JPH08157978A - Reaction type aluminum holding furnace - Google Patents

Abstract

PURPOSE: To provide a small-sized and compact gas combustion type aluminum melting furnace. CONSTITUTION: A luminous flame type burner 3 is installed downward through the ceiling of a combustion chamber 2 of a box type installed in the opening on the upper surface of an aluminum melting chamber 1 and having opened lower surface. A heat exchanger 6 which consists of a metallic pipe 5 closed at its front end and is divided internally into a forward path and backward path and a flanged main body part 6 holding this metallic pipe 5 in the state of inserting the pipe into a discharge hole 4 and has combustion air inlet and outlet ports 7, 8 communicating with the forward and backward paths described above and a discharge duct connecting port 9 communicating with a discharge hole 4 bored in the side wall of the combustion chamber 2 is mounted at the outer end of this discharge hole 4. As a result, the preheating of the combustion air is executed within the thickness of the side wall of the combustion chamber consisting of refractories and, therefore, a gas reflection type having a large heating up capacity is realized at a low cost even in an aluminum holding furnace of such a relatively small size that the installation space for the heat exchanger for preheating is not secured. atop the combustion chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type aluminum holding furnace using a gas burner.

[0002]

2. Description of the Related Art An aluminum holding furnace is installed at a casting site,
The molten aluminum is poured and held in a molten state. Generally, as a small aluminum holding furnace, an electric reverberatory furnace that uses an electric heater is often used, and a gas reverberatory furnace that heats metal by radiation of a gas flame and reflection from a wall surface is often used in a melting furnace. Although it is
It was not used in aluminum die castings and aluminum holding furnaces in aluminum foundries where it was necessary to secure a working space because the gas burner equipment took up space.

[0003]

However, the electric reverberatory furnace requires no piping or heat exchanger as compared with the gas reverberatory furnace and the heating device is compact, but the running cost is higher than that of city gas. In addition, there are drawbacks in that expensive power receiving equipment is required and the temperature raising capability is lower than that of the gas reverberation furnace. On the other hand, the biggest difficulty in adopting a gas reverberation furnace as an aluminum holding furnace is that there is a large demand for a furnace with a relatively small processing capacity, so there is a space to install a heat exchanger for air preheating together with a burner on the upper surface of the furnace. It was difficult to secure. An object of the present invention is to solve the above-mentioned problems and to provide a gas reflex furnace suitable for an aluminum holding furnace having a relatively small capacity.

[0004]

As shown in FIG. 1, a reflection type aluminum holding furnace according to the present invention is installed on the upper opening of an aluminum melting tank 1 and on the ceiling of a box-shaped combustion chamber 2 whose lower surface is opened. The metal tube 5 having the bright flame burner 3 penetrating downward and the end closed at the outer end of the exhaust hole 4 formed in the side wall of the combustion chamber 2 and the inside divided into a forward path 5a and a return path 5b. And a flange-shaped main body portion 6 for holding the metal pipe 5 in the exhaust hole 4 in a state of being retained therein, and the main body portion 6 has combustion air inlets and outlets 7 and 8 communicating with the reciprocating path, and the exhaust hole. A heat exchanger 6 having an exhaust duct connecting port 9 communicating with 4 is attached to preheat the combustion air for the burner 3 by the exhaust gas discharged from the combustion chamber 4.

[0005]

The fuel is mixed with the combustion air preheated by the heat exchanger 5a, forms a luminous flame in the combustion chamber 2 and burns, and the exhaust gas generated as a result is exhausted on the side wall of the combustion chamber 2. The low-temperature combustion air, which is discharged through the hole 4, passes through the metal tube 5 through the wall of the metal tube 5 of the plug-in heat exchanger 6 inserted into the exhaust hole 4 at this time, Heat exchange takes place with the hot exhaust gas on the outside, preheating the combustion air. In this way, since the combustion air is preheated within the thickness of the side wall of the combustion chamber 2 made of a refractory material, a relatively small size where the installation space for the preheating heat exchanger cannot be secured on the upper surface of the combustion chamber. It has become possible to use a gas combustion type with low cost for the reflection type aluminum holding furnace.

[0006]

1 and 2 show an embodiment of a reflection type aluminum holding furnace according to the present invention, in which an aluminum melting tank 1 and a combustion chamber 2 installed at an opening of the upper surface thereof are refractory materials. The flame burning burner 3 is mounted downward on the ceiling of the box-shaped combustion chamber 2 having an open bottom surface. In FIG. 1, 11 is a lid for the aluminum inlet and 12 is a lid for the aluminum outlet. Further, a cylindrical exhaust hole 4 is bored in the side wall of the combustion chamber 2, and an outer end of the exhaust hole 4 is composed of a metal tube 5 and a flange-shaped main body portion 6 as shown in FIG. The heat exchanger 6 for preheating air is mounted with the metal tube 5 inserted in the exhaust hole 4.

FIG. 3 shows the structure of the heat exchanger. The inside of the metal tube 5 whose front end is closed and whose base end is connected to the main body 6 is divided into a forward path 5a and a reverse path 5b by a partition plate 10. On the other hand, the main body 6 is provided with combustion air inlets / outlets 7 and 8 communicating with the reciprocating paths 5a and 5b, and an exhaust duct connecting port 9 communicating with the exhaust hole 4, and a high temperature generated from the burner 3 is formed. When the exhaust gas is exhausted to the outside through the space between the inner wall surface of the exhaust hole 4 and the metal pipe 5, the combustion air supplied to the burner 3 through the metal pipe 5 is heated to remove the exhaust heat. Is recovered. Exhaust gas is exhausted to the outside by an ejector (not shown) connected to the exhaust duct. It is necessary to control the eject air amount that drives this ejector and the combustion air supply amount in conjunction with each other. This prevents the pressure inside the furnace from fluctuating.

FIG. 4 shows a schematic structure of the bright flame burner 3, in which a fuel gas supply cylinder 15 is arranged in an outer cylinder 14 and swirl vanes 16 are provided between both cylinders. The primary air supplied to the outer cylinder 14 makes a spiral motion by the swirl vanes 16 while passing between the fuel gas supply cylinder 15 and the outer cylinder 14, and the empty space surrounded by the outer cylinder 14 in front of the fuel gas supply cylinder 15 A spiral is formed in the space of the fuel mixing chamber A. Fuel gas is gas supply cylinder 1
5 is supplied to the central portion of this spiral and is entrained in the swirling motion of the primary air and mixed with the primary air. However, since the velocity component of these gases in the cylinder axis direction is smaller than the velocity component of the swirling motion, And the fuel gas are sufficiently mixed by the time they come out from the tube end of the outer tube 14. If the supply amount of the primary air is set to be smaller than that required for complete combustion of the fuel gas, the fuel gas generates soot due to incomplete combustion during the above-described swirling motion, and the soot is removed from the cylinder end of the outer cylinder 15. Since the secondary air is completely burned by being surrounded by the outside air, a bright flame B having high radiation efficiency is formed at the cylinder end of the outer cylinder 14, and the bright flame B is caused by the swirling motion in the cylinder axis direction. Since the flow velocity of is low, the flame length becomes short and the surface becomes flat. It should be noted that since soot is collected at the tip of the fuel supply cylinder 15 where the swirling velocity is low, an air supply pipe 17 is further provided in the fuel gas supply cylinder 15, and the tip of the air supply pipe 17 is projected from the tip of the gas supply cylinder 15. The air supply hole 17 is provided on the peripheral side surface of the tip of the air supply cylinder 17 to blow away the soot pool to prevent the burner 3 from being soiled with soot.

[0009]

As described above, according to the present invention, the luminous flame burner 3 is mounted downward on the ceiling of the upper combustion chamber 2 of the aluminum melting furnace, and the exhaust hole 4 is formed in the side wall of the combustion chamber 2. A plug-in type heat exchanger 6 is inserted to preheat low temperature combustion air passing through the metal pipe 5 with high temperature exhaust gas outside, and combustion is performed within the thickness of the side wall of the combustion chamber made of refractory material. Since the air is preheated, even in a relatively small reflective aluminum holding furnace where it is not possible to secure a space for installing the preheating heat exchanger on the upper surface of the combustion chamber, a gas with a high heating capacity at a low cost can be obtained. There is an advantage that a combustion type can be realized.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is a lateral cross-sectional view of the main part of the above.

FIG. 3 is a cross-sectional view of a heat exchanger used in the present invention.

FIG. 4 is a schematic sectional view of a burner used in the present invention.

[Explanation of symbols]

 1 Aluminum Melting Tank 2 Combustion Chamber 3 Bright Flame Burner 4 Exhaust Hole 5 Metal Pipe 5a Outgoing 5b Return 6 Heat Exchanger or Main Body 7 Combustion Air Inlet 8 Combustion Air Outlet 9 Exhaust Duct Connection Port

Claims (1)

[Claims] 1. A flame-extinguishing burner is installed in an upper opening of an aluminum melting tank and has a lower opening in the ceiling of a box-shaped combustion chamber, and an exhaust hole is formed in a side wall of the combustion chamber. At the outer end of the metal tube, the tip of which is closed and the inside of which is divided into a forward path and a return path, and a flange-shaped main body portion which holds the metal pipe in the exhaust hole. A heat exchanger having a combustion air inlet / outlet communicating with the reciprocating path and an exhaust duct connecting port communicating with the exhaust hole is mounted, and the combustion air for the burner is preheated by the exhaust gas discharged from the combustion chamber. Reflective aluminum holding furnace characterized by doing so.