Metallurgical apparatus – With control means responsive to sensed condition
Reexamination Certificate
2001-09-05
2003-04-29
Andrews, Melvyn (Department: 1742)
Metallurgical apparatus
With control means responsive to sensed condition
C266S080000, C266S205000, C266S227000, C266S275000
Reexamination Certificate
active
06555050
ABSTRACT:
BACKGROUND OF THE INVENTION
To recover entrapped metal from drosses formed on melting and holding furnaces, the dross is placed in a reaction vessel and an exothermic flux is added to the dross. The dross is frequently agitated to promote coalescence of metal droplets therein. A molten metal pool forms in the bottom of the reaction vessel as the droplets coalesce. The molten metal pool is removed by draining through a bottom port. The demetallized or spent dross is then removed from the reaction vessel.
One preferred apparatus for recovering metal employing such a method is described in U.S. patent application Ser No. 09/654,314, now U.S. Pat. No. 6,464,929 for which one of the present inventors is the inventor. While the apparatus of the '314 application can greatly facilitate recovery of metal from drosses, the apparatus has some limitations.
The apparatus of the '314 application employs a motor to drive an impeller to agitate the dross while it is held in the reaction vessel. This apparatus, in some embodiments, has a motor which is raised and lowered by moving a motor arm to which the motor is mounted. Employing such a structure to position the motor can limit the degree of control over vertical position of the motor and the impeller, and can result in gyrations of the impeller when it encounters irregularities in the dross. These gyrations can result in damage of the impeller and/or the reaction vessel.
In some preferred embodiments, the apparatus of the '314 application has a protective shield or hood which is mounted above the impeller. Frequently, the shield is positioned such that the impeller enters the dross before such time as the shield is in place, allowing fumes generated in the reaction vessel to escape. Furthermore, the design of the shields of the '314application is such that they tend to a safety hazard as they are moved into position.
Another limitation is that the system of the '314 application is designed to be operated manually, and thus depends on the skill of the operator as well the operator's willingness to take the extra steps necessary to recover metal from the dross.
Thus, there is a need for a dross processing system which overcomes the problems discussed above.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a dross reclaiming system which employs a reaction vessel covered by a hood for containment of fumes where a gravity seal is employed to maintain the hood in place on the reaction vessel.
It is another object of the invention to stabilize an impeller employed to agitate the dross against reaction forces resulting from the inhomogeneous nature of the dross.
It is a further object of the invention to provide cyclic reversing motion to the impeller to enhance separation of the metal from the dross while in the reaction vessel.
It is still a further object of the invention to provide a hood that can be swung away from the reaction vessel so as to provide an open position which enhances accessability to the reaction vessel for loading and cleaning.
It is a further object of the invention to provide a dross processing system which includes a swingable hood in combination with an impeller immobilizing mechanism to immobilize the impeller when the dross processing system is in the open position.
It is a further object of the invention to provide a dross possessing system where the position of the impeller in the reaction vessel can be varied to operate the impeller at selected depths in the dross to enhance the rate of metal separation from the dross.
It is yet another object to provide a dross processing system wherein the motions of the impeller can be programmed so as to better match the characteristics of the dross being treated.
It is another object of the invention to provide a tool for inserting a plug in a dross processing vessel when the reaction vessel is hot.
SUMMARY OF THE INVENTION
The present invention is an improved dross processing system of the type which is positionable and can be placed so as to be in close proximity with respect to a melt furnace from which the dross is to be removed. The dross processing system for which the improvement is intended has a substantially vertical support which can be positioned near the melt furnace. A reaction vessel is provided for containing the dross during the recovery process. The reaction vessel has a reaction vessel upper rim and a bottom terminating in a drain port. The reaction vessel is affixed to a reaction vessel support which in turn is pivotably mounted with respect to the substantially vertical support. Preferably, the reaction vessel is mounted to reside entirely below the reaction vessel support. The dross processing system is also provided with means for pivoting the reaction vessel between a horizontal position, where the upper rim is substantially horizontal, and a dump position, where the dross residing in the vessel is eliminated by the force of gravity.
The system to which the present improvement is applicable also has a motor mounted on a motor support arm which attaches to the substantially vertical support. The motor has a drive shaft terminating in a drive shaft free end, and can be moved between a raised motor position and one or more lowered motor positions. An impeller, having an impeller axis, attaches to the free end of the drive shaft such that, when the motor is in the raised motor position and is aligned with the reaction vessel, the impeller resides above the upper rim of the reaction vessel, and when the motor is in each of the at least one lowered motor positions and aligned with the reaction vessel, the impeller resides below the upper rim of the reaction vessel.
One aspect of the improvement of the present invention resides in providing a motor support carriage, to which the motor is mounted, and a carriage guide which attaches to the motor support arm. The carriage guide engages the motor support carriage to limit the motion of the motor so as to direct the motor along a substantially vertical path as it moves between the raised motor position and the at least one lowered motor position. The combination of the motor support carriage and the carriage guide acts to stabilize the motor, and the impeller which is mounted thereto.
Means for raising and lowering the motor support carriage relative to the motor support arm are provided, which act to move the motor and the motor support carriage between the raised motor position and each of the at least one lowered motor positions. Such means can be provided by any of the various mechanisms known in the art for raising and lowering an element of a structure. One preferred means for raising and lowering the motor support carriage is a linear actuator connected at one end to the motor support arm and at the other to the motor support carriage, which provides a means for raising and lowering the motor carriage which is simple in structure and compact. The use of the means for raising and lowering the motor support carriage relative to the motor support arm rather than moving the motor support arm to adjust the vertical position of the motor provides increased stability and positional control for the motor and the impeller.
Preferably, the carriage guide is configured not only to limit translation of the motor carriage along a substantially vertical path, but also to provide resistance to torques imparted by the action of the impeller as it agitates the dross retained in the reaction vessel. Such resistance to torques can be obtained by providing at least two stabilizing tracks, each of which slidably engages a track guide to prevent any wobbling of the motor as the impeller agitates the dross. In one preferred embodiment, the stabilizing tracks are provided by rods affixed to the motor support carriage, and the track guides are passages in the motor support arm configured to slidably engage the rods. Preferably, the stabilizing tracks and track guides are evenly spaced about the impeller axis.
While the range of motion of the motor is typically limited by the means f
Becher Earl J.
Groteke Daniel E.
Judkins Joseph A.
Judkins Timothy J.
Andrews Melvyn
Q. C. Designs, Inc.
Semprebon Jeffrey E.
Weins Michael J.
LandOfFree
Dross processing system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dross processing system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dross processing system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3053533