Method of and Apparatus for Cleaning Cylinders or Rolls

Abstract

With a method of cleaning cylinders (5) and/or rolls (5), e.g., working rolls (5) in a rolling stand, which are used for producing a rolled stock (1) such as strips or slabs, wherein a liquid is sprayed onto the cylinders (5) at high pressure through several nozzles D1-Dn, a number of nozzles (D1-Dn) are stationary arranged in and/or on a nozzle beam (10), at least one on-off valve is associated with each nozzle (D1-Dn), and one or several nozzle(s) (D1-Dn) are sequentially switched on and off one after another starting from one end of the nozzle beam. The invention further relates to a corresponding apparatus.

Description

The invention relates to a method of and an apparatus for cleaning cylinders and/or rolls, e.g., working rolls in a rolling stand, which are used for producing a rolled stock such as strips or slabs, wherein a liquid is sprayed onto the cylinders at high pressure through several nozzles.

Cylinder and/or rolls are used in numerous locations of a plant. Their surfaces become dirty and should be cleaned periodically or continuously.

Cleaning of rolling mill rolls with fluid sprayed at high pressure is known. JP-05 069 028A, JP-06 344 005A, JP-10 058 002A, JP-6 285 516, JP-09 262 607A, JP-08 155 509A, JP-08 174 005A, JP-07 068 301A, JP-05 042 309A, JP-05 317 907, JP-05 337 52A, and JP-58 199 604A, show corresponding installations.

EP 0385 097 A2 discloses that in rolling mill technology, wet skin-pass rolling is known, wherein with water or water-like additives, a sliding film is formed between working rolls and backup rolls. Simultaneously, the rolls should be kept clean.

U.S. Pat. No. 5,460,023 describes a method of and an apparatus for cleaning of rolls with a multiplicity of nozzles arranged on a nozzle beam. For a better cleaning of the entire surface of a roll, the nozzle beam is displaced axially. Thereby, each separate nozzle travels a predetermined path over the surface of a roll. Axial displacement of the nozzle beam is effected with a hydraulic cylinder.

EP 09 95 504 B1 discloses a method of cleaning cylinders and/or rolls in strip casting installations, rolling mills, and/or strip treating lines, in particular, skin-pass mills or similar after-treatment mills for producing or treatment of metal strips, according to which cylinders and/or rolls are subjected to cleaning fluid from at least one cleaning nozzle the distance of which from the cylinder surface or the roll surface of the concerned cylinder or roll is adjusted or controlled to a predetermined value, with the cleaning nozzle reciprocating with adjusted or controlled oscillating speed along the concerned cylinder and/or roll dependent on the strip speed and/or strip material and/or strip surface.

In known installations, one or several nozzles are displaced along the cylinder. Therefore, the nozzle or nozzles are arranged, e.g., on a traveling drive unit with slides, wherein each nozzle must be supplied with cleaning fluid by a displaceable supply-or feeding conduit. Further, a movable cabling is necessary. The regulation of the oscillating speed is expensive, as of the distance of nozzles from to-be-cleaned rolls.

Accordingly, an object of the invention is a method of and an apparatus for cleaning cylinders/rolls which simpler in operation and design, with increased cleaning effect and prevention of surfaces damages.

This object is achieved according to the invention, for the method with characterizing features of claim 1.

Advantageous embodiment of the invention are recited in dependent claims. The invention also relates to an apparatus for effecting the method.

Further embodiments of the apparatus follow from corresponding dependant claims.

The decisive advantage of the inventive method consists in that no mechanical movement in the roll longitudinal direction takes place and, therefore, no cable towing apparatus to supply conduits is needed. The electricity necessary for turning on and off the nozzle beam and switching on and off separate nozzles is reduced. During cleaning operation, the 100% of the circumference of the cylinder, or the roll is treated during a cleaning period, so that no dirty spirals appear.

Each cleaning period starts at the same cylinder or roll end, and the intervals between the cleaning periods are the same.

With a rotational angle of the nozzle of 17° and a circumference corresponding to the diameter of 60 mm, the necessary distance to the roll surface amounts to about 200 mm. If an effective diameter of 50 mm is used, with a maximum strip width of 2,100 mm, 42 nozzles are provided per nozzle beam. With a simultaneous activation of two nozzles with a single valve, 21 valves are required. In a preferred embodiment, the nozzles can be arranged with an offset. At a VE-water consumption of l/min per nozzle and a sequential control of respective two by two nozzles above the rolling stock and two by two nozzles beneath the rolling stock, the total volumetric flow amounts to about 90 l/min.

A cleaning period is determined by two revolution of the cylinder/roll per each nozzle pair, so that the nozzles (n) in the nozzle beam clean the cylinder roller at a second revolution and then are returned off, and the nozzles (n+1) start cleaning of the cylinder/roll during a first revolution. When the nozzles (n) are turned off, the nozzles (n+2) are turned on.

E.g., with a working roll diameter of 620 mm, the length of the rolling stock per nozzle sequence is about 4 m, at a diameter of 560 mm, 3.5 m, and at a diameter of 400 mm, about 3 m. At average roll speed of 100 m/min in a skin-pass stand, the operational period is about 2 sec/nozzle pair and for the entire roll 21+1 sec/roll. The total length of the rolled stock during cleaning is about 37 m.

Embodiments of the invention will be now described in detail with reference to schematic drawings.

The Drawings Show

FIG. 1 a timed course of the nozzle discharge, and

FIG. 2 a view of a spray picture.

FIG. 1 shows a timed course of nozzle discharge during cleaning of a cylinder/roll.

A rolled stock, e.g., a metal strip, with a width 2 has a left edge 3 and a right edge 4. A working roll 5 (see FIG. 2) has a length that is greater than a width of the metal strip so that the collar regions 6, 7 of the working roll have no contact with the metal strip 1. The working roll 5 has a left barrel border 8 and a right barrel border 9.

In the shown embodiment, firstly, a left nozzle D1 of the nozzle beam 10 (see (FIG. 2) opens at time t1. After a predetermined time period, at time t2, additionally, a nozzle D2, which is located rightwardly adjacent to the nozzle D1, opens. After a subsequent time period, at a time t3, the nozzle D1 is turned off, and the next following nozzle D3 opens. This process is repeated as long until the right barrel border 9 of the working roll 5 is reached. The next cleaning period can then follow immediately thereafter when the nozzle D1 opens and then the nozzle 2.

Dependent on the degree of contamination of the cylinders/rolls 5, the next cleaning period follows with a time delay. The delay can follow automatically and have the same time period. It is also contemplated to start the cleaning periods additionally or always manually.

FIG. 2 shows a nozzle beam 10 with ten nozzles (D1-D10). The spray picture 11 of the nozzle D1 overlaps the spray picture 12 of the nozzle D2 in a region 13. The following nozzles show the same overlap. To better form the overlaps, which determine the degree of cleaning of the cylinder/roll, the adjacent nozzles D1, D2, e.g., are arranged on the nozzle beam 10 with offset. Each nozzle D1 or each nozzle pair D1, D2 are controlled by a valve (not shown).

REFERENCE NUMERALS

• 1 Rolling stock/metal strip
• 2 Metal strip width
• 3 Left edge
• 4 Right edge
• 5 Working roll
• 6 Collar region
• 7 Collar region
• 8 Left barrel border
• 9 Right barrel border
• 10 Nozzle beam
• 11 Spray picture
• 12 Spray picture
• 13 Overlapping region
• D1-D10 Nozzles
• t1-tn time points

Claims

1. A method of cleaning cylinders (5) and/or rolls (5), e.g., working rolls (5) in a rolling stand, which are used for producing a rolled stock (1) such as strips or slabs, wherein a liquid is sprayed onto the cylinders (5) at high pressure through several nozzles D1-Dn, characterized in that a number of nozzles (D1-Dn) are stationary arranged in and/or on a nozzle beam (10), at least one on-off valve is associated with each nozzle (D1-Dn), and one or several nozzle(s) (D1-Dn) are sequentially switched on and off one after another, starting from one end of the nozzle beam.

2. A method according to claim 1, characterized in that at a time, one nozzle (D1-Dn) is switched on.

3. A method according to claim 1, characterized in that at a time, two adjacent nozzles (D1-Dn) are switched on.

4. A method according to claim 1, characterized in that upon reaching an opposite and of the cylinder/roll, the following cleaning period starts immediately.

5. A method according to claim 4, characterized in that the next cleaning period is carried out with a time delay.

6. A method according to claim 1, characterized in that the nozzles (D1-Dn) are switched on dependent on a roll speed.

7. An apparatus for cleaning cylinders and/or rolls, e.g., of working rolls in a rolling stand, which are used for producing a rolled stock such as strips or slabs, wherein several nozzles (D1-Dn) for spraying liquid at high pressure onto the cylinders (5) are provided, characterized in that at least one valve is associated with each nozzle (D1-Dn).

8. An apparatus according to claim 7, characterized in that the nozzle (D1-Dn) is a rotary nozzle.

9. An apparatus according to claim 7characterized in that the nozzle beam (10) is arranged above the rolled stock (1).

10. An apparatus according to claim 7characterized in that the nozzle beam (10) is arranged beneath the rolled stock (1).

11. An apparatus according claim 7characterized in that the nozzle beam (10) has a greater length as the cylinder or roll (5).

12. An apparatus according to claim 7characterized in that the nozzles (D1-Dn) are arranged with offset in two parallel rows.

13. An apparatus according to claim 7characterized in that supply of nozzles (D1-Dn) is carried out centrally through a fluid pressure conduit.

14. An apparatus according to claim 7characterized in that on the nozzle beam (10), cover devices are secured.

15. An apparatus according to claim 13, characterized in that several nozzles (D1-Dn), in particular arranged next to each other nozzles (D1-Dn), are brought in an open communication with the liquid pressure conduit by their associated valves at the same time.

16. An apparatus according to claim 7characterized by a control unit for periodical or sequential control of the valves according to the magnitude predetermined cleaning periods.

17. An apparatus according to claim 7, characterized by a control unit for periodical or sequential control of the valves dependent on the cylinder speed.