US1978894A - Rolling mill - Google Patents

Description

W. R. CLARK @QL 3G, E934.

ROLLING MILL 3 Sheet-Sheet l Filed June 20, 1930 ROLLING MILL Filed Jun 20, 1950 3 SheetS-Shefl 2 gwmnfoz 30, 1934. W R CLARK I n 1,978,894

ROLLING MILL Filed June 2o, 1930 s sheets-sheet 3' aucun iatented Oct. 30, 1934 ROLLING MILL Walter R. Clark, Bridgeport, Conn.

Application June 20, 1930, Serial No. 462,502

27 Claims.

This invention relates to a rolling mill and more especially to a rolling mill in which the size of the pass or opening between the rolls of the mill is controlled and maintained within predetermined in order to maintain an even 4or uniform gauge in the material delivered by the rolls from end to end and edge to edge of a given piece, or from end to end of a plurality of pieces fed successively through the rolls of the mill.

In the past, the control of gauge variations has been more or less ineffective, the production of sheets or strips within the gauge variation permissible in commercial production depending' l5 largely on the skill of the mill operator.

It is relatively an easy matter in mill design to shape the rolls so as to take care of the bending thereof under the great pressures the rolls are subjected to during the rolling operation. However, the general and local expansions of the mill rolls, due to the heat generated by the rolling of strips or sheets of various widths and degreesof hardness, producesan eifect which must be largely controlled by a skilled operator through the use of lubricant and cooling and heating fluids. A

In my prior application, Serial No. 251,430, led February 2, 1.928, I have disclosed a method and apparatus for rolling metal wherein the temperatures of the rolls of a rolling mill are controlled and maintained within predetermined limits by the application of hot or cold uids applied to the surfaces of the rolls, the application of the heat transferring mediums being automatically "subjected to the roll temperatures.

The invention of the present application relates to further renements in the controlling of the roll temperatures, whereby the expansion and contraction of the rolls, due to changes in temperatures, may be closely controlled in order that the material delivered by the mill or mills may be of uniform gauge.

As a general object of my invention, I contemplate an arrangement for maintaining a substantially constant predetermined temperature in the rolls of a mill or tandem of mills.

A further object of the invention is to maintain a substantially constant temperature throughout the length of a mill roll regardless of the width of the strip or sheet being rolled.

A feature of the invention resides in an improved arrangement whereby'localized heating effects, due to the rolling of narrow strips or to hother facts incident to metal rolling, may be controlled bya heat responsive device or devices terior structure;

Fig. 3 isa view of the right-hand mill shown in Fig. 1, together with the roll temperature con trolling means therefor;

Fig. 4 is a plan view of the mill shown in Fig. 3, 70 but partly broken away, and

Figs. 5, 6 and 'l are diagrams of the control circuits used in connection with the three millsv shown in Fig. 1.

Referring now to the drawings in which I have illustrated my invention by showing a preferred embodiment of the same, the reference numeral 10 indicates in general a mill tandem comprising mills 11, 12 and 13, of which mill 11 is a two-high mill while mills 12 and 13 are four-high mills, the 80 types of these mills not forming any part of the invention since the latter may be carried out with any usual form of mill. The material 14 enters mill 1l with a greater thickness and a relatively lower temperature than it emerges from this mill. The increase in temperature results. among other causes, from the friction between the mill rolls and the material, and the internal friction of the material during the breaking-down process incident to the reduction in the gauge of the material. Due to the generation of heat between the mill rolls, the temperature of the latter tends to rise with the result that the rolls expand in diameter and cause a decreased thickness in the material delivered. The operator, in order to counteract this effect, ordinarily subjects the rolls to cooling fluids and the material and sometimes the roll necks to lubricants, according to his judgment and experience.

I propose to maintain the rolls at a constant temperature regardless of the heat generated by the act of rolling, 'and independently of any cooling uid or lubricant to which the roll or material is subjected by the operator. This I do by enclosing the rolls in chambers in which the temperature is maintained at a predetermined amount, which should be higher than that ofthe material entering between the rolls'of the mill and preferably somewhat lower than the temperallre Qi the material leaving the roll. Thus, a

relatively cool material entering the rolls absorbs heat therefrom, which is more or less restored to the rolls during the act of rolling.

In the form shown in connection with mill 1l of Fig. 1, a chamber surrounds the roll 16, except on the side towards the mill roll 17, the latter being surrounded by a chamber 18 open on the side towards the roll 16. A gap 19 is formed sive device exposed to the temperature within the chamber 15 and generally designated by the referencenumeral 24 and having suitable connections with a ow controlling-valve 25.

In Fig. 5 of the drawings I have shown somewhat diagrammatically a preferred arrangement for controlling the ow of heating uids to pipes 21, 22 and 23 by means of valve 25, in which the I reference numeral 26 indicates a thermocouple carried within the chamber 15 and subjected to the temperature therein, the thermocouple 26 being connected in series with a coil 27`of solenoid switch 28, the switch arm 29 of the latter being held in contact with switch points 30 and 31 by means of tension spring 32 when the interior of the chamber 15 is below normal operating temperature. In this position of the switch 28, the

circuit containing the solenoid switch 33 is closed, causing the latter to close the circuit containing solenoid coil 34, which by action on armature 35,

having suitable connections vwith valve 25 opens the latter to permit hot water or steam, or other heating uid, to pass into the pipes 21, 22 and 23. In the form shown, the valve 25 is provided with an arm 25 connected to a lever 35a by means of link 25h, the lever 35 being connected to and operated by armature 35.

When the interior of the chamber 15 reaches normal working conditions, the eiect of the heat therein on thermocouple 26 is such as to cause suliicient ow of current through coil 27 to overcome the'tension of spring 32, whereupon the solenoid switch arm 29 moves from contact with points 30 and 31 into contact with points 36 and 37, opening the circuit of solenoid switch 33 and closing that of solenoid-switch 38. The energizing of solenoid switch 38 closes the circuit in which coil 39 is connected, moving the armature 35 into position to close the valve 25, thus cutting 01T the iiow of hot water or other fluid from pipes 21, 22 and 23,

At each end of chamber 18 is an arcuate pipe 40, pipes 40 being connected together by longitudinally extending pipes 41. 'I'he ow of hot water or steam to these pipes is controlled by a valve '42 which is opened or closed by armature 35 simultaneously with valve 25.

From the above description it will be readily understood that the rolls 16 and 17 are maintained at a substantially constant temperature independently of the presence of any material passing between the rolls, so that there is no tendency on the part of the rolls to cool due to interruptions in the rolling process, such as occur when successive strips are fed through the rolls of the mill.

Mill I2 is provided with chambers 43 and 44.

Lavaca@ through solenoid switches 51 and 52. In Fig. 6

I have shown diagrammatically a suitable control circuit for the electric heaters of mill 12. As shown, the temperature within th e chambers has reached normally operating conditions so that the current generated by thermo-couple owing through coil 53 and acting on armature 54, has withdrawn switch arm 55 from contact with points 56 and 57 into contact with points 58 and 59, closing the circuit containing solenoid coil 60 and moving the armature 61 and switch arm 62 out of contact with points 63 and 64', thus opening the circuit in which the heating coils 49 are placed. If the temperature within the chambers decreases below that of normal operating temperature insuiicient current will be generated by the thermo-couple 50 to overcome the tension in spring 65, whereupon the latter will move the switch arm 55 into contact with switch points 5,6 and 57, thus closing the circuit of coil 66, which acting on armature 61, will bring arm 62 into contact with switch points 63 and 64, closing the circuit of the heating coils 49.

In certain instances, in order to produce more localized expansions or contractions ofthe mill rolls, I provide one or more heat transferring units which preferably are adjustable into contact with any portion of the roll surface. As a suitable means to this end, a bar 67, (Figs. 3 and 4) may be disposed adjacent to and extending longitudinally of a roll 68, bar 67 serving to support one or more heat transferring units 69 which, in this instance, are mounted on bar 67 by means of bolts 70 passing through the units and through the longitudinal slot 71 in bar 67. By loosening bolts 70 the units 69 may be adjusted to any position lengthwise of the roll.

Each unit 69 comprises a hollow 'box-like frame 72, the open side 73 of which is applied' to the surface of roll 68. Within each box 72 is a heating coil 74, the ow of current to which is controlledl by a thermostat, thermo-couple or other heat responsive device generally designated by' the reference numeral 75. In 7 of the drawings, I have shown diagrammatically a suitable control circuit for the heating coils 74 in which the reference numeral 76 indicates a thermocouple which is in line with coil 74 and subjected to the temperature of roll 68 and connected to an indicating pyrometer or similar device 77, having a movable arm 78 connected to armature 79, actuated by coil 80 in series with thermo-couple 76. 'Ihe reference numeral 81 indicates a switch point with which arm 78 contacts to close the circuit of solenoid switch coil 82, the latter moving the armature 83 and switch arm 84 out of contact with switch points 85 and 86 to open the circuit of solenoid coil 87 of switch 88, the latter opening the circuit of the heating coil or coils 74. 'Ihe switch point 81 will ordinarily be adjusted to require a predetermined temperature of the roll surface before suihcient current is generatedv bythe thermo-couple 76 to bring arm 78 into contact with point 81.

As the temperature of roll 68 decreases the thermo-couple cools and the amount of current generated thereby falls until arm- 78 disengages from contact with switch point 81, thereby opening the circuit of solenoid coil 82 and permitting tension spring 89 lto move switch arm 84 It will be readily understood that by reason of the fact that the rolls of my improved mill are operated at a constant temperature, the tendency of the gauge of the material being rolled to vary, due to variations in the roll temperature, is substantially, if not entirely, eliminated so that I am able to obtain substantially uniform gauges in the material without the care and skill required in the usual mill.

While I have shown and described a `preferred embodiment of my invention, it will be understood that' it is not to be limited to all the details shown but is capable of modification and variation within the spirit of the invention and the scope of the appended claims. i

I do not claim broadly herein the combination with a rolling mill for rolling metal and having solid rolls therein of means for applying a heating medium to the outer working surfaces of the rolls and means controlled by the temperature of the outer working surfaces of the rolls 'for operating the means for applying the heating medium, as claimed in my application Serial N0. 251,430, led February-2, 1928.

What I claim is:

1. In a rolling mill having a roll, the combination of means for automatically controlling ithe temperature of a restricted .portion of the roll, and means for independently controlling the temperature of the remainder of the roll.

2. In a rolling mill having a roll, the combination of means for maintaining the roll at a predetermined temperature, means for modifying the temperature of a portion of the roll, and means subject to the temperature of said roll portion for varying the action of said temperature-modifying means.

3. Ina sheet rolling mill having a roll, the combination of means for supplying heat generally to the roll to maintain it at a proper rolling temperature, means for setting said means in operation when the temperature of the roll falls below a certain limit, and independently operable means for applying heat to limited portions of the roll surface for controlling the conl tour of the sheet-engaging portion of the roll.

4. In a rolling mill having a roll, the combination of means for supplying' heat generally to the roll to maintain it at a proper rolling temperaturer-means to-vary the temperature ofthe roll automatically so as to prevent its passing a certain limit in at least one direction, and a heat transfer unit associated with a limited portion of the roll surface.

5. In a rolling mill'having a roll, the combination of means for supplying heat generally to the roll to maintain it at a proper rolling temperature, a heat transfer unit associated with a* limited portionl of the roll surface, and means subjected to the temperature of the roll for controlling the` transfer of heat throughsaid unit.

6.'In a rolling mill having a roll, the combination of means for supplying heat generally to the roll to maintain it at a proper rolling temperature, aA heat transfer unit associated with a limited portion of the roll surface, and means subjected to the roll temperature at the surface thereof for controlling `the transfer of heat through said unit.

'11. in a ronmg mm having a'rou, the combination of means forming a chamber in which the roll is mounted, means for supplying heat within said chamber to heat said roll, and independent means for producing the transfer of heat with respect to a limited portion of the roll.

8. In a. rolling mill having a roll, the combina- -tion of means forming a chamber in which the roll is mounted, means for heating the interior of said chamber to thereby heat said roll, and independent means associated with a limited portion of the roll for producing local heat exchange.

9. In a rolling mill having a roll, the combination of means forming a chamber in which the roll is mounted, means for heating the interior of said chamber to thereby heat said roll, means for controlling the introduction of heat within said chamber to limit the heating of the roll to normal rolling temperature, and independent means associated with a limited portion of the roll for producing local heat exchange.

10. In a rolling mill having a roll, the combination of means for maintaining the roll at a proper rolling temperature including self-acting means for lchanging the temperature when a certain limit is passed, and independent means for varying the roll contours, said last named means comprising means for heating limited portions of the roll surface.

11. In a rolling mill having a roll, the combination of means for supplying heat generally to the roll to maintain it at a proper rolling temperature, means for changing the temperature of the roll automatically when a certain limit is passed, and independent means for varying the roll contours, said independent means being adjustable to affect different portions of the roll surface.

12. In a rolling mill having a roll, the combination of means forming a chamber in which the roll is mounted, means for heating the interior of said chamber to thereby heat said roll, means for controlling the introduction of heat within said chamber to limit the heating of the roll to normal rolling temperature, independent means associated with a limited portion of the roll for producing local heat transfer, and means subjected directly to the roll temperature for controlling the transfer of heat through said inde'- pendent means.

13. In a rolling mill having a roll, a support, and a plurality of heat transfer units for controlling the temperature of said roll, said units being mounted for independent adjustment with respect to the roll surface, and a plurality of devices subjected to the temperature offthe rollat the sur- 130 face thereof for controlling the flow ofv heat plurality of heat transfer units associated with said roll for controlling the temperature of different portions of the roll surface, said units being mounted on said support for independent adjustment lengthwise of the roll, and a plurality of control devices corresponding in number to said units subjected to the temperature of the roll at the surface thereof for controlling the flow of heat automatically through said units individually.

15. A mill for cold rolling sheet material having in association with one of its rolls a plurality of thermo-responsive devices adjacent the roll surface at different points in the length of the metal contacting portion of said roll and heat transfer apparatus comprising devices at corresponding points in the length of said roll condinvasor.

trolled respectively by'said first-named devices for heating the roll automatically.

16. A mill for cold rolling sheet material having in association with one of its rolls a plurality of thermo-responsive devices adjacent the roll surface at diere'nt points in the length of the metal contacting portionof said roll and heat transfer devices for varying the roll surface temperature located at corresponding points in the length of said roll and controlled respectively by said first-named devices.

17. A mill for rolling sheet material having in association with one of its rolls a plurality of thermoresponsive devices at different points in the length of said roll, heat transfer devices for varying the roll surface temperature located at different points in the length of said roll and controlled respectively by said rst-named devices, and means whereby said heat transfer devices may be individually adjusted relatively to the roll surface.

18. A mill for rolling sheet material and having in association with one of its rolls a plurality of thermoresponsive devices at different points in the length of said roll, heat transfer devices for varying the roll surface temperature by supplying heat to the roll surface located at different points in the length of said roll and controlled respectively by said rst-named devices, and means providing for the independent adjustment of said heat transfer devices in a direction lengthwise of the roll. y

19. In a rolling mill having a roll provided with a at face for rolling sheets, the combination of means for heating the roll, means for setting said heating means in operation when the temperature of the roll -falls below a predetermined limit, means for varying the temperature of a restricted portion of the roll tobring about a predetermined contour of such portion during rolling, and means subject to the temperature of said roll portion for automatically controlling the operation of said last-named temperature-varying means.

20. In a rolling mill, a roll, means for controlling the temperature of said roll, said means including a support and heat transferring elements mounted on the support for independent relative adjustment lengthwise of the support and of the roll, said heat transferring elements being adapted to impart heat to the roll surface, and means subjected to the temperature of the roll at the surface thereof for controlling the -transfer of heat to the roll through said elements so that such transfer is effected automatically.

21. In a rolling mill having a roll provided with a fiat face for rolling sheets, the combination of means for maintaining within certain limits the temperature of the roll as a whole during rolling, said means including a heat transfer device and means for setting said device in operation automatically when the temperature passes a certain limit, and means for varying the temperatm'e of a restricted portion of the roll to bring about a predetermined contour of such portion during rolling.

22. In a rolling mill having a roll provided with f a flat face for rolling sheets, 'the combination of means for maintaining within certain limits the temperature of the roll as a whole during rolling, said means including a de'vice for transferring heat to the roll surface and means for setting said device in operation when the temperature passes a certain limit, and means for varying the temperature of a restricted portion of the roll to bring about a predetermined contour of such portion during rolling.

23. A mill for cold rolling sheet material having in association with one of its rolls a plurality of thermoresponsive devices adjacent the roll surface 'at dierent points in the length of said roll adapted to be actuated by variations of the roll surface" temperature, and heat transfer devices for imparting additional heatV to the roll surface located at different points in the length of said roll and automatically controlled respectively'by said first-named devices.

24. A mill for rolling sheet material having in association with one of its rolls a plurality of thermoresponsive devices adjacent the roll surface at different points in the length of the metal contacting portion of said roll and heat transfer apparatus comprising devices at corresponding portions of the length of said roll controlled respectively by said first-named devices for heating the roll automatically.

25. A mill for rolling sheet material having in association with one of its rolls a plurality of thermoresponsive devices adjacent the roll surface at different points in the length of the metal contacting portion of said roll and heat transfer devices for varying the roll surface temperature located at corresponding points in the length of said roll and controlled respectively by said rstnamed devices.

26. In combination with arolling mill for rolling metal and having solid rolls therein, means forming a chamber enclosing said rolls, means for applying a heating medium to the outer working surfaces of the rolls, and means controlled by the temperature of the outer working surfaces of the rolls for operating the means for applying the heating medium.

27. In combination with a rolling mill for rolling metal and having solid rolls therein, means forming a chamber enclosing one of said rolls,

, means for supplying heat to the outer working surface of said roll, and means controlled by the temperature of the outer working surface of said roll for setting said heating means in' operation when the temperature falls below a predetermined limit.

\ WALT@ R. CLARK.

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