JPH0366468A - Pressure molten metal pouring coreless crucible type induction furnace - Google Patents

Abstract

PURPOSE:To secure an accurate amount of pouring molten metal by storing a coreless crucible type induction furnace in an airtight container capable of impressing a pouring pressure, opening a molten metal pouring siphon under the container and providing a molten metal receiving chamber. CONSTITUTION:The coreless crucible type induction furnace 4 is stored in the container 7 provided with an airtight cover 12 and connected with a molten metal pouring pressure tube 14. A molten metal pouring siphon 15 wherein the upper end is connected with a molten metal pouring chamber 17 and the lower part is opened and a molten receiving siphon 19 wherein the upper end is connected with the molten metal receiving chamber 20 are installed through the respective airtight covers. Further, the upper end to which the molten metal receiving chamber is opened is set at a position higher than the molten metal pouring level of the molten metal pouring chamber 17 at a molten metal pouring time. In this way, the whole molten metal in the crucible can be poured, the molten metal can be received or melting can be begun from cold material and an accurate amount of pouring molten metal can be secured.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a pressurized pouring type crucible-shaped coreless induction device used for pouring an appropriate amount of molten metal into a mold for casting. Regarding furnaces.

[Conventional technology]

Induction melting furnaces are broadly classified into groove induction furnaces and coreless induction furnaces. The former groove-type induction furnace is based on the same principle as a transformer, with a primary winding wound around a closed iron core, and the molten metal in a groove made of refractory material being connected to a melting chamber equipped with a separate inductor as a secondary circuit. By attaching an airtight cover to the melting chamber and applying controlled pressure, a controlled appropriate amount of molten metal is poured into molds etc. from the pouring nozzle at the top of the pouring siphon that is integrally formed from the bottom of the melting chamber and rises upwards. Pour hot water into the water. The inductor has enough power to keep it warm, and receives pre-melted molten metal from the receiving chamber at the top of the receiving siphon, which is integrally formed and rises from the bottom of the melting chamber, similar to the pouring nozzle.
For example, Utility Model Publication No. 1986-50860, Utility Model Publication No. 1986-50860,
(See Publication No. 43658).

Next, the latter ironless induction furnace heats and
It dissolves. To pour the molten metal, the crucible may be tilted to pour the molten metal (see, for example, Japanese Utility Model Application Publication No. 19964/1983), or the on-off valve on the outside of the pouring port at the bottom of the crucible may be opened and closed to pour the molten metal (for example, Japanese Unexamined Patent Publication No. 84-46573 No. 5
), or by opening and closing a stopper present in the molten metal inside the pouring port at the bottom of the crucible (for example, the above-mentioned Japanese Patent Laid-Open No. 64-46573, Figure 4, Japanese Utility Model Publication No. 63-21).
(See Japanese Patent Application Laid-Open No. 62-66089).

[Problem to be solved by the invention]

The former groove-type induction furnace in the conventional technology described above has a pressure increase rate, upper limit pressure for pouring, pouring pressure maintenance time,
It has the advantage of ensuring accurate pouring amount and shortening pouring tact by performing pressure control such as pressure return.

However, when there is little molten metal, the so-called pinch effect exceeds the limit and current cannot be applied, and the grooves must be filled with molten metal at startup and operation, making it impossible to fully discharge the metal. It is impossible to start melting from scrap materials, it takes time to pour metal into the melting chamber and build a furnace that integrates the receiving siphon, and the heating part concentrates on the inductor, which shortens the lifespan and makes it removable from the melting chamber. The problem is that they need to be connected and often replaced.

The latter type of crucible-type induction furnace is free from the problem of pinch effect and the need to constantly fill the groove with molten metal, allows melting from waste materials, has a simple crucible furnace shape, and shortens the furnace construction time to 11 hours.
It has the advantage that it is as short as 5 to 1/10 and the life of the heating section is long.

However, the tilting type naturally has the problem that it is difficult to ensure an accurate pouring amount by operating the stopper or on-off valve.

An object of the present invention is to provide an induction melting furnace that eliminates the drawbacks of the groove-type induction furnace and ensures accurate pouring amount.

[Means to solve the problem]

The pressurized pouring type crucible-type coreless induction furnace of this invention 1 houses the crucible-type coreless induction furnace in a container equipped with a removable airtight cover, and controls the pouring pressure of the pouring pressure control device into the container. A pouring pressure pipe to be applied is connected, and a pouring syphon whose lower end opens at the lower part of the crucible and whose upper end is connected to a pouring chamber with a pouring nozzle is passed through the airtight cover, and the lower end opens into the crucible. A hot water receiving siphon with an opening at the bottom and a hot water receiving chamber connected to the upper end is passed through the airtight cover, and the open upper end of the hot water receiving chamber is positioned higher than the molten metal level in the pouring chamber during pouring. be.

The pressurized pouring crucible-type ironless induction furnace of Invention 2 is Invention 1.
A hot water receiving cover that can be opened and closed is airtightly installed at the upper end of the hot water receiving chamber, and a hot metal receiving pressure pipe is provided to apply a pressure lower than the head from the lower end of the hot water receiving siphon to the molten metal surface in the crucible during pouring standby. It is connected to the hot water receiving room.

The pressurized pouring crucible-type coreless induction furnace of invention 3 houses the crucible-type coreless induction furnace in a container equipped with a removable airtight cover, and applies pouring pressure from a pouring pressure control device to the container. A pouring pressure pipe is connected to the pouring pressure pipe, and a pouring syphon whose lower end opens at the lower part of the crucible and whose upper end is connected to a pouring chamber with a pouring nozzle is passed through the airtight cover, and the lower end opens into the upper part of the crucible. A hot water receiving pipe that opens into the space and has a hot water receiving chamber connected to its upper end is passed through the airtight cover, and a hot water receiving cover that can be opened and closed is airtightly provided at the upper end of the hot water receiving chamber.

In addition, invention 3 provides a hot water receiving pipe whose lower end opens in the upper space of the crucible instead of the hot water receiving siphon whose lower end opens at the bottom of the crucible of invention 1, and does not use a hot water receiving pressure pipe in the hot water receiving chamber. It can be said that only an airtight hot water receiving cover is provided.

The pressurized pouring type crucible-type ironless induction furnace of Invention 4 is the invention 2.
Or in invention 3, the molten metal pouring pressure control device is connected to the molten metal receiving pressure pipe instead of the molten metal pouring pressure pipe.

[Effect]

In invention 1, when pressure is applied from the pouring pressure pipe, the molten metal surface so in the crucible falls due to the siphon action, the molten metal rises from the opening at the lower end of the pouring siphon, the molten metal flows into the pouring chamber, and the molten metal surface Maintain S2□. With the head length of 0, the molten metal flows out from the pouring nozzle and is poured into, for example, a mold. When the pressure in the pouring pressure pipe is reduced or returned to atmospheric pressure, the molten metal in the pouring chamber recedes, and the original molten metal surface S0 in the crucible moves down by the amount of poured metal to prepare for the next pouring.

With the above operation, the molten metal rises through the pouring siphon due to the pressure, and at the same time, the molten metal also rises into the molten metal receiving chamber and flows backward, forming a molten metal surface S□ with the same height as S. However, since the open upper end of the molten metal receiving chamber is higher than the molten metal surface S0 of the molten metal pouring chamber (h+ in the figure), the molten metal does not overflow from the molten metal receiving chamber.

If the molten metal in the pot that continues to be poured decreases, you can open the pouring pressure pipe to the atmosphere and replenish the molten metal from the receiving chamber, or open the airtight cover from the container and throw in the waste material. By applying electricity to the windings, it is possible to melt waste materials and keep molten metal warm.

Molten metal moves up and down the receiving siphon by repeated pouring, but the structure is simple as there is no receiving cover.

In invention 2, in addition to the effect of invention 1, the openable and closable melt receiving cover is airtightly closed, and a pressure lower than the head between the molten metal surface S0 in the crucible and the lower end of the melt receiving siphon is applied from the receiving metal pressure pipe. By repeatedly applying pouring pressure and depressurizing from the pouring pressure pipe, the molten metal does not move up and down greatly in the receiving siphon, preventing the molten metal from moving in and out of the receiving chamber, preventing the temperature of the molten metal from dropping. be done. In addition, since the pressure applied from the receiving pressure pipe is as described above, the molten metal surface St in the receiving siphon
Pressurized gas will not enter the crucible as bubbles from the lower end of the crucible. Even if there is some gas leakage due to poor airtightness of the hot water receiving cover, the pouring pressure control will not be affected as long as the gas is allowed to flow to maintain the above pressure.

Invention 3 is similar to the function of Invention 1, and the molten metal is poured through the siphon, the molten chamber, and the molten nozzle by applying pressure from the molten metal pouring pressure pipe, but at this time, the molten metal receiving pipe on the molten metal receiving side is Since its lower end opens into the upper space of the crucible, there is no side effect of molten metal flowing into or out of the receiving pipe or receiving chamber.

However, in Invention 2, even if the airtightness of the hot water receiving cover in the hot water receiving room is slightly deteriorated, the function will not be impaired, but in Invention 3, if the hot water receiving cover is not airtight, pressure may leak, and the hot water cannot be poured. This makes effective pouring pressure control somewhat difficult.

Invention 4, even if the hot water receiving siphon pipe is long and has a siphon effect (Invention 2), or is short and is a simple hot water receiving pipe that opens into the upper space of the crucible and does not have a siphon effect (Invention 3), Instead of pouring molten metal into a pressure pipe, the molten metal is poured by connecting a molten metal pouring pressure control device to the molten metal receiving pressure pipe in the molten metal receiving chamber, which is made airtight with a molten metal receiving cover.

The pouring pressure is applied either by applying gas that is discharged into the crucible from the lower end of the receiving siphon, or by applying it directly to the molten metal surface from the receiving pipe.

〔Example〕

FIG. 1 is a cross-sectional view of an embodiment, in which a crucible-shaped coreless induction furnace 4 consisting of a yoke 1, a winding 2, and a crucible 3 is supported by a base material 5 at the bottom, a support material 6 at the top, etc. It is housed in a cylindrical container 7 with a bottom, and stores molten metal 8.

The container 7 is removably provided with an airtight cover 12 which is positioned with a pin 9, fixed with a screw 10, and made airtight with a gasket 11. The airtight cover 12 is provided with a heat insulating material 3, which is connected to a pouring pressure control device F25 via a pouring pressure pipe 14.
connected to.

The pouring siphon 15 passes through the airtight cover 12 in an airtight manner,
The lower end opens at the bottom of the crucible 3, and the upper end opens into the pouring nozzle 1.
It communicates with a horizontally elongated pouring chamber 17 equipped with 6. The pouring chamber 17 is partially covered with a lid 18 with some gaps to prevent foreign matter from entering and leakage due to flow of the molten metal.

The hot water receiving siphon 19 passes through the airtight cover 12 in an airtight manner,
The lower end opens into the lower part of the crucible 3, and the upper end communicates with the hot water receiving chamber 20. The open upper end of this hot water receiving chamber 20 is the hot water pouring chamber 17.
It is higher than the molten metal surface Stt at the time of pouring. The pouring siphon 15, the receiving siphon 19, the pouring chamber 17, and the receiving chamber 20 are formed using known materials and molding methods suitable for their shapes.

The explanation of the structure up to this point relates to the first invention, and next, the portion related to the second invention will be explained based on the same drawings.

At the upper end of the hot water receiving chamber 20, a hot water receiving cover 23 is provided which can be opened and closed with a hinge 21 and kept airtight with a gasket 22, and a hot water receiving pressure pipe 24 is connected thereto.

A pressure lower than the head between the molten metal surface So in the crucible 3 during pouring standby and the lower end of the molten metal siphon 19 is applied to the molten metal receiving pressure pipe 24 by a pressurizing device (not shown).
The molten metal surface St is maintained to prevent the applied gas from flowing into the crucible 3. Therefore, as the So is lowered by pouring the molten metal, the applied pressure is also lowered accordingly. Since So can be known from the pressure of the molten metal pouring pressure pipe, the appropriate pressure of the molten metal receiving pressure pipe 24 can also be easily known.

Note that even if the applied gas rises from the lower end of the molten metal in the form of bubbles in the crucible, the gas will not generate harmful components to the molten metal, for example, if it is an inert gas, the pouring pressure pipe Pressure may be applied from the molten metal receiving pressure pipe without supplying molten metal pouring pressure from 14. This is invention 4.

To explain the third aspect of the present invention using FIG. 1, the lower end of the hot water receiving siphon 19 opens into the pot upper space shown by the dashed line in the figure, and since there is no siphon action, it should be called a hot water receiving pipe. , can be integrally formed with the refractory material of the hot water receiving chamber 20. Invention 4 applies the pouring pressure from the receiving pressure pipe 24 instead of the pouring pressure pipe 14. At this time, the hot water receiving cover 23 must be airtight enough to withstand frequent opening and closing due to repeated pouring of hot water.

[Effect of the invention] The pressurized pouring type crucible-type coreless induction furnace of this invention group has a crucible-type coreless induction furnace housed in an airtight container to which pouring pressure can be applied, and a pouring chamber equipped with a pouring nozzle. Since the pouring siphon connected to the pot is opened at the bottom of the container and a receiving chamber is provided, all of the molten metal in the pot can be discharged without the troublesome maintenance inherent to inductors. The furnace structure is extremely simple, reducing the time required to rebuild the furnace, and ensuring an accurate amount of molten metal.

Providing an airtight hot water receiving cover in the hot water receiving chamber or applying an appropriate metal receiving pressure will reduce or eliminate the rise and fall of the molten metal on the receiving side each time the metal is poured, thereby preventing the temperature of the molten metal from dropping. be.

Then, by ensuring the airtightness of the hot water receiving cover and using a hot water receiving pipe or hot water receiving siphon, it is possible to pressurize pouring from the hot water receiving side.
This has the effect of further simplifying the overall structure.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the embodiment. 4... Crucible-shaped coreless induction furnace, 7... Container, 12.
...Airtight cover 14...Pouring pressure pipe, 15...Pouring siphon, 17...Pouring room, 19...Hot water receiving siphon, 20...Hot water receiving chamber, 23...Receiving hot water cover

Claims (1)

[Claims] 1) A crucible-shaped coreless induction furnace is housed in a container equipped with a removable airtight cover, and a pouring pressure pipe for applying pouring pressure from a pouring pressure control device is connected to this container. A pouring syphon whose lower end opens at the lower part of the crucible and whose upper end is connected to a pouring chamber with a pouring nozzle is passed through the airtight cover, and whose lower end opens at the lower part of the crucible and connects a pouring chamber to the upper end. A pressurized pouring type crucible characterized in that a receiving siphon connected to the melt receiving chamber is passed through the airtight cover, and the open upper end of the receiving chamber is positioned higher than the molten metal surface of the pouring chamber during pouring. Iron-free induction furnace. 2) In the pressurized pouring type crucible-shaped coreless induction furnace according to claim 1, a hot metal receiving cover that can be opened and closed is airtightly provided at the upper end of the hot metal receiving chamber, and the molten metal surface in the crucible is A crucible-type coreless induction furnace of pressurized pouring type, characterized in that a receiving pressure pipe which applies a pressure lower than the head from the lower end of the receiving siphon is connected to the receiving chamber. 3) The crucible-shaped coreless induction furnace is housed in a container equipped with a removable airtight cover, and a pouring pressure pipe for applying pouring pressure from a pouring pressure control device is connected to this container, so that the lower end is inside the crucible. A pouring siphon having a pouring chamber with a pouring nozzle connected to the crucible and opening at the lower end of the crucible is passed through the airtight cover, and the lower end thereof is open to the upper space of the crucible and the upper end thereof is connected to a pouring chamber. A crucible-type coreless induction furnace of a pressurized pouring type, characterized in that a pipe passes through the airtight cover, and an openable and closable hot water receiving cover is airtightly provided at the upper end of the hot water receiving chamber. 4) In the pressurized molten metal pouring crucible type coreless induction furnace according to claim 2 or 3, the molten metal pouring pressure control device is connected to the molten metal receiving pressure pipe instead of the molten metal pouring pressure pipe. A type of crucible-type coreless induction furnace.