# US 4,398,474 A · Insulating structure for high temperature devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,474 A - Document ID: US4398474A - Status: Granted - Kind: A - Application number: 06/340,786 - Filed: 1982-01-18 - Granted: 1983-08-16 - Earliest claimed: 1979-02-09 - Assignees: Pyreflex Corporation - Inventors: Charles A. Berg - Web page: https://patentgrep.com/patent/US4398474A ## CPC - F27D 11/04: with direct passage of current through the material being heated - F27D 1/0033: {Linings or walls comprising heat shields, e.g. heat shields} - F27D 9/00: Cooling of furnaces or of charges therein (casings, linings, walls or roofs incorporating cooling arrangements F27D1/12) - F27D: DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE ## Abstract Disclosed is a structure for insulating high temperature devices such as furnaces. The insulating structure comprises a shell enclosing a series of refractory, substantially parallel, spaced-apart sheets, one or more of which may be reflective. The insulating structure stores little heat, is compact, and is lighter than refractory brick. ## Claims ### Claim 1 An insulating structure of low thermal conductivity for minimizing heat loss from a radiant heat source having a temperature above about 1000.degree. F., said structure comprising: a shell of refractory material comprising a front face for placement proximate the radiant heat source and a rear face substantially parallel to said front face, said front and rear faces being joined by walls which together with said faces define a hollow interior, and a plurality of refractory baffles having an emissivity greater than 0.5 disposed within said hollow interior substantially parallel to said front face and defining plural spaces therebetween. ### Claim 2 (depends on 1) The structure of claim 1 wherein said structure defines a furnace muffle. ### Claim 3 (depends on 1) The structure of claim 1 wherein at least one of said front and rear faces comprises a rigid, load-bearing member and said structure defines a refractory tile. ### Claim 4 (depends on 1) The structure of claim 1 comprising at least 10 baffles. ### Claim 5 (depends on 1) The structure of claim 1 wherein said hollow interior contains a gas, and the distance between adjacent baffles is selected to minimize convective heat transfer between adjacent baffles at said structure's temperature of use. ### Claim 6 (depends on 5) The structure of claim 5 wherein the distance between adjacent baffles is less than about 0.15 inch. ### Claim 7 (depends on 5) The structure of claim 5 wherein the distance between adjacent baffles is less than about 0.05 inch. ### Claim 8 (depends on 1) The structure of claim 1 wherein said spaces contain a gas at a subatmospheric pressure. ### Claim 9 (depends on 1) The structure of claim 1 further comprising a reflective surface facing and disposed substantially parallel to said front face, said reflective surface having an emissivity less than 0.5 and being separated from said front face by a plurality of said baffles. ### Claim 10 (depends on 9) The structure of claim 9 wherein said reflective surface has an emissivity less than about 0.2. ### Claim 11 (depends on 1, 9) The structure of claim 1 or 9 wherein said baffles have an emissivity greater than 0.8. ### Claim 12 (depends on 1) The structure of claim 1 wherein said walls comprise refractory members joined by flexible connecting means. ### Claim 13 (depends on 1) The structure of claim 1 wherein said walls comprise a material having a substantially zero coefficient of thermal expansion between room temperature and its temperature of use. ### Claim 14 A furnace comprising: a radiant heat source which in operation is at a temperature in excess of 1000.degree. F., and insulation for confining heat emitted from said heat source, said insulation comprising: a shell comprising a front face of refractory material proximate said heat source and a rear face substantially parallel to said front face, said front and rear faces defining a hollow interior, and a plurality of refractory baffles having an emissivity greater than 0.5 disposed within said hollow interior substantially parallel to said front face and defining plural spaces therebetween. ### Claim 15 (depends on 14) The furnace of claim 14 wherein said insulation comprises a furnace muffle. ### Claim 16 (depends on 14) The furnace of claim 14 wherein at least one of said front and rear faces comprises a rigid, load-bearing plate and said shell defines a refractory tile. ### Claim 17 (depends on 14) The furnace of claim 14 comprising at least 10 baffles. ### Claim 18 (depends on 14) The furnace of claim 14 wherein said hollow interior contains a gas, and the distance between adjacent baffles is selected to minimize convective heat transfer between adjacent baffles at the temperature of operation of said heat source. ### Claim 19 (depends on 18) The furnace of claim 18 wherein the distance between adjacent baffles is less than about 0.15 inch. ### Claim 20 (depends on 18) The furnace of claim 18 wherein the distance between adjacent baffles is less than about 0.05 inch. ### Claim 21 (depends on 14) The furnace of claim 14 wherein said spaces contain a gas at a subatmospheric pressure. ### Claim 22 (depends on 14) The furnace of claim 14 further comprising a reflective surface facing and disposed substantially parallel to said front face, said reflective surface having an emissivity less than 0.5 and being separated from said front face by a plurality of said baffles. ### Claim 23 (depends on 22) The furnace of claim 22 wherein said surface has an emissivity less than about 0.2. ### Claim 24 (depends on 14, 22) The furnace of claims 14 or 22 wherein said baffles have an emissivity greater than 0.8. ### Claim 25 (depends on 14) The furnace of claim 14 wherein said insulation comprises a material having a substantially zero coefficient of thermal expansion between room temperature and the temperature of operation of said heat source. ### Claim 26 An insulating tile for use in shielding high temperature radiant heat sources comprising: a face of refractory material for placement proximate the radiant heat source; a rigid member for providing weight bearing capability to said tile; a plurality of refractory, parallel, spaced-apart baffles disposed outwardly from said face, defining spaces therebetween; and at least one reflective surface disposed outwardly from, parallel to, and facing said baffles, said reflective surface having an emissivity less than about 0.3, the number of said baffles being sufficient to reduce the heat absorbed by said reflective surface to a level sufficient to avoid substantial increases in the emissivity of said reflective surface at the temperature of use of said tile. ### Claim 27 (depends on 26) The tile of claim 26 wherein said reflective surface has an emissivity less than about 0.1. ### Claim 28 (depends on 26) The tile of claim 26 comprising a plurality of said reflective surfaces. ### Claim 29 (depends on 26) The tile of claim 26 wherein said reflective surface is in thermal communication with means for dissipating heat. ### Claim 30 (depends on 29) The tile of claim 29 wherein said means for dissipating heat comprises a surface having an emissivity greater than 0.8. ### Claim 31 (depends on 26) The tile of claim 26 wherein said spaces contain a gas at a subatmospheric pressure. ### Claim 32 (depends on 26) The tile of claim 26 wherein said spaces contain a gas, and the ditance between adjacent baffles is selected to minimize convective heat transfer between adjacent baffles at said tile's temperature of use. ### Claim 33 (depends on 32) The tile of claim 32 wherein the distance between adjacent baffles is less than 0.15 inch. ### Claim 34 (depends on 31) The tile of claim 31 wherein the distance between adjacent baffles is less than 0.05 inch. ### Claim 35 (depends on 26) The tile of claim 26 wherein said baffles have an emissivity greater than 0.5.