Method and apparatus for locating the surface of a liquid metal bath

Claim 2

In the operation of a process wherein a gas is introduced through a lance to a liquid bath, the lance is lowered from above into the vessel which contains said bath, and when the lance initially contacts the bath, the buoyant effect of the bath produces a drop in the apparent weight of the lance, which drop is only momentary as gas from the lance blows the liquid of the bath aside, an improved method of locating the bath surface comprising continuously measuring the distance through which the lance is lowered, continuously measuring the apparent weight of the lance as it is lowered, detecting the momentary drop in the apparent weight, and recording the lance position at the point at which said drop occurs.

Claim 3

An operation as defined in claim 1 in which said bath is ferrous metal and the gas is oxygen.

Claim 4

An operation as defined in claim 1 in which the lance position is continuously recorded and the apparent weight drop of the lance is recorded on the recording of the lance position.

Claim 5

A method as defined in claim 3 in which the weight drop is measured through a computer.

Claim 6

The combination, with a vessel for containing a liquid bath, a lance for introducing gas to said bath, and means for suspending said lance and lowering it into said vessel or raising it therefrom, whereby the buoyant effect of said bath produces a drop in the apparent weight of said lance when the lance initially contacts the bath, which drop is only momentary as gas from the lance blows the liquid of the bath aside, of an apparatus for locating the bath surface, said apparatus comprising means connected with said lance-suspending means for measuring the apparent weight of said lance as it is lowered into said vessel, means connected with said lance-suspended means for measuring the distance said lance travels as it is lowered into said vessel, and means connected with tHe two measuring means for detecting the momentary drop in apparent weight and determining the distance said lance has traveled when said drop occurs.

Claim 7

The combination, with a vessel for containing a liquid bath, a lance for introducing gas to said bath, and means for suspending said lance and lowering it into said vessel or raising it therefrom, whereby the buoyant effect of said bath produces a drop in the apparent weight of said lance when the lance initially contacts the bath, which drop is only momentary as gas from the lance blows the liquid of the bath aside, of an apparatus for locating the bath surface, said apparatus comprising means connected with said lance-suspending means for measuring the apparent weight of said lance as it is lowered into said vessel, means connected with said lance-suspended means for measuring the distance said lance travels as it is lowered into said vessel, and means connected with tHe two measuring means for detecting the momentary drop in apparent weight and determining the distance said lance has traveled when said drop occurs.

Claim 8

A combination as defined in claim 5 in which said suspending means includes a motor-driven drum and a cable winding on said drum and connected to said lance, and said first-named measuring means includes a load cell connected with said cable.

Claim 9

A combination as defined in claim 5 in which said suspending means includes a motor-driven drum and a cable winding on said drum and connected to said lance, and said second-named measuring means includes a position-transmitter connected with said drum.

Claim 10

A combination as defined in claim 5 in which the means for determining the distance the lance has traveled when its weight drops includes a computer connected with said first-named measuring means for transmitting a signal that a drop in weight has occurred, and a recorder connected to said second-named measuring means and to said computer.

Claim 11

A combination as defined in claim 8 in which said computer includes means for preventing transmission of signals unless the lance weight is within a predetermined range and the lance position is within a predetermined distance of the bath surface.

Claim 12

A combination as defined in claim 5 in which said suspending means includes a motor-driven drum and a cable winding on said drum and connected with said lance, said first-named measuring means includes a load cell connected with said cable, said second-named measuring means includes a position-transmitter connected with said drum, and means for determining the distance the lance has traveled when its weight drops includes a computer connected with said load cell and a recorder connected with said position-transmitter and with said computer.