JPH027864Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention uses a vacuum ladle degassing device for steelmaking equipment, in which inert gas in the piping that pumps inert gas into molten steel may spout out when the ladle is removed, posing a danger to workers. This invention relates to inert gas supply piping equipment that does not scatter dust and cause it to adhere to the surrounding area. FIG. 1 is a schematic front view showing an example of a conventional vacuum ladle degassing apparatus, and the structure of this figure will first be explained. Reference numeral 1 denotes a container body, 2 a lid that covers the container body 1 with a sealing material 3 interposed therebetween, and a vacuum container 4 is constituted by these. 5 is a crane (not shown)
This is a ladle that is carried by being suspended from the container, and is carried into the container body 1 with the lid 2 removed, or carried out of the container body 1. 6 is a porous plug attached to the bottom of the ladle 5. Reference numeral 7 denotes a gas path connecting device consisting of a fitting 8 and a fitting 9, which are configured to be separable and detachable, and the fitting 9 is arranged near the upper edge inside the container body 1. Fitting 8 can be any attachment means 10
The fitting 8 and the porous plug 6 are connected to each other via an air pipe 11 attached to the ladle 5. Reference numeral 12 denotes an inert gas supply source such as argon gas, which includes an air supply pipe 13, a supply gas amount control device 14, an air supply pipe 15, a shutoff valve 16, and an air supply pipe 1.
It is connected to a joint 9 via 7. An exhaust device 18 such as a steam ejector is configured to make the inside of the vacuum container 4 a negative pressure via an exhaust duct 19. 20 is an oxygen blowing lance provided through the lid 2, and 21 is a scaffolding board provided near the upper end of the inner wall of the container body 1. Next, a method of handling the vacuum ladle degassing device shown in FIG. 1 will be explained. With the lid 2 open, the ladle 5 containing the molten steel 22, which has been suspended and transported by a crane, is installed in the vacuum container 4, and the hand of a worker (not shown) with one foot on the scaffolding board 21. By operation, the fitting 9 is connected to the fitting 8, and the cutoff valve 16 is opened to remove inert gas from the inert gas supply source 12.
6. It is jetted into the molten steel 22 via the gas path connecting device 7, the air pipe 11, and the porous plug 6, and is stirred. Thereafter, the lid 2 is closed, the inside of the vacuum container 4 is made negative pressure by the exhaust device 18, and oxygen is blown onto the surface of the molten steel 22 from the oxygen blowing lance 20.
2 degassing refining is being carried out. When degassing and refining the molten steel 22 like this, in order to blow out the inert gas from the porous plug 6, it is necessary to feed the inert gas at a gas pressure higher than the head pressure of the molten steel 22 in the ladle 5. . In the case of a normal ladle,
Since the height of the molten steel 22 is about 2.5 m, the pressure of the inert gas passing through the gas path connecting device 7 is about 2.5 m.
Atmospheric pressure or higher is required. When the degassing refining work is completed, the oxygen blowing of the oxygen blowing lance 20 is stopped, the operation of the exhaust device 18 is stopped, the inside of the vacuum container 4 is brought to atmospheric pressure, the lid 2 is removed, and the shutoff valve 16 is stopped. However, the head pressure of the molten steel 22 in the ladle 5 (approx. 2 atmospheres (hereinafter referred to as residual pressure gas) is applied. In such a situation, if a worker places one foot on the scaffolding board 21 and manually disconnects the gas path connecting device 7 consisting of the fittings 8 and 9 using a monkey wrench, pipe wrench, etc., the The residual pressure gas in the trachea 11, the gas path connecting device 7, and the air pipe 17 is ejected from the gap created between the fittings 8 and 9, and the residual pressure is suddenly released. The accumulated dust scatters and enters the eyes and noses of workers, which is unfavorable in terms of safety and working environment. Fig. 2 is a schematic front view showing another example of a vacuum ladle degassing device (see Utility Model Publication No. 55-2026). Parts common to those in Fig. 1 are given the same reference numerals and their explanations are given below. Omitted. This figure will be explained. Support bases 24, 24 on which trunnions 23, 23 of the ladle 5 are placed are provided at the bottom of the container body 1. In FIG. 2 and FIG. 6, which is a detailed sectional view thereof, the shutoff valve 16
The ventilation pipe 17 extends along the inner wall and bottom wall of the container body 1, ascends along the support base 24 of the other end, and has an upward opening 25 on the trunnion support surface on the upper surface of the support base 24. The air supply pipe 11 from the porous plug 6 has a downward opening 26 on the lower surface of the trunnion 23. A loop-shaped groove 27 is provided on the upper surface of the support base 24 surrounding the upward opening 25, and a loop-shaped packing 2 is provided in the loop-shaped groove 27.
8 is fitted. Therefore, the ladle 5 is placed on the support base 24.
When the trunnion 23 is placed, the loop-shaped packing 2
The upper and lower surfaces of 8 are hermetically pressed against the trunnion 23 and the bottom of the groove 27 to form the gas passage communication device 7. After the molten steel 22 is vacuum degassed and refined by the same method as shown in FIG. The dust is ejected from between the holes, scattering the dust that has accumulated in the surrounding area, and causing detachment and damage to the packing 28, which shortens the life of the packing. Next, the gas supply control device in the conventional device explained with reference to FIGS. 1 and 2 will be described in detail.
When operating the gas supply control device in its immediate vicinity, a simple float-type controller (not shown) that can simultaneously adjust the pressure value and flow rate value of the inert gas flowing through the air supply pipe 13 is provided. It was often used. However, recently, methods have been adopted in which pressure and flow rate are controlled by remote control. FIG. 3 is a diagram showing the principle of this process. A flow rate signal 30, a temperature signal 31, and a pressure signal 32 are input into a computing unit 33 as electrical signals, and a pressure controller 34 is inputted from these signals to correspond to the set pressure and flow rate values. Methods for controlling the flow rate controller 35 are becoming common. Reference numeral 14 indicates the entire supply gas amount control device. FIG. 4 is a schematic front view showing an embodiment in which the inert gas supply piping equipment according to the present invention is applied to the vacuum ladle degassing apparatus of FIG. 1 or 2, and FIG. 4 will be described below. Structures that are the same as those in FIGS. 1 and 2 are designated by the same reference numerals as in FIGS. 1 and 2, and their explanation will be omitted. 36 is an exhaust pipe provided in the air supply pipe 17 between the cutoff valve 16 and the container body 1, and is provided with a residual pressure release valve 37. With the residual pressure release valve 37 closed, the cutoff valve 16 is opened to perform degassing refining work. When the degassing refining work is completed, the shutoff valve 16 is closed and the residual pressure release valve 37 is opened.
The residual pressure gas in the gas path connecting device 7, the air pipe 11, the air pipe 17, and the exhaust pipe 36 is released and becomes atmospheric pressure. Thereafter, the gas path connecting device 7 is disconnected (see FIGS. 1 and 2). In this case, the gas path connecting device 7
Since the internal pressure is at atmospheric pressure, residual pressure gas does not blow out from the gap between the gas path connecting devices 7, which are each configured like the conventional ones shown in FIGS. The gasket 28 is not damaged unlike the conventional one shown in FIG. As mentioned above, by adopting the present invention, the conventional problems have been solved, and especially in the connection method using a packing in the trunnion part as shown in the example in Fig. 2, the service life of the packing has been improved by about 5 times compared to the conventional method. Ta. Therefore, the following table shows comparative work data when implementing the conventional method, the improved method according to the above-mentioned Utility Model Publication No. 55-2026, and the present invention.

[Table] Note that the reason why the installation position of the residual pressure release valve 37 is limited to outside the vacuum vessel 4 in the pipeline between the cutoff valve 1 and the porous plug 6 is because the installation position inside the vacuum vessel 4 is limited to If selected, the temperature will be high during vacuum refining, and the residual pressure release valve 37
This is because it is not a desirable location for installation. In addition, in the case of the present invention, the shutoff valve 16 and the residual pressure release valve 3
If you pay attention to the operation with 7, it is characteristic that it always operates in the opposite direction. That is, while gas is being supplied, the shutoff valve 16 must be open, and the residual pressure release valve 37 must be closed, and when the gas supply is stopped, the shutoff valve 16 must be closed. Yes, the residual pressure release valve 37 must be open. Therefore, by adopting the present invention, the signals of the shutoff valve 16 and the residual pressure release valve 37 are combined, and by incorporating a mechanism that always operates in reverse, it is possible to further improve safety and workability. Incidentally, instead of providing the cutoff valve 16 and the residual pressure release valve 37 independently, an integrated plunger valve 38 as shown in FIG. 5 is provided, and for example, an electric signal from the calculator 33 in FIG. 3 is sent to the solenoid S. By doing so, it is also possible to reliably switch between the supply from the supply gas amount control device 14 and the gas discharge port shown by the arrow 29. 5A and 5B show the state in which the plunge valve 38 is switched mutually.

[Brief explanation of the drawing]

Figure 1 is a schematic layout diagram when an input joint is used for gas piping in a conventional device, Figure 2 is a schematic layout diagram when the gas piping is automatically connected/disconnected at the trunnion support in a conventional device, and Figure 3 is a conventional diagram. A diagram of the electric control device of the device, FIG. 4 is an embodiment of the present invention, FIG. 5 is a vertical sectional view showing an embodiment of the integrated switching valve, and FIG. 6 is a diagram showing the right trunnion and It is a partially detailed sectional view of the right support base. 1... Container body, 2... Lid, 3... Sealing material, 4
... Container container, 5 ... Ladle, 6 ... Porous plug, 7 ... Gas path connecting device, 8 ... Fitting, 9 ...
Joint, 10... Attachment means, 11... Air pipe, 12
...Inert gas supply source, 13... Air pipe, 14...
...supply gas amount control device, 15... air pipe, 16...
...Shutoff valve, 17...Air pipe, 18...Exhaust device,
19...Exhaust duct, 20...Oxygen blowing lance,
21... Scaffolding board, 22... Molten steel, 23... Trunnion, 24... Support base, 25... Upward opening, 26...
...Downward opening, 27...Concave groove, 28...Putskin,
29...Arrow, 30...Flow rate signal, 31...Temperature signal, 32...Pressure signal, 33...Calculator, 34
...Pressure regulator, 35...Flow rate regulator, 36...
Exhaust pipe, 37... Residual pressure release valve, 38... Plunger valve, S... Solenoid.

Claims (1)

[Scope of utility model registration request] In a vacuum ladle degassing device for degassing and refining molten steel in the ladle by installing a ladle equipped with a porous plug at the bottom in a vacuum vessel, between the gas supply control device and the gas supply pipe connection device. A vacuum installation characterized in that the ventilation passage is provided with a valve device that selectively communicates the ventilation passage with either the gas supply control device or the atmosphere opening passage, so that the ventilation passage can also communicate with the atmosphere opening passage. Gas supply piping equipment for pot degassing equipment.