JP5483272B2 - Continuous heat treatment furnace - Google Patents

Description

  The present invention relates to a continuous heat treatment furnace having a muffle.

  Conventionally, a continuous heat treatment furnace having a muffle has been used for firing electronic components. As shown in FIG. 3, the continuous heat treatment furnace F includes, for example, a tunnel-like heat-resistant metal muffle 1 having a flat bottom, and an upper heater 2 and a lower heater for heating the muffle 1 above and below the muffle 1. 3 is arranged, a heat insulating material 6 is arranged so as to surround the heaters 2, 3, and a heater block B composed of the heaters 2, 3 and the heat insulating material 6 is fixed to the furnace and supports the muffle 1. Has been.

  A gas injection nozzle 4 for introducing atmospheric gas into the furnace is fixed to the lower part of the muffle 1, and a gas exhaust nozzle 5 for exhausting atmospheric gas in the direction of the arrow in the muffle 1 to the upper part of the muffle 1. Is fixed. In addition, a conveyor belt 7 (a drive mechanism for the conveyor belt 7 is omitted) that moves in the muffle 1 is disposed for firing electronic components.

  For the firing of processed products such as electronic parts, the processed products placed on the conveyor belt 7 are transported from the inlet 1a of the furnace into the muffle 1 and baked in the muffle 1, and then discharged from the outlet 1b as a baked product. However, in the operation of the conventional continuous heat treatment furnace, there are the following problems.

  That is, when the muffle 1 is heated by the upper heater 2 and the lower heater 3 of the heater block B, the muffle 1 expands and extends in the arrow A direction of the inlet 1a. In this case, the heater block B only supports the muffle 1 and does not move because it is separate from the muffle 1, but the gas injection nozzle 4 and the gas exhaust nozzle 5 fixed to the muffle 1 are The muffle 1 moves in the direction of arrow A at the entrance 1a as the muffle 1 expands and extends.

  FIG. 4 shows a state when the muffle 1 is stretched by thermal expansion after heating in the continuous heat treatment furnace. In anticipation of such movement of the gas injection nozzle 4 and gas exhaust nozzle 5, in the conventional furnace, a gap D corresponding to the movement distance of the gas injection nozzle 4 and gas exhaust nozzle 5 is provided in the heater block B in advance. ing. For this reason, a heater cannot be disposed in the gap D portion, and the gap D needs to be about 50 to 300 mm. Therefore, in the gap D portion, the temperature of the muffle is reduced by about 30 to 80 ° C. In the muffle, a constant temperature cannot be maintained, which affects the quality of the fired product.

Although not directly related to the present invention, the support member (heater block B in the present invention) that supports and supports the muffle is expanded and stretched in the direction of the inlet 1a due to friction. In order to prevent this, it is also proposed to arrange a rotating roll or a rotating sphere on the upper surface of the member so that the muffle can move smoothly even when the muffle extends, and to prevent damage to the support member ( Patent Document 1).
Japanese Patent Laid-Open No. 10-281649

  The present invention was made to solve the above-mentioned conventional problems in a continuous heat treatment furnace having a muffle, and the purpose thereof is to reduce the temperature in the muffle even if the muffle expands and extends during operation of the furnace. Therefore, it is an object of the present invention to provide a continuous heat treatment furnace configured so that the inside of the muffle can be maintained at a constant temperature and the quality of a stable fired product can be maintained.

In order to achieve the above object, a continuous heat treatment furnace according to claim 1 is provided with a muffle, an atmosphere gas injection nozzle for forming an atmosphere in the furnace is fixed to a lower portion of the muffle, and an exhaust for exhausting the atmosphere gas. A nozzle is fixed to the upper part of the muffle, and a heater block is composed of a heater arranged around the muffle and a heat insulating material arranged to surround the heater, and is processed from the furnace inlet to the outlet through the muffle. A continuous heat treatment furnace for firing an electronic component provided with a conveyor belt for conveying a product, wherein the heater block is divided into a plurality of units in the longitudinal direction of the furnace to constitute a plurality of units, and each unit Is fixed to the muffle so that it can move with the muffle as the muffle expands due to thermal expansion. Are more disposed to be fixed to a support member for supporting the muffle, the support member is characterized by being configured to be moved together with the muffle and the heater block in accordance with the stretching by muffle thermal expansion.

  The continuous heat treatment furnace according to claim 2 is characterized in that, in claim 1, the length of each unit is substantially the same, and the length of each unit is substantially the same as the arrangement interval of the support members.

  The continuous heat treatment furnace according to claim 3 is characterized in that, in claim 1 or 2, the support member is provided with a caster.

  According to the present invention, the heater block that surrounds the muffle and is fixed to the muffle is divided in the longitudinal direction of the furnace and is configured to include a plurality of units. Therefore, each unit of the heater block is stretched by thermal expansion of the muffle. Along with this, the gas injection nozzle and the gas exhaust nozzle fixed to the muffle move together, so that almost no gap is generated. Since the length of each unit of the heater block is substantially the same and the unit length is substantially the same as the interval between the support members, the difference in thermal expansion coefficient between each unit and the support member becomes the same. The gaps generated between the units can be made substantially the same. Since the gap generated between the heater blocks is generated in proportion to the length of the unit, the length of the unit is preferably about 2 m. Each unit of the heater block also extends due to thermal expansion, but since the extension length is small compared to the interval between the support members supporting the muffle, a gap is generated between each unit, but the size is set to 20 mm or less. be able to. If the length of the unit is shortened, the equipment cost becomes high, and if the length of the unit is lengthened, the gap between the units becomes large.

  Since there is no gap between the gas injection nozzle 4 and the gas exhaust nozzle 5 and the heater block, the portion where the heater cannot be arranged can be eliminated, and the gap generated between each unit of the heater block can be suppressed to 20 mm or less. There is no temperature drop in the muffle, the muffle can be maintained at a constant temperature, and stable quality of the fired product can be maintained.

  Moreover, since the support member of the muffle has casters and moves on the receiving rail, the support member fixed to the muffle due to thermal expansion can be smoothly moved, so that damage to the member due to the movement is avoided. be able to. By adopting a method such as placing the support member on a sphere, a contact resistance may be reduced and the support member may be moved smoothly.

  Hereinafter, the continuous heat treatment furnace of the present invention will be described with reference to FIGS. 1-2, the same code | symbol was attached | subjected about the same member as the past. As shown in FIG. 1, a continuous heat treatment furnace F according to the present invention includes a muffle 1 as in the prior art, and an upper heater 2 and a lower heater 3 for heating the muffle 1 are disposed above and below the muffle 1, respectively. The heat insulating material 6 is arrange | positioned so that 2 and 3 may be bent.

  The feature of the present invention is that the heater block B composed of the heaters 2 and 3 and the heat insulating material 6 is divided into a plurality of units B1, B2, B3, B4 and B5 are configured, and each unit is fixed to the muffle 1, and is configured to move together with the movement of the muffle 1 by expansion and extension of the muffle 1.

  Further, a plurality of muffles 1 are arranged in the length direction of the muffle and fixed to a support member 8 that supports the muffle 1, and the support member 8 includes a plurality of muffles 1 and heater blocks B that are formed by stretching due to thermal expansion of the muffle. It is the point which can move now with unit B1, B2, B3, B4, B5.

  A more preferable configuration is that the lengths of the units B1, B2, B3, B4, and B5 are substantially the same, and the length of each unit is substantially the same as the arrangement interval of the support members 8. Further, the support member 8 has casters 9 and can move on the rail 10.

  A gas injection nozzle 4 for introducing atmospheric gas into the furnace is fixed to the lower part of the muffle 1, and a gas exhaust nozzle 5 for exhausting atmospheric gas in the direction of the arrow in the muffle 1 to the upper part of the muffle 1. Is fixed, and a conveyor belt 7 (the drive mechanism of the conveyor belt 7 is omitted) is provided to move in the muffle 1 for firing electronic components.

  In the firing of the product to be fired, the product to be fired placed on the conveyor belt 7 is transported from the furnace inlet 1a into the muffle 1 and fired in the muffle 1 as before, and then fired from the outlet 1b as the fired product. It is unloaded and sent to the next process.

  In the continuous heat treatment furnace of the present invention, as described above, the heater block B surrounding the muffle 1 and fixed to the muffle 1 is divided into a plurality of units in the longitudinal direction of the furnace, and a plurality of units B1, B2, B3, B4 are provided. Since the heater block B moves together with the expansion of the muffle 1 due to the thermal expansion of the muffle 1, the movement distance of the gas input nozzle 4 and the gas exhaust nozzle 5 fixed to the muffle 1 is as follows. The gap d of the heater block B hardly occurs, and there is no portion where the conventional heater cannot be arranged. Therefore, the temperature of the muffle does not decrease and the inside of the muffle can be kept at a constant temperature.

  Further, by making the lengths of the units B1, B2, B3, B4, and B5 substantially the same, the thermal expansion amount of each unit becomes the same, and the length of each unit is made substantially the same as the arrangement interval of the support members 8. As a result, the difference in thermal expansion between each unit and the support member becomes the same, so that the gap generated between each unit of the heater block can be made substantially the same. Since the gap generated between the units of the heater block is suppressed to 20 mm or less, there is no temperature drop in the muffle, the muffle can be kept at a constant temperature, and stable quality of the fired product can be maintained. It becomes possible.

  In addition, since the support member 8 includes the caster 9 and the support rail 10 on which the caster 9 can rotate, the support member fixed to the muffle associated with the thermal expansion can be smoothly moved. The damage of the accompanying member etc. can be avoided.

It is a figure which shows the principal part cross section of the longitudinal direction of the continuous heat processing furnace (before a heating) of this invention. It is a figure which shows the principal part cross section of the longitudinal direction of the continuous heat processing furnace (after a heating) of this invention. It is a figure which shows the principal part cross section of the longitudinal direction of the conventional continuous heat processing furnace (before heating). It is a figure which shows the principal part cross section of the longitudinal direction of the conventional continuous heat processing furnace (after a heating).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Muffle 2 Upper heater 3 Lower heater 4 Gas injection nozzle 5 Gas exhaust nozzle 6 Heat insulating material 7 Conveying belt 8 Support member 9 Caster 10 Receiving rail F Continuous heat treatment furnace 1a Furnace inlet 1b Furnace outlet B Heater block B1-B5 Heater block Unit A Muffle Movement Direction

Claims (3)

A heater equipped with a muffle and an atmosphere gas injection nozzle for forming the furnace atmosphere is fixed to the lower part of the muffle, and an exhaust nozzle for exhausting the atmosphere gas is fixed to the upper part of the muffle and arranged around the muffle And a heat insulating material arranged so as to surround the heater, a heater block is formed , and an electronic component provided with a transport belt for transporting an article to be processed from the entrance to the exit of the furnace through the muffle is fired. The heater block is divided into a plurality of units in the longitudinal direction of the furnace to form a plurality of units, each unit is fixed to the muffle, and the muffle is attached as the muffle is expanded by thermal expansion. A plurality of muffles arranged in the length direction of the muffle and fixed to a support member that supports the muffle, Continuous heat treatment furnace support member is characterized by being configured to be moved together with the muffle and the heater block in accordance with the stretching by muffle thermal expansion. The continuous heat treatment furnace according to claim 1, wherein the length of each unit is substantially the same, and the length of each unit is substantially the same as the arrangement interval of the support members. The continuous heat treatment furnace according to claim 1, wherein the support member includes a caster.

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