Abstract
This invention provides an improved method and apparatus for controlling the flow of molten metal alloys and, in particular, to a method to finely control the delivery rate of liquid aluminum alloys and the liquid fraction of semi-solid aluminum alloys. The apparatus and method described herein provide for the pumping of liquid metal alloys in a precise and controlled manner. By controlling the heat flow through a section of the pump piston, the pump chamber, the porous liner of the pump chamber and the metal alloy charge, the present invention provides a means to deliver liquid metal alloys at high pressure through one or more exit ports.
Claims
1. A method to deliver a liquid metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the walls of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge.
2. The method of claim 1 wherein the solid annulus is maintained using a cooling channel in thermal contact with a section of the movable piston.
3. The method of claim 1 wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the charge to a port or a group of ports.
4. An apparatus to deliver a liquid metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the walls of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge.
5. The apparatus of claim 4 wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston.
6. The apparatus of claim 4 wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the charge to a port or a group of ports.
7. A method to deliver a liquid fraction of an metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the porous liner of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge.
8. The method of claim 7 wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston.
9. The method of claim 7 wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the liquid fraction of a charge to a port or a group of ports.
10. An apparatus to deliver a liquid fraction of an metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the porous liner of a piston chamber and a movable piston, the pressure tight seal composed of a solid annulus of the metal alloy charge.
11. The apparatus of claim 10 wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston.
12. The apparatus of claim 10 wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the liquid fraction of a charge to a port or a group of ports.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
[0019] FIG. 1 is a schematic of the first embodiment of the invention employing a employing a single piston and a single pressure seal; and
[0020] FIG. 2 is a schematic of the second embodiment of the invention employing a single piston, a single pressure seal and a porous chamber liner; and
[0021] FIG. 3 is a schematic of the third embodiment of the invention employing dual opposing pistons and two pressure seals.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention provides for a means of sealing the pressure within a piston chamber to deliver liquid metal alloys at high pressure through one or more exit ports or outlets. The present invention also provides for an apparatus for applying pressure to control the flow of such aluminum alloys through the controlled motion of one or more pistons, and for the use of this pressure to separate the liquid fraction of a charge from the solid fraction. The present invention is now discussed in more detail referring to the drawings that accompany the present application. In the accompanying drawings, like and/or corresponding elements are referred to by like reference characters.
[0023] Referring to FIG. 1, the first embodiment employing a single piston pump is described. The pump apparatus is comprised of a movable pump piston assembly 1 within a piston chamber 2 with an exit port assembly 3 affixed at the opposing end of the piston chamber from the piston. The piston assembly 1 is comprised of a piston face 1a which is mechanically linked and in physical and thermal contact with the piston bearing 1b. The piston bearing 1b is sized so as to provide a loose fit within the walls 2a of the piston chamber so as to allow for free translational motion of piston within the piston chamber walls. The piston bearing is affixed to a hollow cooling shaft 1c. Intermediate thermal insulation rings 1d may be positioned between the cooling shaft and the piston bearing to modulate heat flow from the piston bearing to the cooling shaft. The cooling shaft 1c is comprised of a co-axial cooling chamber 1e wherein coolant 4 (water, air or a water/air mixture) is pumped through the central conduit 1f and returned via the annular conduit 1g so as to provide active cooling to the piston bearing.
[0024] In further reference to FIG. 1, the piston chamber 2 is comprised of the piston chamber walls 2a, the piston chamber pressure vessel 2b enclosing and in mechanical contact with the piston chamber walls, and heating jackets 2c. The heating jackets may be comprised of induction heaters, resistance heaters or gas heaters. Enclosing the heating jackets 2c is thermal insulation 2d.
[0025] In yet further reference to FIG. 1, the pump apparatus comprises an exit port body 3 positioned at the opposing end of the piston chamber 2 from the movable piston assembly 1. The port body is comprised of a central fluid passage 3a to provide egress of the liquid portion of the metal alloy charge. The port body may be heated by port body heaters 3b to control the temperature of the port body so as to promote the melting or freezing of the metal charge within the central fluid passage. Removable filter materials 3c, commonly used in the processing of liquid aluminum alloys, may be inserted between the piston chamber walls 2a and the exit port 3.
[0026] In yet further reference to FIG. 1, the operation of the apparatus is as follows: [0027] the piston assembly 1 is withdrawn from the piston chamber 2; [0028] an metal alloy charge 5 is loaded into the piston chamber. This charge may be in solid form (as chips or turnings) or in liquid form; [0029] the piston assembly 1 is then re-inserted into the heated piston chamber 2 and the charge compacted; [0030] the exit port body 3 is maintained at a temperature below the solidus of the charge 5 so as to occlude the fluid passage and prevent premature leaking of the liquid charge; [0031] upon compaction of the liquid or semi-solid charge, liquid metal alloy will be forced into the annulus 5a between the piston chamber lining 2a and the lands of the piston bearing 1b, the lands of the piston bearing 1b so configured as to provide a series of two or more grooves 1h wetted by the liquid metal, which, upon solidification in contact with cooled piston bearing act to provide a pressure tight seal between the piston bearing and the piston chamber lining.
[0032] In final reference to FIG. 1, the piston assembly 1 is translated into the piston chamber 2 forcing liquid metal alloy charge 5 through the heated exit port 3 to provide a controlled flow of charge through the fluid passage under controlled pressure. The process above is then repeated upon re-charging of the pump apparatus to provide semi-continuous flow.
[0033] Referring to FIG. 2, the second embodiment employing a single piston and a porous piston chamber lining is described. The pump apparatus is comprised of a movable pump piston assembly 1 within a piston chamber lining 7, within a piston chamber 2 with an exit port assembly 3 affixed at the opposing end of the piston chamber from the piston. The piston assembly 1 is comprised of a piston face 1a which is mechanically linked and in physical and thermal contact with the piston bearing 1b. The piston bearing 1b is sized so as to provide a loose fit within the lining of the piston chamber 7 so as to allow for free translational motion of piston within the piston chamber lining. The piston bearing is affixed to a hollow cooling shaft 1c. Intermediate thermal insulation rings 1d may be positioned between the cooling shaft and the piston bearing to modulate heat flow from the piston bearing to the cooling shaft. The cooling shaft 1c is comprised of a co-axial cooling chamber 1e wherein coolant 4 (water, air or a water/air mixture) is pumped through the central conduit 1f and returned via the annular conduit 1g so as to provide active cooling to the piston bearing.
[0034] In further reference to FIG. 2, the porous piston chamber liner 7 is installed within chamber 2 in thermal and mechanical contact with the piston chamber walls 2a, with the piston chamber walls in mechanical contact with the pressure vessel 2b. The heating jackets 2c surround the pressure vessel. The heating jackets may be comprised of induction heaters, resistance heaters or gas heaters. Enclosing the heating jackets 2c is thermal insulation 2d.
[0035] In yet further reference to FIG. 2, the pump apparatus comprises an exit port body 3 positioned at the opposing end of the piston chamber from the movable piston assembly. The port body is comprised of a central fluid passage 3a to provide egress of the liquid fraction of the metal alloy charge. The port body may be heated by port body heaters 3b to control the temperature of the port body so as to promote the melting or freezing of the metal charge within the central fluid passage. Removable filter materials 3c, commonly used in the processing of liquid aluminum alloys, may be inserted between the piston chamber walls 2a and the exit port 3.
[0036] In yet further reference to FIG. 2, the operation of the apparatus is as follows: [0037] the piston assembly 1 is withdrawn from the piston chamber 2; [0038] an metal alloy charge 5 is loaded into the piston chamber. This charge may be in solid form (as chips or turnings) or in liquid form; [0039] the piston assembly 1 is then re-inserted into the heated piston chamber 2 and the charge compacted; [0040] the exit port body 3 is maintained at a temperature below the solidus of the charge 5 so as to occlude the fluid passage and prevent premature leaking of the liquid charge; [0041] upon compaction of the liquid or semi-solid charge, liquid metal alloy will be forced into the annulus 5a between the piston chamber lining 2a and the lands of the piston bearing 1b, the lands of the piston bearing 1b so configured as to provide a series of two or more grooves 1h wetted by the liquid metal, which, upon solidification in contact with cooled piston bearing act to provide a pressure tight seal between the piston bearing and the porous piston chamber lining 7.
[0042] In final reference to FIG. 2, the piston assembly 1 is translated into the piston chamber 2 forcing the liquid portion of the metal alloy charge 5 through the porous liner 7 and into the heated exit port 3 to provide a controlled flow of the liquid fraction of the charge through the fluid passage. With the liquid fraction of the charge now being ejected from the exit port, the solid fraction of the charge can be further heated, permitting the subsequent liquid fractions of the (now hotter) charge to be forced through the porous liner and the exit port. The process above is then repeated upon re-charging of the pump apparatus to provide semi-continuous flow.
[0043] Referring to FIG. 3, the third embodiment employing a dual piston pump is described. The pump apparatus is comprised of two movable pump pistons, pump assembly 1 and pump assembly 6, within a piston chamber 2 with an exit port assembly 3 positioned in the piston chamber between the piston faces 1a and 6a. The piston assembly 1 is comprised of a piston face 1a which is mechanically linked and in physical and thermal contact with the piston bearing 1b. The piston bearing 1b is sized so as to provide a loose fit within the walls 2a of the piston chamber so as to allow for free translational motion of piston within the piston chamber lining. The piston bearing is affixed to a hollow cooling shaft 1c. Intermediate thermal insulation rings 1d may be positioned between the cooling shaft and the piston bearing to modulate heat flow from the piston bearing to the cooling shaft. The cooling shaft 1c is comprised of a co-axial cooling chamber 1e wherein coolant 4 (water, air or a water/air mixture) is pumped through the central conduit 1f and returned via the annular conduit 1g so as to provide active cooling to the piston bearing.
[0044] The piston assembly 6 is comprised of a piston face 6a which is mechanically linked and in physical and thermal contact with the piston bearing 6b. The piston bearing 6b is sized so as to provide a loose fit within the walls 2a of the piston chamber so as to allow for free translational motion of the piston within the piston chamber lining. The piston bearing is affixed to a hollow cooling shaft 6c. Intermediate thermal insulation disks 6d may be positioned between the cooling shaft and the piston bearing to modulate heat flow. The cooling shaft 6c is comprised of a co-axial cooling chamber 1e wherein coolant 4 (water, air or a water/air mixture) is pumped through the central conduit 6f and returned via the annular conduit 6g so as to provide active cooling to the piston bearing.
[0045] In further reference to FIG. 3, the piston chamber 2 is comprised of the piston chamber walls 2a, the piston chamber pressure vessel 2b and heating jackets 2c. The heating jackets may be comprised of induction heaters, resistance heaters or gas heaters. Enclosing the heating jackets 2c is thermal insulation 2d.
[0046] In yet further reference to FIG. 3, the pump apparatus comprises an exit port body 3 positioned between the opposing pistons in the piston chamber. The port body is comprised of a central fluid passage 3a to provide egress of the liquid or semi-solid metal alloy charge. The port body may be heated by port body heaters 3b to control the temperature of the port body so as to promote the melting or freezing of the metal charge within the central fluid passage. Removable filter materials 3c, commonly used in the processing of liquid metal alloys, may be inserted between the piston chamber lining 2a and the exit port 3.
[0047] In yet further reference to FIG. 3, the operation of the apparatus is as follows: [0048] the piston assembly 1 or 6 is withdrawn from the piston chamber 2 and; [0049] an metal alloy charge 5 is loaded into the piston chamber. This charge may be in solid form (as chips or turnings) or in liquid form; [0050] the piston assembly 1 or 6 is then re-inserted into the heated piston chamber 2 and the charge compacted; [0051] the exit port body 3 is maintained at a temperature below the solidus of the charge 5 so as to occlude the fluid passage and prevent premature leaking of the liquid charge; [0052] upon compaction of the liquid or semi-solid charge, liquid metal alloy will be forced into the annulus 5a between the piston chamber lining 2a and the lands of the piston bearing 1b, the lands of the piston bearing 1b so configured as to provide a series of two or more grooves 1h wetted by the liquid metal, which, upon solidification in contact with cooled piston bearing, key into the piston bearing in intimate physical and thermal contact so as to create a pressure tight seal between the piston bearing and the piston chamber walls. Liquid metal alloy will also be forced into the annulus 5b between the piston chamber walls 2a and the lands of the piston bearing 6b, the lands of the piston bearing 6b so configured as to provide a series of two or more grooves 6h wetted by the liquid metal, which, upon solidification in contact with cooled piston bearing, key into the piston bearing in intimate physical and thermal contact so as to create a pressure tight seal between the piston bearing and the piston chamber walls.
[0053] In final reference to FIG. 3, piston assembly 1 or piston assembly 6 is extended into the piston chamber 2 forcing liquid metal alloy charge 5 through the heated exit port 3 to provide a controlled flow of charge through the fluid passage under controlled pressure. The process above is then repeated upon re-charging of the pump apparatus to provide semi-continuous flow.
[0054] As such, an invention has been disclosed in terms of preferred embodiments thereof which fulfills each and every one of the objects of the present invention as set forth above and provides a new and improved method and apparatus to deliver liquid metal alloys in finely controlled measured amounts through one or more ports.
[0055] Of course, various changes, modifications and alterations from the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention only be limited by the terms of the appended claims.
[0056] It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Such modifications are to be considered as included within the following claims unless the claims, by their language, expressly state otherwise. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
