US 3584852 A
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United States Patent 42,42 R, 43.D1G.2; 126/91 A  lnventor Claude l-l. Leland Grosse Pointe Woods, Mich. [211 Appl. No. 852,393  Filed Aug. 22, 1969  Patented June 15, 1971  Assignee Super Steel Treating Co.
[541 HEAT-TREAT FURNACE 3 Claims, 3 Drawing Figs.
 US Cl [51 1 Int. Cl  Field of Search  References Cited UNITED STATES PATENTS 1,744,817 1/1930 Ward 263/DIG.2
2,910,285 10/1959 Harris 3,100,632 8/1963 Mohring Primary Examiner-John J. Camby Attorney-Winnie & Romanski ABSTRACT: A heat-treat furnace having at least one radiator channel along a wall having heat radiators therein with a blower exhausting air into the channel horizontally at one end of the channel and with the channel exhausting air horizontally into the furnace interior at the other end of the channel; the blower suction side drawing air horizontally from the furnace interior so that heated air is recirculated in the furnace interior horizontally to effect homogenous heating of metal items in the furnace from top-to-bottom; side-to-side,and end-to-end by air recirculation in horizontal travel to oppose and reduce gravitational and density influences toward stratification.
. sum 2 nr 2 INVENTOR CAM/0f ZZZ/4N0 HEAT-TREAT FURNACE This invention relates to a heat-treat furnace having means for recirculating heated air horizontally to oppose and reduce gravitational and density influences toward Stratification to effect homogenous heating of metal items in the furnace.
While heat-treat furnaces have been employed heretofore, the several devices of the prior art have not proven entirely satisfactory inasmuch as they are complicated in design and construction, expensive to manufacture, not of desirable efficiency, and do not treat the metal items with desirable uniformity.
With the foregoing in view it is a primary object of the invention to provide a heat treat furnace which is simple in.
design and construction, inexpensive to manufacture, has increased efficiency, and treats the metal items with improved uniformity.
An object of the invention is to provide a heat treat furnace which recirculates the air over the radiators and over the metal items in a horizontal path to combat and reduce gravitational and density influences toward stratification to produce a more evenly heated furnace and to impart heat distribution more evenly and homogeniously to the metal parts to obtain greater efficiency and to obtain more uniform treatment of the metal items.
An object of the invention is to provide a heat-treat furnace which imparts heat to the metal items at substantially the same rate ofincrease to all the metal items irrespective of their position and location in the furnace so that the treatment is more uniform. I
These and other objects of the invention will become apparent by reference to the following description of the heattreat furnace embodying the invention taken in connection with the accompanying drawings in which:
FIG. 1 is an end elevational view ofthe furnace;
FIG. 2 is a side elevational view of the furnace; and
FIG. 3 is an enlarged horizontal cross-sectional view of the furnace shown in FIG. 2 taken on the line 3-3 thereof.
Referring now to the drawings wherein like numerals refer to like and corresponding parts throughout the several views, the heat-treat furnace l disclosed therein to illustrate a preferred dual heating system embodiment of the invention comprises a floor 11, sidewalls l2 and 13, end walls 14 and 15, and a ceiling 16. A door 17 in one wall, such as end wall 15, is provided for placing metal items in the furnace l0 and removing them therefrom.
Baffle walls 18 and 19 lie parallel, adjacent, and spaced from sidewalls l2 and 13 respectively creating radiator channels 20 and 21. The baffle walls 18 and 19 are closed off at top The radiators 22 may be U-shaped as shown and gasfired with.
the ignited gasses blown down one stack 23 and up the other stack 24 via the connecting U-portion 25 at the bottom. The.
radiators 22 may be individually injected by individual units or collectively by a master burner. The radiators 22 may be individually or collectively exhausted. The shape, firing fuel, injection and exhaust of the radiators may be selectively engineered.
Air delivery ports 26 and 27 supply air to the channels 20 and 21 respectively. Air return ports 28 and 29 lead from the interior of the furnace 10. The ports 26-29 may be in a furnace wall such as the end wall M.
A blower 30 is located adjacent the ports 26 and 28 and a blower 31 is located adjacent the ports 27 and 29. The suction sides 32 and 33 of the blowers 30 and 31 communicate with the return ports 28 and 29 respectively. The exhaust sides 34 and 35 of the blowers 30 and 31 communicate with the supply ports 26 and 27 respectively.
Supply port 26 delivers air to the channel 20 and over the radiators 22 therein to the interior workpiece area of the furnace 10. Supply port 27 delivers air to the channel 21 and over the radiators 22 therein to the interior of the furnace 10. The air from the interior of the furnace 10 is transmitted back to the blowers 30 and 31 via the return ports 28 and 29 respectively after it has passed over and/or through the metal. items in the furnace l0.
The air is thus recirculated in the dual heating system in the preferred embodiment. The invention includes a single system in a furnace such as the blower, channel, radiators, and ports on one side of a furnace. In either embodiment the heated air is introduced to the workpiece area at one end and removed at the other end insuring complete passage relative to the metal items.
While air is referred. to as the heated recirculated gaseous medium, it will be understood that selective gaseous mediums may be used such as nitrogen, hydrogen, etc., singly and in combination, to formulate a desired atmosphere.
The blowers are preferably outside the furnace 10 work piece area as shown by virtue of the walls defining and forming the blower housing and the ducts leading to and from the ports 26-29. The end wall 14 may be located beyond the blowers if desired.
In operation, the blowers 30 and 31 receive air from and exhaust air to the furnace l0 horizontally and recirculate the air horizontally through the channels 20 and 21 and through the workpiece area of the furnace 10. In the horizontal travel of the air through the workpiecearea, the heated air passes over and/or through the. workpieces horizontally. This combats convectional relative density andgravitational characteristics of the heated air and reduces and minimizes stratification due to their influence so that the air is substantially uniform in temperature as it contacts the metal items thus imparting heat to them at a substantially uniform rate and at a substantially even ambient temperature resulting in substantially evenly treated metal items relative to one another and from batch to batch.
The-furnace of the invention as described hasbeen found to be more economical, quicker, and productive of better desired quality of treatment. The appended claims define the scope of protection. of the invention.
l. A furnace for heat treating such as annealing, normalizing, and stress-relieving metal items; said furnace having a structure and operation comprising,
a floor for supporting metal items to be treated; first and second sidewalls, first and second end walls rising from said floor, a ceiling wall on said sidewalls and end walls, and a door in one said wall for placing and removing metal items in said furnace,
a baffle'wall lying parallel to and relatively closely spaced from said first sidewall;
said baffle wall leading from said first end wall and terminating short of said second end wall;
said baffle wall and said first sidewall creating a radiator channel having an open end spaced from said second end wall,
heat radiators between said first sidewall and said baffle wall in said radiator channel,
a blower having a suction side and an exhaust side at said first end wall, an air return port in said first end wall leading from the furnace interior to said blower suction side,
an air delivery port in said first end wall leading from said blower exhaust side to said radiator channel between said the air in moving from said radiator channel to said return port under influence of said blower passing horizontally over the metal items to impart heat to the metal items;
said blower recirculating the air horizontally in the furnace to effect homogeneous heating of the metal items from top-to-bottom, from side-to-side, and from end-to-end by horizontally recirculating heated air relative to the metal items to oppose and reduce gravitational and density influences toward stratification.
2. In a furnace as set forth in claim 1,
a second baffle wall lying parallel to andrelatively closely spaced from said second sidewall creating a second radiator channel therebetween;
heat radiators in said second radiator channel; and
a second air delivery port in said first end wall leading from said blower exhaust side to said second radiator channel. 3. In a furnace as set forth in claim 1, a second baffle wall lying parallel to and relatively closely spaced from said second sidewall creating a second radiator channel therebetween; heat radiators in said second radiator channel,