Airflow dryer

Abstract

We propose an airflow dryer that can thoroughly dry the material to be dried while suppressing the discharge of the material or insufficiently dried powder or granular material. [Solution] The dryer body 2, which has an air intake port 35 at the top and a hot airflow generating means at the bottom, is divided into a recovery inner air area 9 drawn in from the air intake port 35 and a drying inner air area 8 where a swirling upward airflow is generated by the hot airflow generating means. The dryer body 2 is divided into a classification cover portion 42. The interior of the dryer body 2 is divided into a recovery inner air area 9 drawn in from the air intake port 35 and a drying inner air area 8 where a swirling upward airflow is generated by the hot airflow generating means. A classification cylinder portion 43 is formed by projecting downward from the center of the classification cover portion 42 and connecting the drying inner air area 8 and the recovery inner air area 9. A classification guide portion 44 is disposed inside the classification cylinder portion 43 and forms a classification gap 47 between itself and the inner circumferential surface of the classification cylinder portion 43. With this configuration, it is possible to suppress the inflow of the material to be dried or insufficiently dried powder into the recovery inner air area 9 and to allow it to remain in the drying inner air area 8.

Description

Technical Field

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[0001] The present invention relates to a pneumatic dryer for drying a material to be dried containing moisture with hot air.

Background Art

[0002] As a dryer for drying a material to be dried containing moisture with hot air, for example, the configuration of Patent Document 1 is known. Such a conventional configuration generates a swirling upward airflow by a heating gas in a cylindrical container having an internal space, and dries the material to be dried by the swirling upward airflow. The dried powder or granules rise along with the upward airflow and are discharged from a discharge pipe at the upper part of the cylindrical container. According to this configuration, the material to be dried having moisture can be dispersed and dried by the upward force and centrifugal force acting on the swirling upward airflow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above-described conventional configuration, since a heating gas is supplied to the cylindrical container to generate a swirling upward airflow, when the swirling upward airflow rises inside the cylindrical container, there is a possibility that the swirling upward airflow is disturbed by various factors. Specifically, depending on the properties (size, hardness, moisture content, etc.) and supply amount of the material to be dried, the swirling upward airflow may be disturbed, or the swirling upward airflow may be attenuated as it rises, resulting in such disturbance. In the above-described conventional configuration, means for newly supplying a heating gas in the middle part in the vertical direction of the cylindrical container to generate a swirling upward airflow is provided to suppress the attenuation of the swirling upward airflow. Therefore, since a large change occurs in the airflow at the boundary of this means, the airflow is likely to be disturbed.

[0005] On the other hand, within the internal space of the cylindrical container, centrifugal force is generated by the swirling updraft, and this centrifugal force creates negative pressure inside the swirling updraft (near the center of the internal space). Therefore, due to the turbulence of the aforementioned swirling updraft, if undried material to be dried or powders that are not sufficiently dried and dispersed enter the negative pressure area (hereinafter referred to as the negative pressure area), they will be discharged from the discharge pipe by suction. Thus, there was a problem in that undried material to be dried or powders that are not sufficiently dried and dispersed were mixed with sufficiently dried powders and discharged from the airflow dryer.

[0006] This invention proposes an airflow dryer that can thoroughly dry the material to be dried while suppressing the discharge of undried material or insufficiently dried powder or granular material. [Means for solving the problem]

[0007] The present invention relates to an airflow dryer comprising: a dryer body having a sealed drying internal air space inside and an intake port at the top that communicates with a predetermined intake means; a hot airflow generating means provided at the bottom of the dryer body that generates a swirling upward airflow in the drying internal air space using hot air supplied from a predetermined hot air supply means, and the swirling upward airflow generated in the drying internal air space dries the material to be dried introduced into the drying internal air space and discharges it from the intake port, wherein the airflow dryer comprises: a classification cover portion provided inside the dryer body that divides the interior into a recovery internal air space drawn in from the intake port and the drying internal air space below the recovery internal air space; a cylindrical classification cylinder portion formed projecting downward from the center of the classification cover portion and communicating the drying internal air space and the recovery internal air space; and a classification guide portion disposed inside the classification cylinder portion and forming an annular classification gap between itself and the inner circumferential surface of the classification cylinder portion. In this configuration of the present invention, the drying internal air area and the recovery internal air area are in communication via a classification gap.

[0008] In an airflow dryer configured to dry materials using a swirling updraft, the materials are dried (and dispersed) while swirling upwards in the drying chamber by the swirling updraft. The sufficiently dried granular material (hereinafter referred to as "dried granular material") moves to the central area of ​​the drying chamber, while the undried material or granular material that is not sufficiently dried and dispersed (hereinafter referred to as "insufficiently dried granular material") swirls around the periphery of the drying chamber (outside the central area) due to its own weight and the centrifugal force of the swirling updraft. As a result, the dried granular material that has moved to the central area of ​​the drying chamber passes through the classification gap and moves to the recovery chamber, where it is discharged from the intake port. On the other hand, undried material to be dried or insufficiently dried powders and granules rise by swirling around the periphery due to the centrifugal force. Even if they attempt to move towards the central area at the top of the drying airspace, this movement is suppressed by the classification cylinder, preventing them from moving into the recovery airspace. Furthermore, even if the material to be dried or insufficiently dried powders and granules move towards the central area below the classification cylinder due to turbulence in the swirling upward airflow in the drying airspace, they are less likely to pass through the classification gap, which has a smaller opening area than the classification cylinder, compared to dried powders and granules, thus preventing them from moving into the recovery airspace. Thus, the configuration of the present invention can prevent the material to be dried or insufficiently dried powders and granules from being discharged from the suction port via the recovery airspace, and can stably recover dried powders and granules from the suction port. In addition, since the material to be dried or insufficiently dried powders and granules can be retained in the drying airspace, they can be sufficiently dried by the swirling upward airflow and then moved to the recovery airspace after drying. Therefore, according to the configuration of the present invention, the material to be dried can be thoroughly dried, and the thoroughly dried powdered material can be stably recovered.

[0009] In the airflow dryer of the present invention described above, a configuration is proposed in which the classification guide section is equipped with a classification projection that has a circumferentially formed inclined surface that slopes inward with a downward gradient. In this configuration, the classification protrusion can preferably be conical, hemispherical, or polygonal pyramidal (square pyramidal or octagonal pyramidal). Among these, conical or hemispherical classification protrusions are particularly preferred.

[0010] In this configuration, the material to be dried or insufficiently dried powder or granules that enter the inside of the classification cylinder can be repelled by the inclined surface of the classification protrusion and returned to the drying airspace. As a result, they can be retained in the drying airspace and thoroughly dried by the swirling updraft. Here, in the dry airspace, a negative pressure zone is created inside the swirling updraft, as described above. In this negative pressure zone, the negative pressure increases towards the center, causing the dried granular material, material to be dried, and insufficiently dried granular material that enter the negative pressure zone to rise along the center of the negative pressure zone. Since the classification protrusion of this configuration is positioned directly above the center of this negative pressure zone, the material to be dried and insufficiently dried granular material come into contact with the classification protrusion and are repelled as described above. On the other hand, since the dried granular material is smaller in size (and lighter) than the material to be dried and insufficiently dried granular material, it is easier for it to move into the recovery airspace through the classification gap on the updraft.

[0011] Furthermore, because the cross-sectional area of ​​the inner airspace of the classification cylinder gradually decreases upwards due to the classification protrusions, the centrifugal force generated by the swirling airflow in this inner airspace increases as it moves upwards. This has the advantage of further improving the dispersibility and reduction of water content of the powder and granular material that enters the inner airspace of the classification cylinder.

[0012] In the airflow dryer of the present invention described above, the dryer body is substantially cylindrical with both upper and lower ends closed, and the hot airflow generating means is provided in a plurality on the lower side surface of the dryer body at predetermined intervals in the circumferential direction of the dryer body, and comprises a hot air inlet that allows hot air to flow into the drying air space in one circumferential direction along the tangential direction of the dryer body, and a chamber body disposed to cover the lower part of the dryer body where the hot air inlet is formed in a sealed manner, forming a supply air space around the lower part to which hot air is supplied to flow into the hot air inlet, and directly below the dryer body, having a supply port that allows hot air supplied from the hot air supply means to flow into the supply air space.

[0013] In this configuration, the relative positions (distance and relative orientation) of each of the multiple hot air inlets provided on the lower side of the dryer body and the supply port of the chamber body are approximately the same. This allows hot air to flow approximately equally from each hot air inlet into the drying chamber, and a stable swirling upward airflow can be generated in the drying chamber. This swirling upward airflow allows the material to be dried to swirl and rise more stably in the drying chamber, improving the drying efficiency (and dispersion efficiency) of the material to be dried, and thus further improving the effect of moving the dried powder and granules to the recovery chamber as described above.

[0014] Furthermore, since the lower part of the dryer body can be stably heated by the hot air supplied to the chamber's supply air area, the drying air area can be maintained at a high temperature, making it easier to dry the material being dried as it swirls in the swirling updraft. As a result, the drying efficiency of the material being dried by the airflow dryer can be dramatically improved.

[0015] In this configuration, it is preferable that the intake port is configured to draw in air from the recovery air area along the tangential direction of the dryer body such that the direction of rotation of the swirling airflow generated in the recovery air area by the intake means is the same as the direction of rotation of the swirling updraft generated in the drying air area. In this configuration, it is possible to suppress the attenuation caused by the swirling airflow in the recovery airspace and the swirling updraft airflow in the drying airspace interfering with each other. This improves the classification effect, which moves the dried powder into the recovery airspace through the classification gap, and also improves the discharge efficiency by allowing the powder that has flowed into the recovery airspace to be smoothly discharged from the intake port.

[0016] In the airflow dryer of the present invention described above, a configuration is proposed in which the dryer body is provided with an input cylinder portion that protrudes into the drying air space and has an input port at its tip for introducing the material to be dried into the drying air space, and the input port of the input cylinder portion is positioned to face the negative pressure area inside the swirling updraft generated in the drying air space.

[0017] In such a configuration, since the inlet of the charging cylinder portion is arranged to face the negative pressure region, it is possible to suppress the dried objects swirling in the inner drying airspace and inadequately dried powder particles from flowing into the inlet due to the centrifugal force of the swirling upward airflow and flowing backward inside the charging cylinder portion. In addition, it is also possible to suppress the hot air swirling in the inner drying airspace from flowing in through the inlet. From these facts, it is possible to stably charge the dried objects from the charging cylinder portion into the inner drying airspace.

[0018] Here, in this configuration, since the charging cylinder portion protrudes into the inner drying airspace, turbulence may occur in the swirling upward airflow due to the charging cylinder portion. When turbulence occurs in the swirling upward airflow, although the dried objects and inadequately dried powder particles that are subject to the centrifugal force of the swirling upward airflow may move to the central region (negative pressure region) of the inner drying airspace, in the present invention, as described above, it is possible to suppress these dried objects and inadequately dried powder particles from passing through the classification gap. Furthermore, it is possible to suppress the dried particles and inadequately dried powder particles from moving into the inner airspace of the classification cylinder portion by the classification cylinder portion. That is, this configuration can suppress the dried objects and inadequately dried powder particles from passing through the classification gap and being discharged even when turbulence occurs in the swirling upward airflow, and the above-described operational effects of the present invention, namely that these can be sufficiently dried, can be stably exhibited.

Effects of the Invention

[0019] According to the airflow dryer of the present invention, as described above, it is possible to sufficiently dry the dried objects charged into the inner drying airspace, and while suppressing the discharge of undried dried objects and inadequately dried powder particles, it is possible to stably recover the dried powder particles.

Brief Description of the Drawings

[0020] [Figure 1] It is a (A) side view and a (B) longitudinal sectional view showing the airflow dryer 1 of the present embodiment. [Figure 2] It is a cross-sectional view taken along the line X-X in FIG. 1. [Figure 3] In FIG. 1, it is a (A) cross-sectional view taken along the line Y-Y and a (B) cross-sectional view taken along the line Z-Z. [Figure 4]It is an enlarged view of the M-M portion in FIG. 1. [Figure 5] It is an enlarged view of the N-N portion in FIG. 1. [Figure 6] It is a perspective view showing a longitudinal section of the lower part of the dryer body 2. [Figure 7] It is a perspective view seen from above showing a longitudinal section of the upper part of the dryer body 2. [Figure 8] It is a perspective view seen from below showing a longitudinal section of the upper part of the dryer body 2. [Figure 9] It is an explanatory view showing a mode of drying an object to be dried by the airflow dryer 1. [Figure 10] It is a cross-sectional view showing an enlarged lower part of the dryer body 2 of another example.

Mode for Carrying Out the Invention

[0021] Examples embodying the present invention will be described using the accompanying drawings. The airflow dryer 1 of this embodiment is for drying and dispersing an object to be dried containing moisture. As shown in FIG. 1, it includes a cylindrical dryer body 2 with both upper and lower ends hermetically closed, and a chamber body 3 connected to the lower part of the dryer body 2.

[0022] This airflow dryer 1 constitutes a drying treatment system (not shown) for supplying the object to be dried and taking out the dried and dispersed powder particles. The drying treatment system includes the airflow dryer 1, a material supply means (not shown) for supplying the object to be dried to the airflow dryer 1, a hot air supply means (not shown) for supplying high-temperature hot air to the airflow dryer 1, a bag filter (not shown) for taking out the powder particles dried by the airflow dryer 1, and an intake means (not shown) for taking in air from the airflow dryer 1 through the bag filter. Here, as the hot air supply means, one including a blower and a hot air furnace for heating the air generated by the blower to a high temperature is applied. As the material supply means, a screw feeder is applied. As the intake means, an exhaust fan can be applied. Since these hot air supply means, material supply means, bag filter, and intake means can be those known in the art, details are omitted.

[0023] The dryer body 2 of the airflow dryer 1 comprises a cylindrical peripheral wall portion 5 arranged in an upright position, a disc-shaped top wall portion 6 that closes the upper end of the peripheral wall portion 5, and a disc-shaped bottom wall portion 7 that closes the lower end of the peripheral wall portion 5. The chamber body 3 is arranged to cover the lower part of the dryer body 2 in a sealed manner. The chamber body 3 comprises a cylindrical outer peripheral wall portion 11 having an inner and outer diameter larger than the outer diameter of the dryer body 2, an annular upper wall portion 12 that closes the upper end of the outer peripheral wall portion 11, and a substantially annular lower wall portion 13 that closes the lower end of the outer peripheral wall portion 11. The chamber body 3 is integrally connected to the dryer body 2 such that the outer peripheral wall portion 11 and the peripheral wall portion 5 of the dryer body 2 are located coaxially (in other words, the dryer body 2 and the chamber body 3 are arranged coaxially). Furthermore, a supply port 14 opening downwards is formed in the center of the lower wall portion 13 of the chamber body 3, and hot air flows into this supply port 14 from the hot air supply means. This chamber body 3 creates a supply air area 15 around the lower part of the dryer body 2, through which hot air is supplied via the supply port 14.

[0024] As shown in Figures 2, 4, and 6, a plurality of hot air nozzles 21 are provided at equal intervals in the circumferential direction along the tangential direction of the peripheral wall 5 of the dryer body 2, in the lower part covered by the chamber body 3. The hot air nozzles 21 have a hot air inlet 22 that connects the inside of the dryer body 2 to the supply air area 15, and is provided along the tangential direction. In this embodiment, the hot air inlet 22 opens into the supply air area 15 in a vertically elongated rectangular shape.

[0025] The aforementioned chamber body 3 and the multiple hot air nozzle sections 21 (hot air inlets 22) allow the hot air supplied from the hot air supply means to flow substantially evenly into each hot air nozzle section 21 via the supply air area 15. As the hot air flows out tangentially into the interior of the dryer body 2 through the hot air inlets 22 of each hot air nozzle section 21, a circumferentially swirling airflow is generated inside the dryer body 2 by the hot air flowing out from each hot air inlet 22. In this embodiment, a supply port 14 into which hot air flows upward into the supply air area 15 is provided in the horizontal center, and multiple hot air inlets 22 that open tangentially are provided at equal intervals in the circumferential direction. Therefore, the distance between the supply port 14 and each hot air inlet 22 is equal, and the relative orientation of each hot air inlet 22 with respect to the supply port 14 is equal. As a result, hot air with approximately the same flow velocity and flow rate can be introduced into the dryer body 2 from each hot air inlet 22, thereby stably generating the high-speed swirling airflow. Furthermore, in this embodiment, since the hot air inlet 22 is configured to open in a vertically elongated rectangular shape, hot air can be introduced into the dryer body 2 in a relatively long width in the vertical direction. This makes it possible to generate the swirling airflow even more stably and to efficiently heat the lower part of the peripheral wall 5 of the dryer body 2 with hot air, making it easier to maintain a high temperature at the lower part of the peripheral wall 5. In addition, since the area around the lower part of the peripheral wall 5 is covered by the supply air area 15, the lower part of the peripheral wall 5 can also be heated and maintained at a high temperature by the hot air supplied to the supply air area 15.

[0026] Hot air flows continuously into the dryer body 2 through the chamber 3 and the hot air nozzle 21, generating a swirling upward airflow along the inner circumferential surface of the dryer body 2. As shown in Figures 1 and 4, a negative pressure region 19 can be created in the central area inside the dryer body 2 due to the centrifugal force of the swirling upward airflow. In other words, in the internal air space of the dryer body 2 (the drying internal air space described later), the swirling upward airflow flows in the radially outer peripheral region 18, and the negative pressure region 19 is created radially inside the peripheral region 18.

[0027] Furthermore, as shown in Figures 4 and 6, the bottom wall 7 of the dryer body 2 is provided with a through-hole 16 that penetrates vertically through its center, and a hollow conical repelling section 25 that protrudes upward is positioned in the center of the bottom wall 7 to cover the through-hole 16. Hot air flows into the repelling section 25 through the through-hole 16, thereby heating the repelling section 25 and maintaining a high temperature.

[0028] As shown in Figures 1 and 4, the dryer body 2 is provided with an input cylinder 31 in the peripheral wall 5, above the chamber body 3, for introducing the material to be dried into the dryer body 2. This input cylinder 31 constitutes the screw feeder and penetrates the peripheral wall 5 from the outside, protruding into the dryer body 2. The input cylinder 31 is attached to the dryer body 2 such that the input opening 32 at the tip of the input cylinder 31 is close to the negative pressure area 19 inside the dryer body 2. By positioning the input opening 32 to face the negative pressure area 19, it is possible to prevent the material to be dried and the hot air from flowing back into the input cylinder 31 due to the centrifugal force of the swirling updraft.

[0029] On the other hand, as shown in Figure 1, a classification means 41 is provided inside the dryer body 2, and the internal air space is divided vertically by the classification means 41. The air space below the classification means 41 in the internal air space of the dryer body 2 is the drying internal air space 8 according to the present invention, and the air space above the classification means 41 is the recovery internal air space 9 according to the present invention. Below the classification means 41 in the dryer body 2, the chamber body 3 and the input cylinder section 31 are arranged. As a result, hot air flows into the drying internal air space 8 from the hot air inlet 22, generating the swirling upward airflow, which in turn creates the negative pressure area 19. The material to be dried is then introduced into the drying internal air space 8 from the input port 32 of the input cylinder section 31.

[0030] As shown in Figures 3, 5, 7, and 8, an air intake port 35 is provided on the peripheral wall portion 5 of the dryer body 2, above the classification means 41, along the tangential direction of the peripheral wall portion 5, and opens into the recovery air area 9. The air intake port 35 is in communication with the intake means via the bag filter. As a result, air is drawn into the recovery air area 9 by the intake means, and this intake generates a swirling airflow. The air intake port 35 is provided on the peripheral wall portion 5 such that the swirling airflow generated in the recovery air area 9 has the same direction of rotation as the swirling upward airflow generated in the drying air area 8.

[0031] As shown in Figure 1, only one classification means 41 is provided in the dryer body 2, and it is positioned near the upper end (top wall portion 6) of the dryer body 2. As a result, the vertical length of the drying air space 8 is longer than that of the recovery air space 9, allowing the material to be dried, which rises due to the swirling updraft, to remain in the drying air space 8 for a relatively longer period of time.

[0032] As shown in Figures 3, 5, 7, and 8, the classification means 41 comprises an inverted cone-shaped classification cover portion 42, a cylindrical classification tube portion 43 protruding downward from the center of the classification cover portion 42, and a classification guide portion 44 disposed inside the classification tube portion 43. Here, the classification cover portion 42 and the classification tube portion 43 are integrally formed, and the outer peripheral edge of the classification cover portion 42 is attached to the peripheral wall portion 5 of the dryer body 2 without any gaps. The classification tube portion 43 is disposed coaxially with the dryer body 2 (peripheral wall portion 5).

[0033] The classification guide section 44 comprises a disc-shaped classification plate section 45 and an inverted conical classification projection 46 projecting downward from the classification plate section 45, with the classification plate section 45 and the classification projection 46 being integrally provided. Here, the classification plate section 45 (and the classification projection 46) are formed with an outer diameter smaller than the inner diameter of the classification cylinder section 43. The classification guide section 44 is attached to the top wall section 6 of the dryer body 2 by a suspension rod 40, so that the classification plate section 45 and the classification projection 46 are arranged coaxially with the classification cylinder section 43 inside the classification cylinder section 43. With this configuration, a narrow, circular annular classification gap 47 is formed between the classification plate section 45 and the inner circumferential surface of the classification cylinder section 43. The drying internal air area 8 and the recovery internal air area 9 are connected only through this classification gap 47.

[0034] The aforementioned conical classification projection 46 has an inclined surface 46a that slopes upward outward along its circumference. Due to this classification projection 46, the cross-sectional area of ​​the inner airspace of the classification cylinder 43 gradually decreases as one moves upward. Therefore, in the inner airspace of the classification cylinder 43, the centrifugal force generated by the swirling updraft and the swirling airflow in the recovery inner airspace 9 can be gradually increased as one moves upward.

[0035] Furthermore, since the classification means 41 of this embodiment has an inverted cone-shaped classification cover portion 42, the cross-sectional area of ​​the lower part of the recovery airspace 9 gradually increases as it moves upward. This makes it possible to suppress pressure loss and airflow turbulence that occur in the recovery airspace 9.

[0036] In this embodiment, the dryer body 2, chamber body 3, and classification means 41 are made of a material with excellent heat resistance and corrosion resistance, specifically stainless steel. This is because corrosion resistance is required since the material to be dried contains a large amount of moisture.

[0037] Next, we will describe the method of drying the object to be dried using the airflow dryer 1 mentioned above. The hot air supply means supplies hot air to the supply air area 15 inside the chamber body 3 via the supply port 14. The hot air supplied to the supply air area 15 directly heats the lower part of the dryer body 2, keeping it at a high temperature, and the heat is transferred from the lower part to the upper part, heating the entire dryer body 2 and keeping it at a high temperature. The hot air supplied to the supply air area 15 then flows into the drying air area 8 of the dryer body 2 from the hot air inlets 22 of each hot air nozzle 21. Here, by adjusting the flow rate of hot air from the hot air supply means, the hot air can flow in from each hot air inlet 22 at a desired flow rate.

[0038] As a result of the continuous inflow of hot air from each hot air inlet 22 into the drying chamber 8, a swirling upward airflow is generated in the drying chamber 8, as shown in Figure 9. As mentioned above, since hot air of approximately the same velocity and flow rate flows in from each hot air inlet 22, a high-speed swirling upward airflow is stably generated. As this swirling upward airflow rises while swirling along the peripheral wall 5 of the dryer body 2, the peripheral wall 5 is heated and maintained at a high temperature. Then, a negative pressure region 19 is generated in the central area of ​​the drying chamber 8 due to the centrifugal force of this swirling upward airflow.

[0039] Furthermore, the hot air supplied to the supply air area 15 flows into the repelling section 25 through the through-hole 16 in the bottom wall 7 of the dryer body 2, heating the repelling section 25 and maintaining it at a high temperature. The repelling section 25 is heated and maintained at a high temperature by heat transfer from the bottom wall 7 and the hot air flowing into the drying internal air area 8.

[0040] On the other hand, the intake means draws air in from the recovery air area 9 of the dryer body 2 through the intake port 35. This intake creates a swirling airflow in the recovery air area 9. As mentioned above, since the swirling airflow in the recovery air area 9 and the swirling updraft airflow in the drying air area 8 are in the same swirling direction, mutual interference and attenuation are suppressed.

[0041] With the dryer body 2 and the drying chamber 8 heated and maintained at a high temperature, the screw feeder is driven, allowing the material to be dried to be introduced into the drying chamber 8 from the inlet 32 ​​of the input cylinder 31. The material introduced into the drying chamber 8 rises while swirling on the swirling updraft, and is dispersed and dried by the hot air of the swirling updraft and the heat received from the dryer body 2. Here, the material to be dried contains moisture and is composed of multiple granular particles, so its size and weight are relatively large. For this reason, the material to be dried swirls violently in the radially outer area (peripheral area 18) of the drying chamber 8 due to the centrifugal force of the swirling updraft, and is dispersed and dried as described above. Furthermore, even if the material to be dried collides with the peripheral wall 5 of the dryer body 2 due to this centrifugal force, as mentioned above, the peripheral wall 5 is maintained at a high temperature, so the material to be dried is prevented from adhering to the peripheral wall 5 and can be put back on the swirling updraft.

[0042] Furthermore, once the material to be dried, introduced through the input port 32, falls to the bottom of the drying chamber 8 due to its weight, it is dried by the lower part of the dryer body 2, which is maintained at a high temperature. Since the material to be dried immediately after being introduced contains a lot of moisture, it can be efficiently dried by the high amount of heat applied from the lower part of the dryer body 2. In addition, because the lower part of the dryer body 2 (the lower part of the peripheral wall 5 and the bottom wall 7) is maintained at a high temperature, the material to be dried is prevented from sticking to it.

[0043] Furthermore, when the material to be dried enters the negative pressure region 19 due to turbulence in the airflow or collision, the influence of the swirling updraft decreases, causing the material to fall out of the negative pressure region 19 due to its own weight. The material that falls out of the negative pressure region 19 collides with the rebound section 25 located on the bottom wall 7 of the dryer body 2 and is repelled outwards. Here, as mentioned above, the rebound section 25 is kept at a high temperature, which suppresses the adhesion of the material to be dried and allows it to be repelled. As a result, the material that falls out of the negative pressure region 19 is repelled by the rebound section 25 and can be put back on the swirling updraft. In addition, as mentioned above, the material that falls out of the negative pressure region 19 can be efficiently dried in the lower part of the dryer body 2, which is kept at a high temperature.

[0044] The effect of dispersing and drying the material to be dried by the swirling updraft also occurs similarly with granular material that is in the process of drying or dispersing (hereinafter referred to as insufficiently dried granular material). The material to be dried introduced into the drying chamber 8 is swirled and risen within the drying chamber 8 by the swirling updraft, dispersing and drying it, and becoming finer granular material compared to the original material. Furthermore, as mentioned above, the dryer body 2 of this embodiment has a structure in which the vertical length of the drying chamber 8 is long, so the residence time during which the material is swirled by the swirling updraft can be made relatively long, allowing for sufficient dispersion and drying, and enabling efficient conversion of the material to be dried into granular material.

[0045] As mentioned above, the granular material that has been sufficiently dried (hereinafter referred to as "dried granular material") has a smaller size and weight, making it less susceptible to centrifugal force from the swirling updraft and easier to move to the central area (negative pressure area 19) of the drying air space 8. In addition, the swirling updraft weakens in the upper part of the drying air space 8, reducing its centrifugal force and causing the granular material to move to the central area. The classification cylinder 43 of the classification means 41 is positioned directly above this central area, and air is drawn in through the classification gap 47 directly below the classification cylinder 43. As a result, the granular material in the upper part of the central area flows into the classification cylinder 43, passes through the classification gap 47, and flows into the recovery air space 9. Here, as mentioned above, the classification gap 47 is narrow, allowing sufficiently dispersed and dried granular material to pass through. The powder and granular material that has flowed into the recovery air area 9 is then discharged from the intake port 35 by the intake of the aforementioned intake means.

[0046] Furthermore, in the drying chamber 8, insufficiently dried powders and granules also rise due to the swirling updraft. Moreover, materials to be dried that have not undergone much drying or dispersion (hereinafter referred to as undried materials) also rise due to the swirling updraft. Because these insufficiently dried powders and granules and undried materials are relatively large in size and weight, they usually remain in the peripheral area 18 of the drying chamber 8 due to the centrifugal force of the swirling updraft, and dispersion and drying proceed. However, in the upper part of the drying chamber 8, the centrifugal force due to the swirling updraft is reduced, which may cause undried materials and insufficiently dried powders and granules to move towards the central area. In addition, in the configuration of this embodiment, since the input cylinder 31 is provided protruding into the drying chamber 8, turbulence is easily generated in the swirling updraft, and this turbulence may cause undried materials and insufficiently dried powders and granules to move towards the central area.

[0047] In the upper part of the drying air space 8, as described above, undried material to be dried or insufficiently dried powders and granules that attempt to move toward the central area are prevented from moving toward the central area by the classification cover portion 42 and classification cylinder portion 43 of the classification means 41, and remain in the peripheral area 18 of the drying air space 8. On the other hand, undried material to be dried or insufficiently dried powders and granules that have moved toward the central area (negative pressure area 19) below the classification cylinder portion 43 may enter the inside of the classification cylinder portion 43 due to the intake of air from the recovery air space 9, as described above, but the classification guide portion 44 and classification gap 47 prevent them from moving toward the recovery air space 9.

[0048] More specifically, undried material to be dried or insufficiently dried powders that enter the negative pressure zone 19 of the drying airspace 8 rise along the central region where the negative pressure is highest, together with dried powders that also enter the negative pressure zone 19. Here, because dried powders are small in size and extremely light, they tend to rise more easily in the outer region (outside the central region) of the negative pressure zone 19 than undried material to be dried or insufficiently dried powders. As a result, when dried powders flow into the inner airspace of the classification cylinder 43 above the negative pressure zone 19, they ride the rising airflow without colliding with the classification protrusions 46, and as described above, pass through the classification gap 47 to reach the recovery airspace 9. On the other hand, undried material to be dried or insufficiently dried powders that enter the negative pressure region 19 are heavier than dried powders, and therefore tend to rise in the central region where the negative pressure is high, colliding with the classification protrusions 46 located directly above the central region and being repelled out of the classification cylinder 43. Even if they move to the classification gap 47 without colliding with the classification protrusions 46, undried material to be dried or insufficiently dried powders are large in size, making it difficult for them to pass through the narrow classification gap 47. They remain inside the classification cylinder 43, collide with the classification protrusions 46, and are repelled out. By repelling the material to be dried or insufficiently dried powders in this way, the time they remain in the drying air space 8 increases, allowing them to be sufficiently dispersed and dried by the swirling rising airflow and the heat of the dryer body 2. Furthermore, in the inner airspace of the classification cylinder 43, the centrifugal force increases upward due to its structure (a structure in which the cross-sectional area decreases towards the top). As a result, the swirling airflow (hot air) in this inner airspace can further disperse and dry the material to be dried and any insufficiently dried granules that have entered this inner airspace. The dried granules can then be moved through the classification gap to the recovery inner airspace 9.

[0049] In this way, the classification means 41 can move the powdered material that has been sufficiently dried in the drying air zone 8 to the recovery air zone 9, and can suppress the movement of undried material to be dried or insufficiently dried powdered material to the recovery air zone 9. Furthermore, since the residence time of the material to be dried or insufficiently dried powdered material in the drying air zone 8 can be extended, they can be sufficiently dispersed and dried. Therefore, with the classification means 41 of this configuration, the dried powdered material can be stably moved to the recovery air zone 9, and the discharge of the material to be dried or insufficiently dried powdered material from the intake port 35 can be prevented.

[0050] As described above, the airflow dryer 1 of this embodiment can stably generate a high-speed swirling upward airflow using hot air in the drying chamber 8 and can maintain the airflow dryer 1 at a high temperature, so that the material to be dried introduced into the drying chamber 8 can be sufficiently dispersed and dried. Furthermore, the classification means 41 described above can stably move the dried powder and granular material to the recovery chamber 9. In addition, it is possible to suppress the movement of the material to be dried and insufficiently dried powder and granular material to the recovery chamber 9, and the time that the material to be dried and insufficiently dried powder and granular material remain in the drying chamber 8 can be extended, so that they can be sufficiently dispersed and dried in the drying chamber 8. In particular, in this embodiment, since the input cylinder 31 is positioned to protrude into the drying internal air area 8, turbulence is easily generated in the swirling upward airflow. This turbulence may cause the material to be dried or insufficiently dried powder to enter the internal air area of ​​the classification cylinder 43. However, as mentioned above, movement into the recovery internal air area 9 can be suppressed, and discharge from the intake port 35 can be prevented.

[0051] Furthermore, since the airflow dryer 1 of this embodiment is equipped with one of the classification means 41 and the classification guide section 44 is attached to the top wall section 6, if the upper part of the airflow dryer 1 is made detachable, internal maintenance can be easily performed by removing the upper part. This also has the excellent advantage of reducing the time and cost required for maintenance work.

[0052] The present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the dimensions and shapes of each part in the embodiments described above can be modified as appropriate.

[0053] In the above-described embodiment, the classification cover is in the shape of an inverted cone, but the shape of the classification cover can be changed as appropriate. For example, it can be a substantially inverted cone with a curved inclined surface or a disc-shaped configuration.

[0054] The embodiment described above has a classification guide section equipped with an inverted conical classification projection, but it is not limited to this configuration. The shape of the classification projection can be appropriately changed as long as it has an inclined surface that slopes downward toward the inside. For example, the classification projection can be hemispherical or polygonal pyramidal. In addition, the embodiment shows the classification guide section attached to the top wall of the dryer body by a suspension rod, but it is not limited to this configuration. For example, it may be attached to the peripheral wall of the dryer body by a beam member or the like.

[0055] The embodiment described above has a configuration in which a conical repelling section is provided on the bottom wall of the dryer body. However, the repelling section is not limited to a cone shape and can have an inclined surface that slopes upward toward the inside. For example, the repelling section can be hemispherical or polygonal pyramidal.

[0056] The above-described embodiment has a configuration in which a vertically elongated rectangular hot air inlet is provided at the bottom of the dryer body, but the shape of the hot air inlet is not limited to this and can be changed as appropriate. For example, it can be made into a vertically elongated triangular shape or a semi-elliptical shape. In addition, the number of hot air inlets (hot air nozzles) can be changed as appropriate.

[0057] In the above-described embodiment, the height at which the hot air nozzle (hot air inlet) is installed at the bottom of the dryer body can be changed as appropriate. For example, as shown in the alternative example in Figure 10, the hot air nozzle 21 can be arranged so that the lower end of the hot air inlet 22 is at the same height as the inner bottom surface (upper surface of the bottom wall portion 7) of the dryer body 2. With this alternative configuration, the hot air immediately flowing in from the hot air inlet 22 hits the material to be dried or insufficiently dried powder or granular material that has fallen to the inner bottom surface (lowest area of ​​the drying internal air space 8) of the dryer body 2, which has the advantage of efficiently drying them. Furthermore, when cleaning the inside of the dryer body 2 with running water, the running water can be drained from the hot air inlet 22 while the dryer body 2 remains upright, which has the advantage of reducing the burden of cleaning.

[0058] The above-described embodiment uses a cylindrical dryer body, but is not limited to this. For example, the external shape can be changed as appropriate, as long as the peripheral wall has a circular inner shape. For example, the external shape may be polygonal. In addition, the inner shape of the peripheral wall is preferably circular in cross-section in order to generate a stable swirling upward airflow.

[0059] In the embodiment described above, the dryer body and classification means are made of stainless steel, but the embodiment is not limited to this, and they may be made of other materials that have heat resistance and corrosion resistance. Furthermore, they may be made of multiple materials. For example, the dryer body may be made of stainless steel with ceramics applied to the inner surface. This configuration improves impact resistance in addition to excellent heat resistance and corrosion resistance by using ceramics. Moreover, since the dryer body in the embodiment is cylindrical, it has the excellent advantage of being easy to apply ceramics to the inner surface. [Explanation of Symbols]

[0060] 1. Airflow dryer 2. Dryer unit 3 Chamber Body 8. Dry Inner Airspace 9. Recovery Airspace 14 supply ports 15 Supply airspace 17. Negative pressure range 22 Hot air inlet 31 Injection cylinder part 32 Inlet 35 Air intake 42 Classification Cover Section 43 Classifying cylinder part 44 Classification Guide Section 46 Classification Convex 46a Slope 47 Classification gap

Claims

1. A dryer body having a sealed drying chamber inside and an air intake port at the top that communicates with a predetermined air intake means, A hot airflow generating means is provided at the bottom of the dryer body and generates a swirling upward airflow in the drying chamber using hot air supplied from a predetermined hot air supply means. Equipped with, In an airflow dryer that dries the material to be dried introduced into the drying airspace by the swirling upward airflow generated in the drying airspace and discharges it from the intake port, A classification cover section is provided inside the dryer body, and divides the interior into a recovery air area drawn in from the intake port and a drying air area below the recovery air area. A cylindrical classification tube is formed in the center of the classification cover portion, projecting downward, and connecting the drying internal air area and the recovery internal air area, A classification guide portion is disposed inside the classification cylinder portion and forms an annular classification gap between itself and the inner circumferential surface of the classification cylinder portion. An airflow dryer characterized by being equipped with the following features.

2. The airflow dryer according to claim 1, characterized in that the classification guide portion is provided with a classification projection having a circumferentially formed inclined surface that slopes inward.

3. The dryer body is substantially cylindrical in shape with both the upper and lower ends closed, The aforementioned hot airflow generating means is Multiple hot air inlets are provided on the lower side surface of the dryer body at predetermined intervals in the circumferential direction of the dryer body, and hot air is introduced into the drying air space in one circumferential direction along the tangential direction of the dryer body. The lower part of the dryer body in which the hot air inlet is formed is enclosed and covered by a chamber body, which is arranged around the lower part to form a supply air area to which hot air is supplied to flow into the hot air inlet, and directly below the dryer body is a chamber body having a supply port to which hot air supplied from the hot air supply means flows into the supply air area. The airflow dryer according to claim 2, characterized in that it is equipped with the following:

4. The dryer body is provided with an input cylinder portion that protrudes into the drying chamber and has an input port at its tip for introducing the material to be dried into the drying chamber. The airflow dryer according to any one of claims 1 to 3, characterized in that the input port of the input cylinder is arranged to face the negative pressure area inside the swirling updraft generated in the drying internal air space.

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