Pouring control device

A device for control of the pouring process in molds, wherein molten metal is adapted to be tapped from a vessel (e.g. a pouring furnace, a ladle or a tundish) provided with a stopper or other flow-control valve means. Between the vessel and the mold at least one transmitter coil and at least one receiver coil are positioned for measuring the degree of filling of the mold, suitably in a pouring cup. The output signal from the receiver coil is supplied to a signal processing device for control of the flow-control valve means.

TECHNICAL FIELD 
The present invention relates to a device for control of the pouring 
process in casting molds, wherein a molten metal is adapted to be tapped 
from a pouring furnace, a ladle or a tundish, provided with a stopper or 
other valve member. 
DISCUSSION OF PRIOR ART 
In this kind of pouring process, it is desired to control the pouring 
operation such that the volume of molten metal poured is controlled in a 
precise manner. Different level measuring devices are available on the 
market, but these are either too expensive, too inaccurate or too 
unreliable in operation, or else they require the use of a special pouring 
cup. In addition, from an environmental aspect, the use of such known 
devices may also cause problems. 
SUMMARY OF THE INVENTION 
A device according to the invention aims to provide a solution to the 
problems mentioned above and other related problems and is characterized 
in that between the furnace and the casting mold there is arranged at 
least one transmitter coil and at least one receiver coil for measuring 
the degree of filling of the mold, suitably in a pouring cup, whereby the 
output signal from the receiver coil is supplied to a signal processing 
device for control of a flow-control valve means. 
With a device as described above, the quantity of molten metal supplied to 
a mold, a pouring cup or a casting ball can be controlled in an efficient 
way. It is also possible to arrange for the pouring to be carried out in a 
manner which is quite excellent from the point of view of environmental 
considerations. As an example of a measuring device which can be used in 
connection with the invention can be mentioned the device disclosed in 
Linder's U.S. Pat. No. 4,138,888 which uses a transmitter coil and a 
receiver coil, albeit in an application different from that described 
herein.

DESCRIPTION OF PREFERRED EMBODIMENT 
The mold is shown at 1 and may consist of a casting ball, a mold flask or 
any other casting mold intended for intermittent pouring, and it is 
desired to obtain an accurately adapted volume of molten metal by using 
this device. Molten metal is tapped from a vessel 2 (e.g. a pouring 
furnace, a tundish or a ladle) provided with flow-control valve means 4 
(shown as a stopper rod) for closing a bottom tap hole 3. Alternatively in 
place of a stopper some other form of valve member, such as a sliding 
valve (not shown), can be used. The mold 1 is provided with an extended 
portion, a so-called pouring cup 5. A transmitter coil 6 and a receiver 
coil 7 are located on either side of the stream of melt 8 leaving the tap 
hole 3 between the pouring furnace 2 and the mold 1. The coils 6, 7 form a 
measuring device but an alternative measuring device of electromagnetic 
type can also be used. The stopper rod 4, for closing the tap hole 3, is 
suitably moved by means of a hydraulic cylinder 9, which receives 
pressurized hydraulic medium from a container 10, the supply being 
controlled via a valve member 11. 
From the transmitter coil 6, an electromagnetic field is emitted, which is 
received by the receiver coil 7. The output signal from the transmitter 
coil 6 and the reception of the signal by the coil 7 are processed by an 
indicator device 12. When the melt reaches up to a certain level in the 
pouring cup 5, which is suitably pre-settable, the indicator device 12 
receives a signal from the coil 7, and an impulse for adjustment of the 
position of the stopper rod 4 can be obtained. The indicator device 12 is 
connected to a computer 13, the output signal of which, as well as a 
signal setting the actual position of the stopper rod 4, are supplied to a 
summation device 14. The output signal from the summation device 14 is 
supplied to the valve member 11 for adjustment of the hydraulic cylinder 9 
and hence for adjustment of the position of the stopper rod 4. Thus, when 
the melt has reached up to a certain level in the pouring cup 5, the 
hydraulic cylinder 9 receives a signal, and the stopper rod 4 is lowered 
to close the tap hole 3. This regulation can become very exact and is 
favorable from an environmental point of view. The device illustrated 
allows the poured weight and/or the pouring rate to be changed within wide 
limits without any change of the parameters set. 
Numeral 16 designates a device for switching to manual control from 
automatic control which is effected via a line 17. 
The reason for the changed signal transmitted by the coil 7 in the case of 
a rising melt level in the pouring cup 5 is that the reluctance for the 
electromagnetic flux between the transmitter coil 6 and the receiver coil 
7 is changed as melt builds up in the flow path between the transmitter 
coil 6 and the receiver coil 7. It would, of course, be possible to use 
several transmitter and receiver coils and these do not necessarily have 
to be located in close proximity to the stream of melt 8 but can be 
located at some distance away therefrom. 
The transmitter and receiver coils 6, 7 may be located in a plane 
perpendicular to the stream of melt 8, or in a plane at an acute angle to 
the stream of melt 8. The pouring cup 5 may be conical, cup-shaped, or 
otherwise enlarged in relation to the subsequent filling tube in the mold 
1. 
The transmitter and receiver coils 6, 7 may be located so close to the 
pouring cup 5 that the flux between these coils is influenced at that 
level of the melt at which tapping is to be regulated and stopped. By a 
correct choice of the position of the plane through the coils 6, 7, a high 
degree of sensitivity the measurement signals can be obtained. 
The transmitter coil 6 is, in the case illustrated, supplied with 
alternating current with a frequency adapted to the particular purpose. 
The coils 6, 7 are located immediately above the mold 1, but are directed 
such that the reluctance in the flow path therebetween is influenced in 
the case of a change in the level of the pouring cup 5. 
FIG. 2 shows how, in a typical case the flow rate will rise to a maximum 
and will then tail off in a controlled fashion as the required volume of 
melt is attained. 
The mold filling control device described can be used with advantage with 
the channel induction furnace marketed by ASEA AB of V /aster.ang.s, 
Sweden, under the trade Mark PRESSPOUR. 
The device illustrated in FIG. 1 can be varied in many ways within the 
spirit and scope of the following claims.