JP2001091156A - Multistage drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely prevent the generation of powder dust compared with this kind of a conventional drying device, to provide a flow passage with structure to be decreased in an influence exercised on a drop port for a substance to be dried without narrowing a flow passage for hot gas, and to increase the size of the whole of the device through planer enlargement without increasing only height. SOLUTION: This drying device is divided into a first chamber having a drying surface 7A; a second chamber having a drying surface 7B; a third chamber having a drying surface 7C; and a fourth chamber having a drying surface 7D. A step being low in a head between present and subsequent drying surfaces and a substance to be dried drop to a subsequent surface are formed at and in the drying surface 7A or 7D. Chambers are disposed in a helical stair-form state from a topmost step to a lowermost step through intercoupling the adjoining steps, and constitution is performed such that the substance to be dried is dropped, in order, from the topmost step to the lowermost step through a step low in a head. Further, the flow passage cross section of an opening part for a hot gas flow passage is enlarged as much as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage drying apparatus, in which the drying surface of each stage is divided into a plurality of drying surfaces, and the drying surfaces are arranged with a step difference therebetween. The present invention relates to a multi-stage drying apparatus provided with a drying surface having a step.

[0002]

2. Description of the Related Art As a conventional multi-stage drying apparatus for drying sludge material or the like by a hot gas, there is one disclosed in Japanese Utility Model Publication No. 5-37194. The configuration of this type of multi-stage drying apparatus will be described with reference to FIGS.

In FIG. 4, reference numeral 1 denotes a drying chamber formed of a castable refractory material, and a drying object inlet 2 is provided at one upper end, and a drying object discharge port 3 is provided at the lower other end. Has been established. A supply device 6 having a supply hopper 4a and a screw conveyor 5a is provided in the drying object introduction port 2.
a, and a discharge chute 4b
And a discharge device 6b having a screw conveyor 5b are connected to each other.

The inside of the drying chamber 1 is divided in parallel at substantially equal intervals in the height direction by a heat-resistant metal plate 8 having an upper surface serving as a drying surface 7. The opposite ends of the metal plate 8 of each stage are cut out to form a communication port 10 that communicates the upper and lower drying surfaces 7. The communication surface 10 allows the drying surface 7 of each stage forming a multi-stage to be connected in series. It is connected to. The drying object introduction port 2 communicates with the uppermost drying surface 7, and the lowermost communication port 10
The drying object discharge port 3 is communicated with. Further, a hot gas inlet 11 and a gas outlet 12 are respectively opened in the side wall portion of the drying chamber 1 which forms one side wall of the drying surface 7 which is one step below the uppermost step and the lowermost step. The flow path of the hot gas in the illustrated example is formed such that the cross-sectional width of the flow path is narrowed to half or less of the width of the drying surface 7 and flows from the upper side to the lower side on the drying surfaces 7 in a plurality of stages. Have been. The flow path of the hot gas may be formed so as to flow from the lower stage to the upper stage, contrary to the example shown in FIG.

[0005] In the figure, reference numeral 13 denotes vertical rotating shafts which are interlocked by gears. A plurality of rotating shafts penetrate the metal plates 8 of the respective stages and are arranged in parallel in the vertical direction. 1
Are rotatably mounted on the upper wall and the lower bottom, respectively. Further, each rotating shaft 13 has a dry surface 7 of each metal plate 8.
A plurality of feed wings 14 arranged so as to be positioned above are attached, and a part of the radius of rotation of the feed wings 14
The distance between the rotating shafts 13 is determined so as to overlap a part of the rotating radius of the rotating shaft 4, and the positioning is performed so that the feed blade 14 does not contact the boss 15 of the adjacent rotating shaft 13.

Further, at least a portion of the inner wall surface of the drying chamber 1 along the radius of rotation of the feed blade 14 is formed in a circular arc shape as an enclosing wall higher than the height of the feed blade 14. A gear box 18 provided with a motor 19 with a drive reduction gear is provided on the drying chamber 1, and the plurality of rotating shafts 13 are alternately arranged adjacent to each other via gears (not shown) provided in the gear box 18. It is designed to rotate in the opposite direction.

The material to be dried containing a large amount of water falls from the supply hopper 4a, and is stirred through the screw conveyor 5a through the material to be dried 2 into the drying chamber 1.
Supplied within.

The material to be dried supplied from the supply device 6a is
It is supplied onto the drying surface 7 of the uppermost metal plate 8 from the drying object introduction port 2 of the drying chamber 1, and the feed blade 14 rotates on the drying surface 7 in the direction of the arrow shown in FIG. The material to be dried is extruded in the rotation direction and the wall direction. Then, it is pushed from the opposite direction by the next feed blade 14 having a part of the radius overlapped, pushed out into the radius of rotation of the third feed blade 14, and sequentially proceeds while being stirred on the drying surface 7 to communicate with the tip. From the object to be dried 20 provided on the end partition plate 23 facing the opening 10, it falls on the drying surface 7 of the next stage by a step difference, and similarly proceeds to the lower drying surface 7.

At this time, the hot gas simultaneously introduced from the hot gas inlet 11 in the upper part of the drying chamber 1 flows from the metal plate 8 at the lowermost stage of the uppermost stage in the same direction as the moving direction of the object to be dried. The material is heated, and the hot gas is discharged from the lower gas outlet 12 via the lowermost stage, accompanied by the evaporated water.

The object to be dried is dried as it proceeds to the lower stage, falls from the communication port 10 of the lowermost metal plate 8 onto the screw conveyor 5b facing the outlet 3 for the object to be dried, and is transferred by the screw conveyor 5b. , Discharge chute 4b
It falls inside and is discharged to the outside of the drying chamber 1.

[0011]

The interval between the drying stages is determined by the flow rate of the hot gas to be heated in consideration of the processing capacity, the passing speed thereof, and the structural reason of the entire drying chamber.
As this kind, the distance between the upper and lower drying stages in the prior art was as large as 700 to 1500 mm.
For this reason, the material to be dried generates dust during falling from the upper stage to the lower stage, mixes with the hot gas, and contaminates the hot gas system equipment to a large degree. However, the multi-stage dryer is still
The major feature is that the degree to which dust is mixed into the hot gas is much smaller than other drying devices, for example, a flow type, a rotary kiln type, etc., which is a great advantage particularly in a process in which hot gas is circulated. there were. In order to further suppress the generation of dust, measures have been taken to provide a chute or the like for preventing the generation of dust in a falling portion of the object to be dried. However, a problem that the object to be dried adheres to the chute for preventing the generation of dust. Also newly occurred.

There is another restriction on the scale of the conventional multi-stage drying apparatus. In other words, it is structurally difficult to increase the size of the drying surface to a certain size due to the thermal expansion of the metal plate that forms the steps. As the gas flow rate also increased, the spacing between the stages had to be increased. Therefore, there has been no method other than increasing the height of the drying device itself.

Further, as shown in FIG. 4 (a), in the conventional structure, the outlet of the object to be dried, which moves to the next drying stage, is also a hot gas transfer passage. The cross-sectional width of the flow path is reduced to half or less of the width of the drying surface 7, and the moving passage between the steps of the hot gas cannot be made large in terms of structure. The dust of the dried material that falls faster and falls down a large step,
There was a problem that it was easy to get on the flow of hot gas.

Accordingly, a first object of the present invention is to provide a multi-stage drying apparatus which significantly suppresses dust generation as compared with a conventional drying apparatus of this type.

A second object of the present invention is to provide a multi-stage drying apparatus having a structure without narrowing the flow path of the hot gas and having such a structure that the flow path has little influence on the outlet of the material to be dried. is there.

A third object of the present invention is not to increase the number of stages but only the height in order to increase the scale.
An object of the present invention is to provide a multi-stage drying apparatus capable of increasing the size of the entire apparatus with a planar spread.

[0017]

In order to achieve the above object, a multi-stage drying apparatus according to the first aspect of the present invention is provided with a large number of stages in a drying chamber in parallel at substantially equal intervals in the height direction. A drying surface, an outer peripheral wall, and a communication port that connects the upper and lower drying surfaces form a flow path of hot gas, and the rotation ranges are arranged in parallel on the drying surface so that the rotation ranges overlap with each other, and in all the stages, A plurality of feed blades are provided at each stage by being attached to a rotating shaft that vertically penetrates the drying surface, and agitated feed by rotating the feed blades on the drying surface and the communication port end of the upper drying surface. In a multi-stage drying apparatus that is dried by contacting with the hot gas while sequentially moving the object to be dried from the uppermost stage to the lowermost stage by dropping the object to be dried from the outlet of the object to be dried provided in the section to the drying surface with a step. , Each of the steps is surrounded by the outer peripheral wall and installed inside. Divided into a plurality of rooms each having the drying surface, wherein the drying surface has a step with a small drop from the top to the next drying surface and the covering to the next drying surface. Providing a dried product outlet, arranging each room in a staircase from the uppermost stage to the lowermost stage by connecting adjacent stages, and passing the dried object from the uppermost stage to the lowermost stage through the small step of the head The structure is such that the hot gas flow path openings are configured to be dropped sequentially, and the flow path cross-sectional area of the opening for the hot gas flow path is made as large as possible.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. The configuration of the drying chamber 1 of the present invention is almost the same as the configuration of the above-described conventional drying chamber 1 except for the drying surface, and thus the description is omitted.

In the first embodiment shown in FIG. 1, the flat drying surface 7 of the conventional one step and one step, for example, the step is reduced by 1 /
It was divided into four dry surfaces divided into four steps in a stepwise manner with a step of 4. That is, as shown in FIG. 1 (a), each step is surrounded by two longitudinal side walls 21a and two transverse end walls 21b, and the inside is formed by one transverse end wall 21b and two longitudinal directions. A drying surface 7A having a drying surface 7A surrounded by a part of the side wall 21a and a first transverse partition wall 24a having an opening for a hot gas flow path to a next stage having substantially the same width as the drying surface width. First and second transverse partition walls 2 each having one chamber, a part of one of the longitudinal side walls 21a, and an opening for a hot gas flow path to a next stage having a width substantially equal to a dry surface width.
4a, 24b, a second chamber having a drying surface 7B surrounded by a central partition wall 22, and the other transverse end wall 21.
b, a part of the two longitudinal side walls 21a and a second transverse partition wall 24b having an opening for a flow path of hot gas to the next stage having a width substantially equal to the width of the dry surface. Dry surface 7
C, a part of the other longitudinal side wall 21a, and first and second traverses each having a hot gas passage opening to the next stage having a width substantially equal to the width of the dry surface. Directional partition wall 24
a, 24b and a fourth chamber having a dry surface 7D surrounded by a central partition wall 22.

On each of the drying surfaces 7A to 7D, two rows of feed blades 14 are provided, and the feed blades 14 are attached to the rotating shaft 13, so that a part of the radius of rotation of the feed blades 14 overlaps that of the adjacent feed blades 14. The distance between the rotating shafts 13 is determined, and the positioning is performed such that the feed blade 14 does not contact the boss 15 of the adjacent rotating shaft 13.

The four dry surfaces 7A to 7D have a phase
Steps are provided to each other, and this step is 1/1 of the conventional step.
It becomes 4. As shown in FIG. 1B, the dry surface 7A₁ Yo
7B₁ Lower, also 7B₁ Than 7C₁ Lower the same
7C₁ More 7D₁ Lower, also 7D₁ One below
Drying surface 7A of split surface of step_Two Lower. In the next step
And likewise dry surface 7A_Two Than 7B_Two And 7B_Two
Than 7C_Two And 7C_Two More 7D_Two And 7D
_Two 7A_Three Lower. Each step is divided into four surfaces
Then dry surface 7A_Two Is just dry surface 7A₁ Of the same 7B
_Two Is 7B₁ Of the same 7C_Two Is 7C₁ Of the same 7D_Two
Is 7D₁ Directly below. Therefore, each dry surface 7A is not
7D is arranged in a stepwise manner by repeating the order.

The feed wing 14 on the drying surface 7 of a certain stage
The object to be dried is rotated in the direction of the arrow shown in FIG. The object to be dried is pushed from the opposite direction by the next feed blade 14 whose radius partially overlaps, is pushed out into the radius of rotation of the third feed blade 14, and is sequentially stirred while being stirred on the drying surface 7. The object to be dried is cut in a part of an end partition plate 23 provided at the end of the drying surface 7 so that the object to be dried does not fall from anywhere as shown in the perspective view of FIG. falling port 20 via a fall in dry surface 7 of the lower one 1, 7A ₁ as shown in FIG. 1 (b) From 7B ₁ ,
7B ₁ From 7C ₁ , Also 7C ₁ From 7D ₁ , Also 7D ₁ From 7A ₂ Are sequentially transferred to. For example, as a representative size of the outlet 20 for the object to be dried, a height of about 150
mm and a width of 100 to 200 mm. On the other hand, the hot gas is sequentially transferred from the upper stage to the lower stage in a space surrounded by the metal plate 8 on the ceiling, the drying surface 7 on the floor, the side wall 21 and the center partition wall 22.

By dividing the drying surface 7 and providing steps to each other, the size of one of the metal plates 8 forming the drying surface 7 can be reduced, and the thermal expansion can be freely performed in at least one direction. did. Also, the drying surface 7 of one stage is
As a result of dividing into two, the step can also be divided into four,
Conventionally, two adjacent drying surfaces, for example, the drying surface 7A,
The step between 7B is reduced to 1/4, so that it is possible to suppress the generation of dust due to the falling of the object to be dried at the object to be dried 20. The hot gas flow path is also provided in a stepwise manner around the drying surface 7, so that, for example, the drying surface 7A ₁ And 7A ₂ Can maintain the same height as before, and the cross-sectional area of the hot gas passage opening is made as large as possible. The flow path cross-sectional area of the gas becomes large, and the flow of the hot gas does not greatly affect the falling of the object to be dried. Further, in order to increase the processing capacity of the multi-stage drying apparatus, not only the height but also the planar spread can be increased, and the entire apparatus can be enlarged while suppressing the height.

A second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, the conventional dry flat surface of each step is divided into two parallel dry surfaces with a 1/2 step difference. That is, FIG.
As shown in (a), each step is surrounded by two longitudinal side walls 21a and two transverse end walls 21b, and the inside is a first chamber having a drying surface 7A with a central partition wall 22 and a drying surface 7A.
And a second chamber having B.

Each of the drying surfaces 7A and 7B has two rows of feed blades 1
4 and a feed wing 14 is attached to the rotating shaft 13 and has the same arrangement as in the first embodiment.

The two drying surfaces 7A and 7B are provided with a step, which is 差 of the conventional step.
As shown in FIG. 3B, the dry surface 7A ₁ Than 7B ₁ Lower, also 7B ₁ Dry surface 7 of the division surface of the next lower stage
A ₂ Lower. In the next stage, the drying surface 7A ₂ Than 7B ₂ Lower, also 7B ₂ 7A ₃ Lower. When each step is divided into two surfaces, the dry surface 7A ₂ Is just dry surface 7A ₁ Of the same 7B ₂ Is 7B ₁ Directly below. Therefore, each of the drying surfaces 7A and 7B is arranged in a zigzag step shape by repeating the order.

The other parts are substantially the same as those described above for the first embodiment.

[0029]

According to the present invention, the generation of dust can be suppressed as compared with the prior art. In addition, the flow path of the hot gas becomes large, and a structure can be provided in which the flow of the hot gas does not affect the falling of the object to be dried. Further, in order to increase the scale, the size of the entire apparatus can be increased.

[Brief description of the drawings]

FIG. 1 (a) is a plan view of a main part of a multi-stage drying apparatus according to a first embodiment of the present invention having a drying surface divided into four steps in a stepwise manner with a conventional 段 step, and FIG. FIG. 1 is a cross-sectional explanatory view taken along the line AA in FIG.

FIG. 2 is a partially cutaway perspective explanatory view of the first embodiment of the present invention.

FIG. 3 (a) is a plan view of a main part of a multi-stage drying apparatus according to a second embodiment of the present invention having a drying surface divided in two in a zigzag stepwise manner with a conventional half-step difference, and (b). Figure 3
FIG.

4 (a) is a partially cutaway plan view of a conventional multi-stage drying apparatus, and FIG. 4 (b) is a cross-sectional explanatory view taken along the line AA in FIG. 4 (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drying room 2 ... Dry material introduction port 3 ... Dry material discharge port 4a ... Supply hopper 4b ... Discharge chute 5a, 5b ... Screw conveyor 6a ... Supply device 6b ... Discharge device 7 ... Drying surface 7A, 7B, 7C, 7D ... Dry surface 8 ... Metal plate 10 ... Communication port 11 ... Heat gas introduction port 12 ... Gas discharge port 13 ... Rotating shaft 14 ... Feed blade 15 ... Boss 18 ... Gear box 19 ... Driving reduction motor 20 ... Dry matter Outlet 21 ... side wall 21a ... longitudinal side wall 21b ... transverse end wall 22 ... center partition wall 23 ... end partition plate 24a ... first transverse partition wall 24b ... second transverse partition wall

Claims (3)

[Claims] 1. A large number of stages are provided in a drying chamber in parallel at substantially equal intervals in the height direction, and heat is generated by a drying surface of each stage, an outer peripheral wall, and a communication port connecting the upper and lower drying surfaces. A gas flow path is formed, and a large number of feed blades are arranged for each stage by being mounted on a rotating shaft that passes through the drying surfaces in parallel so that the rotation ranges overlap with each other on the drying surface and vertically passes through the drying surfaces of all the stages. By setting the agitating feed by rotation of the feed blade on the drying surface and dropping the drying object provided at the end of the communication port of the upper drying surface to the lower drying surface with a step, In a multi-stage drying device for drying by contacting the hot gas while sequentially moving the object to be dried from the uppermost stage to the lowermost stage, each stage is surrounded by the outer peripheral wall, and a partition wall provided inside, Divided into a plurality of rooms each having the drying surface, the drying surface, From the top to the bottom, a step with a small drop between the next drying surface and the above-mentioned object to be dried to the next drying surface is provided, and the adjacent steps are connected to each other, and the stairs are connected from the top to the bottom. Each room is arranged in a shape, and the drying target is sequentially dropped from the uppermost stage to the lowermost stage through the small step, and the flow cross-sectional area of the opening for the hot gas flow path A multi-stage drying apparatus characterized by having as large as possible. 2. The drying step-like surface having a step with a small drop from the top to the bottom is a conventional drying surface divided into four steps in a stepwise manner with a conventional quarter-step. The multi-stage drying apparatus according to claim 1. 3. The drying surface in the form of a step having a small step from the uppermost stage to the lowermost stage is a conventional drying surface which is divided into two parts in a zigzag stepwise manner with a conventional half step. The multistage drying apparatus according to claim 1, wherein