Single use transportable reaction crucible for a metallothermic welding portion

#The present invention relates to a single use transportable reaction crucible for a metallothermic, especially aluminothermic, welding portion and includes a crucible shell having a cylindrical casing and a flat floor and a lid and in the crucible shell a refractory lining that receives the welding portion and that is provided in its base with an opening that can melt open.

#Such a reaction crucible is known from DE 197 02 410 C1. In the known reaction crucible, the actual reaction crucible is stamped or riveted into a metal crucible shell in the form of a lining made of a sand mixture. For this reason the shell must be made from a high-strength, metallic, heavy material. A lighter and less expensive material such as cardboard, plastic, or the like cannot be used. Since the lining has a flat floor corresponding to the flat floor of the crucible shell, it does not facilitate the flow of the molten metal to the bottom opening. In the lining the welding portion is either fed into a conventional can or into a conventional plastic sack or into another container. When the reaction crucible is used, the lid is removed and the welding portion is ignited using an ignition rod, whereupon the lid is replaced. The metal crucible shell requires a separate removal from the application site.

#The object of the present invention is to provide a reaction crucible of the aforementioned type in which less expensive materials can be used for the crucible shell and the actual reaction crucible is securely maintained in the crucible shell and has an inclined floor.

#Exemplary embodiments of the reaction crucible in accordance with the invention shall now be explained in more detail using the enclosed figures, in which:

#FIG. 1 is a vertical section through a reaction crucible;

#FIG. 2 is a vertical section through a lid with dust filter; and

#Provided in the transportable reaction crucible 1 illustrated in FIG. 1 is a crucible cover or shell 2 that has a cylindrical casing 3 and a flat floor 4. Casing 3 and floor 4 are made from cardboard that is provided on its interior with a moisture-blocking aluminum lining K. The floor 4 has a floor section 4a and a circular flange 4b. The floor is glued to the casing 3 such that the free lower edge 3a of the casing and the free edge 4c of the flange lie in the same plane. The floor thus designed stiffens the crucible cover.

#Placed on the flat top surface of the floor section 4a is the flat underside 5a of a support disc 5 that is made of a first refractory material F1, the exterior diameter of which is adapted to the interior diameter of the casing. The top surface 5b of the support disc forms a cone in the direction of a central opening 5c. The central opening 5c tapers downward in a cone. The exterior jacket surface 5d of the support disc 5 tapers upward slightly in a cone shape.

#For receiving a welding portion S to be introduced into the reaction crucible as free fill, sitting on the conical top surface 5b of the support disc 5 is the underside 6a of the floor 6 of a separately produced reaction vessel 7 that is inserted into the crucible shell 2 and is made of a refractory material F2, the underside also being conical in conformity with the conicity of the top surface 5b of the support disc. The top surface 6b of the floor 6 inclines in a cone, in conformity with the conicity of the underside 6a, to a central discharge opening 6c formed in a guide projection 6d that extends downward from the underside 6a of the floor 6 and engages in the conical opening 5c of the support disc. The axial length of the hollow guide projection 6d, which is integral with the floor 6, should be dimensioned such that it is flush with the underside 5a of the support disc. A seal 8 that is meltable by the metallothermic reaction is inserted in the opening 6c. The cardboard floor under the opening 6c burns. However, it is also possible to provide the floor under the opening with a pre-punch.