JPH06182425A - Cooling device for high temperature steel material - Google Patents

Abstract

(57) [Abstract] [Purpose] To maintain the slit nozzle outlet spacing with high accuracy and uniformity, and to make the flow distribution in the nozzle longitudinal direction uniform. [Structure] A water supply header 11 connected to a water supply pipe is connected to a water supply pipe 12 at a predetermined interval in the longitudinal direction. A nozzle header 13 including a rectifying chamber B having a rectifying plate 15 inside is detachably attached to the water supply pipe 12. A nozzle support plate 18 is detachably attached to the nozzle header 13 on the side opposite to the straightening chamber via a nozzle spacer 16. A pair of nozzle plates 19a and 19b attached to the nozzle header 13 and the nozzle support plate 18 form a predetermined slit nozzle. The ventilation pipe 20 is connected to the top of the nozzle header 13 with a predetermined space. An on-off valve 21 is provided in the middle of the ventilation pipe 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for uniformly and highly accurately controlling and cooling a high temperature steel material such as a steel sheet to a predetermined temperature.

[0002]

2. Description of the Related Art Generally, when a wide high temperature steel material is cooled with a refrigerant, a slit nozzle is used as a refrigerant discharge nozzle to generate a laminar flow, which has a higher cooling capacity than a pipe nozzle. In addition, since it is well known that the cooling uniformity in the width direction of the material to be cooled is also excellent, in recent years, for example, in the hot rolling hot run table as well, the cooling method using the slit laminar has been widely used.

However, recently, even more delicate control is required for cooling high temperature steel materials, and even when a slit nozzle is used, there are various ways to ensure uniform cooling capacity. Problems have been pointed out.

For example, when heat-treating a steel sheet online, the water pressure load in the nozzle, thermal strain due to radiant heat received from the hot steel sheet, vibration generated when the steel sheet is conveyed, and bending deformation due to its own weight, etc. Often, the slit nozzle is gradually deformed under the influence of various operating environment conditions, and the slit gap often largely deviates from the initial set value. For this reason, not only the uniform cooling performance, which is the greatest feature of using a slit nozzle due to uneven flow distribution in the plate width direction and water film breakage, but also the laminar flow is disturbed and the cooling capacity deteriorates. There was a problem of doing.

[0005] Therefore, there has been a case where a means such as attaching a space adjusting bolt at the slit outlet of the slit nozzle and adjusting the space during maintenance has been adopted. However, in order to prevent deformation as much as possible, the members that make up the nozzles are often highly rigid, so once deformation occurs, it is extremely difficult to restore a uniform slit outlet spacing with the spacing adjustment bolt. It was very difficult.

Further, in the header closed type slit laminar nozzle as shown in FIGS. 8 and 9, since the internal pressure of the nozzle header 1 portion can be made a negative pressure, a laminar flow having a high rectification degree can be obtained. Since water is supplied to the header 1 from one end or both ends of the nozzle header 1, the pressure on the water supply side in the nozzle header 1 decreases and a pressure gradient is generated, resulting in a uniform flow rate distribution in the plate width direction. There was a problem that I could not do it. 8 and 9
In FIG. 2, 2 is a straightening pipe inserted in the nozzle header 1, 3 is also a straightening plate, 4 is a straightening pipe supplied from the straightening pipe 2 into the nozzle header 1, and the cooling water flowing out through the straightening plate 3 is a cooled material. The nozzle side plates 5 that guide the nozzle side plates 5 are cylinders that adjust the slit spacing at the outlet of the nozzle side plate 4.

Therefore, in order to solve the above problems,
It has been proposed that one of the slit nozzle side plates be configured to be movable to prevent maintainability and variations in slit intervals, or to prevent thermal deformation by cooling the nozzle side with water.

[0008] For example, in Japanese Utility Model Publication No. 62-39846, the nozzle spacing is provided at a connecting portion between a stationary nozzle plate whose upper end is fixed to a header and a movable nozzle plate which opposes this and whose upper end is movably supported. With a slit nozzle with a structure in which a packing with a thickness corresponding to
A cooling device has been proposed which attempts to improve maintainability.

Further, in Japanese Utility Model Laid-Open No. 58-4210, a plate-shaped nozzle portion, which is constructed independently of the header tube, is mounted by being supported by a flange or the like, and the plate-shaped nozzle portion has a box structure capable of being water cooled. In addition to the above, a cooling device has been proposed which attempts to improve the maintainability by allowing the box portion to have rigidity against changes with time due to external force, thermal strain, and the like.

Further, in Japanese Utility Model Publication No. 59-35293, there is provided a water supply hole having a large number of water outlet holes opened at substantially equal intervals in a header outer pipe having a nozzle portion, and an end portion opposite to a water supply end is closed. By providing a pipe and a conduit for guiding a part of the cooling water on the water supply end side to the closed end side in the water supply pipe, even when water is supplied to one side, it is possible to obtain a uniform flow rate distribution in the nozzle longitudinal direction. A cooling device has been proposed.

[0011]

As described above, one side of the nozzle side wall is movably supported (No. 62-39846), or the nozzle side plate has a water-cooled box structure (no actual opening). Sho 58-4210
No.) or by making the water supply pipe to be inserted into the outer pipe of the header a double pipe structure.
No.), the maintainability and the uniform cooling property have been further improved, but in reality, there are still the following problems.

That is, when the nozzle side plate is composed of a movable side and a fixed side as in Japanese Utility Model Publication No. 62-39846,
When the stationary side nozzle plate is deformed, it is necessary to repair the entire nozzle, which increases the maintenance cost.

Also, as in Japanese Utility Model Laid-Open No. 58-4210,
When the nozzle side plate has a box structure that can be water-cooled, deformation due to thermal strain of the nozzle side plate itself can be almost eliminated, but there is no mechanism to maintain the nozzle gap, especially when applied to the controlled cooling of wide material of thick steel plate. It is still difficult to maintain the outlet interval of the slit nozzle having a width of 5 m with high accuracy throughout.

When the water supply pipe is a double pipe and the flow distribution is made uniform as in Japanese Utility Model Publication No. 59-35293, the header pressure at both ends is lower than that in the central part, so The distribution cannot be made sufficiently uniform.

The present invention eliminates the above-mentioned problems in the conventional cooling device, and can maintain the slit nozzle outlet spacing with high accuracy and uniformity even when affected by thermal strain, external force, etc., and is excellent in maintainability. An object of the present invention is to provide a cooling device for high-temperature steel material, which can accurately uniformize the flow rate distribution in the nozzle longitudinal direction and realize uniform cooling in the width direction of the material to be cooled.

[0016]

In order to achieve the above-mentioned object, a cooling device for high temperature steel according to the present invention comprises a water supply pipe which is connected to a water supply pipe and which is connected to a water supply pipe at a predetermined interval in the longitudinal direction. A header, a nozzle header removably attached to the water pipe, and a rectifying chamber having a rectifying plate inside, and a nozzle spacer on the side opposite to the rectifying chamber of the nozzle header detachably attached via a nozzle spacer. And
When attached, a nozzle support plate that forms a predetermined slit nozzle by a pair of nozzle plates attached to each is connected to the top of the nozzle header at a predetermined interval, and an opening / closing valve is provided in the middle thereof. It is equipped with a vent pipe.

[0017]

In the cooling device for high temperature steel of the present invention, the flow straightening chamber is provided on the side of the nozzle header to reduce the amount of refrigerant at the inlet of the slit nozzle as much as possible, and an opening / closing valve is provided in the middle thereof. Since the trachea is connected to the top of the nozzle header with a predetermined interval, the responsiveness becomes particularly good when OFF. Further, according to the present invention, since the gap between the slit nozzle outlets is adjusted by the nozzle spacer, the gap between the slit nozzle outlets can be kept uniform and highly accurate in the nozzle longitudinal direction.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in FIGS. FIG. 1 is a vertical cross-sectional view showing one embodiment of a cooling device for high-temperature steel according to the present invention, and FIG.
FIG. 3A is a partial cross-sectional view, FIG. 3 is a view showing an embodiment of the shape of a nozzle spacer, and FIG. 4 is an explanatory view of a uniform cooling method by the device of the present invention.

In FIGS. 1 and 2, reference numeral 11 denotes a water supply header whose one end or both ends is connected to a water supply pipe (not shown), and the water supply pipe 12 has a predetermined interval in the longitudinal direction of the water supply header 11. It is connected. The water pipe 12 is detachably attached to one side of the nozzle header 13 with, for example, bolts 14a and nuts 14b.
The tip of the water supply pipe 12 is located in a pressure equalizing chamber A provided in the nozzle header 13.

Therefore, the refrigerant sent from the water supply pipe passes through the water supply header 11 and the water supply pipe 12, and from the straightening hole 12a formed at the tip of the water supply pipe 12 to the nozzle header 13
It flows into the pressure equalizing chamber A inside. At this time, in the water supply header 11, the pressure on the water supply port side becomes low and a pressure gradient occurs in the longitudinal direction, but the refrigerant further passes through the water supply pipe 12 and the pressure equalizing chamber A
It flows in at right angles to the direction of the pressure gradient, and the refrigerant flows are mixed in the pressure equalizing chamber A to sufficiently equalize the pressure in the longitudinal direction, so even if water is supplied from one end or both ends, it is uniform in the longitudinal direction of the nozzle. It is possible to obtain a wide flow rate distribution.

The flow of the pressure-equalized refrigerant in the pressure equalizing chamber A is
It flows into the rectification chamber B as a uniformly rectified flow from many pores 15a of the rectification plate 15 provided between the pressure equalization chamber A and the rectification chamber B provided above it. The flow of the refrigerant rectified in the rectification chamber B through the large number of pores 15a is formed on the side opposite to the rectification chamber B of the nozzle header 13 through the top C in the nozzle header 13 following the rectification chamber B. It flows into the slit nozzle.

By the way, the slit nozzles are attached to the nozzle header 13 through the nozzle spacers 16, for example, a nozzle support plate 18 which is detachably attached by, for example, bolts 17a and nuts 17b, and the opposing surfaces of the nozzle header 13. A pair of nozzle plates 19a
-Formed by 19b, the exit distance T of the slit nozzle
The value of o can be maintained uniformly with high precision in the longitudinal direction of the slit nozzle. That is, the nozzle support plate 18 and the nozzle header 13 are sandwiched from both sides of the nozzle spacer 16, and the fixing bolt 17c and the nut 17 are fixed from both sides.
By tightening at d, the nozzle support plate 18 and the nozzle plates 19a and 19b can be prevented from being deformed, and the outlet distance To of the slit nozzle can be always kept constant.

Here, in order to sufficiently rectify the flow of the refrigerant in the slit nozzle, the pressure Ps at the top C of the nozzle header 13 having the relationship represented by the following formula 1 is a negative pressure (below atmospheric pressure). On the other hand, the shorter the slit nozzle length L (see Fig. 1) is ON / OF.
Since the F response is good, the slit nozzle length L is set to P in order to sufficiently rectify the laminar flow to prevent film breakage and flapping and to obtain the maximum cooling capacity.
It is necessary to determine so that s <0.

[0024]

[Number 1] ^{Ps = (0.5ρVo 2 -ρgL) ×} 10 [mmAq] However, Vo; outlet flow rate of the slit nozzle [m / sec] [rho; refrigerant density [kg / m ^3] g; gravitational acceleration (9. 8m / s ² )

However, the outlet flow velocity Vo of the slit nozzle
Is about 1 to 1.5 m under normal insertion conditions,
From the above formula 1, it can be seen that L> Vo ² / 2g = 120 [mm] is sufficient.

In order to control the cooling end target temperature of the material to be cooled with high precision, the discharge from the slit nozzle outlet of the laminar flow is completely completed from the moment when the supply of the refrigerant into the water supply header 11 is started or stopped. It is necessary to shorten the time required for starting or stopping (ON · 0FF response time) as much as possible, but for that purpose, it is necessary to reduce the amount of the refrigerant accumulated above the entrance of the slit nozzle as much as possible. Therefore, in the present invention, the rectifying chamber B is separately provided on the side of the top portion C of the nozzle header 13 to sufficiently reduce the volume of the top portion C.

In addition, in the present invention, the nozzle header 13
By providing an opening / closing valve 21 in the middle of a ventilation pipe 20 connected to the top portion C of the ventilator at a predetermined interval in the longitudinal direction, and closing the valve when it is ON and opening it when it is OFF to communicate with the atmosphere, The response time when turned off is further shortened.

In the present invention, the shape of the nozzle spacer 16 is not particularly limited, but in order to reduce the resistance received from the refrigerant flow in the slit nozzle and to minimize the turbulence caused by the insertion of the nozzle spacer 16. In addition, it is desirable to have a shape close to a streamline shape as in the embodiment shown in FIGS. 3 (a) to 3 (c). Also,
In order to re-rectify the turbulence generated by inserting the nozzle spacer 16, as shown in FIG. 1, a tapered portion D is formed in the middle of the slit nozzle, and the refrigerant is narrowed from the inlet interval Ti to the outlet interval To. It is necessary to narrow down the flow.
Although this draw ratio r (= Ti / To) varies depending on the use conditions, it is usually desirable to set it to about 2 to 5 times. In addition,
In the present embodiment, a parallel portion, which is about 10 to 50 times the outlet interval To, is provided downstream of the tapered portion D so that the laminar flow immediately after the discharge is not disturbed.

In actual operation, several to several tens of nozzle headers 13 may be installed in parallel. In such a case, as shown in FIG. 4 (a), the nozzle flow F is the material to be cooled. P
An interference flow Fo generated by the collision above is generated, but this interference flow Fo is extremely unstable and constantly vibrates between nozzles. Therefore, a part of the interference flow Fo may collide with the cooled material P of the nozzle flow F in some cases. You may get caught in it. In such a case, since the cooling capacity in the vicinity of the collision point becomes extremely high, large cooling unevenness occurs.

Therefore, as shown in FIG. 4 (b), the gap between the nozzle headers 13 is made sufficiently small so that the nozzle headers 13 are filled with the interference flow Fo, whereby the cooling unevenness can be prevented. In this case, the conventional nozzle header requires a mechanism for adjusting the nozzle outlet spacing, or has a structure that provides rigidity to the nozzle side wall to prevent the occurrence of thermal strain, etc. It could not be made sufficiently small and the uneven cooling due to the interference flow Fo could not be prevented. However, in the present invention, as described above, since the nozzle outlet intervals are made uniform by the nozzle spacers 16, the overall structure of the nozzle header 13 can be made significantly smaller than in the conventional case, and therefore the interference flow Fo causes Nozzle header 1 until there is no uniformity
The distance between the three can be reduced.

In the present invention, the shorter the distance between the water supply pipes 12 is, the more the pressure equalizing effect is increased. However, considering the manufacturing cost, the longer the distance is, the better. According to the results of experiments conducted by the present inventor, it was found that if the thickness is 300 mm or less, practically necessary uniformity can be obtained.

Next, the results of experiments conducted to confirm the effects of the present invention will be described. FIG. 5 shows the cooling device of the present invention having the configuration shown in FIGS. 1 and 2 and the conventional cooling device (slit nozzle outlet interval To = 7 mm), in which cooling water is discharged from the slit nozzle outlet after the water supply to the nozzle header is stopped. It is drawing which shows the result of having investigated the time required until it stopped completely. As is clear from FIG. 5, in the device of the present invention, the responsiveness at the time of OFF is also greatly improved as compared with the conventional device, so that the steel plate temperature can be controlled with high accuracy.

FIG. 6 is a diagram showing the results of measuring the flow rate distribution in the plate width direction using the same device as in FIG. As is apparent from FIG. 6, in the case of the conventional device, in addition to the flow distribution unevenness that the central part becomes high because cooling water is originally supplied from both ends, it is caused by thermal strain during use. Although local unevenness occurs due to deformation, it can be seen that the apparatus of the present invention provides a substantially completely uniform distribution over the entire width direction of the plate, and is excellent in uniform cooling ability and maintainability.

FIG. 7 shows a cooling system in which the same device as that shown in FIG. 5 is arranged at a high density as shown in FIG. 3 (b) to eliminate the influence of interference flow and is used in a control cooling line for thick steel plates. It is an example of the measurement result in the plate width direction at the end. As is apparent from FIG. 7, compared with the case where the conventional apparatus is used, the flow rate distribution is uniform when the apparatus of the present invention is used, and
Since non-uniform cooling does not occur due to the vibration phenomenon of the interference flow,
It was found that the uniformity of temperature distribution in the strip width direction was significantly improved.

[0035]

As described above, according to the present invention,
A material to be cooled such as a high-temperature steel plate can be uniformly cooled in the width direction, and further, ON / OFF response is excellent, and highly accurate temperature control of the material to be cooled becomes possible. Further, since the nozzle header is more compact than the conventional one, it is possible to arrange the nozzle header with a short interval so as to eliminate uneven cooling due to the interference flow on the material to be cooled. Furthermore, even when used in actual operation for a long period of time, the outlet interval of the slit nozzle does not change,
Excellent maintainability.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing one embodiment of a cooling device for high temperature steel according to the present invention.

FIG. 2 is a partial cross-sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing an example of the shape of a nozzle spacer.

FIG. 4 is an explanatory diagram of a uniform cooling method by the device of the present invention.

FIG. 5 is a diagram comparing response times when the cooling device of the present invention and a conventional cooling device are OFF.

FIG. 6 is a diagram comparing measurement results of flow rate distributions of the cooling device of the present invention and the conventional cooling device.

FIG. 7 is a diagram comparing the temperature distributions of the cooling device of the present invention and the conventional cooling device at the end of cooling.

FIG. 8 is a front view showing an example of a conventional cooling device.

9 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 11 water supply header 12 water supply pipe 13 nozzle header 15 straightening plate 16 nozzle spacer 18 nozzle support plate 19a nozzle plate 19b nozzle plate 20 ventilation pipe 21 opening / closing valve B straightening chamber

Claims (1)

[Claims] 1. A water supply header connected to a water supply pipe and connected to the water supply pipe at a predetermined interval in the longitudinal direction, and a rectifier detachably attached to the water supply pipe and having a rectifying plate inside. A nozzle header having a chamber and a nozzle spacer that is detachably attached to the side of the nozzle header opposite to the straightening chamber via a nozzle spacer, and when attached, a predetermined slit nozzle is formed by a pair of nozzle plates attached to each. A cooling device for high-temperature steel material, comprising: a nozzle support plate to be formed; and a vent pipe connected to the top of the nozzle header at a predetermined interval and having an opening / closing valve in the middle thereof.