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US 4,802,844 AGranted
High capacity, retractable furnace hearth
AssigneeGas Research Institute
InventorsTimothy J. Kuhn, James W. Bender, Arvind C. Thekdi
Life of this patent
Estimating the term…
Abstract
A retractable, roller hearth for use in an industrial heat treat furnace is disclosed whereby the alloy rollers are retracted from their load bearing position when the furnace heat treat processes are underway thus maintaining the rated load capacity of the furnace. A plurality of guided rail support posts and guided, sealed lift posts accurately assure straight line vertical motion of the refractory base enabling contact between fibrous rope seals to seal the hearth from the cooler, lower portions of the furnace when the hearth is in a raised position.
Claims29
A retractable roller hearth arrangement for use in an industrial heat treat furnace having a furnace chamber surroudnign said hearth into which metallic workpieces placed in a work tray are to be heat treated, said hearth comprising:
- (a) a refractory base having a bottom surface, a top surface, and a closed peripheral edge surface extending between said bottom and top surfaces;
- (b) tile support means extending from said top surface of said refractory base for supporting, when actuated, said work tray when said furnace chamber is heat treating said work;
- (c) roller rail means positioned on said top surface of said refractory base and including a plurality of rollers for supporting, when actuated, said work tray and permitting movement of said tray into and out of said furnace chamber in a rolling, anti-friction bearing manner;
- (d) hearth lift means for moving said roller rail means relative to said tile means while maintaining said refractory base within said furnace chamber for selectively actuating said roller rail means to support said work tray when said tile support means is not actuated and selectively actuating said tile support means when said roller rail means is not actuated whereby the load-sustaining capacity of said rollers is maintained.
1 more element
A batch type, industrial heat treat furnace for heat treating ferrous workpieces placed in a work tray comprising;
- a sealed furnace chamber;
- means for heating said furnace chamber;
- fan means for circulating a heat treating atmosphere gas within said furnace;
- a refractory base having a bottom surface, a top surface, and a closed peripheral edge surface extending between said bottom and top surfaces;
- tile support means extending from said top surface of said refractory base for supporting, when actuated, said work tray when said furnace chamber is heat treating said work;
- roller rail means positioned on said top surface of said refractory base and including a plurality of rollers for supporting, when actuated, said work tray and permitting movement of said tray into and out of said furnace chamber in a rolling, anti-friction bearing manner;
- hearth lift means for moving said roller rail means relative to said tile means while maintaining said refractory base within said furnace chamber for selectively actuating said roller rail means to support said work tray when said tile support means is not actuated and selectively actuating said tile support means when said roller rail means is not actuated whereby the life of said hearth arrangement is increased.
4 more elements
A rectangular, retractable roller hearth for use in a rectangular furnace chamber surrounding said hearth, said hearth comprising;
- (a) a refractory base member having a top surface, a bottom surface and a peripherally extending edge surface therebetween;
- (b) said refractory base having a first plurality of openings, spaced along a first longitudinally-extending centerline extending therethrough, said refractory base having a second plurality of openings spaced along a second longitudinally-extending centerline extending therethrough, said second centerline spaced laterally from said first centerline;
- (c) a first longitudinally-extending rail centered on said first centerline and extending from one end to the opposite end of said refractory base member, a second longitudinally-extending rail centered on said second centerline and extending from one end to the opposite end of said refractory base member, each rail supporting a plurality of alloy rollers spaced therealong;
- (d) a plurality of longitudinally-extending ceramic tiles extending from said top surface a fixed distance relative to the position of said rollers;
- (e) a rail support post extending through each of said first and second plurality of openings;
- each rail support post having one end connected to one of said first and second guide members and an opposite end connected to said furnace chamber at a point spaced from said bottom surface of said refractory base;
- each plurality of openings having a tubular collar member inserted therein from said bottom surface closely surrounding said rail support post;
- (f) a structural member secured to said bottom surface at the intersection of said bottom surface with said edge surface to define a peripherally extending framework supporting said refractory base;
- (g) a first and second structural beam member laterally extending from one side to the other side of said refractory base member and secured to said structural member;
- (h) a first, second, third and fourth lift post, each post extending through said furnace chamber and having an end outside said furnace chamber secured to lift means for moving said lift post relative said furnace chamber and an end inside said furnace chamber secured to one of said beam members, said inside end of said first list post positioned at a point underlying said first centerline, said inside end of said second lift post underlying said second centerline, said inside end of said third lift post underlying said first centerline at a point removed from said first lift post and said inside end of said fourth post underlying said second centerline at a point removed from said second post whereby said hearth is moved in a straight line motion by said lift means to move said tiles above or below said alloy rails.
7 more elements
Dependencies are inferred from the claim text.