Note: Descriptions are shown in the official language in which they were submitted.
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There are many systems for removing molten slag from wet bottom
boilers. ~ost of these systems utilize hori~ontal tap holes (parallel to
the boiler floors). ~Solten slag flows through these tap holes and into
water filled tanks, which by the chilling effect of cool water causes the
molten slag to solidify and disintegrate into a course granular product.
The resultant black slag particles are discharged hydraulically at regular
intervals fro~ the slag tanks.
However, due to the load changes, combustion conditions or the
type o~ coal the boiler is fueled with, the ~olten slag sometimes tends to
thicken and become "gummy" causing the tap holes to close. This creates a
most serious problem and many man-hours of labor are presently spent in
reupening closed horizontal tap holes to insure maintaining a boiler in
service.
Examples o~ various for~s o~ slag removal systems previously
known are disclosed in the following U. S. patents:
Pat. Nos. 545,001 - Aug. 20, 1895 - VanCleve et al.
2,149,688 - Mar. 7, 1939 - Schott
2,548,656 - Apr. 10, 1951 - Dolezal
2,667,848 - Feb. 2, 1954 - Silk
3,133,804 - May 19, 1~`64 - Hardgrove
3,395,9g5 - Aug. 6, 1968 - Burch
3,741,136 - June 26, 1973 - Stookey.
The main object of this invention is to provide a slag removal
system which will substantially reduce the existence of dangerous conditions
which occur when slag tap holes become clogged.
Another object of this invention is to provide an improved slag
removal system const~ucted in a manner whereby slag tan~ explosions
resulting in excessive damage to plant machinery and injury to personnel
may be substantially eliminated.
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The above objects are met by the present invention
~hich broadly provides in combination, a wet bottom furnace
including a bottom wall having en elevated section thereof
defined by at least one upstanding peripheral wall portion
defining an opening therethrough adjacent the bottom wall and
defining a vertical tap hole in front of which granular material
may be deposited for damming thei vertical tap hole against the
flow of molten slag therethrough from the interior of the
furnace, the furnace bottom wall including wall means defining
a downwardly opening compartment exteriorly of the urnace into
which the tap hole opens from the interior of the furnace, and
closure means operatively associated with the wall means and
shiftable into and out of position closing the lower portion
of the compartment.
The present invention will now be described with
reference to the drawings wherein:
Figure 1 is a fragmentary, vertical sectional view of
the floor of a wet bottom boiler and with a first form of multi-
purpose slag removal system of the instant invention operatively
associated therewith;
Figure 2 is a horizontal sectional view taken substan-
tially upon the plane indicated by the section line 2--2 of
Fig. l;
Figure 3 icl an enlarged, fragmentary, vertical sectional
view illustrating one of the dozer blade support structures;
Figure 4 is a horizontal sectional view taken substan-
tially upon the plane indicated by the section line 4--4 of
Fig. 3;
Figure 5 is a fragmentary, enlarged, horizontal sec-
sectional view of the central portion of Fig. 2 and illustrat-
ing the positional relationship of the dozer blades and nozzle
heads;
Figure 6 is ~ fragmentary, enlarged, vertical sectional
view
.
sa/~ 2-
illustrating the manner in which the dozer blades may be utilized to form
a cavity in the central portion f the chilled particles bed for solid
tapping;
Figure 7 is an enlarged, fragmentary, vertical sectional view similar
to Fig. 3 but illustrating the support structure for the water nozzle heads;
Figure 8 i3 a vertical sectional view illustrating a second form of
multi-purpose slag system constructed in accordance with the present invention;
and
Figure 9 is a top plan view of the assemblage illustrated in Fig. B.
Referring now more specifically to the drawings, the numeral 10
generally designates a wet bottom boiler whose bottom 12 includes a raised
portion 14 defining a vertical tap hole 16 toward which the bottom 12
slopes. The vertical tap hole 16 opens horizontally into a compartment 20
disposed below the raised portion 14 and the compartment 20 is selectively
closeable at its lower end by means of a pivoted and counterbalanced gate
22 which may be water cooled and have sand or chilled solidified slag
particles 24 disposed thereon in order to seal the compartment 20 from the
neck 26 of a slag tank assembly referred to in general by the reference
numeral 28 disposed below the compartment 20.
The interior walls of the neck 26 diverge downwardly and the
lower end of the neck 26 is telescoped into the upwardly opening neck 30
of the slag tank assembly top wall 32 and a water seal 34 is established
between the lower end of the neck 26 and the neck 30.
The slag tank assembly 28 includes four depending cylindrical
tank sections 36 opening upwardly into a cylindrical upper tank portion 38
immediately below the top wall 32 and the tank sections 36 depend downwardly
from four equally peripherally spaced portions of the bottom wall 40 of the
upper tank portion 38, the bottom wall 40 including a central raised cylin-
drical platform 42 about which the upper seat defining upper portions 44 of
the tank sections 36 are disposed.
A closure 46 in the form of a float is provided and includes a
seating surface 48 selectively sealingly engageable with any of the seat
defining upper portions 44 of the tank sections 36. Further, the lower
ends of the tank sections 36 are closed by means of inverted conical lower
end portions 50 and each conical lower end portion 50 includes a door 52
formed therein through which solidified slag particles may be removed from
the tank sections 36.
Any suitable means, such as a valve controlled outlet 54, may be
provided for draining water from the upper tank portion 38 and suitable
means, such as a water inlet conduit 56, may be provided for admitting
water into the upper tank portion 38. Further, suitable means, not shown,
is provided for admitting water into each tank section 36.
lhe closure 46 may be shifted from a position closing the upper
portion of one tank section 36 to a position closing the upper portion of
another tank section 36 merely by raising the level of water within the
upper tank portion 38 whereby the closure 46 may be floated out of position
engaged with a seat defining upper portion 44 of one of the tank sections
36. Then, the closure 46 may be floated into position above the seat
defining upper portion 44 of a second tank section 36 and the level of
water within the upper tank portion 38 may be lowered in order that the
closure 46 may be lowered into position in seated engagement with the seat
derining upper portion 44 of the second tank section 36.
The compartment 20 includes an access port 60 opening thereinto
on the side thereof remote from the vertical tap hole 16 and solidified
slag particles 62 may be dammed up in front of the vertical tap hole 16
through the port 60 and sand and/or solidified slag particles 24 may be
placed on top of the gate 22 through the access port 60.
Referring now more specifically to Figs. 1 and 3-6 of the
drawings, it will be seen that four dozer blade assemblies referred to in
general by the reference numeral 64 are operatively associated with the
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platform 42. Each dozer blade assembly includes a support 66 supported
from the top wall 32, a double acting fluid cylinder 68 supported atop
each support 66~ a piston rod 70 depending from each cylinder 68 and
extendible and retractable as well as rotatable relataive to the latter
and a rotatable and vertically slotted frame 72 supported from each
support 60 and oscillatable about an axis concentric with the corresponding
piston rod 70. Each piston rod 70 includes a pair of diametrically oppo-
site and outwardly projecting flanges 74 slidingly received in the slotted
portions of the frame 72 and each frame 72 has the piston roa 76 of a
second double acting fluid motor 78 pivotally anchored thereto as at 80,
each double acting fluid motor 78 being oscillatably supported from the top
wall 32 or other stationary support.
The lower end portions of the piston rods 70 project downwardly
through openings 82 formed in the top wall 32 and terminate downwardly
in horizontal dozer blades 83 which are swingable between the solid and
phantom line positions thereof illustrated in Fig. 5 upon extension and
retraction of the corresponding fluid cylinders 78. Further, the piston
rods 70 may be extended and retracted in order to raise and lower the
dozer blades 83.
In addition to the dozer blade assemblies 64, there is also
provided four pairs of spray head assemblies 84 similar to the assemblies
64 and including supports 86~ Cylinders 88 corresponding to the cylinders
68 are supported from the supports 86 and the cylinders 88 include depending
piston rods 90 and oscillatable frames 92 corresponding to the frames 72
are supported from the supports 86 for oscillation about axes concentric
with the piston rods 90. The piston rods 90 include diametrically opposite
and outwardly projecting flanges 94 corresponding to the flanges 74 and
slidably received in the slotted portions of the frames 72 and the piston
rod portions 96 of double acting cylinders 98 are pivotally connected as
at 100 to the frames 92 for oscillation thereof. The piston rods 90
include water inlet ports 101 opening thereinto to which a suitably
controlled supply of water under pressure may be connected and the hollow
piston rods 90 open downwardly into horizontal hollow sprayer heads 103.
Accordingly, the sprayer heads 103 may be raised and lowered by actuation
of the cylinders 88 and may be oscillated about vertical axes by actuation
of the cylinders 98.
In operation, the dozer blades 83 may be operated in a manner
which is believed obvious from Figs. 5 and 6 of the drawings in order to
form a center cavity 110 on the platform 42 by scraping solidified slag
particles across the top of the bed of solidified slag particles disposed
on the platform 42. With the cavity 110 thus formed, the molten slag may
be tapped from the boiler 10 into the cavity 110 for solid tapping and the
solid solidifed slag may be subsequently dozed off the platform 42 and into
one of the tank sections 36 by the dozer blades 73. Although the dozer
blades 73 are illustrated in Fig. 3 in phantom and solid lines relatively
angularly displaced approximately 40 , it is to be noted that the dozer
blades 83 may be angularly displaced through a range of approximately 90.
If it is desired, the spray heads 84 are actuated during the
process of a tapping operation whereby the slag dropping onto the bed 112
will be solidified and broken up into small particles.
Further, the water level within the upper tank portion 38 may be
raised to a level above the platform 42 and in this mamler the slag being
tapped from the boiler 10 will fall down into the water above the platform
and thereafter sink to the bed 112 on the platform 42. After the slag has
solidified, it may be displaced from the platform 42 into one of the tank
sections 36. ~hen it is desired to empty one of the tank sections 36, the
closure 46 is first floated into position over that tank section 36
lowered into position sealing the upper end of that tank section 36 and
thereafter the door 52 of that tank section 36 may be opened in order to
remove the solidified slag 120 from the lower end thereof. Of course,
while one tank section 36 is sealed closed at its upper end by means of
the closure 46, solidified slag may be deposited into any one of the other
three tank sect;ons 36 and each may be successively closed at its upper
end by means of the closure 46 in order that solidified slag in the lower
portion thereof may be removed through the associated door 52.
By providing the vertical tap hole 16, it is substentially
impossible for the slag passing through the tap hole 16 to clog the
latter. Further, by providing the gate 22, tight seal may be maintained
between the compartment 20 and the neck 26.
With attention now invited more specifically to Figs. 8 and 9 of
the drawlngs, there will be seen a modified form of slag tank assembly
referred to in general by the reference numeral 128. The slag tank
assembly 128 is similar to the slag tank assembly 28 in that it includes a
neck 126 corresponding to the neck 26 and a water seal 134 corresponding
to the water seal 34. Further, the upper end of the neck 126 i8 closed by
means of a gate similar to the gate 22. Of course, the slag tank assembly
128 is utilized in conjunction with a boiler such as the boiler 10 including
a raised central portion and a vertical tap hole leading into a compartment
such as the compartment 20.
The slag tank assembly 128 includes a plurality of nozzle
assemblies 136 corresponding to the nozzle assemblies 84 and a plurality .
of chain strands 138 are arranged in depending fashion in a circular pattern
concentric with the neck 126. However, a turntable support structure 140
includes a powered rotatable and vertically shiftable central shaft 142
eccentrically disposed relative to the neck 126 and the lower end of the
shaft 142 includes a horizontal circular turntable 144. One peripheral
portion of the turntable 144 is disposed beneath the neck 126 and the
nozzle assemblies 136 and the chain strands 138 are arranged in circular
pattern concentric with the lower end of the neck 126.
The turntable support structure 140 is, of course, supported from
the top wall 132 of the tank assembly 128 and the latter includes a verti-
cally reciprocal piston rod 150 including a wedge-type lower end head 152.
The rod 150 is carried by a double acting fluid cylinder 154 supported from
the top wall 132 and the rod 150 extends and i8 slidable through the top wall
132. The spacing of the rod 150 from the center axis of the rotatable and
vertically extendible and retractable support rod or column 142 of the
turntable 144 is substantially identical to the spacing of the center of
the neck 126 from the column 142. In this manner, the driven, rotary and
extendible and retractable column 142 for the turntable 144 may be rotated
].0 at a speed whereby the molten slag deposited on the ~urntable 144 is
formed into a ribbon, which ribbon is intermittently broken up into
specified length ribbon sections by means of the wedge-shaped head 152
carried by the lower end of the rod 150 as the latter is reciprocated up
and down by means of the cylinder 154. The broken slag ribbon sections
may then be deflected off of the turntable 144 for dropping downward into
the bottom 160 of the slag tank assembly 128 and upward movement therefrom
by means of the auger conveyor 162. If it is desired, the slag tank
assembly 128 may be provided with dozer blades such as the dozer blades 83
in order to deflect the solidified slag ribbon sections from the turntable
144. Otherwise, a simple stationary deflector portion (not shown) may be
provided relative to which the turntable 144 may rotate for the purpose of
deflecting solidified ribbon sections of slag from the turntable 144.
The water level within the upper portion of the tank assembly 128
may be raised and lowered as desired by admitting and draining, respectively,
water into and from the tank assembly 138 by any suitable structure (not
shown) provided for that purpose. After a suitable bed of solidified
slag particles has been formed on the turntable 144, the water level may
be lowered in order that the molten slag may fall directly onto slag
particle bed on the periphery of the table 144 and be transformed into a
ribbon for breaking up into predetermined length ribbon sections by the
wedge-shaped head 152 at the lower end of the rod or shaft 150.
