Pumping liquid metals

Liquid metals are centrifugally pumped from a static container without the necessity for employing a mechanical impeller. A powerful rotating magnetic field surrounding the static container causes the metal to be rotated vigorously and the velocity head so created is converted in a volute shaped head into vertical motion to the desired delivery point.

FIELD OF INVENTION 
The present invention relates to the elevating of liquid metals. 
BACKGROUND TO THE INVENTION 
In the processing of liquid metals, it often is necessary to elevate the 
liquid metal from one location to another. Such elevation is 
conventionally carried out by linear induction machines or mechanical 
impeller pumps. 
Such linear induction systems employ open troughs which are subject to 
oxidation as well as permitting a head of only about one meter. The liquid 
metal is not pressurized and hence transport stops immediately outside the 
magnetic zone. 
Circular linear motors have been employed to elevate liquid metals in tubes 
with the limitation that the velocity can be induced only in a limited 
outside peripheral area of the tube, causing a reverse flow down the 
center. In addition, the velocity heads created are very low. 
SUMMARY OF INVENTION 
In accordance with the present invention, a novel method of elevating a 
liquid metal from an enclosed container is provided which overcomes the 
prior art problems noted above, by eliminating exposure of the liquid 
metal to atmosphere eliminating the need for seals and mechanical devices 
and by significantly increasing the head attainable. 
In the present invention, a rotating electromagnetic field is provided 
surrounding the container in which the liquid metal, such as molten iron 
or steel, is enclosed. Such rotating electromagnetic field is of such an 
intensity as to rotate the liquid metal with sufficient vigor as to 
deliver the liquid metal from the enclosed zone to the desired delivery 
point along an enclosed path. 
The rotating magnetic field may be provided in any desired manner. One 
convenient manner uses series of electromagnetic coils surrounding the 
vessel through which electric current is sequentially passed.

DESCRIPTION OF PREFERRED EMBODIMENT 
Referring to the drawings, an apparatus 10 comprises an entry tundish 12 
containing a body 14 of liquid metal, such as molten iron or steel, which 
may have a level detector 16 to control the liquid level in the tundish 
12. 
The tundish 12 is connected to an enclosed container 18 by a horizontal 
passage 20 for the passing of liquid metal from the tundish 12 to the 
container 18. The container 18, which is cylindrical in shape, is 
surrounded by stirring coils 22 which, by the passage of an electrical 
current therethrough, causes a body of liquid metal 24 in the container 18 
to be rotated. 
An upwardly-inclined delivery pipe 26 is arranged tangentially with the 
container 18 adjacent its head 28 to enable liquid metal to be transported 
from the enclosed container to a desired delivery point. 
The magnetic coils 22 produce a powerful rotating magnetic field, generally 
with a strength in the range of about 500 to about 2000 Gauss with a 
frequency of rotation from about 5 to about 400 Hertz, which, in turn 
causes the body of liquid metal 24 to rotate vigorously, creating a 
velocity head, which is converted in the head 28, which may be in the form 
of a volute-shaped head or pressure cap, into vertical motion as the 
liquid metal enters the pipe 26. 
Since the container 24 is wholly enclosed, the liquid metal does not become 
exposed to atmosphere and no seals or mechanical devices are required. 
SUMMARY OF DISCLOSURE 
In summary of this disclosure, the present invention provides a novel 
manner of elevating liquid metals from one location to another by 
effecting centrifugal pumping by employing a strong rotating magnetic 
field. Modifications are possible within the scope of this invention.