JPWO2019235126A1 - Hot air dryer - Google Patents

Abstract

A rotating shaft (3, 4) in which a plurality of paddles (3a, 3b, 4a, 4b) are erected in an inverted spiral shape, a housing (1) containing the rotating shafts (3, 4), and both sides of the housing. It is connected to a lower portion and includes an air supply portion that blows hot air horizontally or diagonally upward into the lower portion of the housing. The rotating shafts (3, 4) are rotated at a non-constant speed to convey the object to be dried while stirring. The hot air blown from the air supply pipes (20b, 21b) of the air supply section to the lower part of the housing flows upward as an air flow between the objects to be dried, and the hot air that becomes the air flow dries the object to be dried.

Description

The present invention relates to a hot air drying device that dries an object to be dried by blowing hot air onto the object to be dried while stirring and transporting the object to be dried.

Conventionally, fine substances containing water, such as steel wet dust, incinerated wet ash, coal powder, food / feed lees, and other sludge / powder, are dried and granulated while stirring using the waste heat of the factory. Is being done.

For example, sludge is conveyed in one direction while being kneaded by rotating two rotating shafts erected so that a plurality of stirring members are arranged in an opposite spiral shape at a non-constant speed, and hot air is blown from above in the process. There is known a hot air drying device that dries an object to be dried by spraying (Patent Document 1 below).

Japanese Unexamined Patent Publication No. 2009-27609

However, in the drying device as described above, since the hot air is blown to the object to be dried from the air supply duct provided at the upper part, the hot air becomes a flow close to a parallel flow passing through the surface of the object to be dried, and the hot air moves downward. There was a problem that the drying efficiency was poor because it did not reach a certain object to be dried sufficiently.

In addition, in a drying device that blows hot air from above, an exhaust duct is provided at the top in order to exhaust the hot air, so it is necessary to separately arrange the air supply duct and the exhaust duct at the top, which complicates the structure. There was a problem of becoming.

The present invention solves such a problem, and an object of the present invention is to provide a hot air drying device capable of downsizing the device and improving the drying efficiency.

The present invention
A hot air drying device that dries the object to be dried by blowing hot air onto the object to be dried while stirring and transporting the object to be dried.
A rotating shaft with multiple stirring members erected in a spiral shape,
The housing that houses the rotating shaft and
An air supply unit that is connected to the lower portions on both sides of the housing and blows hot air horizontally or diagonally upward is provided in the lower portion of the housing.
The hot air blown from the air supply portion to the lower portion of the housing is ventilated between the objects to be dried to be raised as an air flow, and the hot air that has become the air flow is used to dry the object to be dried.

In the present invention, hot air blown into the lower part of the housing from the horizontal direction or diagonally above is ventilated between the objects to be dried to be raised as an air flow, and the hot air that has become the air flow is used to dry the objects to be dried. Therefore, the hot air can be sufficiently distributed between the objects to be dried, and the drying efficiency can be improved.

Further, since the hot air is supplied from the lower portion of the housing and exhausted from the upper portion of the housing, the hot air supply portion and the exhaust portion can be easily separated, and the entire structure can be simplified.

It is a top view which shows the hot air drying apparatus in a state where most of the upper side of a housing is removed. It is a side view of the hot air drying apparatus which showed the state when one of the rotating shafts in a housing is seen from the side. It is sectional drawing along the AA'line of FIG. It is explanatory drawing which showed the drying process which a hot air becomes an air flow and dries an object to be dried. It is sectional drawing corresponding to FIG. 3 which showed the Example which blows hot air from diagonally above to the lower part of a housing. It is a top view corresponding to FIG. 1 which shows the Example which made the rotation axis one axis. It is a side view corresponding to FIG. 2 which shows the Example which made the rotation axis one axis. It is sectional drawing corresponding to FIG. 3 which shows the Example which made the rotation axis one axis.

Hereinafter, the hot air drying apparatus of the present invention will be described in detail based on the examples shown in the drawings. In the present invention, an example will be described in which fine substances containing water, such as steel wet dust, incinerated wet ash, coal powder, food / feed lees, and other sludge / powder, are dried using hot air as objects to be dried. However, the object to be dried is not limited to these exemplified substances, and is also applicable to other substances to be dried.

In FIGS. 1 to 3, reference numeral 1 is a housing of a hot air drying device (hereinafter referred to as a drying device), which is provided horizontally on the frame 2. The housing 1 is made of metal such as stainless steel, and is formed here in an elongated rectangular parallelepiped shape. In the housing 1, two rotating shafts 3 and 4 having the same diameter are erected in parallel with each other along the longitudinal direction thereof. The rotating shafts 3 and 4 are made of metal such as stainless steel and have a circular cross section.

On the upper side of the right end shown in FIG. 2, a hopper (not shown) contains a housing to be dried containing water such as steel wet dust, incinerated wet ash, coal powder, food / feed meal, and other sludge / powder. An input port 1a for charging into 1 is provided. Further, on the lower side of the left end portion, a discharge port 1b for discharging the dried product from the housing 1 onto a conveyor (not shown) is provided.

The right end portions of the rotating shafts 3 and 4 project outward from the housing 1 and are rotatably bearing on the bearing portions 5 and 6, respectively. Further, the left end portions of the rotating shafts 3 and 4 are rotatably supported by bearing portions 7 and 8 attached to the outside of the housing 1.

The right end portions of the rotating shafts 3 and 4 are inserted into the gearbox 12, and the gears 13 and 14 that mesh with each other are fixed to the rotating shafts 3 and 4 in the gearbox 12.

A sprocket 15 is fixed to the outside of the bearing portion 5 of the rotating shaft 3. Further, a motor 18 is mounted on the frame 10, and a sprocket 17 is fixed to the output shaft thereof. A chain 16 is stretched between the sprocket 15 and the sprocket 17.

The rotational driving force in one direction of the motor 18 is transmitted to the rotating shaft 3 via the sprocket 17, the chain 16 and the sprocket 15, the rotating shaft 3 rotates in one direction, and the rotational driving force further causes the gears 13 and 14 to rotate. It is transmitted to the rotating shaft 4 via the rotating shaft 4 and rotates in the opposite direction. The rotation shafts 3 and 4 are rotated at a non-constant speed at a rotation speed ratio of N: N-1 with N as an integer of 2 or more via the gears 13 and 14. For example, N is set to 2 to 6, N is set to 5, and the rotation shafts 3 and 4 are rotated at a rotation speed ratio of 5: 4. As shown in FIGS. 1 and 3, the rotation directions of the rotation shafts 3 and 4 are directions in which they rotate inward with each other when viewed from above.

Paddles 3a and 3b as stirring members are placed on the outer periphery of the rotating shaft 3, and paddles 4a and 4b as stirring members are similarly placed on the outer periphery of the rotating shaft 4 so as to face the paddle of the rotating shaft on the other side. , Each of which is attached at an equal distance in the axial direction and tilted at a predetermined angle with respect to the rotating shaft. In this case, the odd-numbered paddles 3a and 4a from the right in FIG. 1 are feed paddles whose paddle surface sends the object to be dried toward the discharge port 1b when the rotation shafts 3 and 4 rotate. On the other hand, the even-numbered paddles 3b and 4b are return paddles whose paddle surface returns the object to be dried toward the input port 1a.

The feed paddles 3a and 4a and the return paddles 3b and 4b have an angular pitch (90 °: 72 °) equal to the rotation speed ratio (5: 4) of the rotation axes 3 and 4, and the rotation speeds of the rotation axes 3 and 4. They are arranged on the rotation axes 3 and 4 in an anti-spiral shape with a spiral pitch of a ratio (5: 4) and an inverse ratio (1.25: 1).

When the rotating shaft 3 rotates inward in the direction indicated by the arrow, the rotating shaft 4 rotates in the opposite direction. The feed paddles 3a and 4a feed the object to be dried toward the discharge port 1b, the return paddles 3b and 4b return the object to be dried toward the inlet 1a, and the feed paddle and the return paddle are arranged alternately in the axial direction. Therefore, the carrying force of the paddles is offset, but the paddles 3a and 3b of the rotating shaft 3 and the paddles 4a and 4b of the rotating shaft 4 are arranged in an inverted spiral shape with each other. As shown by the arrow, the dried object is conveyed to the left toward the discharge port 1b as seen in FIG.

In this embodiment, in order to dry the object to be dried during the transportation of the object to be dried, hot air is supplied to the left and right sides of the lower portion of the housing 1 into the housing 1 as shown in FIG. Air supply units 20 and 21 for this purpose are provided. The air supply units 20 and 21 are composed of air supply ducts 20a and 21a and air supply pipes 20b and 21b connected to the lower portions of the air supply ducts 20a and 21a and arranged in a plurality of directions in which the rotating shafts 3 and 4 extend. Will be done. The air supply ducts 20a and 21a have a cylindrical shape in which one end is open and the other end is closed, and the rotation shafts 3 and 21a cover almost the entire area of the housing 1 in the extending direction of the rotation shafts 3 and 4. It extends parallel to 4.

On the other hand, the air supply pipes 20b and 21b extend horizontally and laterally in a direction substantially orthogonal to the rotation axes 3 and 4, and a plurality of air supply pipes 20b and 21b are equally spaced in the extension direction of the rotation axes 3 and 4 (8 in the illustrated example). Provided. The other ends 20c and 21c of the air supply pipes 20b and 21b are connected to the lower portion of the housing 1, respectively.

The exhaust heat from the factory becomes hot air and is supplied from the open ends of the air supply ducts 20a and 21a, and the supplied hot air branches laterally from the air supply ducts 20a and 21a and flows to the air supply pipes 20b and 21b. It is blown into the lower portion of the housing 1 via the other ends 20c and 21c. As will be described later, the hot air supplied into the housing 1 becomes hot air for convection heat transfer, circulates between the agitated objects to be dried, and rises as an air flow to dry the objects to be dried. Further, the hot air becomes exhaust heat and is exhausted from the exhaust port 23 provided in the upper part of the housing 1.

As shown in FIG. 3, the drying device has a triangular cross-sectional shape in which the upper side is inclined downward, the lower side is inclined upward, and the remaining side is vertical on the inner left and right surfaces of the housing 1. The walls 24 and 25 are provided to prevent the object to be dried from adhering to the upper side of the inner surface of the housing 1 and remaining. The inclined walls 24 and 25 also have a function of pushing hot air that flows between the objects to be dried and becomes an air flow and rises on the side of the housing inward toward the objects to be dried.

Further, in this embodiment, a damming plate 26 is provided in the vicinity of the discharge port 1b in order to prolong the residence time of the object to be dried and reduce the moisture contained in the object to be dried. The damming plate 26 may be provided inside the housing 1, for example, in the middle portion inside the housing 1, instead of near the discharge port 1b.

Next, the operation of the drying device configured in this way will be described.

When the motor 18 is driven, the rotating shafts 3 and 4 rotate inward at a non-uniform speed at a rotation speed ratio of N: N-1 (5: 4 in this embodiment) as described above.

In this state, the object to be dried is charged from the charging port 1a. The charged object to be dried is agitated by the feed pads 3a and 4a that rotate with the rotation of the rotation shafts 3 and 4, is conveyed toward the discharge port 1b, and is agitated by the return pads 3b and 4b in the opposite direction. Since the paddles are returned to the above, the transport force is offset, but since the paddles are arranged in an inverted spiral shape as a whole, the object to be dried is transported toward the discharge port 1b at a low speed due to the screw effect. Will be done. At this time, each paddle is close to the opposite rotation axis and scrapes off the object to be dried adhering to the paddle, so that a self-cleaning effect can be obtained. In addition, the object to be dried is crushed and granulated by a paddle in the process of being transported.

In this embodiment, hot air such as exhaust heat from the factory is supplied from the air supply units 20 and 21 before or immediately after the material to be dried is charged. The temperature of the hot air is, for example, about 90 ° C to 150 ° C.

The hot air branches from the air supply ducts 20a and 21a and flows horizontally through the air supply pipes 20b and 21b in the lateral direction, and is blown laterally from the other ends 20c and 21c of the air supply pipe into the lower portion of the housing 1. As shown by the arrows in FIG. 4, the hot air blown into the lower portion of the housing 1 flows up from the lower portion of the housing 1 as an air flow between the objects to be dried. In this process, the object to be dried comes into contact with the air flow and is dried.

FIG. 4 schematically illustrates the drying process of the object to be dried 30. In the object to be dried 30, as shown in the upper right, the temperatures of the objects to be dried 30a to 30d on the left and right sides of the housing 1 and the upper part thereof start to rise, and subsequently, as shown in the lower left, the object to be dried 30 The temperature of the whole becomes almost the same, and finally, as shown in the lower right, the temperature becomes close to the supplied hot air, and the object to be dried 30 loses moisture and is dried. In this drying process, the hot air rising to the upper part of the housing 1 is discharged from the exhaust port 23. In addition. FIG. 4 shows that the higher the density of halftone dots, the higher the temperature.

A plurality of air supply pipes 20b and 21b are provided over the entire housing in which paddles are provided in the lower portion of the housing 1, and feed paddles 3a and 4a and return paddles 3b and 4b are alternately provided. Therefore, the object to be dried is conveyed by alternately repeating feeding and returning. Therefore, the drying as shown in FIG. 4 is performed at each place where the paddle is provided, and the entire inside of the housing 1 is covered. It can be seen that the drying is performed efficiently.

Further, the hot air blown laterally from the lower portion of the housing 1 flows upward as an air flow between the agitated objects to be dried, so that the entire object to be dried comes into direct contact with the hot air. , The drying efficiency can be improved. Further, since the object to be dried is returned in the direction of the input port 1a by the return pads 3b and 4b, the time to stay in the housing becomes long, and the object to be dried can be sufficiently dried.

Further, inclined walls 24 and 25 are provided on the inner left and right surfaces of the housing 1, and the inclined walls allow the hot air that flows between the objects to be dried and rises as an air flow to be inclined diagonally upward. Since the portion is pushed inward and the object to be dried is dried again, the drying efficiency can be improved.

In the above-described embodiment, the hot air is blown horizontally from the lateral direction to the lower portion of the housing, but as shown in FIG. 5, it may be blown diagonally upward. In the embodiment shown in FIG. 5, the positions of the other ends 20c and 21c of the air supply pipes 20b and 21b are the same, but the positions of the air supply ducts 20a and 21a are arranged below the positions shown in FIG. Therefore, the air supply pipes 20b and 21b are inclined diagonally upward. Also in this embodiment, the hot air is blown diagonally upward into the lower portion of the housing 1 and flows upward as an air flow between the objects to be agitated. Can be enhanced.

In the first embodiment, two rotating shafts rotating at a non-constant speed are arranged in the housing 1 so that the object to be dried is dried while being stirred and conveyed. However, as shown in FIGS. 6 to 8, The object to be dried may be dried while being stirred and conveyed by one rotating shaft.

The examples shown in FIGS. 6 to 8 are different from the examples of FIGS. 1 to 3 in that the rotating shaft 4 and the stirring member erected therein are removed and the rotating shaft is set to one axis. By the way, the same parts as those in FIGS. 6 to 8 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the second embodiment, when the motor 18 is driven, the rotating shaft 3 rotates, and the object to be dried charged from the charging port 1a is agitated by the feed paddle 3a and the return paddle 3b as the rotating shaft 3 rotates. , It is conveyed toward the discharge port 1b. In this process, the hot air supplied from the air supply ducts 20a and 21a to the air supply pipes 20b and 21b flows horizontally in the lateral direction and is blown laterally from the other ends 20c and 21c of the air supply pipe to the lower portion of the housing 1. Is done. The hot air blown into the lower part of the housing 1 flows up from the lower part of the housing 1 as an air flow between the objects to be dried, and the object to be dried comes into contact with the air flow and is dried.

Also in the second embodiment, the hot air blown laterally from the lower portion of the housing 1 flows upward as an air flow between the objects to be dried, so that the drying efficiency can be improved. In the second embodiment as well, as shown in FIG. 5, the air supply pipes 20b and 21b may be arranged so as to be inclined diagonally upward so that hot air may be blown diagonally upward from the lower portion of the housing 1. ..

In the paddles arranged on the rotation axis in Examples 1 and 2, the feed paddle and the return paddle are arranged alternately, but the number of feed paddles is increased, and the feed paddle, the feed paddle, and the return paddle are arranged in this order. It may be arranged repeatedly to increase the transport force in the feed direction. Further, all the paddles of the rotating shafts 3 and 4 can be used as feed paddles. Further, although the stirring member was a paddle in Examples 1 and 2, a stirring member composed of a rod may be used instead.

1 Housing 1a Input port 1b Discharge port 3, 4 Rotating shaft 3a, 4a Feed paddle 3b, 4b Return paddle 5, 6, 7, 8 Bearing part 12 Gearbox 13, 14 Gear 15, 17 Sprocket 16 Chain 18 Motor 20, 21 Air supply section 20a, 21a Air supply duct 20b, 21b Air supply pipe 23 Exhaust port 26 Dam stop plate

Claims (9)

A hot air drying device that dries the object to be dried by blowing hot air onto the object to be dried while stirring and transporting the object to be dried.
A rotating shaft with multiple stirring members erected in a spiral shape,
The housing that houses the rotating shaft and
An air supply unit that is connected to the lower portions on both sides of the housing and blows hot air horizontally or diagonally upward is provided in the lower portion of the housing.
Hot air drying is characterized in that hot air blown from the air supply portion to the lower portion of the housing is ventilated between the objects to be dried to be raised as an air flow, and the object to be dried is dried by the hot air that has become the air flow. apparatus. The air supply unit is composed of an air supply duct and a plurality of air supply pipes connected to the air supply duct and arranged in a direction in which a rotation axis extends. The hot air drying device according to claim 1, wherein the hot air drying device is supplied into the body. The hot air drying device according to claim 1 or 2, wherein the hot air is discharged from an exhaust port provided in an upper portion of the housing. With the rotating shaft as the first rotating shaft, a second rotating shaft in which a plurality of stirring members are erected in an inverse spiral shape with the stirring member of the first rotating shaft is provided in parallel with the first rotating shaft. The feature is that the second rotating shaft is rotated at a non-constant speed, and the stirring members of the first and second rotating shafts are arranged at an angular pitch having the same ratio as the rotation speed ratio of the first and second rotating shafts. The hot air drying apparatus according to any one of claims 1 to 3. The invention according to any one of claims 1 to 4, wherein the stirring member is configured as a feed paddle having a paddle surface inclined with respect to the axis of the rotation shaft so as to feed the object to be dried in one direction. The hot air drying device described. The hot air drying according to claim 5, wherein in addition to the stirring member configured as the feed paddle, a stirring member configured as a return paddle for returning the object to be dried in the reverse direction is erected on the rotating shaft. apparatus. The hot air drying apparatus according to claim 6, wherein a stirring member configured as a feed paddle and a stirring member configured as a return paddle are alternately erected on a rotating shaft. Any one of claims 1 to 7, wherein a slanted wall is provided on the inner left and right surfaces of the housing to push hot air that becomes a ventilation flow and rises on the side of the housing inward toward the object to be dried. The hot air drying device described in. The hot air according to any one of claims 1 to 8, wherein a damming plate for increasing the residence time of the object to be dried and reducing the moisture contained in the object to be dried is provided inside the housing. Drying device.

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