JPH03150312A - Fluidized bed heating furnace - Google Patents

Abstract

PURPOSE:To allow the easy and rapid maintenance and inspection of a gas diffusion plate by supplying a fluidizing gas via the gas diffusion plate to fluidize the fluid particles packed thereon and holding this gas diffusion plate on the outside of the furnace. CONSTITUTION:The gas diffusion plate 2 is disposed in the lower part in a furnace vessel 1 provided with a heat insulating member 5 on the outside and the fluid particles 4A are packed into the fluidizing space 4' in the upper part thereof. The fluidizing gas G supplied into a supply space 3 packed with spherical bodies 11 below the above-mentioned gas diffusion plate 2 is passed in the fluidizing space 4' via this gas diffusion plate 2 to fluidize the fluid particles 4A. The fluidizing gas G is heated to a prescribed temp. by a heating element 6 to heat treat the material which is to be treated and is disposed in the fluidized bed 4. The gas diffusion plate 2 of the above mentioned fluidized bed heating furnace is inserted via a holding member 10 into the bottom of the furnace vessel 1. Further, the juncture between the flange plate 10b of the holding member 10 and the flange 1a of the furnace vessel 1 is provided on the outside of the furnace bottom, by which the gas diffusion plate 2 is easily attachably and detachably mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a fluidized bed heating furnace used for heat treatment of metal objects and the like.

(Prior art) As shown in FIG. 2, a fluidized bed heating furnace has a supply space 3 at the bottom of a furnace vessel l and a gas distribution plate 2 made of porous material or the like. A fluidized space 4'' (formed by the upper surface of the gas distribution plate 2 and the furnace vessel l) is filled with fluidized particles 4A such as alumina particles, and the inside of the adiabatic furnace body 5 covering the outer periphery of the furnace vessel l is filled with fluidized particles 4A such as alumina particles. A heating element 6 is provided, and a gas supply pipe 7 is provided.
By supplying the fluidizing gas G to the supply space 3 through the gas dispersion plate 2 and blowing the fluidized gas into the fluidized bed 4, - the fluidized particles 4A are heated or cooled while floating and stirred, and the fluidized particles 4A are heated or cooled while being suspended and stirred; The workpiece W immersed in the layer 4 is subjected to a heat treatment such as quenching or a surface treatment such as carburizing or nitriding by mixing the required gas with the fluidizing gas G.
Compared to an atmospheric furnace, this method has advantages such as a good heat transfer coefficient due to the fluidized particles, a uniform temperature distribution, and the ability to shorten processing time.

In such a fluidized bed heating furnace, the gas dispersion plate 2 is generally made of metal (for medium temperatures up to 1100°C), and in this case, it is often of a welded structure integrated with the metal furnace vessel l. It is used. However, if you want to perform heat treatment at a higher temperature, it is necessary to use a non-metallic refractory such as ceramics for the gas distribution plate 2, and even for medium temperature use, a non-metallic refractory may be used. In this case, maintenance is required due to the possibility of damage, so the structure must be such that the gas distribution plate 2 can be separated from the furnace vessel 1.

Therefore, in the past, the furnace vessel 1 was separated into the furnace upper part 1A and the furnace bottom part IB, and the distribution plate holding plate 8 was fixed to the outer periphery of the gas distribution plate 2.
A and a flange 1b at the bottom of the furnace, and is removably attached with bolts.

(Problems to be Solved by the Invention) The conventional separation structure as described above has the following problems.

(i) Since the connecting part between the gas separation plate 2 and the furnace vessel 1 is inside the furnace body, it is not easy to remove and reinstall the gas separation plate;
It took a long time to maintain and inspect the gas separation plate.

(ij) Since the connection part is close to the heating element 6, the flange l
The a, lb, and seals 9 were heated to high temperatures, causing gas leakage due to deterioration, causing problems in reliability and lifespan. For this reason, it was difficult to raise the temperature of the fluidized bed heating furnace (up to 1300°C).

This invention was made to solve the above-mentioned problems, and its purpose is to enable easy and quick maintenance and inspection of the gas distribution plate, and to improve the connection between the furnace vessel and the gas distribution plate. The object of the present invention is to provide a fluidized bed heating furnace that eliminates overheating, improves reliability, extends life, and allows production of a high-temperature fluidized bed heating furnace.

<Means for Solving the Problems> In the present invention, a gas distribution plate 2 is installed at the bottom of a furnace vessel l, and a fluidized particle 4A is filled in a fluidized space 4'' on this gas separation plate 2 to disperse gas. In a fluidized bed heating furnace in which fluidizing gas G is supplied to the fluidized particles 4A through the plate 2, and the gas distribution plate 2 is removably attached to the furnace vessel 1, the gas distribution plate 2 is connected through the holding member lO. The holding member 10 is inserted into the bottom of the furnace vessel 1, and the connection portion between the holding member 1O and the furnace vessel 1 is placed outside the furnace at the bottom of the furnace.

<Function> Since the connection part between the gas distribution plate 2 and the furnace vessel l is outside the furnace,
The gas distribution plate 2 can be taken out and reinstalled easily and quickly.

The flange and seal 9 at the connection portion can be placed outside the furnace away from the heating element, thereby eliminating overheating of the flange and seal 9 and lowering the temperature.

(Embodiment) The present invention will be described below based on an illustrated embodiment.The same reference numerals are given to parts that are the same as or correspond to the conventional ones.

As shown in FIG. 1, the furnace vessel l is a cylindrical vessel with an open bottom, and a flange 1a that projects laterally is integrally provided at the lower end of the furnace vessel that projects outside the furnace at the bottom of the furnace. The gas distribution plate 2 is made of a porous nonmetallic refractory such as ceramics, and is inserted into the bottom of the furnace vessel l via the holding member 10.

This holding member 10 is composed of a dispersion plate holding tube 10a having a diameter smaller than the inner diameter of the furnace vessel 1, and a flange plate 10b that can close the lower opening of the furnace vessel l. Fix it in the same position as before,
A supply space 3 is formed below. The flange plate ab has a supply hole 10c in the center for supplying fluidizing gas G,
The outer periphery is attached to the flange 1a via the seal 9 and fastened with bolts.

In addition, in the supply space 3, there is a spherical body 1 made of alumina or the like.
The main purpose of this spherical body 11 is to disperse the fluidizing gas G introduced from the gas supply pipe 7 and supply it to the gas distribution plate 2. It also acts as a heat insulator to prevent heat transfer to the flange plate fob.

In the above configuration, when performing maintenance,
By removing the bolts, the flange plate 10b is attached to the flange l.
a and then pull out the gas separation plate 2 together with the holding member 10 out of the furnace. .

Note that although the present invention is extremely effective when applied to high temperature (~1300°C) fluidized bed heating furnaces, it is applicable to medium temperature (~1100°C)
Needless to say, it can also be applied to

<Effects of the Invention> As described above, in the fluidized bed heating furnace according to the present invention, the gas separation plate is inserted into the bottom of the furnace vessel through the holding member, and the holding member and the furnace vessel are connected to the outside of the furnace at the bottom of the furnace. Since the connection is made with , the following effects are achieved.

(i) Since the connecting portion between the gas separation plate and the furnace vessel is located outside the furnace, the gas separation plate can be easily and quickly removed and reinstalled, and maintenance, inspection, etc. can be performed in a short time.

(ii) Since the connection part is located outside the furnace, away from the heating element, overheating of the flange and seal of the connection part can be eliminated;
It can improve reliability and extend life. Furthermore, by lowering the temperature of the connection part, the temperature inside the bed can be increased, and the high temperature fluidized bed heating furnace (
~1300''C) is possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a fluidized bed heating furnace according to the present invention, and FIG. 2 is a longitudinal sectional view showing a conventional fluidized bed heating furnace. ■...furnace vessel, la...flange, 2.
... Gas distribution plate, 3 ... Supply space 4 ... Fluidized bed, 4" ... Fluidization space 4A ... Fluidized particles, 5 ... Adiabatic furnace body 6 ... Heating element
7... Gas supply pipe, 8... Dispersion plate holding plate 9.
... Seal, IO... Holding member, 10a...
・Dispersion plate holding tube, 10 b--flange plate, 11
--・Spheroidal body 1st figure 2 instrument 2nd figure 1r--

Claims (1)

[Claims] (1) A gas distribution plate is installed at the bottom of the furnace vessel, fluidized particles are filled in the fluidized space above the gas distribution plate, and fluidizing gas is supplied to the fluidized particles through the gas distribution plate. , in a fluidized bed heating furnace in which the gas distribution plate is removably attached to the furnace vessel, the gas distribution plate is inserted into the bottom of the furnace vessel via a holding member, and the holding member and the furnace vessel are connected. A fluidized bed heating furnace characterized in that a portion of the furnace is located outside the furnace at the bottom of the furnace.