Patent Application
20140083253
The present exemplary embodiment relates to an apparatus and method for introducing a refining agent into molten metal. It finds particular application in conjunction with a system for introducing a predetermined amount of chloride flux into a trough of molten aluminum, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Molten metals such as aluminum are known to include high levels of oxide and/or nitride debris that have a negative effect on the solidification of the particular alloy. The melted or liquefied form of aluminum also attracts the formation and absorption of hydrogen within the molten aluminum. Hydrogen evolves as porosity during the solidification of aluminum alloys and is detrimental to the mechanical properties of the solid alloy. Degassing is an effective way of reducing hydrogen caused porosity.
One example of degassing involves introducing a mixture of an inert gas such as argon or nitrogen with a reactive gas such as chlorine or sulfur hepa-fluoride into the molten aluminum to collect hydrogen and de-wet solid impurities. The gas mixture bubbles to the surface with the hydrogen and oxide impurities.
However, these materials are highly noxious and can cause harmful effluent bi-products. Improper use of these gasses creates environmental problems. Accordingly, there is significant governmental regulation. The proper storage, transport and use of these gasses is burdensome and expensive due to its harmful effects and the associated federal regulations.
Molten aluminum can also be subject to a flux degassing process. Flux degassing is the process of introducing a powdered or granulated salt mixture such as chloride and/or fluoride into the molten aluminum via a carrier gas such as nitrogen or argon. The salt flux can be introduced by a rotary degassing apparatus. An exemplary rotary apparatus includes a central hollow shaft attached to a rotor inserted into a pool of molten aluminum and rotated such that the salt flux travels down the hollow shaft and is dispersed within the molten aluminum through apertures in the rotor.
There remains a need to provide an apparatus and method to efficiently and safely handle the injection of a predetermined amount of degassing flux into the molten metal.
In one embodiment, the present disclosure relates to a flux injector apparatus adapted to distribute a predetermined amount of flux to an associated pool of molten aluminum. The flux injector apparatus comprises a pressurized tank adapted to store and feed the flux under pressure. A feed mechanism operative to discharge a predetermined amount of flux to an outlet of the pressurized tank and a controller for monitoring and operating the apparatus. The feed mechanism includes a housing having an inner wall defining a cavity with an inlet and an outlet. A feed wheel is positioned within the cavity and operative to receive a predetermined amount of flux from the inlet, translate the flux within the cavity and discharge the predetermined amount of flux through the outlet of the pressurized tank.
In another embodiment, a method of distributing a predetermined amount of flux to an associated pool of molten aluminum is provided. The method includes providing a continuous amount flux to an inlet of a feed mechanism. A predetermined amount of flux is received by at least one notch of a feed wheel in the feed mechanism. The flux is translated to an outlet of the feed mechanism. Inert gas is mixed with the predetermined amount of flux and the flux and inert gas mixture is introduced into a pool of molten aluminum.
According to a further embodiment of the present disclosure, a flux injector apparatus for distributing flux to a pool of molten metal is provided. The assembly includes a feed mechanism within a pressurized tank. The tank is adapted to store and introduce flux to an inlet of the feed mechanism. The feed mechanism includes a feed wheel within a cavity of a housing having an inlet and an outlet. The feed wheel includes a plurality of notches in selective rotational alignment with the inlet and the outlet for receiving a predetermined amount of flux through the inlet and discharging the flux through the outlet. The inlet of the feed mechanism has an undercut portion at a leading edge to prevent blockage. The outlet of the feed mechanism is aligned with an outlet of the pressurized tank and adapted to be introduced to an associated pool of molten metal.
One advantage of the present disclosure is an assembly and method of use for a flux injector apparatus to provide a precise amount of flux to a pool of molten aluminum. Another advantage of the present disclosure is an assembly and method that safely stores and measures flux to prevent an overflow of flux provided to the pool of molten aluminum. The assembly also prevents flux overflow and environmental contamination. Yet another advantage of the present disclosure is a mechanism to maintain pressurized gas flow to the hollow shaft while isolating the pressurized tank.
It is to be understood that the detailed figures are for purposes of illustrating the exemplary embodiments only and are not intended to be limiting. Additionally, it will be appreciated that the drawings are not to scale and that portions of certain elements may be exaggerated for the purpose of clarity and ease of illustration.
With reference to
The pressurized tank is a generally sealed enclosure with cylindrical body 20 having an opening 22 closed via a secured cap 24 at a first end 26 and a second end 28 that is oppositely disposed from the first end 26. In one embodiment, the opening 22 is configured to receive flux and includes a screen to prevent foreign material or clumps of flux from entering the tank 14. The pressurized tank 14 is adapted to store an amount of flux under a controlled pressure. A controller 30 such as a programmable logic controller (PLC) based electric and gas control panel is provided in an enclosure 32. In one embodiment, the controller 30 is mounted to the structural base 12. However, the controller 30 can be provided at a location remote from the structural base 12.
The pressurized tank 14 can be provided with at least one sight window 34 on the cylindrical body 20 for visual verification of the internal operation of the assembly 10. More particularly, the sight window 34 allows a user to inspect the flow of flux therein and to identify properly working components within the tank 14. In one embodiment, the pressurized tank 14 is designed to operate at a threshold pressure of less than fifteen (15) pounds per square inch gauge (psig). In another embodiment the pressurized tank 14 is operated at a working pressure between two (2) psig and ten (10) psig. The pressurized tank 14 includes redundant pressure relief valves 36 to prevent an unwanted level of pressurization. A tank drain 38 is also provided for emptying or cleaning the assembly 10. In one embodiment, the tank is constructed with a powder coated material to prevent corrosion and clogging due to the interaction of flux and other chemicals.
With reference to
The storage tank 50 is positioned within the pressurized tank 14 adjacent the opening 22 at the first end 26 of the pressurized tank 14 such that additional flux can be provided through the opening 22. The cap 24 is provided at the opening 22 to provide a sealed fit to prevent moisture from accumulating within the tank 14 and to prevent excess flux and fumes associated with the flux to be released from within the storage tank 50. In one embodiment, the storage tank 50 includes a conical shaped base 52 that abuts an inner wall 54 of the tank 14. The storage tank 50 is defined by the area within the inner wall 54 between the first end 26 and the conical shaped base 52. The conical shaped base 52 is configured to allow flux to accumulate at a base aperture 56 that is in communication with the feed inlet 42 of the feeding mechanism 40. The storage tank 50 can include an equalization tube 55 in fluid communication with lower portion 57 of the pressurized tank 14 to allow pressure equalization while preventing unwanted flux transfer. In one embodiment, the storage tank 50 is adapted to contain approximately 100 pounds (45.36 kilograms) of flux.
The at least one sight window 34 allows a user to view the feed mechanism 40 as it operates within the pressurized tank 14. Additionally, hoses 16a and 16b are adapted to communicate between the isolation mechanism 18 and a gas/pneumatic controller (not shown). Hose 16a is a gas bypass line for inert gas flow wherein hose 16b is a pneumatic control supply line to actuate a valve in the isolation mechanism 18. The controller 30 is configured to control the level of pressure within the tank 14 and to identify and relay an alarm signal or audible sound to indicate an over pressurization condition of the tank 14. The over pressurization alarm signal can indicate the existence of shaft clogging within the system, downstream from the isolation mechanism 18, particularly in conduit 48.
The controller 30 is adapted to monitor and operate the flux injector assembly 10. The controller 30 can manipulate the feed mechanism 40, isolation mechanism 18 and adjust the level of pressure within the pressurized tank 14. The controller 30 manipulates the feed mechanism 40 to provide a predetermined amount of flux from the inlet 42 to the outlet 44 and will be more fully described herein. A first optic sensor 58 is provided adjacent the base aperture 56 to monitor the level of the flux in the storage tank 50. The optic sensor 58 sends a signal to the controller 30 that indicates the level of flux within the tank 50. Optionally, a second optic sensor 59 can be provided adjacent the feed outlet 44 of the feed mechanism 40 to communicate with the controller 30 to reflect that flux is being transferred through the feed outlet 44.
With reference to
The feed wheel 70 is positioned within the cavity 64 and is capable of being rotated in a direction R along a central rotational axis 82 by a rotor 80 in communication with a motor 90. (See
With reference to
With further reference to
In one embodiment the controller 30 is programmed to provide a threshold amount of flux to a pool of molten aluminum. The motor 90 rotates the feed wheel 70 at a controlled rotational rate such that a precise amount of flux is discharged from the outlet 44 and transferred through the collector 46 to the isolation mechanism 18. The rotations per minute of the feed wheel 70 are scalable by the controller 30 such that a change in rotational speed of the feed wheel 70 changes the amount of flux that is injected or discharged through the outlet 44. In one embodiment, the feed wheel 70 is provided with ten (10) notches 72 such that each notch 72 is adapted to hold one/tenth ( 1/10) gram of flux. Each full rotation of the feed wheel 70 would discharge one (1) gram of flux. Optionally, the volume of each notch 72 can be configured to include more or less flux. Further, any number of notches 72 can be located around the feed wheel 70. The controller 30 and feed mechanism 40 arrangement safely transfer an amount of flux that is less than or equal to a programmed or threshold amount as determined by the controller 30. Notably, as the notches 72 are rotated past the transfer aperture 67 of inlet 42, the amount of flux received in each notch 72 may be less than but not greater than the volume of each notch 72. This feature prevents the discharge of more flux than desired.
In one embodiment, the motor 90 includes a gear reducer such that one rotation of the rotor 80 is approximately equal to a partial rotation of the feed wheel 70. The partial rotation of the feed wheel 70 can be adapted to approximately equal the rotational distance for a single notch 72 holding flux to pass the feed outlet 44 and discharge flux from the single notch 72. The motor 90 can provide a signal to the controller to indicate every notch 72 that passes the feed outlet 44. Additionally, the motor 90 can be a step motor type with a fractional horsepower rating to drive or rotate the rotor 80 and the feed wheel 70 at a rotational rate as controlled by the controller 30.
In one embodiment, an inert gas such as argon or nitrogen is mixed with the predetermined amount of flux at the isolation mechanism 18. Alternatively, the inert gas can be mixed with the predetermined amount of flux within the pressurized tank 14 for example, at the collector 46. The isolation mechanism 18 is configured to communicate with a system of tubes (not shown) under pressure to introduce the flux/gas mixture into a pool of molten aluminum. Isolation mechanism 18 of the flux injector assembly 10 can be adapted to discharge flux as carried by the inert gas into a central hollow rotor (not shown) within the pool of aluminum. The hollow rotor is attached to an impeller such that rotation of the rotor distributes the flux into the molten aluminum through a plurality of apertures or fins within the impeller. This method efficiently degasses the molten aluminum such that hydrogen and other impurities are reduced from the molten aluminum. In one embodiment, this method causes an increase amount of hydrogen to rise to the top level of the molten aluminum where the hydrogen releases to the atmosphere or burns. The isolation mechanism 18 is easily detachable and attachable to the system of tubes and the hollow rotor such that the isolation mechanism 18 and control of pressure within the tank 14 are adapted to prevent molten material backflow from entering the pressurized hollow shaft (not shown) and connecting conduits, especially during the initial connection to the system of tubes.
According to yet another embodiment of the present disclosure, provided is a flux injector apparatus for distributing flux to a pool of molten metal. The flux material can include a mixture of magnesium chloride and potassium chloride. The flux is in a powdered or granular form having a grain size of 1-3 mm. The flux injector is controlled to discharge the flux at a rate between 2 grams per minute and 25 grams per minute. The flux is mixed with an inert gas such as argon at a flow rate between 20 standard cubic feet per hour (scfh) and 200 scfh.
The controller 30 is configured to modulate the pressure, meter the flux and monitor the amount of flux entering the injection system. The controller 30 can transmit an alarm signal or audible sound to identify if the first or second optic sensors 58, 59 have communicated to the controller 30 identifying that the flow of flux has stopped. The controller 30 can indicate the level of flux remaining within the pressurized tank 14 and includes gauges to sense and indicate the pressure within the tank 14 and alarms to identify a low or high pressure level. Notably, a high pressure level signal can indicate the existence of molten backflow or other clog existing within the system of tubes and central hollow rotor(not shown) that are in communication with the isolation mechanism 18. Additionally, it is beneficial to assemble the storage tank 50 with the feed mechanism 40 in a common pressurized tank 14 to allow for a metered and controlled distribution of flux along an interface that does not include a pressure differential. The metering of flux without a pressure differential interface reduces the need for sealed and pressurized transfer devices thereby decreasing cost and increasing consistency of operation of the flux injector assembly 10.
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US12/41209 | 6/7/2012 | WO | 00 | 11/18/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61494127 | Jun 2011 | US |
