Convective heat transfer within an industrial heat treating furnace
AssigneeGas Research Institute
InventorKlaus H. Hemsath
Life of this patent
Estimating the term…
Abstract
An improved heat transfer arrangement for use in a unique multi-function, industrial heat treat furnace which employs a sealed, closed end, heat exchanger shell member containing the work. The heat transfer arrangement includes a totally contained, internal recirculation system which develops an especially configured annular jet stream that produces highly efficient, convective heat transfer with the shell member. After heat transfer between the entrained gases in the jet stream with the shell member has occurred, the jet flow is reversed at one end of the shell and impinged against the workpiece, the spent stream being reformed into the annular jet at the opposite end of the shell member.
Claims16
An industrial heat treat furnace comprising:
- (a) an insulated furnace casing defining an enclosure;
- (b) a sealed, imperforate, generally thin walled, shell member having a closed end within said enclosure, said shell member containing an atmospheric gas initially at a first temperature;
- (c) at least one workpiece within said shell member;
- (d) source means remotely situated from said shell member for generating a fluid medium at a second temperature different than said first temperature;
- (e) heat transfer means in communication with said source means and situated within said enclosure relatively close to said shell member to effect heat transfer between said fluid medium at said second temperature and the exterior of said shell member's thin wall so that the temperature of said shell member's thin wall approaches said second temperature;
- and
- (f) jet pump means within said shell member producing an annular jet of atmosphere gas traveling the length of said shell member, said annular jet having an initial diameter when formed at a position remote from said closed end smaller than the inside diameter of said shell member, said jet pump means causing said annular jet to expand into contact with said shell member's thin wall as it travels the length thereof to effect significant heat transfer between said shell member's thin wall and that portion of said atmosphere gas entrained within said jet, and thereafter to impinge said jet against said workpiece to cause heat exchange therebetween.
An industrial heat treat furnace comprising:
- (a) an insulated furnace casing defining an enclosure;
- (b) a sealed, imperforate, generally cylindrical, thin walled shell member within said enclosure, said shell member containing an atmosphere gas initially at a first temperature;
- (c) at least one workpiece within said shell member;
- (d) source means remotely situated from said shell member for generating a fluid medium at a second temperature different than said first temperature;
- (e) heat transfer means in communication with said source means and situated within said enclosure relatively close to said shell member to effect heat transfer between said fluid medium at said second temperature and said shell member so that the temperature of the shell member's thin wall approaches said second temperature;
- (f) means within said shell member to generate a jet of entrained atmospheric gas and to effect convective heat transfer from said thin wall of said shell member to said atmospheric gas within said jet and to effect convective heat transfer from said entrained atmospheric gas to said work;
- (g) said means to generate a jet including jet pump means to originate an annular jet of said atmospheric gas which expands into contact with said shell member's wall to effect heat transfer between said shell member's wall and said expanded jet stream as said atmospheric gas within said expanded jet stream travels a length of said cylindrical shell member, and recirculating means for directing said gas within said expanded jet stream after it has travelled some portion of the length of said shell member to impinge against said workpiece as a jet stream to effect heat transfer therebetween and then to said jet pump means;
- and
- (h) said recirculating means includes diverter plate means at one of said shell member's ends for reversing the axial flow direction of said annular jet as a smaller diameter annular jet to cause impingement with said work.
Dependencies are inferred from the claim text.