Design Considerations in High-Temperature Devices

DOE-HDBK-1132-99

Design Considerations in High-Temperature Devices include methods to

accommodate the expansion and movement of materials during heat-up, the

possibility of auxiliary cooling of the outer structural shell, selection of

materials for low expansion coefficients, and the selection of materials for

corrosive resistance at operating temperatures the component will actually

experience.

Penetrations/Sleeves through the melter shell will usually encounter the

largest temperature differentials during normal operation. Special

consideration should be afforded the selection of materials for corrosive-

resistant properties and strength characteristics at the operating temperatures

involved. In some cases, the use of a sacrificial inner liner material may be

worthwhile, keeping in mind that the details of remote replacement of the

component will have to be a part of the design.

Warping and Alignments are critical concerns in melter design. Because of

the operating temperatures involved, materials are going to distort. Selection

of materials, innovative use of refractories, and the ability to cool areas of the

melter that are not integral to the glass melting function can be used to

minimize warping. Movement of materials during heat-up is a reality that

should be factored into the design.

Off-Gas Processing . Off-gas from melter- and canister-filling operations

2.14.12

should be processed through some type of off-gas collection and treatment

system. The collection portion of typical systems includes a ducted suction

arrangement to maintain a slightly negative pressure on the melter " ool"

chamber and the discharge cavity, which in turn interfaces with the canister

filling operation. The amount of actual airflow from these areas should be

balanced against loss of heat from both melter chambers and effects on the

glass discharge stream while maintaining adequate collection of the off-gas

stream. For example, excess airflow from the discharge chamber can affect

the glass pour stream by causing wavering, a less viscose glass stream, and

the formation of glass " ird nests"in the canisters being filled.

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