Rotational lance drive and rotational lance injection method
Rotary lance drives for rotating a lance for injecting gas and powdered reagents into molten metal include a reciprocating rotary lance drive and an associated method. A lance mount which facilitates loading of a lance into a lance drive is also disclosed. Various lance designs are described for improving dispersion of reagent and decreasing process time, including lances having non-circular refractory portions and lances having cross-port arrangements for more evenly distributed reagent discharge.
1. A rotary lance drive for rotating a lance for injecting gas and powdered reagents into molten metal, the rotary lance drive comprising:
a main support having a support housing and a pair of rotary bearings arranged external to the support housing respectively adjacent an upper end and a lower end of the support housing;
a hollow shaft extending vertically through the support housing and supported by the pair of rotary bearings for rotation about a vertical axis;
a drive motor drivably connected to the hollow shaft, the drive motor being operable to rotate the hollow shaft about the vertical axis;
a lance mount rigidly connected to the hollow shaft for rotation with the hollow shaft, the lance mount being configured to permit a lance to be removably held by the lance mount for rotation with the lance mount;
a transport pipe extending vertically through the hollow shaft into the lance mount, a bottom end of the transport pipe being connectable to a lance held by the lance mount; and
a swivel coupling receiving a top end of the transport pipe, the swivel coupling permitting connection of a flexible reagent supply hose to the transport pipe and allowing relative rotation between the transport pipe and the supply hose;
wherein the swivel coupling includes an inner part partially extending into an outer part, wherein the swivel coupling is arranged such that reagent from the supply hose enters the swivel coupling through the inner part and exits the swivel coupling through the outer part.
2. The lance drive according to claim 1 , wherein the drive motor is drivably connected to the hollow shaft at a location above the upper end of the support housing.