US 5,290,017 AGranted

Cooling cover for batch coil annealing furnace

AssigneeIndugas, Inc.

InventorsKlaus H. Hemsath, James E. Lyon

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Abstract

An improved cooling cover is disclosed for use in bell shaped annealing furnaces. The cooling cover includes a jet nozzle orifice arrangement which develops jet streams from a low pressurized supply of air at ambient temperature in the plenum chamber of the cooling cover. A multitude of free standing jet streams thus impinge the inner cover of the bell shaped annealing stand to produce improved cooling times. Importantly, the plenum chamber includes strategically placed axial jet pump outlets which are effective to draw the jet streams from the cooling cover after they have been in heat transfer contact with the inner cover in a distribution pattern which is not altered so that the work or coils within the inner cover can be more uniformly cooled than heretofore possible. The spent jet streams are withdrawn from the cooling cover in a manner which does not affect the initial impact of the jets with the inner cover while establishing a neutral to slight under pressure at the base of the cooling cover to prevent sand seal upset and hot gas backwash.

Claims24

Dependent claims

An outer cover for use as a staple component of a bell shaped furnace in which said outer cover surrounds an inner cover within which work to be heat treated is placed, said outer cover comprising:

i) an outer cylindrical casing having a longitudinally-extending body section, a closed top end and an open, flanged bottom end;
ii) an inner cylindrical casing having a longitudinally-extending, distributor section, a closed top end and a bottom end;
a plurality of jet nozzle means associated with said distributor section for directing jets of a gaseous medium into heat transfer impingement with said inner cover;
iii) said inner casing disposed within said outer casing to define a longitudinally extending heat transfer annulus between the inside of said outer casing's body section and the outside of said inner casing's distribution section, said heat transfer annulus closed at its bottom axial end and open at its top axial end;
iv) said top end of said inner casing spaced a distance from said top end of said outer casing to define therebetween a plenum chamber, said top end of said heat transfer annulus in fluid communication with said plenum chamber;
and
v) at least one draw opening at a position within said top end of said inner and said outer casings and jet pump means associated with said draw opening for creating jet pump aspiration from said opening for positively drawing gases within said outer cover out of said outer cover whereby pressure within said outer cover adjacent said inner and said outer casing's bottom end is anywhere from neutral to slightly negative while said jet nozzle means impingement pattern on said inner cover is enhanced for heat transfer with work within said inner cover.

4 more elements

In a bell shaped heat treating furnace, comprising a stand upon which work is placed, an inner bell shaped cover surrounding said work removably sealed to said base and an outer, bell shaped cover surrounding said inner cover, the improvement comprising:

a) a plurality of nozzle tubes within said outer cover spaced adjacent to said inner cover, each tube having an orifice outlet, and means to pressurize gaseous medium within said tubes for generating free standing jet streams of a gaseous medium emanating from each orifice into heat transfer impingement with said inner cover;
and
b) jet pump means formed in said outer cover for drawing said jet streams, after impingement with said inner cover, out of said outer cover so that gaseous pressure within said outer cover at a position adjacent the base of said outer cover is neutral to slightly negative for ease in maintaining the sealing of said outer cover.

Dependencies are inferred from the claim text.