JPS6156294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the flow rate of cooling water jetted from a cooling header when cooling hot materials such as hot rolled steel materials.

The most fundamental thing to properly implement cooling control is to accurately grasp the jet flow rate of cooling water. As a means of measuring the flow rate, it is usually possible to measure the flow rate of the cooling water supplied to the header by installing a flowmeter in the cooling water supply pipe of the cooling header, but it is possible to measure the flow rate of the cooling water supplied to the header. In some cases, a larger amount of cooling water is supplied than the actual jet flow rate in order to maintain the flow rate, and the excess cooling water is returned to the water storage tank from the overflow passage 11 provided in the header 1 as shown in Figure 1. That's what I do.
Therefore, measuring the amount of cooling water supplied to the cooling header does not determine the actual flow rate;
For this reason, the actual ejection flow rate has not been accurately determined in the past.

An object of the present invention is to obtain a means that can grasp the actual flow rate of cooling water ejected from a cooling header and at the same time control this flow rate, thereby performing accurate cooling control.

In the present invention, focusing on the fact that there is a certain correlation between the internal pressure of the cooling header and the jetting flow rate,
The feature is that this characteristic is used to control the flow rate.

The configuration of the method of the present invention will be explained below with reference to FIG. In the method of the present invention, a pressure detector 2 for measuring the internal pressure of the cooling header 1 is first provided. As the pressure detector 2, a water level measuring method using a manometer as shown in FIG. 1 or a Bourdon tube type pressure gauge is used to capture the internal pressure of the header as a physical quantity. This physical displacement amount is converted into an electrical amount by the detection signal converter 3, and is input to the arithmetic circuit 4 as a pressure signal _P1 .

Between the internal pressure (P) of the header and the flow rate (Q),
It has been experimentally found that there is a certain correlation generally expressed as Q=(P). Therefore, the pressure/flow characteristics shown in FIG. 3 for a specific cooling header are obtained in advance by actual measurements.
These pressure/flow characteristics are stored in the memory 5.
The arithmetic circuit 4 extracts the memory characteristics, calculates the flow rate Q ₁ corresponding to the pressure detection pressure signal P ₁ from the detection signal converter 3, compares the set flow rate Q ₀ and the calculated flow rate Q ₁ , and calculates the error flow rate △Q ( =Q ₀ −Q ₁ ) is calculated.

On the other hand, a flow rate adjustment valve 7 is provided in a path for supplying cooling water from the cooling water supply device 6 to the cooling header 1, and the opening degree of this valve is adjusted by a servo motor 8. The servo motor 8 is operated by the flow rate error ΔQ output from the arithmetic circuit 4, and thereby adjusts the valve opening of the regulating valve 7 to control the flow rate supplied to the cooling header 1. Let's do it like this.

The relationship between header internal pressure and flow rate, which is the basic concept of the method of the present invention, shows some changes between the actual measurement results and the calculated values in the range of 1000 to 4000/min as shown in Figure 4. , this error is within the range of ±3%. Therefore, no inconvenience occurs in valve control based on calculation errors based on the characteristic curve (FIG. 3) obtained by actual measurements.

According to the present invention, it is possible to grasp the internal pressure of the cooling header, and at the same time, it is possible to control the flow rate by feeding back this signal based on the detected pressure value, making it possible to perform accurate cooling control and increase the water pressure. It can be effectively applied to lamina cooling headers where it is difficult to grasp the flow rate due to fluctuations.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a cooling header to which the method of the present invention is applied. FIG. 2 is a block diagram showing the structure of the method of the present invention. Figure 3 is a graph showing pressure/flow characteristics. FIG. 4 is a graph showing a comparison between the measured flow rate and the calculated flow rate. 1: Cooling header, 2: Pressure detector, 3: Detection signal converter, 4: Arithmetic circuit, 5: Pressure/flow characteristic memory, 6: Cooling water supply device, 7: Flow rate adjustment valve,
8: Servo motor.

Claims (1)

[Claims] 1. Detecting the ejection pressure in the cooling header as a physical quantity and converting it into an electrical signal, and actually measuring in advance the characteristics representing the relationship (Q = (P)) between the ejection pressure (P) and the cooling water flow rate (Q) in the cooling header. death,
The results are stored in a memory, the stored characteristic values are retrieved and compared with the detected pressure value to calculate the corresponding cooling water flow rate, and the set flow rate and the calculated flow rate are compared to generate an error signal. A cooling water flow rate control method comprising: calculating the error signal; and adjusting the opening degree of a flow rate regulating valve provided between a cooling water supply device and a cooling header based on the error signal.