US2721734A - Multiple-unit annealing furnaces - Google Patents

Description

Filed Dec. lO, 1952 H. GRNEWALD ETAL MULTIPLE UNIT ANNEALING FURNACES 5 Sheets-Sheet l Oct. 25, 1955 H. GRUNEWALD ET AL 2,721,734

MULTIPLE UNIT ANNEALING FURNACES Filed DGO. lO, 1952 3 Sheets-Sheek 2 3f Hw Oct 25, 1955 H. GRUNEWALD ET AL 2,721,734

MULTIPLE UNIT ANNEALING FURNACES Filed Dec. l0, 1952 5 Sheets-Sheet I5 @venia/s Hs/NR/c# GRy/vswmn HEL/wr GRuNsN/MD WMDs/wak GRUA/@Amo Arrow/Er www United States Patent O MULTIPLE-UNIT ANNEALING FURN ACES Heinrich Grnewald, Helmut Grnewald, and Waldemar Grnewald, Hilchenbach, Westphalia, Germany VApplication December 10, 1952, Serial No. 325,066 Claims priority, application Germany December 19, 1951 Claims. (Cl. 263-36) This invention relates to an annealing furnace of the kind in which the charge is compiled upon a base and treated under, or within, a protective shell which, during the heat treatment, is covered by a heating cover and during the time of cooling by a cooling cover. The invention, more particularly, refers to that type of annealing furnace in which a plurality of furnace bases, or units, is arranged in a circle to be served consecutively by the aforesaid heating and cooling covers.

A furnace of the aforesaid type is known in which the furnace units are arranged to be served with the charge by the arms of a revolving conveyer or carrier. The carrier whose arms carry the charge, is raised and lowered-by hydraulic means, but advanced in a horizontal direction by separate mechanical means. The furnace units are suspended from a strong frame, while the arms of the carrier are comparatively weak. In the progressive operation of this furnace the charge, at each step from one unit to the other, must be introduced into the units from below through small openings in the bottoms thereof which, in the case of small parts, is practically impossible. The charge, also, becomes subjected to the atmosphere during each step, which is exceedingly detrimental. I

The invention, therefore, has its main object 'in the 'provision of an annealing furnace of the kind referred to in which the aforesaid disadvantages are eliminated and in which, partly owing to the removal of these obstacles, a greater output can be obtainedwithin a shorter time and at an appreciably reduced consumption of energy.

Another object of the invention consists in an improved arrangement of the furnace bases, or units, in a manner in which they can more readily be served by the heating and cooling covers in a denite working sequence in order to enable the aforesaid economy in time and energy.

A further object of the invention rests in the provision of combined raising, advancing, and lowering means for the said heating and cooling covers which enable a simple and convenient manner of moving the said covers in their proper working sequence from one unit, or groups of units, to the other.

With these and other objects in view the invention consists in the provision and arrangement of an annealing furnace of the said type, in which a plurality of furnace bases, or units, is arranged in sequential order in a closed formation, preferably in a circle, and of which a predetermined adjacent number, four for instance, is associated to be served in their working sequence by one heating and one cooling cover respectively. The arrangement according to the invention is such, that the said covers are carried on a revolving carrier, on which they are movable in a vertical direction and, in dependence therefrom, also in a horizontal direction from one unit to the other.

In a preferred form of the invention the transporting device consists, in cooperation with its associated numberof adjacent furnace bases, or units, of ,anarrangement'of cross beams and of means for impartingto the ICC said cross beams rotary and vertical movements, and in which one arm of the cross carries the heating covers, while the other arm supports the cooling covers.

Other features and advantages of the invention will be apparent from the following description of the accompanying drawings, which diagrammatically represents the invention by way of example, and in which:

Fig. l is a part-sectional side elevation of an arrangement according to the invention with the heating and cooling covers in their raised position.

Fig. 2 is a similar view showing the cooling covers lowered down on the furnace units.

Fig. 3 illustrates the arrangement in plan view.

In Fig. l the carrier is shown in its raised position with the heating covers above the furnace bases, or units. These are illustrated on the left hand side of the figure with the inner shell in side elevation and on the right hand side in a vertical section therethrough.

The carrier comprises a column 3 to which is ailixed a horizontal beam 4 from the ends of which the heating covers 1 are suspended. Each unit is provided with a star-like support 5 for both the inner shell 2 and the heating covers, and in which the inner pillars 5a serve as a rest for the inner shell, while the covers 1, When lowered, are seated on the outer pillars 5b.

In order to prevent the heating covers, when in their lowered position, to waste heat by downward radiation, the bottoms 6 of the inner shells 2 are encircled by sand trays 7 of substantially U-shaped cross section, into which downwardly projecting rims 8 of the said covers 1 are seated and thereby seal the interior of the covers against the entrance of atmospheric air.

On the bottom 6 of each heating unit is also provided a heat insulating chest 9 which preventsV the downward radiation of the heat from within the inner shell 2. On the top of this chest 9 a ring 10 is arranged, which is provided with upstanding ribs onwhich the charge 11 is built up. A ventilator 12 in the free centre space of the ring is driven by a motor 13 and serves to agitate the hot gases in the interior of the shell. A preferably resilient packing 14 is provided to effect a gas-tight closure of the inner shell at its bottom 6 A telescopic tube 15 is provided on the column 3 through which the combustible gas is fed into the heating covers 1. From this tube 15 the gas passes through a connecting socket 17 into a hollow in the centre of the cross beam 4 and thence through a branched pipe 18, which is rotatable with the cross head, downwardly into the interior of the covers 1. This arrangement has the great advantage in that it avoids having to connect and disconnect the gas conduits with every new charge of the furnace.

The column 3 of the carrier, which latter may be hydraulic or mechanical, moves in a cylinder 19 in which a number of vertical slots 20 is arranged corresponding to the number of units to be served, i. e. eight in the present instant. The heating covers are provided with projecting arms having guide pins or rollers 22 at their ends with which they are adapted to move in the slots 20.

When the rising covers 1 approach their upper end positions, the rollers 22 are diverted into the inclined tracks 23 of the slots 20 and thereby to turn the cross head together with its heating and cooling covers through about one half of its angle of advance, which angle, in the case of eight units would be 22 to 23 approximately. When the rollers 22 have reached their upper positions on the inclined slot tracks, the pump which serves to raise the entire cross head with its attached covers 1 and 25 is automatically set to rest, which may be .done in any convenient manner and by any known means. Thereupon the rollers 22 enter the downwardly inclined parts 23a of the branches 23 and the' cross head'with its heating and cooling covers moves down the adjacent slots 19 into its new position. If the carrier is moved mechanically, the reversal of the driving motor will be controlled in a similar manner.

Fig. 2 .illustrates the arrangement similar lto Fig. l in a `section through the central cylinder andthe cooling covers 2S, however, with the unit on the left hand side of the ligure being shown in elevation. The cooling covers 25 are suspended at the ends of their cross beam 24 `which is arranged at right angles to the aforedescribed beam 4.

In addition to the guide slots 22, 23, 23a the central cylinder `19 is vprovided with electric connection means 27 which are only diagrammatically indicated in the drawing as positioned at the top of the cylinder in Fig. 2. When the cross head 4, 24 is being lowered, these connection means enter into engagement with contact fingers 28 `on the cross beam 24 and thereby close a circuit to the ventilators-26 for example-of the cooling covers, and in the case of a gas heating furnace, also for the heating vcovers for blowing the air necessary for combustion into the said heating covers. In electric furnaces no ventilators are required in the heating covers and the respective contacts 27, 28 then serve for connecting and disconnecting the electric heating resistances in the covers 1. It is thus not necessary to make the electric contacts movable, as is the case at present, because of the current being cut on and oif automatically with the raising and lowering of the cross head 4, 24 as described.

The mode of operation of the new furnace arrangement will best be described with reference to Fig. 3 of the drawings. In this figure eight units are shown to be positioned in a closed circle. The beam 4 of the cross head of the carrier is arranged to carry two heating covers 1 depending therefrom, while two cooling covers 25 are suspended at the ends of the beam 24.

The units at a in Fig. 3 are shown to be in their heating positions with the heating covers lowered on them. Assuming now the equipment to be operated in clockwise direction, the units at b are uncovered and are thereby in a state of natural cooling, while the units in position c are covered by the cooling covers 25 in which they are subjected to forced cooling. In the position d the inner shells have been taken olf and the finished charge removed from the bases 6. After the untis in position d have been provided with fresh charges the previously raised heating covers 1 are now lowered over the units at d and sealed gas-tight.

When the annealing process in the units at a has been finished the cross head 4, 24 is raised, turned about 45 in the clockwise sense of rotation, and then lowered again. The heating covers thus take their positions on the units at d and the cooling covers on the units at b. After the expiration of the new annealing period, which may last about 6 to 8 hours according to the weight of the charge, the aforesaid procedure is repeated as often as required.

The invention is not intended to be limited to the arrangement shown and described but may be modified to suit requirements or convenience without thereby departing from the spirit of the invention as laid down in the following claims.

What we claim is:

l. An annealing furnace, comprising, a plurality of stationary heating units arranged in closed formation, a heating cover and a cooling cover, a transporting device, a revoluble carrier in said transporting device for supporting said covers in downwardly depending positions, means for raising and lowering said carrier, means for imparting intermittent rotary movement to said carrier, a telescopic gas conduit in connection with said carrier, a gas distributing chamber in said carrier, and gas pipes betweensaid chamber and said heating covers for admitting combustible gas'into said heating cover.

2..An annealing furnace, comprising, a plurality of stationaryheating units arranged in closed formation, a plurality of heating covers and a plurality of cooling covers, a transporting device, a column in said transporting device, a cross head on said column for dependingly supporting said heating and cooling covers, means for raising and lowering said column and cross head, means in dependence of said raising and lowering means for horizontally advancing said cross head and covers over said heating units, a telescopic vertical gas conduit in connection with said column, a gas distributing chamber centrally disposed in said cross head and in connection with said telescopic gas conduit, and gas pipes movable with said cross head for connecting said gas distributing chamber with said heating covers.

3. In an annealing furnace, a plurality of stationary heating units arranged in a circle, heating and cooling covers for cooperation with said heating units, a transporting device, a revoluble cross head in said transporting device for carrying said heating and cooling covers, means for raising and lowering said cross head and covers, and a'star-like support having inner and outer seating means, said inner seating means serving for supporting said heatingunits and said outer seating means for supporting said heating covers when lowered over said heating units.

4. In an annealing furnace, `a plurality of stationary heating units arranged in a circle, heating and cooling covers for cooperation with said heating units, a transporting device, a revoluble cross head in said transporting device for carrying said heating and cooling covers, means vfor .raising and lowering said cross head and covers, means in dependence of said raising and lowering means for imparting intermittent rotation to said cross head and covers when in their raised position, a star-like support for each of said heating units, a ring of inner and outer pillars in each of said star-like supports, said inner pillars serving for supporting said heating units and said outer pillars for seating said heating covers when in position on said heating units, and means for preventing the escape of heat from said units and covers when in position on said supports.

5. In an annealing furnace, a plurality of stationary heating units arranged in a circle, a removable inner shell for covering each of said heating units while at work, heating and cooling covers for cooperation in their respective working sequence with said heating units, a transporting device for said covers, means in said transporting device for-carrying and moving said covers vertically and horizontally in relation to said heating units, spaced inner and outer seats in a support for seating said inner shell and said heating covers respectively, an insulating chest at the bottom of each inner shell, a ring having upstanding ribs on said chest for the reception of the charge to be treated, a free central space in said ring, agitating means in said central space for agitating the hot gases in said inner shell, and driving means below the said insulating chest for driving said agitating means.

6. An annealing furnace having a number of furnace units arranged in a circle and turnable and vertically movable-means for cooperation with said furnace units in the treatment of the charges therein, comprising a number of mutually independent supports for said furnace units, a central standard having guide means preferably on its outer face, a carrier movable in said standard, a cross head at the upper end of said carrier, a number of arms to constitute said cross head, open-bottomed covers suspended from the ends of said arms to tit over the said furnace units when lowered, and means in connection with said cross head for controlling the conveyance of a charge heating medium to the said covers.

7. An annealing furnace having a number of furnace units arranged in a circle and both turnable and vertically movable means for Vcooperation with said furnace units in th'e`tre'a'tm'ent of 'the charges therein, said annealing furnace comprising, a number of mutually independent supports for the said furnace units, a substantially cylindrical standard disposed concentrically to the circle of furnace units, a vertically movable column in said standard, preferably hydraulic means for raising and lowering said column, a cross head at the upper end of said column comprising four arms disposed at right angles to each other, open-bottomed covers depending from the ends of said arms, vertical guide slots on the outer face of said cylindrical standard, arcuate slots joining said vertical slots at their upper ends, and guide members on said covers movable in said slots for guiding said column and said covers vertically up and down and in dependence of the said vertical movement in a substantially horizontal movement from one unit to the other.

8. An annealing furnace having a number of furnace units arranged in a circle and both turnable and vertically movable means for cooperation with said furnace units in the treatment of the charges therein, said annealing furnace comprising a number of mutually independent supports for said furnace units, an upright cylinder substantially coaxial with said circle of furnace units, a vertical carrier movable in the said cylinder, a cross head comprising two mutually crossing arms at the top of said carrier, open-bottomed heating covers depending from the ends of one of the said arms, open-bottomed cooling covers depending from the ends of the other of said arms, spaced vertical guides on said upright cylinder, arcuate guides to connect the upper ends of adjacent vertical guides, means for raising and lowering said carrier and cross head, and means cooperating with said guides in connection with said heating covers for controlling both the vertical and the advancing movements of said covers onto and off the said furnace units and in a substantially horizontal direction from one furnace unit to the other.

9. An annealing furnace having a number of furnace units arranged in a circle and means for cooperating with the said furnace units for the treatment of the charges therein, said annealing furnace comprising, an upright cylinder coaxial with the said circle of furnace units, a vertical carrier movable in said cylinder, means for raising and lowering the said carrier, a cross head comprising mutually crossing arms at the top of said carrier, open-bottomed heating and cooling covers depending from the ends of said arms, vertical guides on said cylinder, arcuate guides also on said cylinder to connect the upper ends of adjacent vertical guides, means cooperating with said guides in connection with said heating covers for controlling both the vertical and the substantially horizontal movement of said covers with respect to said furnace units, a gas distributing chamber centrally disposed in said cross head, means to supply gas to said gas distributing chamber, and gas pipes movable with the said cross head for connecting said gas distributing chamber with said heating covers.

10. In an annealing furnace having a plurality of stationary furnace units arranged in a circle, an upright cylinder coaxial with the said circle of furnace units, a carrier movable in said cylinder, a cross head at the top of said carrier, radially extending arms on the said cross head, open-bottomed heating and cooling covers depending from the said arms, means for raising and lowering said carrier, means for advancing said carrier with said depending covers moving from one furnace unit to the other in dependence of its rising and lowering movements, and a star-like support for each of said furnace units having inner seating means for supporting said furnace units and outer seating means for supporting said heating covers when in position over the said furnace units.

References Cited in the le of this patent UNITED STATES PATENTS 446,532 Maxim Feb. 17, 1891 1,467,670 Josephs, Jr. et al. Sept. 1l, 1923 2,418,983 Palmer Apr. 15, 1947 2,600,094 Cone June l0, 1952

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