JPH022077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for promoting heat transfer from hot air to an object to be heated in a heating furnace such as a ceramic furnace or a metal heating furnace.

BACKGROUND ART In order to promote heat transfer from the hot air to the heated object in a heating furnace, it has been proposed to blow hot air onto the heated object. However, since heat is transferred from the hot air to the heated object by convection heat transfer, the effect cannot be obtained unless the hot air is blown at a considerable speed, for example, 70 m/sec or more. Therefore, this method requires a huge amount of blower power and is not profitable, so it is rarely practiced these days.

In addition, a radiant is placed in the heating furnace, and the object to be heated is heated by convection heat transfer by hot air, and the radiator is also heated, and the object to be heated is heated by the radiant heat from the heated radiator, increasing the heat transfer efficiency. It has also been conventionally done to raise the temperature. In methods of heating objects using radiant heat from a radiant that absorbs heat from hot air, a porous radiator is often provided at the flue outlet in order to effectively recover waste heat. . However, in the past, the gas flow inside the furnace was not sufficiently considered, which resulted in temperature unevenness in the porous radiator, leading to early deterioration of the radiator and damage to the heated object due to uneven heating of the object. There's a problem.

An object of the present invention is to eliminate the drawbacks of the prior art as described above and to provide a heating furnace in which heat transfer from hot air to an object to be heated is promoted.

The heating furnace according to the present invention is a heating furnace that heats with hot air, and has an inner ceiling with high ventilation, heat resistance, and radiation ability above the object to be heated, and one or more inner ceilings on the furnace wall above the inner ceiling. One or more hot air outlets are provided on the furnace wall under the inner ceiling facing the object to be heated, and the heated air outlets and the hot air outlet are connected via a blower. , a heating furnace characterized in that the hot air below the middle ceiling is heated, moves to the top of the middle ceiling, and is further blown toward the object to be heated through a hot air outlet and a hot air outlet. It is.

In a preferred embodiment of the heating furnace according to the present invention, the inside of the heating furnace is divided into a plurality of sections in the flow direction of the hot air, and one or more hot air outlets and one hot air outlet in the section are divided into a plurality of sections in the direction of flow of hot air. A blower connection is provided and preferably a barrier is provided between the compartments.

In another preferred embodiment of the heating furnace according to the present invention, all of the hot air outlets and all of the hot air outlets are connected by one blower.

EMBODIMENT OF THE INVENTION Hereinafter, the heating furnace of this invention is demonstrated based on the drawing of an Example. 1 and 2 show a schematic configuration of a heating furnace of the present invention, with FIG. 1 being a longitudinal sectional view and FIG. 2 being a sectional view taken along the line -- in FIG. 1.

In the drawings, 1 is the ceiling wall of the heating furnace, and 2 is the side wall. A rail 3 is laid at the bottom of the hearth, and the rail 3
A trolley 4 on which a heated object 5 is mounted is moved from right to left in FIG. The hot air is introduced from the left in FIG. 1, heats the object to be heated 5, and is discharged from the flue 6. The above is no different from a conventional heating furnace.

In this heating furnace, a medium ceiling 7 is provided above the area through which the object to be heated 5 passes, maintaining an appropriate distance from the object to be heated 5 and the ceiling wall 1, and having a large air permeability, heat resistance, and radiation ability.
is provided. The mid-ceiling 7 needs to have low ventilation resistance when hot air passes through the mid-ceiling 7, and also needs to have high heat resistance to withstand high hot air temperatures. Furthermore, since it is provided to give the heat absorbed from the hot air as radiant heat to the object to be heated, it needs to be a material with high radiant power, that is, high blackness. In addition, in order to increase the heat transferred from the hot air (mostly convection transferred heat), increasing the speed of the hot air that contacts the inner ceiling 7 increases ventilation resistance, which increases the capacity of the blower described later. This is not a good idea because it has to be It is desirable to increase the surface area of the inner ceiling 7 in order to increase convective heat transfer from hot air. Preferable materials for the inner ceiling 7 include ceramics and heat-resistant metals. Preferred forms of the interior ceiling 7 include honeycomb shapes, net shapes, intertwined fiber shapes, and lattice brick shapes. In addition, the installation method is either by hanging it with an appropriate hanging means or by stacking it up.

A plurality of hot air outlet ports 8 are provided in the upper side wall 2 of the middle ceiling 7, and hot air outlet ports 9 are provided in the lower side wall 2 of the middle ceiling 7 toward the object to be heated 5. The hot air outlet 8 and the hot air outlet 9 are connected via a blower 10. For the combination of the hot air outlet 8 and the blower outlet 9, the inside of the heating furnace is divided into a plurality of sections in the flow direction of the hot air, and the hot air outlet 8 and the blower outlet 9 in each section are combined into one blower 10. It is connected with In the illustrated embodiment, it is divided into four sections. The boundaries of each section are indicated by dashed lines 11. In this embodiment, each compartment includes one hot air outlet 8 and one blower outlet 9 on both sides. Therefore, for each section,
Moreover, one hot air outlet 8 and one blower outlet 9 are connected to one blower 10 on each side. When each compartment includes a plurality of outlets 8 and 9, manifolds are installed on both sides of the suction and discharge ports of one blower in each compartment. Connect. In addition, all the hot air outlets 8 and all the hot air outlets 9 can be connected to one unit without dividing the inside of the heating furnace.
A manifold may be used to connect the individual blowers. In some embodiments, only one outlet 8 and one outlet 9 are connected to one blower 10. In the illustrated embodiment, the hot air outlet 8 and the hot air outlet 9 are provided on the furnace wall 2 on both sides of the heating furnace, and are connected to the blower 10 separately. may be connected to the same blower 10, or the outlet 8 and the outlet 9 may be provided only on one side. However, in order to uniformly heat the inner ceiling 7, to heat the heated object 5 uniformly and efficiently, to avoid complicating hot air piping, and to reduce pressure loss, there are outlet ports 8 on both sides as shown in the figure. It is desirable to provide the outlet 9 and the blower 10 separately.

When the inside of the heating furnace is divided into a plurality of sections in the flow direction of the hot air and a partition wall is provided at the boundary position 11 of each section, the hot air can be circulated more efficiently.

This heating furnace is constructed as described above. When the blower 10 is operated, hot air is sucked through the outlet 8 and hot air is blown out from the outlet 9 toward the object to be heated 5 . Since the operation of the blower 10 causes a pressure difference between the upper and lower portions of the inner ceiling 7, the hot air below the inner ceiling 7 passes through the gap in the inner ceiling 7 and moves upward. Medium ceiling 7
is heated during this time and acts as a radiant and radiates radiant heat toward the object to be heated 5.

The hot air blown from the air outlet 9 to the object to be heated 5 gives heat to the inner ceiling 7 and its temperature is slightly lowered, and the blowing speed is not set very high. However, the object to be heated 5 is heated by the radiant heat from the inner ceiling 7, and furthermore, due to the hot air blown out from the air outlet 9, a relatively high-temperature hot gas flow approaches the object to be heated under the inner ceiling 7. is stirred and the convection transfer rate increases, so the object to be heated is efficiently heated.

As described above, in the heating furnace of the present invention, the object to be heated can be efficiently heated. In addition, since the radiator in the middle ceiling is heated evenly due to the stirring of the hot gas flow by the blown hot air, there is no risk of early deterioration or uneven heating of the object to be heated. Furthermore, since hot air blowing does not need to be carried out at high speed as in the past, a significant increase in power costs can be prevented.

[Brief explanation of drawings]

1 and 2 are longitudinal sectional views showing a schematic configuration of an embodiment of the heating furnace of the present invention, and -
FIG. 1...Ceiling wall, 2...Side wall, 3...Rail, 4
... Trolley, 5 ... Heated object, 6 ... Flue, 7 ...
Middle ceiling, 8...Hot air outlet, 9...Hot air outlet,
10...Blower, 11...Boundary line of compartment.

Claims (1)

[Scope of Claims] 1. In a heating furnace that heats with hot air, an inner ceiling with high ventilation, heat resistance, and radiation is provided above the object to be heated, and one or more inner ceilings are provided on the furnace wall above the inner ceiling. One or more hot air outlets are provided in the furnace wall below the inner ceiling toward the object to be heated, and the hot air outlet and the hot air outlet are connected via a blower, A heating furnace characterized in that the hot air below the middle ceiling is heated and moved to the top of the middle ceiling, and is further blown toward the object to be heated through a hot air outlet and a hot air outlet. 2. The heating furnace is divided into a plurality of sections in the direction of hot air flow, and one or more hot air outlet and hot air outlet in each section are connected by one blower. Heating furnace in scope 1. 3. The heating furnace according to claim 2, wherein a barrier is provided between compartments in the heating furnace. 4. The heating furnace according to claim 1, wherein all of the hot air outlets and all of the hot air outlets are connected by one blower.