DE19702718C1 - Cooling medium control in a continuous casting installation - Google Patents

Abstract

The rate of cooling medium delivery is varied by switching on or off nozzles (8) on nozzle bars of individual cooling zones making up the cooling section. Several such bars within each zone are selectively chosen to form at least two spray groups (6-6", 7-7") which are alternately switched off and on for a specified time interval when the system pressure falls below a specified value. Switching takes place by means of a control valve (12) which is located at the branch point of the distributer pipes leading to the spray groups.

Description

The invention relates to a method for cooling medium control in a Continuous caster according to the preamble of claim 1.

The device arranged in the known continuous casting plants Coolant control has at least two tasks.

• 1. Cooling of the continuous strand
• 2. Cooling of the guide rollers and other machine parts

The nozzles give the cooling medium, mainly water over a large part of the Length of the cooling section through the spaces between the guide rollers the strand on and are summarized for gradation reasons to spray zones, the independently of each other with different amounts of the cooling medium can be.

The reasons for using different amounts of cooling, in particular Amounts of water are as follows:

• 1. For product quality reasons are for different grades different amounts of water required, some grades require a lot and others tolerate little splash water.  
• 2. In addition, in most systems the water quantities change with the Casting speed, d. H. at high casting speed is a lot and at low pouring speed requires little splash water.

The specific values of the spray nozzles used (nozzle characteristics) and the Splash water system designs make this technically necessary Change of water quantities, however, narrow limits:

• - The maximum amount of water in the nozzles is determined by the maximum possible Water form specified, the i. d. Usually at 7 bar and from the pipe system as well as the pumps is determined.
• - The minimum amount of water is required to maintain the correct Spray pattern of the nozzle required minimum pressure specified, which at about 1 bar lies.

The resulting bandwidth between the largest and smallest possible The amount of water is from the application technology in most continuous casting plants too narrow, so that it is too, especially with the small amounts of water unsatisfactory compromise.

From DE-AS 15 58 329 is a device for cooling water control at one Continuous casting plant known, in the below the continuous casting mold in one Cooling section several cooling water spray nozzles arranged at a distance from one another are directed towards the downward moving cast strand. The cooling water jets the nozzles are adjustable via valves. The valves are driven by one Control device connected by means of a pulse counter and a this coupled and responsive to the cast strand movement pulse generator Spray nozzles can be switched on and off in succession.

EP 0 028 686 A1 describes a device for cooling in particular block and Stick strands revealed. So-called are along the surface of the strand Spray bars as supports for spray pipes or nozzles relative to the surface of the strand adjustable. This is an adaptation of the fan-like Cooling water jets possible on changing strand widths and thicknesses.

The object of the invention is to provide a method for cooling medium control in a Continuous caster to specify the range of different amounts of Cooling medium, especially with regard to smaller quantities, can be widened.

This object is achieved with the in the characterizing part of claim 1 specified features solved. Advantageous further developments and a device to carry out the process are part of subclaims.

The essence of the invention is the combination of several spray battens within a spray zone to a spray group and the alternate switching on and off of the individual groups when the system pressure falls below a specified level Cooling medium. The individual groups are activated when For example, the system pressure for the cooling medium has dropped below 1 bar. The Time interval for the change between the individual groups is expediently between 5 and 40 seconds. A symmetrical division of the Groups arise when the spray battens in a zone are in Pulling direction of the strand seen, consecutively viewed as numbered and the spray battens with the even and those with the odd numbers a spray group are summarized. Through this procedure it is possible that even if the system pressure falls below all Guide rollers and the other machine parts are cooled on all sides and that only half or, for example, a third of the existing spray nozzles with the Cooling medium is applied so that the previously minimal amount of cooling medium Zone can be reduced again to half or a third.

In order to be able to carry out the described method, the is in the fork a control valve is arranged in the individual groups leading distribution pipes. This Control valve is time-controllable and at a predetermined system pressure Coolant accessible.

In the single figure, a device according to the invention is shown in a schematic diagram. Shown is a section of a cooling section of a continuous caster, not shown, with guide rollers 2 , 3 arranged in a strand guide segment 1 , 1 ', between which the strand 4 is drawn off in the direction of arrow 5 . Spray battens 6 , 6 ', 6 ''and 7 , 7 ', 7 '' are arranged parallel to the guide rollers 2 , 3 and are each provided with a spray nozzle 8 at the open end. The individual spray battens 6-6 '', 7-7 '' are connected to manifolds 9 , 10 , several spray battens 6-6 '' or 7-7 '' being combined into a spray group within a cooling zone. In the fork from the main feed pipe 11 to the distributor pipes 9 , 10 , a control valve 12 , not shown, is arranged according to the invention. This control valve 12 is time-controllable and responsive to a system pressure of the cooling medium.

Claims (6)

1. A method for cooling medium control in the cooling section of a continuous casting plant, in which the nozzles arranged on spray bars of a cooling zone of the entire cooling zone can be switched on and off in order to increase or reduce the amount of cooling medium, characterized in that several spray bars are selectively selected and at least one within a zone two spray groups are combined and the individual groups can be switched on and off alternately at a defined time interval if the system medium falls below a specified system pressure. 2. The method according to claim 1, characterized, that the system pressure is at least 1 bar. 3. The method according to claims 1 and 2, characterized, that the time interval is between 5 and 40 seconds. 4. The method according to any one of claims 1 to 3, characterized, that the spray battens located in a zone are seen in the withdrawal direction are regarded as consecutively numbered and the spray battens with the even and those with the odd numbers to one spray group each are summarized.   5. Apparatus for carrying out the method according to claim 1 with beneath the continuous casting mold in a cooling section provided with guide rollers parallel to the guide rollers and spaced apart from one another by spray bars which each have an spray nozzle at the open end and are connected to a distributor pipe and in the withdrawal direction of the strand seen several selectively selected spray bars within a zone are combined to form a spray group, characterized in that a control valve ( 12 ) is arranged in the fork of the distributor pipes leading to the individual groups of spray bars ( 6-6 '' or 7-7 '') is. 6. The device according to claim 5, characterized in that the control valve ( 12 ) is time-controllable and responsive to a system pressure of the cooling medium.