JPS6134062B2 - - 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 veneer veneers cut from raw wood logs using a 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 the 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 a drying device, there was a problem that the blowing force of the hot air was weakened due to the presence of a wire mesh belt between the nozzle of the jet box and the veneer veneer. In addition, in this drying device, the veneer veneer is compressed by multiple sets of rollers to make it smooth, 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 and jet boxes for conveying objects to be dried are usually arranged alternately, so it is difficult to increase drying efficiency by disposing only a large number of jet boxes.

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.

An object of the present invention is to provide at least a pair of upper rolls and lower rolls that are arranged to pinch a sheet-like dry object that is continuously conveyed from above and below;
A nozzle box that covers these upper rolls and lower rolls so that the portions of these rolls that come into contact with the object to be dried are exposed and slits are formed on both sides thereof, and a hot air supply that supplies hot air to the nozzle box. This is achieved by a drying device characterized by comprising a source.

In other words, according to the present invention, moisture in the veneer veneer is rapidly evaporated by direct heat transfer due to the ironing effect of the upper roll and the lower roll, and in this state, the moisture in the veneer veneer is pressurized by these rolls to form a veneer veneer with a smooth surface. At the same time, it is heated by the hot air from the slit that opens near the veneer veneer of the nozzle box, and the evaporated water is immediately blown away by the hot air, achieving high drying efficiency.

The present invention will be explained in detail below 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 the arrow in Fig. 2, the nozzle box 4,
5 and circulates within the drying unit 1, a part of which is discharged to the outside through a damper 9, and the remainder is sent into the nozzle boxes 4 and 5 again together with the hot air newly supplied from the hot air supply device 6. Drying unit 1
circulate within.

Conveyance rolls 2, 3 and nozzle boxes 4, 5
The details are as shown in FIGS. 3 and 4.
That is, each transport roll 2, 3 has a cylindrical part 21, 31 and a shaft 22a, 22b, 32 fixed to both ends thereof.
bearings 23a and 23b, respectively.
It is rotatably supported by b, 33a, and 33b. The shafts 22b and 32b are connected by gears 24 and 34. Further, as the bearings 23a and 23b, U bearings lined with a heat-resistant anti-friction material such as graphite are used, and therefore, the upper transport roll 2 can move up and down relative to the lower transport roll 3. has been done. Chain wheel 3 fixed to shaft 32a
5 is connected to a rotational drive mechanism (not shown).

Nozzle boxes 4 and 5 are conveyor rolls 2 and 3, respectively.
It is arranged so as to cover the cylindrical parts 21 and 31 of the shaft 2.
The penetrating portions 2a, 22b, 32a, and 32b are slidably sealed via heat-resistant and antifriction materials 40 and 50. These nozzle boxes 4 and 5 have hot air inlets 41 and 51 as well as openings at the portion facing the veneer veneer V, and a cylindrical portion 2 protruding from there.
1 and 31 directly contact the surface of the veneer veneer V and clamp it. Further, slit-shaped hot air jetting nozzles 42, 52 are formed between the openings of the nozzle boxes 4, 5 and the cylindrical portions 21, 31. Therefore, the hot air sent into the nozzle boxes 4, 5 through the hot air inlets 41, 51 contacts and heats the cylindrical portions 21, 31 of the conveyor rolls 2, 3, and then passes through the hot air jetting nozzles 42, 52 directly onto the surface of the veneer 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 3.
The force is transmitted to the upper conveying roll 2 via 1b, 22b and the gears 34, 24, and therefore both rolls rotate in opposite directions to apply conveying force to the sandwiched veneer veneer V. In this case, the upper conveyor roll 2 is
Since it is movable up and down by shaped bearings 23a and 23b, it moves up and down according to the thickness of the veneer veneer V passing through it, and applies a pressing force to the veneer veneer V due to its own weight. These conveyor rolls are heated to a high temperature by the hot air flowing through the nozzle boxes 4 and 5, so the veneer veneer V, which is clamped with a predetermined pressing force by these rolls, is heated under the coexistence of heat and pressure. Due to the ironing effect, it exhibits high drying efficiency due to direct heat transfer, and the surface of the veneer is modified to be smooth and curl-free. At this time, the drying of the veneer is further promoted by the hot air ejected from the hot air ejection nozzles 42, 52.

Further, as illustrated in FIG. 6, the hot air jetting nozzles 42 and 52 of the nozzle boxes 4 and 5 and the conveyance rolls 2 and 3 protruding from the nozzle boxes 4 and 5 are appropriately closed with a heat-resistant anti-friction material, etc. A large number of hot air jet holes 0 are opened on the circumferential surfaces of the cylindrical parts of the nozzle boxes 4 and 5, and the hot air supplied to the nozzle boxes 4 and 5 is transferred to the conveyor rolls 2 and 3.
The hot air may be sprayed onto the veneer veneer V through the hot air blowing holes 0 of No. 3.

In the above explanation, an example was explained in which three drying units equipped with three stages and four rows of transport rolls are connected in tandem to dry three veneer veneers in parallel, but the present invention is not limited to this. It goes without saying that the number of stages, columns, or cardinal numbers can be increased or decreased, and as shown in FIG.
With the help of spring belts 10a to 10f, it is also possible to dry a single veneer sheet while being conveyed along a conveyance path that curves like a hairpin as shown by the arrow.

Furthermore, in the above embodiments, an example in which the device of the present invention is applied to a drying device for plywood veneer was explained, but the device of the present invention can be applied not only to a device for drying veneer veneer, but also to gypsum boards, laminate boards, and other sheet-like objects to be dried. It can also be used as a drying device. In this case, depending on the type of the object to be dried or the purpose of drying, it is also possible to use the upper roll and the lower roll by installing them in an open chamber without installing them in the drying chamber.

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. You can also do it.

As explained above, according to the drying device of the present invention, a veneer veneer with a smooth surface can be obtained due to the ironing effect of the upper roll and lower roll, and high drying efficiency is achieved due to the direct heating by these rolls and the nozzle box. be done.

[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 cross-sectional view thereof, FIG. 3 is a longitudinal cross-sectional view showing details of the conveyance roll and nozzle box used in the apparatus of the present invention, 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
1, 31... Cylindrical part, 22a, 22b, 32a,
32b...shaft, 23a, 23b, 33a, 33b
...Bearing, 40,50 ...Heat-resistant anti-friction material, 42,5
2...Nozzle for blowing hot air, V...Plywood veneer.

Claims (1)

[Scope of Claims] 1. At least a pair of upper rolls and lower rolls arranged to pinch a sheet-like dry object that is continuously transported from above and below, and these upper rolls and lower rolls, respectively. A drying method characterized by comprising a nozzle box that covers the roll so that the part that contacts the object to be dried is exposed and slits are formed on both sides of the nozzle box, and a hot air supply source that supplies hot air to the nozzle box. Device. 2. The drying device according to claim 1, wherein the upper roll and the lower roll are installed in a drying chamber having a hot air circulation system. 3 A hot air supply source and a blower are installed in the drying chamber, and the hot air supplied from the hot air supply source into the drying chamber is forced into the nozzle box by the blower and is blown out from the slits between the upper and lower rolls and the nozzle box. 3. The drying device according to claim 2, wherein at least a part of the hot air is sent into the nozzle box again by the blower together with hot air newly supplied from the hot air supply source. 4. The drying apparatus according to any one of claims 1 to 3, wherein the object to be dried is a veneer veneer. 5. The drying apparatus according to any one of claims 1 to 4, wherein the upper roll and the lower roll are installed in a plurality of rows along the transport path of the object to be dried.