Method of inhibiting casting problems

Abstract

The teachings provide a fill tube assembly for a casting mold and methods of using the assembly. The fill tube assembly includes a fill tube having a tubular member with a receiving end, a mold-engaging end and an intermediate portion. The mold-engaging end has a tapered flange radially extending therefrom, the remainder of the tubular member has a substantially, uniform cross-section. A clamping assembly is structured to maintain a substantially leakproof seal at the fill tube, casting mold interface while accommodating dimensional variations. The clamping assembly includes a gasket, a load ring, a clamping plate and a pre-load gap between the clamping plate and the casting mold and optionally includes a dimensional compensating ring. When tightened, the clamping plate biases the load ring against the flange thereby distributing a uniform load against the casting mold, compressing the gasket therebetween while narrowing the pre-load gap to accommodate dimensional variations.

We claim: 
     
         1 . A method of inhibiting casting problems, the method comprising:
 installing an assembly for transferring a molten metal through a joint, the assembly accommodating dimensional variations that occur in the transfer of a molten metal and comprising:   a casting mold operably connected to a fill tube through a joint used in the transfer of a molten metal; and,   a non-rigid, pre-loaded clamping mechanism operably connecting the casting mold to the fill tube to form the joint, the non-rigid, pre-loaded clamping mechanism having a pre-load gap that facilitates application of a substantially uniform compressive load against a flange irrespective of the temperature of the clamping assembly to avoid leakage at the joint;   wherein the installing at least inhibits a casting problem.   
     
     
         2 . The method of  claim 1 , further comprising configuring the clamping mechanism to include the pre-load gap for assembly in a bottom pressure, reverse casting process to substantially reduce leaking in the reverse casting process, wherein the pre-load gap is equal to or greater than the dimensional variation. 
     
     
         3 . The method of  claim 1 , further comprising configuring the pre-load gap size to exceed an expected aggregate dimensional variation and accommodate for an additional and unforeseen dimensional variation occurring during operation of the casting process. 
     
     
         4 . The method of  claim 1 , further comprising configuring the preload gap for a variation selected from the group consisting of thermal expansions, tolerance variations, fabrication defects, assembly errors, and combinations thereof. 
     
     
         5 . The method of  claim 1 , further comprising configuring the operable connection between the casting mold and the fill tube is an engaging of a surface of the casting mold to a surface of the fill tube, and either the casting mold or the fill tube has a tapered non-engaging surface that is configured to mate with the non-rigid, pre-loaded clamping mechanism, the taper configured in an amount ranging from about 15 degrees to about 85 degrees from a horizontal plane to minimize stress concentrations from the non-rigid, pre-loaded clamping mechanism. 
     
     
         6 . The method of  claim 5 , wherein the configuring includes tapering the tapered non-engaging surface in an amount of about 45 degrees from the engaging surface. 
     
     
         7 . The method of  claim 1 , further comprising disposing a gasket material between the engaging surfaces of the first component and the second component, the gasket material comprising a component selected from the group consisting of a high-temperature silicon, a high-temperature polymer, a graphite sheet material. 
     
     
         8 . The method of  claim 1 , wherein the configuring includes configuring the joint to include an airtight connection between the first component and the second component. 
     
     
         9 . The method of  claim 5 , further comprising configuring the joint with a clamping plate with a threaded aperture, the force from the non-rigid, clamping mechanism includes the clamping plate with the threaded aperture. 
     
     
         10 . The method of  claim 1 , further comprising pulling a vacuum to evacuate air within the casting mold. 
     
     
         11 . The method of  claim 1 , further comprising forcing a molten metal having an excess upward through the fill tube into the casting mold. 
     
     
         12 . The method of  claim 1 , further comprising filling the casting mold with the molten metal. 
     
     
         13 . The method of  claim 1 , further comprising draining the excess downward through the fill tube. 
     
     
         14 . The method of  claim 1 , further comprising:
 pulling a vacuum to evacuate air within the casting mold;   forcing a molten metal having an excess upward through the fill tube into the casting mold;   filling the casting mold with the molten metal; and, draining the excess downward through the fill tube.   
     
     
         15 . The method of  claim 1 , further comprising:
 estimating the dimensional variations that could occur during operation of the accommodating assembly;   sealably connecting the casting mold to the fill tube to form the joint, wherein the sealably connecting includes applying a force from the clamping mechanism having the pre-load gap sized to accommodate a variation at least equal to the estimated dimensional variations; and,   maintaining a substantially uniform compressive load against the interface irrespective of the temperature of the clamping assembly through the use of the pre-load gap.   
     
     
         16 . The method of  claim 1 , wherein the casting problem includes a broken fill tube. 
     
     
         17 . The method of  claim 1 , wherein the casting problem includes creating scrap castings. 
     
     
         18 . The method of  claim 1 , wherein the casting problem includes extending casting operation downtime.