Metallurgical apparatus – Means for melting or vaporizing metal or treating liquefied... – With means to discharge molten material
Patent
1982-12-23
1985-02-12
Rutledge, L. Dewayne
Metallurgical apparatus
Means for melting or vaporizing metal or treating liquefied...
With means to discharge molten material
266236, 222595, 222606, 222607, 164337, B22D 3900
Patent
active
044986610
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to metallurgy, and more particularly, to means for teeming molten metal into various kinds of moulds.
The invention is applicable to machines for continuous casting of metal into molds. It may also find extensive use in non-ferrous metallurgy.
2. Description of the Prior Art
In practice, wide use is made of metal teeming means (or ladle) which comprise a teeming chamber connected with refractory-lined sleeves for discharging molten metal into moulds and provided with a system for regulating the level of metal therein. The system in question includes a level-sensing means installed in the mould and connected to electromagnetic means for regulating the flow rate at which the molten metal is discharged from the teeming chamber.
Such construction of the metal-level control system is disadvantageous in that the level-sensing means are directly exposed to the action of molten metal. This in turn renders the control system unreliable in operation and leads to erroneous measurements in the level of metal. Electromagnetic flow gauges are complicated in construction and unreliable in operation under high-temperature conditions, and require substantial power inputs and operational costs.
From the above it follows that the prior-art metal teeming means are complicated in construction and the level control devices incorporated therein are insufficiently reliable in operation.
The error in gauging the level of metal may be as high as 20 percent and more, which brings about overfilling of some moulds and underfilling of others and, in the final count, results in a high degree of defective products and frequent faults in the operation of equipment.
There is also known means for teeming steel into, and regulating its level in the mould of a continuous casting machine. The means in question comprises a stoppered ladle having an actuator associated with a Laser-operated means for gauging the level of metal in the mould. Needless to say that such a construction is rather complicated and expensive due to the use of the Laser technique and optical instrumentation, which require that strictly stable operating conditions be provided in a steelmaking shop. This is an extremely difficult task to perform. Thus it should be mentioned that because of insufficiently reliable operation of the metal gauging means, the rate of errors in gauging the level of metal in the mould increases to bring about faulty operation of the metal-level control means. A higher amount of errors in adjusting the level of metal in the mould is caused by a time delay in cooperation between the metal-level gauging system and the actuator of the ladle stoppered mechanism. This also may result in the overfilling of the mould and, consequently, in damage to the equipment.
SUMMARY OF THE INVENTION
What is desired is a means for teeming molten metal into moulds of such a construction that will be simple and effective enough to ensure reliable and self-regulating adjustment of the metal level in the mould.
Thus the invention provides a teeming ladle which comprises a body having at least one tapping hole formed therein, according to the invention, a sleeve is arranged around each tapping hole substantially coaxially therewith and having one of its ends tightly connected with the ladle bottom, the other end thereof being immersed in the melt during casting; the sleeve having its diameter larger so many times than that of the tapping hole that after immersing the sleeve in the melt, a space is left in the sleeve interior filled with a gaseous medium under a pressure ranging from 0.02 to 1.0 times the pressure under which the melt is discharged from the ladle.
Such ladle construction permits an overpressure of gas to be created inside the sleeve during its immersion in the melt. This pressure produced under the head of metal disposed outside the sleeve acts as the gas medium present inside the latter. The head of metal and, consequently, the pressure of gas under the tapping hole is
REFERENCES:
patent: 3648761 (1972-03-01), Speith et al.
patent: 4222506 (1980-09-01), Sakashita et al.
patent: 4270595 (1981-06-01), Coward
McDowell Robert L.
Rutledge L. Dewayne
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