JP3338145B2 - Nonferrous metal melting and holding furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonferrous metal melting and holding furnace.

[0002]

2. Description of the Related Art In a conventional melting and holding furnace, the entire side and bottom of the furnace body are made of refractory material, and a single burner is provided in a lower part of the crucible in the furnace. The structure is such that combustion gas is discharged from the upper part while turning around a part of the crucible.

[0003]

In a conventional melting and holding furnace, the entire side surface of the furnace body is made of a refractory material, and it takes a long time for the furnace to reach a predetermined temperature and operate. Needed, once stopped, considerable loss time occurs, which limits energy savings.

[0004] Since the burner heats a local portion of the lower portion of the crucible, the local portion of the crucible is oxidized, the local portion is subjected to a temperature shock, the life of the crucible is short, and the difference between the upper and lower temperatures of the molten metal in the crucible is large.

[0005] Since the furnace body is integrally formed, it takes time and effort to manufacture, and when it is damaged, it must be completely replaced or repaired.

According to the present invention, the furnace body can be divided and assembled into a plurality of parts, thereby facilitating manufacture, repair and partial replacement. Without heating, the whole or most of the outer peripheral surface of the crucible is heated to prolong the life of the crucible,
An object of the present invention is to reduce a vertical temperature difference of a molten metal in a crucible.

[0007]

SUMMARY OF THE INVENTION In a non-ferrous metal melting and holding furnace comprising a cylindrical furnace provided with a crucible, a furnace body can be divided and assembled into a plurality of stages vertically and a means for heating the crucible is provided. It is preferable that the bottom part of the furnace body is a crucible receiving part, the middle part is a heating part provided with a heating means, and the upper part is an upper edge part of the furnace body. The upper edge portion of the upper furnace body can be further divided into a plurality of stages and combined so as to be overlapped and divided.

[0008] In the furnace body, a ring-shaped lid that is open at the center and that is in close contact with the upper surface of the upper edge of the furnace body and the opening edge of the crucible is detachably provided. An opening is provided in the section, and an exhaust gas cylinder is attached to the opening.

A ring-shaped lid having an open central portion may be detachably provided on the upper surface of the upper edge of the furnace body, and a gap may be provided between the inner surface of the ring-shaped lid and the upper edge of the crucible.

As a heating means, a metal fiber having high heat resistance is compacted into a mat shape, and a burner (referred to as a surface burning burner) for burning a mixture of air and fuel on the surface thereof, or a plurality of heat storage bodies having a heat storage body. By switching the burner, a burner including a burner (referred to as a regenerative combustion burner) for recovering the calorific value of the combustion exhaust gas or a heating means using an electric resistance heating element is used.

[0011]

The furnace body can be divided into a plurality of parts vertically. When all or a part of each stage of the furnace body is made of a lightweight refractory, the heat storage amount of the furnace body is reduced, and the heating rise is accelerated. Surface burners heat all or most of the periphery of the crucible as a surface. The regenerative combustion burner effectively uses exhaust gas by switching a plurality of burners. The heating means using the electric resistance heating element does not generate gas and facilitates handling.

[0012]

An embodiment of the present invention will be described with reference to the drawings. A base 3 comprising a cylindrical side peripheral portion 1 and a bottom plate 2 and having an upper opening is used as a crucible receiving portion and is made of a refractory.

A cylindrical body 4 made of a lightweight refractory such as ceramic fiber or hard aluminum lightweight brick and a mixed gas room 5 along the inner surface of the cylindrical body 4 are made of a metal formed by compacting high heat-resistant metal fibers into a mat shape. A surface combustion burner 8 provided with a mat 6 and provided with a mixed gas supply port 7 opening to a mixed gas room 5 in a cylindrical body 4 is used as a heating unit, and is placed on the side peripheral portion 1 via a sealing material 9. . The sealing material 9 seals the side peripheral portion 1 and the surface combustion burner 8 and absorbs their expansion. Surface burner 8
Is that the mixed gas supplied from the mixed gas supply port 7 to the mixed gas room 5 is injected into the inside of the furnace from a number of small holes of the metal mat 6 and ignited by an igniter (not shown). Burns on surfaces.

An upper furnace body 13 made of a ring-shaped refractory having a through hole is placed on the upper part of the surface combustion burner 8 via a sealing material 12, and the upper furnace body 13 is connected to an upper edge of the furnace body. And detachably fixed using a locking member. The upper furnace body 13 is preferably formed of a lightweight refractory material.

Above the bottom plate 2 of the base 3, a space 10 surrounded by the side peripheral portion 1, the surface combustion burner 8, and the upper furnace body 13 is formed. An exhaust gas cylinder 11 that opens into a space 10 is provided in the side peripheral portion 1. The exhaust gas cylinder 11 is formed of a lightweight refractory or a metal or other material.

The outer periphery of the cylinder 4 and the exhaust gas cylinder 11 made of a lightweight refractory is covered with a metal plate 14. It is preferable that the metal plate 14 also covers the side periphery 1 of the base 3 and the periphery of the bottom plate.

A base 15 is provided on the upper surface of the bottom plate 2, and a crucible 16 is placed thereon. The upper edge of the crucible 16 and the upper furnace body 13 have the same height, and an inner surface abuts on the upper edges thereof, and a lid 18 that seals the space 10 with a sealing material 17 is provided.
Adjustment of a subtle difference in the height of the upper edge of the crucible 16 and the upper furnace body 13 can be performed by the sealing material 17.

The lid 18 is opened above the crucible 16 for charging molten material and sucking out molten metal.

When this melting and holding furnace is used, a molten material is introduced through an opening of the lid 18 and the surface combustion burner 8 is ignited by an ignition device (not shown). The whole or most of the outer peripheral side surface of the crucible 16 is heated to melt the molten material in the crucible 16. At this time, the exhaust gas in the space 10 is discharged to the outside from the exhaust gas cylinder 11. The required molten metal is sucked out from the upper opening of the lid 18.
This furnace can also be used as a holding furnace by injecting molten metal from another melting furnace.

Instead of the above-described embodiment, as shown in FIG.
A gap 19 may be provided between the upper edge of the cover 18 and the lower surface of the lid 18.

In the embodiment shown in FIG.
6 through the gap 19 while heating the upper side surface of the
Is discharged upward from the opening. At that time, the exhaust gas directly exchanges heat with the molten material above the crucible before being put into the crucible 16, thereby saving energy.

In the embodiment of FIGS. 1 and 2, a cylindrical intermediate furnace body made of a refractory, in which one or a plurality of ordinary burners are attached to the lower part of the crucible 16, without using the surface combustion burner 8, is used. Alternatively, the upper furnace body 13 may be mounted on the intermediate furnace body via the seal material 12 with the seal member 9 interposed therebetween, and the three parts may be detachably fixed. In this case, the combustion method is the same as in the conventional case, but the furnace body can be manufactured by dividing it into three parts, and replacement and repair of damaged parts need only be divided and only the corresponding parts are processed.

The heating means is not limited to being provided in the intermediate furnace body, but may be provided in any step or a plurality of steps. As the heating means, an electric resistance heating element can be used. Further, as the heating means, a normal burner or a regenerative combustion burner can be used in addition to the above-described surface combustion burner.

In the surface combustion burner 8, it is preferable that the mixing ratio of air and fuel is larger than the stoichiometric ratio. For example, by setting the air ratio to 1.3, NO
The amount of x generated is about 10 ppm, which can be suppressed to about one fifth to one tenth of the conventional value.

Depending on the temperature, the upper furnace body 13 may be divided and combined into a plurality of stages to change the heat-resistant temperature.

[0026]

[Effect] Since the furnace body is divided into a plurality of stages and assembled, the production is easy, the production time is shortened, and in case of damage, only the corresponding stage can be removed and repaired or replaced. The repair time can be shortened and the repair cost can be reduced.

When a surface combustion burner is used, the surface of the crucible is uniformly heated as a surface surrounding the outer periphery of the crucible, so that the life of the crucible can be maintained for a long time without local heating unlike a conventional furnace. There is no difference between the upper and lower temperatures of the molten metal. Also, a large combustion chamber is not required as compared with the use of a conventional normal burner. Further, since the cylindrical body of the surface combustion burner is formed of a lightweight refractory material, the heat storage amount is small, and it is possible to start up and operate in a short time. When a heating means using an electric resistance heating element is used, exhaust gas is not generated, and it is clean and easy to handle.

Since the structure is simple and the handling is easy, a skilled worker is not required for work such as maintenance of the furnace body, so that ordinary workers at the site can work.

[Brief description of the drawings]

FIG. 1 is a sectional view of a melting and holding furnace according to the present invention.

FIG. 2 is a sectional view of a melting and holding furnace according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Side peripheral part 2 Bottom plate 3 Base 4 Cylindrical body 5 Mixed gas room 6 Metal mat 7 Mixed gas supply port 8 Surface combustion burner 9 Seal material 10 Space 11 Exhaust gas cylinder 12 Seal material 13 Upper furnace body 14 Metal plate 15 Crucible 16 17 sealing material 18 lid 19 gap

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hideo Yoshikawa 1-8-11 Fujigaoka, Midori-ku, Yokohama-shi, Kanagawa 109 NIC Heim Fujigaoka 109 (56) References JP-A-6-48743 (JP, A) Japanese Utility Model Application −19898 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F27B 14/08 F27B 14/14

Claims (4)

(57) [Claims] 1. A cylindrical furnace provided with a crucible, wherein a bottom portion is a crucible receiving portion, a middle portion is a heating portion provided with heating means, and an upper portion is an upper edge portion of the furnace body, and these three portions are combined so as to be overlapped and divided. Non-ferrous metal melting and holding furnace. 2. A further divided into a plurality of stages the upper edge of the upper furnace body superimposed combination dividable characterized by comprising 請
Non-ferrous metal melting and holding furnace according to Motomeko 1. 3. A furnace is provided with a ring-shaped lid which is open at the center and which is in close contact with the upper edge of the upper edge of the furnace body and the opening edge of the crucible. 3. An exhaust gas cylinder attached to an opening of the exhaust gas cylinder according to claim 1.
Non-ferrous metal melting and holding furnace described in any of the above. 4. A ring-shaped lid having an open central portion is detachably provided on the upper surface of the upper edge of the furnace body, and a gap is provided between the inner surface of the ring-shaped lid and the upper edge of the crucible. Claim 1
Non-ferrous metal melting and holding furnace according to one of the other two.