Apparatus and process for vulcanizing, adjusted for variable location of

Abstract

An apparatus and process are provided for delivering the precise optimum number of cure equivalents to the exact point of least cure for each tire, though the location of the point varies from one tire to another tire of different geometry, and may vary in tires of the same geometry if there is a change in normal operating conditions. A cure is effected with the aid of a small computer means utilizing only two boundary temperature conditions and the ambient temperature, irrespective of where the boundary conditions are sensed. Preferably, the boundary condition temperatures are obtained without invading the body of the tire, from (1) a measurement of the hot water temperature after it leaves the bladder, and (2) either (i) at the interface of the inner surface of the mold and outer surface of the tire, or (ii) at the surface of the mold, which surface is separated from the outer surface of the tire by the thickness of the mold, or (iii) of the steam outside the mold, the temperature of which steam is measured at a point distally located from the mold's surface. A simplified one-dimensional heat transfer equation containing a response factor (M) applied at several points within a phantom path in the body of the tire, generates a time-temperature profile from which the point of least cure can be tracked and located by the small computer. The time-temperature profiles generated at each point by the small computer mimic the profiles generated in a large computer using a three-dimensional finite difference program, because of the M values generated by the large computer and applied in the small one.