JPS5937715B2 - Pressure pouring equipment for casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting method in which a predetermined gas pressure is applied to molten metal, such as ductile cast iron (also referred to as spheroidal graphite cast iron), stored in a furnace body, and the molten metal is poured into a mold. This relates to a pressurized pouring device.

FIG. 1 is a schematic diagram showing a conventional pressurized pouring device for casting of this kind, in which reference numeral 2 has an inlet portion 4 and an outlet portion 5 connected to the bottom in a siphon shape, and a refractory material (not shown). The furnace body 2 is lined with iron, and a molten metal 1 of, for example, ductile cast iron is stored in the furnace body 2.

3 is attached to the bottom of the furnace body 2, and serves to keep the molten metal 1 warm;
and an induction heating section for raising the temperature; 6 is a furnace lid that airtightly closes the upper opening of the furnace body 2 via a backing (not shown);
Reference numeral 7 denotes a pressurized gas pipe that passes through the furnace lid 6 and communicates with the inside of the furnace body 2, and an exhaust solenoid valve 8 and an air supply solenoid valve 9 are attached to this pressurized gas pipe 7. There is.

10 is a pressurized gas source of a predetermined pressure made of an inert gas such as nitrogen gas or argon gas provided on the side of the air supply solenoid valve 9, and 11 is a pressure provided on the outlet side of this pressurized gas source 10. It is a control valve.

Since the conventional pressurized pouring device for casting is configured as described above, by energizing the solenoid of the exhaust solenoid valve 8, this exhaust solenoid valve is closed and the pressurized gas pipe γ is closed. After isolating the air from the atmosphere, the pressure setting of the pressure control valve 11 is set to "0", and the solenoid of the air supply solenoid valve 9 is energized to introduce pressurized gas from the pressurized gas source 10 into the furnace body 2. Try to get it.

Next, by rotating the pressure setting handle of the pressure control valve 11 to gradually increase the set pressure of the pressurized gas flowing in the pressurized gas pipe γ, the molten metal 1 in the furnace body 2 will be When the molten metal surface is pressurized by the pressurized gas, it rises in the inlet port 4 and the tap 5, and overflows from the pouring port 5a formed at the top of one tap 5. The metal is then poured into a ladle or mold.

When the predetermined amount of molten metal is poured, the exhaust solenoid valve 8
The solenoid is deenergized and opened to the atmosphere, and
Since the solenoid of the air supply solenoid valve 9 is deenergized and closed, the pressurized gas in the furnace body 2 is discharged from the exhaust solenoid valve 8 into the atmosphere.

Note that the closing operation of the exhaust electromagnetic valve 8 is normally delayed by a short period of 2 to 3 seconds after the input of the closing signal, but this is because the pressure inside the furnace body 2 is not increased for a while. Needless to say, this is to prevent the magnesium component of the molten metal 1 of ductile cast iron from being oxidized by oxygen in the atmosphere by leaving an inert gas such as nitrogen gas or argon gas.

When the amount of molten metal 1 in the furnace body 2 decreases by pouring metal from the pouring port 5a as described above, the solenoid valve 9 for air supply is opened while lowering the set pressure of the pressure control valve 11, and the inlet port 4 is opened. The molten metal 1 is replenished from the upper opening.

Note that when replenishing the molten metal 1, it is necessary to lower the set pressure of the pressure control valve 11 so that the molten metal does not overflow from the pouring port 5a, and the pressurized gas in the furnace body 2 is supplied through a pressurized gas pipe. It passes through line 7 and is discharged into the atmosphere from the exhaust port of pressure control valve 11, so that the pressurized gas pressure in pressurized gas line 7 and furnace body 2 is maintained at a set pressure. .

However, since the pressurized gas discharged in this way contains vapor of metallic magnesium evaporated from the molten metal 1, when this is discharged into the atmosphere from the exhaust port of the pressure control valve 11, Combines with oxygen in the atmosphere,
This metallic magnesium often burns, causing burnout of the diaphragm and backing of the pressure control valve 11, increasing maintenance costs, and the pressure control valve itself also has the disadvantage of being very dangerous.

Furthermore, if a pipe is connected to the exhaust port in order to prevent combustion at the exhaust port, the pipe is thin, resulting in a large pressure loss due to exhaustion, which also has the drawback of significantly reducing the control ability of the pressure control valve.

This invention was made with attention to this point, and by accommodating a pressure control valve in a sealed box into which an inert gas can be supplied, the pressure in the pressurized gas discharged from the pressure control valve is The object of the present invention is to provide a pressurized pouring device for casting in which metallic magnesium is prevented from burning at the exhaust port of this pressure control valve.

That is, although FIG. 2 shows one embodiment of the present invention, the same reference numerals as those in the above-mentioned conventional device (FIG. 1) refer to the same constituent members, and the explanation thereof will be omitted.

11a is a valve stem of the pressure control valve 11 having the bundle 11b; 11c is a plurality of exhaust ports of the pressure control valve 11; 12 is a valve stem 11a having the bundle 1b; This is a hermetically sealed box that protrudes to the outside in an airtight manner, and the inside and outside of this hermetic box 12, the penetration part of the pressurized gas pipe 7 connected to the pressure control valve 11, and the penetration part of the valve stem 11a are airtight. A banking 15 for sealing is attached.

Reference numeral 16 indicates an air supply pipe for feeding the pressurized gas flowing through the pressurized gas pipe 7, that is, an inert gas such as nitrogen gas or argon gas, into the sealed box 12 via the supply pipe 13; This is an exhaust pipe that discharges inert gas into the atmosphere.

According to this invention, as described above, inert gas can be supplied into the sealed box 12 housing the pressure control valve 11, so that when the prescribed pouring of metal into the ladle or mold is completed, the furnace When the pressure inside the pressure control valve 11 is reduced, the metal magnesium contained in the pressurized gas discharged from the exhaust port N1c of the pressure control valve 11 is not combusted at this exhaust port N1c, but is combusted at the outlet of the exhaust pipe 14. , the diaphragm and backing of the pressure control valve 11 do not burn as in the past, and failures of the pressure control valve 11 can be prevented, reducing maintenance costs and improving the operation rate of the pouring equipment. It has the effect of significantly improving

In addition, since the inside of the sealed box 12 is constantly pressurized by supplying pressurized gas, that is, inert gas, from the air supply pipe 16, 1.
Air may enter the sealed box 12,
Therefore, there is also the effect that there is no risk of so-called "backfire" phenomenon occurring within the closed box 12.

Further, according to the present invention, the exhaust port of the pressure control valve 11 is open in the sealed box 12, and the diameter of the exhaust pipe 14 can be freely increased, so there is no pressure loss due to exhaust. Unlike the conventional case, the control ability of the pressure control valve does not deteriorate.

Note that FIGS. 3 to 5 all show other embodiments of the present invention, and FIG. 3 shows one in which the pressure control valve 11 can be remotely controlled by an electric motor 11d, and FIG.
The figure shows that the pressure control valve 11 is pilot-operated by a pilot pipe 11e, and FIG. The operation and effect of each of these embodiments is exactly the same as that of the above-mentioned embodiment.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing a conventional pressurized pouring device for casting, Fig. 2 is a sectional view showing an embodiment of the present invention, and Figs.
The figure is a sectional view showing another embodiment of the invention. In the drawing, 1 is the molten metal, 2 is the furnace body, 4 is the inlet, 5 is the outlet, 5a is the pouring port, 7 is the pressurized gas pipe, 10 is the pressurized gas reducer, 11 is the pressure control valve, 12 is a sealed box, 13 is an air supply pipe, 14 is an exhaust pipe, and 16 is an air supply pipe. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A pressure control valve for pressurized gas that pressurizes the molten metal in a furnace body having an inlet port and a tap outlet is housed in a sealed box that can supply inert gas. A pressurized pouring device for casting featuring the following. 2. The pressurized pouring device for casting according to claim 1, wherein an inert gas such as nitrogen gas or argon gas is used as the pressurized gas. 3. The pressurized pouring device for casting according to claim 1, characterized in that a pressure control valve is provided in the pressurized gas pipe connecting the furnace body and the pressurized gas source. 4. The pressurized pouring device for casting according to claim 1, wherein the pressurized gas flowing through the pressurized gas pipe is supplied into a closed box. 5. The pressurized pouring device for casting according to claim 1, wherein the closed box is provided with an exhaust pipe for discharging the pressurized gas supplied into the closed box.