JP7259776B2 - Drying equipment and drying method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a drying apparatus and a drying method for supporting a workpiece coated with a slurry film on a predetermined portion by a setter and drying the workpiece with hot air.

A known example of this type of work is a gas sensor element used for combustion control of an internal combustion engine. The gas sensor element comprises a cylindrical solid electrolyte body having a reference gas chamber therein, inner and outer electrodes formed on the inner and outer surfaces of the solid electrolyte body, and a porous layer covering the outer electrode. It's becoming

When manufacturing the gas sensor element, the solid electrolyte body is immersed in the slurry in the dip bath, the slurry is applied to a predetermined portion of the gas sensor element, and immediately after that, the gas sensor element is carried into a drying device, and heated in a drying furnace. After the slurry film is dried, it is fired to form a porous layer.

As a conventional drying device, Patent Document 1 describes a device in which a drying furnace is arranged above a tank filled with a coating liquid, and one sample is pulled up into the drying furnace immediately after being immersed in the coating liquid and dried. It is Patent Literature 2 also describes an apparatus in which one gas sensor element is vertically accommodated in a holding portion, and a plurality of holding portions are carried into a drying furnace by a conveyor.

In addition, in order to improve processing efficiency, a plurality of gas sensor elements are supported by a setter made of ceramics, the setter is placed on a pallet, and the plurality of pallets are successively conveyed into the drying furnace by a conveyor. There is also known a pass-through drying apparatus that blows hot air onto a pallet to simultaneously dry a plurality of gas sensor elements supported by the pallet.

JP 2006-116427 A JP 2018-54547 A

However, while the conventional pass-through dryer can efficiently process a large number of gas sensor elements, it blows hot air onto the workpieces passing through the drying furnace with open inlets and outlets. of heat source. As a result, the hot air emitted from the drying furnace is trapped inside the equipment, adversely affecting the environment around the drying apparatus, and the overall size of the apparatus is increased.

Therefore, a batch drying method is conceivable, in which one batch of works is supported by a setter and placed in a drying furnace, the door of the drying furnace is closed and hot air is applied, and after drying, the door is opened and the works are taken out. Compared to the passing type, the batch type makes it easier to keep the furnace temperature constant, making it suitable for uniform drying of the slurry film after application. It is easy to use and can be easily applied to both stand-alone and automated equipment.

However, since a plurality of works are carried into the drying furnace together with the setter, the volume of the drying furnace becomes large. As a result, when the door is opened, a large amount of hot air escapes to the outside of the furnace, causing the temperature inside the furnace to drop quickly. There is Moreover, since the members to be heated in the drying furnace include not only the workpiece but also the setter, there is a problem that the amount of heat mass for one batch increases and the tact time is extended.

The present invention has been made in view of the above problems, and its object is to provide a drying apparatus and a drying method for efficiently drying a plurality of works supported on a setter in a drying furnace with hot air. .

In order to solve the above problems, the drying apparatus (10) of the present invention includes a setter (4) for supporting a plurality of works (1) coated with a slurry film (3) at predetermined portions, and a work entrance (28). and a drying furnace (11) formed with a drying chamber (25), a door member (23) for opening and closing the entrance and exit of the workpiece, and blowing hot air into the drying chamber when the door member closes the entrance and exit of the workpiece. and a blower mechanism (13). The setter is attached to a door member, and the door member is configured to place a predetermined portion of the work inside the drying chamber while the setter is positioned outside the drying chamber when the entrance of the work is closed. The drying furnace is provided with a shutter (30) for closing the work entrance instead of the door member when the door member opens the work entrance.

The drying method of the present invention comprises a step (S1) of supporting a plurality of works (1) coated with a slurry film (3) on predetermined portions on a setter (4); A step (S3) of opening the doorway (28), a step of closing the door member (23) to which the setter is attached, closing the work doorway (28), and carrying the work into the drying chamber (25) of the drying furnace. (S4), a step of passing hot air through the drying chamber to dry a predetermined portion of the work by the hot air for a predetermined time (S5), and a step of opening the door member after the predetermined time has passed and carrying the work out of the drying chamber. (S6), a step (S7) of closing the shutter to close the workpiece entrance, and a step (S8) of removing the workpiece from the setter. Then, in the step of carrying the work into the drying chamber, a predetermined portion of the work is placed inside the drying chamber while the setter is positioned outside the drying chamber.

According to the drying apparatus and drying method of the present invention, when the door member closes the work entrance of the drying furnace, the setter is positioned outside the drying chamber, and only a predetermined portion of the work is placed inside the drying chamber. A slurry film applied to a predetermined portion can be efficiently dried with hot air.

1 is a schematic diagram showing a drying apparatus of one embodiment according to the present invention; FIG. (a) is a cross-sectional view showing a gas sensor element coated with a slurry film, and (b) is a partially enlarged view of the gas sensor element showing a water-containing state. (a) is a plan view of the setter, and (b) is a sectional view of the setter. It is a perspective view which shows the whole arrangement|positioning of each part of drying apparatus. 5 is a view in the direction of arrow V in FIG. 4; FIG. 5 is a view in the direction of arrow VI in FIG. 4; FIG. FIG. 4 is a cross-sectional view showing the drying furnace when the door member opens the workpiece entrance; FIG. 4 is a cross-sectional view showing the drying furnace when the door member closes the work entrance; FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8 showing the rectifying member; 4 is a flow chart showing a method for drying a gas sensor element; FIG. 4 is a cross-sectional view of a drying oven showing another embodiment of the present invention; FIG. 5 is a cross-sectional view of a straightening member showing another embodiment of the present invention; (a), (b) is explanatory drawing which shows the effect|action of the heat insulating material in other embodiment of this invention.

<One embodiment>
An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the drying apparatus 10 of the present embodiment includes a drying furnace 11 for drying the gas sensor element 1, a loader 12 for carrying the gas sensor element 1 into and out of the drying furnace 11, and blowing hot air HW to the drying furnace 11. A blower mechanism 13 is provided. The blower mechanism 13 includes a blower 14, a heater 15, and a circulation pipe 16. Air blown from the blower 14 is heated by the heater 15, passed through the drying furnace 11, and then returned to the blower 14 via the circulation pipe 16. is configured as

As shown in FIG. 2(a), the gas sensor element 1 as a workpiece is immersed in slurry S in a dip bath (not shown) in a step (dipping step) in which a cylindrical solid electrolyte body 2 closed at one end is dipped. A slurry film 3 is applied to a predetermined portion of the outer surface of the gas sensor element 1 (the range indicated by the dashed line in the figure). As shown in FIG. 2B, since the solid electrolyte body 2 immediately after the immersion contains water W, in the drying process following the dipping process, hot air HW is applied to the slurry film 3 to dry the slurry film 3. At the same time, the moisture W is evaporated from the inside of the solid electrolyte body 2 to manufacture the gas sensor element 1 of a predetermined mass.

As shown in FIGS. 3(a) and 3(b), the drying device 10 uses a ceramic setter 4 to process a plurality of gas sensor elements 1 in batches. A plurality of support holes 5 are formed in the setter 4 so as to be arranged vertically and horizontally at regular intervals, and the base portion 101 of the gas sensor element 1 is inserted into each of the support holes 5 . A leg portion 102 of the gas sensor element 1 corresponding to the application range of the slurry film 3 is exposed outside the support hole 5 and exposed to the hot air HW inside the drying furnace 11 . The number of gas sensor elements 1 for one batch is not limited to the number shown in FIG. 1 or 3, and can be arbitrarily increased or decreased.

As shown in FIGS. 4, 5, and 6, the drying furnace 11 is installed on a frame 18, and a loader 12 is provided below the frame 18 so as to be reciprocatable along rails 20 by a horizontal drive unit 19. ing. The loader 12 includes a lift plate 21 and a vertical drive portion 22 thereof, and a door member 23 is attached on the lift plate 21 . The setter 4 is placed on the door member 23, and the loader 12 moves up and down the door member 23 at the drying position (the chain line position in FIG. 5) directly below the drying furnace 11 to dry the gas sensor element 1 supported by the setter 4. It is carried in and out of the furnace 11 .

As shown in FIG. 7, the main body 110 of the drying furnace 11 is formed in a hollow rectangular box shape, and the hollow portion serves as a drying chamber 25 for drying the gas sensor element 1 . A recess 27 for reducing the volume of the drying chamber 25 is formed in the upper lid 26 of the drying oven 11 . A heat insulating material 24 is provided on the lower surface of the upper lid 26 to fill the excess space of the drying chamber 25 . On the other hand, a work entrance 28 is formed on the lower surface of the drying furnace 11 , and the door member 23 is moved up and down by the loader 12 between an open position for opening the work entrance 28 and a closed position for closing the work entrance 28 .

As shown in FIG. 8, when the door member 23 is raised to the closed position, the upper end surface of the peripheral wall of the door member 23 is in close contact with the lower surface of the body 110 of the drying oven 11 to close the work entrance 28. At this time, the upper surface of the setter 4 is positioned at substantially the same height as the bottom surface of the drying chamber 25 , and the rest of the setter 4 except for the upper surface is positioned outside the drying chamber 25 . The gas sensor element 1 is exposed to the inside of the drying chamber 25 only at a predetermined portion where the slurry film 3 is applied, that is, only the leg portion 102 . The thickness of the heat insulating material 24 is set so that the volume of the drying chamber 25 is minimized in this state.

A guide 29 is provided below the work inlet/outlet 28 . A shutter 30 is supported by the guide 29 so as to be slidable in the work inlet/outlet 28, and driven horizontally by a cylinder 31 (see FIG. 6). The shutter 30 closes the work entrance 28 instead of the door member 23 immediately after the door member 23 descends to the open position, and opens the work entrance 28 immediately before the door member 23 rises to the closed position. Therefore, when the gas sensor element 1 is carried in and out, there is no possibility that the drying chamber 25 is left open for a long time.

A hot air inlet 33 is formed at one end of the drying furnace 11, and a hot air outlet 34 is formed at the opposite end. In the vicinity of the hot-air inlet 33, an inlet-side straightening member 35 and an adjustment plate 36 are provided. is adjusted. In the vicinity of the hot air outlet 34, there are provided an outlet-side rectifying member 37 that collects the hot air HW in the drying chamber 25 and guides it to the circulation pipe 16, and an adjustment plate 38 that adjusts the outflow speed of the hot air HW. A temperature sensor 39 (see FIG. 6) for measuring the temperature of the hot air HW is installed in the inlet-side straightening member 35 .

As shown in FIGS. 9A and 9B, inside the inlet-side straightening member 35, a plurality of straightening vanes 41 are arranged in a broom shape. The rectifying plates 41 are held parallel to each other at substantially equal intervals by rods 42, and distribute the hot air HW flowing into the drying chamber 25 evenly to the plurality of rows of gas sensor elements 1 on the setter 4. to circulate in the air blowing direction. The adjustment plate 36 spreads over the entire width of the drying chamber 25 along the inner wall plate 43 of the drying furnace 11, and by adjusting the height of the adjustment plate 36 with the adjuster 44, the amount of hot air distributed to the plurality of air passages is adjusted. Each part can be adjusted equally. The outlet-side rectifying member 37 and the adjustment plate 38 are also constructed in the same manner as those on the inlet side.

Next, a drying method for the gas sensor element 1 will be described with reference to FIG. In this embodiment, the drying process is started immediately after the dipping process in order to shorten the manufacturing time of the gas sensor element 1 . First, at the standby position (solid line position in FIG. 5) of the loader 12, a plurality of gas sensor elements 1 coated with the slurry film 3 are supported by the setter 4 (S1). Next, the loader 12 advances from the standby position to the drying position (position indicated by the dashed line in FIG. 5), and the setter 4 is placed directly below the drying oven 11 (S2).

Next, the shutter 30 is opened to open the workpiece entrance 28 of the drying furnace 11 (S3). Subsequently, the loader 12 raises the door member 23 by the lifting plate 21, closes the work entrance 28 with the door member 23, and carries the gas sensor element 1 into the drying chamber 25 (S4). At this time, the setter 4 is positioned outside the drying chamber 25 and closes the bottom surface of the drying chamber 25, so that only the legs 102 of the gas sensor element 1 are arranged inside the drying chamber 25 (see FIG. 8). In this state, the blower 14 is driven for a predetermined time, the hot air HW is supplied into the drying chamber 25 through the inlet-side rectifying member 35, and the slurry films 3 of the plurality of gas sensor elements 1 are simultaneously blown by the hot air HW. It is dried (S5).

The hot air HW dispersed in the drying chamber 25 is collected by the outlet-side rectifying member 37 and discharged from the drying chamber 25 to the circulation pipe 16. is reheated by the heater 15 according to the detected temperature. When the predetermined drying time expires, the blower 14 is stopped, the door member 23 is lowered from the closed position to the open position, the work entrance 28 is opened, and the gas sensor element 1 is carried out of the drying chamber 25 (S6). Immediately after that, the shutter 30 is closed to close the workpiece entrance 28 in place of the door member 23 (S7). Thereafter, the loader 12 returns from the drying position to the standby position, where the gas sensor element 1 after drying is taken out from the setter 4 (S8).

Therefore, according to the drying device 10 of this embodiment, the following effects can be obtained: (a) During drying, the setter 4 is positioned outside the drying chamber 25, and only the leg portions 102 of the gas sensor element 1 are Since it is arranged in the drying chamber 25, the amount of heat mass for one batch in the drying chamber 25 can be reduced, and the slurry film 3 applied to a predetermined portion of the gas sensor element 1 can be dried in a short time.
(b) Since the drying oven 11 is formed in a hollow box shape, a recess 27 is provided in the upper part thereof, and the surplus space of the drying chamber 25 is filled with a heat insulating material 24, the space of the drying chamber 25 is It is also possible to improve the thermal efficiency by minimizing it.

(c) When the gas sensor element 1 is carried out, the door member 23 opens the work entrance 28, and immediately after that, the shutter 30 is closed to seal the drying chamber 25. As shown in FIG. When the gas sensor element 1 is carried in, the shutter 30 opens the drying chamber 25 just before the door member 23 closes the drying chamber 25 . Therefore, the time during which the drying chamber 25 is open can be shortened, and the room temperature can be kept constant.
(d) Since the door member 23 is attached to the elevating plate 21 and permanently attached to the loader 12, the gas sensor element 1 can be attached to and detached from the setter 4 at the standby position of the loader 12 without having to transport the setter 4 to another location. , the time required for workpiece replacement can be shortened.

(e) Since the rectifying members 35 and 37 on the inlet side and the outlet side are connected in series with the drying chamber 25, the flow of the hot air HW in the drying chamber 25 is less likely to be disturbed.
(f) Since a plurality of rectifying plates 41 are arranged side by side in a broom shape on the rectifying members 35 and 37 on the inlet and outlet sides, the hot air HW flows orderly in the arrangement direction of the gas sensor elements 1 and evenly spreads over the plurality of gas sensor elements 1 . hit.
(g) Therefore, the dried state of the slurry film 3 is less likely to vary, and the inside of the gas sensor element 1 is evenly heated. can suppress the occurrence of

(h) By adjusting the opening areas of the hot air inlet 33 and the hot air outlet 34 with the adjustment plates 36 and 38, the flow velocity of the hot air passing through the drying chamber 25 is changed, so that drying is performed according to the state of the slurry S in the dipping step. You can easily adjust the time.
(i) Since the blower mechanism 13 is constructed such that the blower 14 and the heater 15 are close to the hot air inlet 33 of the drying furnace 11, the amount of heat radiation to the surrounding environment is reduced.
(j) Since the exhaust air from the hot air outlet 34 of the drying furnace 11 is circulated through the circulation pipe 16 to the inlet of the blower 14, the exhaust heat of the drying furnace 11 can be recycled and the heating time of the drying chamber 25 can be shortened.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and as exemplified below, the shape and configuration of each part can be changed as appropriate without departing from the scope of the invention.

(1) In the embodiment shown in FIG. 11, the workpiece entrance 28 of the drying furnace 11 is covered with a shielding plate 46 from the drying chamber 25 side, and the shielding plate 46 is formed with a plurality of through holes 47 . When the door member 23 closes the workpiece entrance 28, the leg portion 102 of the gas sensor element 1 is inserted into the through hole 47, and the slurry film 3 is dried with only the leg portion 102 exposed in the drying chamber 25. be done. When the door member 23 is opened, the shielding plate 46 covers the workpiece entrance 28 until the shutter 30 is closed to prevent cold air from entering the drying chamber 25 .

(2) In the embodiment shown in FIG. 12, a plurality of air passages (hot air passages) are formed by broom-shaped straightening vanes 41 in the straightening members 35 on the inlet side and the outlet side (only the inlet side is shown). Adjusting plates 361 to 366 for adjusting the size of 33 are formed separately for each air passage. Therefore, by individually adjusting the positions of the adjustment plates 361 to 366, the flow velocity of the hot air passing through the hot air inlet 33 and the hot air outlet 34 can be finely adjusted for each air path.

(3) In the embodiment shown in FIG. 13, the heat insulating material 24 in the drying chamber 25 is provided with an uneven portion 241 having a shape following the arrangement of the gas sensor elements 1 . By providing the uneven portion 241 , the heat insulating material 24 fills the excess gap between the adjacent leg portions 102 to allow the hot air HW to spread over the entire circumference of the slurry film 3 . As a result, moisture contained in the interior of the slurry film 3 and the gas sensor element 1 can be removed in a short period of time, and the drying efficiency can be enhanced.

(4) In each of the above embodiments, the gas sensor element 1 was used as an example of a workpiece, but in other embodiments, the drying apparatus and drying method of the present invention can be applied to various workpieces having a slurry film applied to a predetermined portion. is also possible.

DESCRIPTION OF SYMBOLS 1... Gas sensor element (work), 3... Slurry film, 4... Setter,
DESCRIPTION OF SYMBOLS 10... Drying apparatus, 11... Drying furnace, 13... Ventilation mechanism, 23... Door member,
25... Drying chamber, 28... Work entrance, 30... Shutter.

Claims (6)

a setter (4) for supporting a plurality of works (1) coated with a slurry film (3) at predetermined sites;
a drying furnace (11) having a workpiece entrance (28) and a drying chamber (25);
a door member (23) that openably and closably covers the work entrance;
a blowing mechanism (13) for blowing hot air (HW) into the drying chamber when the door member closes the work entrance;
The setter is attached to the door member, and the door member arranges the predetermined portion of the work inside the drying chamber while the setter is positioned outside the drying chamber when the work entrance is closed. configured as
The drying apparatus (10) comprises a shutter (30) that closes the work entrance instead of the door member when the door member opens the work entrance. The drying oven includes a shielding plate (46) that shields the work inlet/outlet from the drying chamber side, and the shielding plate is formed with a plurality of through holes (47) through which the predetermined portions of the work are inserted and removed. The drying apparatus of claim 1, wherein the 2. The blowing mechanism includes a blower (14) for blowing hot air, a heater (15) for heating the hot air, and a circulation pipe (16) for passing the hot air through the drying chamber and returning it to the blower. Or the drying apparatus according to 2 . An inlet-side straightening member (35) for dispersing hot air and supplying it to the drying chamber is provided at the hot air inlet (33) of the drying furnace,
An outlet-side straightening member (37) for collecting hot air and discharging it from the drying chamber is provided at the hot air outlet (34) of the drying furnace,
The dryer according to any one of claims 1 to 3 , wherein a plurality of parallel straightening vanes (41) are provided in the inlet side straightening member and the exhaust side straightening member so as to extend in the blowing direction of the hot air. Device. 5. The drying apparatus according to claim 4 , wherein the drying furnace is provided with adjustment plates (36, 38) for separately adjusting opening areas of the hot air inlet and the hot air outlet. A step (S1) of supporting a plurality of works (1) coated with a slurry film (3) on predetermined portions on a setter (4);
A step (S3) of opening the shutter (30) to open the work entrance (28) of the drying furnace (11);
a step (S4) of closing the door member (23) to which the setter is attached, closing the work entrance (28), and carrying the setter into the drying chamber (25) of the drying oven;
a step of passing hot air through the drying chamber to dry the predetermined portion of the work for a predetermined time (S5);
a step (S6) of opening the door member after the lapse of the predetermined time and carrying out the setter from the drying chamber;
a step of closing the shutter to close the work entrance (S7);
A step (S8) of taking out the work from the setter,
A drying method, wherein, in the step of carrying the work into the drying chamber, the predetermined portion of the work is arranged in the drying chamber while the setter is positioned outside the drying chamber.

Images