US2041312A - Annealing apparatus - Google Patents

Description

F. J. WINDER El AL 2,041,312

ANNEALING APPARATU Original Filed March 26, 1954 2 Sheets-She et 1 M/l/E/VTORS. Mhoer. By LIL. jm'ff.

fifraRA/EK May 19, 1936.

May 19, 1936- F. J. WINDER El AL ANNEALING APPARATUS Original Filed March 26, 1934 2 Sheets-Sheet 2 a W \MW 7 m *JV 1 M. fi 3 Q. 3. Q Q 4 b a t N 9 mm 3 m 1 N@ P Q INVENTORS. F: J. M fldc-v'. BY LL. SW/ ff.

HTTO/P/VEX Patented May 19, 1936 PATENT OFFICE 2,041,312 ANNEALING APPARATUS Frank J. Winder,

Ottawa Hills, and Lincoln L.

Swift, Toledo, Ohio, assignors to Surface Com-. bustion Corporation, Toledo, Ohio, a corporation of New York Application March 26, 1934, Serial No. 717,356 Renewed January 20, 1936 Claims.

This invention relates to heat-treating furnaces of the type embodying a furnace base on which the material is supported during heattreatment' and a heating hood which is removably 5 seated on the base to form a heating chamber for the material.

The object of the invention is to provide a circular furnace of the type indicated with combustion radiator tubes so arranged as to effect uniform heating of annular material such as coiled strip steel.

Referring to the drawings wherein the preferred form of the invention is shown;-

Fig. l is a side elevation showing, on a small scale, four treating stations, the one at the right showing merely a furnace base, the next showing a furnace base'with a charge of material supported thereon, the-next showing a furnace base ,with a protective bell for the material in place on the baseand the one at the extreme left showing a heating hood in place on a furnace base, the view also showing an overhead conveyor for moving the heating hood from one fur- -nace base to another;

Fig. 2 is a vertical sectional view of the improved furnace;

'Fig. 3 is a horizontal section on line 3--3 of Fig. 2;

- Fig. 4 is a side elevation of the furnace shown in Fig. 2;

Fig. 5 1s an enlarged sectional view of an exhauster associated with the outlet end of the several combustion radiator tubes, and

Fig. 6 is an enlarged sectional view of a burner associated with the intake end of the several combustion radiator tubes.

The base of the furnace is indicated at In and is shown as provided with an upstanding circular portion II on the top of which is an annular stool l2 on which the material l3 (see Fig. l) is supported during heating and cooling. The material will ordinarily be covered over by a gas tight metal cover [4 during heating and cooling and-a protective gas will ordinarily be flowed through the cover. The supply pipe for the pro.-

tective gas is indicated at I9 and the exhaust pipe, at 20. The stool l2 has side openings l2 through which the gas enters and leaves the cover. 1

The cover I4 is shown as having a radial foo l5 for seating on a shelf l6 around the base portion II and said foot is provided with a depending circumferential flange ll for dipping into a sand trough l8 around the base It). The cover is .annular in horizontal section. The walls of its central tunnel are indicated at 3| and the tunnel is sufficiently long to permit its lower end, which is closed to extend into a central recess 2| in the top of the upstanding portion ll of the furnace base.

The heating hood is generally indicated at 23. It is open at the bottom and has side walls 26 and a roof 21. The walls are contained within a metal shell 25 having an annular foot 29 on which the side walls 26 are supported. Secured 10 to and surrounding the shell 25 is a depending flange 30 for dipping into the sand trough 18. The shell extends above the roof 21 a sufilcient distance to support a framework 28 which permits the hood as a whole to be lifted. 15

Extending downwardly centrally axially from the top of the hood is a fuel-fired heater generally indicated at 32. This heater comprises two concentric radiator tubes 33 and 34 arranged in radially spaced relation as indicated at 36. The outer tube 33 is closed at its lower end whereas I the lower end of the inner tube 34 is open. Radial spacer fingers 35 between the tubes maintain them in radially spaced relation. The outer tube 33 is supported by the framework 28 and the inner tube 34 is supported by a cap 35 on top of the outer tube. A

Extending radially from the upper end of the outer tube 33 is a branch pipe which connects with an exhauster 45 which, as shown in Fig. 5, 0 comprises a discharge nozzle 48 set to discharge into a Venturi tube 41 which extends from a chambered fitting 48 wherein the nozzle is mounted. Air or other fluid under pressure is delivered to the nozzle by a supplypipe 50'. Since the tubes 33 and 34 are in open communication at their lower ends it will be readily appreciated that the suction effect produced by the exhauster will cause a downdraft in the inner tube 34. 40

At the upper end of the inner tube 34 is a burner 46, the details of which are shown in Fig.

6 and which will now be described. Secured to the upper end of the tube '34 is a tubular extenion 52 having a flaring mouth which is open to the-atmosphere. Positioned centrally axially in the extension as by ribs 5| is a hub 5| having an axial extension for supporting a tubular extension 58 having a chamber 51 at its' outer end. I Fuel gas is delivered to the chamber 51 by a 50 gas supplypipe 54 and extending from the cham-' ber is a gas discharge tube 56. The air for supporting combustion of the fuel discharged from the tube 56 is the air which is drawn into the upper end of the combustion tube 34 by the draft .inlet area thereof.

' fuel tube 56.

produced by the exhauster 45. A shutter 53 in front of the extension 52 controls the effective The fuel discharge tube 56 passes through a chamber 51' to which a preformed combustible mixture of air and fuel gas is delivered by a supply pipe 55. The mixture thus delivered to the chamber'51 flows therefrom through a relatively restricted passage 59 around the tube 56 adjacent its discharge end and serves, when ignited, as a tubular pilot flame for insuring ignition of the fuel issuing from the tube 56. To insure ignition of the mixture issuing from the passage 59, some of the mixture flows from the chamber 51' by way of a ring of outwardly diverging ports 50 which discharge into a shielded combustion groove 6| having an outlet 59 around the discharge end of The mixture issuing from the chamber 51' is initially ignited by inserting a flare into the extension 52.

By introducing the fuel and its combustion supporting air into the combustion tube 34 in the manner described, combustion proceeds relatively slowly as compared with a preformed mixture of air and fuel gas and consequently localized or spot heating of the tube 34 is prevented.

The means for producing radiant heat along the side walls of the heating hood comprises a plurality of horizontally extending vertically spaced combustion radiator tubes generally indicated at 31. Each tube enters the hood tangentially, makes a complete loop therein and then leaves the hood tangentially as clearly shown in Fig. 3. Where the tubes enter and leave the hood, stufiing boxes 42 may be provided. Each tube is individually supported on a number of shelves or ledges 38 projecting from bodies 39 embedded in the walls of the hood as shown in Fig. 2. At the intake end of eachtube is a burner similar to that shown in Fig. 6, and at the outlet end is an exhauster similar to'that shown in Fig. 5.

It is a feature of the invention that adjacent tubes 31 enter and leave the hood at diametrically opposite points withthe result that in one set of tubes the flow of heating gases is in a clockwise direction whereas in the other set the flow is counterclockwise thereby insuring more uniform heating in the hood. Referring to Fig. 3 wherein the arrangement is illustrated, the entering end of the top tube is indicated at 40 and its leaving end at 4|. In the next lower tube the entering end is indicated at 40 and its leaving end at 4|. The burner and exhauster for the 'top tube are indicated at 43 and 44 respectively whereas in the next lower tubes the corresponding parts are indicated at 43' and 44' respectivey.

By entering the tubes 31 tangentially, a substantial portion of each tube inwardly from its burner is straight. Intermixing of the fuel and itscombustion supporting air in this particular portion of the tubes, therefore, proceeds relatively slowly with the result that the entering portion of the tubes is not overheated. The curvature of the tubes accelerates intermixing but not to such degree asto cause objectional spot heating.

An air blower 49 mounted on the framework 28 at the top of the hood 23 supplies pressure air to the several exhausters previously described, as through supply pipe 50 of which the pipes 50 constitute branches. Air from the blower is also utilized for making up the combustible mixture supplied to the several burner chambers 51', the

pressure. Mixing apparatus of this type is well known in the art. The pipes 54 which deliver gas to the several burner chambers 51' are lateral branches from the main gas supply pipe 62.

What is claimed is:

1. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a ring-type cover adapted to be placed over the material and to rest on the base, a heating hood open at the bottom and adapted to be lowered over the cover and to rest on the base, a fuel fired heater arranged in the .middle portion of said cover and comprising: a heat-radiating conduit having its intake and exhaust ends outside of said hood, means for delivering fuel to the intake end 'of the conduit and means at the exhaust end of the conduit tending to draw the fuel through the conduit.

2. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a ring-type cover adapted to be placed over the material and to rest on the base, a heating hood open at the bottom and adapted to be lowered over the cover and to rest on the base, a heater arranged in the middle portion of said cover and comprising: a pair of upright, parallelly extending tubes which extend into said portion from outside of said hood and which are in communication within said portion, means for delivering fuel to the outer end of one of said tubes, and means at the outer end of the other tube tending to draw the fuel through said tubes.

3. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a movable cover adapted to be placed over the material and to rest on the base, a heating hood open at the bottom and adapted to be lowered over the cover and to rest on the base, heating tubes arranged circumferentially along the inside wall of the hood, the ends of each tube extending tangentially out of the hood in opposite directions, and means for applying heat internally to said tubes.

4. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a movable cover adapted to be placed over the material and to rest on the base, a heating hood open at the bottom and adapted to be lowered over the cover and to rest on the base, two sets of heating tubes within the hood, one set leading around the cover in a clockwise direction, and the other set leading around the cover in a counterclockwise direction, the tubes of one set alternating with the tubes of the other set in vertical series.

5. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a heating hood open at the bottom and adapted to be placed over the material and to rest on the base, vertically spaced, horizontally arranged heating tubes, each entering the hood tangentially and making a loop therein and leaving the hood tangentially, and means for applying heat internally to said tubes.

6. Heat-treating apparatus comprising, in combination, a base for the material to be treated, a heating hood open at the bottom and adapted base, vertically spaced, horizontally arranged heating tubes, each entering the hood tangentially and making a loop therein and leaving the hood tangentially, means associated with one end of each tube for supplying fuel thereto, and means associated with the other end of each tube for withdrawing products of combustion from the tube.

7. The combination specified in claim 5, characterized by means projecting from the inner wall of the hood for movably supporting thetubes.

8. Heat-treating apparatus comprising, in combination a base for the material to be treated, a heating hood open at the bottom and adapted to be placed over the material and to rest on the base, vertically spaced, horizontally extending heating tubes, each entering the hood tangentially and making a loop therein and leaving the hood tangentially, and each open at the intake end to the atmosphere, a gas-supply pipe leading to each tube at the intake end thereof, and an aspirator arranged at the'exit end of each tube for inducing gaseous flow through the tube.

9. Heat treating apparatus comprising, in combination, walls forming a chamber for the material to be treated, means for producing heat in said chamber, said means comprising an upright ombustion tube in said chamber and which has its upper and extending through the root of said chamber, a conduit extending upwardly from the lower end of said tube and through the roof of said chamber to form a continuous flow path from the upper end of said tube to the upper end of said conduit, a suction producing device at the upper end of said conduit for drawing air into said tube at the upper end of the latter, and means for discharging fuel downwardly into the upper end of said tube.

10. Heat-treating apparatus comprising, in combination, a base for supporting the material to be treated, a heating hood open at the bottom and adapted to be placed over the material and to cooperate with said base to form a closed heating chamber, heating means in the hood, said means including an outer tube having a closed end inside of the hood and having its other end outside of the hood, an inner tube of smaller diameter arranged within the outer tube and extending adjacent to but spaced from the closed end of the outer tube, the intake end of the inner tube being outside of said hood, means for flowing fuel into the intake end of the inner tube, means for producing draft through the tubes, and said tubes extending between the top and bottom of the chamber.

FRANK J. WINDER. LINCOLN L. SWIFT.

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