JPH04280761A - Static pressure pad for gas flow control - Google Patents

Abstract

PURPOSE:To suppress the inflow of a discharge fluid and reduce the effect to the furnace belt atmospheric temperature by slantly forming a slit on one side along the running line of a thin plate at the angle toward the inside of a pad, and slantly forming the angle of a slit on the opposite side against the thin plate face nearly perpendicular or outward. CONSTITUTION:A pair of static pressure pads 2 are arranged at symmetrical positions across a strip 1, gas is blown into a pad main body 3 from a feed section 4 and spouted from slits 6 formed on a plate section 5, and the strip 1 is kept in the noncontact state. The spout angles of the slits 6 are properly selected to control the discharge gas flow. The slit 6a on one side is slantly formed at the angle theta1 toward the inside of the pads 2, and the angle of the slit 6b on the opposite side is slantly formed at least nearly perpendicular or outward from the pads 2. The gas flow spouting from the slits 6 is controlled, and the adverse effect to the strip annealing line can be sharply reduced.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a static pressure pad that holds a strip-shaped thin plate such as a thin steel plate in a non-contact state when the plate is passed through the plate. This relates to static pressure pads that can be used.

0002

2. Description of the Related Art For example, in a heat treatment process such as annealing of steel strip or in a continuous hot-dip plating line, if a roll or the like is directly brought into contact with the strip to hold and pass the strip, the surface properties of the strip may deteriorate. For this reason, a method of holding the strip in a non-contact state can be considered, but
As one means for achieving this, a static pressure pad (cushion) that utilizes fluid static pressure is known. Conventionally, static pressure pads have been used to stably hold strip-shaped thin plates in a non-contact state.
For example, the structure shown in Japanese Unexamined Patent Publication No. 57-79164 is common.

That is, as shown in FIG. 2, this conventional pad is a pair of box-shaped pads 11 arranged symmetrically across the running line of the thin plate S, and the surface facing the thin plate holds the thin plate S. Slit 12 for fluid ejection
is formed. The fluid ejection slit 12 generates static pressure between the pad and the thin plate, and its shape,
Various arrangements have been proposed.

As a typical slit, when the ejection angle of the slit 12 of the static pressure pad 11 with respect to the thin plate S is viewed in the running line direction, the slits 12 on both sides of each pad are symmetrical to each other as shown in the figure. Most of them were formed facing toward the direction (or vertically). With such a slit, most of the ejected gas usually flows toward the outside of the pad along the plate after colliding with the thin plate, as shown by the arrow.

[0005]

However, although the above-mentioned conventional static pressure pad has a sufficient thin plate holding function, further improvements are desired depending on the application for which it is used. For example, in the vertical heat treatment furnace for steel strip shown in FIG. 3, when a conventional static pressure pad 11 having symmetrical slits shown in FIG. The gas is transferred to the cooling zone 14 or the heating zone 13 as shown by the arrow.
and influences the atmospheric temperature of each furnace zone. Particularly in a heat treatment line for high-quality strips, temperature changes in each zone (particularly in the heating zone), even if minute, are not desirable.

An object of the present invention is to provide a static pressure pad that can control the amount and direction of gas flowing along a thin plate in order to suppress the inflow of discharged fluid that adversely affects the quality of the thin plate. shall be.

[0007]

[Means for Solving the Problems] To achieve this object, the static pressure pad of the present invention is arranged symmetrically across the running line of the thin plate or close to the running line, and has the running line on the surface facing the thin plate. In a static pressure pad having a fluid ejection slit in a direction perpendicular to the direction at least near the entrance/exit side of the thin plate, one of the slits along the running line of the thin plate is inclined inward of the pad at an angle θ1. At the same time, the angle θ2 of the slit on the opposite side with respect to the thin plate surface is at least substantially perpendicular or inclined outward. In the present invention, the above-mentioned slit inclination angle θ1 is 60° to 30°, θ2
is preferably in the range of 90° to 140°.

[0008]

[Embodiment] The following description will be made based on the embodiment shown in the drawings. FIG. 1 shows an example of a static pressure pad according to the present invention, in which a pair of static pressure pads 2 are arranged symmetrically with a strip 1 in between, and gas (for example,
Inert gas, air, etc.) is blown at a predetermined pressure, and this gas is ejected from a slit 6 formed near the end of the strip inlet/output side of the plate portion 5 facing the strip 1 to maintain the strip 1 in a non-contact state. do. The structure, fluid supply section, etc. of the static pressure pad itself are all known.

The illustrated slit 6 is located perpendicular to the sheet passing line, but the plate portion 5 of the static pressure pad has not only the slit but also a slit in a direction parallel to or crossing the sheet passing line. There are also slits, and each slit is independent or continuous in a loop.

In the present invention, however, the exhaust gas flow is controlled by appropriately selecting the ejection angle of the slit 6 located perpendicular to the plate passing line in the above-mentioned static pressure pad. That is, among the slits perpendicular to the threading line, one slit 6a (bottom side in the figure) along the running line of the strip 1 is formed so as to be inclined at an angle θ1 toward the inside of the pad, and The angle θ2 of the slit 6b on the opposite side is formed to be at least approximately a right angle (in the example shown) or to be inclined outward from the pad.

In the example shown in FIG. 1, a vertical annealing equipment is shown in which a heating zone 7 is disposed below a pad 2 and a cooling zone 8 is disposed above it. In other words, the case where a large amount of water flows toward the downstream side of the strip (cooling zone side) is taken as an example. This is to prevent a large amount of low-temperature gas exhaust flow from flowing into the high-temperature heating zone 7, lowering the internal temperature of the heating zone and causing problems in the heating process. As shown in the figure, by tilting the slit 6a upward at an angle θ1 and making the angle θ2 of the slit 6b almost perpendicular to the strip, most of the gas ejected from the slit 6a flows in the advancing direction of the strip 1.
The ejected gas from the other slit 6b is also involved to make the upper exhaust gas flow Q1 larger than the lower exhaust gas flow Q2. Of course, some of the gas from the slit 6a flows downstream along the strip 1, but the amount can be very small so as not to affect the heating zone. By changing the two angles θ1 and θ2 and their combination, the gas flow rates Q1 and Q2 can be adjusted, or by reversing the positions of the angles θ1 and θ2, the gas discharge amount can be increased on the Q2 side. You can also.

[0012] Note that the two slit angles θ1 mentioned above
, θ2 are as follows. First, regarding the slit angle θ1, 60° to 30°
It is preferable that That is, if the angle is less than 30°, the slit will be too acute, and most of the gas ejected from the slit will flow parallel to the strip surface, which may reduce the strip retention function, which is the original purpose of the static pressure pad. . Furthermore, if the angle exceeds 60°, the direction of the gas that collides with the strip surface and flows is not constant, making it difficult to control the direction of the flow of exhaust gas flowing on the strip surface. cannot be achieved. Therefore, the slit angle θ1 is maintained within the range of 60° to 30°.

[0013] Regarding the slit angle θ2, 9
It is desirable to set it as the range of 0 degrees - 140 degrees. this is,
If it is less than 90 degrees, it will give unnecessary resistance to the controlled gas flow ejected from the slit 6a, making it impossible to obtain the gas flow in the desired direction and flow rate, and if it exceeds 140 degrees, This is because there is an inconvenience that the holding function of the strip is deteriorated and the gas flow from the slit 6a is accelerated more than necessary.

In actual operation, the above slit angle θ1 is influenced by conditions such as the amount of gas supplied to the pad, the distance between the pad surface and the strip surface, and the slit width.
, θ2, the gas exhaust flow Q
1 and Q2 can be adjusted over a certain range. Of course, these angles θ are determined experimentally in advance.
It is necessary to find the relationship between 1 and θ2 and the gas discharge flow rates Q1 and Q2.

[0015] In the illustrated example, the static pressure pad provided between the heating zone and the cooling zone of a vertical annealing furnace has been explained as an example, but the present invention is not limited to this embodiment. It goes without saying that this method can also be applied to equipment and lines where some kind of effect can be expected by controlling the amount. Further, the present invention is not limited to pads arranged symmetrically across the running line of the thin plate, but can also be applied to pads arranged alternately in a staggered manner across the line, or pads arranged only on one side.

Furthermore, when changing the slit angle, for example, the pad body itself may be changed to one having slits at a different angle, or the face plate portion of the pad in which the slits are formed may be constructed to be replaceable. All you have to do is replace it with the one you prepared at a different angle.

[0017]

Effects of the Invention According to the static pressure pad of the present invention as described above, the discharge flow of the gas ejected from the slit can be arbitrarily controlled. It has become possible to significantly reduce the negative effects caused by fluid intrusion. Therefore, if the present invention is applied to a thin plate threading/heat treatment line, the industrial effect will be very large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a static pressure pad according to the present invention.

FIG. 2 is a sectional view showing a typical example of a conventional static pressure pad.

FIG. 3 is a schematic diagram showing an example of using a static pressure pad in vertical annealing equipment.

[Explanation of symbols]

1 Strip 2 Static pressure pad 3 Pad body 4 Gas supply section 5 Plate part 6 Slit 7 Heating zone 8 Cooling zone

Claims (2)

[Claims] 1. A static pressure pad which is disposed symmetrically across or close to the running line of the thin plate and has a fluid ejection slit in a direction perpendicular to the running line on the surface facing the thin plate, at least near the entrance/exit side of the thin plate. Among the slits, one of the slits along the running line of the thin plate is formed to be inclined toward the inside of the pad at an angle θ1, and the slit on the other side is formed at an angle θ2 with respect to the thin plate surface.
A static pressure pad for gas flow control, characterized in that the pad is formed so as to be at least approximately perpendicular or inclined outwardly. Claim 2: The slit inclination angle θ1 is 60° to 3
Claim 1: 0° and θ2 are in the range of 90° to 140°.
Hydrostatic pad as described.