Note: Descriptions are shown in the official language in which they were submitted.
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Field of the Invention
The present invention relates to a furnace system to
melt an array of solid materials such as refractory and some
metals.
Background of the Invention
The prior art is replete with various types of furnaces
to melt metals or refractory. These furnaces, generally, are
those small and medium size units used in general foundry
practice, heat treating and associated processes. Larger units
are generally used for melting large quantities of metal or
refractory as part of specific production processes such as the
production of high purity alloy steels, processing batches of
processes parts receiving vitreous enamel, annealing glass, and
so on.
As such, each furnace is,. normally, designed for a
specific industry and, thus, purposes. For example, there are
various types of furnaces, two of which are arc furnaces and
submerged resistance. In arc furnaces heat is developed by an
arc, or arcs, drawn either to a charge or above the charge.
Direct arc furnaces are those in which the arcs are drawn to the
charge itself. In indirect arc furnaces the arc is drawn between
the electrodes and above the charge. A standard power frequency
is used in either case, direct current (DC) electric power is an
alternative source of energy.
In resistance furnaces of the submerged arc type, heat
is developed by the passage of current from electrode to
electrode through the charge. The
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manufacture of basic products, such as container glass,
mineral wools, ceramic fiber and fiber glass, is the
general service of a submerged resistance furnace.
Alternating current (AC) at a standard power frequency
is used.
Moreover depending on the purpose, the furnace may
be a bottom pour, side pour or both ("pour
configuration"); electrically configured for either low
voltage, higher current in Delta, or higher voltage,
lower current in the Wye ("electrical configuration");
and power regulation in either AC or DC.
None of the prior art patents describe a furnace
able to change its pour configuration, electrical
configuration, melting options and power regulation
(collectively referred to as "Configurations") to
determine the ultimate furnace for a particular material
or process.
Summary of the Invention
The present invention is a multi-faceted furnace
apparatus. The apparatus has a furnace system, an
electrical system, a positioning system and control
unit. The furnace system has a set of movable
electrodes, and at least two pour configurations, to
transform a solid material into a molten state. The
electrical system provides the electrode with a
predetermined, yet changeable type of regulation,
current, voltage, impedance, power, and/or imbalance of
current. While the electrode positioning system moves
the electrode, this movement determines if the electrode
is properly positioned for the furnace to be an open arc
system, a submerged resistance system or submerged arc
system. The above systems are monitored by the control
unit. There by the furnace system, the electrical
system and the positioning system can all be altered to
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achieve the most efficient and cost saving method to
transform the solid material into the molten state.
Brief Description of the Drawings
Figure 1 is a side view of the present invention.
Figure 2 is an exploded view of Figure 1.
Figure 3 is a side view of Figure 1.
Figure 4 is a schematic of the electrical system.
Figure 5 is a schematic of the gas exhaust system.
Figure 6 is a schematic of the water system.
Figure 7 is a schematic of the positioning system.
Detailed Description of the Present Invention
FIG. 1 shows a preferred embodiment of a furnace
apparatus 10. In the preferred embodiment, the furnace
apparatus 10 is a mobile unit having a platform 9 and a
housing 11. The housing 11 is subdivided with furnace
access doors 8, operator doors 7, operator console doors
6, electrical system access panels 5, and other sections
4, including the roof. A raising apparatus 3 elevates
the apparatus 10, in particular the platform 9, a
minimum distance above the ground, such as by wheels,
blocks, or the like. Preferably, the apparatus 10 is
designed to be transported. As such, the dimensions of
the apparatus 10 allow it to be mounted onto a tractor
trailer bed 2 and be transportable on the interstate
highway system, i.e., under overpasses and without
requiring additional highway permits.
Turning to Figure 2, the apparatus 10 has the
housing 11, a melter/electrode positioner unit 12, a
power regulation supply 14, a controller unit 16, a data
acquisition system 170, a motor control system 18, a
dust collecting system 20, a water cooling system 22,
and a multi-faceted furnace 24. The controller unit 16
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displays operational data from the other subsystems 12,
14, 18, 20, 22, 24. Each subsystems 12, 14, 18, 20, 22,
24 interconnects to the data acquisition system
(hereafter "DAS") 170. The data system 170 collects and
monitors this information and displays the results at
the operator console unit 16. The user, not shown,
through the console unit 16 and various manual override
switches operates each subsystem 12, 14, 18, 20, 22, and
24, to change the apparatus' 10 Configurations. There
are over 90 different configurations that can be set _
within a predetermined time frame. Depending on the
Configuration change the time frame ranges between
seconds to about four hours. By changing the
Configurations, the user alters the function of the
furnace 24 to obtain the ultimate furnace qualities for
a particular material. Likewise and alternatively, the
DAS 170 operates, by the user's discretion, the
apparatus 10 by comparing previous inputs from each
subsystem 12, 14, 18, 20, 22 and 24 to the present
readings, and alters each subsystem to obtain the
maximum and desired Configuration.
The foundation for apparatus 10 is the furnace 24.
The furnace 24 receives a material, commonly called a
charge, i.e., a metal, a refractory or an alloy. The
furnace 24 melts it (to be described later), and then
pours the molten material. The furnace 24, as shown in
Figure 2, has a conical top portion 26, a cylindrical
middle portion 28 and a rounded bottom portion 30. Each
portion 26, 28, 30 is insulated with conventional
furnace insulation material, not shown, to retain its
heat. On the exterior of the furnace 24, the furnace 24
has an operator door 36, various position apertures 38,
an exhaust aperture 40, and two pour configurations 32,
34. In one embodiment, the conical top portion has a
manifold 930 that reflects some of the heat generated in
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furnace 24 back to the furnace 24 and allows some of the
heat to escape into the exhaust aperture 40.
The first pour configuration allows the molten
material to pour out a side spout 32 of the middle
portion 28; the second pour configuration, turn to
Figure 3, allows the molten material to pour out the
bottom orifice 34 at approximately 12" from the nadir of
the rounded bottom portion 30.
When the respective spout and orifice 32, 34, are
open, the flow rate of the molten material is monitored
by load cells 23. Each load cell 23, positioned about
the furnace 24, generates a signal 200 proportional to
the weight of the furnace and its charge. The DAS 170,
as shown in Figure 4, receives the signal 200, wherein
the console unit 16 illustrates the results. As time
passes, the difference in weight provides a method to
calculate the flow rate of the molten material.
Returning to Figure 3, when the furnace 24 operates
with any material, molten or solid, within it, the
furnace 24 generates gases. As shown in Figure 5, those
gases 82 exit to the dust collecting system 20. While
in the system 20, the temperature and velocity of the
gases 82 are measured by a plurality of thermocouples
53a and air velocity instruments 51 respectively
interspaced throughout the collecting system 20. The
dust collecting system 20 draws the gases 82 into the
aperture 40, at or about the apex of the top conical
portion 26, into exhaust ducts 42 that leads to a
cyclone 44. The cyclone 44 collects any particulate
over a predetermined size. From the cyclone 44, the
dust collecting system 20 further draws the gases
through the exhaust ducts 46 into an exhaust/filter/dust
bag house 48.
The bag house 48, preferably, has a high
temperature filter 49 to collect pre-determined
particulates, a compact fan 50, and an outlet 52. The
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system 48 is designed to insure that the gases emitted
into the local environment, from the outlet 52, meet,
and preferably exceed, any environmental output
regulations under research and development restrictions.
The fan 50 is an industrial exhaust fan that draws
the gases 82 from the furnace 24 through the outlet 52
into the environment. In the preferred embodiment, the
fan 50 draws the gases from at least 25 feet. As such,
the fan 50 must have sufficient capacity to draw these
gases from the furnace 24. The amount of power depends
on the air system leakage rate. This leakage rate is
defined, in general terms, as the more the air system
allows external air in, the harder it is to draw a
vacuum on the furnace gases.
As shown in Figure 4, the fan 50, thermocouples
53a, and air velocity instruments 51 interconnect with
the console 16 and the DAS 170. The instruments 51, 53a
transmit their respective measurements 212, 214a to the
DAS 170 and, in return, to the console 16. The console
16 shows the measurements on a touch screen display unit
100. The flow rate of the fan can be altered, allowing
more or less cooling to occur and thus effect the gas
temperature.
To further control the temperature of the gases 82
in the system 20, the present invention uses the water
cooling system 22 to cool the gases 82 and other
subsystems.
Turning to Figure 6, the water cooling system 22 is
an open system that circulates water, or any other
coolant liquid, through water pipes 52. The water pipes
52 direct the liquid, by a centrifugal pump 55, through
a cooling tower 54 that cools the liquid in the pipes 52
to a "cooled state". While in the cooled state, the
liquid traverses, and thereby cools, the dust collecting
system 20; in particular around the aperture 40, the
exhaust pipe 42 and the cyclone 44; and the furnace 24.
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The operator can alter the liquid path through various
interspaced flow meters 199, that are in a manifold
arrangement. After cooling the various subsystems, 14,
20, 24, the liquid is in a "warm state." The warm
liquid returns through the pipes 52 through the cooling
tower 54 so it can return to its "cool state."
The cooling system 22 also has nozzles 56 attached
thereto and each nozzle 56 directs the cooled liquid to
the exterior shell of the furnace 24. The nozzles 56
ensure the furnace 24 does not overheat while operating;
the liquid collects in a basin 172. A tank 174 collects
the liquid from the basin 172.
The basin 172 has a pump up/pump down system 176.
The system 176 pumps the hot liquid to pump 55 depending
on the water level in the basin 172. If the water is
high, the system 176 pumps water. In contrast, if the
water in basin 172 is low, the system 176 does not pump.
Alternatively, the cooling system 22 can be a
closed system, if a water jacket surrounds the furnace
shell.
Also within the pipes 52 are interspaced
thermocouples 53b. These thermocouples 53b measure the
temperature of the liquid, supply and return liquid.
Returning to Figure 4, the flow rate and
temperature of the liquid is controlled by the operator
through the console 16. The DAS 170 acquires data from
the pump 55 and tower 54. The pump 55 operates the flow
rate 90 of the liquid while the tower 54 outputs a fan
rate 88. The flow rate 90 and fan rate 88, in
combination with other parameters, such as variable
speed pumps or chiller systems, control the temperature
of the liquid in system 22. If the flow rate 90 is too
fast, the fan 54, at any fan rate 88, will be unable to
cool the liquid. Likewise, if the fan rate 88 is too
slow, the liquid will never cool. Controlling the fan
rate 88 and the flow rate 90 is critical to cool the
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liquid. As such, the operator, at the control unit 16
or at manual switches, transmits signals 222 and 224,
respectively, to alter the fan rate 88 and the flow rate
90.
Each thermocouple 53b transmits its measurements
214b to the console unit 16 through the DAS 170. The
console 16, in return, shows the measurements on the
display unit 100. There are provisions for the operator
to alter the fan rate 88 and the flow rate 90 depending
on the liquid temperature in the system 22.
Alternatively, each flow monitor 199 interconnects
to the DAS 170. As such, each monitor 199 transmits a
signal 220 identifying the liquid path, the pipes 52 to
the alternative pipes 52b. The alternative pipes 52b
divert the liquid from any subsystem 14, 18, 20, 24 if
the operator determines the subsystem requires a
temperature change.
Turning to Figures 4 and 6, each subsystem 14, 20,
24 has at least one thermocouple 53c, 53d, 53e, 53f, 53g
that measures the temperature of the subsystem. Each
thermocouple 53c-g performs and transmits, by respective
signals 214c-g, the relevant information to the DAS 170
and, in one embodiment, the information is displayed at
the console 16 like thermocouples 53a and 53b.
The liquid in the cooling system 22 becomes a
warmed state due to the heat generated within the
subsystems 14, 20, and particularly the furnace 24. The
furnace heat is generated in one of two ways: open arc
or submerged resistance heating. In either case, the
operator, at the console unit 16, controls the
electrical motor system 18, the melter/electrode
positioner unit 12, and the power regulator supply 14.
These three systems determine how much heat will be
generated in the furnace 24.
Turning to Figure 7, each melter/electrode
positioner unit 12 has an electrode 60, a lateral
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actuator 62, a vertical actuator 64, interconnections
66a and 66b for each actuator 62, 64, a power source 68,
and an electrode holder 70. The electrode 60 is within
the furnace 24, and connects to the distal end of the
lateral actuator 62d with the electrode holder 70. The
proximal end of the lateral actuator 62p connects to the
vertical actuator 64, located on the exterior of the
furnace 24, by electrode holder 70. As such, the
lateral actuator 62 enters the furnace through the
aperture 38. The lateral actuator 62 moves the
electrode 60 in a lateral direction.
In contrast, the vertical actuator 64 moves the
electrode 60 in a vertical direction. The lowest
position the electrode can attain in the furnace 24 is
the nadir of the aperture 38n. In contrast, the highest
position the electrode can attain in the furnace 24 is
the apex of the aperture 38a. As such, each electrode
60 can be moved in any lateral or vertical position,
relative to the aperture 38 and depending on the method
selected, open arc, submerged resistance, or submerged
arc. The positioning of the electrode is controlled by
the operator remotely at the console unit 16 or locally
at the furnace 24 and automatically controlled during
arc furnace operation to optimize the arc required. The
electrode positioner unit 12 moves by any conventional
power source. The power source can be hydraulic,
electric or air.
Returning to Figure 4, each power source 68
interconnects to the DAS 170 and the console unit 16.
The power source 68 transmits a position signal 226
identifying the position of each vertical and lateral
actuator 62, 64, and thereby the position of each
electrode 60. The console unit 16 converts that signal
into a display identifying the position of each
electrode 60 in the furnace 24. The operator reviews
the position of each electrode 60 and transmits the
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signal 226 to each power source 68 to move a particular
electrode 60 to a desired position. Alternatively, the
position of each electrode 60 can be manually controlled
by a local operator switch unit 92. Switch unit 92
allows the operator to bypass the console unit 16 and
move the electrodes 60.
Controlling the position of each electrode 60, in
itself, does not control the amount of heat generated in
the furnace 24. Each electrode 60 is controlled in
three ways; at the furnace 24, at the console 16, and .
automatic control during arc furnace operation. Rather,
the position of the electrode 60 along with the amount
and type of power transmitted to the electrodes 60
determines the amount of heat. The amount of power is
determined by the power regulating system 14.
Each system 14, 18 interconnects to the data system
170, the console unit 16, and each electrode 60. The
system 14 provides the electrode 60 with either AC or DC
current through line 250. The current can be generated
within the housing 11 or, alternatively, received from
an outside source (not shown). The system 14 transmits
an AC or DC signal 228 to the DAS 170 identifying which
mode of regulation the electrode 60 is receiving. The
operator, at the console unit 16, terminates the current
to the electrode or alters the mode of regulation being
received by the electrode 60 by transmitting a return
signal 228 to the system 14. Alternatively, there is a
manual switch 182 that allows the operator to manually
alter the current received by the electrode and/or
terminate the electrode from receiving any type of
current, and add reactance to the system during arc
furnace operations.
The power regulator system 14 provides regulated
power to the electrode 60 and operator console 16
provides the adjustment to establish the level of
voltage, current, wattage, impedance, and imbalance
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current or imbalance of power to'the electrode 60. The
motor control system 18 consists of various electrical
systems that control and monitor these various
parameters, and transmits a control signal 230 for each
parameter to the DAS 170 and the console unit 16. The
operator, at the console unit 16, monitors each
parameter and adjusts them accordingly from the console
unit 16. Alternatively, the operator can manually
adjust each parameter by a manual override switch 184,
and even shut off, the parameters being sent to each
electrode 60.
The display unit 100, alternatively, is a touch
screen unit having a readout system and allowing the
operator to view and alternatively control (and adjust)
a single measurement or parameter, or a plurality of
measurements and/or parameters simultaneously.
Alternatively, the display unit 100 is a combination of
the two embodiments to control (and adjust) and view the
parameters and measurements of the apparatus 10.
The data acquisition system 170 is, but not limited
to, a Pentium° based computer system with an array of
analog to digital converters and pulse signal to digital.
converters. This array of signal processing units held
within the computer adapts the various raw sensor
signals for display locally at the DAS 170 and remotely
at the display unit 100 which is mounted on the console
16.
Numerous variations will occur to those skilled in
the art. It is intended therefore, that the foregoing
descriptions are only illustrative of the present
invention and that the present invention be limited only
by the hereinafter appended claims:
