Abstract: A head for a line trimming apparatus includes a body member and a detachable cover which may include a replaceable insert for connecting the head to a drive shaft of a line trimming apparatus. The body member includes opposed openings and a filament receiving channel for inserting an elongated flexible cutting filament into the head for retention thereon. A spring biased clamp is supported on the body member and is engageable with the filament portion residing in the channel to releasably retain the filament connected to the head. An actuator button projects through an opening in the body member and is operable to be pressed to cause the clamp to release forcible engagement with a filament so that the filament may be removed and replaced. In one embodiment the clamp and actuator are an integrally formed part and the filament projects through openings formed in spaced apart arms of the clamp member.

Abstract: A device for blowing gas under pressure into a bath of liquid metal comprises a mass of refractory material which is porous at least at an inner portion thereof and placed into a metallic container constituted by an outer metallic envelope closed at one of the ends thereof by a bottom member through a central portion of which a conduit extends for feeding a gas under pressure to the porous inner portion of the mass. A deflector is provided fluid-tightly connected to the bottom inwardly of the envelope in which the wall of the deflector extends parallel to that of the envelope but short of the length of the latter. This permits, on the one hand, to avoid penetration of liquid metal between the envelope and the mass of refractory material to a point where it would block the gas feeding conduit and, on the other hand, to canalize the gas through the porous portion of the mass. The present invention relates likewise to a method of making the above device.

Abstract: The refractory piece permeable to gases according to the invention is designed to be incorporated in the inner refractory lining of a metallurgical container so that one of its surfaces will be in contact with the molten metal bath in said container, the opposite surface being equipped with means for introducing a gas under pressure.This piece, whose shape is generally hexahedral, consists essentially of a mass of nonporous refractory material that has a number of local discontinuities 8 extending throughout the piece along its height h between the surface in contact with the molten metal and the opposite surface. In an advantageous method of embodiment, the local discontinuities 8 are obtained by an assembly 1, in a metal casing, of nonporous refractory elements 2, in the form of plates and which are placed side by side along their large lateral surfaces, without any material gaskets or seals between them.The piece according to the invention is easy to make.

Abstract: The refractory piece permeable to gases according to the invention is designed to be incorporated in the inner refractory lining of a metallurgical container so that one of its surfaces will be in contact with the molten metal bath in said container, the opposite surface being equipped with means for introducing a gas under pressure.This piece, whose shape is generally hexahedral, consists essentially of a mass of nonporous refractory material that has a number of local discontinuities 8 extending throughout the piece along its height h between the surface in contact with the molten metal and the opposite surface. In an advantageous method of embodiment, the local discontinuities 8 are obtained by an assembly 1, in a metal casing, of nonporous refractory elements 2, in the form of plates and which are placed side by side along their large lateral surfaces, without any material gaskets or seals between them.The piece according to the invention is easy to make.