JPH06281350A - Hot blast circulating type furnace - Google Patents

Abstract

PURPOSE:To execute a high temperature heating of a treatment article by decreasing heat loss accompanying an operation of a hot blast circulating type furnace heating the treatment article by blasting hot blast in the furnace, and by improving a fire-resisting performance of a circulating fan and the like. CONSTITUTION:In a hot blast circulating type furnace blowing out, into the furnace, gases sucked from an inner portion of the furnace by driving a circulation fan 4, a suction flow path and a blowout flow path of the circulation fan 4 are respectively divided into at least two systems, heaters 11a and 11b and the like are set on blowout openings 9a and 9b in the furnace, of respective blowout flow paths 8a and 8b, and at crossing points of suction paths 6a and 6b and the blowout paths 8a and 8b, respectively heat storing bodies 10a and 10b are arranged freely to exchange a path so that they exist in the suction paths 6a and 6b or the blowout paths 8a and 8b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot air circulation type furnace capable of heating a processed product to a high temperature by blowing hot air into the furnace, and more particularly to reducing heat loss accompanying its operation. It is intended to improve the durability of a circulating fan or the like.

[0002]

2. Description of the Related Art Conventionally, hot air capable of rapidly heating a processed product in a furnace to a high temperature by driving a circulating fan to heat gas sucked from the furnace by a heater or the like and blowing the heated gas to the processed product in the furnace as hot air. Circulating furnaces are known. However, this type of hot-air circulation type furnace has a problem with the heat resistance of the circulation fan and consumes a large amount of heat energy because the gas sucked from the furnace was once cooled and then heated by a heater or the like on the downstream side of the circulation fan. Therefore, the running cost is generally very high. Further, a heat exchanger is conventionally provided in the flue of the furnace to recover the heat energy discharged together with the exhaust gas, and the heat energy is effectively used to heat the primary air of the burner to save energy. Are also known to try to achieve.

[0003]

However, since it is not easy to recover the heat energy by the heat exchanger in the above hot air circulation type furnace, the heat energy loss is great especially in a furnace that blows out hot air at a high temperature of about 1200 ° C. At the same time, there is a problem that the circulation fan cannot withstand such a high temperature.

[0004]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above problems, and in a hot air circulation type furnace in which a circulating fan is driven to blow gas sucked from the inside of the furnace into the circulating fan, At least two suction channels and two outlet channels
A heating source such as a heater is provided at the outlet in the furnace of each of the outlet flow passages, and a heat storage body is provided at the intersection of the inlet passage and the outlet passage in the inlet passage or the outlet passage. It is characterized in that the flow path can be switched so as to intervene.

[0005]

By interposing both heat storage bodies alternately in the suction flow passage and the blowout flow passage, the heat storage body in the suction flow furnace is heated by the gas sucked from the furnace, and the flow paths are switched. The heated heat storage body comes to intervene in the blowout flow path, and the gas blown into the furnace can be heated. For this reason, the thermal energy is temporarily stored in the heat storage body, which reduces the waste of the thermal energy to the outside and enables effective use, and the temperature of the gas sucked by the circulation fan through the suction passage decreases and the circulation fan decreases. The durability of.

[0006]

EXAMPLES Next, one example of the hot air circulation type furnace according to the present invention will be described with respect to a floating furnace of a strip-shaped metal material. FIG. 1 is a cross-sectional view of this hot air circulation type furnace, in which 1 is a furnace body surrounded by heat insulating walls, 2 is a plenum chamber provided in the bottom of the furnace body 1, and 3 is an upper surface of the plenum chamber 2. It is a strip-shaped metal material that is floated and supported by the hot air blown from and is conveyed in the furnace.

Reference numeral 4 denotes a circulation fan which is rotationally driven by a motor 5. The suction side of the circulation fan 4 is branched into two systems of a suction passage 6a and a suction passage 6b, and the suction passage 6a is provided in the furnace body 1.
Of the furnace body 1 and the suction passage 6b can be communicated with the suction port 7a of the furnace body 1 which is open to the other side wall. The outlet side of the circulation fan 4 is branched into two systems of an outlet passage 8a and an outlet passage 8b, and the outlet passage 8a is formed on one side of the plenum chamber 2 provided in the furnace body 1. Blow-out flow path 8 communicating with the outlet 9a
b is an outlet 9b formed on the other side of the plenum chamber 2
To communicate with. Reference numerals 11a and 11b are heaters provided at the air outlets 9a and 9b as heating sources.

A heat storage element 10a is provided at the intersection of the suction passage 6a and the outlet passage 8a so that the passage can be switched. A reference numeral 10b is provided at the intersection of the suction passage 6a and the outlet passage 8b so that the passage can be switched. It is a heat storage body. The heat storage body 10a and the heat storage body 10b are configured by filling a heat storage material having a large heat capacity, such as a ceramics ball, and a high heat resistance in a form of a cylinder having open both ends so as to maintain air permeability. The heat storage body 10a and the heat storage body 10b are respectively sucked by the suction flow passage 6a by rotating both ends of the cylindrical body by 90 degrees so as to match the openings on both ends with the suction flow passage 6a, the suction flow passage 6b or the blowing flow passage 8a, the blowing flow passage 8b. The switching operation can be performed so as to intervene in the inside, the suction flow path 6b, the blowout flow path 8a, and the blowout flow path 8b.

In the hot-air circulation type furnace configured as described above, as shown in FIG. 1, the heat storage body 10a is set to be interposed in the suction flow passage 6a, and the heat storage body 10b is placed in the blowout flow passage 8a. When the circulation fan 4 is driven to rotate by energizing only one heater 11b, the gas in the furnace body 1 is sucked through the suction port 7a and flows through the heat storage body 10a, so that the heat storage body 10a Is heated to a high temperature by the gas in the furnace, and the gas whose temperature has been lowered is sucked by the circulation fan 4 through the suction passage 6a. Then, this gas passes through the blow-out passage 8b and flows through the heat storage body 10b to absorb the heat of the heat storage body 10b to raise the temperature, and is further heated by the heater 11b to become hot air of high temperature, and the air outlet 9b. Further blown into the plenum chamber 2, the strip-shaped metal material 3 is floated by the hot air blown from the plenum chamber 2 and heated to a high temperature.

In this way, when the heat storage body 10a can be heated to a high temperature by the gas in the furnace by operating for several seconds to several pickup seconds, the switching operation is performed as shown in FIG. 2 and the heat storage body 10a is interposed in the blowout passage 8a. Then, the heat storage body 10b is moved to the suction flow path 6
The heater 11a is energized and the heater 11b is stopped by interposing it in b. In this operation mode, the gas in the furnace body 1 is sucked through the suction port 7b and flows through the heat storage body 10b, so that the heat storage body 10b is heated to a high temperature by the heat of the furnace gas, and the temperature of the gas is lowered. Is sucked by the circulation fan 4 through the suction flow path 6b. The gas blown out from the circulation fan 4 has a heat storage body 10a heated to a high temperature in the previous process.
The heat of the heat storage body 10a is absorbed by raising the temperature of the heat storage body 10a, and further heated by the heater 11a to a high temperature and blown into the plenum chamber 2 to heat the strip-shaped metal material 3 to a desired high temperature. In this way, the flow paths are switched so that the heat storage bodies 10a and 10b alternately repeat heat storage and heat radiation. When the temperature of the hot air blown into the furnace is high, the circulation fan is preferably made of an oxide-dispersed sintered superalloy in which fine powder of high-melting oxide such as yttria is dispersedly contained. Of course, when the temperature of the hot air blown into the furnace is low, it goes without saying that the circulation fan can function even if it is formed of a heat resistant material such as heat resistant steel.

[0011]

As described above, in the hot air circulation type furnace of the present invention, the temperature inside the furnace gas is lowered by passing through the heat storage body so that the gas is sucked into the circulation fan. Is never hit directly. Therefore, even if the gas temperature in the furnace is set to be considerably high according to the purpose of processing, it is possible to avoid a situation in which the operation is hindered due to overheating of the circulation fan. Further, since the heat of the gas in the furnace is temporarily stored in the heat storage body, it can be used without waste, so that the heat energy can be effectively used and the running cost can be suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hot air circulation type furnace showing an embodiment of the present invention.

FIG. 2 is an operation state diagram of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 furnace body 4 circulation fan 6a, 6b suction flow path 7a, 7b suction port 8a, 8b blowout flow path 9a, 9b blowout port 10a, 10b heat storage body 11a, 11b heater

Claims (1)

[Claims] 1. A hot-air circulation type furnace in which a circulation fan is driven to blow gas sucked from the inside of the furnace into the furnace, and the suction passage and the outlet passage of the circulation fan are branched into at least two systems, respectively. A heating source is provided at the outlet in the furnace of each outlet passage, and the passages can be switched so that a heat storage medium is interposed in the inlet passage or the outlet passage at the intersection of the inlet passage and the outlet passage. A hot air circulation type furnace characterized by being arranged in