JPH04198424A - Method of jet stream type heating/cooling control - Google Patents

Abstract

PURPOSE:To obtain control of the heat transfer rate easily and accurately without over-increasing capacity of fun and driving motor by making dimension of the nozzle opening part of blowing gas as variable state and controlling the relevant dimension of opening corresponding to the objective heat transfer rate. CONSTITUTION:The control of the gas flow rate blowing against the carry steel strip 1 is carried out by controlling opening width b of the nozzle 7A. The nozzle 7A is formed so as to be inserted between the width direction from gas supply side (air chamber 6 side) to gas blow out side. Out side of the nozzle 7A is pressed to innerside face of the guideblock 10. The wedge shaped holes 12 are formed into the guideblock 10 so that the inner face is connected to outside face of the blowing nozzle 7A. The opening width (b) of nozzle 7A is varied by vertically moving the guideblock 10 against exhausting direction of the blowing nozzle 7A.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a heating/cooling control method, and in particular, to a method of controlling heating/cooling by spraying gas from a nozzle opening onto a heating/cooling target to control the heat transfer coefficient between the target and the sprayed gas. The present invention relates to a jet heating/cooling control method using, for example, a cass jet or air jet type, for controlling the temperature of the object.

[Conventional technology]

In general, when heating or cooling a subject to be heated or cooled, for example, in a line that processes strips, heating or cooling curves (heat pattern ), it is necessary to control the amount of heat input and heat removed from the strip. There is a so-called jet heating/cooling control technology that controls the heating/cooling of the strip by controlling the amount of heat input/extraction by spraying scum or air (hereinafter collectively referred to as scum) from a nozzle onto the strip. . In a so-called jet heating/cooling control device that uses such technology, the amount of heat input and heat removal is controlled by - numerically, spraying changes the speed of the waste, and spraying changes the speed between the strip and the waste. This was done by controlling the heat transfer coefficient. Here, an example of a conventional configuration of a jet type heating/cooling control device is shown in FIG. In FIG. 5, the force 2 that has not been heated in the waste heating section 5 is passed through a duct 8 by a blower fan 3 into a wind box (chamber) 6.
sent to. The waste 2 that is not sent is sludged by the nozzle 7.
- sprayed on lip 1; Note that the blower fan 3 is driven by a drive motor 4. In this way, the sludge 1 to the slip 1 are heated by the sprayed dregs 2. Further, when constructing an apparatus for cooling the strip 1, a cassette cooler is used in place of the scum heating section 5, and the strip 1 is cooled with the same structure and operation as in the case of heating. Conventionally, the drive motor 4 of the blower fan 3 has a variable speed, and the rotational speed of the fan 3, that is, the blower fan drive motor 4, has been changed in order to blow at a speed at which the target heat transfer coefficient is obtained.
controlled the speed of. More specifically, a pressure gauge 9 is attached to the chamber 6,
Based on the pressure detected by the pressure gauge 9, the rotation speed of the motor 4 is controlled so that the internal pressure P of the chamber 6 reaches the target value. He was controlling V. Theoretically, the waste blowing speed (2) is proportional to the square root of the nozzle source pressure (-the pressure inside the chamber 6) P. Conversely, the chamber 6 internal pressure P is equal to 2 of the waste blowing speed V.
Proportional to the power. Further, the nozzle blowing air iQ is proportional to the blowing speed y. On the other hand, the energy 4E for driving the fan 3 is proportional to the pressure P×air volume Q. These relationships can be expressed as equations (1) to (3) below. E cost PXQ...(1) P txv ''-< 2) Q cx: v...(3) If we substitute equations (2) and (3) into equation (1), we get equation (4). Ecx:v''-(4) In other words, the driving energy E of the fan 3 is the gas blowing speed V
It is proportional to the third power of

[Problem to be solved by the invention] Normally, the fan and drive motor are selected according to the maximum value of the heat transfer coefficient control range. When the value was large, it was necessary to select a motor with a considerably large capacity. Therefore, there are problems in that the structure of the drive section requires a large installation space and is expensive. To address these problems, it is conceivable that in jet heating/cooling technology, parameters other than speed may be controlled for waste spraying with respect to heat transfer coefficient. The parameters for this heat transfer coefficient include, in addition to the speed of the dregs blowing,
It is known that the spraying depends on the nozzle pitch, the nozzle opening area, the distance between the nozzle and the strip, and the fluid characteristics. Among other parameters, changing the nozzle pitch for spraying is expected to be difficult due to the machine configuration. or,
When spraying, changing the distance between the nozzle and the strip (for example, as disclosed in Japanese Patent Publication No. 60-5621.7) is recommended, as spraying from a nozzle may cause the strip to flap due to debris, so There are disadvantages such as not being able to get close to it. Furthermore, in spraying, it is quite difficult to utilize fluid properties for control. Therefore, conventionally, there is no technology that can provide a sufficient solution to the above-mentioned problems. The present invention has been made in order to solve the above-mentioned conventional problems, and provides a jet type heating system that can easily and accurately control the heat transfer coefficient without increasing the capacity of the blower fan and drive motor.・The objective is to provide a cooling control method. [Means for Solving the Problems] The present invention sprays gas from a nozzle opening onto a heating/cooling control target, and controls the heat transfer coefficient between the target and the gas. In the jet heating/cooling control method for controlling the temperature of the object, the above problem is solved by making the size of the nozzle opening variable and controlling the opening size according to the target heat transfer coefficient. be.

[Effect]

The inventors have determined that, as control parameters for heat transfer coefficient control, spraying is controlled by other factors such as speed, for example, spraying is nozzle pitch, spraying is nozzle opening area, spraying is the distance between nozzles and strips, and spraying is various fluid properties. As a result of the study, as mentioned above, various problems arise regarding the nozzle pitch for spraying, the distance between the nozzle and the strip for spraying, and the fluid characteristics for spraying, so we considered controlling spraying by the nozzle opening area. Therefore, as schematically shown in FIG. 1, a nozzle (referred to as a slit nozzle) 7 in which the length in the longitudinal direction of the opening is constant and the length in the width direction (nozzle opening width) b can be controlled.
From A, investigate the relationship between the change in the heat transfer coefficient and the nozzle blowing speed (2) when the waste is sprayed toward the heating/cooling controlled object 1 and the nozzle opening width is varied. An example of this relationship is shown in Figure 2. In this case, the first
(A) in the figure is a side view of the nozzle 7A, and FIG. 1 (B) is a plan view, and the distance S between each blowing nozzle 7A is 500rn.
rn, the distance from the nozzle opening end to the WIJ object l is 150IIITI, and the temperature T of the heating/cooling control object is 200°C. Now, nozzle opening width b = 2nun, blowing speed 42mrI
l/second nitrite, % (x a rate halo 0 kcal/
Suppose that the operation is performed at m'-°C, that is, at the point indicated by the symbol A in FIG. The control target, for example, the strip 10 conditions (material, plate thickness, etc.) changes, and then the heat transfer coefficient changes to 102k.
Assume that cal/m ・h "・°C is required. At this time, if the nozzle opening width is changed to 7 mm, the operating point will move to the point indicated by the symbol B in the figure, and the desired heat transfer coefficient will be 10.
It is possible to achieve 2 kcal/m-hr-'C. At this time, the fan rotation speed is controlled so as not to change the waste blowing speed■, but if the fan rotation speed is not controlled, the wind speed will drop slightly, so this reduction in wind speed must be compensated for. If possible, widen the nozzle opening width a little further. The energy required to drive the fan -'F'E is proportional to the airflow iQ, as shown in equation (1) above, and this airflow Q is equal to the nozzle 7
If the longitudinal length of the opening of A is constant, the nozzle opening @
Since it is proportional to b, the energy E is proportional to the nozzle opening width as shown in equation (5). EoCb...(5) Therefore, when the operating point moves from point A to point B in Figure 2, the fan drive energy is 7 nun/2 nun
-3,50 times. On the other hand, in the conventional heat transfer coefficient control using the waste blowing speed V, the nozzle blowing speed ■ is changed from 42 m/s to 80 m/s.
/second, the operating point is moved to point C in the diagram to achieve the target. At this time, as shown in equation (4) above, the fan drive energy E is proportional to the cube of the wind speed ■, so when the operating point is moved from point A to point C, (80
11/second)/(4:17 seconds) to the third power, it becomes 6.91 times. From the above, in the method of the present invention, compared to the conventional method, the drive capacity of the fan only needs to be 3.5/6.91=1/2 to achieve the same heat transfer coefficient6. ,
Less drive energy E is required to achieve the same heat transfer coefficient, and the capacity of the fan and drive motor can be reduced. Therefore, it is possible to prevent the capacity of the blower fan and drive motor from becoming excessive when the control parameter for the heat transfer coefficient is set to the blowing speed, and to control the heat transfer coefficient easily and with high accuracy. do. Therefore, since the drive motor and the like are made smaller, the installation position of the device can be easily selected. Moreover, the device configuration becomes inexpensive.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. This embodiment is an apparatus having a configuration as shown in FIG. 3, which sprays waste onto an object to be heated and cooled, for example, a strip 1, thereby heating and cooling the strip 1. As shown in FIG. 3, this embodiment apparatus controls the flow rate Q of the gas to be blown onto the strip 1 being conveyed in the direction of the arrow in FIG. 3 by controlling the opening width of the nozzle 7A. This is done by The details of each spray nozzle (slit nozzle) 7A are shown in FIG. This Fig. 4 is a cross-sectional view of the spray nozzle 7A seen from the longitudinal direction, and the nozzle 7A is formed so as to narrow in the width direction of the nozzle 7A from the waste supply side (wind box 6 side) to the waste ejection side. The cross-sectional shape has a slit shape similarly formed in the longitudinal direction. Note that this nozzle 7A has an elastic force in the direction in which the waste spouting side spreads, and presses the outer surface of the nozzle 7A against the inner surface of the kite block 1°. The kite block 10 has a wedge-shaped hole such that its inner surface abuts the outer surface of the spray nozzle 7A]
2 is formed. When the kite block 10 is moved up and down in the jetting direction of the nozzle 7A, the opening width of the nozzle 7A changes. That is, if the kite block is pushed toward the original direction of the nozzle 7A, the opening width becomes smaller, and conversely, if the kite block is pushed back in the jetting direction, the opening width becomes larger due to the presence of elasticity. Further, in the kite block 10, all the spraying from the wind box 6 is carried out through the wedge-shaped holes 12 corresponding to the individual nozzles 7A.
is formed, and the guide block 10 is provided for each wind box 6, and this kite block 10 has a
Push-in cylinders 11 are provided at both ends of the kite block 11, and the kite block 0 can be moved up and down by the push-in cylinders 11- to control the width of the opening to the noil 7 for each spray. The structure of the song is the same as that of the conventional heating/cooling control device shown in FIG. 5 mentioned above, so similar parts are given the same numbers and the explanation thereof will be omitted. Next, the operation of the embodiment will be explained. In this embodiment, the heating and cooling of the strip 1 is controlled using, for example, the relationship between the nozzle opening width and the heat transfer coefficient as shown in FIG. 2 above. For example, if the nozzle opening width is b-2 mm and the waste blowing speed V is 42 m/sec, the heat transfer coefficient is 60 kca.
It is assumed that the operation is performed at l/m·hr-'C1, that is, at point A in the figure. In this case, the strip conditions are changed and then the heat transfer coefficient is 102 kcal/In2- agt -°C.
Assume that it has become necessary. In order to achieve this heat transfer coefficient, the guide block 1 is
0 toward the waste blowing direction, and open the nozzle @
Change (enlarge) b to 7111111. Thereby, the operating point can be moved to the point B in the figure, and the target heat transfer coefficient can be achieved. In addition, in the above embodiment, the nozzle opening size was made variable in the configuration using the kite block 10 etc. as shown in FIGS. The method is not limited to this method, and other methods can be used as long as the nozzle opening size can be controlled. Further, the shape of the nozzle opening is not limited to the slit shape, and the present invention can be practiced in other cases having a polygonal opening. Furthermore, in the above embodiment, heating and cooling control is not performed according to the operating conditions shown in FIG. 2, but the relationship shown in FIG. It is possible to find various relationships through operations, experiments, etc., and use those relationships in operations.

【Effect of the invention】

As explained above, according to the present invention, it is possible to easily and accurately control the heat transfer coefficient without increasing the capacity of the blower fan and the drive motor. Therefore, an excellent effect can be obtained in that the device configuration can be made smaller, flexibility in the installation location can be ensured, and the device can be made inexpensive.

[Brief explanation of the drawing]

FIGS. 1(A) and (B) are a side view and a plan view schematically showing the nozzle arrangement state for explaining the present invention in detail, and FIG. 2 similarly shows the nozzle opening width as a parameter. did,
FIG. 3 is a diagram showing an example of change in heat transfer coefficient with respect to gas flow rate; FIG. The figure is a cross-sectional view showing the detailed structure of the spray nozzle in the apparatus of the embodiment, and FIG. 5 is a cross-sectional view showing an example of the structure of a conventional heating/cooling control device. 1...Strip (heating/cooling control target), 2...
Spraying waste, 3...Blower fan, 4...Fan drive motor, 5...Scatter heating section (or waste cooler) 6...Wind box (chamber), 7A...Nozzle, 8...・Takt, 10... Guide block, 11... Push-in sill, 12... Wedge-shaped hole.

Claims (1)

[Claims] (1) A jet type that controls the temperature of a heating/cooling target by blowing gas from the nozzle opening and controlling the heat transfer coefficient between the target and the blown gas. A jet flow type heating/cooling control method, characterized in that the size of a nozzle opening is made variable, and the size of the opening is controlled according to a target heat transfer coefficient.