JPS624835A - Floating and supporting device for strip - Google Patents

Abstract

PURPOSE:To float and support a strip while correcting the deviation in the transverse direction by ejecting fluid from a floater right under the strip and blowing the fluid toward the top surface of the strip from a fluid injector disposed in the central part so as to face said floater. CONSTITUTION:The floater 11 is disposed right under the strip 1 and a pressure receiving surface 13 thereof is disposed to face the bottom surface of the strip 1. Slit nozzles 12, 12 are provided at both front and rear ends of the above- mentioned surface 13 in the arrow-marked passing direction of the strip 1 along the transverse direction of the strip 1. The fluid is injected respectively upward from the slits 12, 12 toward the bottom surface of the strip 1 to generate a static pressure between the strip 1 and the surface 13, thereby floating and supporting the strip 1. The fluid injector 20 is disposed above the floater 11 to face the central part of the surface 13 so the the fluid is blown to the central part in the transverse direction on the top surface of the strip 1. Both side ends of the strip 1 are thereby curved upward to generate the centering force toward the central part, by which the deviation in the transverse direction is automatically corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a floating support device that is attached to a continuous annealing furnace for strip plates such as steel strips and supports the strip plates in a non-contact manner during threading.

<Prior Art> As shown in FIG. 3, which shows the concept of a continuous annealing furnace conventionally used as processing equipment for metal strips such as cold-rolled steel strips, a cold-rolled steel strip 1 is heated through a payoff (not shown). It is fed out from a reel, passes through a cleaning tank, a looper, etc. (not shown), and is supplied to a continuous annealing furnace. A large number of helper rolls 2 are provided above and below in this continuous annealing furnace, and the strip 1 is wound around these helper rolls 2 and moves up and down inside the furnace to adjust the required mechanical properties according to the mechanical properties required for the product. When heated and cooled, it is given the necessary mechanical properties such as yield strength, tensile strength, and good deep drawability at room temperature. Note that the inside of the continuous annealing furnace is filled with a reducing gas such as hydrogen nitride gas to prevent surface oxidation of the strip 1.

Strip 1 is typically 850-900 in heating zone A.
It is heated by the radiant tube 3 to about ℃. After that, it is heated uniformly for several tens of seconds in a soaking zone B, and then cooled to 400 degrees Celsius at a cooling rate of 3 to 200 degrees per second by a gas jet in a rapid cooling zone C.
It is quenched to about 0.degree. C., then subjected to an overaging treatment at about 400.degree. C. for about 2 minutes in an overaging zone, and finally quenched to room temperature by a gas jet in a final quenching zone E.

By the way, in such a continuous annealing furnace, the overaging zone requires a long residence time of about 2 minutes, so in a large continuous annealing furnace, the overaging zone has a long furnace length of about 100 meters or more. The continuous annealing furnace as a whole is very long, over 150 meters. If this over-aging zone can be shortened, it is expected that a continuous annealing furnace can be manufactured in a shorter time and the construction cost of the equipment can be reduced. As a specific means for this, it has been found that the length of the overaging zone can be shortened by changing the material of the strip 1 and increasing its heating temperature higher than before.

However, when realizing such a furnace, if a high temperature strip is brought into contact with the roll, the strength of the strip is reduced, resulting in uneven contact with the cold roll or the roll surface with carbon, etc. attached in the rolling oil. Thermal deformation of the strip due to contact with the strip becomes a problem in threading. In addition, if the strip is run vertically as in the past, the high temperature will cause a creep phenomenon due to the strip's own weight, resulting in a narrowing of the width. It is necessary to run stably without causing any problems.

In this way, a floater that supports the strip in a non-contact manner has been developed in order to pass the strip over a long distance in the horizontal direction without causing it to sag, and this floater is used in color coating lines, for example. .

Figure 4 shows the concept of a floater installed in a continuous annealing furnace.
As shown in FIG. 5, which shows a cross-sectional view of the v-■ arrow, and FIG. 6, which shows a cross-sectional structure of the floater, a plurality of floaters 11 are provided directly under the running strip 1. They are arranged along the plate direction (right side in Figure 4). Each floater 11 has narrow slit nozzles 12 at both front and rear ends of the strip 1 in the threading direction, and these slit nozzles extend in the width direction of the strip l and face each other.
□It opens diagonally upward to the opposite side. Therefore, the gases such as hydrogen nitride ejected from these slit nozzles 12 collide with each other and their flow direction is suddenly changed, and this change in momentum creates a static gas pressure between the strip 1' and the pressure receiving surface 13 on the upper surface of the floater 11. A pressure is created to levitate and support the strip l. Note that the type of ejected gas is generally the same type as the atmospheric gas in the furnace. Also in the figure, 1
A plurality of strips 4 are provided above and below the strip 1.
15 is a radiant tube burner or a recuperator for preheating the intake air for combustion of the radiant tube, 1θ is a support for the radiant tube 14, 17 is a duct for supplying gas to the floater 11), 18 is a continuous annealing furnace This is the wall of the furnace.

(Problems to be Solved by the Invention) The floater U described above generates a uniform static pressure between the strip l and the pressure receiving surface 13 and supports the strip 1 in a floating manner. If the position of the strip 1 shifts in the width direction, there is no function to correct this. For this reason, there was a risk that an unexpected accident would occur in which the strip l would come into contact with the furnace wall during threading.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a floating support device having a function of correcting deviation in the width direction of a strip (band plate) supported by a floater, that is, a so-called centering function. purpose.

<Means for Solving the Problems> The flotation support device for a strip according to the present invention has a main body that is provided with a pressure receiving surface located directly below the strip and facing the lower surface of the strip in the strip threading direction. Openings are opened along the width direction of the strip at both front and rear ends, and fluid is ejected obliquely upward toward the lower surface of the strip to generate static pressure of the fluid between the strip and the pressure-receiving surface. A floater having a fluid spouting port formed therein; and a fluid injector disposed above the floater to face a central portion of the pressure receiving surface and spray fluid onto a widthwise central portion of the upper surface of the strip plate. It is characterized by

(Function) Fluid is ejected from the fluid spout facing the lower surface of the strip,
The strip plate is suspended and supported above the floater by the static pressure of the fluid generated on the pressure receiving surface. At the same time, the fluid sprayed from the fluid injector to the center in the width direction of the upper surface of the strip curves the strip above the floater into a shape in which both side edges are floated higher than the center, and Fluid pressure from the floater generates a centering force on the strip from both side edges toward the center.

<Example> Hereinafter, a floating support device for a band plate according to an example of the present invention will be described based on the drawings. Note that the same parts as those described above are given the same reference numerals and redundant explanations will be omitted.

Figure 1 is a plan view of the floating support device viewed from above, and Figures 2 (a) and (b) are II-I in Figure 1, respectively.
As shown in FIG. 0, which is a diagram illustrating the operation as viewed from arrow I, a fluid injector 20 is provided above the pressure receiving surface 13 of the floater 11 and facing the pressure receiving surface 13 with a gap through which the strip 1 passes. The fluid injector 20 and the floater 11 constitute a floating support device.

The fluid injector 20 is positioned so that its widthwise center coincides with the widthwise center of the floater 11, and the size of the fluid injector 20 is smaller than the width of the floater 11, and the strip 1 is positioned with its widthwise center aligned with the widthwise center of the floater 11. When the strip 1 is aligned with the widthwise center of the floater 11, the fluid supplied from an unillustrated source and injected downward from the fluid injector 20 applies pressure only to the widthwise center of the strip 1. It is designed to have a negative impact. Note that the fluid injector 20 may be integrally attached to the floater 11 using a frame or the like, but it is not necessary to make it an integral body in advance as long as it is installed so as to satisfy the above conditions.

As mentioned above, when the strip 1 is threaded in the direction of the arrow in FIG. 1 while being buoyantly supported by the floater 11, unlike the state shown by the solid line in FIG. 2 in which only the static pressure from the floater 11 acts, the main levitating support is In the device, the fluid pressure from the fluid injector 20 acts on the top surface of the strip 1, so that both edges of the strip 1, which are not affected by the fluid pressure from above, are not affected by the fluid pressure from above, as shown by the dotted line in FIG. It has a curved shape that is raised higher than the central part, which is affected by pressure. At this time, as shown in FIG. 2(a), if the widthwise center of the strip 1 and the widthwise center of the floater 11 coincide, the static pressure from the floater 11 will cause Centering forces Fl and F2 are generated at the edges, which have the same magnitude and act in opposite directions. On the other hand, as shown in FIG. 2(b), when the widthwise center of the strip 1 and the widthwise center of the floater 11 are misaligned, the side edge of the strip l on the side in the misalignment direction is on the other side. The floater 11 also receives a large static pressure from the side edge of the floater 11, and its centering force Fl' becomes larger than the centering force F2' on the other side.

Therefore, due to the difference between the centering forces F l' and F 2', the strip 1 receives a force for correcting the deviation, and automatically returns to a position where its widthwise center coincides with the widthwise center of the floater 11.

The floating support device of the present invention can be applied not only to continuous annealing furnaces but also to continuous galvanizing lines, colored iron plate coating lines, etc., and can also be applied to paper processing equipment by using the strip as a paper strip. Further, the fluid ejection opening of the floater may be formed by arranging a large number of circular hole nozzles in the width direction instead of the slit nozzle.

<Effects of the Invention> According to the floating support device of the present invention, it is possible to thread the strip while automatically centering the strip, thereby preventing an unexpected accident from occurring during threading of the strip. can.

[Brief explanation of drawings]

FIG. 1 is a plan view of a floating support device according to an embodiment of the present invention, FIGS.
FIG. 4 is a conceptual diagram of a continuous annealing furnace, FIG. 4 is a conceptual diagram of a floater installed in the continuous annealing furnace, FIG. 5 is a cross-sectional view taken along the line ■--■, and FIG. 6 is a cross-sectional view of the floater. In the drawings, 1 is a strip, 11 is a floater, 12 is a slit nozzle, 13 is a pressure receiving surface, and 20 is a fluid injector.

Claims (1)

[Claims] The main body is provided with a pressure-receiving surface located directly below the strip plate and facing the lower surface of the strip plate, and has openings along the strip width direction at both front and rear ends in the strip threading direction, and on the lower surface of the strip plate. a floater having fluid jet ports formed therein to generate static pressure of fluid between the strip plate and the pressure-receiving surface by jetting fluid diagonally upward toward the floater; A flotation support device for a strip, comprising: a fluid injector that is disposed to face each other and sprays a fluid onto a central portion of the upper surface of the strip in the width direction.