US2182616A - Apparatus for continuous heating and cooling of metals - Google Patents

Description

1939- K. A. J.UTHE 2,182,616

APPARATUS FOR, CONTINUOUS HEATINGIAND coom'ue on METALS Filed July 9, 1938 .4 Sheets-Sheet 1 I I 1" I Krz'sEian 4 322959 ATTORNEYS.

Dec. 5, 1939.

K. JUTHE AE'PARATUS FOR'CONTINUOUS HEATING AND COOLING 0F METALS Filed July 9, 1938 4 Sheets-Sheet 2 =1 26 z z z 2 1-7 I 23 M" 1-45 v M 29 25 i, J 1 i- (k ":1 MI: :1-

. a INVENTOR.

Krzsiaanfl cfatfie BY ww ATTORNEYS.

Dec. 5, 1939. K. A. JUTHE 2,182,616

ArPAkA-rus FOR commuous HEATING. AND coouue OF mmps Filed Jul 9, 1938 4 Sheets-Sheet 3 INVENTOR 3 3 L J A f ATTORNEYS.

BY 9W 5, K.' A. JUTHE 2,182,616

AP PARATUS FOR CONTINUOUS HEATING AND COOLING 0F METKIJS Filed Ju1y;9., 1938 4 Sheets-Sheet 4 INVENTOR Krisfiz'am .4 cfwii/wz.

ATTORNEYS.

Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR CONTINUOUS HEATING AND COOLING OF METALS Application July 9, 1938, Serial No. 218,409

6Claims.

This invention relates to a new apparatus for continuously heating and cooling ferrous and non-ferrous metals under controlled atmospheric conditions.

5 It is designed especially for eflicient continuship, and provide both units with automatic direct-connected work feeding devices whereby the work is automatically and continuously fed through the furnace and cooling units. During 15 the passage of the work through said units it is subjected to an artificially produced neutral or gaseous atmosphere which is maintained within close limits of control at all times in both units, and especially at the charging end of the furnace retort and the discharge end of the cooling unit. As a result, the work is not only continuously and rapidly fed through both units but is treated under such closely controlled atmospheric conditions as to eliminate any tendency of the surface of 25 the work to scale, decarburize, or oxidize.

Heretofore the conventional method for cooling the work after it left the heating chamber of the furnace was to pass it through an extended cooling chamber equipped with an endless conveyor,

30 such as a belt or a roller conveyor.

One objection to the conventional method was the floor space required for setting up the cooling chamber and the shipping space required for shipping the cooling chamber from point of manu- 36 facture to point of use.

I Due to the character of the, conveyor employed in the cooling chamber, the cooling chamber necessarily bad to be of considerable length in order to provide adequate cooling time for the 40 work, being usually approximately three times as long as the furnace chamber.

In addition to this objection, another objection was that proper atmospheric control could not be maintained at all times and in all areas of the 5 furnace chamber and cooling chamber. This was due to a number of factors, chief among which was the difficulty of relating the feed of the work through the furnace chamber to the feed of the work through the extended cooling chamber with- 50 out undue loss of the neutral or gaseous atmosphere as the work discharged from the furnace chamber into the cooling chamber and as the work discharged from the cooling chamber.

My present invention avoids these objections.

55 According to it, the furnace unit is provided with a rotatable retort having an integral internal spiral screw conveyor. This retort extends from end to end of the furnace chamber and through both ends of the furnace. being supported at its ends on anti-friction bearings. 5 At its charging end the retort is provided with a loadingdrum having an internal loading device for automatically loading the work into the retort and at the same time for retarding the escape of atmosphere from the retort. At its discharge end,the retort is fastened directly to an enlarged cooling drum having an internal spiral screw conveyor. The'cooling drum is likewise rotatably supported on anti-friction bearings, and being directly connected to the retort, continuously rotates in unison therewith.

The discharge end of the cooling drum is provided with a work discharge chute equipped with a normally closed shutter which automatically opens preferably once each revolution of the cooling drum to discharge the finished work and instantly closes to prevent the escape of the neutral or gaseous atmosphere therefrom. The openng and. closing of the discharge shutter is positive and automatic, being controlled by a cam or equiv- 5 alen't device.

The cooling drum itself is continuously cooled with water or other cooling fluid by spray nozzles disposed exteriorly thereof. The water discharged from said nozzles cools the drum as it 0 revolves and drains into a tank beneath the drum, the level of the water in such tank being so adjusted that the drum is partially submerged in it as it rotates therethrough.

The retort and cooling drum are driven as a v unit from any suitable power source, as for example, a motor operated variable speed drive and reduction unit, the discharge end of the. retort being flanged and d rectly attached to the intake end'of the cooling drum and the drive sprocket .40 being also bolted to the retort flange preferably by the same bolts which couple'these ends. of the retort and cooling drum together.

The necessary artificial atmosphere required during heating and cooling of the work to prevent discoloration, scaling, decarburization or I oxidation of the surface 'of thework and to ensure bright or clean annealing, is supplied from a separate atmospheric unit. This unit discharges axially into the cooling drum at the work discharge end of said drum, the atmosphere thus supplied passing through the drum and through the charging chamber of the furnace and filling both chambers so that at all times and in all areas of both chambers the work in its passage of the cooling drum being heated by the hot work passing through said drum and as these heated gases pass over the work in the charging chamber of the furnace some of their heat is transmitted to the work, particularly in theregion of the charging end of the furnace chamber.

If desired, a portion of the gas may be bypassed to the work discharge chute to flll such chuteand prevent outside atmosphere from entering the chute when its discharge shutter is momentarily opened for the discharge -of the finished work. The pressure of the gas within such chute is' positive and is slightly higher than that .of the outside atmosphere, thereby affording a gase seal at this point.

In the accompanying drawings I have illustrated one embodiment of my invention which I have found highly satisfactory under conditions of actual commercial use.

In such drawings:

Fig. 1 is a top plan view of my apparatus.

Fig. 2 is a longitudinal section on the line 2--2, of Fig. 1.

Fig. 3 is a front elevation of Fig. 1

Fig. 4 is a vertical section on the line 4-4, of Fig. 2.

Fig. 5 is a rear elevation of the cooling drum assembly.

Fig. 6 is an enlarged fragmentary longitudinal section particularly showing the method of directly connecting the flanged discharge end of the rotating retort to the intake end of the cooling drum and the mounting of the drive sprocket on said flanged discharge end.

Fig. 7 is a fragmentary sectional detail on the line 1-1, of Fig. 5, particularly showing the cam plate and associated parts for automatically opening the shutter in the discharge chute at the work discharge end of the cooling drum,

Fig. 8 is a side elevation, partly broken away, at the work discharge end of the cooling drum, and

Figs. 9, 10 and 11 are fragmentary details further illustrating the quick acting shutter of the discharge chute and the mechanism for automatically opening and closing the same.

I have indicated generally at l a furnace unit and at 2 an axially alined cooling unit. Both units are suitably supported on frames F and F each unit being a complete assembly in itself.

The furnace unit includes a rugged shell 3 made of steel plate or the like. The heating chamber 4 is lined with any suitable high refractory 5 which is backed up with any suitable insulation 6. This chamber may be heated'in any suitable manner as by electricity, gas, etc.

As shown it is-heated by electricity, conventional heating elements being indicated at 1 in Fig. 2.

If desired, the heating'elements may be divided into separate zones (see Fig. 1) to assist in maintaining positive uniformity throughout the furnace chamber and any suitable automatic temnected at its discharge end with the adjacent end of the cooling unit so that the retort and cooling unit rotate in unison. The retort i is supported at its ends' on suitable trunnions l' rolling on taper roller bearings l0 mounted in any suitable supports [I carried by the frame F. The trunnion race at the discharge end of the retort is constructed as a pair of spaced annular flanges 9'. (see'Figs. 2 and 6) within which the roller bearings ID at this end of the retort closely track, and these flanges in conjunction with said roller bearings have the further function of preventing end play of the retort and coolingdrum during apparatus.

Integral with the retort and extending from end to end thereof is an internal spiral screw conveyor l2. Attached to the charging end of the retort isa loading drum l3 having a work intake opening 14. The work is continuously fed into the intake end of said drum by means of any suitable inclined trough or the like (not shown) and is picked up by the loading drum at each revolution thereof and fed through a pair of aligned charging slots IS in the drum and to deliver the work picked up within the drum to the registering charging slots I5 at each half revolution of the drum and retort, so as to ensure a continuous feedof the work to the spiral screw conveyor l2 of the retort. If desired, means,-such as adjustment screws, may be provided on the rear face of the drum for changing the dimension of the charging slots l5.

The conveyor I2 progresses the work continuously through the retort and into the adjacent end of the cooling unit 2. This unit consists of a drum, preferably of greater diameter than the diameter of. the retort and direct-connected thereto.

Fast to the cooling drum internally thereof is an internal spiralscrew conveyor II in axial prolongation of the screw conveyor I! of the retort.

The cooling drum is rotatably supported at its work discharge end by means of a trunnion 18 running on roller bearings is similar to the trunnion and roller bearing support of the retort.

At its work intake end the cooling drum is direct-connected to the discharge end of the rotor, preferably by means of an annular flange 20, at the discharge end of the retort which is bolted or otherwise fastened as at 2| to the adjacent apertured end plate 22 of the cooling drum (see Fig. 6).

The retort and. cooling drum are driven as a unit from any suitable drive source. As shown, the drive is from a motor M through a variable speed drive 23 and reduction unit 23' (Fig. '4), the driving sprocket of the reduction unit being operation of the I connected by a roller, chain 24 to a driven sprocket the cooling drum.

Additionally, the cooling drum assembly may be bolted to the furnace unit assembly by means of the rails R (see Fig. l).

The cooling drum is continuously water cooled by means of spray pipes 26 and 21 suitably supported exteriorly of the drum at any desired -locations. The water from these pipes washes the drum as it revolves therepast and drains into a tank 28 beneath the drum. The water in this tank is maintained at a level suillcient that the drum is partially immersed as it rotates therethrough.

At the discharge end of the cooling drum I bolt or otherwise attach as at 39' (Fig. 5) a work discharge chute 29 which rotates with the drum and is fitted at its discharge end with a quick opening and closing shutter 30 which is timed to the rotation of the drum and preferably opens once each revolution of the drum to discharge the finished work and instantly closes.

The inner end of the discharge chute projects through registering discharge slots 3| (see Fig. 8) in the adjacent end plate of the cooling drum and its trunnion I8, respectively, and in conjunction with the final turn of the spiral screw conveyor l1 forms a pocket 32 constituting the intake end of the discharge chute.

Just prior to the moment that the discharge chute in 'its rotation with the cooling drum reaches the down position shown in Figs. 5 and 8, the work discharge shutter 30 is automatically opened to discharge the finished work and instantly closed.

The mechanism for accomplishing the quick opening and closing of said shutter in time with the rotation of the cooling drum is detailed in Figs. 7 to 11, inclusive. Referring to these figures it will be noted that the shutter is spring-controlled and cam actuated and opens and closes by a right line sliding movement across the lower end of the discharge chute.

Adjustably mounted in any suitable manner on the supporting frame F for the cooling drum is also the center line of the discharge chute.

The leading cam surface 34 is adapted to be contacted once each revolution of the cooling drum and discharge chute by a cam follower 36 mounted on the short arm 31 of a crank lever 31-38. The crank-lever is pivoted at 39 to any suitable supporting bracket 40 carried by the chute. The long arm 38 of the crank lever is adjustably connected in anysuitable manner to the quick acting shutter 30. As shown this arm is provided with an elongated slot 4| receiving a roller 42 projecting from a cross bar 43 fixed to the outer surface of the shutter 39.

The marginal edges of the shutter are guided in a slideway 44 fastened to the underside of the discharge chute and this slideway is preferably laterally extended as at 45 (see Figs. 10 and 11) to constitute a support for the. shutter when to a bell crank 49 pivoted as at5ll to the slide-- way for the shutter 30.

Pinned to the edge of the bell crank 49 remote from the edge at which the spring 45 is anchored is one. end of a link 5|. The other end of said link is formed as an eye adapted to be assembled with an eye-bolt 52 fixed to the long arm 38 of the crank lever 31-38. When the cam follower 36 passes off the return surface 35 of the stationary cam plate 33, the tension on, the spring 46 is relieved and said spring closes the shutter by sliding it in reverse direction to its opening motion. 5

In order to assist in preventing escape of the gaseous or neutral atmosphere from the discharge chute during the opening movement of said shutter, I may pivot interiorly of the dis? charge chute an inclined sealing flap or clapper 54. Normally, this flap closes the discharge opening of the chute, the free edge of said flap being preferably upturned as at 55 and resting upon the inner surface of the shutter 30 'when said shutter is closed (see Fig. 11). So positioned, it relieves the shutter 39 of the weight of the finished work in the discharge chute as the discharge chute rotates towards its discharge position. When theshutter is opened the weight of the work resting on the flap 54 automatically swings said fiap about its pivot 53 into the dotted line position of Fig. 11. In its return motion, the adjacent edge of the shutter strikes the upturned edge 55 of said flap 54 andpushes the flap back'to its full line position of Fig. 11 within the discharge chute.

Any suitable artificial atmosphere as a gaseous or neutral atmosphere may be continuously supplied to and maintained within the cooling drum and furnace unit. Where a gaseous atmosphere is supplied it may be introduced under pressure at the work discharge end of the cooling drum in counter fiow relation to the direction of feed of the work from any suitable gas cracking unit,

not shown. 3 Referring to Fig. 8 I have indicated at 55 a supply connection for the artificial atmosphere. The supply 56 has an elbow connection at 51 with an axial pipe 58 which rotates with the cooling drum, being supported and braced by means of any suitable support 59 attached to the adjacent end. of the cooling drum. The axial pipe 58 has an offset discharge pipe 60 entering the cooling drum. The axial pipe 58 is journaled at one end in a bearing 6| on the cooling drum and at its other end rotates in a swivel joint 52.

If desired a portion of the artificial atmosphere may be by-passed to the discharge chute 29 by means of the by-pass connection 63. Theatmosphere thus by-passed into the discharge chute 39 acts as a pressure seal to assist in preventing loss of the atmosphere through the work discharge and of the tube 29 when the shutter 30 is opened by excluding the entrance of outside air into the, discharge chute.

The artificial atmosphere is continuously circulated over the work contained in said drum g and in the retort, filling the drum and retort.

The action is in the nature of a regenerative action, in that the gas discharging into the cool end of the cooling chamber absorbs some of the heat of the work in said'chamber and as it passes toward the heating chamber of the furnace delivers its heat to the work within said heating chamber, thereby augmenting to some extent the heatingaction. The gas vents'at the charging end of the furnace. The design of the loading drum, however, is such that undue lose! the artificial atmosphere is prevented. Thus during its progress from end to end of the apparatus, the work is continuously subjected to the protective action of the gaseous atmosphere. This action is con stant at all times and in all areas of the appa-' of work are placed in the intake end of the screw conveyor I2 at each complete revolution of said conveyor and a single charge is discharged at each complete revolution of the cooling drum, such arrangement is optional and may be changed as desired.

The temperature of the .work discharged will vary with,the temperature of the retort, the volume and temperature of the cooling water, and the speed of rotatiomof the drum. These are all variable factors which may be regulated at will.

Various other modifications in machine and method may obviously be made, depending upon the nature of the work being treated and the wanted characteristics in the finished work.

- What I therefore claim and desire to secure by Letters Patent is:

1. Apparatus for continuously heating and cooling ferrous and non-ferrous metals, compris,

- ing a furnace having a heating chamber, means for heating said chamber, a retort rotatably mounted within said chamber and extending from end to end thereof, a spiral screw conveyor fast to said. retort internally thereof, a cooling drum'rotatably mounted at the discharge end of said retort and direct-connected thereto to rotate in unison therewith, a spiral screw conveyor fast to said drum internally thereof and disposed in axial prolongation of said first-named conveyor,

means for cooling said drum, means for imparting continuous rotation to said retort and drum,

a discharge chute fast to the discharge end of said cooling drum to rotate therewith, a shutter at the discharge end of said chute, and means for automatically opening and closing said shutter in timed relation to the rotation of said drum. 2. In combination, a furnace having a heatin chamber, a retort rotatable in said chamber,

work feed means internally of said retort and rotating therewith, a cooling drum aligned with said retort and direct-connected thereto to ro- "tate in unison therewith, work feed means internally of said drumand rotating therewith for progressing the work fed thereto from said retort tot-he discharge end of said drum, a work discharge .chute at' the discharge end of said cooling drum and rotating therewith, and having an automatically opening and closing work discharge shutter, a supply pipe rotatably mounted on the discharge end of said drum and having an inlet leading into said drum for introducing artificial atmosphere under pressure into said drum in counter-flow to the direction of the feed of the work, and a bypass from said supply pipe delivering to said discharge chute adjacent the shutter thereof.

3. In combination, a furnace having a rotatable retort, a cooling drum aligned with and direct-connected to said retort to rotate in unison therewith, means for continuously feeding work through said retort and drum, a work discharge chute rotating with said drum at the discharge end thereof, an automatic shutter at the discharge end of said. chute, and means timed to the rotation of said drum for automatically opening and closing said shutter.

4. The combination of claim 3, and, an inclined flap pivoted interiorly of the chute above the shutter with-its free edge resting on the shutter to open automatically with the pressure of the work when the shutter is opened and to be restored automatically to normal position by the shutter when the shutter is closed.

5. 'I'hecombination of claim 3, the means for automatically opening and closing said shutter comprising 'a stationary cam plate having spaced shutter opening and closing cam surfaces, a pivoted crank lever having one arm connected to said shutter and another arm provided with a cam roll for initial coaction with the shutteropening cam surface of said plate to open said shutter and for subsequent coaction with the shutter closing cam surface of said plate to close said shutter, a bell crank pivoted adjacent said shutter, a spring connected at one end to said chute and at its opposite end to said bell crank,

and a link fastened at one end to said bell crank and at its other end to the second-named arm of said crank lever to close said shutter when the cam roll in its continued movement over 'end of said drum and rotating therewith, said chute having its inner end extending, into the drum and in conjunction with the final turn of said spiral screw conveyor forming a. pocket for directing the treated work into said chute, an automatically opening and closing work discharge shutter at the discharge end of said chute, and means for positively opening and closing said shutter in timed relation to the rotation of said KRISTIAN A. JUTI-IE

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