JPH0437887Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a suction type cooling roll used in steel making lines and the like.

<Prior Art> A suction type cooling roll is known as one of the cooling means used in continuous annealing equipment for metal plates, heat treatment lines, etc.

The structure and operation of the conventional suction cooling roll will be explained with reference to FIG. 5, which shows a vertical cross section of a conventional suction type cooling roll, and FIG. 6, which shows a cross section taken along line C--C in FIG.

In the figure, a relatively thin-walled outer cylinder 1a and a relatively thick-walled inner cylinder 1b constituting the roll body 1 are diffusion welded, and an axial groove is formed on the entire circumference of the inner surface of the outer cylinder 1a. A large number of refrigerant holes 2 are formed on the outer surface of the inner cylinder 1b. Hollow ring-shaped boxes 5, 6 are provided on the outer surfaces of the mirror plates 3, 4 at the left and right ends of the roll cylinder 1.
A large number of pipes 7 and 8 communicating with the refrigerant hole 2 via the refrigerant holes 2 are installed radially. Left and right mirror plates 3, 4
The roll shafts 9, 10 joined to the hollow portions 11, 10,
12, and a bearing 1 fitted in the body.
3 and 14 for free rotation. The left roll shaft 9 has a double hollow structure having a hollow part 15 at its base outside the hollow part 11 communicating with the pipe 7, and the outer hollow part 15 is on the right side of the bearing 13. It communicates with a refrigerant supply rotary joint 16 fitted into the body of the roll shaft 9 . The hollow portion 12 of the roll shaft 10 on the right side communicates with the piping 8, and further communicates with a refrigerant discharge rotary joint 17 fitted to the body of the roll shaft 10 on the right side of the bearing 14.

On the other hand, the inner cylinder 1 is connected to the roll cylinder 1 from the outer surface of the outer cylinder 1a.
Small diameter suction hole 18 that penetrates to the inner surface of b
However, about 10,000 holes are made, avoiding the refrigerant holes 2. A suction rotary joint 19 is fitted into the body of the left roll shaft 9 on the left side of the bearing 13, and communicates with the hollow portion of the roll shaft 9. In the center of the left mirror plate 3, there is a left roll shaft 9.
A hole having the same diameter as the hollow part is made, and the hollow part 20 of the roll cylinder 1 communicates with the hollow part 11 of the roll shaft 9.

The procedure for cooling a hot steel strip using this suction type cooling roll will be explained.

First, wrap the heated steel strip around the roll cylinder at an appropriate angle.
Arrange the equipment so that it wraps around the Next, a vacuum pump (not shown) is driven to evacuate the hollow portion 20 of the roll barrel 1 via the suction rotary joint 19 and the roll shaft 9. At the same time, a low-temperature refrigerant is sent from the refrigerant supply rotary joint 16 to the refrigerant hole 2 via the pipe 7 to cool the roll cylinder 1 . After cooling the roll body 1, the refrigerant is discharged from the discharge rotary joint 17 via the pipe 8 and the hollow part 12 of the roll shaft 10.

In this state, when the heated steel strip is wound around the roll cylinder 1 and fed, the roll cylinder 1 rotates freely by the bearings 13 and 14 fitted to the roll shafts 9 and 10, so the roll cylinder 1 is heated. Rotates according to the feed of the steel strip. At this time, since the hollow part 20 of the roll body 1 is evacuated, the gas existing between the roll body 1 and the hot steel strip is sucked through the suction hole 18, and the hot steel strip is brought into close contact with the roll body 1. . Therefore, the heat exchange efficiency between the hot steel strip and the roll cylinder 1 is increased, and uneven cooling of the hot steel strip due to lifting of the hot steel strip on the roll cylinder 1 is eliminated.

<Problems to be solved by the invention> By the way, the diameter of the suction hole 18 is as small as about 1 mm so as not to damage the metal plate to be cooled, and the wall thickness of the roll cylinder 1 is about 60 mm from the viewpoint of strength. Due to their large size, combined with the large number of suction holes, it is difficult to drill the suction holes 18 by cutting, and special methods such as electric discharge machining or laser machining are required to be performed, which are disadvantageous in terms of processing cost and processing time. . Even with this special processing method, it is not easy to penetrate the suction hole 18 from only one side of the roll cylinder 1, and a method is used in which half of the suction hole 18 is processed from the outer side and half of the inner side to make communication. but,
High positional accuracy is required to align the holes machined from both sides at the center of the wall thickness of the roll cylinder 1, and it is also impossible to weld the outer cylinder 1a and the inner cylinder 1b after drilling the holes.

As described above, in the conventional technology, the time and cost required for machining the suction hole 18 are enormous.

On the other hand, the following equation is known to determine the suction performance for adsorbing the hot steel strip onto the roll cylinder 1.

P ₁ = P ₂ + λ・l/d・γV ² /2g ...(1) Here, P ₁ : Gap pressure between hot steel strip and roll body P ₂ : Pressure inside roll body λ : Pressure in suction hole passage Loss coefficient l: Length of suction hole (thickness of roll body) d: Diameter of suction hole γ: Density of gas v: Flow velocity of gas g: Acceleration of gravity.

In order to increase the cooling efficiency of the hot steel strip,
It is necessary to make P ₁ small so that the hot steel strip comes into close contact with the roll cylinder 1, but here too, d (the diameter of the suction hole 1) is small and l (the thickness of the roll cylinder) is large, so a good result is obtained. Suction performance was becoming difficult to obtain.

<Means for solving the problem> Therefore, in the present invention, a refrigerant passage is formed in the roll body constituted by an outer cylinder and an inner cylinder inscribed in the outer cylinder, and the refrigerant is passed through the refrigerant passage. So,
In addition, in a suction type cooling roll in which a small-diameter suction hole is provided that communicates from the outer surface of the outer cylinder of the roll cylinder to the inner surface of the inner cylinder, and outside air is sucked into the inside of the roll cylinder from the surface of the roll cylinder, The hole diameter in the inner part was made larger than the hole diameter in the outer part of the roll body.

<Function> Since the hole diameter of the inner part of the suction hole is larger than the hole diameter of the outer part, machining of the inner cylinder side hole diameter is easy, and even if the positional accuracy of drilling is low, the holes can communicate with each other. Become. Furthermore, the suction performance is improved because the flow resistance of gas passing through the suction holes is reduced.

<Example> An example of the present invention will be described using FIGS. 1 to 4.

Fig. 1 shows a longitudinal section of the first embodiment of the suction type cooling roll of the present invention, Fig. 2 shows details of the A-A cross section in Fig. 1, and Fig. 3 shows The details of section B in FIG. 1 are shown. still,
The structure of this embodiment is the same as that of the conventional apparatus described above (FIG. 5) except for the suction holes formed in the roll cylinder, so the same parts are given the same reference numerals and redundant explanation of the structure will be omitted.

As shown in FIGS. 2 and 3, the suction hole 18 in this embodiment has a small diameter portion 18a on the first outer surface of the roll cylinder, that is, on the outer cylinder 1a side, similar to the conventional device.
The inner surface, that is, the inner cylinder 1b side is the large diameter portion 18b. The procedure for machining the suction hole 18 in this embodiment is as follows: the outer cylinder 1a and the inner cylinder 1.
After welding b, the small diameter portion 18a is machined from the outer cylinder 1a side using the same method as in the conventional apparatus, and the large diameter portion 18b is machined from the inner cylinder 1b side by normal cutting.

Fig. 4 shows a second embodiment in which the roll cylinder 1 is manufactured by drilling holes in the outer cylinder 1a and the inner cylinder 1b and welding them together, and shows the details of group B in Fig. 1. ing.

<Effects of the invention> By making the suction holes in the roll cylinder smaller in diameter on the outside of the roll cylinder and larger on the inside of the roll cylinder, A. The amount of special machining required to make small diameter holes is reduced. processing cost and processing time are both reduced.
In addition, compared to the conventional method in which small diameter holes are machined separately from the outer cylinder side and the inner cylinder side of the roll cylinder and communicated with each other,
Since there is a difference in the diameter of the hole drilled from the outer cylinder side and the inner cylinder side, communication is possible even if the positional accuracy is low. It became possible to weld the tube,
Furthermore, C l (length of suction hole) in equation (1) above
Since the small diameter portion of the roll body becomes short and the remaining part of the roll body has a large diameter, _P1 becomes smaller and suction efficiency improves.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention;
Fig. 2 is a detailed view of the section A-A in Fig. 1, Fig. 3 is a detailed view of section B in Fig. 1, and Fig. 4 is a detailed view of section B in Fig. 1, showing the second embodiment. , FIG. 5 is a vertical cross-sectional view showing a conventional example, and FIG. 6 is a detailed cross-sectional view taken along line CC in FIG. In the drawing, 1 is a roll cylinder, 1a is an outer cylinder, 1b is an inner cylinder, 2 is a refrigerant hole, 3 and 4 are end plates, 5 and 6 are boxes, 7 and 8 are piping, 9 and 10 are roll shafts, 11,
12 is a hollow part (inside the roll shaft), 13 and 14 are bearings,
15 is a hollow part (inside and outside of the roll shaft), 16 is a rotary joint for refrigerant supply, 17 is a rotary joint for refrigerant discharge, 18 is a suction hole, 18a is a small diameter part (suction hole), and 18b is a large diameter part (suction hole). 19 is a rotary joint for suction, and 20 is a hollow hole (inside the roll cylinder).

Claims (1)

[Scope of utility model registration request] A refrigerant passage is formed in the roll cylinder constituted by an outer cylinder and an inner cylinder inscribed in the outer cylinder, and the refrigerant is passed through the refrigerant passage, and from the outer cylinder outer surface to the inner cylinder inner surface of the roll cylinder. In a suction type cooling roll in which a small-diameter suction hole is provided that communicates with the roll body to suck outside air into the inside of the roll body from the surface of the roll body, the diameter of the suction hole on the inner side of the roll body is equal to the diameter of the hole on the outside of the roll body. A suction type cooling roll characterized by being larger than the diameter.