JP3836852B2 - Multistage dryer - Google Patents

Description

  The present invention relates to a multi-stage drying apparatus for drying an object to be dried such as a sludge dewatering cake.

Conventionally, this type of multi-stage drying apparatus is provided with a plurality of stages of drying surfaces in the drying chamber, and on the drying surface, the material to be dried is conveyed from one end side to the other end side while stirring. A plurality of rakes are provided. These rakes are provided with a shaft through hole in the center, and a rake shaft serving as a rotatable drive shaft is inserted through the shaft through hole in the upper and lower portions of the drying chamber. The rake is rotated. Here, the rake shaft is inserted into a pot as a bottomed cylindrical shaft insertion member having a rake shaft driving means connected to the upper end portion and an opening portion having a lower end opening formed in the lowermost drying surface. The shaft is rotatably supported in the pot. Further, a heat medium flow passage is formed in the drying chamber so as to face each drying surface. A heat medium such as a hot gas or hot steam for drying the material to be dried passes through the heat medium flow passage. This multi-stage drying apparatus conveys the material to be dried carried into the upper drying surface while stirring it with a rotating rake via a rake shaft, and sequentially transports it to the lower drying surface while drying with a heat medium. (For example, refer to Patent Document 1).
Japanese Utility Model Publication No. 5-37194 (page 1-3, FIG. 1)

  However, in the above-described multistage drying apparatus, dry powder such as dried sludge that has entered from the shaft through-hole of the rake located on the lowermost drying surface penetrates into the pot from the opening and accumulates, and the rake There is a risk of sticking to the lower part of the shaft.

  Since the rake shaft repeatedly expands and contracts in the axial direction due to thermal fluctuations, there is a possibility that the shaft may compete with the dried sludge that is fixed.

  Therefore, by filling the pot with water or a soft mud-like liquid containing water and keeping the dry sludge that leaks through the gap of the rake and enters the pot soft, the A method for preventing lifting is conceivable.

  However, in this case, there is a possibility that the dried sludge and the like that have become soft with moisture are heated by the rake shaft, and the moisture gradually evaporates from the opening to escape to the drying chamber.

  Even if the axial dimension of the pot is sufficiently secured so that the water inside the pot does not reach the evaporation temperature, the water in the pot is sucked up by sludge leaked from the drying chamber over the opening. There is also a fear.

  As a result, dry sludge that has entered the pot becomes a hard lump that dries in the pot, which may increase the rotational load of the rake shaft or lift the rake shaft. In order to prevent an increase in rotational load or lift of the rake shaft, cleaning of the pot must be periodically repeated, and maintenance becomes complicated.

  For this reason, further improvement for preventing the escape of moisture from the pot to the drying chamber is desired.

  This invention is made | formed in view of such a point, and it aims at providing the multistage drying apparatus which can prevent the escape of the water | moisture content from a shaft insertion member.

  The multi-stage drying apparatus according to claim 1 is provided with a drying chamber and a plurality of upper and lower stages in the drying chamber, the drying object is carried into one end side, and the drying object is carried out from the other end side. A surface, a plurality of drive shafts provided along the vertical direction in the drying chamber and rotatable, and disposed on each of the drying surfaces provided on the drive shafts, and rotated by the drive shafts, The materials to be dried carried on the drying surface are conveyed while stirring from one end side to the other end side of these drying surfaces, and the materials to be dried are sequentially carried out from the upper drying surface to the lower drying surface. A plurality of rakes, a heat medium flow passage formed to face each of the drying surfaces, through which a heat medium for drying an object to be dried passes, and an opening that opens to face the drying surface located at the bottom; A fluid filling member containing at least moisture is enclosed inside. And a shaft insertion member that is inserted so that the lower end portion of the drive shaft is rotatable inside, and an oil layer portion that is provided on the top of the filling member in the shaft insertion member and includes at least an oil component in layers. Is provided.

  The filling member sealed in the shaft insertion member is provided by providing an oil layer member containing at least oil in a layer form on the upper part of the filling member sealed in the shaft insertion member in which the lower end portions of the plurality of drive shafts are rotatably inserted. By blocking the gap between the member and the opening with the oil layer portion, it is possible to prevent the moisture of the filling member from escaping from the opening of the shaft insertion member to the drying chamber.

  A multistage drying apparatus according to a second aspect is the multistage drying apparatus according to the first aspect, wherein the oil layer portion is an oil holding member that is formed in a sponge shape and holds oil.

  And it becomes possible to hold | maintain oil content more reliably in a shaft insertion member by hold | maintaining oil with the oil holding member formed in sponge shape.

  The multi-stage drying apparatus according to claim 3 is the multi-stage drying apparatus according to claim 1 or 2, wherein the multi-stage drying apparatus includes a partition plate provided on either the inside or the bottom of the oil layer portion in the shaft insertion member. .

  And it becomes possible by a partition plate to prevent the penetration | invasion of the dried material into a filling member by providing a partition plate in any one of the inside of the oil layer part in a shaft insertion member, or a lower part.

  According to the first aspect of the present invention, by providing the oil layer member containing at least the oil component in a layer form on the upper part of the filling member enclosed in the shaft insertion member in which the lower end portions of the plurality of drive shafts are rotatably inserted. The gap between the filling member sealed in the shaft insertion member and the opening can be blocked by the oil layer portion to prevent the moisture of the filling member from escaping from the opening of the shaft insertion member to the drying chamber.

  According to the second aspect of the present invention, the oil component can be held in the shaft insertion member more reliably by holding the oil component with the oil holding member formed in a sponge shape.

  According to the invention of claim 3, by providing the partition plate in either one of the inside and the lower portion of the oil layer portion in the shaft insertion member, it is possible to prevent the intrusion of the dried material into the filling member by the partition plate. .

  Hereinafter, the structure of the multistage drying apparatus of the 1st Embodiment of this invention is demonstrated with reference to FIG. 1 thru | or FIG.

  5 and 6, reference numeral 1 denotes a drying chamber formed of a castable refractory material. In the drying chamber 1, an object to be dried inlet 2 is formed on one upper end side, and an object to be dried is formed on the other lower end side. A discharge port 3 is formed. The to-be-dried material introduction port 2 is provided with a carry-in device 6 having a hopper 4 and a screw conveyor 5.

  In the drying chamber 1, as shown in FIG. 6, a heat-resistant metal plate 12 whose upper surface is a drying surface 11 is arranged in a plurality of stages in the vertical direction, and these heat-resistant metal plates 12 are Are spaced apart from each other at approximately equal intervals in the direction. Furthermore, the one end side opposite to each other of the drying surfaces 11 of the upper and lower stages is a carry-in side of an object to be dried S such as sludge, and the other end side of the drying surfaces 11 of the upper and lower stages opposite to each other. Is a delivery side of the material to be dried S. That is, the carry-in side of each lower drying surface 11 is arranged below the carry-out side of each upper dry surface 11.

  And the to-be-dried material introduction port 2 is connected to the uppermost drying surface 11, and the to-be-dried material discharge port 3 is connected to the lowermost drying surface 11. That is, the uppermost drying surface 11 is an input stage for the object to be dried S, and the lowermost drying surface 11 is an exhaust stage for the object to be dried S.

  Further, the peripheral edge portion of each drying surface 11 excluding the carry-in side is surrounded by a side wall 15 of the drying chamber 1. Further, as shown in FIG. 5, a shielding wall 17 lower than the side wall 15 is provided on the carry-out side of each drying surface 11, and an object to be dried S is placed on the lower drying surface at the center of the shielding wall 17. An opening 18 is formed to drop 11 into the carry-in side.

  A heating medium introduction port 21 for a heating medium M such as hot gas or hot steam is formed in the side wall 15 of the drying surface 11 that is one step below the uppermost drying surface 11. A heat medium outlet port 22 for the heat medium M is formed in the side wall 15. The heat medium inlet 21 and the heat medium outlet 22 are communicated in a zigzag manner by the heat medium flow passage 23 facing the drying surface 11 from the drying surface 11 of each upper stage to the drying surface 11 of each lower stage. The heat medium M may be circulated from the lower stage to the upper stage.

  Further, in the drying chamber 1, a plurality of shaft insertion holes 24 are formed through the heat-resistant metal plate 12 forming the drying surfaces 11 in the vertical direction, and these shaft insertion holes 24 are rotated as drive shafts. Rake shafts 25 that are shafts are respectively inserted. As shown in FIG. 2, each of the rake shafts 25 is supported by being suspended by being fixed to a suspension member 26 having an upper end portion disposed at the top of the drying chamber 1 by a pin 26a. Furthermore, a plurality of rakes 27 arranged in close contact with each drying surface 11 are attached to each rake shaft 25. And the lower end part of each of these rake shafts 25 is inserted into a pot 28 as a shaft insertion member provided at the lower part of the lowermost drying surface 11 which is the lower part of the drying chamber 1 and is rotatably supported. .

  Here, as shown in FIGS. 2 and 4, the rake 27 includes a cylindrical central shaft portion 32 having a shaft through hole 31 through which the rake shaft 25 is inserted, and the central shaft portion 32. And a pair of arms 33 projecting in the radial direction.

  A guide key 35 as a fitting portion provided from the upper part of the uppermost drying surface 11 to the lowermost drying surface 11 along the axial direction is fitted to the shaft through hole 31 along the axial direction. A key groove 36 is provided as a fitted portion for positioning the rake 27 with respect to the rake shaft 25. The keyway 36 is formed with a buffering gap in consideration of the assembling property of the rake 27 and thermal deformation such as expansion and contraction of the rake shaft 25 due to the temperature in the drying chamber 11. Further, the diameter of the shaft through hole 31 is increased toward the drying surface 11.

  The central shaft portion 32 slightly protrudes upward, and a bearing body 37 is fitted to the lower end portion of the shaft through hole 31. The bearing body 37 is formed in a substantially cylindrical shape having an insertion hole 38 communicating with the shaft through hole 31 and the shaft insertion hole 24 at the center, and is fitted into each shaft insertion hole 24 to It reduces friction during rotation.

  The arm portion 33 is formed to be curved in an arc shape along the circumferential direction of the central shaft portion 32. Further, the respective arm portions 33 protrude in directions opposite to each other with respect to the central axis of the central shaft portion 32. Further, the rakes 27 adjacent to each other are formed so that the curvatures of the central shaft portions 32 are opposite to each other.

  The intervals between the rake shafts 25 are determined such that a part of the rotation radius of the arm portion 33 of each rake 27 overlaps the rotation locus of the arm portion 33 of the rake 27 adjacent to each other, and the rakes 27 are adjacent to each other. It is positioned so as not to interfere with the rake shaft 25.

  Further, as shown in FIGS. 2 and 3, drive gears 41 are respectively attached to the upper end portion of the rake shaft 25, and these drive gears 41 are rotated by a drive motor 42 as a drive source.

  The drive gears 41 that are adjacent to each other are meshed with each other. For this reason, the rake shaft 25 and the rake 27 are configured such that adjacent ones of the rake shaft 25 and the rake 27 are alternately rotated in the opposite directions. These drive gears 41 are fixed integrally with the suspension member 26 via bolts 43 and the like.

  As shown in FIG. 1, each pot 28 is formed of a member such as metal, for example, in a substantially cylindrical shape that is long in the vertical direction, and an opening 45 is formed at the upper end. Here, the opening 45 is fitted to the shaft insertion hole 24 drilled in the heat-resistant metal plate 12 of the lowermost drying surface 11 and is opened facing the drying surface 11, and the upper end portion is connected to the drying surface 11. It is almost the same. Each pot 28 has an inner diameter that is larger than the distance from the central axis of each rake shaft 25 to each guide key 35.

  Further, each pot 28 is inserted into a plurality of heat insulating materials 51 and 52 superposed on the lower part of the lowermost drying surface 11 through the through holes 53 and 54 formed corresponding to the shaft insertion holes 24, and the lower ends thereof. The lower part protrudes downward, and the lower end is fixed to a flat pedestal 55, and is closed by the pedestal 55. Each pot 28 has a sufficient axial dimension so that the water W enclosed inside does not evaporate due to the temperature of the lowermost drying chamber 1.

  Further, in each pot 28, the lower end portion of each rake shaft 25 inserted through the shaft through hole 31 of each rake 27 and the insertion hole 38 of the bearing body 37 is inserted from the opening 45. Further, the lower end portion of the rake shaft 25 is rotatably supported by a shaft steady stop 56 which is a columnar protruding shaft protruding upward from the center portion of the pedestal portion 55, and the upper main surface of the pedestal portion 55 Are spaced apart upward. The pedestal 55 and the tip of the rake shaft 25 are separated by more than the expansion allowance (indicated by the imaginary line) when the rake shaft 25 is extended to the maximum by heat.

  A water supply port 61 is provided in the central area in the vertical direction of each pot 28 below the heat insulating material 52 of each pot 28 toward the central axis. From the water supply port 61, water W as a filling member is introduced from the outside of the pot 28 into each pot 28, and the water W is sealed in the pot 28. In the moisture W, the lower end portion of each rake shaft 25 inserted in each pot 28 is immersed.

  Further, in each pot 28, an oil layer 62 as an oil layer portion and a partition plate 63 are provided corresponding to the position of the water supply port 61, respectively.

  The oil layer 62 is formed in a layer shape so as to close the cross section of the pot 28 with the oil component O, and the upper end portion of the oil layer 62 is located in the vicinity of the lower end portion of the heat insulating material 52 and the moisture W that is in the vicinity of the tip portion of the water supply port 61 is formed. It floats on the top surface. That is, the oil layer 62 is disposed so as to partition between the opening 45 and the moisture W. The oil layer 62 causes the water W enclosed in the pot 28 to be spaced downward from the heat insulating material 52. In other words, the water W sealed in the pot 28 is spaced downward from the opening 45.

  Here, the oil component O has a boiling point higher than the temperature of the lowermost drying chamber 1, for example, 150 ° C., for example, 180 ° C. or more. Therefore, the oil component O does not boil and evaporate due to the temperature of the lowermost drying chamber 1.

  Further, the oil layer 62 has a sufficient thickness so that the dried sludge D as a dried material leaking into the pot 28 does not easily sink into the water W.

  The partition plate 63 is formed in a flat ring shape having a thickness smaller than that of the oil layer 62, and is positioned below the water supply port 61 between the oil layer 62 and the water W sealed in the pot 28. Further, the partition plate 63 is disposed along a horizontal direction substantially orthogonal to the axial direction of the pot 28, and the outer periphery abuts on the inner peripheral surface of the pot 28 with substantially no gap. The partition plate 63 is supported by a plurality of support plates 64 that are curved along the inner periphery of the pot 28. These support plates 64 are formed in a longitudinal shape in the vertical direction from the lower portion of the partition plate 63 to the upper end portion of the pedestal portion 55.

  If the pot 28 is entirely filled with the oil component O, the oil component O will not evaporate, but the leaked dry sludge D gradually increases in the pot 28 and hardens the entire interior of the pot 28. It is desirable that O and coexist in the pot W.

  Further, an inspection hole 65 is provided near the lower end of each pot 28. The inspection hole 65 allows the amount and state of the moisture W enclosed in the pot 28 to be visually confirmed from the outside of each pot 28.

  Further, the side wall 15 and the shielding wall 17 are each curved in an arc shape along the rotation radius of the rake 27.

  Next, the operation of the first embodiment will be described.

  When the material to be dried S is carried from the material to be dried inlet 2 onto the uppermost drying surface 11 by the carry-in device 6, the rake 27 rotating on the drying surface 11 causes the rotation direction and the wall surface direction of the rake 27 to rotate. The material to be dried S is extruded. Furthermore, it is pushed from the opposite direction by the adjacent rake 27 where a part of the radius of the arm portion 33 is overlapped, and further pushed into the rotation radius of the adjacent rake 27, and conveyed while being stirred on the drying surface 11, It is dropped from the drop opening 18 onto the lower drying surface 11 and sequentially carried out.

  At this time, the heat medium M is simultaneously introduced from the heat medium introduction port 21, and the heat medium M is heated from the uppermost drying surface 11 to the lowermost drying surface 11 in the same direction as the conveying direction of the object to be dried S. Moisture is absorbed from the material to be dried S of each drying surface 11 through the medium flow path 23. The moisture-absorbing heat medium M is discharged from the heat medium outlet 22 to the outside of the drying chamber 1.

  The object to be dried S is dried as it is conveyed to the lower drying surface 11, becomes dry sludge D on the lowermost drying surface 11, and is discharged to the outside of the drying chamber 1 through the object to be dried discharge port 3.

  A part of the dried sludge D enters the pot 28 through the opening 45 through a gap between the guide key 35 of the rake shaft 25 and the key groove 36 of the rake 27 and leaks into the oil layer 62. .

  At this time, the partition plate 63 prevents the entire dried sludge D leaked into the oil layer 62 from sinking into the water W enclosed in the pot 28. Further, the dried sludge D slightly leaking into the water W is kept in a soft state by the water W and is prevented from adhering to the rake shaft 25 as a dry solid mass.

  As described above, according to the first embodiment, the oil layer 62 containing the oil component O in layers is provided on the upper part of the water W in the pot 28, so that the water W enclosed in the pot 62 and the opening 45. Is blocked by the oil layer 62, and moisture W can be prevented from escaping from the opening 45 to the drying chamber 1.

  And since the moisture W enclosed in the pot 28 does not escape to the drying chamber 1, the dried sludge D does not become a hard lump in the pot 28.

  As a result, the dry sludge D that has become a solid mass does not increase the rotational load of the rake shaft 25, and does not lift the rake shaft 25 when the rake shaft 25 expands or contracts due to heat, so the reliability of the multistage drying device In addition, it is not necessary to repeatedly clean the inside of the pot 28, and the ease of maintenance is improved.

  Further, by ensuring a sufficient thickness of the oil layer 62, even if the dried sludge D on the lowermost drying surface 11 continues from the drying surface 11 and leaks into the pot 28 from the opening 45, the dried sludge D Since the tip portion hardly reaches the moisture W, the moisture W enclosed in the pot 28 can be prevented from being sucked into the drying chamber 1 by the dried sludge D.

  Moreover, since the water W enclosed in the pot 28 is separated from the drying surface 11 by the oil layer 62, the temperature rise of the water W is suppressed, and the evaporation of the water W can be more reliably prevented.

  Furthermore, by providing the partition plate 63 below the oil layer 62 in the pot 28, it is possible to more reliably prevent the dry sludge D from entering the moisture W sealed in the pot 28.

  In the first embodiment, the partition plate 63 may be provided inside the oil layer 62, that is, at an intermediate position in the vertical direction of the oil layer 62.

  Next, a second embodiment will be described with reference to FIGS. In addition, about the structure and effect | action similar to the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the second embodiment, instead of the oil layer 62 of the first embodiment, a sponge ring 68 as an oil retaining member as an oil layer portion is provided. As shown in FIGS. 7 and 8, the sponge ring 68 is formed of a member such as polyurethane, for example, in the form of a sponge having a large number of holes H and in the shape of a cylindrical ring. Thus, an oil layer is formed above the water W enclosed in each pot 28. The sponge ring 68 abuts on the upper part of the partition plate 63, and the weight is supported by the partition plate 63 and the support plate 64.

  And, by holding the oil component O with the sponge ring 68, the oil component O can be held more securely in the pot 28 than when the oil component O is held only by the oil layer, and the oil component O is replaced. For example, since the entire sponge ring 68 can be replaced, the maintenance becomes easier.

  Moreover, since not only the partition plate 63 but also the sponge ring 68 itself prevents the dried sludge D from sinking into the water W, it is possible to more reliably prevent the dried sludge D from sinking into the water W.

  In the above embodiments, various other members can be used as the filling member as long as it is a fluid containing water.

  In addition, a configuration in which the oil layer 62 and the sponge ring 68 of each of the above embodiments coexist is possible.

It is a longitudinal cross-sectional view which shows the principal part of the multistage drying apparatus of the 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows a part of multistage drying apparatus same as the above. It is a top view which shows a part of multistage drying apparatus same as the above. It is a top view which shows the rake of a multistage drying apparatus same as the above. It is the top view which notched a part which shows a multistage drying apparatus same as the above. It is the side view which notched a part which shows a multistage drying apparatus same as the above. It is a longitudinal cross-sectional view which shows the principal part of the multistage drying apparatus of the 2nd Embodiment of this invention. It is a perspective view which shows the principal part of a multistage drying apparatus same as the above.

Explanation of symbols

1 Drying room
11 Dry surface
23 Heat transfer path
25 Rake shaft as drive shaft
27 Rake
28 Pot as shaft insertion member
45 opening
62 Oil layer as oil layer
63 Partition
68 Sponge ring as oil retaining member as oil layer M Heat medium O Oil S Dry matter W Moisture as filling member

Claims (3)

A drying chamber;
The drying chamber is provided in a plurality of stages above and below, the drying object is carried into one end side, and the drying surface from which the drying object is carried out from the other end side,
A plurality of drive shafts provided in the drying chamber along the vertical direction and rotatable;
These drive shafts are arranged on the respective drying surfaces and are rotated by the drive shafts, and the objects to be dried carried on the drying surfaces are stirred from one end side to the other end side of these drying surfaces. And a plurality of rakes that sequentially convey the object to be dried from the upper drying surface to the lower drying surface;
A heat medium flow passage formed to face each of the drying surfaces and through which a heat medium for drying the material to be dried passes;
Provided with an opening that opens toward the drying surface located at the lowest stage, a fluid filling member containing at least moisture is enclosed inside, and a lower end portion of the drive shaft is rotatable inside A shaft insertion member to be inserted;
A multi-stage drying apparatus comprising: an oil layer portion provided at an upper portion of the filling member in the shaft insertion member and including at least an oil component in a layer form. The multi-stage drying apparatus according to claim 1, wherein the oil layer portion is an oil holding member that is formed in a sponge shape and holds oil. The multi-stage drying apparatus according to claim 1 or 2, further comprising a partition plate provided on either the inside or the bottom of the oil layer portion in the shaft insertion member.

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