JPS6134061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a drying device for drying a sheet-like object to be dried, such as a veneer veneer.
In particular, the present invention relates to an apparatus for drying an object to be dried by blowing high-temperature hot air under pressure.

Long or short sheet-like veneers cut from logs using rotary lace or the like are sequentially carried into a drying device, dried to a predetermined moisture content, and then carried out. As such a drying device, for example, as described in Japanese Utility Model Publication No. 48-22778, drying units having a function of supplying and circulating high-temperature hot air are connected in tandem in the required number of stages.
Often used is a system in which high-temperature hot air is blown from jet boxes placed on both the top and bottom of the veneer veneer brought in via an entrance conveyor, while the veneer is conveyed while being held between endless wire mesh belts, etc. However, in such drying equipment, there was a problem in that the presence of a wire mesh belt between the jet box nozzle and the veneer veneer weakened the blowing force of the hot air. In addition, in this drying device, the veneer veneer is compressed by multiple sets of rollers to smooth the veneer, but these rollers are heated by hot air after heating the veneer veneer discharged from the jet box. However, since the veneer veneer is compressed through a wire mesh belt, the veneer veneer cannot be expected to be smoothed by the ironing effect. Furthermore, in this type of drying apparatus, rolls for conveying the object to be dried and jet boxes are usually arranged alternately, so that it is difficult to increase drying efficiency by disposing only a large number of jet boxes.

Furthermore, Japanese Utility Model Application Publication No. 52-237 discloses a drying device for a wet copying system in which a rotating roll with a built-in heater and numerous ventilation holes on its circumference is hung horizontally in a drying chamber. There is. In this drying device, photosensitive paper is sucked through a number of ventilation holes provided on a rotating roll, and the photosensitive paper is heated by heat transfer from the rotating roll and from exhaust holes in piping placed on the rotating roll. It is done using hot air. However, with this type of drying equipment, the photosensitive paper comes into contact with only one side of the rotating roll equipped with a heater, so the ironing effect for smoothing the photosensitive paper is insufficient, and since piping is used to exhaust hot air, There is also the problem that the space factor is not good, and pressure loss and heat loss occur, reducing hot air heating efficiency.

Furthermore, Japanese Patent No. 180612 discloses a device in which a veneer veneer is conveyed by a pair of rotating rolls having ventilation holes on the circumference, and dry hot air can be ejected from the ventilation holes. However, this drying device has the disadvantage that only hot air blown out from the vents facing the veneer veneer can be used, so the drying efficiency with hot air is extremely low.

The present invention was made in order to eliminate the above-mentioned disadvantages in conventional devices, and an object of the present invention is to provide a drying device that can obtain an ironing effect due to direct heat transfer using high-temperature rolls and high drying efficiency due to hot air. It is something to do.

The object of the present invention is to (a) provide an upper roll and a lower roll each having a large number of hot air blowing holes on their circumferential surfaces, a portion of the upper roll and the lower roll that contact a sheet-like object to be dried that is continuously transported; (b) a drying chamber which covers the entire set of rolls; and (c) comprising a hot air supply source and a blower, the blower presses the hot air supplied from the hot air supply source into the set of rolls, and at least a portion of the hot air is blown into the drying chamber from the hot air injection holes of the set of rolls. This is realized by a drying device comprising a hot air circulation system that presses hot air newly supplied from the hot air supply source into the assembled rolls again using a blower.

That is, according to the present invention, moisture in the veneer veneer is rapidly evaporated due to direct heat transfer due to the ironing effect of the upper roll and lower roll of the set of rolls in (a), and in this state, pressure is applied to these rolls. A veneer veneer with a smooth surface is obtained, and at the same time, it is heated by the hot air from the nozzle opening near the veneer veneer in the nozzle box, which is supplied by the nozzle box in (a) and the hot air circulation system in (c). Moreover, since the evaporated water is immediately blown away by hot air, high drying efficiency is achieved.

The invention will now be described in detail with reference to the illustrated embodiments.

Figure 1 shows three drying units 1 connected in tandem to dry three veneer veneers V, each marked with an arrow A.
This shows an example of drying while conveying in the direction, and each drying unit 1 has three stages and four rows of conveying rolls 2, 3.
Nozzle boxes 4 and 5 are provided to cover these transport rolls, and as shown in FIG. 2, a hot air supply device 6, a filter 7, and a hot air circulation device 8 are also installed.

As the hot air supply device 6, a nozzle 6a is used that blows out high-temperature combustion gas obtained by burning liquid or gaseous fuel or wood chips, etc.
After the hot air blown out from this passes through the filter 7, it is pressurized by the blower 8a of the hot air circulation device 8.
As shown by arrows in FIG. 2, the hot air circulates through the drying unit 1 through the conveyor rolls 2 and 3, and part of it is discharged to the outside via the damper 9, and the remaining part is newly supplied from the hot air supply device 6. The hot air is again press-fitted into each of the transport rolls 2 and 3 and circulated within the drying unit 1.

Conveyance rolls 2, 3 and nozzle boxes 4, 5
The details are as shown in FIGS. 3 and 4.
That is, each of the transport rolls 2, 3 has a cylindrical part 21, 31 having a large number of hot air blowing holes 20, 30 on the circumferential surface, and shafts 22a, 22b, 32a fixed to both ends of the cylindrical part 21, 31.
32b, bearings 23a, 23b, 33
It is rotatably supported by a and 33b. Hollow shafts are used as the shafts 22a, 32a, and hot air is supplied to the cylindrical portions 21, 31 through these hollow shafts. The shafts 22b, 32b are solid shafts and are communicated by gears 24,34. Further, as the bearings 23a and 23b, U-shaped bearings lined with a heat-resistant anti-friction material such as graphite are used, so that the upper conveying roll 2 can move up and down relative to the lower conveying roll 3. ing. A chain wheel 35 fixed to the shaft 32a is connected to a rotational drive mechanism (not shown).

Nozzle boxes 4 and 5 are conveyor rolls 2 and 3, respectively.
The shaft 22 is arranged so as to cover the cylindrical parts 21 and 31 of the
The penetrating portions of a, 22b, 32a, and 32b are slidably sealed via heat-resistant anti-friction materials 40 and 50. These nozzle boxes 4, 5 are open at the portions facing the veneer veneer V, and the cylindrical portions 21, 31 protruding therefrom directly touch the surface of the veneer veneer V and clamp it. Therefore, the hollow shaft 22
A part of the hot air sent into the cylindrical parts 21, 31 through the hot air blowing holes 20, 32a is blown directly onto the surface of the veneer veneer V from the hot air blowing holes 20, 30, and the remaining part is once sent from the hot air blowing holes 20, 30 to the nozzle. After the jet flows into the boxes 4 and 5, slit-shaped nozzle parts 41 and 51 are formed between the opening and the cylindrical parts 21 and 31.
is sprayed onto the surface of the veneer V.

In the apparatus of the embodiment configured as described above, when the lower transport roll 3 is rotated by the rotation drive mechanism connected to the chain wheel 35, the movement is caused by the shaft 32.
b, 22b and the gears 34, 24 to the upper conveying roll 2, and therefore both rolls rotate in opposite directions to apply a conveying force to the sandwiched veneer veneer V. In this case, since the upper conveyor roll 2 is vertically movable by U-shaped bearings 23a and 23b, it moves up and down according to the thickness of the veneer veneer V passing through, and the pressing force due to its own weight is applied to the veneer veneer V. Add to. These conveyor rolls 2, 3 have hollow shafts 22a,
Since it is heated to a high temperature by the hot air sent through 32a, the veneer veneer V, which is clamped by these rolls with a predetermined pressing force, undergoes an ironing effect under the coexistence of heat and pressure, and is directly ironed. In addition to exhibiting high drying efficiency through heat transfer, the surface of the veneer is modified to have smooth properties and is prevented from curling. At that time, the hot air blowing holes 20, 30 of the cylindrical parts 21, 31
hot air directly blown onto the surface of the veneer veneer V and the cylindrical parts 21, 31 and nozzle boxes 4, 5.
Slit-shaped nozzle portions 41 and 5 formed between
The drying of the veneer is further accelerated by the hot air blown out from the veneer.

In addition, in the above explanation, three drying units equipped with three stages and four rows of conveyor rolls are connected in tandem.
Although an example has been described in which two veneer veneers are dried in parallel, the present invention is not limited to this, and it is of course possible to increase or decrease the number of stages, sets, or bases. As shown in the figure, with the help of spring belts 10a to 10f, it is also possible to dry a single veneer sheet while conveying it along a conveying path that curves like a hairpin as shown by the arrow.

Further, as illustrated in FIG. 6, seals 26 and 36 made of a heat-resistant and anti-friction material are used to connect the openings of the nozzle boxes 4 and 5 and the cylindrical portions 21 and 31 of the transport rolls 2 and 3 protruding therefrom. It may be sealed so that hot air is blown directly from the cylindrical parts 21 and 31 onto the surface of the veneer veneer V.

Furthermore, in the above embodiments, an example was explained in which the device of the present invention is applied to a drying device for plywood veneers, but the device of the present invention is applicable not only to a device for drying veneer veneers, but also to gypsum boards, laminate boards, and other sheet-like drying objects. It can also be used as a drying device.

In the above embodiments, the drying heat source is based on direct combustion of liquid or gaseous fuel, wood chips, etc., but the hot air supply device 6 may be replaced with a heat exchanger using steam or other heat medium, for example. I can do it.

As explained above, according to the drying apparatus of the present invention, a veneer veneer board with a smooth surface can be obtained by the ironing effect of the set of rolls, and it is possible to obtain a veneer veneer with a smooth surface by the ironing effect of the set of rolls. High drying efficiency is achieved by heating the atmosphere in the drying chamber.

[Brief explanation of the drawing]

FIG. 1 is a conceptual side view showing an embodiment of the apparatus of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a longitudinal sectional view showing details of the conveyance roll and nozzle box used in the apparatus of the invention, and FIG. 4 is a cross-sectional view thereof, FIG. 5 is a conceptual side view showing another embodiment of the device of the present invention, and FIG. 6 is a cross-sectional view showing another embodiment of the conveyor roll and nozzle box used in the device of the present invention. It is a front view. 1... Drying unit, 2, 3... Conveyance roll,
4, 5...Nozzle box, 6...Hot air supply device, 7...Filter, 8...Hot air circulation device, 2
0, 30...Hot air outlet, 21, 31...Cylindrical part, 22a, 22b, 32a, 32b...Shaft, 2
3a, 23b, 33a, 33b...bearing, 26,
36... Seal, 40, 50... Heat resistant anti-friction material, 4
1,51...Nozzle part, V...Plywood veneer.

Claims (1)

[Scope of Claims] 1 (a) An upper roll and a lower roll each having a large number of hot air injection holes on their circumferential surfaces, and a portion of the upper roll and lower roll that comes into contact with a sheet-like object to be dried that is continuously transported. and a nozzle box that covers except for the vicinity thereof, and a plurality of set rolls arranged in order along the path so as to pinch the object to be dried from above and below, and (b) covering the entire set of rolls. a drying chamber; (c) comprising a hot air supply source and a blower, the hot air supplied from the hot air supply source is forced into the set of rolls by the blower, and the hot air is blown into the drying chamber from the hot air injection hole of the set of rolls; A drying device comprising: a hot air circulation system in which at least a portion of the hot air, together with the hot air newly supplied from the hot air supply source, is forced into the set of rolls again by a blower.