JPH04190084A - Airflow circulating type drying device - Google Patents

Abstract

PURPOSE:To permit the drying work of a material to be dried without leaking smell into atmosphere by a method wherein the smell, contained in vapor gas, is conducted to flow from the main body of a dryer into a circulating route communicated with the main body of the dryer again through a condenser and a heat exchanger. CONSTITUTION:A material to be dried 8 is thrown into the main body 1 of a dryer and a rotating shaft 27 is turned whereby the material to be dried is biased toward the inner wall surface of the main body 1 of the dryer by a centrifugal force generated by rotation R while being guided and moved upward by a vertical screw rotary vane 28. Then, moisture contained in the material to be dried 8 is evaporated by heat transferred from a heating medium 15 in a heating medium jacket 14 provided on the outside of an inner wall surface. Vapor gas 9 from the material to be dried 8 is introduced into a condenser 3 through a vapor gas sending pipe 2 communicated with the main body 1 of the dryer and is cooled and condensed by said condenser 3 whereby gas 10 is separated from liquid. Thereafter, the liquid is guided to the outside of the condenser 3 as drain 11 while the gas 10 is guided into a heat exchanger 6 through a gas sending pipe 4 communicating the condenser 3 with a heat exchanger 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an air circulation device, and more specifically, it improves the drying efficiency of objects to be dried and also treats odors caused by the evaporation of moisture contained in objects to be dried. The present invention relates to a device for drying objects to be dried without using special equipment.

[Prior Art] As is well known, drying of highly water-containing materials such as food waste such as bean curd, fertilizer, feed, or industrial waste is often carried out. In the past, drying devices such as paddle dryers were used. However, the above-mentioned drying apparatuses have drawbacks in that there are certain limits to the efficiency of water evaporation, that is, drying efficiency, and that they are not suitable for all types of materials to be dried.

Therefore, the present applicant first developed a dryer main body, a rotating shaft disposed inside the dryer main body along the direction of gravity, a vertical spiral rotating blade spirally arranged along the rotating shaft, and a dryer We propose a technique in which a heating medium can be supplied to the outside of the dryer body or into the rotating shaft, and after the material to be dried is put into the dryer main body, the rotating shaft is rotated to dry the material. Ta.

More specifically, after the material to be dried is put into the dryer main body, it is pressed against the heat transfer surface formed on the inner wall surface of the dryer main body by the centrifugal force caused by the rotation of the rotating shaft and the vertical spiral rotating blade. It will be done. Then, by being pressed, the moisture in the dried material is evaporated. The material to be dried whose moisture has been evaporated on the vertical spiral rotary blade becomes lighter in mass and replaces the material to be dried behind it.

In this way, we proposed a technology in which the material to be dried is sequentially pressed against the heat transfer surface by the centrifugal force accompanying the rotation of the vertical spiral rotary vane and dried.

[Problems to be Solved by the Invention] According to the above-mentioned prior art, it is true that the drying efficiency of the material to be dried is high, and it has the advantage of being suitable for various kinds of material to be dried. However, as a result of further investigation, the following It was found that there were some problems in some respects.

Specifically, in order to use this advantageous dryer, if the odor contained in the water evaporated from the material to be dried is not treated using a separate odor treatment device, there is a risk of environmental pollution. There has been a need for a technique for treating the odor contained in the evaporated moisture without using a special odor treatment device.

In addition, in the process of pressing the highly water-containing material to be dried against the heat transfer surface by the centrifugal force caused by the rotation of the vertical spiral rotary vane and thereby evaporating the moisture, certain types of problems may occur if the surface of the material to be dried is not quickly dried first. In the case of objects to be dried, before they are brought to the heat transfer surface and dried, they stick together,
It may end up shaped like a dumpling. As a result, the surface area of the material to be dried becomes smaller than its volume, resulting in a decrease in drying efficiency.

Furthermore, due to the centrifugal force accompanying the rotation of the vertical spiral rotary blades, the material to be dried is successively pressed against the heat transfer surface and moisture evaporates, but the steam and heat remain in the space within the dryer main body and between the material to be dried. It was very overwhelming. As a result, if the temperature inside the dryer body increases, and the amount of heat per unit time from the heating medium transmitted to the heat transfer surface inside the dryer body is constant, the temperature inside the dryer body increases. The difference between the temperature of the heat transferred from the heating medium to the heat transfer surface becomes smaller. Therefore, the heat transfer coefficient becomes low, and the drying efficiency of the material to be dried cannot be improved.

Therefore, the purpose of the present invention is to uniformly dry each part of the material to be dried to increase the drying efficiency, as well as to dry various materials to be dried; The odor contained in the evaporated moisture is removed by the circulation method without the use of any special equipment, and the impact on the environment is reduced by preventing the odor from being released outside. By drying the surface of the object to be dried, the surface area of the object to be dried is kept large by suppressing the sticking of the objects to be dried, and by maintaining this state at all times, the contact area with the heat transfer surface is increased. In addition to increasing the drying efficiency, (1) In addition, by trapping heat inside the dryer body, the difference between the temperature inside the dryer body and the temperature of the heat from the heating medium becomes smaller, which reduces the heat from the heating medium. To prevent the heat transfer coefficient to the material to be dried from becoming small, and more specifically, by circulating the air inside the dryer body, the temperature inside the dryer body and the heat transfer from the heating medium to the heat transfer surface are prevented. It is an object of the present invention to provide a drying device that facilitates improving the drying efficiency of a material to be dried by increasing the temperature difference between the heating medium and the material to be dried and increasing the heat transfer coefficient of heat from the heating medium to the material to be dried.

[Means for Solving the Problems] In order to solve the above objects, the present invention has the following technical means.

That is, to explain using the reference numerals in the attached drawings corresponding to the embodiments, the present invention includes a dryer main body 1, a rotating shaft 27 disposed perpendicularly within the dryer main body 1 along the direction of gravity G; Vertical spiral rotary blade 2 spirally formed along the rotation axis 27
8, by putting the material to be dried 8 into the dryer main body l and rotating the rotating shaft 27 R, the material to be dried 8 is moved upward while being guided by the vertical spiral rotating blades 28. The centrifugal force caused by the rotation R causes the drying material 8 to be moved toward the inner wall surface of the dryer body 1, and heat is transferred from the heating medium 15 in the heating medium jacket 14 provided outside the inner wall surface to evaporate moisture in the material 8 to be dried. On the other hand, in a dryer in which the dried material 8 is taken out from below the dryer main body l, a condenser 3 is connected to the dryer main body l via an evaporative gas supply pipe 2. Furthermore, the condenser 3 is connected to a heat exchanger 6 via a gas supply pipe 4, and the heat exchanger 6 is connected to the lower part of the dryer body l via a heated gas supply pipe 7. This is an air circulation type drying device characterized by the following.

[Operation] Based on the above configuration, by putting the 5 objects to be dried 8 into the dryer main body L and rotating the rotating shaft 27 R, the objects 8 to be dried are guided by the vertical spiral rotating blades 28 and moved upward. At the same time, the centrifugal force caused by the rotation R draws it toward the inner wall surface of the dryer main body 1.

Then, heat is transferred from the heating medium 15 in the heating medium jacket 14 provided outside the inner wall surface, and the moisture contained in the material to be dried 8 evaporates.

Evaporated gas 9 from the material to be dried 8 is transferred to the dryer main body 1
The evaporated gas passes through an air supply pipe 2 connected to the evaporated gas and is guided to a condenser 3, where it is cooled and condensed and separated into gas 10 and liquid. Then, the liquid is led to the outside of the condenser 3 as a drain 11, while the gas lO is led to the heat exchanger 6 through the gas supply pipe 4 that communicates the muffler 3 and the heat exchanger 6.

The heat exchanger 6 gives heat to the guided gas 10 using steam, hot water, etc., and the gas IO that has received heat from the heat exchanger 6 is heated as a heated gas 12. The heated gas is guided into the dryer main body 1 from the lower part of the dryer main body 1 through a heated gas supply pipe 7 that communicates the heat exchanger 6 with the dryer main body 1.

That is, the evaporated gas 9 containing moisture released from the material to be dried 8 in the dryer main body 1 is condensed in the condenser 3, further heated in the heat exchanger 6, and returned to the dryer main body as heated gas 12. 1, it circulates.

As a result, the odor contained in the moisture evaporated from the material to be dried 8 in the dryer main body l is circulated without going outside the dryer, and there is no need to install a special odor treatment device. be.

Further, the heated gas 12 introduced as a jet from the lower part of the dryer main body 1 allows moisture on the surface of the object to be dried 8 to be dried relatively quickly.

Further, due to the reflux of air within the dryer main body 1, the heat within the dryer main body 1 is circulated, thereby preventing heat from accumulating within the dryer main body 1.

[Example] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a simplified illustration of the overall configuration of the air flow reflux type drying device of the present invention. A condenser 3 is connected via an air pipe 2, and the condenser 3 is connected to a heat exchanger 6 via a gas pipe 4 and a blower 5, and the heat exchanger 5 is connected to the heat exchanger 6 via a heated gas pipe 7. The opening communicates with the lower part of the dryer main body l.

The condenser 3 has a drying material 8 put into the dryer main body 1.
The evaporated gas 9 evaporated from the
The liquid thus led is led to the outside of the condenser 3 from the drain outlet 3a provided at the bottom of the condenser 3 as a drain 11', and the gas 10 is led to the outside of the condenser 3 through the gas supply pipe 4. and is led to the heat exchanger 6.

The heat exchanger 6 heats the introduced gas 10, and heats the gas 10 using steam 15b as a heating medium. Further, 6a is a steam inlet, and 6b is a steam outlet. In this example, steam 15b was used as the heating medium to heat the gas 10, but hot water may also be used.In addition, a hot air generating furnace is installed, and the hot air gas from the main hot air generating furnace is heated as described above. The gas 10 may be used as a heating medium by being guided to the heat exchanger 6, and the gas 10 heated by the heat exchanger 6 is passed as the heated gas 12 into the heated gas air pipe 7 that connects the heat exchanger 6 to the dryer main body l. It is guided through the dryer body l.

Further, a gas supply pipe 4 is connected from the condenser 3 to the heat exchanger 6.
A blower 5 provided in the middle is used to flow the evaporated gas 9, gas 10, and heated gas 12. And the temperature of each of the above gases 9.1O112 is
According to experiments, the temperature of the evaporated gas 9 is about 20°C, the temperature of the gas 10 is about 25°C, and the temperature of the heated gas 12 is about 60°C. still,
When a hot air generating furnace is used as the heat exchanger 6, the heated gas 1
2 can also be set at about 60°C to 600°C depending on the purpose.

Next, a description will be given focusing on the dryer main body l into which the material to be dried 8 is put. The dryer body 1 has a substantially cylindrical shape, and is installed on the ground B via legs 13 so as to be vertical. A heating medium jacket 14 is disposed around the outer periphery of the dryer main body l, and this heating medium jacket 1
Steam 15a (for example, OI
Steam with a vapor pressure of ~8 K g/c rn" is supplied from a boiler 16, and the inner wall surface of the dryer main body 1 is used as a heat transfer surface 19. The heating medium jacket 14 has the above-mentioned A pipe 17 from the boiler 16 is provided, and the steam 15 is connected to Ij at the bottom.
A drain outlet portion 20 is provided to which a pipe 40 for discharging the condensed drain 18 is connected. The dryer main body l is provided with an input port 21 above the heating medium jacket 14 for inputting the material 8 to be dried, and an input port cover for blocking the input port 21. 22 is attached by a lid holding member 23 so as to be openable and closable. Furthermore, an outlet 24 for taking out the dried material is provided at the lower part of the dryer main body 1, and an outlet M25 for blocking the outlet 24 is inserted into the outlet 24. ing. In the dryer main body l, a condenser 3 is provided to collect water that evaporates from the material to be dried 8.
An evaporated gas outlet 26 is provided for guiding the evaporated gas to the evaporated gas air pipe 2 .

Further, the dryer main body 1 is provided with a fluidizing means for fluidizing the material to be dried 8, and this fluidizing means has a rotating shaft 27 and a vertical spiral rotating blade 28. The rotating shaft 27 is disposed vertically along the gravity direction G, and the upper end portion 27a is the rotating shaft upper end through hole 2 on the upper surface of the dryer main body l.
9 and protrudes from the upper surface of the dryer main body l, and this protruding portion is held by a bearing 30 so as to be rotatable R. Therefore, a motor 31 is used as the driving force for rotating the rotating shaft 27, and this motor 31 is attached to the dryer main body 1 via a motor attachment piece 32. And this motor 3
A gear fixed to the first drive shaft 33 and a gear 34 fixed to the rotating shaft 27 are connected by a geared belt 35 so that the rotating shaft 27 is rotated R.

Further, the vertical spiral rotating blade 28 has a spiral shape along the rotating shaft 27, has a substantially semicircular cross section, and has an upper surface 28.
a is made flat, and a plurality of fixing arms 36
It is fixed to the rotating shaft 27 by. The distance between the vertical spiral rotating blade 28 and the heat transfer surface 19 of the dryer main body 1 is set so that the vertical spiral rotating blade 28 and the heat transfer surface 19 of the dryer main body 1 are close to each other to the extent that they do not touch each other, so that the vertical spiral rotating blade 28 can rotate R. Further, a portion between the inner peripheral side of the vertical spiral rotating blade 28 and the rotating shaft 27 is formed as a falling space A for the material to be dried 8 .

Next, focusing on the bottom part of the dryer main body l where the heated gas supply pipe 7 is connected, 7a is the part where the rotating shaft 27 is inserted and fixed so that the rotating shaft 27 can rotate freely. The rotation bearing of the heated gas supply pipe 7 is a part that protrudes from the lower surface of the dryer H main body by a predetermined height. The lower end portion 27b of the rotating shaft 27 is inserted into the lower end holding hole 38 of the rotating shaft provided at the lower part of the portion 7a, and the rotating shaft 27 has a rotating bearing. A heated gas guide section 39 formed in an umbrella shape is provided above 7a, and after the heated gas 12 that has passed through the heated gas air pipe 7 comes out from the heated gas air supply lower b, the heated gas guide section 39 is The direction of flow is changed by the section 39, and the heated gas is guided into the dryer main body l from the outlet 39a of the heated gas guide section.

Note that each part of the dryer main body 1, the rotating shaft 27, the vertical spiral rotating blade 28, etc. is constructed by appropriately welding a plurality of members, but the drawings are complicated in the drawing. In some parts, the parts are shown as being integrally formed to allow the walls to be separated.

With the above configuration, first, the input port cover 22 is opened and the material to be dried 8 is charged into the dryer main body l through the input port 21. Here, examples of the above-mentioned material to be dried 8 include okara,
Possible items include sludge, feed, fertilizer, industrial waste, or solid materials with high moisture content that require drying. The material to be dried 8 put into the dryer main body l accumulates on the lower surface inside the dryer main body l.Next, the steam 15a from the boiler 16 is transferred to the heating medium jacket 14 of the dryer main body l. The heat transfer surface 19 of the dryer main body 1 is heated by supplying the water.Next, the motor 31 rotates the vertical spiral rotary blade 28 together with the rotary shaft 27. Here, the vertical spiral rotating blade 28 in this example is as follows:
When viewed from above in the direction of gravity G, it is formed to rotate counterclockwise from above to below. Therefore, in this example, the vertical spiral rotating blade 28 is rotated counterclockwise when viewed from above. By the rotation R of the vertical spiral rotary vane 28, the object 8 to be dried rides on the upper surface 28a of the vertical spiral rotary vane 28 and is lifted up. To explain this rise in detail, when the vertical spiral rotary blade 28 rotates R, the object to be dried 8 exerts inertia to maintain its position with respect to the rotation R. Therefore, the object to be dried acts 8 slides on the upper surface 28a of the vertical spiral rotating blade 28. In other words, the upper surface 28a slides with respect to the object 8 to be dried, which is trying to maintain its position in the rotation R direction. Since the vertical spiral rotating blade 28 has a spiral shape, when viewed from the side,
The upper surface 28a is oblique with respect to the horizontal direction of gravity G. Therefore, the vertical spiral rotating blade 28
The rotation R causes the upper surface 28a to push up the object 8 to be dried.

Next, centrifugal force is generated on the material to be dried 8 due to the rotation R,
Due to this centrifugal force, the material to be dried 8 moves toward the outer periphery of the vertical spiral rotary blade 28 and comes into contact with the heat transfer surface 19 of the inner wall surface of the dryer main body 1. The moisture contained in the object 8 to be dried brought into contact with the heat transfer surface 19 is evaporated as evaporation gas 9 by the heat transferred from the heat transfer surface 19 . Looking at dry evaporation on the heat transfer surface 19 in more detail, if the moisture content of the material to be dried 8 is large, the mass is large, so first the material to be dried 8 with a large mass is drawn to the heat transfer surface 19 by centrifugal force and dried. Then, the object 8 to be dried behind it replaces and contacts the heat transfer surface 19, and in this way, all the objects 8 to be dried sequentially contact the heat transfer surface 19. Further, the material to be dried 8 is made to overflow from the upper part of the vertical spiral rotating blade 28, so that the falling space A on the inner peripheral side of the vertical spiral rotating blade 28 is
to fall. The material to be dried 8 accumulated in the lower part of the inside of the dryer main body l is removed by the lower vertical spiral rotary blade 28.
This causes it to rise upward.

That is, the object 8 to be dried in the dryer main body 1 is raised upward by the vertical spiral rotating blade 28, and the entire object 8 to be dried uniformly contacts the heat transfer surface 19, and then falls. It is dried by evaporating the water it contains while performing a circulating flow.

The evaporated gas 9 from the material to be dried 8 is guided from the evaporated gas outlet 26 through the evaporated gas supply pipe 2 to the condenser 3 via the upper space inside the dryer main body l.
It is cooled and contracted by #, and is separated into gas 10 and liquid. Then, the liquid is led to the outside of the condenser 3 as a drain 11 from the drain outlet 3a, while the gas lO is guided to the outside of the condenser 3 as a drain 11.
and is led to the heat exchanger 6. After the gas 10 is heated by the heat exchanger 6, it is guided as a heated gas 12 into the dryer main body l through the heated gas supply pipe 7.

In this example, the blower 5 is used to blow each gas at 9°1O112
It is used as a floating aid.

Further, in this example, steam 15a is used as a means for transmitting heat to the object to be dried 8 via the heat transfer surface 19, but other than this, for example, hot water or the like may be used.

As mentioned above, the material to be dried 8 put into the dryer main body l
is raised by the vertical spiral rotating blade 28,
Due to the centrifugal force caused by the rotation R, the objects 8 to be dried that are brought closer to the heat transfer surface 19 and in contact with the heat transfer surface 19 are sequentially replaced, and the objects 8 to be dried that have been raised by the vertical spiral rotating blades 28 fall down. By repeating the circulating flow of , rising again, it is easy to uniformly dry the material 8 to be dried.

Further, the evaporated gas 9 containing odor produced when drying the material to be dried 8 is guided to the condenser 3 and heat exchanger 6 connected to the dryer main body l, and then returned to the dryer main body as a heated gas 12. By configuring the circulation path leading to the drying object 8, it is possible to dry the object 8 to be dried without releasing the odor generated from the object 8 to the outside.

In addition, by spouting the heated gas 12 into the dryer main body 1 from the lower part of the dryer main body 1, when the material to be dried 8 is put into the dryer main body 1, the moisture content is still relatively high. The surface of the dried material 8 is dried to suppress sticking of the dried material 8 to each other. Thereby, the surface area of the material to be dried 8 becomes relatively large, and by constantly maintaining this state, it is easy to increase the contact area with the heat transfer surface 19.

Since the air circulates between the dryer main body 1, the condenser 3, and the heat exchanger 6, the air inside the dryer main body 1 also constantly circulates. This prevents the heat generated in the dryer main body l from being trapped, and when the amount of heat per unit time transmitted from the steam 15a to the heat transfer surface 19 is constant,
From the temperature inside the dryer main body 1 and the steam 15a to the heat transfer surface 19
This prevents the difference in temperature between the heat transmitted to the

Next, FIG. 4 shows the second embodiment, which is similar to the first embodiment.
The parts that are substantially the same as those in the first embodiment will be omitted, and only the different parts will be described. , In this embodiment, there are a plurality of dryer bodies l (three in this example).
Prepare the plurality of dryer bodies l in parallel and connect the condenser 3.
and connected to the heat exchanger 6. More specifically, the evaporated gas 9 from the material to be dried 8 introduced into each of the plurality of dryer bodies 1 joins in the evaporated gas air supply pipe 2 connected to each dryer body 1, and flows into the condenser 3. be guided. On the other hand, the heated gas 12 from the heat exchanger 6 passes through the heated gas supply pipes 12 connected to each dryer main body l, and branches off. ji number of dryer bodies l. This embodiment is effective when a large amount of material 8 to be dried is to be dried.

[Effects of the Invention] As detailed above, the air circulation drying device according to the present invention has the following effects:
A condenser is connected to the dryer body via an evaporative gas supply pipe,
Furthermore, the condenser is connected to a heat exchanger via a gas supply pipe, and the heat exchanger is configured to have an open communication with the lower part of the dryer main body via a heated gas supply pipe.
It has the following effects.

That is, when drying the material to be dried that has been put into the dryer main body, the odor contained in the evaporated gas is removed from the dryer main body through a circulation path that communicates with the dryer main body through a condenser and a heat exchanger. Since it only flows through the air, it is possible to dry the items to be dried without the need for special odor treatment equipment and without leaking odor into the outside air, minimizing the impact of odor on the environment. Easy to do.

In addition, by blowing out heated gas into the dryer main body, the surface of the drying material that still has a high water content when the material to be dried is put into the drying device main body is dried, thereby preventing the material from sticking to each other. suppress. As a result, the heat transfer surface and the object to be dried come into contact with each other in a state where the surface area of the object to be dried is relatively large, and the contact area can be easily made relatively large, thereby making it easier to increase the drying efficiency of the object to be dried.

Then, due to the circulation of air in the circulation path that communicates from the dryer main body through the #condenser and heat exchanger H to the dryer main body again, air circulation occurs within the dryer main body, and heat is generated inside the dryer main body. Prevent from becoming crowded. As a result, when the amount of heat transferred from the heating medium to the heat transfer surface per unit time is constant, by increasing the difference between the temperature inside the dryer body and the temperature of the heat transferred from the heating medium to the heat transfer surface, the heating It is possible to increase the heat transfer coefficient from the heat transfer surface through which the heat of the medium is transferred to the object to be dried, and it is easy to improve the drying efficiency of the object to be dried.

[Brief explanation of drawings]

The accompanying drawings show embodiments of the present invention, and FIGS. 1 to 3 are the first embodiment, and FIG. 1 is an overall view of the drying device;
Figure 2 is a diagram of the main body of the dryer, Figure 3 is a diagram showing the movement of the material to be dried and the flow of heated gas, and Figure 4 is the second embodiment, in which multiple dryer bodies are connected in parallel. It is a diagram of a state in which they are connected. The code in the drawing is l1. Dryer main body 2, evaporated gas air pipe 30. Condenser 4, 0. Gas pipe 61. , heat exchangers 7, 9 heated gas air pipes 801. Material to be dried 140. The heating medium jacket 15, the heating medium 27, the rotating shaft 28, the vertical spiral rotating blade G, . . . one rotation in the direction of gravity R9, respectively. Agent Patent attorney Ike 1) Hiroshi Figure 2 Figure 3 Procedural amendment written form) October 2, 1990 2 Title of invention Air circulation type drying device 3 Relationship to the case of the person making the amendment Patent applicant address 18-10 Nagata Sanno, Minami-ku, Yokohama Name Zenben Kisetsu 4 Agent 243 Address 1-21-12 Asahi-cho, Atsugi-shi, Kanagawa September 25, 1990 6 Subject of amendment

Claims (1)

[Claims] (1) From the dryer main body 1, a rotating shaft 27 disposed vertically in the dryer main body 1 along the gravity direction G, and a vertical spiral rotating blade 28 spirally formed along the rotating shaft 27. By putting the material 8 to be dried into the dryer main body 1 and rotating the rotating shaft 27, the material 8 to be dried is guided by the vertical spiral rotary blades 28 and moved upward while being rotated. Due to the centrifugal force associated with R, it is brought to the inner wall surface of the dryer main body 1, and heat is transferred from the heating medium 15 in the heating medium jacket 14 provided outside the inner wall surface, and the moisture in the material to be dried 8 is evaporated, On the other hand, in a dryer in which the dried material 8 is taken out from below the dryer main body 1: A condenser 3 is connected to the dryer main body 1 via an evaporative gas supply pipe 2, and further The condenser 3 is connected to a heat exchanger 6 via a gas supply pipe 4, and the heat exchanger 6 is connected to the bottom of the dryer main body 1 via a heated gas supply pipe 7. Air flow reflux type drying equipment.