US2779584A

US2779584A - Strip cooling tower

Info

Publication number: US2779584A
Application number: US187169A
Authority: US
Inventors: Torsten F A Edvar
Original assignee: Selas Corp of America
Current assignee: Selas Corp of America
Priority date: 1950-09-28
Filing date: 1950-09-28
Publication date: 1957-01-29
Anticipated expiration: 1974-01-29

Description

Jan. 29, 1957 T. F. A. EDVAR STRIP COOLING TOWER Filed Sept. 28, 1950 3 Sheeis-Sheefc 1 INVENTOR. TORSTEN F. A. EDVAR ATTORNEY.

Jan. 29, 1957 T. F. A. EDVAR 2,779,584

STRIP COOLING TOWER Filed Sept. 28, 1950 3 Sheets-Sheet 2 INVENTOR. TORSTEN F. A. EDVAR ATTORNEY Jan. 29, 1957 T. F. A. EDVAR STRIP COOLING TOWER Filed Sept. 28, 1950 3 Sheets-Sheet 3 ATTORNEY.

United States Patent The present invention relates to apparatus for treating metal, and more particularly to the construction of a cooling tower for strip metal and the structure upon and by which the guide rolls for the strip moving through the tower are mounted, as well as the construction of the cooling ducts.

In the continuous annealing of strip metal such as cold rolled steel, for example, "there is. provided a furnace through which the strip is pulled while it is being brought up to annealing temperature. As the strip leaves the furnace it passes through a suitable seal directly into a cooling tower where controlled cooling takes place until it is below a temperature at which lit will oxidize in the atmosphere.

Coolingtowers can take many forms. One of the most usual, however, is one in which the strip is pulled through a series of vertical, parallel ducts that are joined at their upper and lowerends with adjacent duets. At the point of juncture between adjacent ducts there is provided a guide roll around which the strip passes in a reverse bend from oneduct to the next. Provision must be made for threading the strip over the rolls in a series of loops, and provision must also be made for changing the rolls from time to time. This latter operation, with constructions heretofore available has been difiicult to accomplish, particularly with the upper rolls that may be as much as fifty feet above floor level.

According to the present invention there is provided a cooling tower comprising a plurality of parallel duets through which the strip moves as it is being cooled :from annealing temperature to a temperature slightly above atmospheric; The guide rolls at each end of adjacent ducts are mounted for rotation in a special chamber that can be moved as -a unit to a convenient location for removal of the roll contained therein. Meansis provided between each chamber and the ducts communicating therewith to form a pressure-tight seal so that some .desired atmosphere may be. maintained within the cooling tower. These seals are so constructed that expansion and contraction of the ducts can take place without break.- ingthe seal.

Each of the roll chambers is so formed that the roll is mounted therein in sealed bearings so that .the atmosphere in the cooling tower will .not be lost andsothat infiltrationof air cannot take place.

One .wall of each chamber maybe removedso that accessmay be had to the ducts for .thepurpose of threading the strip over the rolls.

It is an object of the invention to provide a cooling tower for strip material through which the strip may easily be threaded. It is a further object of the invention to provide a cooling tower in which the guide rolls for the strip may easily be removed and replaced with a minimum of time and effort.

It is a more specific object of the invention to provide roll chambers at the ends of the ducts of acooling tower than can be removed individually. A further object of the invention is to provide sealing means between the ducts of a cooling tower and :roll chambers at the ends thereof which is gas tight and which will permit a relatively large expansion and contraction of the duets without breaking the seal.

A further object of the invention is ,to provide a cooling tower in which each of the ducts is independently mounted. The ducts are suspended 'at their upper ends 2,779,584 Patented Jan. 29,

only so that each duct may be free to expand and con tract without interference with other portions of the cooling tower.

The various features of novelty which characterize my invention are pointed out with particularity inthe claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, refer.- ence should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

Figure 1 is an end View of a portion of the cooling tower taken on line 1-.-.-1 of Figure 2;

Figure 2 is a side View of a portion of the cooling tower taken from the right of Figure 1;

Figure 3 is a section through the roll chambers and the ducts as talren on line 33 of Figure 1;

Figure 4 is a section view of one end of one of the upper roll chambers taken on line 4-4 of Figure 2; and

Figure 5 is a section of a portion of one of the lower,

roll chambers taken on line 5-5 of Figure 2.

In the continuous annealing of strip material the strip is drawn through a furnace in which it is heated to the annealing temperature. As the strip leaves the furnace it is moved in a series of ,convolutions through a cooling tower. The number of convolutions or passes of the strip, or the number of ducts that are required. in the cooling tower will depend upon the speed of the strip, its temperature th temperature to which it is to be cooled. have as many or as few ductsas is desired.

Referring to Figures 1 and 2 there is shown a portion of acooling tower through which the strip is pulled after it has been heated'in a furnace of some type that is capable of heating the strip to an annealing temperature for example. .As shown herein, there are provided vertical columns 1 and upper horizontal beams 2 attached to the upper ends of the columns. There are also provided llower horizontal beams 3 which together with those previously mentioned and suitable bracing form a structural steel frame for supp-ortingthe components of the cooling tower. Located atintervals along the tower are vertically extending ducts 4. The upper ends of adjacent ducts are joined by a roll housingor chamber 5 provided.

Each of the ducts comprises an elongated rectangularsheet metal housing that is suspended from the upper horizontal beam Zan'd which extends downwardly. to a position adjacent to the lower horizontal beam 3. These ducts may be of any convenient length and in some cases are as much. as 45 or 50 [feet long. The lower end of the duct maybe provided with an enlarged portion '7 forming a skirt extending downwardly from the lower end thereof. The upper .end of the duct has a horizontally extending plate9 welded to it. a short distance below the top thereof; Around the outer edge of the plate '9 is a wall 11 whichforrns, withthe upper endof the duct, a trough 12 that is adapted to receive sealing material to form an air-tight connectionbetween the upper end of the duct and the upper roll'housi-ng connected therewith. It is noted that there is also formed around the inside of the trough 12 a chamber 13 through which can be circulated a cooling medium such as water.

Each of the ducts is suspended at its upper end by means of the plate 9 which rests upon a pair of channel; beams 14 'and15 that extend across the frame between the twohorizonta'l beams 2. These channels are joinedf at each end beyond the duct by means of crosspieces'lti In any. event, a cooling tower can be made to' that are bolted to the channels by bolts 17. Thus the channels and the crosspieces form a rigid frame upon which the upper end of the duct rests. The open or outer sides of the

channels

14 and 15 have welded to them plates 18 intermediate their ends and extending for a distance slightly longer than the width of a duct. The ends of the space formed between the channels and the plates are closed by small plates 19 to form chambers 21 in the channels at the portions thereof upon which the plate 9 rests. A cooling medium, such as water, is introduced to each chamber through a pipe 22 and is exhausted therefrom through a pipe 23.

The frame comprising the

channels

14 and 15 is supported on the horizontal beams 2 by means of a cradle formed of a pair of short structural steel members 24 that are bolted to the lower side of the horizontal beam 2. A plate 25 is welded to the lower surfaces of members 24, and as best shown in Figures 1 and 4, extends inwardly beyond the ends of the members 24 to form a shelf upon which the ends of the

channel members

14 and 15 can rest. Bolts 26 are used to hold the channels in place on the plates 25.

Thus it will be seen that each of the ducts 4 is individually mounted at its upper end on a rigid support. The upper end of the duct itself as well as the supports are water-cooled so that undue expansion and contraction thereof will not take place, and the supporting members will be cooled. Since the ducts are supported only at their upper ends their lower ends may expand and contract during operation of the cooling tower as the temperature of the strip passing through the individual ducts varies. In some cases the expansion of a 50 foot duct may be as high as 6 inches. Because of the construction, all of this expansion can take place in a vertical direction without causing any stress to be placed upon either the duct or its supporting members. Furthermore, the construction of the ducts permits an individual duct to be removed for repair or replacement if such is necessary. For example, most cooling towers are supplied with a reducing or a neutral atmosphere under a slight pressure in which the strip is cooled. If, for some reason, a leak should occur in one of the ducts it can easily and rapidly be replaced without the necessity of dismantling the entire cooling tower.

As the strip is moved through the cooling tower it is gradually cooled from annealing temperature to room temperature or some temperature slightly above the latter. The cooling of the strip must be controlled in accordance with some schedule in order to obtain the desired metallurgical characteristics. For this reason some of the ducts are covered with an insulating material, while others are provided with cooling coils. The ducts of the present cooling tower are admirably suited for such construction. For example, the (Fact on the left in Figure 3 is shown as being covered with an insulating material 27. This material can be placed on the duct in accordance with standard furnace practice. It is generally placed on the duct in sections since the expansion in the duct would have a tendency to break a monolithic insulating construction. The center duct shown in Figure 3 of the drawing is enlarged slightly and provided with tubes 28 on the interior thereof at each side and through which cooling water can be circulated. The tubes could, however, be placed on the outside of the duct. Generally the water will be introduced at the lower ends of the tubes and discharged at the upper ends thereof. With the construction shown herein a rigid connection can be provided between the tubes and a waste pipe at the upper ends of the ducts, but a flexible connection must be provided between the supply pipe and the lower end of the cooling pipes. The portion of the duct shown at the right in Figure 3 has neither an insulating cover nor cooling coils. This construction :is generally used toward the end of a cooling tower when the strip has reached substantially its exit temperature. 7

Above the upper end of each adjacent pair of ducts 4 is located one of the roll chambers 5 that was mentioned above. Each of these chambers has in it a roll 30 over which the strip passes. The roll is of such a diameter that as the strip passes over it the strip will be guided through the center of the ducts from which it is passing and to which it is going. Each of the rolls 30 is provided on each end with a disc or hub 31 that is mounted on a water-cooled shaft 32. These shafts, which may be a single shaft extending through the roll, if desired, are journalled for rotation in bearing assemblies 33 that will be described below. It is noted that one end only of the roll, the roll housing and its supporting structure is shown in Figure 4 since the construction is duplicated on the opposite end.

Each roll chamber is formed of a housing comprising a rectangular metal frame 34. The bottom of this chamber has two openings substantially the size of the ducts and around each of which is a downwardly extending metal skirt 35. Each skirt is received in the trough 12 at the upper end of one of the ducts as is best shown in Figures 3 and 4 of the drawing. The interior of the frame 34 is lined with an insulating refractory material 36 in order to help retain the heat that is in the strip so that the cooling rate of the strip as it passes through the cooling tower can be accurately controlled. A channel beam 37 is suitably attached as by welding, for example, to each side of the metal frame 34 and these beams are attached by bolts 38 to the upper flanges of the horizontal I-beams 2. In this manner the entire roll housing and the bearing structure for the roll is rigidly supported in the proper position on the main structural steel frame of the cooling tower above and independent of the ducts.

One end of the housing is provided with an opening through which the roll may be moved axially as the roll and the housing are being assembled or disassembled.

, construction is provided with a gasket if necessary in order to form a pressure-tight connection between the two parts. An insulating refractory 42 is used to line the inner face of the plate 39 in order to complete the insulation of the housing.

The upper end of the housing 34 has a U-shaped structural member 43 formed of sheet metal extending around its upper edge and suitably attached to the metal 34. This frame forms a trough 44 that is adapted to receive a skirt 45 extending downwardly from a removable top 40 for the roll housing. This top also is lined with a suitable insulating refractory material shown at 46. Some suitable sealing material is placed in the trough 44 in order to form a seal between the top of the housing and the sides thereof. Depending upon the material that is used for the seal and the location of the housing in the cooling chamber, it may be necessary to have the sealing material water-cooled. To this end a coil of pipe, shown at 47, encircles the housing in the trough 44 and a suitable cooling fiuid can be passed through the coil. It is also noted that the top 40 is provided with an opening adapted to receive a pyrometer 48 that may be directed toward the strip passing over the roll so that the temperature of the strip may be measured at this point. It will probably not be necessary to measure the temperature of the strip at the upper end of each of the convolutions as it is passing through the cooling tower, so roll housings which are not provided with a pyrometer may be supplied with a plug to fill the opening through which the pyrometer can extend. There is also provided a lifting ring 49 by means of which the top may be lifted from the roll housing for inspection purposes or topermit access to the same when the strip is being threaded through the tower. Normally the weight of the top 40 is sufiicient to hold it in position, but in order to prevent accidental removalof the top or to retain the top in place in case the pressure in the system increases for some reason there is provided a latch which will permit sufficient movement of the top to permit a pressure release through the seal. To this end there is provided an angular latch 51 that is pivoted to a member '2 projecting upwardly from the top. it will be seen that there is enough space between the lower horizontal portion of the latch and the top of the frame 34- 'so that the top can move upwardly a distance approximately equal to the level of the sealing material in the trough The top of the roll housing, however, cannot be completely removed uniess the latches are thrown back against it.

The roll shaft 32 extends through a central opening formed in the plate 39 and is received by a bearing 53 forming part of the bearing assembly 33 that was mentioned above. The inner race of this hearing is snugly received on the surface of the shaft 32 while the outer race is received by a housing 54. This housing will preferably take the form of a casting that is provided with a water-cooled chamber 55 on the side toward the roll chamber. The housing 54 is also provided with a lifting ring 56 by means of which the entire roll chamber may be moved when the bolts hfi have been removed.

As was indicated above, it is generally necessary to provide either a neutral or a reducing atmosphere in the entire cooling chamber. in order to prevent or remove oxidation from the surface of the strip while it is being cooled from its annealing temperature to the exit temperature. Since it is necessary to maintain the atmosphere in the cooling tower under a slight pressure a sealing means is used around the roll shaft to prevent leakage of this atmosphere and to prevent oxygen from entering the cooling tower. To this end there is provided a bellows member 57 which extendsbetween the plate 39 and the casting 54-. This bellows member is provided with outwardly extending flanges on both ends thereof that are suitably attached in a pressure-tight fashion to the casting, 54 and to the plate 39. On the left end of the shaft beyond the bearing, as seenin Figure 4 there is provided a grease seal 58 of conventional construction. This seal surrounds the shaft and prevents the flow of gas along the same. A rod 59 extending between the grease seal and the casting 54 prevents rotation of the seal when the shaft is being rotated. There is also provided a bellows 64 surrounding the shaft and extending between the bearing housing 54 and the grease seal. This bellows, like the bellows 57, is provided on its ends with outwardly extending flanges that are fastened in pressure-tight relation to the housing 54 and the grease seal 58 respectively.

The bearing housing 54 is supported upon a beam 62 that extends between the two channel members 37 in a position to hold the shaft concentric with the central opening provided'in the plate 39. The housing is bolted to the upper flange of the beam while the lower flange thereof is bolted to a horizontally projecting portion of an angle member 63 that is suitably welded to the side of the channel 37. Thus the weight of the roll, its shaft and bearing assemblies are supported by the frame of the cooling tower rather than by the roll housings.

Shaft 32 is water-cooled and for this reason is made in the form of a tube as shown in the drawing. Water is introduced into the inner end of the shaft by means of aninlet pipe 66. This pipe is held in position concentric with the shaft 32 by means of a flange 67 that is welded thereto with the flange being bolted to a casting 68. This casting is mounted on

cross-members

69 and 71 which also extend between the channel members 37 and which are bolted to the angle iron 63 in the same fashion as was the beam 62. Water is introduced into the shaft 32 through pipe66 and it flows back through the shaft 32 to the housing 68 where the overfiow is collected and passes out through a drain 72. The level of the water in, the

as the upper ones in construction.

shaft 32 is maintained byrmeans' of a disc or washer-"73 that is bolted to the end of the shaft.

From the above description it will be seen that the roll housing and the roll supporting assembly are attached to suitable structural members that are in turn removably fastened to the framework of thecooling tower. There are provided seals between the roll chamber proper and the top of the ducts which connect therewith as well as between the sides and the top of the rollc-harnber. There are also provided seals between the roll chamber and the bearing for the shaft so that a desired. atmospherernay be maintained within the entire cooling chamber. When it becomes necessary to open theroll chamber, as for threading the strip through the tower, it is onlynecessary to remove the top of the housing. When-it is necessary for some reason to substitute one roll for another or to repair the rolls, the bolts 38 on each end of the supporting members 37 can beiloosened and-theentire roll and housing assembly removed. At this time another housing assembly can be lowered into place so that the one which was removed can be repaired without the necessity of closing down the entire cooling tower for any lengthy period of time.

The bottom roll housings 6 are, in general, the same The roll supporting bearings and shaft water-cooling provisions are the same as those in the upper roll chambers and need not be described in detail again. ltis noted, however, that the bearing. assemblies 33 and the castings 68 of the lower rolls are inverted with respect to the bearing assemblies 33 and castings 68 of the upper roll chambers.

As shown in the drawings, .each of the lower roll chambers is formed by a. rectangular metal frame 75 that is lined with an insulating'iefractory 76. Attached to each side of the frame is a channel member 77 the ends of which extend beyond the ends of the housing and are bolted to the lower flanges of the horizontal supporting beams 3., as best shown in Figure l of the drawing. Each of the housings is provided in its upper portion with a pair of openings that are aligned with the lower ends of adjacent ducts 4. Around each of the openings there is sheet metal work 7% forming a trough 81 that receives the skirt 7 on the lower end of one of the ducts, and a chamber 82 through which the cooling liquid may be circulated. Each of the frames is-also provided with a downwardly extending skirt S3 at its lower end which is received in a trough 34 formed around the outer edge of the bottom he" of the roll chamber. As shown, this bottom is also lined with an insulating refractory material 86. The bottoms are held in position against the lower end of the frame 75 by means oftabsiifl which project upwardly from each corner of the metal forming the trough 34. These tabs are provided with openings that receive projections 83 extending from the corners of the frame 75. The manner of removing the bottom from the chamber can best be described with respect to Figure 5 of the drawing. Referring to that figure it will be seen that the bottom can be moved to the right or to the left sufficiently for the tabs 87 on one end thereof to move off the projections 88. The bottom can then be tilted downwardly and moved in the opposite direction until the tabs 87 on the other end thereof have been removed from the opposite projections S8. It is noted that instead of having individual projections it on each corner of the housing these parts can be made of a pair of rods each extending from one end to the other of the housing along the side thereof. If

this is the case, the bottom can be supported while the Extending between the channels 77 near the ends thereof are crosspieces 91 that are attached to angle members 92 which are welded to the channel in the same manner as angle members 63 were attached to the upper channel members 37. The bearing assemblies and the cooling water housings for the roll shaft are suitably bolted to these cross members 91, as is shown at 93 in Figure 2 of the drawing.

It will be noted that the troughs 81 on the upper part of the lower housings 6 are considerably deeper than the troughs 12 formed on the upper ends of the ducts. The reason for this is that the ducts are supported at their upper ends so that the lower ends are free to expand and contract as much as is necessary. The troughs 84 must be deep enough so that the head of the sealing fluid in the trough will withstand the pressure that is normally maintained within the cooling tower. In the description, so far no mention has been made of the type of material used for forming the various seals between the ducts and the housings and between the ends of the housings and the body thereof. In view of the fact that the upper ends of the ducts are relatively stationary with respect to the openings provided in the lower portion of the upper housings, any suitable granular or liquid sealing medium may be used. The same is true of the seals etween the upper housing and the top thereof and between the lower housing and the bottom of the same. The sealing medium used between the skirt 7 on the lower end of the ducts and the troughs 84 on the upper portion of the lower housing, however, must be of some material that will withstand the heat of the strip as well as a material that has su'fiicient viscosity to resist the pressure that is maintained in the cooling chamber. It has been found that roofing tar will satisfy the requirements of such a seal. While this tar has a relatively high flash point it is nevertheless protected from the heat of the strip by the cooling chamber 82 that extends around the inside of the opening through which the strip passes. Roofing tar may also be used for the other seals, since a cooling chamber or cooling coils are provided for each trough that receives a sealing material.

From the above description it will be seen that the cooling tower of this invention comprises a number of individual ducts, each of which is mounted at one point only so that it may expand and contract with respect to the rest of the apparatus. These ducts can also be removed and replaced individually without tearing down the entire cooling tower if such becomes necessary or desirable. This is of particular advantage where it becomes necessary to change the number of insulated or water-cooled ducts that are used for a particular cooling cycle. The construction of the cooling tower also permits each of the upper and lower roll housings to be removed individually and replaced with substitutes when it becomes necessary to repair or change one of the rolls. This construction permits quick and easy interchange of parts with a consequent shortening of any down time. The construction disclosed herein also is admirably suited for maintaining a complete pressure-tight system with a minimum of permanent joints between the various portions of the cooling tower. This means that the various joints are automatically sealed as the parts are moved into position upon assembly of the cooling tower.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me it will be apparent to those skilled in the are that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention, as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

. 1. In a cooling tower through which strip metal is moved in a series of loops, the combination of a plurality of vertically extending parallel ducts through which the strip moves, means to support each duct solely adjacent to its upper end whereby the lower end of each duct hangs free and is free to expand and contract, structure forming a roll chamber having a pair of openings in the bottom thereof of a size substantially equal to the size of said ducts and spaced apart a distance substantially equal to the spacing of adjacent ducts, means to mount said structure independently of said ducts and out of engagement therewith and with the openings therein above the upper ends of a pair of adjacent ducts, sealing means between each duct and the opening adjacent to the upper end thereof to form a closed passage between the chamber and the ducts, a roll in said chamber, and means for mounting said roll for rotation whereby strip passing from one duct can be guided through said chamber by said roll and into the adjacent duct.

2. In a cooling tower, a frame, a pair of elongated ducts, means to suspend each of said ducts in vertical side by side relation from its upper end on said frame, means forming a trough around the top of each duct, a rectangular housing having a bottom provided with two openings, each substantially the size of one of said ducts, a skirt extending downwardly around each opening, means to mount said housing independently of said duct on said frame with the skirts received respectively in the troughs, sealing means in said troughs around said skirts, a removable top for said housing, means forming a seal between said top and housing, and a roll in said housing over which a strip of material can pass as it moves from one duct to the other.

3. The combination of claim 2 including a shaft for said roll extending through said housing, bearings for said shaft, means to mount said bearings on said frame, and seal means between said shaft and said housing.

4. In a cooling tower, a supporting frame, a pair of elongated ducts, means to suspend each of said ducts vertically on said frame in side by side relation, said mounting means engaging said ducts only at the upper end thereof whereby the lower end may be free to move vertically as a result of expansion and contraction of the duct, a rectangular housing having a top in which there are a pair of openings substantially the size of said ducts, means forming a trough extending upwardly around each of said openings, means to mount said housing on said frame beneath said ducts with the lower ends of said ducts extending into said troughs, sealing means in each trough, and a roll in said housing over which a strip can pass as it travels from one duct to the other.

5. The combination of claim 4 including a shaft for said roll extending through said housing, bearings for said shaft, means to mount said bearings on said frame, and seal means between said shaft and housing.

References Cited in the file of this patent UNITED STATES PATENTS 496,208 Procunier Apr. 25, 1893 1,698,347 Puening Ian. 5, 1929 1,765,955 Von Maltitz June 24, 1930 1,968,442 Clark et al. July 31, 1934 2,035,312 Greer et al. Mar. 24, 1936 2,156,352 Peterson May 2, 1939 2,168,028 I-larsch Aug. 1, 1939 2,206,734 Stassinet July 2, 1940 2,261,702 Tamele et al Nov. 4, 1941 2,278,136 Otis et a1 Mar. 31, 1942 2,345,181 Cooper et al Mar. 28, 1944 2,418,087 Nachtman Mar. 25, 1947 2,513,713 Cope July 4, 1950 FOREIGN PATENTS 263,162 Great Britain Sept. 15, 1927 357,575 Great Britain Sept. 21, 1931 557,029 Great Britain Nov. 2, 1943