JP2000055564A - Roller hearth kiln - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate conditioning of atmosphere by supplying ambient gas into furnace chamber, arranging a seal cover on the outside of a furnace body and sealing the atmosphere in the furnace from the outer air thereby preventing the atmospheric gas from leaking through the gap of rollers. SOLUTION: A large number of rollers 3 arranged at a constant pitch over the entire length of a furnace chamber 2 transfers a product W mounted on a base board 4. Gas purge type seal covers 5 are arranged on the opposite sides of a furnace body 1 in order to seal the atmosphere in the furnace leaking through the gap of the rollers 3 from the outer air. Heaters 6, 7 are arranged vertically on the opposite sides of the roller 3 in order to heat the product W from upper and lower sides. Inside of the furnace chamber 2 is sectioned in the longitudinal direction by means of upper and lower barrier walls and each section is arranged with a gas supply pipe 10 in order to eject atmospheric gas obliquely toward the product W. A gas exhaust opening 11 for sucking and exhausting the atmospheric gas is made at the lower part of the furnace chamber 2 in order to suck and exhaust the atmospheric gas containing a binder gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller hearth kiln used for firing electronic parts and the like.

[0002]

2. Description of the Related Art Roller hearth kilns, which perform firing while transferring products by rollers, have been known for a long time.
Recently, a roller hearth kiln has been developed in which the inside of a furnace chamber of the roller hearth kiln is made a reducing atmosphere by hydrogen gas to perform reduction firing of electronic components and the like.

However, in the roller hearth kiln, generally, it is necessary to drive the rollers by exposing the ends of a large number of rollers for transferring products to the outside of the furnace body. It is inevitable that some atmospheric gas leaks. For this reason, various sealing means have been used, but it has been impossible to completely prevent the leakage of the atmospheric gas, and there has been a problem that it is difficult to adjust the atmosphere in the furnace by that much.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a roller hearth kiln capable of eliminating the leakage of the atmosphere gas from the gap between the rollers and facilitating the adjustment of the atmosphere. It was done for.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a roller hearth kiln in which the ends of rollers are exposed to the outside of a furnace body, and supplies an atmosphere gas to the inside of a furnace chamber. In addition, a seal cover is provided outside the furnace body to seal the atmosphere inside the furnace leaking from the gap between the rollers and the outside air. The seal cover is preferably of a gas purge type, and the seal covers are preferably provided on both sides of the furnace body. Further, it is preferable to provide gas boxes at the inlet and the outlet of the furnace chamber, respectively, to prevent the invasion of outside air from the inlet and the outlet of the furnace.The inside of these gas boxes is finely divided by a number of partition plates, and It is preferable to adopt a structure in which nitrogen gas or the like is supplied to the substrate.

In the roller hearth kiln of the present invention, the atmosphere inside the furnace leaking from the gap between the rollers can be sealed by the seal cover provided outside the furnace body, so that the atmosphere in the furnace chamber can be easily adjusted.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention, in which 1 is a roller hearth kiln furnace body,
Reference numeral 2 denotes a furnace chamber, and 3 denotes a number of rollers provided at a constant pitch over the entire length of the furnace chamber 2. As shown in FIG. 2, the roller 3 is for transferring the product W placed on the base plate 4, and in a normal roller hearth kiln, the end of the roller 3 and the drive unit are exposed outside the furnace body 1. However, in the roller hearth kiln of this embodiment, gas purge type seal covers 5 and 5 are provided on both sides of the furnace
To seal the atmosphere inside the furnace and the outside air leaking from the gap. Therefore, there is no change in atmosphere due to leakage of the atmosphere gas in the furnace, so that the atmosphere can be easily adjusted. Also, there is no danger when the atmosphere gas contains hydrogen gas.

[0008] In the vertical position sandwiching the roller 3 of the furnace chamber 2,
Heating heaters 6 and 7 are provided at appropriate intervals to heat the product W traveling on the roller 3 from both upper and lower surfaces. Although an electric heater is used as a heating source in this example, other heating sources such as a radiant tube can be used.

As shown in FIG. 1, the furnace chamber 2 is longitudinally partitioned by upper and lower partitions 8 and 9. And furnace room 2
A gas supply pipe 10 is provided in each section. The gas supply pipe 10 is provided at a position closer to the product W than the upper heater 6, and a gas supply port provided obliquely below the gas supply pipe 10, through which hydrogen gas and nitrogen gas are mixed for reduction firing. Is blown obliquely toward the product W running on the roller 3. Although the gas supply pipe 10 is provided at least in the temperature raising zone, other types of atmosphere gas supply means may be provided in other zones.

As shown in FIG. 1, the gas supply pipe 10 is provided at a position relatively close to the outlet side (right side) in each section. This is because a gas flow from the outlet to the inlet is generated inside the furnace chamber 2 and the atmosphere gas is ejected along with the gas flow. In addition, by rotating the gas supply pipe 10, it is possible to adjust the direction in which the atmospheric gas is ejected from the gas supply port. In this way, the binder gas staying near the surface of the product W can be blown off,
When the product W is a small electronic component, it is necessary to adjust the flow velocity so that the product W is not blown off.
The blowing speed of the atmospheric gas from the gas supply port is, for example, 15
m, but on the surface of the product W, the speed is 5 m / sec or less.

As shown in FIG. 2, a gas outlet 11 for sucking and exhausting atmospheric gas in the furnace chamber is provided at a lower portion of the furnace chamber 2. These gas outlets 11 are provided relatively on the inlet side of each section, and suck the atmospheric gas containing the binder gas which moves to the inlet side along with the above-mentioned gas flow, and exhausts the gas outside the furnace. As described above, the binder gas is heavy and easily stays in the lower part of the furnace chamber 2.
If the gas outlet 11 is provided at the lower part of the furnace, the binder gas generated from the product W can be efficiently removed from the furnace.

As shown in FIG. 1, gas boxes 12 and 13 are provided at the inlet and the outlet of the furnace chamber 2, respectively, and the inside thereof is finely divided by a large number of partition plates, and nitrogen gas or the like is supplied into the inside. By doing so, it is possible to simply and reliably prevent the entrance of outside air from the entrance and exit of the furnace. For this reason, it is more convenient for firing the atmosphere with a roller hearth kiln.

[0013]

As described above, the roller hearth kiln of the present invention can seal the atmosphere in the furnace leaking from the gap between the rollers against the outside air by the seal cover provided outside the furnace body. There is an advantage that the atmosphere in the furnace chamber can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view in a furnace width direction showing an embodiment of the present invention.

[Explanation of symbols]

1 Furnace body, 2 Furnace chambers, 3 Rollers, 4 Plates, 5 Seal covers, 6 Heater, 7 Heater, 8 Partition, 9 Partition, 10 Gas supply pipe, 11 Gas outlet, 12 Gas box, 13 Gas boxes, W products

Claims (5)

[Claims] In a roller hearth kiln in which an end of a roller is exposed to the outside of a furnace body, an atmospheric gas is supplied into a furnace chamber, and a seal cover is provided outside the furnace body to leak from a gap between the rollers. A roller heart kiln characterized by sealing the atmosphere inside the furnace and the outside air. 2. The roller hearth kiln according to claim 1, wherein the seal cover is of a gas purge type. 3. The roller hearth kiln according to claim 1, wherein seal covers are provided on both sides of the furnace body. 4. The roller hearth kiln according to claim 1, wherein a gas box is provided at each of an inlet and an outlet of the furnace chamber to prevent outside air from entering through an inlet and an outlet of the furnace. 5. The roller hearth kiln according to claim 4, wherein the inside of the gas box is finely divided by a number of partition plates, and nitrogen gas or the like is supplied into the inside.