JPS60245718A - Cooler for axisymmetrical object - Google Patents

Abstract

PURPOSE:To perform cooling uniform in circumferential and axial directions by constituting a cooler of a ring pipe having plural pieces of injection ports formed by incising diagonally and notching the pipe toward the down flow direction of the inside swirling flow and plural pieces of injection pipes connected thereto from the direction tangential therewith and provided with orifices in the mid- way. CONSTITUTION:The cooler 11 is constituted by connecting, for example, two hot water ejecting pipes 12, 12a connected to the ring pipe 15 made of a steel pipe in the tangential direction thereof to hot water pipes via the evaporating orifices 13, 13a. Plural pieces of the injection ports 16 are provided to the pipe 15 by incising diagonally and notching said pipe in the down flow direction of the inside swirling flow. For example, the incising angle alpha of the injection port 16 is set at 45 deg. and 8 pieces of the ports 6 are provided equidistantly (beta=45 deg.) on the inside circumferential surface of the pipe 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cooling device for an axially symmetrical object such as a pipe billet.

[Prior art]

Currently, various methods have been proposed for online cooling of axially symmetric objects such as pipe billets, which require uniform cooling in the circumferential and axial directions, and some have been put into practice. There are various problems with this.

As an example, a spray cooling method and a burst cooling method currently used in secondary cooling of pipe billet continuous casting equipment (hereinafter referred to as billet CC) will be described below.

In the spray cooling method, flat spray nozzles and full cone nozzles are used, and these have eight nozzles arranged concentrically toward the center (the diameter of the circle connecting the nozzle nozzles is approximately 400m-).

Since the spray pattern of a flat spray nozzle is in the form of a very narrow band, the pipe billet is not cooled uniformly in the direction in which it is pulled out (in the axial direction), and as a result, cracks and flaws are likely to occur. In addition, the nozzle is easily clogged, which is a cause of failure. - In principle, full cone nozzles do not cause uneven cooling, but due to their structure, clogging is likely to occur.
Therefore, there is a problem in that the cooling performance of the clogged nozzle deteriorates, resulting in uneven cooling.

On the other hand, the mist cooling method is superior to the spray cooling method in terms of uniform cooling, but a particularly large amount of high-pressure air is required in the secondary cooling zone of the CC to achieve uniform cooling. For this reason, large air compressors, air holders, etc. are required as the amount of air increases, and of course the equipment becomes large-scale due to the number of piping, which not only increases equipment costs, but also increases the amount of air. There are many disadvantages, such as high operating costs due to the large number of

Particularly recently, there has been an increase in the production of high-grade steel materials, such as high-carbon steel, which are prone to cracking and flaws due to uneven cooling.
There is a strong desire to establish a new uniform cooling method and an energy-saving, equipment-saving cooling technology for axially symmetrical objects that meets the demands of the times.

[Purpose of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems, and provides a shaft that can perform uniform cooling in the circumferential direction and the axial direction, and that can satisfy the requirements for energy saving and equipment saving. The purpose is to obtain a cooling device for symmetrical objects.

[Summary of the invention]

The inventor of the present invention first supplies high-temperature, high-pressure water with a temperature exceeding 100°C to a nozzle, and at the exit of the nozzle, self-evaporation (flushing) occurs due to the depressurization effect released from the self-pressure to atmospheric pressure, resulting in water vapor that expands and An application was filed for an invention relating to a method for cooling a high-temperature object using hot water, in which a high-pressure gas-liquid two-phase flow consisting of finely broken water droplets generated at that time is applied to the object to be cooled, and the invention was patented (Patent No. 1151494) , Special public school 5th year
7-27926).

The present invention relates to a cooling device that is particularly effective when implemented in such a cooling method, and includes a ring pipe having a plurality of injection ports cut diagonally from the inside toward the downstream direction of the swirling flow; The present invention provides a cooling device for an axially symmetrical object, which comprises a plurality of injection pipes connected tangentially to the ring pipe and having orifices provided therebetween.

[Embodiments of the invention]

FIG. 1 is a conceptual diagram for explaining the present invention in detail, and FIG. 2 is a plan view of an embodiment of the present invention. In the figure, 1 is a hot water tank having skin heating means (not shown), 2 is a water supply pipe that supplies water to the hot water tank 1 via a water supply valve 3, and 4 is a water supply pipe that supplies water to the hot water tank 1 via a steam control valve 5. 6 is a hot water pipe that supplies hot water from the hot water tank 1 to the cooling device 11 via a control valve 7, 8 is a pressure gauge, 9 is a liquid level gauge, and 10 is a temperature gauge. It is the liver.

As shown in FIG. 2, the cooling device 11 includes two hot water jetting pipes 12 connected tangentially to a ring pipe 15 made of steel pipes.
．． '12a is connected to the hot water pipe B via an evaporation orifice (flushing orifice) 13.13a.

In the cooling device configured in this way, high-temperature, high-pressure hot water (100 to 160°C m a
x 7 to 9G/ca) is the flushing orifice 1
At 3°131k, a portion of the high-temperature, high-pressure single-phase hot water self-evaporates, forming a high-speed two-phase flow of steam and minute water droplets that are finely crushed by physical expansion during evaporation, and flows through the ring pipe 15.
The liquid flows into the ring pipe 15 and becomes a swirling flow. This swirling flow is injected to the object to be cooled 20 from a large number of injection ports 16 provided inside the ring pipe 15, and cools the object to be cooled 20.
Next, the cooling liquid according to the present invention will be described in detail with reference to Example 11. First, the flushing orifices (hereinafter referred to as orifices) 13, 13a have a structure as shown in FIG. 3, and the constricted portion 14 has a flow path shape. When high-temperature, high-pressure water passes through the constriction section 14, a low-pressure region is generated to promote the generation and growth of bubble nuclei, and the bubbles are continuously supplied to the subsequent gas to break the liquid. let me,
This is to achieve stable flushing.

Next, the injection port 16 provided inside the ring pipe 15 will be explained. The high-speed gas-liquid two-phase flow generated in the orifices 13, 13a flows tangentially into the ring pipe 15 and becomes a swirling flow within the ring pipe 15.
It is necessary to create a shape that can be used in everyday life. In this embodiment, as shown in FIG. 4, a plane perpendicular to the ring tube 15,
In the downstream direction of the swirling flow, a surface having an acute angle with respect to the perpendicular surface is used to cut the cut that occurs when the ring pipe 15 cuts into the object 20 to be cooled from the inside direction.
The cutting angle α of the injection ports 16 is 45°, and eight injection ports are provided on the inner circumference of the ring pipe 15 at equal intervals ψ−45°).

The cutting angle α of the injection port 16 was set to 45° because it was assumed that the present cooling device 11 would be implemented on a billet (CC). That is, in the billet CC, the billet (object to be cooled) 20 is transported in a structure in which one roll is fixed and the other roll is moved, as shown in FIG. Even if there is a change, it can be accommodated, and by setting the cutting angle α to 45°, the gas-liquid two-phase flow injected from the injection port 16
The billets (objects to be cooled) 20 having diameters from the maximum diameter to the maximum diameter are all set so that they can be oriented in the tangential direction.

FIG. 6 is an actual measurement diagram of the water amount density distribution obtained by the cooling device 11 according to the present invention, and the experimental conditions were as follows.

(1) Hot water conditions Hot water pressure (in the hot water tank) 4.2 kgG/cd Hot water temperature (in the hot water tank) 151°C (2) Cooling device ring pipe inner diameter 21.5 mm Orifice inner diameter 2.5 mm Thickness 5 ．． Qmm Number of injection ports 8 Cutting angle of injection ports 45° Flow rate 3.54/m-no z z l e (3) Measurement position On the surface of a cylinder with an outer diameter of 200 mm (distance to the injection port)
100 mm) As is clear from the figure, it was confirmed that the gas-liquid two-phase flow was evenly distributed in the circumferential direction.

FIG. 7 is a water volume density distribution diagram when a gas-liquid two-phase flow is injected vertically onto a plane from one injection port 16 of the cooling device 11 under the same conditions as above. Note that the distance between the injection port 16 and the plane is 100 mm.

As is clear from the figure, the spray butterfly has a circular shape. Therefore, when the main jet nozzle 16 is provided on the circumference, it can be used not only in the circumferential direction of the object to be cooled but also in the axial direction (back and forth). It is also possible to have a certain range of secularism in the direction (direction).

Next, regarding nozzle clogging, a comparison will be made between a conventional nozzle and the cooling device according to the present invention.

Table 1 Table 1 compares the dimensions of the injection port of the flat spray nozzle, the full two/nozzle, and the device of the present invention.

In the device of the present invention, only two orifices 1 and 16a are provided in one ring pipe 15, so the orifice 13.
1! It can be seen that the diameter of the constricted portion 14 of L can be increased, and therefore clogging is less likely to occur.

Figure 8 is a diagram comparing the cooling performance of the cooling device according to the present invention and a conventional mist nozzle. This figure compares the performance when using a conventional mist nozzle with the results of an experiment conducted under the following conditions.

Hot water cooling of the present invention Mist cooling flow rate 8t/-Water 81/- Air 16ONt/1ml+ Pressure 4.2 to 9G/lri Water 3kgG/d
(Temperature: 151°C) Air: 4g/m Air/water specific volume ratio) Approximately 200. 20 When the injection angle becomes large, the collision force decreases in the case of direct cooling, and especially when the heat transfer surface temperature is high,
However, in the case of hot water cooling, self-evaporation occurs instantaneously, and the vapor-droplet volume ratio due to volume expansion is as large as approximately 200, so the steam quickly transports the VC droplets and increases the collision force. can be maintained strongly over a wide area. Therefore, high cooling performance can be obtained even on high-temperature heat transfer surfaces. Therefore, it can be seen that even a single injection port 16 can cover a wide range of cooling, and is superior to other nozzles in terms of uniformity of cooling.

Considering the case where the cooling device of the present invention is applied to a billet CC, as shown in FIG.
Since the diameter of the object to be cooled (20) is changed, a problem arises in that the distance between the injection port 16 and the surface of the billet 20 in the circumferential direction is significantly different. In hot water cooling,
Cooling is performed by high-speed gas-liquid two-phase flow with a high air-water ratio, so even if the water density changes slightly, the collision force is large, so there is little change in cooling capacity. For example, in Fig. 8, the water density at a point above the injection angle of 104° is about 1/2 of the water density directly below the injection port 16, but there is almost no difference in cooling capacity. . That is, by changing the diameter of the billet 20, the distance between the billet 20 and the injection port 16 changes,
Even if the water density loses uniformity in the circumferential direction, the cooling device of the present invention using hot water is effective for uniform cooling.

FIG. 9 is a longitudinal sectional view of another embodiment of the orifice 16 having a structure that prevents clogging and allows flow rate adjustment.

In this embodiment, the orifice 13 (inner diameter of the constriction part 14 is 8 m)
m) flow control valve 17 (diameter 10 mm, tip angle 60°)
is mounted so as to be movable in the axial direction, and the shaft is sealed with a sealing material 18. According to such an orifice 16, stable flushing can be maintained and the flow rate can be increased from 6 to 20.
It is possible to adjust t/- over a wide range, and it is also easy to handle when self-supplied, and clogging foreign matter can be easily and quickly removed.

FIG. 10 is a plan view showing an embodiment in which the cooling device according to the present invention is applied to uniformly cooling a larger axially symmetrical object. (In the embodiment shown in Fig. 11, the hot water injection pipes 12 are installed at six locations in the tangential direction of the ring pipe 14, and each orifice 1 is
3 and 12 injection ports 16 are provided at 30° intervals. In addition, in the embodiment shown in Figure bJ, hot water injection pipes 12 having orifices 16 are installed at four locations, and 16 injection ports 16 are provided at intervals of 22.5 degrees. This represents how many orifices 13 and injection ports 16 should be provided in order to obtain the same level of cooling performance depending on the size of the object.

Table 2 In the above explanation, the case where the cutting angle of the injection port 16 of the ring pipe 15 was set to 450 was explained.
Depending on the diameter of 0, the cutting angle may be set between 0 and 90° as shown in Figure 10 (&), or it can be set on the upstream side of the swirling flow as shown in Figure (b). Diagonal cutting at an angle (-1) The entire cutting angle α2 may be set in the range of 90° to 150°.

Although the embodiments of the present invention have been described above, the number of injection pipes and injection ports and the shape of the injection ports of the present invention are not limited to the above embodiments. Needless to say, it should be selected appropriately depending on the uniformity and the like.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, an axially symmetrical object can be uniformly cooled in the circumferential and axial directions, and the requirements for energy saving and equipment saving can be satisfied. It's big.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram for explaining the present invention in detail, Fig. 2 is a plan view of an embodiment of the invention, Fig. 6 is a cross-sectional view of an embodiment of the orifice, and Fig. 4 is an embodiment of the injection port. 5 is an explanatory diagram showing the billet cooling state according to the present invention, FIG. 6 is an actual measurement diagram of the water amount density distribution by the apparatus of the present invention, and FIG. A density distribution diagram when a gas-liquid two-phase flow is injected, FIG. 8 is a diagram comparing the cooling ability of the device of the present invention and a conventional mist nozzle, and FIG. 9 is a sectional view of another embodiment of the orifice. Figure 10(a). 11(b) is a plan view of another embodiment of the present invention with some parts omitted, and FIGS. 11(a) and 11(b) are explanatory views showing other embodiments of the injection port. 11... Cooling device, 12.12a... Hot water injection pipe,
13.13&... orifice, 14... strangulation, 15
...Ring pipe, 16...Injection port, 20...Object to be cooled. Agent Patent Attorney Sanro Kimura

Claims (1)

[Claims] A ring pipe having a plurality of injection ports cut out diagonally toward the downstream direction of the inner swirl flow, and a plurality of injection pipes connected tangentially to the ring pipe and having an orifice in the middle. A cooling device for axially symmetrical objects consisting of: