DE102011104735A1 - Method and device for cooling a work roll - Google Patents

Abstract

The invention relates to a method and a device for cooling a work roll during rolling for the production of strip-shaped material, a coolant being applied to the roll circumference. The method is characterized in that the coolant is applied tangentially to the roll surface against the direction of rotation of the work roll and, in the direction of rotation of the work roll behind the application area of the coolant, the coolant carried along by the drag effect and the dynamic pressure in the application area on the work roll butting surface is stripped off and into the Application area is pushed back. The device relates to the nozzle design for applying the coolant.

Description

The invention relates to a method and a device for cooling a work roll according to the preamble of claim 1 or 2.

• a) auf die Anwendung der Zwangskonvektion oder
• b) auf die Einstellbarkeit des Spalts zwischen der Arbeitswalze und einer Kühlschale.

In the prior art, flow cooling systems are described in which water or a coolant is passed between a cooling shell and a roller. The remarks relate to:

• (a) the application of forced convection or
• b) the adjustability of the gap between the work roll and a cooling shell.

Examples of this are from the JP 3161105 A , of the JP 6015313 A , of the DE 3616070 C2 or the EP 998 993 B2 known.

It should be explained that work rolls have a Abschliffbereich and thus the cooling shells must adapt to the curvature of the work rolls in order to achieve a sufficient cooling effect. An essential prerequisite for a sufficient cooling effect is compliance with a gap range for a given volume flow of coolant.

The gap and the volume flow cause a corresponding speed of the coolant. The highest possible relative speed is achieved by the coolant flowing counter to the direction of the working roller rotation. The flow velocity has a significant influence on the cooling effect and thus on the heat transfer coefficient.

The invention has for its object to improve the cooling effect on the roller.

This object is achieved according to the invention by a method for cooling a work roll during rolling for the production of strip-like material, wherein a coolant is applied to the roll circumference, characterized in that the coolant is applied counter to the direction of rotation of the work roll tangentially to the roll surface and in the direction of rotation the work roll behind the application area of the coolant is stripped by sealing means by the dragging action and the dynamic pressure in the application area on the work roll surface entrained coolant and pushed back into the application area.

• – dass die Düse durch eine Kühlschale gebildet wird, die einen Düseneintritt und einen Düsenaustritt aufweist,
• – dass die Strömung innerhalb der Düse zwischen dem Düseneintritt und dem Düsenaustritt um einen Winkel α derart umgelenkt ist, dass der Düsenaustritt im Wesentlichen tangential zur Arbeitswalzenoberfläche verläuft, wobei der Winkel α durch die Tangente an die Arbeitswalzenoberfläche im Bereich des Düsenaustritts und die Seelenlinie durch den Düseneintritt gebildet wird, und
• – dass sich die lichte Weite der Düse nach der Umlenkung bis zum Düsenaustritt verringert,

To carry out the method, a device is used for cooling a work roll in a roll stand, which extends over a partial circumference of the work roll and the bale length and by means of a coolant on the roll surface aufgebbar and arranged by a remote location, the impact of the coolant on the Rolling Well largely preventing, scraper is removable from this, which is characterized

• The nozzle is formed by a cooling shell having a nozzle inlet and a nozzle outlet,
• - That the flow is deflected within the nozzle between the nozzle inlet and the nozzle outlet by an angle α such that the nozzle exit is substantially tangent to the work roll surface, wherein the angle α through the tangent to the work roll surface in the region of the nozzle exit and the soul line through the Nozzle entry is formed, and
• That the clear width of the nozzle decreases after the deflection up to the nozzle exit,

Preferably, the clear width of the nozzle in the region of the deflection has an outer radius and an inner radius, wherein the outer radius is greater than the inner radius.

The cooling shell extends beyond the nozzle outlet over a portion of the work roll in the direction of scrapers, the cooling shell according to a further embodiment of the invention at the end facing away from the nozzle inlet has a pivot point with which the gap between the cooling shell and work roll surface after the nozzle exit is adjustable.

Further embodiments will become apparent from the dependent claims and are described below with reference to the drawings.

The invention will be explained below with reference to the drawings.

Showing:

1 schematically the device according to the invention for cooling,

2 - 4 various sealing possibilities of the outside of the nozzle relative to the work roll surface.

To a directed flow in the gap 5 To achieve this, it is necessary that the coolant is introduced into this gap accordingly. For this purpose, a nozzle is necessary, the volume flow of the coolant as tangential as possible in the gap 5 introduces. Characteristic of a nozzle 3 is that it narrows the volume flow over its length and thus increases the flow rate. In conjunction with the gap 5 the volume flow must overcome a system-related pressure resistance. The flow resistance in the gap 5 and the dragging action of the work roll surface 10 cause a significant part of the volume flow of the coolant (studies showed rates between 8 and 20%) through the gap 14 be discharged. This means that this volume flow is lost for the cooling of the work roll. It should be noted here that the roller is to be cooled as close as possible to the nip outlet. It should be achieved that as little heat penetrates into the roller and thus the average roller temperature remains low. A seal 2 prevents the escape of a volume flow between the work roll 10 and the outer part of the nozzle 13 flows. By combining a nozzle, the coolant is as tangential as possible in the gap 5 leads, and the seal 2 A method is presented which provides the complete volume flow for the cooling of the work roll. As a result, the work roll can be optimally cooled without loss and energetically.

A nozzle 3 , which satisfies the claims according to the method described above, has an angle α, which is at least 60 ° and a maximum of 120 °.

In order to meet the environmental conditions in a roll stand, the angle α is preferably between 80 ° and 100 °. The angle α is formed by the tangent 7 ' and the soul line 7 , So the tangent to the work roll surface in the region of the nozzle exit and the soul line through the nozzle inlet.

The environmental conditions in a rolling mill are determined by the back-up roll 1 , the working roller 10 , the scraper 11 , the work roll chocks (not shown) etc .. They give the limits for the space supply of a shell cooling consisting of nozzles 3 and cooling shells 6 in front.

The nozzle shown 3 is preferably in the cooling shell 6 integrated. The cooling shell 6 owns a fulcrum 8th which is connected to a mechanism, not shown. This mechanism is connected to at least one further cooling shell (not shown). She leads the gap 5 until the scraper 11 continued.

A gap 5 with the size h is a necessary condition for a functioning flow or shell cooling. The fulfillment of this condition is not sufficient, it must be through the described nozzle 3 with seal 2 be supplemented to form a functional work roll cooling can.

The nozzle 3 is formed by a nozzle inlet 3 ' and a nozzle exit 3 '' , It preferably extends over the entire bale length of the work roll 10 , At a minimum, the nozzle or a series of similar nozzles covers the bale length of the work roll 10 about the bale length corresponding to the maximum metal band width +50 mm. The described nozzle 3 tapers from the nozzle inlet 3 ' to the nozzle exit 3 '' with simultaneous flow deflection by the angle α. In this case, the nozzle is designed such that it has an outer radius R and an inner radius r. The outer radius R is greater than the inner radius r. The largest compression of the stream threads takes place after the flow deflection. This ensures that the pressure loss is minimized. At the nozzle exit, the cooling medium preferably meets tangentially (according to the tangent 7 ' ) on the stripper 10 , Because the working roll diameter can vary and the curvature of the cooling shell 6 fix, the flow can be +/- 10 ° from the ideal tangent 7 ' deviating on the work roll 10 to meet.

As already described, is then with a flow in Arbeitswalzendrehrichtung 21 to count. This flow is missing for cooling the work roll 10 , It is referred to below as loss flow. The lost flow tries through the gap 14 to escape. sealing elements 15 respectively. 18 This can prevent this and ensure that the complete volume flow is available for cooling.

The pretensioning elements 16 respectively. 19 counteract the momentum and pressure of the leakage flow and thus guarantee the tightness. The fastener 17 and the case 20 ensure a secure grip and protection. The seal can be done both mechanically and hydraulically or pneumatically.

Another possibility is in 4 shown.

Here is a sealing medium such. B. water with overpressure in the gap 4 pressed. The medium is distributed via a distributor 23 and a feeder 24 promoted to the sealing point.

LIST OF REFERENCE NUMBERS

1

supporting roll

2

seal

3

jet

3 '

nozzle inlet

3

nozzle exit

4

Streams of coolant

5

Gap with the size h

6

cooling tray

7

Spirit line that intersects with the tangent

7 '

Tangent, with which the nozzle the coolant in the gap 5 splashes

8th

Fulcrum for nozzle and cooling shell

9

Movement possibility of the nozzle / cooling shell

10

Stripper

11

scraper

12

rolling

13

Outer part of the nozzles

14

Gap between nozzle and work roll

15

sealing element

16

biasing member

17

fasteners

18

sealing element

19

biasing member

20

casing

21

direction of rotation

22

sealing medium

23

Distributor of the sealing medium

24

feed

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 3161105 A [0003]
• JP 6015313 A [0003]
• DE 3616070 C2 [0003]
• EP 998993 B2 [0003]

Claims (10)

A method for cooling a work roll during rolling for the production of strip-like material, wherein a coolant is applied to the roll periphery, characterized in that the coolant is applied against the direction of rotation of the work roll tangentially to the roll surface and in the direction of rotation of the work roll behind the application region of the coolant Stripped by the drag and the back pressure in the application area on the work roll surface coolant is pressed by sealing means and pressed back into the application area. Device for cooling a work roll ( 10 ) in a roll stand which extends over a partial circumference of the work roll ( 10 ) and the bale length extends and by means of a coolant on the roll surface aufgebbar and arranged by a remote location, the impact of the coolant to be rolled ( 12 ) largely preventing, scrapers ( 11 ) is removable from this, characterized in that - a nozzle ( 3 ) is formed by a cooling shell, which enters a nozzle ( 3 ' ) and a nozzle outlet ( 3 '' ), that the flow within the nozzle between the nozzle inlet ( 3 ' ) and the nozzle exit ( 3 '' ) is deflected by an angle α such that the nozzle outlet ( 3 '' ) is substantially tangential to the work roll surface, wherein the angle α is formed by the tangent to the work roll surface in the region of the nozzle exit and the soul line through the nozzle inlet, and - that the inside diameter of the nozzle decreases after the deflection to the nozzle exit, Apparatus according to claim 2, characterized in that the inside diameter of the nozzle ( 3 ) has an outer radius and an inner radius in the region of the deflection, wherein the outer radius is greater than the inner radius. Device according to one of the preceding claims, characterized in that the angle α and at least 60 ° and a maximum of 120 °. Apparatus according to claim 4, characterized in that the angle α is between 80 ° and 100 °. Device according to one of the preceding claims, characterized in that the cooling shell ( 6 ) over the nozzle outlet ( 3 '' ) with the work roll surface forming a gap (h) over a portion of the work roll ( 10 ) in the direction of the scraper ( 11 ). Device according to one of the preceding claims, characterized in that the cooling shell ( 6 ) of the nozzle at the nozzle inlet ( 3 ' ) facing away from a pivot point ( 8th ), with which the gap (h) between cooling shell ( 6 ) and work roll surface after the nozzle exit ( 3 '' ) is adjustable. Device according to one of the preceding claims, characterized in that the nozzle consists of a single nozzle which extends over the entire length of the bale of the work roll or is formed of a plurality of juxtaposed similar nozzles. Device according to one of the preceding claims, characterized in that on the outer part ( 13 ) of the nozzle ( 3 ) on the work roll surface adjacent, in particular prestressed, sealing elements ( 15 respectively. 18 ) are provided. Device according to one of the preceding claims, characterized in that on the outer part ( 13 ) of the nozzle these sealing against the surface of the work roll sealing, hydraulically or pneumatically acting, sealing elements ( 22 - 24 ) are provided.

Images