water pipes installed in the incinerator 30 run roughly
linearly in the vertical direction around the foregoing secondary
combustion chamber 30, while in the primary combustion chamber 34,
they are bent from the vertical toward the grate.
[0086] Accordingly, with regard to the fireproof structure
installed in incinerator 30, in the areas around and below the
foregoing secondary air inlet 35, and around manhole 36, where the
water pipes have bends, it is best to install an inner protective
layer for water pipes described in the fifth and sixth embodiments,
which uses a cladding deposit 18a or thermal spraying deposit 18b
that is covered by an outer protective layer for water pipes
comprised of fireproof castable 12. On the other hand, in the area
above the foregoing secondary air inlet 35 and where the water
pipes run approximately linearly it would be best to use the
structures of the first, second, third and fourth embodiments with
fireproof tiles 13 as the outer protective layer for the water
pipes.
[0087] Here, in the areas of high heat loads or around the air
inlets where there is a high potential for damage, the water pipes
may be protected by partially installing an inner layer water pipe
protective structure of a cladding deposit 18a or thermal spraying
deposit 18b. However, in areas where there is little potential for
damage, the water pipes may be protected with a single layer of
fireproof castable 12 or fireproof tiles 13 to reduce the
installation costs.
[0088] The foregoing is merely one example of installing a
fireproof structure in an incinerator. It is possible to combine
the various types of fireproof structures to realize a low cost,
durable, high heat resistant fireproof structure.
[0089] As described above, according to this invention, the
fireproof structure covers the water pipes with two layers of
differing materials having differing characteristics, so that the
combination of the two layers can offset the inherent defects of
each material to assure protection of the water pipes against the
high temperature gas environment and abrasion.
[0090] Further, even in cases where installation is performed in
stoker type incinerators, which generate temperatures of 900 to
1200.degree. C. around the openings, installing a double-layered
fireproof structure according to the present invention can prevent
damage derived from differences in thermal expansion rates as well
as declines in the structure's durability.
[0091] Further, by providing the foregoing hanging members which
support the aforementioned fireproof tiles on the water pipes,
forming the flow path for the cooling water, there is no concern
for heat damage to the hanging members, because they are cooled.
Further, the foregoing hanging members, being L-shaped hanging
members, are prevented from being directly exposed in the
combustion gas environment, which prevents the hanging members from
being over-heated.
[0092] Also, setting the thickness ratio between the foregoing
fireproof castable and the fireproof tile to about 2:1 to 3:1, or
the ratio of the thickness of the foregoing castable and the radius
of the foregoing water pipe to 1+.alpha.:1, with
.alpha.=approximately 0.1 to 0.3, assures that the water pipes are
protected and at the same time improves the durability of the
support members.
[0093] Furthermore, production can be simplified and costs can be
lowered by using flat tiles for the foregoing fireproof tiles, and
this additionally simplifies their installation.
[0094] Further still, one can simplify the installation process
over water pipes having complex shapes by using cladding deposit or
thermal spraying deposit for the inner protective layer for water
pipes and a fireproof castable for the outer protective layer to
realize a higher durability, abrasion resistant, and highly
fireproof structure.
* * * * *