Burning ovens for dental materials are these days typically used with an oven hood having an integrated heating means. This construction principle is shown in U.S. Pat. No. 4,139,341, although predecessor constructions, for example pursuant to U.S. Pat. No. 657,202, have shown burning ovens having heating coils in the oven hood.
The material that is to be burned is typically introduced into the burning oven by raising the hood. For example, with the approach of U.S. Pat. No. 4,139,341 in this position of the oven hood the material that is to be burned, and that is placed upon the combustion chamber base, is easily accessible from all sides. It can be easily handled, and the heating means of the oven is well spaced from the material that is to be burned, so that the danger of the operator getting burned is low.
In addition, in this position the oven hood does not cool off much, so that this approach is particularly favorable with regard to practical handling and for achieving a good throughput.
A burning oven of the aforementioned type is also shown in U.S. Pat. No. 5,788,485, (an improvement of U.S. Pat. No. 4,139,341), which illustrates that it is known to provide deposit elements to the side of the combustion chamber base. Such deposit elements are particularly favorable when changing the material that is to be burned. For example, the new material that is to be burned is placed on the left deposit element. The oven hood is opened, and the finished burned material is placed upon the right deposit element using a suitable tool. Only after this is accomplished is the new material that is to be burned taken from the left deposit element and placed upon the combustion chamber base.
The deposited burned material can cool off on the deposit element until it is suitable for further processing. To be able to ensure this, and in particular to avoid tension cracks in the burned material, the deposit element is basically provided in such a way that it poorly conducts the heat away. This can occur in various ways. For example, a special temperature resistant lacquer can be applied to the upper side of the deposit element that makes the heat transfer between the burned material and the deposit element, the base body of which is made of steel, more difficult. The upper surface of the deposit element can also be profiled in a special manner in order to reduce the support surface between burned material and deposit elements.
Although in individual cases this leads to the burned material being seated in a somewhat wobbly fashion upon the deposit element, and in particular such that it moves during vibrations, such an approach is these days typically used, and in order to achieve an adequate resistance to heat transfer, the drawbacks that are connected herewith are tolerated.
Such a burning oven is also offered by the applicant under the designation Programat X1. To prevent the combustion chamber base from heating up the deposit elements, with such a burning oven a certain spatial separation is provided between the support element and the rim of the combustion chamber. On the other hand, it would be more favorable to have a smooth surface here, already for the reason of facilitating cleaning.
USPTO Backgrounds
USPTO Backgrounds