US3069942A - Rolling mills - Google Patents

Description

P. s. E. FREDRIKSSON 3,069,942

ROLLING MILLS Dec. 25, 1962 Filed June 20, 1955 3,@69,942 RQLLZENG MKLLd Per Sven Eneelbrelst Fredrihsson, Vasteras,

Unite Sweden, assignor to Ahtieholaget dvensha Metailverhen, Vasteras,

For the discharge of smoke, oxide dust etc., resulting from rolling operations, suction caps or hoods are usually provided above the sets of rolls, which caps communicate with a fan for drawing off the impure air. Additionally, suction nozzles for the partial exhausting of impurities are usually located at particularly exposed places in the set of rolls. Said suction caps are bulky and tend to prevent ready access to the rolls for control and adjustment. Furthermore the pipe lines or ducts required encroach upon the necessary freeness in working in the rolling mill. Additionally, due to the difficulties in excluding the surrounding air from the space inside the caps, said suction means will not be satisfactorily efiicient in operation and smoke escaping into the space outside the sets of rolls will cause hygienic disadvantages which sometimes will prove of dangerous nature.

By applying the present invention said inconveniences are avoided thereby that, for carrying away the smoke, oxide dust etc. caused in the rolling operation, the pit commonly located below each set of rolls for the collection of cooling liquid from the set of rolls, is utilized.

Accordingly the invention is characterized in a pit for the collection of cooling liquid from the set of rolls ar ranged below each pair of rolls, which pit communicates With evacuating means adapted to maintain sub-atmospheric or negative pressure in the pit for the exhaust of the smoke, oxide dust etc. from the set of rolls.

The invention will now be more fully explained with reference to an embodiment diagrammatically shown in the attached drawing, and in connection therewith further characterizing features of the invention will be set forth.

FIGURE 1 is a sectional view through a set of rolls with the pit arranged below same and also a drain line and settling basin connected thereto.

FIGURE 2 is a detail of a modified embodiment of the arrangement as shown in FIGURE 1.

FIGURE 3 is a frontal veiw of a set of rolls provided with an arrangement according to the invention for encasing the set of rolls.

FIGURE 1 illustrates a set of rolls generally designated by reference numeral 1. The set of rolls is encased or housed to substantially exclude the surrounding air and arranged below the set of rolls, in a way known per se, is apit 2 for the collection of cooling liquid from the set of rolls. The pit 2 is connected by means of a duct 3 to a settling basin i. Arranged in the settling basin is a weir 5 and placed in the portion 6, of the basin, located beyond the weir in the direction of flow of the liquid is a line 7 for returning the cooling liquid to the set of rolls by means of the pump 8. Connected to the basin 4 and preferably to the remote portion 6 of same is a tube or duct 9 for the exhaust of impure air by means of the fan it}. Connected to the basin by means of separate ducts 3 are preferably the pits of a plurality of sets of rolls. The fan it) will induce a sub-atmospheric or negative pressure in the system including the sets of rolls, pits 2, ducts 3 and basin 4. The basin is preferably dimensioned in such a way that the space l1 located above the liquid in the basin has such a large vertical section that the velocity of the impure air passing through the basin Will be so low that the major portion of the moisture and oxide dust entrained in the air will have time to settle.

3,959,942 Patented Dec. 25, 1952 In other words, even though a negative pressure is maintained in the basin 4, the volume of the basin 4 is so large with respect to the cross sectional area of the duct 3 that the velocity of air flowing from the duct 3 into the basin will be suddenly reduced to such an extent that the air in the basin 4 is almost static. Consequently the air will remain in the basin 4 for a relatively long period of time which will permit the majority of the heavier than air impurities therein to settle out with the relatively pure air being exhausted from the basin 4 by the fan 1%.

In the modified embodiment shown in FIGURE 2 it is not the intention to return the cooling liquid. The liquid coming from the pit, not shown, will be passed through the duct 12 into a water trap 13 and from thence through the duct 14 outwardly to a suitable drain. Connected to that part of the system, including the duct 12, is a tube 15 so that the part in question can be placed under subatmospheric or negative pressure by means of the fan to.

In order that the described arrangement involving gas exhaust shall be as efficient as possible in operation it is preferred,r.". mentioned, to substantially exclude the set of rolls from the surrounding air. This may be accomplished e.g. through the arrangement of plates forming a housing around the set of rolls as will be evident from the diagrammatic views of FIGURE 1 and FIGURE 3. However, the plates in question should be provided with openings for the introduction and discharge of the hot work to be rolled. FIGURE 13 shows a prefer-red manner of arranging the openings when the set of rollers is provided with a plurality of rolling grooves. In this case the opening is arranged to accomodate one rolling groove at a time, the opening then being arranged in the feed and discharge boxes respectively, placed in front of the rolling groove in question. When changing from one rolling groove to the other the boxes have to be displaced and consequently also the openings. In FIGURE 3 reference numeral 17 designates the feed box which is arranged upon a plate element 18, suitably of the same Width as the box. Arranged on either side of the plate element 18 are plate elements 19-46, which elements are provided with no openings. At least two of said elements should have the same width as the centre to centre distance between the rolling grooves. In the drawing the plate elements 20-25 are shown as of said width while the plate elements 19 and 26' are Wider. All of the said plate elements Kid-4.25 are easily detachable and suitably pivotally supported from an axis of rotation 27 in order to facilitate opening thereof to provide access to the rolls. The plates 13-26 provide a sectional housing surrounding the rolls to substantially exclude outside air and to permit the air surrounding the rolls to be withdrawn by the exhaust system. As above stated, the plates 182t5 may be arranged in any desired combination according to widths which will result in proper feeding and discharge of work.

The displacement of the feed and discharge openings may be performed in the following way. If e.g. from the position shown in the drawing the feed box 17 is to be displaced to the rolling groove located next to the left, cg. the element 22 and element 18 are removed and the feed box 17 displaced to abut against the element 21, whereupon the element 22 will be inserted between the element 13 and the element 23.

in addition to the above advantages of the invention free it should be emphasized that thanks to the possibility of utilizing the settling basin for the precipitation of moisture, further cleaning of the air exhausted from the basin 4 will be greatly facilitated since the same is substantially dry and is far more easily cleaned than moist air.

The invention is not limited to the embodiment shown 3 but different modifications are possible within the scope of the claims.

Having now describedthe invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a rolling mill having at least one pair of rolls, a housing surrounding said rolls, said housing comprising a plurality of removable pivotally mounted plates of difierent widths, a pit disposed below said rolls and communicating with said housing, a closed settling basin, a duct connecting said pit and said basin and an exhaust fan connected to said basin at a point remote from said duct whereby to provide a sub-atmospheric pressure in said basin to draw air from said housing through said duct into said basin, the cross-sectional flow area of said basin being so large with respect to the cross-sectional flow area of said duct that the velocity of air flowing from said duct into said basin is reduced to an extent such that the flow of air in said basin has a velocity so low that solid impurities entrained in said air will settle out in said basin.

2. In a rolling mill having at least one pair of rolls, a housing surrounding said rolls, a pit disposed below said rolls and communicating with said housing, a closed settling basin, a duct connecting said pit and said basin and an exhaust fan connected to said basin to provide a sub-atmospheric pressure in said basin to draw air from said housing through said duct into said basin, the crosssectional flow area of said basin being so large with respect to the cross-sectional flow area of said duct that the velocity of air flowing from said duct into said basin is reduced to an extent such that the flow of air in said basin has a velocity so low that impurities heavier than air entrained in said air will settle out in said basin.

3. In a rolling mill having at least one pair of rolls, a housing surrounding said rolls, a closed settling basin,

a duct connecting said housing and said basin and an exhaust fan connected to said basin to provide a subatmospheric pressure in said basin to draw air from said housing through said duct into said basin, the cross-sectional flow area of said basin being so large with respect to the cross-sectional flow area of said duct that the velocity of air flowing from said duct into said basin is reduced to a velocity such that impurities heavier than air entrained in said air will settle out in said basin.

4. In a rolling mill having at least one pair of rolls, a housing surrounding said rolls, a pit disposed below said rolls and communicating with said housing, a closed settling basin, a duct connecting said pit and said basin and an exhaust fan connected to said basin at a point remote from said duct whereby to provide a sub-atmospheric pressure in said basin to draw air from said housing through said duct into said basin, the cross-sectional flow area of said basin being so large with respect to the cross-sectional fiow area of said duct that the velocity of air flowing from said duct into said basin is reduced to an extent such that the flow of air in said basin has a velocity so low that solid impurities entrained in said air will settle out in said basin.

References Cited in the file of this patent UNITED STATES PATENTS 265,731 Altmeyer Oct. 10, 1882 1,629,451 Braren May 17, 1927 2,158,315 Wheeler May 16, 1939 2,316,571 Dunmire Apr. 13, 1943 2,358,868 Marx Sept. 26, 1944 2,360,504 Masse Oct. 17, 1944 2,578,040 Booth et al. Dec. 11, 1951 2,756,617 Kaplan et al. July 31, 1956

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