JPH08121971A - Baking furnace - Google Patents

Abstract

PURPOSE: To reduce the length of a tunnel type baking furnace and improve the thermal efficiency. CONSTITUTION: An inlet and an outlet are parallely provided at one end of a tunnel type furnace body 1, and a conveyor is installed in the furnace body 1 which conveyor conveys a basket 51 containing a work W from an inlet part to an outlet part through a conveyance passage in the furnace, and a duct 5 extending in the direction of the length of the furnace and including a plurality of hot air blowoff outlets 8 is provided in the furnace ceiling. There are provided a circulation fan for feeding furnace air from an air suction port provided at the other end of the furnace body into the duct 5 and heating means disposed on the upstream or downstream side of the circulation fan for heating air supplied into the ducty. A hot air blowing fan 60 is provided between a hot air blow port 71 provided on the upper part of a conveyance passage on the side of a foreward passage near the inlet and opened downward and a hot air takeout port 72 provided in the duct 5 for blowing out hot air sucked from the hot air takeout port from the hot air spray outlet 71.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a baking furnace used for removing hydrogen embrittlement of a work in a plating process, and more particularly to a continuous baking furnace.

[0002]

2. Description of the Related Art As a baking furnace of this type, a conveyor for conveying baskets containing work is provided in a tunnel-shaped furnace body, and the conveyor is used to continuously move the work at a low speed. Conventionally, a type of heating with hot air while being transported in the furnace is used.

[0003]

However, in the furnace of the above type, after the work is carried into the furnace from the inlet of the furnace body,
It takes a long time (for example, 1 to 1.5 hours) to reach the predetermined holding temperature (for example, 200 ° C.), and then the holding temperature is held for the predetermined time (for example, 4 hours). There is a problem that the traveling distance in the furnace, that is, a long furnace length is required, the facility cost and the installation space are large, and the heat loss from the furnace body is large.

The present invention solves the above-mentioned problems of the prior art, that is, the temperature rise time from when the work is carried into the furnace to when it reaches a predetermined holding temperature, that is, the work during the temperature rising process. An object of the present invention is to provide a baking furnace capable of shortening the furnace length and improving the thermal efficiency because the traveling distance is short.

[0005]

A baking furnace according to the first invention of the present application has an inlet and an outlet arranged in parallel at one end of a tunnel-shaped furnace body, and an intake port at the other end of the furnace body. And a conveyor that conveys the basket containing the work from the inlet portion to the outlet portion via the conveying path in the furnace is installed in the furnace body and extends in the furnace length direction and has a plurality of hot air outlets. A duct is provided in the furnace ceiling, and a circulation fan that blows in-furnace air sucked from the intake port into the duct, and an air that is arranged upstream or downstream of the circulation fan and is supplied into the duct are provided. A heating means for heating is provided, and between the hot air blowing opening provided on the downward path provided on the forward path side close to the inlet and the hot air taking opening provided in the duct, from the hot air taking outlet. Let the hot air sucked in be blown out from the hot air blowing port. Characterized in that a fan with hot air.

The baking furnace of the second invention of this application has an inlet and an outlet arranged in parallel at one end of a tunnel-shaped furnace body.
An intake port is provided at the other end of the furnace body, and a conveyor is installed in the furnace body to convey a basket containing a work from the inlet portion to the outlet portion through a conveying path in the furnace. A duct having a plurality of hot air outlets extending to the furnace ceiling, and a circulating fan that blows the in-furnace air sucked from the intake port into the duct, and is arranged upstream or downstream of the circulating fan. And a heating means for heating the air supplied to the inside of the duct, and a downward opening hot air blowing port provided above the transport path on the outward path near the inlet and a hot air outlet provided in the duct. A hot air blowing fan for blowing hot air sucked from the hot air outlet from the hot air blowing port is provided between the hot air blowing port and the hot air blowing fan, and the upward blowing is provided on the hearth part of the transfer path on the outward path near the inlet. Distinction between the mouth and the hearth In between the lower outlet provided, characterized in that a lower circulation fan for blown furnace air sucked from the lower outlet from the upflow port.

In the present invention, if the hot air outlet has a rectangular shape whose longitudinal direction is oriented in the conveying direction of the conveyor, the hot air is blown in a wide width in the conveying direction.
It is particularly preferable because the contact time between the work and hot air is long and the temperature rising rate of the work is fast.

[0008]

In the present invention, the hot air in the duct is blown downward from the hot air blowing port at a high speed by the hot air blowing fan to the basket containing the low temperature work carried in from the inlet, The temperature rise of the work is promoted,
The time required for the chamber to heat up to a predetermined holding temperature, that is, the conveying distance in the furnace can be reduced.

According to the second aspect of the invention, in addition to the hot air blowing from above by the hot air blowing fan, the hot air supplied from the duct into the furnace passes through the lower outlet of the hearth floor to form the lower circulation fan. Is sprayed at high speed from the blow-up port to the basket containing the work, and is then carried in from the inlet.
The temperature of the work, especially the work of the lower layer in the basket, is promoted, so that the entire work is soaked.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the figure, reference numeral 1 is a tunnel-shaped furnace body, and an inlet 2 for carrying in and an outlet 3 for carrying out a basket 51 accommodating a work W are juxtaposed at one end 1a thereof. Further, as shown in FIG. 3, an intake port 4 is formed at the other end 1b of the furnace body 1. Reference numeral 5 indicates that the upper part of the furnace body 1 is divided into upper and lower parts by a partition plate 6, and a hot air supply path 7 is provided between the ceiling wall 11 and the partition plate 6.
The partition plate 6 has a large number of hot air outlets 8 formed therein, and each hot air outlet 8 is provided with a slide shutter type damper 9 for adjusting the air volume. .

Reference numeral 20 denotes a circulation fan composed of a multi-blade fan provided at the upper corner of the other end 1b of the furnace body 1, and a slender impeller 22 having a central axis 21 extending in the furnace width direction is freely rotatable on a casing 23. The discharge port 24 of the casing 23 is connected to the end of the duct 5 through the air supply port 10 formed in the upper part of the furnace end wall, and the suction port 25 is connected to the suction port 4. There is.

The impeller 22 has a large number of elongated blades 26 having a concavely curved cross section with respect to the rotational direction thereof, which are arranged side by side on the circumference, and both ends of which are fixed to a disc 27, and the disc 27 is fixed. A support shaft 28 is provided so as to project at 27, and the belt is driven by a motor 30. Further, the casing 23 has the rectangular suction port 25 that extends downward in the furnace width direction and opens downward.
And a rectangular discharge port 24 that opens in a plane orthogonal to this
Has a curved flow path 29 extending to
It is housed in 9.

Reference numeral 35 denotes a gas burner for heating air, which is provided on the downstream side of the circulation fan 20 (in front of the discharge port 24).
It is attached to one side wall 12 of the furnace body 1, and a high temperature combustion gas is discharged into the duct 5 to heat the air discharged from the circulation fan 20 and supply the air into the duct 5. Reference numeral 35a is a tube for holding flame.

Reference numeral 40 denotes a reversing portion 42 in the furnace near the other end 1b from above a base frame 41 provided outside one end 1a of the furnace body 1.
With the chain conveyor provided over the chain, the chain 46 wound between the drive sprocket 44 of the drive unit 43 and the driven sprocket 45 of the reversing unit 42 is used as a driving body, and the conveyance on the forward side extending in the furnace length direction is performed. It has a path 47a and a return path 47b. Reference numeral 49 is a rail provided along the movement path of the chain 46, 50 is a carriage mounted on the rail 49 so as to be freely movable, and 51 is a support parallel to the traveling direction on the carriage 50. Arrow R around axis 52 (see Figure 4)
The basket 50 is supported so as to be tiltable to the side, as shown by, and the carriage 50 is connected to the chain 46 by an attachment 53. Reference numeral 54 is a guide rail for guiding the chain 46. This dolly 50 and basket 51
Are connected to the chain 46 at small intervals, but only a part of them is shown in the figure. The rail 49 and the guide rail 54 are fixedly attached to the furnace body 1 by a support beam (not shown).

Side plate 51a and bottom plate 5 of basket 51
The portion 1b is made of a perforated steel plate having air permeability, and in the basket 51, a plating component to be subjected to a baking process is struck from a shoe 55 above the drive unit 43 (see FIG. 1). The work W supplied with the crank W, traveling in the furnace from the inlet 2 and subjected to the baking treatment, is moved to the side indicated by the arrow R by the pneumatic cylinder type pusher 56 provided near the outside of the outlet 3. Inclining toward the side and carrying out the work W, a shoe 57
After being carried out to the section, a guide mechanism (not shown) returns to an upright state in which it opens upward. The illustration of the side plate 51a of the basket in a perforated state and the support structure of the cylinder portion of the pusher 56 are omitted.

The cross section of the furnace body 1 perpendicular to the furnace length direction has a rectangular shape, but in the portion near the one end 1a of the furnace body 1, the corner portion of the furnace body above the transport path 47a on the outward path side. Is cut into a square shape to form a concave portion 13 (see FIG. 6). In this embodiment, two hot air blowing fans 60 are formed in the concave portion 13.
Are installed at intervals in the furnace length direction. Recess 13
On the bottom wall 14 (the ceiling wall that has become low when viewed from inside the furnace)
A rectangular downward hot air blowing port 71 extending in the conveyor conveying direction (furnace length direction) is formed along the conveyor path 47a of the chain conveyor 40, and the side wall 15 of the concave portion 13 (width as viewed from the inside of the furnace is formed. A hot air outlet 72, which also extends in the furnace length direction, is formed in the narrowed side wall of the duct 5.

The hot air blowing fan 60 is a multi-blade fan having the same structure and structure as the circulation fan 20 described above, and is a slender impeller 62.
Of the casing 63 is arranged with the central axis 61 thereof oriented in the conveying direction of the chain conveyor 40 (furnace length direction), and a rectangular discharge port 64 extending in the furnace length direction of the casing 63 is provided at the hot air blowing port 71 and also in the furnace length. Rectangular suction ports 65 extending in the direction are connected to the hot air outlets 72, respectively, and the impeller 62 is belt-driven by the motor 70. Since the structures of the impeller 62 and the casing 63 are the same as those of the circulation fan 20, detailed description thereof will be omitted.

On the other hand, at the intermediate position between the two hot air blowing ports 71, 71, the hearth 16 of the furnace body 1 is projected downward in a box shape, and a concave chamber 17 extending in the furnace length direction at the center of the furnace width.
Is formed (see FIG. 7), and its upward opening serves as a rectangular lower outlet 91 extending in the furnace length direction,
Adjacent to the lower outlet 91, the transport path 47 on the forward path side
In the hearth 16 below a, a rectangular blowing port 92 extending in the conveyor conveying direction (furnace length direction) along the conveying path 47a.
Has been drilled.

Reference numeral 80 denotes a lower circulation fan provided immediately below the blow-up port 92, which is a multi-blade fan having the same type and structure as the circulation fan 20 described above, and a central shaft 81 of an elongated impeller 82 is connected to the chain conveyor 40. Of the casing 83, the rectangular discharge port 84 extending in the furnace length direction of the casing 83 is provided at the blow-up port 92, and the rectangular suction port 85 also extending in the furnace length direction. Each of them is connected to an intake port 93 formed in the side wall 18 of the recessed chamber 17, and the impeller 82 is belt-driven by the motor 90. Since the structures of the impeller 82 and the casing 83 are the same as those of the circulation fan 20, detailed description thereof will be omitted.

Next, a method of operating the baking furnace 100 having the above structure will be described. First, operate the circulation fan 20,
When the fuel gas is burned by the gas burner 35 and the heated air is fed into the duct 5, the hot air is supplied downward from the hot air outlet 8 into the furnace as hot air, and the other end 1b is fed into the furnace.
And flows from the intake port 4 to the suction port 25 of the circulation fan 20. Further, the hot air blowing fan 60 is operated so that the hot air sucked from the hot air outlet 72 of the duct 5 is blown by the hot air blowing port 7
The hot air is blown downward from 1 at a higher speed than the hot air from the hot air outlet 8. Furthermore, the lower circulation fan 80 also operates,
Hot air in the furnace (lower temperature than hot air in the duct) is sucked from the lower outlet 91 and blown upward from the blow-up port 92 at high speed.

When the chain conveyor 40 is operated (tact operation), the empty baskets 51 are sequentially provided with the work W from the shunt 55 in the vicinity of the chain reversing portion in the drive unit 43 outside the furnace. After being loaded, this basket 51 is loaded into the furnace from the inlet 2 together with the trolley 50, and when the basket 51 first passes below the hot air blowing port 71 near the inlet 2, it moves downward from the hot air blowing port 71 at a high speed. The work W in the basket 51 is heated by the hot air of the basket 51, and when the work W next passes over the blow-up port 92, the upward high-speed hot air from the blow-up port 92 passes through the bottom plate 51b of the basket 51 and the work. The work W is heated by the high-speed hot air from the hot air blowing port 71 while heating the lower part of the deposited layer where the temperature of W slowly rises, and subsequently passing below the other hot air blowing port 71, Communication of these parts Click W is heated to a predetermined holding temperature close in a short time - Wa by.

After that, the hot air outlet 8 of the duct 5 is exclusively used.
Work air by the hot air from the inside, more specifically, by blowing the hot air and the atmosphere in the furnace kept at a high temperature by the hot air.
Is heated and the temperature is maintained. Each of the baskets 51 transferred from the forward side transport path 47a to the return side transport path 47b in the reversing section 42 is transferred from the outlet 3 of the furnace body 1 to the outside of the furnace after being kept in the furnace for a predetermined time by being transported in the furnace. From the basket 51 that has been carried out and tilted to the side indicated by the arrow R by the pusher 56, the baking-worked work W is carried out to the carry-out shoe 57, and then to the drive unit 43. After being transferred, a new untreated work W is charged by the shoot 55, and thereafter the same steps as above are repeated.

The present invention is not limited to the above-described embodiment, and other types of conveyors such as a roller conveyor may be used as the basket-conveying conveyor, and the basket may be used as in the above-mentioned embodiment. Is connected to a conveyor for loading and unloading the work into and from the basket, as well as a basket containing unprocessed work, for example, the carriage 50 or the roll in the above embodiment.
It is also possible to use a conveyor and a basket of a type in which the basket is transferred onto a supporting member such as a conveyor roller of a la conveyor and the basket is taken out from the supporting member after processing. Further, in addition to the U-turn type transfer path described above, the conveyor may have a bent transfer path that is inverted at a plurality of (for example, three) inversion portions 42 in the furnace.

As the heater for heating the air supplied into the duct, an electric heat heater or the like may be used in addition to the above-mentioned gas burner 35, and the arrangement thereof is on the upstream side of the circulation fan, that is, It may be on the upstream side of the suction port. Further, the number of hot air blowing ports 71 may be one or three or more. Depending on the shape of the work, the number of baskets accommodated in the basket, the shape of the basket, the air permeability, etc., the blowing of the hot air by the blowing port and the lower circulation fan is not possible. It may be omitted.

Further, in the above-mentioned embodiment, the hot air blowing port 71 and the blowing port 92 are formed in a rectangular shape whose longitudinal direction is oriented in the conveying direction of the conveyor, so that the hot air is wide in the conveying direction from these openings. Since it is sprayed, it has the advantage that the work time for the work and the hot air is long and the temperature rising rate of the work is fast, but these openings may have other shapes. Further, in the above-described embodiment, as the hot air blowing fan 60 and the lower circulation fan 80, an elongated impeller in which elongated blades are circumferentially arranged side by side in a casing having a discharge opening having a rectangular opening shape. Since the multi-blade fan rotatably supported is used, it has an advantage that it can supply a wide hot air having a uniform flow velocity distribution to the rectangular hot air blowing port 71 and the blowing port 92. However, other types of fans can be used.
Similarly, as the circulation fan 20, a fan of a type other than the slender multi-blade fan of the above embodiment can be used.

[0026]

As described above, according to the present invention,
By blowing hot air from the hot air blowing port provided near the inlet of the furnace body, and in addition to this, blowing hot air from the blowing port provided near the inlet to the work inside the basket. The heating time of the work is accelerated, the time required for the work to heat up to a predetermined holding temperature, and thus the conveying distance in the furnace, is shortened, and thereby the furnace length can be shortened. Since the heat radiation from the furnace body is reduced as the furnace length is shortened, the thermal efficiency is also improved.

[Brief description of drawings]

FIG. 1 is a front view of a baking furnace according to an embodiment of the present invention cut at an intermediate portion.

FIG. 2 is a partially cutaway plan view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a side view taken along the line CC of FIG.

FIG. 5 is a plan view of a DD section of FIG.

6 is a cross-sectional view taken along the line EE of FIG.

FIG. 7 is a sectional view taken along line FF in FIG.

[Explanation of symbols]

1 ... Furnace body, 1a ... One end, 1b ... Other end, 2 ... Inlet, 3
… Exit, 4… Intake port, 5… Duct, 8… Hot air outlet, 1
0 ... Air supply port, 16 ... Hearth, 20 ... Circulation fan, 24 ... Discharge port, 25 ... Suction port, 35 ... Gas burner, 40 ... Chain
Conveyor, 46 ... Chain, 47a ... Forward transport path, 50 ... Truck, 51 ... Basket, 60 ... Hot air blowing fan, 64 ... Discharge port, 65 ... Suction port, 71 ... Hot air blowing port, 72 ... Hot air Outlet, 80 ... Lower circulation fan, 84 ...
Discharge port, 85 ... Suction port, 91 ... Lower outlet port, 92 ... Blowing port, 100 ... Baking furnace, W ... Work.

Claims (3)

[Claims] 1. A tunnel-shaped furnace body having an inlet and an outlet arranged in parallel at one end thereof, and an intake port provided at the other end of the furnace body, and a basket containing a work is inserted from the inlet to the inside of the furnace. A conveyor that conveys to the outlet via a conveying path is installed in the furnace body,
A duct that extends in the furnace length direction and has a plurality of hot air outlets is provided in the furnace ceiling, and a circulation fan that blows the in-furnace air sucked from the intake port into the duct, and an upstream side or a downstream side of the circulation fan. And a heating means for heating the air supplied to the duct disposed on the side, and provided on the duct and a downward-opening hot air blowing port provided above the transport path on the outward side near the inlet. A baking oven characterized in that a hot-air blowing fan for blowing hot air sucked from the hot-air outlet from the hot-air outlet is provided between the hot-air outlet and the hot-air outlet. 2. A tunnel-shaped furnace body having an inlet and an outlet arranged in parallel at one end thereof, and an intake port provided at the other end of the furnace body, and a basket containing a work is inserted from the inlet to the inside of the furnace. A conveyor that conveys to the outlet via a conveying path is installed in the furnace body,
A duct that extends in the furnace length direction and has a plurality of hot air outlets is provided in the furnace ceiling, and a circulation fan that blows the in-furnace air sucked from the intake port into the duct, and an upstream side or a downstream side of the circulation fan. And a heating means for heating the air supplied to the duct disposed on the side, and provided on the duct and a downward-opening hot air blowing port provided above the transport path on the outward side near the inlet. A hot air blowing fan that blows hot air sucked from the hot air outlet from the hot air blowing port is provided between the hot air taking port and the hot air blowing port that is provided at the hearth portion of the transfer path on the outward path side close to the inlet. A lower circulation fan that blows out the in-furnace air sucked from the lower outlet from the upper outlet is provided between the opening upper outlet and the lower outlet provided at another position of the hearth. Baking furnace 3. The baking furnace according to claim 1, wherein the hot air blowing port has an opening shape that is a rectangular shape whose longitudinal direction is oriented in the conveying direction of the conveyor.