US 5,290,189 AGranted

High temperature industrial heat treat furnace

AssigneeGas Research Institute

InventorsKlaus H. Hemsath, James E. Lyon

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Abstract

Modifications are provided to a standard, batch type industrial heat treat furnace of a hot wall design which permit the furnace to be operated efficiently at high temperatures. The furnace is of a cylindrical design having a forward heat treat chamber and a rearward plenum chamber with a flat bulkhead plate in-between the chambers. The bulkhead has exit and inlet openings permitting wind mass to flow to the heat treat chamber and back to the plenum chamber. The bulkhead has a plurality of radially extending slits formed therein which permit the bulkhead to remain flat despite temperature and pressure gradients resulting in expansion/contraction of the bulkhead. Additionally, the furnace includes a closed end muffle within the heat treat chamber into which work to be heat treated is placed. A water cooled spring biasing support is provided for the closed end of the muffle to resist downward deformation of the muffle at high temperatures. The furnace additionally includes a heat shield circumscribing the furnace casing to provide a cooling air space for preheating burner combustion air while minimizing heat losses and the cost of furnace insulation.

Claims29

Dependent claims

A cylindrical, high temperature industrial heat treat furnace comprising:

a heat treat section defined by a generally cylindrical furnace casing having a circular forward end and a flanged, rearward end, said forward end being the loading end of said furnace;
a plenum section defined by a generally cylindrical plenum casing having a circular flanged forward end and a rearward end, said rearward end being the rear end of said furnace;
said flanged forward end of said furnace casing and said flanged rearward end of said plenum casing abutting one another in a secured manner;
a circular bulkhead having outer edge face surfaces inbetween said flanged ends and defining a heat treat chamber extending f rom one side of said bulkhead within said heat treat section and a plenum chamber extending from the opposite side of said bulkhead within said plenum section;
said bulkhead having a central underpressure opening and a pressure exit opening spaced radially outwardly from said central opening,
fan means within said plenum chamber f or developing a source of pressurized wind mass within said plenum chamber leaving said plenum chamber through said pressure exit opening into said heat transfer chamber and returning to said plenum chamber through said central opening;
burner means for heating said wind mass to an elevated temperature;
sealing means at said flanged ends for sealing said circular outer edge face surfaces of said bulkhead within said flanged ends while permitting said bulkhead edge to radially move within said flanged ends to accommodate thermal expansion and contraction;
and
at least one radial slit formed in said bulkhead extending to the outer edge of said bulkhead from a position radially outwardly from said pressure opening whereby said bulkhead remains flat despite expansion and contraction.

7 more elements

A cylindrical high temperature industrial heat treat furnace comprising:

a cylindrical heat treat section having an open forward end and a rearward end defined by a cylindrical heat treat, gas tight casing and fibrous furnace insulation secured about the interior of said heat treat casing to define a heat treat chamber therein;
a cylindrical closed end plenum section secured to said rearward end of said heat treat section,
a closed end, cylindrical, imperforate muffle having a flanged forward end, said flanged forward end adjacent said forward end of said heat treat section and said muffle's closed end within said heat treat chamber;
an anchor pin secured to and extending from said closed end;
a pivot bar attached at one end to said anchor pin in a pivotal manner;
a spherical collar mounted adjacent said heat treat casing for swiveling, said collar having a central opening in fluid communication with an opening in said heat treat casing and through which said pivot bar extends;
an adjustable compression member mounted on said pivot bar;
a spring effectively compressed between said compression member and said heat treat casing by which said closed end of said muffle is pulled upwardly by the compression force of said spring whereby said muffle is supported against downward deflection at elevated temperature by said spring.

5 more elements

A cylindrical high temperature industrial heat treat furnace comprising

a cylindrical heat treat section having a forward and rearward end and defining therein a heat treat chamber;
a cylindrical plenum section sealingly secured to said heat treat casing and defining a cylindrical plenum chamber therein;
a cylindrical closed end, imperforate muffle within said heat treat chamber having a work receiving open end adjacent said heat treat section forward end;
a circular bulkhead in-between said heat treat and said plenum sections having a central under-pressure opening and a plurality of distributor tube pressure exit openings spaced radially outwardly from said return opening,
a plurality of distributor tubes secured to said exit openings and longitudinally extending within said heat treat chamber, each distributor tube having a plurality of jet openings facing said muffle;
fan means and burner means within said plenum chamber for developing a source of wind mass at high pressure and temperatures in excess of about 1700.degree. F. within said plenum chamber, said wind mass exiting said plenum chamber through said exit openings and returning through said central opening, and
a plurality of circumferentially spaced, radially-extending slits formed in said bulkhead extending from a position radially outwardly of said exit openings to the outer edge of said bulkhead;
and
slip joint means between said plenum and heat treat sections allowing said bulkhead to expand and contract during operation of the furnace while retaining said bulkhead.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/112,145Filed 26 Aug 1993
Granted: 1 Mar 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

F27B 5/16
Details, accessories or equipment specially adapted for furnaces of these types: arrangements of air or gas supply devices
F27B 2005/162
Gas inflow or outflow: through closable or non-closable openings of the chamber walls
F27B 2005/167
Means to circulate the atmosphere: the atmosphere being recirculated through the treatment chamber by a turbine
F27D 1/0033
Linings or walls: linings or walls comprising heat shields, e.g. heat shields