JPH0134078Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a continuous thick film firing furnace.

(Prior art and its problems) To obtain thick-film IC products, pastes constituting conductors, dielectrics, or resistors are printed on an alumina or enamel substrate to create a circuit network. After drying the net and volatilizing the organic solvent, it is fired to sinter the paste and adhere it to the substrate.

As a device for carrying out this firing process, a continuous thick film firing furnace is widely used, in which an inlet tube, a furnace body, and an outlet tube (cooling tube) are connected in series, and a belt conveyor is passed between them.

Due to the nature of the product, this type of firing process needs to be carried out in a clean atmosphere and under strict temperature control, so the room where the continuous thick film firing furnace is installed is generally controlled with air conditioning equipment. However, the furnace body including the inlet tube is surrounded by a metal cover.

However, the firing process consists of burnout at a temperature below 500°C and main firing at approximately 900°C, and this is carried out continuously for a long time, so even if the cover is lined with a heat insulating material, the furnace body will be damaged. There was a problem in that the heat dissipated from the furnace body and cover accumulated and the temperature rose to such a level that it disturbed the air conditioning conditions in the room where the furnace body and cover were installed, deteriorating the working environment.

(Means for solving the problems) The present invention solves the problems of the conventional firing furnace as described above, can reliably prevent the temperature rise of the furnace body and cover, and can also properly control the substrate. The purpose of this project is to provide a continuous thick film firing furnace of this type that can perform cooling. Attach a guide casing with an opening facing between the cover and the furnace ceiling, and equip the guide casing with a fan (including a blower, hereinafter the same) with its outlet facing the cooling cylinder, and use this fan to suck in outside air and blow it into the cooling cylinder. The heated air inside the cover is efficiently drawn out by air-cooling the board passing through the cooling cylinder, and by letting the cooled air flow along the cover ceiling via the guide casing and out the exhaust part. It's about letting people know.

(Example) Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show a continuous thick film firing furnace according to the present invention, in which 1 is an inlet cylinder, 2 is a furnace body, 3 is a cooling cylinder, which are connected in series on a base 4, A conveyor belt 5 transports a substrate as an object to be processed. An outlet section 30 having a gas curtain section 31 is connected to the end of the cooling tube 3, a heater 7 is disposed inside the furnace body 2, a furnace core tube 6 is passed through the inside of the heater 7, and the inlet tube 1 is connected to the end of the cooling tube 3. and the cooling cylinder 3.

8 is a cover that surrounds the inlet cylinder 1, the furnace body 2, and the cooling cylinder 3, and has a box-shaped cross section;
An exhaust section 9 is provided at a ceiling position near the inlet tube 1.

Reference numeral 10 denotes a guide casing that surrounds the cooling cylinder 3 in the cover 8, and is connected to the flanges 32, 32 of the cooling cylinder 3 at its side ends, and the upper part is connected to the cover 8 and the furnace ceiling. A discharge port 101 facing between the portions 21 is opened, and a guide slope 102 is formed at the back of the discharge port 101. Further, inside the guide casing 10, fans 11, 11 whose blow-off ports face the cooling cylinder 3 are disposed, and an opening 103 for taking in outside air is formed below the fans 11, 11. fan 1
1 and 11 are preferably used with a large air volume.

In other drawings, 12 is an atmospheric gas introduction part, 1
3 is a burnout gas discharge part, and cover 8
It is located in the exhaust part 9 of.

Since the present invention has the above-mentioned configuration, the substrate on which the paste is printed is placed on the conveyor belt 5 in front of the inlet cylinder 1, the heater 7 is activated, and at the same time, an atmosphere containing a predetermined component is introduced from the atmosphere introduction part 12. As a result, the resin binder contained in the paste is volatilized and burned, and is emitted from the exhaust section 13 to the outside via the exhaust section 9. Subsequently, the substrate is heated at a high temperature while being transferred, thereby sintering the paste and bonding it to the substrate, and reaches the cooling cylinder 3.

During this operation, the present invention operates the fans 11, 11, whereby outside air is drawn into the guide casing 10 through the lower opening 103 of the guide casing 10 and blown onto the cooling tube 3. As a result, the substrate passing through the cooling tube 3 is indirectly air-cooled.

Since the air flow that cools the board has a large air volume, the temperature rise is small.
02 to the discharge port 101, from where it is ejected into the space 14 between the cover 8 and the furnace ceiling 21.

As shown in FIG. 1, the ejected air flow flows through the space 14 from the outlet direction to the inlet direction of the furnace body 2, and during this time, the heated air rising from the furnace body 2 by natural convection is pushed out and the exhaust section 9 be released from. Accordingly, the upward flow of heated air from the side surfaces 22, 22 of the furnace body is promoted, and the heated air is discharged along with the air flow. Since this continues during operation, the temperature between the furnace body 2 and the cover 8 is maintained in a sufficiently lowered state, and disturbances in air conditioning due to heat radiation from the cover do not occur.

Note that the fans 11, 11 that cool the substrate are
A guide casing 10 that does not directly surround the cover 8 but partitions the cooling cylinder 3 in front of the outlet portion 30.
Since air is sucked through the opening 103 at the bottom of the furnace and guided to the discharge port 101 at the top of the guide casing 10, there is no need to disturb the atmosphere inside the furnace.

(Effects of the invention) According to the invention described above, the substrate after heating and firing can be appropriately cooled, and the air as the cooling medium is used to reliably prevent the temperature rise between the furnace body and the cover. Even during continuous operation, excellent effects such as maintaining a safe working environment without disturbing the air conditioning can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an embodiment of a continuous thick film firing furnace according to the present invention, and FIG. 2 is a cross-sectional view thereof. 1... Inlet tube, 2... Furnace body, 3... Cooling tube, 8
... Cover, 9 ... Exhaust section, 10 ... Guide casing, 11 ... Fan, 101 ... Discharge port.

Claims (1)

[Scope of utility model registration request] The furnace body including the inlet cylinder is surrounded by a cover with a space left, and an exhaust part is provided at a position offset to the end of the cover, and around the cooling cylinder, the discharge port is located between the cover and the ceiling of the furnace body. This continuous thick film firing furnace is equipped with a guide casing that faces the cooling cylinder, and is equipped with a fan inside the guide casing that directs the air outlet toward the cooling cylinder.