JP2847543B2 - Atmosphere heat treatment furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a plurality of substantially horizontally connected heat treatments such as firing and oxidation of electronic components, light alloys, chemical conversion raw materials, and the like in a required atmosphere. The present invention relates to an atmosphere heat treatment furnace in which a furnace core tube serves as a heat treatment chamber to which an atmosphere gas is supplied.

[Prior art] Conventionally, this type of atmosphere heat treatment furnace has been designed so that when the atmosphere gas is harmful to a heater disposed outside the processing chamber, the heater is directly connected to the atmosphere gas leaking from a joint (joint) of the furnace core tube. In order to prevent exposure, the furnace core tube is doubled, and the leak gas is exhausted to the outside of the furnace without flowing into the heater chamber.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional atmospheric heat treatment furnace, since the heater is arranged outside the double furnace core tube, the heat transfer efficiency becomes extremely poor, and the heat treatment chamber is maintained at a required temperature. Therefore, the surface temperature of the heater rises more than necessary, and the load increases. Therefore, depending on the temperature of the heat treatment, there is a problem that there is no suitable heater material or the life is significantly shortened.

Therefore, an object of the present invention is to provide an atmosphere heat treatment furnace that can increase heat transfer efficiency and extend the life of a heater.

[Means for Solving the Problems] In order to solve the above problems, an atmosphere heat treatment furnace according to the present invention is an atmosphere heat treatment furnace which serves as a heat treatment chamber in which an atmosphere gas is supplied inside a plurality of furnace core tubes connected substantially horizontally. A space is formed between the heat treatment chamber and the refractory heat-insulating layer coaxially surrounding the heat treatment chamber, and this space is air-tightly divided at the middle part and the end part of each of the furnace core tubes to join the heater chamber. The joint chamber is provided with an exhaust port.

[Operation] In the above-described means, the furnace core tube becomes single, and gas leaked from the joint does not flow into the heater chamber.

In the joint chamber, it is desirable to provide not only an exhaust port but also an air supply port, to supply a forming gas from the air supply port, to draw out the gas together with the atmospheric gas leaked from the joint from the exhaust port to the outside of the furnace, and burn it.

In addition, it is preferable to provide an air supply port in the heater chamber to supply air at a slightly higher pressure than the joint chamber. In this way, the inflow of gas from the joint chamber is prevented twice. And the life thereof can be further extended.

Embodiment An embodiment of the present invention will be described below with reference to FIG. 1 showing the concept of an atmosphere firing furnace.

In the drawing, reference numeral 1 denotes a tunnel-shaped firing chamber, which is formed in a plurality of relatively short furnace core tubes 2 made of an alumina refractory and arranged substantially horizontally. At one end of the firing chamber 1 (the left end in FIG. 1), there is a loading chamber 3 for loading the firing target.
The loading chamber 3 is provided with an atmosphere gas supply port 4 for supplying an atmosphere gas such as NH ₃ gas to the firing chamber 1. On the other hand, on the other end side of the firing chamber 1, an unloading chamber 5 for unloading the fired product is connected, and the unloading chamber 5 is provided with an atmosphere gas exhaust port 6 for discharging an atmosphere gas. The atmosphere gas exhausted from the atmosphere gas exhaust port 6 is fired using a pilot burner 7 using LPG or the like.

A cylindrical airtight space is formed on the outer periphery of the firing chamber 1 by coaxially surrounding the firing chamber 1 with a refractory heat insulating layer 9 attached to the inside of a jacket 8 such as a steel plate.
A heater chamber 11 and a joint chamber 12 are provided by hermetically separating an intermediate portion and an end portion of each furnace core tube 2 by a ring-shaped partition wall 10. Each heater chamber 11 houses a heater (not shown) such as a SiC heating element,
As will be described later, an air supply port 13 for supplying air or the like at a pressure slightly higher than the pressure of the forming gas supplied to the joint chamber 12 or at atmospheric pressure in the heater chamber 11 is provided below the heater chamber 11. On the other hand, in each joint chamber 12, a forming gas supply port 14 for supplying a forming gas such as N ₂ gas into each joint chamber 12 is provided at a lower portion thereof, and leaks from the joint 2a of the furnace core tube 2. A forming gas exhaust port 15 for discharging the forming gas together with the atmospheric gas is provided at an upper portion thereof. The forming gas and the atmosphere gas exhausted from the forming gas exhaust port 15 are fired in the same manner as the atmosphere gas exhausted from the atmosphere gas exhaust port 6 described above.

When the atmosphere baking furnace having the above configuration was operated, no abnormality was particularly found in the heater, and the heater could be used for the same period as when used in a normal atmosphere (air).

On the other hand, in the furnace shown in FIG.
Otherwise, when operating the furnace under the same conditions, compared to the furnace of the example, about
The heater was broken during the period of 1/5 and became unusable.

[Effects of the Invention] As described above, according to the present invention, the furnace core tube becomes single,
In addition, since the gas leaked from the joint does not flow into the heater chamber, the heat transfer efficiency can be significantly increased as compared with the related art, and the service life of the heater can be made substantially equal to the use in the atmosphere.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an atmosphere firing furnace showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Firing chamber, 2 ... Furnace core tube 2a ... Joint, 4 ... Atmospheric gas supply port 6 ... Atmospheric gas exhaust port, 9 ... Refractory insulation layer 10 ... Partition wall, 11 ... Heater chamber 12 …… Joint chamber 14 …… Forming gas supply port 15 …… Forming gas exhaust port

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Hirao 1 Minamifuji, Ogakie-cho, Kariya-shi, Aichi Pref. Toshiba Ceramics Co., Ltd. Kariya Works (56) References −31009 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F27D 7/00-7/06 F27B 17/00 C21D 1/74

Claims (1)

(57) [Claims] An atmosphere heat treatment furnace in which a plurality of furnace tubes arranged substantially horizontally is a heat treatment chamber to which an atmosphere gas is supplied, wherein a space is provided between the heat treatment chamber and a refractory heat-insulating layer coaxially surrounding the heat treatment chamber. On the other hand, this space is air-tightly partitioned between the middle part and the end part of each furnace core tube to provide a heater chamber and a joint chamber, and an exhaust port is provided in the joint chamber. Atmosphere heat treatment furnace.