JPH0556221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for supplying a fixed amount of powder using gas and uniformly distributing it into a mold in continuous casting equipment.

[Prior art]

Continuous casting machines are currently being introduced worldwide in the steel industry. In continuous casting, it is essential to supply and scatter powder onto the surface of the molten steel in the mold that forms slabs, blooms, etc. for the purposes of lubrication between the slab mold copper plates, removal of impurities, heat retention, etc. in addition to oscillation. It is. In the conventional method, the lubricant was manually supplied and sprayed onto the surface of the molten metal in the mold, and in this case, the amount of spraying depended on human intuition, resulting in individual differences, and it was not always possible to achieve appropriate lubrication. There was also the problem of a poor working environment due to high heat and generation of powder dust. On the other hand, attempts have recently been made to automatically spread the powder without manual intervention, and a well-known method is a mechanical transportation/dispersion method using a spring feeder or the like.
This has become the mainstream. However, this method requires the supply distribution feeder to be installed in a narrow space between the tandate shoe molds, and is not particularly suitable for small cross-sectional sizes due to the limited installation space determined by the required size of the feeder and lack of flexibility. Furthermore, there were other problems such as poor workability around the mold and low reliability of the device due to thermal problems. A pneumatic method has also been tried, and the conventional method is to harden the powder into a plug shape (see Figure 10B) to prevent dust and reduce the cost of pneumatic gas.
The plug-shaped powder was sequentially pumped with pressurized gas. However, the contact resistance between the plug-shaped powder and the inner surface of the feeding path is large, causing clogging in the piping, and compressed gas is intermittently ejected into the mold from a nozzle, causing the powder in the mold to roll up and generate dust. For this reason, it has not been put into practical use for powder dispersion into molds.

[Objective of the Invention] In order to solve these problems, the present invention uses a pneumatic conveyance system that uses floating transportation to feed granular powder at a constant rate using a small amount of carrier gas, and uniformly disperse it inside the mold without generating dust. The present invention provides a device that supplies powder with good workability.

[Structure and operation of the invention] The present invention disperses powder, supplies it to a feeding pipe, and transports the powder while floating while surrounding and dispersing it using a small amount of airflow that has a drawing effect in the feeding direction. It reduces the contact resistance with the inner surface of the tube and allows the powder to be sent slowly. In this way, it becomes possible to spray the powder onto the mold surface using the spray nozzle without generating dust.

[Example] The present invention will be explained below using an apparatus shown in the drawings.

FIG. 1 shows an overall view of the apparatus according to the present invention [A is for bloom billets, B is for slabs], and 1
is a tank that is sealed to the extent that moisture absorption is prevented by blowing _N2 into it, and powder 12 is stored inside, and the top
N ₂ conduit 2 is connected, and N ₂ gas from which moisture has been removed flows through the powder in tank 1 from above the tank, and N ₂ gas is supplied to prevent the powder from hanging on the shelf.
Gas is ejected downward into the tank. A horizontal support plate 13 is attached to a portion surrounding the lower end opening of the conduit 2, and the support plate 13 supports the powder and prevents the powder from hanging on the shelf.
Additionally, a load cell 6 is installed in the tank 1, making it possible to grasp the amount of powder used. Connected to the lower part of the tank 1 are an open/close valve 3 and an ejector 4 for continuously discharging and feeding a required amount of powder. 5 is a powder feeding pipe connected to the ejector 4, and 7A and 7B are for floatingly transporting the powder passing through the feeding pipe 5 or having passed through the ejector 4 in the feeding direction by an air current having a drawing effect. 8 is a spraying nozzle for continuously dispersing powder onto the surface of the mold, 9 is a pressure regulator, 10 is the mold, and 11 is an injection nozzle, which is disposed at the center above the surface of the mold.

FIG. 2 shows a detailed sectional view of the on-off valve 3 and the ejector 4, where the on-off valve 3 is a powder passage 31 and a valve 3 disposed between the passage and the frame 32.
3, a conduit 35 for sending pressurized gas to the airtight chamber, and a three-way solenoid valve 37 and a two-way solenoid valve 38 that open and close in response to a signal from a timer 36 shown in FIG. ing.

The on-off valve 3 operates by opening the three-way solenoid valve 37 in the A direction and closing the two-way solenoid valve 38 to open each airtight chamber 34.
Pressure gas is introduced into the valves 33, and the valves 33 are brought into pressure contact as shown by broken lines in the figure, thereby closing the passage 31. Three-way solenoid valve 37
When the two-way solenoid valve 38 is opened in the B direction, the pressure gas in the airtight chamber 34 is sucked outward, and the valve 33 is opened. The ejector 4 includes a powder dispersion member 42 attached to a holder 41, a powder reservoir 43 screwed to the upper part of the holder 41, and an injector inner tube 71 attached to the lower part of the holder 41.
It is equipped with As shown in FIG. 3 ((A) is an enlarged sectional view, (B) is a plan view), the dispersion member 42 has a conical projection 45 protruding from the center thereof, and a plurality of through holes around the conical projection. A hole 46 is provided. The top 45a of the conical projection 45 is located at or below the lower end of the discharge port 47. 48 is a tightening nut for fixing the storage tank 43 to the holding body 41, and 49 is an O-ring for preventing outside air from entering inside the holding body 41.

FIG. 4 shows a detailed view of the injectors 7A and 7B for floatingly transporting powder by airflow having a drawing effect in the feeding direction, 71 is an inner pipe, 72
73 is an outer pipe, and 73 is a pressure gas introduction pipe provided in the outer pipe 72. The inner diameter of the outer pipe 72 is enlarged toward the conduit 73, and the inner pipe 71 is inserted into the enlarged part. A pressure gas passage 74 is formed surrounding the pipe 71, and a ring-shaped nozzle 75 as a pressure gas ejection port is formed at the tip of the passage 74. Note that the inner diameters of the inner tube 71 and the outer tube 72 are approximately the same.

The pressure gas supplied from the introduction pipe 73 is ejected from the ring-shaped nozzle 75, and this ejection causes the inner pipe 71 to
The powder 12 inside is sent to the outer tube 72. Pressure gas ejected from the ring-shaped nozzle 75 flows into the outer tube 72.
The air flow along the inner surface of the outer tube 7
The powder sent through the inside of the tube 2 is sent while being surrounded by an air current, hardly making contact with the inner surface of the outer tube, and has very low contact resistance with the inner surface. Therefore, the powder can be fed while minimizing a decrease in the powder feeding speed, and wear of the outer tube 72 and the feeding tube 5 can be prevented.

FIG. 5 shows an enlarged detailed view of a dispersion nozzle (multi-hole nozzle) for continuously dispersing powder onto the mold surface (A is a plan view, B is an AA cross-sectional view of A);
Reference numeral 81 indicates a nozzle main body, and reference numeral 82 indicates a plurality of discharge ports opening in the longitudinal direction of the main body.
As shown in FIG. 1, the nozzle 11 is disposed surrounding the injection nozzle 11 and at the center of the hot water surface. The powder is evenly discharged from the discharge port 82 in the longitudinal direction,
The mold 10 falls to the center of the molten metal surface and gradually melts.
The melt moves evenly toward the inner surface of the mold, and by the time it reaches the edge of the mold, it is completely melted and supplied to the surface of the slab.

In this way, the powder is continuously dispersed at the center of the hot water surface, so there is no fluctuation in the dissolution of the powder at the edge of the mold, and completely dissolved powder can be constantly supplied. For multi-hole nozzles, the discharge flow rate is 1m/
When the amount is less than s, the same amount of powder is sprayed directly below from each nozzle as shown in FIG. 7A, and is uniformly spread on the mold surface. Therefore, it can be said that this nozzle is suitable not only for slab slabs but also for small cross-sectional size or irregularly shaped slabs.

Figure 6 is an enlarged detailed view showing another example of a dispersion nozzle (slit nozzle) [A is a plan view, B is a side view]
81 is a nozzle body, and 82 is a slit-shaped discharge port. In the slit nozzle of this example, the seventh
As shown in Figure B, powder is ejected at an angle in the feeding direction, which is disadvantageous for molds with small cross-sections, but it can be applied to molds with large or long cross-sections such as slabs, and the powder can be ejected from the nozzle. Since it can be sprayed forward, it is convenient when spraying mainly around the injection nozzle where it is difficult to install the nozzle close to it.

Next, a series of operations will be explained. First, based on the amount of powder to be supplied into the mold 10 per unit time, the timer 36 determines the opening/closing timing of the opening/closing valve 3, that is, the three-way solenoid valve 37 and the two-way solenoid valve 38.
The opening/closing timing of the storage tank 43 is set, and the storage tank 43 is equipped with a discharge port 47 having a diameter capable of discharging a desired amount of powder. Next, when the pressure gas opens the valve 13 and turns on the switch (not shown) of the timer 36, the inside of the tank 1 is pressurized and the opening/closing valve 3 repeats opening and closing at the set timing. By opening the on-off valve once, the storage tank 43 is almost filled with powder. Storage tank 43
The powder is discharged from the discharge port 47, dispersed by the conical protrusion 45, and falls from the plurality of through holes 46 in a dispersed state. This falling powder is forced into the feed pipe 5 by the pressure gas jetting out from the injector 7A. Powder is sent in a floating state inside the feeding tube, but if the tube is long and the pressure loss inside the tube is large, the powder inside the feeding tube 5 is further fed by the injector 7B. In the injector 7B, the powder is accelerated and suspended while being surrounded and dispersed by the airflow that has a drawing effect in the direction in which the feed pipe advances. Therefore, the powder can be fed at a low speed, and the powder can be evenly dispersed from the spray nozzle 8 into the mold 10 without generating dust. As soon as the inside of the storage tank 43 becomes empty, the on-off valve 3 is opened for a predetermined period of time, and the storage tank 43 is opened in the same manner as described above.
is filled with powder, and the powder is automatically fed and dispersed in the same manner.

Further, the injector 7 may be provided with a nozzle 75 that opens in the powder feeding direction as shown in FIG.

Next, a specific example of powder dispersion using the apparatus of the embodiment will be explained.

The amount of powder used in continuous casting is usually 0.5 to 1
Kg/ton of molten steel. Currently, the capacity of each part is φ0.5
Using granular powder of ~1.2 mm, the internal volume of the storage tank 43 shown in FIG. 2 was set to 135 cm ³ , and the amount of powder discharged was varied by turning on and off the on-off valve 3 as shown in FIG. 2, for example. Intermittent cycle ○ input 4
Set to 15 seconds + 15 seconds = 19 seconds/1 cycle, 25
Kg/h of powder was fed.

Next, as a floating transportation method for powder, injectors shown in Figure 4 are installed every 5 to 10 m, the nozzle diameter is φ10 mm, and N ₂ is used as a carrier gas at the original pressure.
0.3~0.5Kg/ ^cm2 , injector 7A, 7B
The powder was transported floating in the feed pipe with a total gas flow rate of 32/min.

Next, apply this powder to SGP15A using nozzle φ7mm
8 pieces/200mm x multi-hole nozzles installed in 2 directions (5th
(Figure) was used to uniformly spread the powder over the top of the mold. Figure 9 shows the spraying situation for 20 minutes. In addition, the flow velocity of the carrier gas ejected from the porous nozzle is 0.8 to 0.9 m/s.
The powder sprinkled on the surface of the mold did not roll up, and there were no environmental problems. On the other hand, if a slit nozzle is used instead of a multi-hole nozzle, as shown in Figure 6B, when the discharge flow velocity at the slit nozzle part is within 1 m/s, it is possible to tilt the carrier gas in the direction of travel with the same width as the slit width. If the injection nozzle 11 is placed between the injection nozzles 11 as shown in FIG. 1B, the powder will be spread around the nozzle as well.

The method of the present invention is a pneumatic conveying method that exhibits the floating transport form shown in Figure 10A, and unlike the conventional method, the flow velocity in the pipe is greatly reduced, and the flow rate is uniformly distributed over the mold surface without clogging the pipe. This makes spray supply possible.

Powder that is a mixture of base material, aggregate, and fine carbon powder, granulated mixture, granulated mixture of these components, melted and solidified after cooling, and As a result of using the powdered, granulated, and granular materials mixed with nitride instead of fine carbon powder and feeding and distributing them according to the method of the present invention, no clogging occurred in the feeding pipe. Ta. In addition, the granulated and granular products had very little granulation during feeding.

On the other hand, in the conventional pneumatic feeding method, as shown in the example of FIG. 11, powder is cut out in a fixed amount from a hopper 90 through a Kinyon pump 91 (or rotary valve), and the powder is fed pneumatically through a carrier gas port 92 attached to the output side of the Kinyon pump. It is supplied and sprayed from the nozzle 93 onto the mold surface. However, in the case of this method, it is necessary to send at a source pressure of 2 to 7 kg/cm ² , and in that case, as shown in Figure 10B, a plug transportation form is used,
Powder 12 and carrier gas CG exist alternately,
The gas layer becomes thinner toward the tip of the transport, and the pressure increases. Therefore, after the powder is spread, the compressed gas blows out all at once, causing the spread powder to be stirred up and causing dust. Also, due to the large pressure loss, it is easy to get clogged. In addition, when the gas amount is increased to 15 m/s in the pipe flow velocity in order to adopt a floating transportation mode, the gas amount increases and the discharge speed from the nozzle 93 increases, and in this case as well, the dispersed powder will be rolled up. Furthermore, high gas volume and gas pressure, as well as frequent contact with mechanical parts such as Kinyon pumps, can cause the powder to become powder.

〔Effect of the invention〕

Conventionally, it was not possible to feed and spread the powder satisfactorily, so most of the feeding during casting was done manually, and it was not possible to supply the appropriate amount of powder. Although surface defects often occurred, the present invention can solve the above problems, suppress the wear of the feed pipe, and also relieve the harsh casting work that involves high temperatures and dust. This has a significant effect on improving the quality of slabs and the working environment.

In addition, the device of the present invention has a simple configuration, so there is no need to worry about breakdowns, and maintenance is easy.Furthermore, since it is compact, it does not interfere with work, and can be used not only for slab slabs but also for small cross-sections. It is even more effective in the case of sized slabs or irregular shaped slabs, and can be the most effective means of recent automation and mechanization.

[Brief explanation of the drawing]

1A and B are overall sectional views showing an example of the device of the present invention, FIG. 2 is a partial detailed sectional view of FIG. 1, and FIG. 3 is a partial detailed view of FIG. A plan view, FIG. 4 is a partial detailed sectional view of FIG. 1, FIG. 5 shows an example of the spray nozzle, A is a plan view, B is a sectional view taken along line A-A of A, and FIG. 6 is a partial detailed sectional view of FIG. 7A and B are side views showing the spraying mode of the spraying nozzle, and FIG. 8 shows another example of the jetting of pressurized gas into the feed pipe. FIG. 9 is a perspective view showing the state of spraying from the spray nozzle to the upper surface of the mold. FIG. 10 is a cross-sectional view illustrating the mode of transportation, where A is the floating mode of transportation, B is the plug mode of transportation, and FIG. is a schematic diagram showing a conventional pneumatic feeding system. In the figure, 1 is a tank, 2 is a conduit, 3 is an on-off valve, 4 is an ejector, 42 is a dispersion member, 43 is a storage tank, 45 is a conical projection, 46 is a through hole, 47
is a discharge port, 5 is a powder feeding pipe, 6 is a vibrator, 7A, 7B are injectors, 8 is a powder dispersion nozzle, 10 is a mold, 11 is an injection nozzle,
12 is powder, 61 is a spout, and 75 is a ring-shaped nozzle.

Claims (1)

[Claims] 1. A tank 1 that stores powder, and an on-off valve 3 that discharges and feeds the powder stored in the tank 1.
and an ejector 4, a feed pipe 5 for pneumatically feeding the powder discharged from the ejector 4 via an injector 7, and a spray nozzle 8 for dispersing the powder. (b) The on-off valve 3 is connected to the lower end of the tank 1 and is equipped with a pressure gas conduit 2 that opens downward and a horizontal support plate 13 that is provided around the conduit 2. A pinch type valve 33 provided in the passage 31, a conduit 35 for sending pressurized gas to an airtight chamber 34 formed on the back side of the valve 33, and a conduit 35.
(c) The ejector 4 is provided with a three-way solenoid valve 37 and a two-way solenoid valve 38 that open and close in response to a signal from a timer 36. A dispersion tank 43 having a conical protrusion 45 in the center and a plurality of through holes 46 formed around the conical protrusion 45, which is screwed onto the reservoir 43 and installed below the discharge port 47. Holder 41 with member 42 installed inside
(d) The injector 7 is provided with a nozzle 75 provided at the lower end of the holder 41 and in the middle of the feed pipe 5 and opened in the powder feeding direction; (e) The spray nozzle 8 is provided with a A powder scattering device for continuous casting, characterized in that the tip is closed and provided with a large number of holes or slit-shaped discharge ports 82 in the longitudinal direction.