JPH0359389A - Melting of metal - Google Patents

Abstract

PURPOSE:To improve thermal efficiency by a method wherein metallic material, projected outwardly from an opening, is charged into a crucible and fuel is burnt by a burner, then, the opening is closed by a lid after the material is molten and entered into a furnace body while combustion air for the burner is preheated by exhaust gas from a combustion chamber. CONSTITUTION:Material M is charged into a crucible 14 in a condition that the upper part of the material M is projected outwardly from the opening of a lid 20. When gas fuel is burnt by a burner 17 under this condition, the crucible 14 is heated in a combustion chamber 12 and exhaust gas passes from the opening 22 through a preheating tube 24. The exhaust gas in the preheating tube 24 is discharged to the outside from the opening 25 of a preheating lid 26. The material M is molten and the molten material M drops into a furnace body 9, then, the preheating tube 24 and the preheating lid 26 are removed and the opening 22 of the furnace lid 20 is closed by a lid 28. The exhaust gas from an exhaust gas passage 19 is discharged to the outside through the burner 17 and combustion air for the burner 17 is preheated by the exhaust gas whereby the thermal efficiency may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a metal melting method that can be suitably implemented, for example, for melting non-ferrous metals using a crucible furnace.

Conventional technology A typical prior art is shown in FIG.

A burner 3 is provided facing the combustion chamber 2 of the furnace body 1, and an ingot 5, which is a metal material such as copper alloy or aluminum, to be melted is placed in a wrapper 4 provided in the combustion chamber 2. charged. A furnace lid 6 mounted on the upper part of the furnace body 1
has an open lower.

The crucible 4 is placed on the brightener 8.

When melting the ingot 5, the ingot 5 is charged so as to protrude outward from the open lower, and the exhaust gas from the burner 3 is discharged from the combustion chamber 2 through the open lower, and the ingot 5 near the open lower is also melted. The ingot 5 is preheated by the exhaust gas and the heating of the ingot 5 is promoted.

Problems to be Solved by the Invention In such prior art, even after the ingot 5 is heated and the melt falls into the bottom 4, the exhaust gas continues to be discharged through the open lower door, so that the Improvement in thermal efficiency is desired.

An object of the present invention is to provide a metal melting method that improves thermal efficiency.

Means for Solving the Problems In the present invention, a metal material to be melted protruding outward from an opening formed in the upper part of the furnace body is charged into a crucible provided in a combustion chamber of a furnace body, and the metal material to be melted is placed in a crucible provided in a combustion chamber of a furnace body. The fuel is combusted by a burner provided in the combustion chamber, exhaust gas is discharged from the opening, and after the material has melted and entered the furnace body, the opening is closed with a lid,
This metal melting method is characterized by preheating combustion air in a burner using exhaust gas from a combustion chamber.

According to the present invention, a metal material such as a non-ferrous metal ingot is charged into the crucible in a state protruding outward from an opening formed in the upper part of the furnace body, and in this state, fuel is supplied by a burner. Since the exhaust gas obtained by combustion is discharged from the opening, the material near the opening is preheated by this exhaust gas.

After the material has melted and entered the furnace body, the opening is closed with a lid. At this time, the combustion air in the burner is preheated by the exhaust gas in the combustion chamber. Therefore, it is possible to improve thermal efficiency.

Embodiment FIG. 1 is a sectional view showing a state in which a metal material M according to an embodiment of the present invention protrudes outward from an opening 22 to perform preheating. The furnace body 9 of the crucible furnace includes a furnace wall 10 and a hearth 11. A combustion chamber 12 is formed within this furnace body 12 . In the combustion chamber 12, near the center of the hearth 11, a phaser 13 is provided, and a crucible 14 made of a refractory material is placed on top of this enrichment 13.
is placed.

A cylindrical partition member 15 called a muzzle is provided in the furnace body 9 to surround the crucible 14 and form a combustion chamber 12 between the crucible 14 and the crucible 14 . An annular closure body 16 is provided at the top of the crucible 14 and the top of the partition member 15 .

A tip 18 of a burner 17 faces the upper part of the combustion chamber 12, and gas fuel is combusted within the combustion chamber 12. The exhaust gas passes through an exhaust gas passage 19 formed between the partition member 15 and the inner peripheral surface of the furnace body 10, and further through an exhaust gas passage between the furnace M20 provided at the upper part of the furnace body 9 and the closing body 16. 21, the air is discharged from an opening 22 formed in the furnace cover 20, and is led to a burner 17, as will be described later, to be used for preheating combustion air. The opening 22 of the furnace 1220 is formed directly above the crucible 14 .

An outlet 23 is formed on the upper surface of the hearth 11 that smoothly continues and slopes downward as it moves outward in the radial direction. This outlet 23 has a closing member 2 made of glass fiber or the like.
4 is packed and the metal material is melted.

When melting a material M that is an ingot of a non-ferrous metal material, for example, a copper alloy or aluminum, the material M is charged into the crucible 14, and the upper part of the material fIM protrudes outward from the opening 22 of the furnace lid 20. state. A preheating cylinder 24 surrounding the material M is removably mounted on the furnace lid 20, and a preheating lid 26 having an opening 25 is mounted on the preheating cylinder 24. When the gas fuel is combusted by the burner 17 in this state, the Luppo 14 is burned in the combustion chamber 12.
is heated, and the exhaust gas passes through the exhaust gas passage 19.degree. 21 and passes through the opening 22 into the preheating tube 24.

As a result, the material M is preheated within the preheating cylinder 24.

The exhaust gas in the preheating tube 24 is discharged to the outside from the opening 25 of the preheating ff126. The entire amount of the exhaust gas in one exhaust gas passage may be led from the passage 21 through the opening 22 into the preheating cylinder 24, and a part of the exhaust gas may be discharged from the exhaust gas passage 19 through the burner 17. Good too.

After the material M is melted and the melt falls into the furnace body 9, the preheating cylinder 24 and the preheating lid 26 are removed and the opening 22 of the furnace M20 is opened, as shown in FIG. M2S
occluded by At the same time, the exhaust gas from the exhaust gas passage (2) 9 is discharged to the outside via the burner 17, and the combustion air of the burner 17 is preheated by this exhaust gas. In this way, thermal efficiency can be improved.

FIG. 3 is a sectional view showing the structure of an example of the burner 17. The gaseous fuel is pumped through a fuel supply pipe 29 whose axis coincides with the horizontal axis of the burner 17 . Surrounding this fuel supply pipe 29, the first cylinder 30, the second cylinder 31, the third @32, the fourth cylinder 33, and the fifth cylinder are arranged in order from the inside to the outside in the radial direction.
The tubes 34 are arranged in this order. The tip of the second cylinder 31 is
It continues to the tip cylinder 35 facing the combustion chamber 12. An air supply hole 36 through which combustion air is supplied is formed in the first cylinder 3o.

The exhaust gas passage 37 between the second cylinder 31 and the third cylinder 32 is connected to a riser pipe 38 outside the furnace wall 10 . Combustion air is supplied to the pipe line 39, a chamber 41 formed by an outer cylinder 40 surrounding the riser pipe 38, the tip 4 and the fifth cylinder 33, 34.
A chamber 42 formed by the third and fourth cylinders 32.
33 and a chamber 44 formed by the first and second cylinders 31, the fuel is supplied from the supply hole 36 to the tip 18 of the burner 17.

A nozzle 45 is provided in the middle of the riser pipe 38, and air is injected from the nozzle 45 in the direction of an arrow 46, thereby forming an ejector 57. As a result, the exhaust gas passage 1
The exhaust gas of No. 9 is in the room 47 between the second and third cylinders 31 and 32.
The water is sucked through the riser 38.

Air is supplied by the fan 48 at a pressure of, for example, 700 mmAq, and is forced into the room 41 from the flow rate control damper 49, through the pipe line 50, through the damper 51, and from the pipe line 39. The air from the pipe 50 is branched to the damper 5
2 through a conduit 53 to a nozzle 45. The gas fuel passes from the pipe line 54 to the fuel supply pipe 29 via the damper 55.
is pumped to. This gas fuel is, for example, city gas 13
A and its pressure is 200 m rn A q.

Dampers 49.55 operate in conjunction. The cylinder 35 and the first cylinder 30 to the fifth cylinder 34 are made of metal, and the combustion air flowing in the chambers 41 to 44 is preheated by the high temperature exhaust gas flowing in the chamber 47.

As shown in FIG. 1 above, using the preheating tube 24,
When the material f1M protruding from the opening 22 of the furnace N20 is preheated by exhaust gas, the damper 52 is kept closed. As a result, most of the exhaust gas is guided from the exhaust gas passage 19 to the opening 22 via the exhaust gas passage 21, and almost no exhaust gas flows into the chamber 47 of the burner 17.

The material M is melted as described above, and the melt is dropped into the opening 22 of the furnace M20.
In the state shown in FIG. 2 in which the lid 28 is closed, the damper 52
is opened, and the ejector 57 sucks exhaust gas into the burner 17 and discharges it. This exhaust gas is burner 1
Combustion air is preheated by passing through chamber 47 of 7 and through riser 38 .

The present invention is not limited to metal melting furnaces using crucible 14, but can also be practiced in connection with metal melting furnaces having other configurations, with burner 17 being limited to the configuration shown in FIG. Other burners may also be used.

Effects of the Invention As described above, according to the present invention, when the metal material is charged into the crucible with the opening formed in the upper part of the furnace body protruding outward, the opening allows the exhaust gas to be discharged and the The material is preheated, and after the material has melted, the opening is closed with a lid and the exhaust gas inside the combustion chamber is used to preheat the combustion air of the burner, so thermal efficiency can be improved. It becomes possible.

[Brief explanation of drawings]

FIG. 1 shows a state in which a metal material M according to an embodiment of the present invention protrudes outward from an opening 22 to perform preheating! A cross-sectional view showing the
Fig. 2 is a sectional view showing a state where the material M has melted and the opening 22 is closed with M2S, Fig. 3 is a sectional view showing the structure of an example of the burner 17, and Fig. 4 is a sectional view of the prior art. .

Claims (1)

[Claims] A metal material to be melted protruding outward from an opening formed in the upper part of the furnace body is charged into a crucible provided in the combustion chamber of the furnace body, and in this state, the crucible is placed in the combustion chamber. Burning fuel with a provided burner and exhausting exhaust gas from the opening, and after the material has melted and entered the furnace body, closing the opening with a lid,
A metal melting method characterized in that combustion air in a burner is preheated by exhaust gas from a combustion chamber.