# US 9,434,000 B2 · System and method of forming a solid casting > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,434,000 B2 - Document ID: US9434000B2 - Status: Granted - Kind: B2 - Application number: 14/515,469 - Filed: 2014-10-15 - Published: 2015-04-16 - Granted: 2016-09-06 - Earliest claimed: 2013-10-15 - Assignees: Retech Systems LLC - Applicants: Retech Systems LLC - Inventors: Tony Tesoriere; Robin Lampson - Web page: https://patentgrep.com/patent/US9434000B2 ## CPC - B22D 7/00: Casting ingots, {e.g. from ferrous metals}(equipment for conveying molten metal B22D35/00) - B22D 7/06: Ingot moulds or their manufacture - B22D 7/064: {Cooling the ingot moulds} - B22D 27/06: Heating the top discard of ingots (hot tops for ingot moulds B22D7/10) - B22D 37/00: Controlling or regulating the pouring of molten metal from a casting melt-holding vessel ({B22D11/18,} B22D39/00, B22D41/00 take precedence) - B22D 41/015: with external heating, i.e. the heat source not being a part of the ladle - B22D 46/00: Controlling, supervising, not restricted to casting covered by a single main group, e.g. for safety reasons (controlling or regulating in general G05) - B22D: CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES (shaping of plastics or substances in a plastic state B29C; metallurgical processing, selection of substances to be added to metal C21, C22) ## Abstract A method and a system for forming a solid casting. A material is fed into a mold having a retractable bottom. A first portion of the material at a first, lower position within the mold is allowed to solidify to thereby form a portion of the casting. The retractable bottom is withdrawn downwards at a withdrawal rate. A second portion of the material at a second, upper position within the mold is maintained in a liquid state by application of heat thereto, using a plasma arc generated by a plasma arc torch. A voltage of the plasma arc is measured, and the withdrawal rate of the retractable bottom is controlled based on the voltage of the plasma arc. ## Claims ### Claim 1 A method of forming a solid casting, comprising: feeding a material into a mold, the mold comprising a retractable bottom; allowing a first portion of the material at a first, lower position within the mold to solidify, to thereby form a portion of the casting; withdrawing the retractable bottom downwards at a withdrawal rate; maintaining a second portion of the material at a second, upper position within the mold in a liquid state by applying heat to the second portion of the material using a plasma arc generated by a plasma arc torch; measuring a voltage of the plasma arc; and controlling the withdrawal rate of the retractable bottom based on the voltage of the plasma arc. ### Claim 2 (depends on 1) The method of claim 1, wherein the measured voltage is a voltage between a power supply of the plasma arc torch and a ground. ### Claim 3 (depends on 2) The method of claim 2, wherein the ground is measured at the casting. ### Claim 4 (depends on 1) The method of claim 1, wherein the voltage is indicative of a distance between the plasma arc torch and a top surface of the second portion of the material. ### Claim 5 (depends on 4) The method of claim 4, wherein the voltage is directly proportional to the distance between the plasma arc torch and the top surface of the second portion of the material. ### Claim 6 (depends on 1) The method of claim 1, wherein controlling the withdrawal rate comprises at least one member of the group consisting of: processing a signal of the voltage, filtering the voltage signal, proportional control based on the voltage signal, integral control based on the voltage signal, derivative control based on the voltage signal, and combinations thereof. ### Claim 7 (depends on 1) The method of claim 1, wherein the mold is a crucible and the casting is an ingot. ### Claim 8 (depends on 1) The method of claim 1, further comprising: forming a portion of the casting by controlling the step of forming the portion of the casting based on the voltage of the plasma arc. ### Claim 9 (depends on 8) The method of claim 8, wherein controlling the step of forming the portion of the casting comprises at least one member of the group consisting of: processing a signal of the voltage, filtering the voltage signal, proportional control based on the voltage signal, integral control based on the voltage signal, derivative control based on the voltage signal, and combinations thereof. ### Claim 10 (depends on 1) The method of claim 1, wherein the controlling step comprises controlling at least one of: the feeding, the allowing to solidify, the withdrawing, and the maintaining. ### Claim 11 (depends on 10) The method of claim 10, wherein the controlling step comprises controlling a rate of the at least one of: the feeding, the allowing to solidify, the withdrawing, and the maintaining. ### Claim 12 (depends on 1) The method of claim 1, wherein the feeding step comprises: providing the material into a hearth; melting the material that has been fed into the hearth; and pouring the material that has been melted from the hearth into the mold. ### Claim 13 (depends on 12) The method of claim 12, wherein the controlling step comprises controlling at least one of: the feeding, the melting, the pouring, the allowing to solidify, the withdrawing, and the maintaining. ### Claim 14 (depends on 13) The method of claim 13, wherein the controlling step comprises controlling a rate of the at least one of: the feeding, the melting, the pouring, the allowing to solidify, the withdrawing, and the maintaining. ### Claim 15 (depends on 1) The method of claim 1, wherein withdrawing the retractable bottom downwards comprises pulling downwards with a dovetail puller. ### Claim 16 A solid casting forming system, comprising: a mold comprising a retractable bottom configured to be withdrawn downwards, the mold being configured for a material to be introduced therein, and for a first portion of the material at a first, lower position within the mold to solidify, to thereby form a portion of the casting; the retractable bottom having a dovetail puller configured to occupy a portion of the lower position in which the casting starts formation; a plasma arc torch configured and positioned relative to mold to generate a plasma arc and thereby apply heat to a second portion of the material at a second, upper position within the mold to thereby maintain the second portion of the material in a liquid state; and a controller configured to measure a voltage of the plasma arc and to control the forming the portion of the casting based on the voltage of the plasma arc. ### Claim 17 (depends on 16) The system of claim 16, wherein the measured voltage is a voltage between a power supply of the plasma arc torch and a ground. ### Claim 18 (depends on 17) The system of claim 17, wherein the controller is further configured to measure the ground at the casting. ### Claim 19 (depends on 16) The system of claim 16, wherein the measured voltage is indicative of a distance between the plasma arc torch and a top surface of the second portion of the material. ### Claim 20 (depends on 19) The system of claim 19, wherein the measured voltage is directly proportional to the distance between the plasma arc torch and the top surface of the second portion of the material. ### Claim 21 (depends on 16) The system of claim 16, wherein the mold is a crucible and the casting is an ingot.