U.S. patent number RE29,622 [Application Number 05/772,610] was granted by the patent office on 1978-05-02 for apparatus and process for pellet preheating and volatile recycling in a glass making furnace.
This patent grant is currently assigned to Pullman Incorporated. Invention is credited to Karl H. Lange.
United States Patent |
RE29,622 |
Lange |
May 2, 1978 |
Apparatus and process for pellet preheating and volatile recycling
in a glass making furnace
Abstract
A glass making furnace having a preheater and recycling
structure including a tubular housing having a lower gas receiving
stack section, a top in the form of an inverted cone, a glass batch
pellet containing intermediate section, having a lower portion over
the cone and about the intermediate section, gas ports in the side
of the cone, shield means over the ports, a discharge valve in the
lower portion below the cone part, a hot gas stack extending over
the upper portion of the pellet section, a fan or hot gas ejector
at the top of the stack, a damper above the fan or hot gas ejector
connecting with a pressure controller within the furnace for
maintaining the pressure in the furnace slightly above atmospheric,
an inlet valve outwardly of the upper portion of the pellet section
to control the entrance of the pellets, a regenerator on each side
of the melting section and port and burner means communicating with
each regenerator, a reversing valve connected with the regenerators
and the melting section, and a portion of the reversing valve
connected with the cooler outside air and the regenerator being
fired.
Inventors: |
Lange; Karl H. (Allison Park,
PA) |
Assignee: |
Pullman Incorporated (Chicago,
IL)
|
Family
ID: |
24399628 |
Appl.
No.: |
05/772,610 |
Filed: |
February 28, 1977 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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386112 |
Aug 6, 1973 |
|
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Reissue of: |
599440 |
Jul 28, 1975 |
03953190 |
Apr 27, 1976 |
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Current U.S.
Class: |
65/27; 55/479;
65/335; 432/180; 432/215 |
Current CPC
Class: |
C03B
3/023 (20130101); Y02P 40/50 (20151101) |
Current International
Class: |
C03B
3/02 (20060101); C03B 3/00 (20060101); C03B
005/16 () |
Field of
Search: |
;65/335,27,160
;55/77,99,390,478,479 ;432/72,179,180,215 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kellogg; Arthur D.
Attorney, Agent or Firm: Myers; Richard J.
Parent Case Text
This is a continuation of Ser. No. 386,112, filed Aug. 6, 1973, now
abandoned.
Claims
I claim:
1. A pellet preheater adapted to receive the exiting combustion
gases from a glass furnace for heating pellets to be introduced to
the glass furnace comprising
a tubular hot gas stack section adapted to being connected to
receive the exiting combustion gases from the glass furnace,
a top portion of the hot gas stack section being apertured to allow
the combustion gases to pass therethrough,
a cylindrical exhaust tube to carry gases out of the preheater,
and
a pellet containing stack section receiving and holding the pellets
while they are heated and coated by the condensate from the
combustion gases, said pellet stack section surrounding the hot gas
stack section and the exhaust tube and including a lower portion,
above that a reduced portion and above that a top section,
the lower portion of the pellet stack section surrounding the top
portion of the hot gas stack section and including a discharge
valve to allow discharge of the heated pellets from the
preheater,
the top section of the pellet stack section surrounding the exhaust
tube and including an intake valve to admit pellets to the
preheater,
the reduced portion of the pellet stack section joining the top
section and the lower portion of the pellet stack section and
surrounding the exhaust tube, said reduced portion including an
inwardly and downwardly sloping surface to heat the pellets by
contact with the exhaust tube and the sloping surface of said
reduced portion.
2. A pellet preheater as claimed in claim 1 wherein there is a fan
connected to the exhaust tube to draw the exiting gas out from the
pellet stack section of the preheater.
3. A pellet preheater as claimed in claim 1 wherein the intake
valve and the discharge valve have the form of inverted cone-shaped
surfaces to control the passage of pellets therethrough.
4. A pellet preheater as claimed in claim 1 wherein a downwardly
and outwardly sloping surface connects the reduced portion and the
lower portion of the pellet stack section to allow the lower
section to have a greater volume capacity so as to allow for
maximum contact between the combustion gas and the pellets. .Iadd.
5. The combination of a glass melting furnace having an exhaust
duct,
a pellet preheater having a hot gas stack section connected to said
duct whereby any hot gasses may filter through any pellets in the
preheater,
a pressure controller within said furnace,
valve means for regulating the exhaust discharge from said stack
section,
and means operatively connecting said valve means with the pressure
controller for maintaining the pressure in the furnace slightly
above atmospheric, and concurrently coordinating selected pressures
in the furnace and in the preheater,
and fluid circulating means upstream said valve means for causing
increased movement of gas through the exhaust duct. .Iaddend..Iadd.
6. The invention according to claim 5 and said valve means
comprising a damper. .Iaddend..Iadd. 7. The combination of a glass
melting furnace having an exhaust duct,
a pellet preheater having a hot gas stack section connected to said
duct,
a pressure controller within said furnace,
valve means for regulating the exhaust discharge from said stack
section,
and means operatively connecting said valve means with the pressure
controller for maintaining the pressure in the furnace slightly
above atmospheric,
said stack having an outlet portion, and
an exhaust fan positioned in said outlet portion, and
said valve means comprising a damper positioned within said outlet
portion downstream of the fan,
said damper including means for developing static pressure against
the fan.
.Iaddend..Iadd. 8. A glass making furnace having a preheater and
recycling means including a tubular housing having a lower gas
receiving stack section, a top in the form of an inverted cone, a
glass batch pellet containing intermediate section, having a lower
portion over the cone and about the intermediate section, gas ports
in the side of the cone, shield means over the ports, a discharge
valve in the lower portion below the cone part, a hot gas stack
extending over the upper portion of the pellet section, a hot gas
ejector at the top of the stack, a damper above said ejector, a
pressure controller within the furnace operatively connected to the
damper for maintaining the pressure in the furnace slightly above
atmospheric, an inlet valve outwardly of the upper portion of the
pellet section to control the entrance of the pellets, a
regenerator on each side of the furnace, said furnace having a
melting section between said regenerators, ports in the furnace and
burner means communicating with the regenerators, a reversing valve
connected with the regenerators and the melting section, and said
reversing valve having a portion connected with the relatively
cooler outside air and the regenerator being instantly fired.
.Iaddend..Iadd. 9. The invention according to claim 5 and said
pellet preheater being disposed in series between the furnace and
said stack section and operative to extract heat from gasses
passing therethrough whereby the gasses downstream thereof are
cooler and upstream thereof, and
said fluid circulating means including a fan and said valve means
being cooperative with said fan and developing back pressure within
the stack. .Iaddend..Iadd. 10. The invention according to claim 5
and a regenerator on each side of the furnace, said furnace having
a melting section between said regenerators, ports in the furnace
and burner means communicating with the regenerators, a reversing
valve connected with the regenerators and the melting section, and
said reversing valve having a portion connected with the relatively
cooler outside air and the regenerator being instantly fired.
.Iaddend. .Iadd. 11. An improved process of making glass in a
furnace having a main furnace melting section and a preheater and
recycling structure comprising a glass batch pellet containing
section communicating with said main furnace section, the steps
of;
a. circulating heated gasses from the main furnace section through
the glass batch pellet containing section; and
b. maintaining the pressure in the furnace slightly above
atmospheric pressure by throttling the exhaust of gasses from the
furnace downstream of said glass batch containing section and
thereby increasing recirculation of the gasses through said glass
batch containing section.
.Iaddend..Iadd. 12. The process according to claim 11 and
controlling the throttling in response to variations in pressure in
the main melting section of the furnace. .Iaddend..Iadd. 13. The
process according to claim 12 and heating the main furnace melting
section by regenerators on each side thereof and controlling the
heating by a reversing valve connecting the regenerators and main
furnace melting section with cooler outside air and the regenerator
being fired. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates to the field of refining of molten raw
material and in particular to the field of glass manufacturing, and
more particularly relates to structure for the introduction of the
glass producing ingredients into the glass making furnace.
2. Description of the Prior Art:
It is known in the prior art to provide for the preheating of
pulverous materials used in the manufacturing of glass where such
pulverous material is preheated by the fumes above the molten batch
in the furnace, as for instance, see U.S. Pat. No. 3,172,648.
However, it is desirable to provide for a preheater arrangement
which allows for the hot gases above the molten bath of glass to be
circulated through the glass making material so that the products
of combustion and other volatiles are allowed to condensate out on
the glass making material as the heat is given up by the hot gases
from the glass manufacturing furnace. The benefits are three-fold
in that the condensates are reused and that the condensates are not
sent out into the atmosphere eliminating or greatly reducing air
pollution and lastly that the charge is preheated. This is what the
invention endeavors to accomplish.
SUMMARY OF THE INVENTION
This invention relates to the preheating of pelletized material
used in the manufacture of glass wherein the heating of the
pelletized material is caused by the vaporized products,
dissociated products, carryover products or other products of
combustion above the molten bath of glass which hot gases pass
through the pellets of silica and other material used in the
manufacture of glass.
It is a general object of this invention to provide for a
preheating stack in communication with outlet means of the glass
making furnace and which stack carries heat transfer modules such
as pellets of silica or sand or the like material which pellets
have their surfaces exposed to the volatile gases from the melting
furnace and which volatile gases condensate out on the surfaces of
the pellets so that the pellets are not only heated by the warm
gases but are also coated with condensates which may be used in the
manufacture of glass and which are not introduced into the outside
atmosphere and thus air pollution is reduced.
Another object of this invention is to provide for a preheater of
tubular stack design having a low tubular section and having an
upper cone portion perforated for introducing hot gases into
pellets of glass manufacturing material suspended above the cone in
an intermediate tubular stack section about the cone wherein the
intermediate pellet containing section has an outlet valve below
the cone and an upper inlet valve outwardly of an exhaust stack
allowing separation of the gases from the pellets for discharge of
the relatively cleansed gases into the atmosphere.
It is another object of this invention to provide for a damper at
the top outlet or exhaust above the preheater fan blower or hot gas
ejector wherein the damper is movable in response to a pressure
control unit within the furnace above the molten bath in order to
maintain the pressure in the furnace slightly above atmospheric
pressure.
These and other advantages will become apparent from reference to
the following description, appended claims and attached
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the glass making furnace, the
sand pellet preheater unit, and the hopper and conveyor structure
for dispensing of the batch material of silicious glass batch or
the like and the cullet of broken pieces of glass and the pellets
of silica and other material;
FIG. 2 is a plan view partially in section and similar to FIG.
1;
FIG. 3 is an end view of the glass manufacturing furnace, the
pellet preheater, and the hopper and conveyor apparatus for
transferring of the material for manufacturing glass;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3 and
showing the pellet preheater; and
FIG. 5 is a sectional view of the preheater showing the interface
cone between the pellets and the furnace hot gases and taken along
line 5--5 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings and in particular with reference
to FIGS. 1-3, there is shown a glass manufacturing furnace 2 having
a dog house 3 for receiving the silica glass batch or other
material, a furnace melting portion 4 including a furnace interior
4a containing the glass batch of molten material 5. The furnace
melting portion 4 is provided with ports 6 and with burners 8 which
spew out gas flames 7 into the furnace interior 4a. The ports 6
communicate with the furnace regenerators or checkers 10, there
being one such regenerator or checker 10 on each side of the
furnace melting portion. As viewed in FIG. 1, the furnace is
provided with glass discharge ports 9 which allow the molten glass
to flow from the furnace. As seen in FIG. 2 the flames 7 jet out
from the burners 8. About every 15 to 20 minutes this cycle is
reversed with the lower burners 8 spewing out the flame 7 toward
the upper burners. The regenerators 10 are enlarged areas of
refractory material having passages therein which allow air to be
introduced into or from the interior 4a of the furnace via the
ports 6. While cooler outside air is being introduced through the
checker 10 on the right as viewed in FIG. 3 by way of the reversing
valve 11 from the outside via air duct opening 12, the reversing
valve 11 also permits spent gases from the interior 4a to pass
through the ports 6 on the left side of the furnace and out the
regenerator 10 on the left side and through the flue line 13 on the
left side and via the reversing valve into the glass batch pellet
preheater 14. Spent gases comprise the products of combustion, the
products of dissociation of raw material and the carryover (dust of
batch components). The flow of the spent gases and the combustion
air in each half of the furnace is reversed about every 15 to 20
minutes by operation of the reversing valve 11 so that the spent
gases flow out of the opposite regenerator to the preheater and the
heated combustion air flows from the other regenerator into the
furnace. The heated combustion air (which is up to approximately
2000.degree. F.) flows from the same side from which the flame
comes and enters into the melting area.
Pelletized material in the form of silica and other material is
supplied to the preheater 14 by the conveyor system 22 which in the
instant disclosure includes a top bucket conveyor 16 for delivery
of a preweighed batch of raw material components for glass making
to the left hopper or storage bin 17 as viewed in FIG. 3 along with
cullet or presized pieces of broken glass by way of header pipes
18. The right hopper 19 is a segmented hopper and may contain all
batch or one segment of divided hopper to be used for cullet
storage for delivery to the furnace. The batch in the hopper 17
goes to the gravimetric feeder arrangement 20 to the pelletizer 21
which makes pellets which are transferred by pellet conveyor 22 to
the top of the preheater unit 14. A dual purpose conveyor 23 may be
used primarily to supply cullet to the modified blanket batch
feeder, or any other suitable feeder, or its secondary function may
be to feed mixed raw batch directly to the feeder when bringing the
pelletizing-preheating facility into production or taking unit out
of production for inspection and/or maintenance. As seen in FIG. 1
a belt conveyor 25 supplied the heated pellets from the preheater
to the charger 24 for loading the dog house 3. Thus it is seen that
the glass making furnace may be supplied with either standard glass
batches of sand and respective components, cullet, or pellets of
glass batch and cullet.
The pellet preheater unit is placed in the path of the hot gases
exiting from the regenerators for warming of the glass batch
pellets and depositing in the form of condensates the volatile
material and dust picked up by the flame fronts moving above the
molten bath. The pellet preheater unit 14 is interconnected with
the hoppers 17 and 19 by walks 26 and 27 and ladder 28. The pellet
preheater unit 14 comprises a lower stack or pipe section 29 (see
FIG. 4) which receives the products of combustion such as the
volatiles and fine particles from the furnace interior via the flue
13 that communicates with the hot gas exiting from the proper
regenerator due to the positioning of the reversing valve 11. This
hot gas contained in stack section 29 is provided with a cone top
section 30 provided with a plurality of apertures 31 that have hood
members or shields or protective ramps 32 thereover to prevent
pellets from entering the apertures 31 from above and falling into
the hot gas stack section 29. Extending above and having its lower
portion 33 extending over the cone top portion 30 is a pellet
containing tubular or stack section 34 which is also tubular shaped
and in addition to the lower portion 33 has an upper reduced
portion or annulus part 35 reinforced by struts 36a. Pellet stack
section 34 is further provided with a top section 36 that has lower
inwardly downwardly sloping wall 37 and upper inwardly upwardly
sloping wall 38 that connects with pellet entrance pipe 39 that has
a conical valve and seat arrangement 40 to control the flow of
pellets into the pellet section 34. The lower portion 33 of the
pellet section 34 is provided with a lower end part 41 that extends
around the hot gas stack section 29 and connects with the discharge
cone valve arrangement 42 which is like the inlet conical valve
arrangement 40 and permits discharge of the pellets from the pellet
section 34 onto the pellet conveyor 25. The top part 36 of the
pellet section 34 is provided with a blower fan housing 43 having a
blower fan 44 therein for delivery of the gases upwardly out of
flue exiting stack 45 to the atmosphere. By this arrangement the
condensates are stripped from the exiting flue gases and stored on
the outer surfaces of the pellets which are also heated by the warm
gases so that as the flue gases exit into the atmosphere they are
cooler. The gases in the hot gas stack 29 range from 1000.degree.
F. to 1600.degree. F. and gradually become cooler as they are drawn
through the pellet section 34 and in the area of the fan 44 the
products of combustion are generally in the area of 600.degree. F.
or lower and these products of combustion exit from the outer flue
stack 45 at approximately 450.degree. F. or less.
The slope wall 37 allows the pellets to come in contact with the
metal surface of the pellet stack section to further heat the
pellets, and the cone valves at the entrance and exit portions of
the preheater provide for even distribution of the pellets for even
discharge feeding. The pellets in the pellet section 34 provide
about a 44 percent packing void to provide for adequate surface
contact between the condensates and the pellets and further provide
for adequate heat transfer from the hot gases to the pellets. The
cylindrical exhaust inlet tube 46 connecting with the fan housing
43 and extending into the top of the pellet section 34 has its
bottom portion adjacent the cone part 30 and aids in conducting the
gases out the upper stack portion 45. This preheater unit provides
for savings in heat loss and in loss of condensates of the products
of combustion.
Above the furnace melting portion 4 on the interior walls of the
furnace 2 there is provided a pressure indicator and controller 14b
which senses the pressure above the molten material 5 within the
furnace 2 and in turn operates the damper or valve 14a which is
located in the preheater unit across the upper stack portion 45
above the blower fan 44 .Iadd.or gas circulating means
.Iaddend.(see FIG. 4). The furnace atmosphere pressure control 14b
includes the conventional gaseous pressure indicating device and
pressure responsive controller arrangement which operates a drive
motor to open and close the damper 14a. This controller 14b
controls the pressure within the furnace within limits which are
above atmospheric pressure. The approximate range is from 0.005 to
0.15 inch of mercury above atmospheric pressure, wherein every
atmosphere of pressure is 14.7 psi or 27.8 inches of mercury. This
controller 14b prevents the development of negative pressure or
pressure below atmospheric pressure so that fuel will not be wasted
by attempting to warm and act upon the infiltration of cold air.
The locating of the damper 14a above the fan 44 takes into
consideration the collection of the condensates in the pellets and,
therefore, as the pressure in the furnace above the molten bath
would decrease this would cause increased opening of the valve or
damper 14a to maintain a draft or positive pressure on the furnace
because otherwise we would be introducing the preheater to
atmospheric pressure. The range of 0.005 to 0.15 inch of mercury
meets the necessary furnace requirements and with the valve above
the pellets being open the fan is allowed to become more efficient
and less cavitation develops. It is desirable to have a back
pressure against the fan to maintain a controlled pressure above
the bath pressure but if the valve or damper would be below the
pellets there would be fluidizing of the pellets during loading of
the pellets in the preheater. This fluidizing will not occur if the
valve or damper is above the fan to put static pressure against the
fan. An emergency stub stack 13a (see FIG. 1) connects with the
exhaust tubing 13 and is provided with a damper 13b to operate as
an emergency furnace pressure control. This valve or damper 13b
allows excessive pressure to be exhausted from the furnace.
The glass making furnace may not in all cases be limited to the
regenerative type furnace only.
Preheating of the pellets includes not only an increase of
temperature of the pellets but also any accompanying change in the
physical or chemical state of the pellets as a result of preheating
such as the formation of a eutectic phase in the pellets.
The foregoing description and drawings merely explain and
illustrate the invention and the invention is not limited thereto,
except insofar as the appended claims are so limited, as those
skilled in the art who have the disclosure before them will be able
to make modifications and variations therein without departing from
the scope of the invention.
* * * * *