US2046921A - Method of and apparatus for pack annealing - Google Patents

Description

July 7, 1936.

E. w. MIKAELSON ET AL ,046,921

METHOD OF AND APPAliATUS FOR PACK ANNEALING Filed 061;. 4, 1933 A s Sheets-Sheet 1 v l 2 w 6 2 July 7, 1936,

E. .w. MIKAELSON ET AL METHOD OF AND APPARATUS FOR PACK ANNEALING Filed Oct. 4, 1955 3 Sheets-Sheet 2 July 7, 1936.

E. W. MIKAELSON ET AL METHOD OF AND APPARATUS FOR PACK ANNEALING Filed Oct. 4, 1933 :5 Sheet s-Sheet s Patented July 7, 1936 UNITED STATES PATENT OFFICE PACK ANN METHOD OF AND APPARATUS FOR EALING tion of Pennsylvania Application October 4, 1933, Serial No. 692,198

10 Claims. (Cl. 80-42) This invention relates to methods of and apparatus for pack annealing.

Various types of mechanisms for use in the pack annealing of spring flats or other products of rolling mills have heretofore been designed or suggested, these mechanisms being commonly designated cooling beds" in the industry. In carrying out the process of pack annealing, bars which are generally flat and relam tively so thin that they are unable to stand on edge without lateral support are delivered rapidly one after the other in highly heated condition from a rolling mill to an apparatus which deposits them successively onto one end of a u cooling bed, the bars being maintained erect upon the bed by some backing means until a substantial pack has been formed. In the completed pack the fiat sides of each bar bear closely, respectively, against the flat sides of the adjacent bars so that air is substantially excluded, the rate of cooling greatly retarded, and the formation of scale largely prevented. It will be understood that as each successive bar is added to one end of the pack, the entire pack is as advanced a distance equal to the width of the added bar, and eventually the bar first positioned reaches the opposite end of the bed and thereafter passes onto a conveyor or bar collecting means, successive bars likewise passing off of the cooling bed as freshly rolled bars are added to the opposite side. As the bars come from the rolling mill, they are very highly heated and it is a function of the cooling bed just described to procure gradual and uniform cooling of each bar as it traverses the bed so that the bars as delivered from the apparatus are of substantially uniform temperature from end to end and have been sufficiently cooled to permit further operations to be performed upon them.

The present invention contemplates an improved method of and apparatus for effecting uniform cooling of the bars as they pass over the bed in pack formation. It includes means for 45 applying heat to those members of the cooling bed, generally designated skids, upon which the bars rest while they are in pack formation, and for so regulating the amount of heat transmitted to these members that the temperature 50 of each is substantially that of the temperature of the bars resting upon the same. In this manner the formation of cold spots on the several bars at the points where they contact with the supporting skids is prevented since it is not pos- 55 sible with such a construction for the supporting bars or skids to withdraw heat from the bars and radiate it to the surrounding atmosphere.

The invention contemplates the provision of additional means for regulating and safeguarding the cooling process, the pack of bars undergoing cooling being protected by shields located above, below, and to the sides of the same which prevent drafts of air from contacting directly with the pack and likewise insure uniform rates of cooling for all horizontal areas thereof.

Other novel features are provided for facilitating the formation of the pack and advancement of the pack across the cooling bed, which features will be hereinafter pointed out and specifically claimed.

Naturally the invention may have various embodiments, and that form which is set forth herein for the purpose of disclosure is given by way of example only.

In the drawings:

Figure 1 is a top plan view of the cooling bed including the bar feeding mechanism and a portion of the delivery table;

Figure 2 is an end elevation of the same, partly broken away; 2 Figure 3 is a section on line 3-3 of Figure 1; Figure 4 is a section on line of Figure l on a slightly larger scale; and

Figure 5 is a section through a portion of the pack forming mechanism.

Referring first to Figure 1. A portion of the bar delivery mechanism, which transfers the heated and freshly rolled bars from the rolling mill to the cooling bed, is indicated generally at Ill. The bar receiving and pack forming mechanism is indicated at H and the cooling bed proper at l2. A bar is indicated at I3 (Figure 2), this bar being relatively wide and thin and moving in the direction of the arrow A from the delivery mechanism or feed table onto the pack forming mechanism, feed rolls being indicated at H for passing this bar onto the pack forming mechanism at the desired linear velocity. Successive bars are rapidly delivered in this manner in the continuation of the operation of the mill and cooling bed, as will be understood.

From the feed rolls M the bar passes into a trough defined by a side guard E5, the vertically extending portions ll of the spaced lifting and turning levers l8, and the upper surface of the longitudinally extending support i6 upon which support the guard [15 is rigidly mounted. The longitudinal support has two spaced recesses in its upper surface to receive the normally horizontally extending bar engaging and lifting portions I 9 of members 18, the upper surfaces of these members lying flush with the upper surface of supporting table I6. The two lifting and turning levers iii are fixed upon a rock shaft 20 which is adapted to be rotated through an angle of substantially 90, from the position in which it is shown in full lines in Figure 3 to its dotted line position, this rocking movement taking place after a small stack of bars, indicated at S, has been formed in the trough just referred to, this movement causing deposition of these bars on the adjacent edge of the cooling bed in the form of a small pack, as indicated at S (Figure 3). The mechanism for rocking the shaft 20 may be of any conventional type, and it will be understood, of course, that after the pack S has been deposited upon the edge of the cooling bed, members l8 are retracted to original position, after which a further series of bars is stacked up in the trough above lifting arms l9.

Prior, however, to the return of the lifting and turning levers I8 to full line position (Figure 3), the pusher bars 25, of which there are three, are advanced to engage the small pack S and to advance the same a suflicient distance onto the cooling bed to enable the latching devices 2| to engage the upper rear corner of the pack, as shown in Figure 3, and to prevent the bars from falling rearwardly. The bars are prevented from overturning or falling forwardly by reason of the fact that the cooling bed upon which the bars rest is upwardly inclined from left to right (Figure 3). Any suitable mechanism may be provided for advancing and retracting the pushers 25 with their pusher heads 26. This mechanism may conveniently comprise rack teeth 21 secured to or integral with the pushers, which teeth are engaged by pinions fixed upon shaft 28, which shaft may be in turn rotated in either direction by motor 29 acting through gearing 30.

The cooling bed includes a plurality of skid bars, in the embodiment shown there being three of these bars, indicated at 35, each such bar being upwardly inclined from left to right (Figure 3) and supported upon the spaced upper edges of a channel-shaped member 36 of refractory material, which member is in turn supported in a trough-like recess formed in longitudinal standards or supports 31. Under each of the skid bars are three heating elements which are indicated generally at 38, 39, and 40, these heating elements being preferably electrical re sistance elements connected to any suitable source of current supply by means of cables ll, 42, and 43, respectively, which pass downwardly through suitable apertures formed in the bottom of the refractory lining member 36. It is the function of these heating elements to supply the skids located immediately above the same with sufiicient heat to maintain the temperature of each skid substantially the same as that of the pack of bars located above it so that the skids have no tendency to withdraw heat from the bars at those points where the skids and bars are in contact and thus to form cold spots and interfere with uniform cooling of the bars. Naturally the temperature of the bars in the pack falls as they advance over the cooling bed, and hence less heat should be supplied to those portions of the skids adjacent the delivery end of the cooling bed than is supplied to those portions of the three skids adjacent the pack forming end of the bed,

In the operation of the cooling bed, therefore,

the heating element 38 will be the hottest and the heating element 4|] the coolest of the three heating elements. These heating elements may be formed in various ways, and the amount of heat which each delivers to the skid bar portion above it may be either manually or automatically controlled as desired. A greater number than three heating elements may be employed if it is desired to more closely regulate the temperature of the skid bars at various points along the length thereof. Furthermore, it is possible to use heating elements which do not consume electricity but which, for instance, consume gas, where gas is available. The bars issuing from the pack, one of which is indicated at S, slide in succession downwardly into a piling cradle 44 from which they are removed from time to time as a stack of desired size is accumulated. The refractory lining members 36 serve not only as supports for the metallic skids 35 but as protective shields for the standards 31, protecting these members against excessive heating and directing the heat delivered by the heating elements to the skids themselves, where it is required.

it has been found that, in some installations, drafts of air passing over the cooling bed extract more heat from some portions of the bed than from other portions and that, iurthermoi'e, heat may be too rapidly radiated from the bars even in the absence of drafts, as for instance in cold weather. Shields may therefore be provided for protecting the pack against direct radiation of heat to the atmosphere except at the pack forming and delivery ends or the cooling bed. Thus a roof structure of refractory brick or the like is indicated at 50, this roof structure being supported upon a suitable frame, for instance, one including the I-beams illustrated, and serving to prevent the direct upward radiation of heat from the pack as well as preventing drafts of air from passing downwardly onto the pack. For similar reasons side walls 5| may be provided wherever thought necessary or desirable and likewise a bottom 52, comprising panels supported upon the elongated supports 31, so that the skid bars 35 are in reality positioned in a chamber which is completely closed to the atmosphere save at its ends. It is not necessary in all installations to completely cover the pack in the manner just described, but in the average case it will be found that the process of cooling is rendered more uniform by enclosing the pack in a chamber such as illustrated.

By the careful regulation and control of the heating elements associated with the skids, each of these members may be caused to have, at each point along its length, a temperature which very closely corresponds to the temperature of the bars directly above and contacting with the same. As a result the skids will not extract heat from the bars, thus causing cold spots, and the bars discharged from the bed will be uniform in temperature from end to end.

The apparatus is so constructed that it will freely handle without adjustment bars which vary considerably in width. The latches 2| are fixed upon the lower ends of rods 2| slidably retained within vertically disposed apertures formed in bracket members mounted on the frame. Collars 2| fixed on these rods limit the downward sliding movements of the rods, but latches 2| may move downwardly sufficiently far to engage the narrowest bars which the machine is expected to handle. For the convenience of the operator, means is provided for lifting the latches 2|. this means including arms 2| each having a pin and slot connection with the associated rod 2|, the rock shaft 2i upon which these arms are fixed, and a hand lever 2| for rocking the shaft and arms and hence drawing upwardly the rods 2i and latches 211. Because of the pin and slot connections between the arms 2i and rods 21', the lifting mechanism does not interfere in any manner with the ordinary rising and falling movements of the latches.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a. cooling bed for pack annealing, in combination, a bed section having a bar supporting skid, a plurality of heat generating units positioned along said skid in position to supply heat to the same, and means for individually controlling the amount of heat developed by said units.

2. In a cooling bed for pack annealing, in combination; an elongated member of refractory material having an upwardly opening recess formed therein, a heating element positioned in said recess, and a skid positioned to close the mouth of the recess and receive heat from the heating element.

3. In a cooling bed for pack annealing, in combination, an elongated member of refractory material having an elongated upwardly opening recess therein, a plurality of heating elements positioned in said recess and arranged in series from end to end thereof, means for separately controlling the action of said elements, and an elongated metallic skid positioned to close the mouth of said recess and to be heated by said elements.

4. In a cooling bed for pack annealing, in combination, a bed section having a bar supporting skid, means for heating said skid to different degrees of temperature at various points along its length, and means for feeding highly heated bars onto said skid at one end thereof to form a pack and thereafter intermittently advancing the pack toward the opposite end of the skid.

5. In a cooling bed, in combination, a bed section having parallel skids for supporting bars to be cooled, and means other than the bars 5 being cooled for heating said skids.

6. In a cooling bed, in combination, a bed section having portions for supporting bars to be cooled, and means other than the bars being cooled for heating said bar supporting portions, for preventing the formation of cold spots in such bars during cooling.

7. In a cooling bed, in combination, a bed section having a skid for supporting bars to be cooled, and means other than the bars being cooled for heating said skid to varying degrees of temperature at various points along the length thereof.

8. In combination, an open-ended but otherwise closed chamber, bar supporting members in said chamber, and means other than the bars being cooled for heating said members.

9. The method of pack annealing which comprises passing heated bars over supporting means in pack formation and maintaining each bar substantially uniform in temperature from end to end during its passage through the pack by supplying sufficient heat from an external source to those portions of said means with which the bar contacts to prevent the flow of heat from the bar to the support, and hence preventing the formation of cold spots in the cooling bar.

10. The method of gradually cooling heated bars which comprises passing the bars over supporting means located in a substantially closed chamber, and maintaining each bar substantially uniform in temperature from end to end during such passage by supplying sumcient heat from a source other than the bar to those portions of the supporting means with which the bar contacts to prevent the flow of heat from the bar to the support and hence preventing the formation of cold spots in the cooling bar.

ERIK W. MIKAELSON.

ALEXANDER K. HAL/ELTON.

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