US5170838A — Program-controlled feeding of molten metal into t…

Claim 1

Independent Claim 182 words

Process for feeding molten metal into dies, internally insulated in the upper region thereof, of an automatic continuous casting plant having a runner system, which comprises: providing a plurality of dies and a distributor trough communicating with the dies and runner system; feeding said dies with molten metal at the same metal level; providing an inner ring of said dies and maintaining a gas cushion that prevents direct contact of the dies with the molten metal in the region situated below said inner ring; injecting oil into the region of the inner ring; conducting said gas cushion via a joint main having distribution lines which conducts said gas cushion; and computing the relative pressure between a desired value computed by a program as a function of the metal level [(H 2 )] measured via a level probe and an actual value measured in the main by means of a measuring transducer serving for program-controlled regulation and monitoring, and fulfilling a regulator function by means of a processor through the output of a signal for an actuator of a joint pressure control valve.

Claim 2

Dependent Claim 182 words

Process for feeding molten metal into dies, internally insulated in the upper region thereof, of an automatic continuous casting plant having a runner system, which comprises: providing a plurality of dies and a distributor trough communicating with the dies and runner system; feeding said dies with molten metal at the same metal level; providing an inner ring of said dies and maintaining a gas cushion that prevents direct contact of the dies with the molten metal in the region situated below said inner ring; injecting oil into the region of the inner ring; conducting said gas cushion via a joint main having distribution lines which conducts said gas cushion; and computing the relative pressure between a desired value computed by a program as a function of the metal level [(H 2 )] measured via a level probe and an actual value measured in the main by means of a measuring transducer serving for program-controlled regulation and monitoring, and fulfilling a regulator function by means of a processor through the output of a signal for an actuator of a joint pressure control valve.

Claim 3

Dependent Claim 14 words

Process according to claim 1 wherein said gas cushion is air or inert gas.

Claim 4

Dependent Claim 24 words

Process according to claim 1 including the step of providing that said inner ring of said dies includes insulation and includes a bevel portion.

Claim 5

Dependent Claim 12 words

Process according to claim 1 wherein the variable external pressure is compensated.

Claim 6

Dependent Claim 29 words

Process according to claim 1 wherein said process obtains castings and including the step of withdrawing a die frame and stopping bases beneath the castings during the casting operation.

Claim 7

Dependent Claim 62 words

Process according to claim 5 wherein at the start of casting and without molten metal, the gas flow (V) per die reaches a first higher value (V A ) and, with flowing metal, the withdrawal of the die frame with the stopping bases is triggered shortly after the undershooting of a second, lower value (V 1 ) of the gas flow (V).

Claim 8

Dependent Claim 51 words

Process according to claim 6 wherein the first value (V A ) is about 12-15 Nl/min in the case of a set pressure of about 45 mbar, the second value (V 1 ) is about 8-10 Nl/min, and the delay after the second value has been reached is about 5 seconds.

Claim 9

Dependent Claim 100 words

Process according to claim 3 wherein the minimum and the maximum pressure in the gas cushion is set as a function of the metallostatic pressure, the minimum pressure being the function of the density of the molten metal, the acceleration due to gravity, the metal level, the interface strain of the molten metal in the region of the insulation and the surface tension of the molten metal in the region of the gas cushion, and the maximum pressure is a function of the density of the molten metal, the acceleration due to gravity and the depth of the bevel portion.

Claim 10

Dependent Claim 20 words

Process according to claim 1 wherein the same amount of oil is supplied per unit of time to all dies.

Claim 11

Dependent Claim 19 words

Process according to claim 9 wherein the oil is injected in pulses into the region of the gas cushion.

Claim 12

Dependent Claim 17 words

Process according to claim 1 including the step of automating the start-up and end of said feeding.

Claim 13

Dependent Claim 161 words

Device for feeding molten metal into dies, internally insulated at the upper region thereof, of an automatic continuous casting plant, which comprises: a runner system; a plurality of dies downstream of the runner system; a distributor trough feeding said dies communicating with said runner system with molten metal at the same metal level; an inner ring of said dies; a gas cushion that prevents direct contact of the dies with the molten metal maintained in the region situated below said inner ring; a main having a plant side and a computer side, said main being for the gas supply and having on the plant side a servo delivery valve and a measuring transducer, said measuring transducer having actual pressure controlled variables, and having on the computer side a processor which compares the actual pressure controlled variables of the measuring transducer and a controlled variable of a desired pressure, and triggers a manipulated variable for the actuator of the pressure control valve.

Claim 14

Dependent Claim 161 words

Device for feeding molten metal into dies, internally insulated at the upper region thereof, of an automatic continuous casting plant, which comprises: a runner system; a plurality of dies downstream of the runner system; a distributor trough feeding said dies communicating with said runner system with molten metal at the same metal level; an inner ring of said dies; a gas cushion that prevents direct contact of the dies with the molten metal maintained in the region situated below said inner ring; a main having a plant side and a computer side, said main being for the gas supply and having on the plant side a servo delivery valve and a measuring transducer, said measuring transducer having actual pressure controlled variables, and having on the computer side a processor which compares the actual pressure controlled variables of the measuring transducer and a controlled variable of a desired pressure, and triggers a manipulated variable for the actuator of the pressure control valve.

Claim 15

Dependent Claim 21 words

Device according to claim 12 including connecting lines leading exclusively directly to the dies, said lines branching off from the main.

Claim 16

Dependent Claim 23 words

Device according to claim 13 wherein the sum of the cross-section of all the connecting lines is below the cross-section of the main.

Claim 17

Dependent Claim 27 words

Device according to claim 14 wherein the sum of the cross-section of all the connecting lines is below the cross-section of the main by at least 20%.

Claim 18

Dependent Claim 27 words

Device according to claim 12 wherein said inner ring is an upper insulating ring of the dies, said insulating ring having an undercut on the underside thereof.

Claim 19

Dependent Claim 21 words

Device according to claim 16 wherein said undercut comprises a bevel with a depth (H 2 ) of about 10 mm.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-12-15	1996-06-15	1996-12-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-12-15	2000-06-15	2000-12-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-12-15	2004-06-15	2004-12-15	$7700.00	Window Closed / Lapsed

Program-controlled feeding of molten metal into the dies of an automatic continuous casting plant

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