JPS6354475B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a powder supply device to a mold for a continuous casting machine, and more specifically, it is a device for supplying powder to a mold for a continuous casting machine. It is related to the device for inputting. [Prior Art] In continuous casting, in which molten steel is cast into a continuous billet or the like with a predetermined cross-sectional shape, the molten steel is poured into a mold from a ladle or the like through a nozzle. While passing through the mold, the molten steel gradually solidifies and is cast into a shape corresponding to the cross section of the mold, and a continuous billet is pulled out from the other end of the mold. At this time, powder is supplied to prevent oxidation of the molten steel and to lubricate the molten steel and the mold. The tip of a nozzle that pours molten steel from a ladle into a mold is plunged into the molten steel in the mold, and is separately controlled so that the molten steel surface is always at a substantially constant height. The dimension between the inner walls of the mold is the same as the cross-sectional dimension of the billet, and the upper end of the mold is open except for the protruding nozzle, and the molten steel surface is open to the atmosphere. Therefore, the above-mentioned powder is appropriately introduced through the opening and taken into the mold together with the molten steel which is solidified and drawn out. Various types of powder are generally used, and the powder may be supplied into the mold by scattering it to the extent that it thinly covers the surface of the molten steel. The powder prevents oxidation of the molten steel in the mold, keeps it warm, and captures floating inclusions, and also promotes sliding between the inner wall of the mold and the molten steel that is starting to solidify, and improves mold separation. Therefore, the cast molten steel can be solidified to a desired degree while passing through the mold, and can be drawn out smoothly. [Problems to be Solved by the Invention] As described above, powder is supplied to the molten steel surface in the mold for the purpose of preventing oxidation and lubricating the powder, but the amount thereof is approximately constant. However, it is often changed depending on, for example, the dimensions of the billet to be cast, the composition of the molten steel, the usage conditions of the mold, and other factors. By the way, it is preferable that the powder be supplied to the molten steel surface as evenly as possible, and the amount needs to be adjusted appropriately, so it is not easy to mechanize it, and conventionally it has been done by relying on manual labor or relying on intuition. Adjustments have been made. Powder is poured onto the molten steel surface by scattering it through the opening at the top of the mold, but this work requires skilled workers to select the appropriate timing and amount of supply as well as ensure uniform distribution. It disappears. Moreover, the working environment is in a high temperature atmosphere, and workers are forced to perform harsh labor. The present invention was made to solve the above-mentioned problems, and its purpose is to be able to supply a predetermined amount of powder evenly distributed to the molten steel surface in the mold, and to easily change the amount of powder supplied. Provides a powder supply device for a mold for a continuous casting machine that can obtain the desired oxidation prevention and lubrication, eliminate the manual labor and skill required by the operator, and relieve the operator of harsh work. It is to be. [Means for Solving the Problems] The features of the powder supply device to a mold for a continuous casting machine of the present invention will be explained with reference to FIGS. 1 and 2. The powder 6 that has been conveyed in a fixed amount is transferred to the vertical tube 7.
The powder is dropped into the reservoir 8 through the reservoir 8, and the powder held at a predetermined layer height in the reservoir 8 is carried out by a spring feeder 9 whose rotation speed can be changed. Spraying section 1
0, the powder supply device is designed to scatter powder onto the molten steel surface of a mold 1 for a continuous casting machine, and the dispersion section 10 has an opening 29 at the tip and a plurality of dispersion holes 31a to 31c in a cylindrical section 30. The formed inner cylinder body 27 and the substantially trapezoidal slit 32 that changes the opening area of each of the dispersion holes 31a to 31c.
an outer cylindrical body 28 having slits 32a to 32c formed therein, and the slits 32a to 32c have trapezoidal opposing side angles α that become larger toward the upstream side, and an air supply pipe 33 is connected to the inner cylindrical body 27. This is what is being done. [Function] Powder 6 cut into fixed amount and transported
is transferred to the reservoir 8 by falling through the vertical pipe 7. The amount of powder is adjusted in the storage container 8 so that the layer height is approximately constant, and from there, the powder is conveyed horizontally by a spring feeder 9 to reach the dispersion section 10. The dispersion section 10 has an opening 29 at the tip of the inner cylinder 27 and dispersion holes 31a to 31c provided therein, and approximately the same amount of powder 6 is sprayed from each of them. When increasing or decreasing the amount of spraying by changing the rotation speed of the spring feeder 9,
The outer cylindrical body 28 in which the trapezoidal slits 32a to 32c are formed is rotated to
change the aperture area. At that time, the slit 32a
Since the crisscross angles of the opposite sides of the trapezoid of ~32c are formed to increase as αa, αb, and αc toward the upstream, the change in the opening degree of the dispersion hole on the upstream side increases,
The amount of spray from each spray hole is the same even at the rotational speed at that time. Moreover, since air is supplied into the inner cylinder body 27 from the air supply pipe 33, the inner cylinder body
7 is always maintained at positive pressure, and the spray holes 31a to 31
The powder can be more reliably spread from sources such as c. [Effects of the Invention] The present invention provides a dispersion unit for dispersing powder into a mold, which includes an inner cylindrical body having an open tip and a plurality of dispersion holes formed in the cylindrical portion, and an opening area of each dispersion hole. An outer cylindrical body in which a substantially trapezoidal slit is formed to change the trapezoid, and the slit has a trapezoid with a trapezoid having a larger crisscross angle on opposite sides toward the upstream side, and an air supply pipe is connected to the inner cylindrical body. Therefore, by changing the rotation speed of the spring feeder and rotating the outer cylindrical body, it is possible to change the area of all the spray holes and the amount of spray. At that time, the same amount of powder is sprayed from all the spray holes. Therefore, the desired amount can be evenly distributed and sprayed onto the molten steel surface, and the desired cooling and lubricating effects can be exerted without interruption. [Examples] Hereinafter, the present invention will be described in detail based on Examples. Figure 1 is an overall view of the powder supply device.
It is applied to continuous casting equipment that continuously casts billets, etc. The continuous casting machine includes a mold 1, a ladle 3 into which molten steel 2 is introduced, a nozzle 4 that guides the molten steel 2 from the bottom of the ladle 3 to the mold 1, and a nozzle 4.
It consists of a metal fitting 5 for connecting the billet and the ladle 3, a pinch roller (not shown) for pulling out the solidifying billet from the mold 1, and a cooling device for cooling the billet. A device for supplying powder 6 for oxidation prevention and lubrication of molten steel 2A into the mold 1 includes a vertical pipe 7, a reservoir 8, a spring feeder 9 whose rotation speed can be changed, and It has a dispersing part 10 formed at the tip. In this example, hopper 1 contains powder 6A.
1 is carried onto the second floor 12 by a crane or the like and installed on a pedestal 12a, and a powder quantitative cutting device 14 is connected to the hopper 11 via an expansion joint 13.
is connected. Powder quantitative cutting device 14
is driven by the rotation of the motor 15 being transmitted through the sprocket and chain. That is, a fixed amount of powder under the expansion joint 13 is cut out and conveyed by the spring feeder 16, which has a spiral spring built into its tubular body. Since the powder needs to be conveyed to the opening of the mold 1 at a different height from the lower end of the hopper 11, the outlet 16 of the spring feeder 16 is
A vertical pipe 7 is arranged directly below a. For example, two vertical pipes are provided as shown in FIG.
8 allows the direction of powder movement to be changed. This is to keep the height of the powder layer in the reservoirs 8A, 8B connected to the lower ends of each vertical pipe within a certain range. The vertical pipe 7 that drops the powder into the reservoir 8 is a flexible pipe made of nylon, for example.
can be easily connected and removed. A plurality of chains 19 are suspended within the vertical tube 8 and attached to a hanging support 20. The hanging body 20 is rotated by the power of a motor 21 (see FIG. 1) via a sprocket 22 (see FIG. 3a). The chain 19 is used to prevent powder from adhering to the inside of the vertical tube 7 and from growing and causing bridges. This is to ensure that when the pipe 7 is evacuated, the bending action of the vertical pipe 7 is not obstructed by being inside the pipe 7. Two rows of spring feeders 9 are installed at the bottom of the reservoir 8.
The spring feeder 9 and the reservoir 8 serve as a feeder 2 for supplying powder to the mold 1.
3. Spring feeder 9 is motor 2
4 [See Figure 1] rotates the sprocket 25, 2.
6, and the powder in the reservoir 8 is continuously discharged in fixed amounts. Note that when increasing or decreasing the supply amount to the mold 1, the motor 24
The rotation speed can be changed. Spring feeder 9
The reason why two wires are provided as shown in Figure 4 is that
This is because, when viewed in plan, the dispersing portions 10 at the tips of the spring feeders 9 need to be disposed opposite to each other so as to sandwich the nozzle 4 so that the supply to the molten steel surface is uniform around the nozzle 4. By the way, spraying section 1
0 is provided with, for example, four spraying locations, and approximately the same amount of powder is sprayed from all locations. Therefore, in this example, there are eight spraying locations on the molten steel surface, and the powder is evenly spread around the nozzle 4, and enough powder is constantly supplied to thinly cover the molten steel surface. By the way, the dispersion section 10 consists of an inner cylinder body 27 and an outer cylinder body 28, and as shown in FIG.
There is an opening 29 at the tip of the tube 7, and a plurality of dispersion holes 31 are formed in the cylindrical portion 30. In this example, three dispersion holes 31 are provided, all of which have, for example, the same width, but whose lengths can be changed. That is,
A substantially trapezoidal slit 32 for changing the opening area of the dispersion hole 31 is formed in the outer cylinder 28,
As shown in the developed view of the slits in FIG. 5, the slits 32a to 32c have trapezoidal trapezoidal trapezoid angles of αa, αb,
It is formed sequentially larger than αc. The inner cylindrical body 27 incorporates a rotating spring up to the opening 29, and the outer cylindrical body 28 rotates while surrounding the inner cylindrical body 27, so that the opening of the dispersion hole 31 is aligned with the slit 32. The area of the dispersion hole 31 can be set to a desired size according to the rotation of the outer cylinder 28. In addition, the selection of the crisscross angle of the opposite side of the trapezoid depends on the diameter of the inner cylindrical body 27 to be adopted, the wire diameter and pitch of the spring,
Although it differs depending on the distance between the spray holes, etc., once these are specified, the spray amount is determined depending only on the rotation speed of the spring feeder, and the spray amount from the opening 29 and each spray hole 31 is equal. was confirmed in the research conducted by the present inventors. For example, while the rotation of the spring feeder 9 is kept constant, the area of the spray holes 31a to 31c provided at desired intervals is changed until the amount of spray from each of the spray holes including the opening 29 becomes equal, and each spray hole in that rotation is changed. The area of the area was measured. The rotational speed of the spring feeder 9 was changed and the area of the spray hole for the same amount of spraying at that rotational speed was measured. By the way, when the spray holes have the same opening area, the amount of spray at the opening 29 at the tip is the largest,
There is a property that the amount of spraying decreases as one moves upstream in the powder conveyance path. The above-mentioned trapezoidal slit is intended to eliminate the difference in the amount of spray as much as possible. Once the diameter of the dispersion section 10 is determined, it is not easy to change the opening area of the opening 29, so it is assumed that it remains unchanged, and when examining the change in the hole area with respect to the rotation speed for each of the dispersion holes 31a to 31c, it is found that the above-mentioned outer cylinder body 28 This results in a geometric shape that looks like it was formed in . Therefore, if the width of the spray hole is kept constant, and the length of the hole is changed by the slit 32, the same amount of spray can be obtained at each rotation speed. Incidentally, it is necessary that the powder is always smoothly dispersed from each of the dispersion holes 31a to 31c, and in order to reliably maintain this, an air supply pipe 33 is attached to the inner cylindrical body 27. This is connected to an air source (not shown) and is designed to maintain positive pressure inside the inner cylinder 27 at all times. Of course, it is preferable that the pressure is at a level that does not cause the powder to generate dust, but it is convenient to select the air pressure so that it can be changed depending on the particle size and properties of the powder. The operation of the powder supply device to the mold for a continuous casting machine having such a configuration will be described below. A large amount of powder 6A is stored in the hopper 11 installed on the second floor 12, and the powder is deposited in the powder metering cutting device 14 via the expansion joint 13 due to the rotation of the spring in the spring feeder 16. It is cut out in quantitative order. When the rotational speed of the motor 15 is set high, the fixed amount of cutout increases. Its speed is controlled by a control signal from a separate control room. The powder that has reached the discharge port 16a at the tip of the spring feeder 16 is fed into the bifurcated duct 17, and is then passed through the damper 18.
Accordingly, it falls into one vertical pipe 7. The powder that has been cut into a fixed amount and transported is transferred to a storage container 8 so as to fall through a vertical pipe 7. The damper 18 is switched in response to a signal from the level sensor 34 attached to the reservoir 8, and the powder in the reservoir 8 is kept at a substantially constant layer height. The spring feeder 9 is driven by the motor 24, and a certain amount of powder according to the rotation speed of the spring feeder 9 is delivered to the scattering section 10.
It is transported horizontally until the From the dispersing part 10 into the mold 1, there are an opening 29 at the tip and dispersing holes 31a to 31c.
Powder is dispersed from a total of four locations, and the powder is evenly distributed on the molten steel surface. In addition, the powder is incorporated into the molten steel so as to be mixed with the molten steel that is continuously introduced from the ladle 3, and prevents oxidation of the molten steel 2A and promotes slipping between the molten steel that has begun to solidify and the mold 1, and separation from the mold. Ru. On the other hand, in the vertical tube 7, the chain 19 hangs down from the suspension member 20 and is rotated, so that the powder that has been conveyed in a fixed amount is stimulated by the movement of the chain and is continuously transported without clogging the vertical tube 7. and falls into the reservoir 8. Therefore, phenomena such as bridging and clogging and falling defects are avoided, and a fixed amount of powder can be transferred in the vertical tube 7, which is not easy to transport. By the way, when it is desired to increase the amount of powder supplied, the outer cylindrical body 28 of the dispersion section 10 is rotated, and the length of the dispersion hole 31 is lengthened by an amount corresponding to each. This is achieved by shifting the slit 32 toward the wider portion, and its spread is increased on the upstream side of the powder conveyance path. That is, since the slits are formed with different widths as shown in the developed view shown in FIG.
The rate of increase/decrease is different depending on a to 31b. However, since the rotational speed of the spring feeder 9 at that time is set so that the amount of powder to be spread from all the spreading points is approximately the same, there is no variation in the amount of powder spread from one spreading section 10. I almost never go out. Further, since compressed air is supplied into the inner cylinder body 27, the positive pressure thereof helps spread the powder. Note that the amount of powder supplied varies depending on the composition of the molten steel, the dimensions of the billet to be cast, etc., so the rotation speed of the spring feeder 9 may be adjusted.
Even if you change it in the range of 20 to 100%, you can get the same amount of spray each time. As an example, the case of a 12mm pipe is shown in the table below, and it can be seen that almost the same amount of spraying is achieved.

【table】

【table】 [Brief explanation of drawings]

Fig. 1 is an overall view of the powder supply device of the present invention applied to continuous casting equipment, Fig. 2 is a layout of the dispersion holes, etc. in the dispersion section, and Figs. 3a and b are enlarged front views of the vicinity of the vertical pipe. A side view, FIG. 4 is a diagram showing the arrangement of the powder spraying section around the nozzle, and FIG. 5 is a developed view of the trapezoidal slit. DESCRIPTION OF SYMBOLS 1... Mold, 2, 2A... Molten steel, 6, 6A... Powder, 7... Vertical pipe, 8... Reservoir, 9... Spring feeder, 10... Spreading part, 27... Inner cylindrical body, 28
...Outer cylindrical body, 29...Opening, 30...Cylinder part, 32...Slit, 33...Air supply pipe, αa, αb, αc...Opposing side angle.

Claims (1)

[Claims] 1. The powder that has been conveyed in a fixed amount is dropped into a storage container through a vertical pipe, and the powder held at a predetermined layer height in the storage container is carried out by a spring feeder whose rotation speed can be changed. This is a powder supply device that scatters powder onto the molten steel surface of a mold for a continuous casting machine from a dispersion section provided at the tip, and the dispersion section has an open tip and a plurality of dispersion holes. The cylindrical body includes an inner cylindrical body formed in a cylindrical portion, and an outer cylindrical body in which a substantially trapezoidal slit is formed to change the opening area of each of the dispersion holes. 1. A powder supply device for a mold for a continuous casting machine, characterized in that the corners are formed large and an air supply pipe is connected to the inner cylindrical body.