JP4326433B2 - Drying equipment - Google Patents

Description

  The present invention relates to a drying device that removes moisture by drying a paste-like material containing a large amount of moisture.

  Foods such as okara, sludge, raw garbage and the like that are rich in moisture are preferably dried to prevent spoilage. As a drying method, there are means such as drying by hot air heating and vacuum drying.

  In the case of drying by simple heating, direct heating using an electric heater as a heating device locally increases the temperature. Therefore, as countermeasures against deterioration of the object to be dried due to heat, countermeasures such as thickening the inner wall material of the treatment tank or heating with water vapor or a warm bath are taken.

  In the case of drying by heating, if the target object is food, especially if it has a lot of protein, such as okara, the quality will deteriorate and the product value will be lost if it is overheated and burnt. It is necessary to perform more efficient drying at a temperature at which quality does not deteriorate.

  Thus, as a method for eliminating waste of energy during drying, a vacuum drying apparatus utilizing the fact that the boiling point is lowered by reducing the pressure has been proposed. However, when vacuum drying is performed, the moisture in the material to be dried freezes due to adiabatic expansion by vacuum processing, and the drying efficiency may be significantly reduced. Has been proposed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  The drying apparatus by vacuum heating evacuates the drying treatment tank with a decompression apparatus, heats the treatment tank, and stirs the material to be dried in the treatment tank to perform drying. The heating temperature at this time needs to be a temperature that does not cause thermal degradation of the object to be dried. By reducing the pressure, if the boiling point is lowered and the heat of vaporization is sufficiently supplied, evaporation can be performed at a low temperature and drying can be performed quickly.

  When vacuum drying is used, if a vacuum pump is used as a decompression device, the odor of the object to be dried is released to the atmosphere, and if released as it causes environmental pollution, it is discharged to the atmosphere through a filter. Measures are required. In particular, when a food is dried, if a protein is liberated from an object to be dried, a bad odor is likely to be generated. Therefore, treatment with an exhaust gas filter or the like is indispensable.

  Therefore, as disclosed in Patent Document 1 and Patent Document 2, a decompression device using a water flow ejector has been proposed. In the case of a decompression device using a water flow ejector, odor is absorbed by water, so that no bad odor is released to the outside, and useful substances can be recovered.

JP-A-9-318255 JP 2002-31478 A JP 2003-90679 A

  By the way, in vacuum, since heat transfer efficiency is poor and there is no convection, heating to an object to be dried is only heat transfer from a vacuum vessel. A conventional drying apparatus using a heating vacuum rotates a vacuum processing tank itself, or provides a stirring honey in the processing tank to stir the material to be dried in the processing tank. The contact area is increased to improve heat transfer efficiency, and the temperature gradient is reduced.

  However, simply rotating the treatment tank or stirring the stirring object to stir the material to be dried does not provide uniform stirring, and is not sufficient to achieve a uniform temperature gradient. Need to be dried.

  Therefore, the object of the present invention is to efficiently transfer heat to the object to be dried even in a vacuum, to uniformly heat the entire object to be dried, to achieve a uniform temperature gradient, and in a short time, It is providing the drying apparatus which can dry.

  The drying apparatus of the present invention is airtight and has a cylindrical treatment tank in which the longitudinal direction of the cylinder is arranged in the vertical direction during the drying process, a heating unit that heats the outer periphery of the treatment tank, and a decompression device that depressurizes the inside of the treatment tank With.

  And this invention equips the inside of a processing tank with a screw pump part, a some division wall, and the braid | blade rotation mechanism provided with the stirring blade.

  The treatment tank is preferably formed by inclining the bottom of the cylinder in a funnel shape. By forming the lower part in a funnel shape, the material to be dried tends to accumulate at the bottom of the treatment tank. It is preferable that a processing tank arrange | positions a support shaft in the direction orthogonal to the longitudinal direction of a cylinder, and supports a processing tank rotatably. In this way, by supporting the treatment tank so as to be rotatable, the treatment tank can be tilted when cleaning the inside of the treatment tank, so that the work becomes easy and the drying is efficiently performed during the drying process. The treatment tank can be arranged so that the longitudinal direction of the treatment tank faces in the vertical direction.

  A heating part enables it to heat the whole outer peripheral surface of a processing tank. For example, a sealed vessel covering the outer peripheral surface and the bottom of the processing tank is arranged around the processing tank so that a predetermined gap is formed between the outer peripheral surface of the processing tank and a heating tank is formed. A hot part can be formed by accumulating warm water. In this case, the outer surface of the treatment tank is warmed by the hot water stored in the heating tank, and the object to be dried inside the treatment tank is warmed. Rather than heating the treatment tank locally with an electric heater, the heating unit preferably warms the entire treatment tank uniformly using warm water in order to prevent quality deterioration due to overheating of the object to be dried.

  As the decompression device, an aspirator, a tank in which water is stored, a pump, and a cooling device are preferably connected by piping. By connecting a pipe communicating with the inside of the processing tank to the aspirator, the processing tank is depressurized.

  The screw pump unit is disposed so as to extend in the cylindrical axis direction at the center of the processing tank, and transports to-be-dried material collected at the bottom of the processing tank during the drying process to the upper part of the processing tank and discharges it from the upper discharge port.

  The screw pump unit includes a rotary shaft, a screw integrally formed on the outer peripheral surface of the rotary shaft in a spiral manner, a pump motor that drives the rotary shaft and is arranged outside the processing tank, and a screw together with the rotary shaft. It is preferable to have a configuration including a cylindrical storage portion to be stored.

  In this case, one end portion of the rotating shaft is exposed to the outside from the bottom of the processing tank and connected to a pump motor, and the other end portion is rotatably supported by a support member at an upper portion in the processing tank. Furthermore, the lower end part used as the process tank bottom side edge part of a cylindrical storage part forms the intake port for taking in the to-be-dried material collected in the outer periphery of a cylindrical storage part in a cylindrical storage part. Moreover, the upper end part used as the process tank upper part edge part of a cylindrical storage part forms the discharge port for discharging the to-be-dried material conveyed with the screw to the outer side of a cylindrical storage part.

  A partition wall is arrange | positioned below the upper discharge port of a screw pump part, and partitions and divides the space formed between a screw pump part and the inner surface of a processing tank into a cylinder axial direction. A partition wall is arrange | positioned in the predetermined position using the member for fixing on the inner surface of a processing tank. For example, the partition wall is formed of a disk whose diameter is substantially equal to the inner diameter of the processing tank, and a ring-shaped support frame having the same inner diameter and outer diameter as the processing tank is fixed to the inner surface of the processing tank, and the partition wall is defined on the support frame. Put it on the wall to prevent it from rotating.

  Each partition wall has a dropping hole for dropping an object to be dried. It is preferable that one drop hole is provided in each partition wall and that the drop holes in adjacent partition walls are not overlapped in the axial direction. By shifting the position of the dropping hole in this way, it is possible to prevent the material to be dried from dropping from the upper dropping hole through the lower dropping hole to the bottom of the processing tank.

  Furthermore, the partition wall is preferably formed of a material having high thermal conductivity, for example, a metal material such as iron, particularly titanium or stainless steel for food drying. When the partition wall is formed of a material having high thermal conductivity, the outer peripheral end surface of the partition wall is brought into contact with the inner surface of the treatment tank. The partition wall is heated by the inner wall of the processing tank heated by the heating unit to warm the entire partition wall, and the material to be dried that has fallen on the partition wall is warmed by the partition wall.

  The blade rotation mechanism includes stirring blades that extend radially with respect to the cylindrical axis of the processing tank and are rotatably arranged around the cylindrical axis on the upper surface side of each partition wall. The stirring blade of the blade rotation mechanism includes a leveling blade for leveling the material to be dried falling on the partition wall to a predetermined thickness, and a hole for dropping by scraping the material to be dried falling on the partition wall shape. It is preferable to provide a scraping blade that is dropped from the head.

  The stirring blade is preferably formed of an elastically deformable synthetic resin, for example, a fluororesin. In particular, when the scraping blade is such an elastically deformable member, it can be scraped well by being deformed according to the amount of the object to be dried on the partition wall.

  The material to be dried that has fallen on the partition wall falls from the dropping hole while being stirred on each partition wall by the stirring blade. When the stirring blade is composed of a leveling blade and a scraping blade, the material to be dried is leveled over the partition wall by the leveling blade, and the contact rate of the material to be dried with the partition wall is increased. Increase the drying efficiency. The material to be dried, which has been warmed up on the partition wall, is scraped off by a scraping blade and falls from the dropping hole.

  In the case where the leveling blade and the scraping blade are provided, the scraping blade is arranged with a predetermined angle away from the leveling blade in the rotation direction. The leveling blade and the scraping blade are preferably 180 degrees apart. By arranging each blade in this way, the material to be dried can be leveled with a leveling blade and heated for a predetermined time, and then scraped with a scraping blade, so that drying can be performed efficiently.

  Further, the blade rotating mechanism uses a cylindrical storage portion of the screw pump portion, and this cylindrical storage portion, a stirring blade fixed to the outer periphery of the cylindrical storage portion so as to extend in the radial direction, and a cylinder that rotates the cylindrical storage portion. It is preferable to have a configuration including a storage unit rotating motor.

  The cylindrical housing portion is rotationally driven by a motor provided separately from the pump motor of the screw pump portion. Specifically, a bearing and a seal portion are provided between the cylindrical storage portion and the rotary shaft at a position below the screw formation position on the rotary shaft of the screw pump portion so that the cylindrical storage portion can be rotated with respect to the rotary shaft. To do. Then, for example, a bevel gear is provided on the outer periphery of the lower end of the cylindrical storage portion and the tip of the drive shaft of the cylindrical storage portion rotation motor, and the cylindrical storage portion is rotated by driving the cylindrical storage portion rotation motor via the bevel gear. be able to.

  Due to the rotation of the cylindrical storage portion, the stirring blade circulates on the partition wall around the cylindrical storage portion axis. Due to the revolving motion of the stirring blade, the material to be dried on the partition wall is stirred, and a part of the material to be dried falls from the dropping hole.

  Next, a drying method using the drying apparatus of the present invention will be described. First, a predetermined amount of material to be dried containing a large amount of moisture is put into the treatment tank. The treatment tank is preheated. While the treatment tank is heated by the heating unit, the screw pump unit is driven and the stirring blade is also rotated. After the temperature of the material to be dried in the treatment tank rises to a predetermined temperature, the inside of the treatment tank is depressurized to a predetermined pressure by a decompression device.

  When the treatment tank is heated by the heating unit, the temperature inside the treatment tank rises and the object to be dried is heated. The heating temperature by the heating unit is a temperature at which the quality of the material to be dried does not deteriorate. At this time, the to-be-dried material collected at the bottom of the processing tank is transported to the top of the processing tank by the screw pump unit and discharged onto the uppermost partition wall. The discharged material to be dried falls on the lower partition wall from the dropping hole provided in the partition wall while being stirred by the stirring blade. The material to be dried collected on the lower partition wall is also stirred by the stirring blade and falls from the dropping hole. This operation is repeated by the number of partition walls, and the material to be dried accumulates again at the bottom of the processing tank.

  And after heating and heating the processing tank by the heating unit for a predetermined time while repeating such conveyance and stirring, the inside of the processing tank is depressurized using a decompression device. In the present invention, for example, in the decompression process, the pressure is reduced to 5 to 80 Torr (670 to 10670 Pa) using an aspirator. The water evaporated from the material to be dried is liquefied by the driving water in the aspirator. Unnecessary substances taken into the circulating water of the decompression device are removed using a filter. In addition, the water-soluble protein of the material to be dried is recovered together with the circulating water.

  Since the object to be dried may freeze due to adiabatic expansion only by the decompression process, in the present invention, in order to prevent the object to be dried from being frozen, the object to be dried in the treatment tank is 70 ° C. by the heating unit. The treatment tank is heated to be heated below.

  In this way, the object to be dried is efficiently heated by repeatedly transporting the object to be dried by the screw pump unit and stirring for each partition wall while heating the object to be dried and reducing the pressure in the treatment tank. Dried.

  Heating by the heating unit may be performed until the drying process is completed, or after heating for a predetermined time, heating may be stopped and only decompression may be performed.

In the present invention, since the object to be dried comes into contact with the plurality of heated partition walls while being stirred by the stirring blade, the contact area to be heated is increased, so that the heat transfer efficiency of the object to be dried is improved. Thus, the temperature can be made uniform. As a result, since the surface area of the object to be dried is increased, the evaporation area is increased and the drying time can be shortened.
In particular, by using a leveling blade and a scraping blade as the agitation blade, the material to be dried can be leveled over the entire partition wall, so that the contact area of the material to be dried with the partition wall is maximized. Furthermore, the heat transfer efficiency of the material to be dried is improved. Since the partition wall is sufficiently heated by forming the partition wall with a material having high thermal conductivity, the heat transfer efficiency of the object to be dried can be further improved.

  Furthermore, the drying apparatus of the present invention can be made inexpensive and compact, and can dry a material to be dried at an optimum temperature with high efficiency, so that drying can be performed in a shorter time than before. As a result, food residues such as squeezed straw and extracted straw are not discarded as industrial waste, but food straw that can be reused as food and feed can be provided at low cost.

  An embodiment of a drying apparatus of the present invention will be described with reference to the drawings. As shown in FIG. 1, the drying device according to the present embodiment includes a processing tank 1, a heating unit 2, and a decompression device 3, and further includes a screw pump unit 4 and a plurality of partition walls 5 in the processing tank 1. And a blade rotation mechanism 6.

  The processing tank 1 includes a lid 11, a cylindrical tube body 12, and a bottom 13 made of a donut-shaped disk, and the lid 11 can be opened and closed with respect to the tube body 12. The cylinder body 12 has a flange portion formed in the upper opening portion and a lower portion formed in a funnel shape. By forming the lower part of the cylindrical part body 12 in a funnel shape, it is easy to collect the material to be dried at the bottom of the treatment tank 1.

  The lid portion 11 has a flange portion formed at the opening edge portion, a connection portion to which the communication pipe 36 of the decompression device 3 is connected, and an input port 11a through which an object to be dried is input. In the present embodiment, a sealing member is interposed between the lid portion 11 and the flange portion of the cylindrical portion main body 12, and the lid portion 11 and the cylindrical portion main body 12 are connected to each other by a fixing member such as a bolt in an airtight manner. Yes.

  The lower end of the cylindrical part body 12 is fixed to the bottom part 13 by welding. The lower end of the tubular body 12 is fixed at the intermediate position in the radial direction of the bottom 13. The bottom 13 also serves as the bottom of the heating tank 21 described later. A first bearing member 71 having a ring-shaped seal member 71a and a ball bearing 71b at the center is fixed to the bottom surface side of the bottom portion 13.

  The heating unit 2 includes a cylindrical body 22 disposed around the cylindrical body 12 and a bottom 13 of the processing tank 1 so that a predetermined gap is formed between the outer peripheral surface of the processing tank 1 and the heating tank 21. And the hot water is stored in the heating tank 21.

  The cylindrical body 22 is substantially similar to the cylindrical body 12 having a size that covers the cylindrical body 12, and the upper end is also inclined inward in the radial direction. The upper end of the cylindrical body 22 is fixed to the outer surface of the processing tank 1 by welding, and the lower end is fixed to the bottom 13 by welding to make the inside of the heating tank 21 airtight.

  Although not shown, the heating tank 21 has an inlet and an outlet for injecting or discharging hot water from the outside, and the inlet and the outlet are connected to the boiler by a pipe. The piping is removable from the inlet and outlet. In this embodiment, a pump is provided in the middle of the pipe so that hot water heated by the boiler is injected into the heating tank 21 from the inlet, discharged from the outlet, and returned to the boiler again. It has become. In order to keep the temperature of the hot water in the heating tank 21 constant, the hot water is circulated, and when the heating is stopped, the heating in the boiler and the pump are stopped.

  The heating unit 2 heats the entire outer peripheral surface of the cylindrical body 12 with warm water stored in the heating tank 21. The outer surface of the processing tank 1 is warmed by the heating unit 2 so as to warm the material to be dried inside the processing tank 1.

  A support shaft 81 is fixed to the outer surface of the heating tank 21 in a direction perpendicular to the longitudinal direction of the tube portion main body 12 at an intermediate position in the longitudinal direction of the tube portion main body 12. By supporting the support shaft 81 on the support table 82 so as to be rotatable, the processing tank 1 is rotatably supported on the support table 82 together with the heating tank 21.

  By supporting the processing tank 1 rotatably on the support base 82, when removing the lid 11 from the cylindrical body 12 and cleaning the inside of the processing tank, the processing tank 1 is inclined to facilitate the work, At the time of the drying treatment, the treatment tank is disposed so that the longitudinal direction thereof is directed in the vertical direction.

  The decompression device 3 is used to decompress the inside of the processing tank 1. The decompression device 3 is configured by connecting an aspirator 31, a tank 32 in which water is stored, a pump 33, and a cooling device 34 by a pipe 35. A communication pipe 36 communicating with the inside of the treatment tank is connected to the aspirator 31, and when water flows through the aspirator 31, air in the treatment tank 1 is sucked into the aspirator 31 from the communication pipe 36, Depressurization is performed. A filter 37 is provided in the tank 32. An exhaust pipe is branched in the communication pipe 36, and a valve is provided between the exhaust pipes.

  The screw pump unit 4 includes a rotary shaft 41, a screw 42 integrally formed in a spiral manner on the outer peripheral surface of the rotary shaft 41, a pump motor that drives the rotary shaft 41 and is disposed outside the processing tank 1. A first motor 43 and a cylindrical housing portion 44 in which the screw 42 is housed together with the rotating shaft 41.

  The rotating shaft 41 of the screw pump unit 4 is disposed so as to extend in the cylindrical axis direction of the cylindrical body 12 at the center of the processing tank 1. As shown in FIG. 3, the lower end portion of the rotating shaft 41 is brought out from the bottom portion of the processing tank 1 and connected to the first motor 43. Further, the lower portion of the rotating shaft 41 is rotatably supported by a second bearing member 72 fixed to the cylindrical housing portion 44, and the upper end portion of the rotating shaft 41 is an upper portion in the processing tank 1 as shown in FIG. It is rotatably supported by a support member 9 fixed to the head. As shown in FIGS. 1 and 3, the first motor 43 is supported by the processing tank 1 via an L-shaped member fixed to the first bearing member 71.

  As shown in FIG. 3, the cylindrical housing portion 44 of the screw pump portion 4 has a lower end opening closed with a donut-shaped disk member 45, and a rotating shaft 41 is rotatably supported on the bottom surface side of the disk member 45. A second bearing member 72 is fixed. The second bearing member 72 includes a ring-shaped seal member 72a, a ball bearing 72b, and a cylindrical portion 72c through which the rotary shaft 41 is inserted at the center in the radial direction. The second bearing member 72 rotatably supports the rotating shaft 41 by a seal member 72a and a ball bearing 72b, and the cylindrical portion 72c is rotatably supported by the seal member 71a and the ball bearing 71b of the first bearing member 71.

  Further, the cylindrical housing portion 44 is driven to rotate by a second motor 61 serving as a cylindrical housing portion rotation motor provided separately from the first motor 43 via the second bearing member 72. A first bevel gear 62 is formed on the outer periphery of the lower end of the cylindrical portion of the second bearing member 72. Also, a second bevel gear 63 is provided at the tip of the drive shaft of the second motor 61, and the second bearing is driven by the second motor 61 via the first bevel gear 62 and the second bevel gear 63. By rotating the member 72, the cylindrical housing portion 44 is rotated. The second motor 61 is supported by a mounting member fixed to the first bearing member 71 as shown in FIGS. 1 and 3.

  In addition, the cylindrical storage portion 44 forms a take-in port 44a for taking in the material to be dried collected in the outer periphery of the cylindrical storage portion 44 into the cylindrical storage portion at the lower end portion arranged at the bottom of the processing tank. . A discharge port 44b is formed at the upper end of the cylindrical storage portion 44 for discharging the material to be dried conveyed by the screw 42 to the outside of the cylindrical storage portion 44. The cylindrical storage portion 44 is supported by the support member 9. The upper end of the is rotatably supported.

  The support member 9 that supports the cylindrical housing portion 44 includes a ring-shaped first bearing portion 91, a ring-shaped second bearing portion 92, a ring-shaped fixed frame portion 93, and a plurality of rod-shaped connecting members 94. Composed. The 1st bearing part 91 supports the rotating shaft 41 rotatably. The 2nd bearing part 92 supports the cylindrical storage part 44 rotatably. The fixed frame portion 93 is fixed to the inner peripheral surface of the cylindrical portion main body 12 of the processing tank 1 with bolts. The rod-shaped connecting member 94 connects the first bearing portion 91, the second bearing portion 92, and the fixed frame portion 93, and extends radially from the center of the support member.

  In the present embodiment, the screw 42 is driven by rotating the rotating shaft 41, and the material to be dried accumulated in the bottom of the processing tank 1 is transferred from the intake 44a of the cylindrical storage portion 44 into the cylindrical storage portion 44. It is taken in and transported to the upper part of the processing tank, and the material to be dried is discharged from the upper discharge port 44b of the cylindrical storage part 44.

  The partition wall 5 is disposed below the upper discharge port 44b of the screw pump unit 4, and a plurality of spaces formed between the cylindrical storage unit 44 of the screw pump unit 4 and the inner surface of the processing tank 1 are arranged in the cylindrical axis direction. Divide into compartments. In the present embodiment, three partition walls 5 are provided.

  As shown in FIG. 2, the partition wall 5 is composed of a donut-shaped disk member and is supported so as not to rotate by a fixing frame member 10 fixed to the inner surface of the processing tank 1.

  The partition wall 5 has an outer diameter that is slightly smaller than the inner diameter of the processing tank so that the outer peripheral surface is in contact with the inner surface of the processing tank, and the inner diameter is a size that allows the cylindrical storage portion 44 to be inserted to prevent rotation on the bottom surface side. The projection 51 for use is formed.

  The fixing frame member 10 is configured by connecting ring frames having different diameters with radially extending rod-like frames. The outer ring frame has an outer diameter equal to the outer diameter of the partition wall 5, and the inner ring frame has an inner diameter defined by the partition wall. Is equal to the inner diameter of

  Then, the outer ring frame of the fixing frame member 10 is fixed to the inner surface of the processing tank with a bolt, and the partition wall 5 is placed on the fixing frame member 10. At this time, the projection 51 of the partition wall 5 is brought into contact with the rod-shaped frame of the fixing frame member 10 to prevent the partition wall 5 from rotating.

  Each partition wall 5 is formed with a drop hole 52 for dropping an object to be dried. The dropping hole 52 has a rectangular shape extending radially outward from the center side, and is provided at one location on each partition wall 5. Further, when the partition wall 5 is placed on the fixing frame member 10, the partition walls 5 are arranged so that the drop holes 52 of the adjacent partition walls do not overlap in the axial direction. By shifting the position of the drop hole 52 in this way, the material to be dried is prevented from dropping from the upper drop hole 52 directly through the lower drop hole 52 to the bottom of the treatment tank. Can do.

  Further, the partition wall 5 and the fixing frame member 10 are formed of a metal having high thermal conductivity, such as titanium or stainless steel. In the present embodiment, the outer peripheral surface of the partition wall 5 is brought into contact with the inner surface of the processing tank 1, and a part of the bottom surface of the partition wall 5 is brought into contact with the inner surface of the processing tank 1 through the fixing frame member 10. Therefore, the partition wall 5 is easy to transmit the heat of the inner wall of the treatment tank 1 heated by the heating unit 2, and the entire partition wall is sufficiently warmed, and the material to be dried falling on the partition wall is warmed by the partition wall.

  The blade rotation mechanism 6 includes a cylindrical housing portion 44, a second motor 61, a second bearing member 72, a first bevel gear 62, a second bevel gear 63, and a stirring blade 64.

  One end of the stirring blade 64 is fixed to the outer peripheral surface of the cylindrical storage portion 44 so as to be disposed on the upper surface side of each partition wall 5, and the stirring blade 64 extends radially with respect to the axial center of the cylindrical storage portion 44. Has been placed. The stirring blade 64 rotates on the partition wall 5 by the rotation of the cylindrical housing portion 44.

  The stirring blade 64 is provided with a leveling blade 64a for leveling the material to be dried that has fallen on the partition wall to a predetermined thickness, and the material to be dried that has fallen in the shape of the partition wall is scraped from the dropping hole 52. And a scraping blade 64b to be dropped.

  In the leveling blade 64a and the scraping blade 64b, the blade portions are made of a synthetic resin that can be elastically deformed, for example, a fluororesin, and these blades are fixed to a rod-like support member. The fixing position of the support member to the cylindrical storage portion 44 is the same for both blades, but the cutting edge of the scraping blade 64b is always in contact with the partition wall 5, and the cutting edge of the leveling blade 64a is the upper surface of the partition wall 5. The size of the blade is changed so that it is away from Accordingly, a predetermined gap is formed from the upper surface of the partition wall 5 to the cutting edge of the leveling blade 64a, and when the leveling blade 64a rotates, the material to be dried is leveled by the leveling blade 64a. .

  Further, the scraping blade 64b is in contact with the partition wall 5 in a state where the blade is elastically deformed, and even if the amount of the material to be dried on the partition wall fluctuates, the scraped material is scraped well. be able to.

  In this embodiment, the material to be dried that has fallen on the partition wall 5 is leveled over the entire partition wall by the leveling blade 64a, and the contact rate of the material to be dried with the partition wall 5 is increased. The drying efficiency is improved. Then, the material to be dried that has been leveled and heated on the partition wall is dropped from the dropping hole 52 while being scraped off by the scraping blade 64b.

  The leveling blade 64a and the scraping blade 64b are arranged so as to be 180 degrees apart in the rotational direction. By arranging the blades in this way, the material to be dried can be leveled by the leveling blade 64a and heated for a predetermined time, and then scraped by the scraping blade 64b, so that drying can be performed efficiently.

  In the present embodiment, as shown in FIG. 2, the rotating shaft 41 and the cylindrical storage portion 44 of the screw pump portion 4 rotate in opposite directions.

  In this embodiment, each part of the screw pump unit 4, the partition wall 5, the stirring blade 64, the second bearing member 72, and the support member 9 are detachable from the processing tank 1, and after the drying process is completed. These parts can be removed from the treatment tank 1 and cleaned.

  Next, a drying method using the drying apparatus of the present invention will be described. First, the processing tank 1 was tilted and the lid part 11 was removed from the cylindrical part body 12, and the parts of the screw pump part 4, the partition wall 5, the fixing frame member 10 and the like were taken out for cleaning in the processing tank 1. Install the parts.

  Then, the lid portion 11 is attached to the cylindrical portion main body 12, and the processing tank 1 is disposed so that the axial direction is directed in the vertical direction. Hot water is stored in the heating tank 21 and the processing tank 1 is heated by the heating unit 2. A predetermined amount of material to be dried containing a large amount of moisture is charged into the processing tank 1 from the charging port 11a. At this time, while feeding the material to be dried, the cylindrical housing portion 44 is rotationally driven to rotate the stirring blade 64, and the material to be dried accumulated on the uppermost partition wall 5 is sequentially dropped onto the lower partition wall. Then, the material to be dried is accumulated at the bottom of the treatment tank 1.

  When the operation of charging the object to be dried is completed, the inlet 11a is closed, the processing tank 1 is sealed, the heating tank 2 is heated and the screw pump unit 4 is driven and the cylindrical storage unit 44 is heated. And the stirring blade 64 is also rotated. The material to be dried collected at the bottom of the processing tank 1 is conveyed to the upper part of the processing tank 1 by the screw pump unit 4 and discharged from the discharge port onto the uppermost partition wall. Then, the material to be dried is leveled on the partition wall by the leveling blade 64a, and the material to be dried is heated by the partition wall. Thereafter, the material to be dried is scraped off by the scraping blade 64b and falls onto the lower partition wall 5 from the drop hole 52. The object to be dried falls to the bottom of the processing tank 1 by the rotating operation of the stirring blade. In this manner, the upward conveyance by the screw pump unit 4 and the leveling and dropping operations by the stirring blade 64 are repeated.

  Since the drying object may freeze due to adiabatic expansion only by the decompression process, in the present embodiment, in order to prevent the object to be dried, first, before the decompression, the heating unit The processing tank is heated so that the material to be dried in the processing tank is heated to 70 ° C. or less by 2.

  Specifically, in the drying process using only the heating unit 2, the processing tank 1 is heated in advance before the material to be dried is put into the processing tank 1. Next, the object to be dried put in the treatment tank 1 is heated for 30 minutes, for example. At this time, heating by the heating unit 2 of the processing tank 1 (for example, a temperature of hot water of 80 ° C.) is performed so that the temperature of the object to be dried in the processing tank 1 becomes 70 ° C. The heating temperature of the treatment tank by the heating unit is a temperature at which the quality of the material to be dried does not deteriorate and a temperature at which freezing due to reduced pressure does not occur. At the stage of this heat treatment, the material to be dried is uniformly heated as a whole.

  Next, the heating of the heating unit 2 is stopped, and while the pressure in the processing tank 1 is reduced by the pressure reducing device 3, the conveyance by the screw pump unit 4 and the leveling and dropping operation by the stirring blade 64 are performed. . In the present embodiment, the decompression process is performed using an aspirator so that the pressure is reduced to 5 to 80 Torr (670 to 670 Pa). Moisture evaporated from the material to be dried is liquefied by the driving water in the aspirator, and unnecessary matter taken into the circulating water of the decompression device is removed by the filter 37. In addition, the water-soluble protein of the material to be dried is recovered together with the circulating water. In this embodiment, the entire drying time from the start of heating of the object to be dried is set to 2 to 3 hours.

  In this way, by heating the object to be dried and reducing the pressure inside the treatment tank, the object to be dried is repeatedly transported by the screw pump unit 4 and stirred for each partition wall 5 by repeating the process. It can be dried efficiently.

  The vacuum drying apparatus of the present invention is suitable for drying pasty food materials such as okara.

It is the whole block diagram which showed the partial cross section of the drying apparatus concerning embodiment of this invention. It is a cross-sectional view of the processing tank of the drying apparatus concerning embodiment of this invention. It is an expanded sectional view of the lower part of the processing tank in FIG.

Explanation of symbols

1 Treatment tank
11 Cover 11a Slot 12 Tube body 13 Bottom
2 Heating unit 21 Heating tank 22 Tubular body
3 Pressure reducing device
31 Aspirator 32 Tank 33 Pump 34 Cooling device
35 Piping 36 Communication piping 37 Filter
4 Screw pump section
41 Rotating shaft 42 Screw 43 First motor (motor for pump)
44 Cylindrical storage 44a Intake port 44b Discharge port 45 Disc member
5 Compartment wall 51 Projection 52 Drop hole
6 Blade rotation mechanism
61 2nd motor (motor for rotating cylindrical housing)
62 1st bevel gear 63 2nd bevel gear
64 Agitation blade 64a Leveling blade 64b Scraping blade
71 First bearing member 71a Seal member 71b Ball bearing
72 Second bearing member 72a Seal member 72b Ball bearing
72c Tube
81 Support shaft 82 Support base
9 Support member
91 First bearing portion 92 Second bearing portion 93 Fixed frame portion 94 Connecting member
10 Fixing frame member

Claims (5)

A drying apparatus comprising a cylindrical processing tank in which the longitudinal direction of the cylinder is vertically arranged during a drying process, a heating unit that heats the outer periphery of the processing tank with hot water, and a decompression device that decompresses the inside of the processing tank In
Inside the treatment tank,
A screw pump section that extends in the cylindrical axis direction at the center of the processing tank, conveys the material to be dried at the bottom of the processing tank to the top of the processing tank at the time of the drying process, and discharges it from the upper discharge port;
A partition wall that is arranged below the upper discharge port of the screw pump part and partitions the space formed between the screw pump part and the inner surface of the treatment tank into a plurality of partitions in the cylindrical axis direction,
A blade rotation mechanism comprising a stirring blade extending radially with respect to the cylindrical axis on the upper surface side of each partition wall and arranged to be rotatable about the cylindrical axis ;
A fixing frame member that supports the partition wall inside the processing tank;
The screw pump part is
A rotation axis;
A screw integrally formed on the outer peripheral surface of the rotary shaft in a spiral shape;
A motor for the pump that drives the rotating shaft and is arranged outside the processing tank;
A screw is housed together with the rotating shaft, and includes a take-in port for taking in the material to be dried at the lower end portion and a cylindrical housing portion having a discharge port for discharging the material to be dried at the upper end portion,
Each partition wall provided so as holes in the partition walls fall hole adjacent for dropping the material to be dried does not overlap in the axial direction,
The fixing frame member is
An outer ring frame fixed to the inner surface of the treatment tank;
An inner ring frame arranged outside the cylindrical storage portion;
A drying apparatus comprising: a rod-shaped frame connecting both ring frames .   The drying device according to claim 1, wherein the partition wall dropping hole is provided at one location on each partition wall so that the holes of the adjacent partition walls do not overlap in the axial direction.   The drying apparatus according to claim 1 or 2, wherein the partition wall is formed of a material having high thermal conductivity, and the outer peripheral end surface of the partition wall is in contact with the inner surface of the treatment tank. The stirring blade of the blade rotation mechanism
A leveling blade for leveling the material to be dried that has fallen on the partition wall to a predetermined thickness;
The drying apparatus according to any one of claims 1 to 3, further comprising a scraping blade that scrapes an object to be dried falling on the partition wall and drops it from the dropping hole. The blade rotation mechanism is
A cylindrical housing part of the screw pump part;
An agitation blade fixed to the outer periphery of the cylindrical storage portion so as to extend in the radial direction;
The drying apparatus according to any one of claims 1 to 4, further comprising: a cylindrical housing rotating motor that rotates the cylindrical housing.

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