JPS6226483A - Atmosphere circulation type furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a circulating atmosphere furnace, and in particular to a heat treatment furnace for glass products.

(Prior art and its problems) Conventionally, as an atmosphere circulation type furnace, for example, the type disclosed in Japanese Patent Publication No. 58-34416 has been widely adopted.

That is, as shown in FIG. 6, a partition plate (matsufuru) 2 is installed inside the furnace l to form an atmosphere circulation path 3 between it and the furnace wall, and a circulation fan 4 installed on the furnace ceiling circulates the atmosphere inside the furnace. After circulating and raising the temperature with a heating means 5 such as a parser,
The heat is blown upward from the bottom of the furnace to heat-treat the processing material (not shown) placed on a conveyor belt 6 made of a mesh belt. Note that 7 is a support plate made of a perforated plate.

By the way, in order to uniformly heat treat the material on the conveyor belt, it is necessary to ensure that the circulating atmosphere is sufficiently mixed to have a uniform temperature, that the circulating atmosphere is evenly in contact with the processing material, and that the partition plate 2. It is necessary that no drift occurs in the flow.

However, in the conventional method, the circulating atmosphere in the furnace is supplied from the lower part of the atmosphere circulation path 3 located on both sides to the lower part of the conveyor belt 6, and from the conveyor belt 6 to the partition plate 2.
Since the treated material is blown out inward, some parts of the treated material are in contact with the atmosphere and others are not in contact with the atmosphere, and furthermore, the material is not blown out uniformly in the oven width direction and the oven length direction. Furthermore, since there is no mixing means in the atmosphere circulation path 4, the atmosphere heated by the heating means 5 such as a burner does not mix sufficiently with other atmospheres. Moreover, a temperature difference of ±15° C. occurred in the furnace atmosphere in the furnace length direction, making it extremely difficult to uniformly heat treat the treated material. This means that
The same applies to the gradual cooling zone and the cooling zone.

The present invention has a simple configuration, forms a circulating atmosphere with a uniform temperature, makes the circulating atmosphere inside the partition plate uniformly contact the material to be treated, and furthermore makes the circulating atmosphere uniform in the oven width direction and the oven length direction. An object of the present invention is to provide an atmosphere circulation furnace capable of uniformly heat-treating materials by blowing air.

(Means to Solve the Problems) In order to achieve the above object, the present invention provides an atmosphere circulation system having a circulation fan in the furnace ceiling and an atmosphere circulation path formed by a partition plate provided in the furnace. In the furnace, upper and lower perforated plates are arranged in the upper part of the partition plate, and a partition plate extending in the furnace length direction is provided in the space formed between the perforated plates, so that the space is separated from the furnace. The chamber is divided in the width direction, and the circulation fan blows the atmosphere inside the furnace from the atmosphere circulation path downward through the perforated plate.

(Example) Next, the present invention will be explained according to the drawings which are one example.

As shown in FIG. 4, the atmosphere circulation furnace T to which the present invention is applied has a heating/soaking zone 10. Gradual cooling zone 26 and cooling zone 2
9, the processing material is conveyed through each zone by a conveyor belt 6, and is heat-treated during that time.

Note that each of the bands includes a plurality of unit bands 10A, 26A,
It consists of 29A.

The unit zone 10A of the heating/soaking zone 10 is approximately the first
As shown in the figure, the furnace body 11 is made of a refractory heat insulating material 12, and is comprised of a partition plate (matsufuru) 13 provided inside the furnace, a circulation fan 17, and a burner 19 as a heating means. This burner 19
may be a radiant tube or an electric heater.

The partition plate I3 has side plates 14 on both sides and a bottom ceiling 15 on the top surface. 3 is suspended and fixed from the furnace ceiling. Further, spaces are provided between the side plate 14 and the furnace bottom and between the furnace side wall, while the blades 18 of the circulation fan 17 attached to the furnace ceiling are located at the ceiling 15, The space forms an in-furnace atmosphere circulation path (hereinafter referred to as circulation path) 16.

Furthermore, a burner 19 is located in this circulation path 16.

In the present invention, two perforated plates 20a and 20b are arranged in upper and lower stages at a predetermined interval above the partition plate 13,
A space 23 is formed between these perforated plates 20a and 20b, and the space 23 is divided into four sections 25a to 25d in the oven width direction by three partition plates 24a, 24b, and 24c extending in the oven length direction. It is divided into

The diameters of the holes 21 provided in the upper perforated plate 20a are larger in the central part (in the embodiment, the two central sections 25b and 25c) than the diameters of the holes 21 on both sides. The diameters of the holes 22 in the porous plate 20b are all uniform and smaller than the diameter of the holes 2I in the perforated plate 20a. Also,
Circulation) Ann 17 is designed to blow out the atmosphere inside the furnace downward.

Next, as shown in FIG. 2, the unit zone 26A of the slow cooling zone 26 has a configuration of the unit zone of the heating/soaking zone IO + OA, as well as a cooling duct 2 that introduces the atmosphere above the partition plate 13.
7 and an exhaust duct 28 for discharging the atmosphere inside the furnace.
Air intake amount from cooling duct 27 and exhaust duct 28
The exhaust fireflies in the furnace atmosphere are adjusted to maintain a predetermined temperature.

Further, the unit zone 29A of the cooling zone 29 has the configuration shown in FIG.
The only difference is that it does not have an insulating structure.

Next, the operation of the atmosphere circulation furnace constructed as described above will be described.

First, in the heating/soaking zone 10, when the burner 19 is burned and the circulation fan 17 is rotated, the atmosphere in the furnace is circulated through the circulation path 16 as shown by the arrow, and is heated by the burner 19 to a predetermined temperature. The atmosphere inside the furnace is suctioned and stirred by the circulation fan 17 and blown out into the partition plate +3.

By the way, due to the characteristics of the circulation fan 17, the atmosphere inside the furnace blown out from the circulation fan 17 is blown diagonally downward in large quantities due to centrifugal force, as shown in FIG.

However, in the present invention, there are two perforated plates in upper and lower stages.
0a, 20b are arranged, and the upper perforated plate 2'
Since the diameter of the hole 21 provided in Oa is large in the central part, not only does each compartment space 25a to 25d receive a fairly uniform amount of air, but even if each compartment space 2
Even if the furnace atmosphere enters 5a to 25d in the diagonally downward direction i, it will not move to other compartment spaces, but will be blown out straight and uniformly downward from the small diameter holes in the lower stage.

This means that slow cooling zone 26. The same applies to the cooling zone 29, and the heat treatment method is the same as that of the conventional method, so a detailed explanation will be omitted.

In the above description, the hole diameters of the upper perforated plate 20a are made different between the central portion and both side portions, but they may all have the same hole diameter and the number of holes may be increased in the central portion.

(Effects of the Invention) As is clear from the above description, according to the present invention, the circulating atmosphere in the furnace heated by the heating means is not directly supplied into the partition plate from the conveyor belt section, but instead Circulation fan installed on the ceiling.

After being stirred and mixed for several minutes, it enters a compartment space formed by perforated plates provided in two stages, upper and lower, and partitioned in the width direction of the furnace.
Since the air is blown downward from here, it is possible to provide a uniform amount of atmosphere to the treated material in a circulating atmosphere with a uniform temperature distribution.Furthermore, the amount of air blown from the perforated plate is uniform in the furnace width direction and furnace length direction. This allows the treated material to be heat-treated almost uniformly.

Therefore, even if the treated material has poor thermal conductivity, such as a glass product, it will not be damaged due to thermal distortion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the heating/soaking zone, FIG. 2 is a sectional view of the slow cooling zone, FIG. 3 is a sectional view of the cooling zone, and FIG. 4 is a schematic plan view of the atmosphere circulation furnace of the present invention. FIG. 5 is an explanatory diagram showing the state of the air volume of the circulation fan, and FIG. 6 is a sectional view of a conventional atmosphere circulation type furnace. 1O ~ heating/soaking area, 11 ~ furnace body, 12 ~ resistance Wk
+−k l Q, 1ffi[I c, s+mp
Missing +7=2111; ring fan, 20a, 20b-
Perforated plate, 21.22 one hole, 23~space, 24~partition plate,
26~ slow cooling zone, 27~ cooling duct, 28~ exhaust duct,
29 ~ Cooling zone. Patent applicant Chugai Roko Kogyo Co., Ltd. Agent Patent attorney Aoyama Sho and 2 others @ 1 Figure 5 FIJ Figure 6 Procedural amendment [Mutsu] July 2, 1985

Claims (3)

[Claims] (1) In an atmosphere circulation furnace that has a circulation fan on the furnace ceiling and an atmosphere circulation path formed by a partition plate installed in the furnace, two perforated plates, upper and lower, are installed in the upper part of the partition plate. A partition plate extending in the length direction of the furnace is provided in the space formed between the perforated plates to partition the space in the width direction of the furnace. An atmosphere circulation type furnace characterized in that the internal atmosphere is ejected downward through a perforated plate. (2) The space has at least three spaces in the center and on both sides.
The atmosphere circulation type furnace according to claim 1, characterized in that the furnace is divided into chambers. (3) The atmosphere circulation furnace according to claim 1 or 2, wherein the hole diameter at the center of the upper perforated plate is larger than the hole diameter at both sides.