JP2004012015A - Vacuum dryer equipped with freezing mechanism of liquid material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum dryer equipped with a new freezing mechanism of a liquid raw material that can avoid the generation of drying irregularities and contamination and cost increase without causing an increase in the size of an apparatus by performing self-freezing in a state where the liquid raw material is stored on a freezing sheet. <P>SOLUTION: A freezing section 5 has the freezing sheet 51 with a heat insulating material having a small thermal capacity as a material in a spread state, a mechanism for shrinking or deforming the freezing sheet 51 in the spread state, and a nozzle 50 for supplying the liquid raw material L at the upper part of the freezing sheet 51. As a result, the liquid raw material L can be stored on the freezing sheet 51 and at the same time can be self-frozen. Especially, even the liquid raw material L that takes several seconds for self-freezing eliminates the need for providing scattering space required for freezing sprayed liquid droplets M. Additionally, it is not necessary to have a reinforced cooling means at the freezing section 5, thus the apparatus is minimized. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for obtaining a powdery or thin-film solid material by drying a liquid raw material in a frozen state, and in particular, it can prevent the occurrence of contamination and cause quality deterioration. In addition, the present invention relates to a vacuum drier provided with a liquid material freezing mechanism capable of further improving the production efficiency.
[0002]
BACKGROUND OF THE INVENTION
2. Description of the Related Art Conventionally, in the processing of powders such as foods, pharmaceuticals, agricultural chemicals, feeds, and chemicals, as a device for obtaining powders and the like by vacuum-drying a frozen liquid raw material, a freezing chamber and a drying chamber And a dryer equipped with a conveyor (for example, Japanese Patent Publication No. 42-9719) is used in the drying chamber. However, when a liquid material is dried using this type of dryer, there are the following problems.
[0003]
That is, in the apparatus disclosed in Japanese Patent Publication No. 42-9719, as shown in FIG. 9, the nozzle 50 "for spraying the liquid raw material L is provided at the lower part in the freezing part 5" so as to face upward. The object G easily adheres. As a result, the sizes of the sprayed droplets become uneven, and if the attached matter grows and falls into the drying chamber 10 ", uneven drying is caused.
In addition, since the freezing section 5 "is forcibly cooled using a freezing and condensing coil, the freezing section 5" is complicated and large, resulting in an increase in cost and a large installation space.
Furthermore, since the vibration conveyor is located in the drying chamber 10 ", the sanitary property is insufficient, and therefore, it is not suitable for continuously processing different kinds of liquid raw materials.
[0004]
Further, as a device for obtaining powder and granules by vacuum-drying the liquid raw material L in a frozen state, there is a device shown in FIG. This apparatus is provided with a drum cooled by a suitable cooling means in a drying chamber 10 ', sprays a liquid material L onto the surface of the drum to freeze it in a thin film form, and then scrapes the frozen material G with a scraper. Then, vacuum drying is performed in the drying chamber 10 '.
And even in this type of apparatus, since it is necessary to provide a cooling means, there is a problem that the apparatus becomes large, the cost is increased, and furthermore, it is impossible to avoid wear of the scraper and the drum, Contamination is generated by the abrasion powder, and the running cost including maintenance and inspection and replacement of parts is increased.
[0005]
[Technical issues to be solved]
The present invention has been made in view of such a background, and by self-freezing in a state in which a liquid raw material is stored on a frozen sheet, without causing an increase in the size of the apparatus, drying unevenness and the like. It is an object of the present invention to develop a vacuum dryer having a novel liquid material freezing mechanism capable of avoiding generation of contamination and increase in cost.
[0006]
[Means for Solving the Problems]
That is, the vacuum dryer having the function of preventing adhesion of a liquid material according to claim 1 includes a housing having an internal space as a drying chamber, and a vacuum generating device for reducing the pressure in the drying chamber is connected to the housing. In an apparatus for connecting and self-freezing a liquid raw material charged into the drying chamber to obtain a solid material in a granular form or a thin film form by vacuum-drying a frozen material obtained, the liquid raw material is provided in the housing. The freezing section is provided with a frozen section made of a heat insulating material having a small heat capacity in an expanded state, and the frozen sheet in the expanded state is provided. It is provided with a mechanism for expanding and contracting or deforming, and is provided with a nozzle for supplying a liquid material above the frozen sheet.
According to the present invention, the liquid raw material sprayed from the nozzle toward the frozen sheet can be self-frozen while being stored on the frozen sheet. In addition, there is no need to provide a scattering space necessary for the spray droplets to freeze. Further, since there is no need to provide a forced cooling means in the freezing section, the size of the apparatus can be reduced.
[0007]
Further, in addition to the above requirements, the vacuum dryer having the function of preventing adhesion of a liquid material according to claim 2 further comprises, when the frozen sheet is provided in an expanded state, surrounds a rotary shaft provided with blades, and Is provided in a state in which the tip of the liquid material is in contact with the inner surface of the frozen sheet, and is characterized in that a storage portion for the liquid raw material is formed between two adjacent blades.
According to the present invention, by moving the blade by rotating the rotating shaft, the storage portion formed in an extended state between the two adjacent blades can be deformed, so that the expansion and contraction of the frozen sheet and By the action of the blade, the frozen matter can be easily peeled off from the frozen sheet.
[0008]
Furthermore, the vacuum dryer having the function of preventing the adhesion of the liquid material according to claim 3 is, in addition to the requirement according to claim 2, wherein the rotating shaft in the freezing section performs continuous rotation or a fixed angle. Is performed intermittently.
According to this invention, it is possible to prevent the outflow of the liquid raw material by reliably setting the storage portion formed in the frozen sheet to the horizontal state.
[0009]
Furthermore, a vacuum dryer having a function of preventing adhesion of a liquid material according to claim 4 is characterized in that, in addition to the above requirements, the freezing section is provided in a drying chamber.
According to the present invention, since the liquid material sprayed from the nozzle toward the frozen sheet can be self-frozen in the drying chamber while being stored on the frozen sheet, it is particularly necessary to provide a space used only for freezing. Absent. Also, there is no need to provide forced cooling means in the freezing section. Therefore, the size of the device can be reduced. The above object is achieved by using the configuration of the invention described in each of the claims.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a vacuum dryer having a function of freezing a liquid material according to the present invention will be described. First, the configuration of the vacuum dryer D will be described, and then the operation mode of this device will be described. In this embodiment, as the vacuum dryer D, a vacuum vibration dryer is used as an example.
1 and 2 is a vacuum dryer of the present invention, which is mounted on a base B with a housing 1 having an internal space as a drying chamber 10 with an elastic body 2 interposed therebetween. And a vibrator unit 4 for the mount bracket 3 attached to the housing 1. Further, the vacuum dryer D includes a freezing section 5 serving as a freezing mechanism in the drying chamber 10, and further includes, as peripheral devices, a vacuum generator 6 including a condenser, a vacuum pump, and the like, and a heat medium circulating machine 7. The drying chamber 10 is configured to be evacuated and indirectly heated.
The vacuum dryer D configured as described above self-freezes the liquid raw material L (hereinafter, referred to as spray droplet M) sprayed from the nozzle 50 toward the freezing unit 5 in the storage unit 51a in the freezing unit 5. The frozen material G is formed into a thin film-like material, and then the frozen material G is guided into the drying chamber 10, and the casing 1 is vibrated by the vibrator unit 4 so that the frozen material G is dried while flowing. It is intended to obtain a solid material in the form of a body or a thin film.
[0011]
Hereinafter, various members constituting the vacuum dryer D will be described in detail.
First, the base B will be described. As an example, as shown in FIGS. 1 and 2, the base B is formed by appropriately combining steel materials, and four support columns C are erected on the base B. Is done.
The elastic body 2 is, for example, a columnar member formed of an elastic member such as a spring or a vibration-proof rubber.
[0012]
Next, the housing 1 will be described. The housing 1 is a horizontal cylindrical member having an internal space as a drying chamber 10, and four fixed legs 11 are formed on the side circumference of the housing 1. A side plate 12 is provided at the portion so as to be freely opened and closed.
A jacket inner plate 13 is provided inside the casing 1 and the side plate 12, and a heating medium nozzle 14 is further attached. The heating medium nozzle 14 is connected to a heating medium circulator 7 such as hot water.
[0013]
Further, an inlet 15 is formed in a side peripheral portion of the housing 1, an outlet 16 is formed in a side plate 12 located on the opposite side, and an outlet 17 is formed substantially in the center of the housing 1, The vacuum generator 6 is connected to the exhaust port 17 using a flexible pipe F or the like. In addition, a measurement port 18 is formed at an appropriate position of the housing 1, and a temperature sensor, a humidity sensor, and the like are attached to the measurement port 18 and connected to an appropriate control panel (not shown).
[0014]
The outlet 16 is opened and closed by a lid 16a, and the lid 16a approaches and separates from the outlet 16 by operating a handle 16c provided in the duct 16b. Of course, the opening and closing of the lid 16a may be configured so that no manual operation is required by using an appropriate motor or the like.
A drain port 19 is formed in the lower part of the housing 1. In this embodiment, the drying chamber 10 is set on the base B with the outlet 16 side inclined downward by 1 to 2 ° with respect to the horizontal line.
[0015]
The freezing unit 5 is provided below the input port 15 in the housing 1, that is, in the drying chamber 10, and the freezing unit 5 is attached to the side plate 12.
In addition, a nozzle 50 to which a spray nozzle or the like is applied is provided as an example above the freezing section 5, and in this embodiment, the nozzle 50 is installed in the drying chamber 10 so that the ejection port faces downward. did. A pipe is connected to the nozzle 50. The pipe 50 is provided with a raw material tank 50a, a pump 50b, and a valve 50c, so that the liquid raw material L charged into the raw material tank 50a is frozen. It was configured to be able to spray toward. Further, when a fluorine resin is used as the material of the nozzle 50, or when the nozzle 50 is coated with a fluorine resin, etc., it is effective to prevent the liquid material L from adhering.
[0016]
Here, the freezing portion 5 will be described in detail. As shown in FIG. 3, the freezing portion 5 has side plates 52 connected to both side ends of a support frame 53 formed in an inverted U shape in side view, and a bearing provided on the side plate 52. A rotating shaft 55 having blades 56 is axially supported on the shaft 52a. The rotating shaft 55 is rotatably driven by a driving unit 5M including an electric motor, a gear box and the like as appropriate.
Then, the frozen sheet 51 is arranged on the outer surface of the support frame 53, and the frozen sheet 51 is fixed to the support frame 53 by the holding frame 54. The frozen sheet 51 is made of a heat insulating material having a small heat capacity as a material. In this embodiment, a fluorine resin sheet is used as an example, but a sheet of vinyl, nylon, silicon, polyester, or the like may be used. .
An opening 53a and an opening 54a are formed in the support frame 53 and the holding frame 54, respectively, and the outer surface of the frozen sheet 51 is exposed in the drying chamber 10.
[0017]
By configuring the freezing section 5 as described above, the frozen sheet 51 surrounds the rotating shaft 55 provided with the blades 56, and the tip of the blades 56 comes into contact with the inner surface of the frozen sheet 51. Things.
Then, a part of the frozen sheet 51 is in a state of being spread by two adjacent blades 56, and a surface portion of this portion is set as a storage part 51a.
In this embodiment, the number of the blades 56 is four as shown in FIG. 3, but this number can be appropriately selected according to the size of the frozen material G to be obtained. FIG. 5 shows an embodiment in which six blades 56 are used as an example. In this case, since the width of the storage portion 51a is smaller than that in the case where the number of the blades 56 is four, the obtained frozen material G is small.
[0018]
As shown in FIG. 1, a mount bracket 3 is fixed to a lower portion of the outer periphery of the housing 1, and a vibrator unit 4 having an eccentric weight is fixed to the mount bracket 3.
[0019]
The vacuum dryer D of the present invention is configured as described above as an example, and an operation mode of the vacuum dryer D will be described below.
(1) Setting of the apparatus Prior to the operation of the vacuum dryer D, both openings of the housing 1 are closed by the side plate 12 and the outlet 16 is closed by the lid 16a. Further, the number of rotations of the vibrator unit 4 is determined in accordance with the shape, weight, and the like of the frozen material G supplied into the drying chamber 10, and the vibration cycle and the amplitude are set. In this embodiment, the rotation speed is set to 1800 rpm as an example.
Further, the pressure in the drying chamber 10 adjusted by the vacuum generator 6 is set, and the temperature and the flow rate of the heat medium circulated by the heat medium circulator 7 are set.
In addition, the state of the freezing section 5 is set as follows, and as shown in FIG. 3A, by positioning the tips of two adjacent blades 56 in the same horizontal plane, A part of the frozen sheet 51 extended by the blades 56 is kept in a horizontal state. Actually, the horizontal portion of the frozen sheet 51 is bent by its own weight, and the surface portion at this location becomes the storage portion 51a.
[0020]
(2) Self-freezing of the liquid raw material and activating the vacuum generator 6 to make the inside of the drying chamber 10 in a vacuum state, and activating the heat medium circulator 7 to start circulation supply of the heat medium.
Subsequently, the pump 50b is started, and the opening degree of the valve 50c is appropriately adjusted to spray a predetermined amount of the liquid raw material L from the nozzle 50 toward the freezing unit 5. M stays in the storage part 51a of the frozen sheet 51 as shown in FIG. 3 (a), and the temperature decreases with the lapse of time (several seconds) to become a thin-film frozen material G.
[0021]
The use of a flat nozzle or the like as the nozzle 50 makes it possible to uniformly supply the spray droplets M with a narrow width over the entire area of the frozen sheet 51 in the longitudinal direction. This makes it possible to prevent the spray droplet M from adhering to the surface.
[0022]
(3) Peeling of the frozen matter and the spray droplet M are sufficiently frozen when they are peeled from the frozen sheet 51. Specifically, the drive unit 5M is activated to rotate the rotary shaft 55 intermittently or continuously at a constant angle, and in the case of the rotary shaft 55 having four blades 56 shown in FIG. Is rotated by 90 °, and is rotated by 60 ° in the case of the rotating shaft 55 having six blades 56 shown in FIG. At this time, the contact point with the blade 56 on the back surface of the frozen sheet 51 changes, and the storage section 51a is deformed as shown in FIG. 4B, so that the frozen section G is peeled off from the frozen sheet 51. It falls and is supplied into the drying chamber 10.
[0023]
(4) Drying Operation The frozen material G that has reached the inside of the drying chamber 10 is distributed over a wide area in the longitudinal direction of the drying chamber 10 while flowing under the vibration force from the vibration unit 4, and in this state, heat from the heat medium is removed. Received indirectly and sublimated and dried.
The water vapor generated at this time reaches the vacuum generator 6 from the exhaust port 17 and is appropriately discharged to the outside.
[0024]
(5) Discharge operation The discharge port 16 is closed when the moisture value of the frozen material G is eventually detected as a desired value by a temperature sensor or the like or when a preset processing time has elapsed. It is opened and discharged to the outside as a powdery or thin solid material in a desired dry state.
[0025]
(6) Washing operation In the case where different kinds of liquid raw materials L are continuously processed, it is necessary to wash the vacuum dryer D. However, the vacuum dryer D shown in this embodiment is not Has a simple internal structure and can be washed with water. Further, since washing water can be ejected from the nozzle 50 toward the frozen sheet 51 to wash and wash the same, different types of liquid raw materials can be used. L can be easily processed continuously.
[0026]
As described above, according to the vacuum dryer D of the present invention, the spray droplet M sprayed from the nozzle 50 self-freezes in the storage section 51a in the freezing section 5 and has a thickness of about 0.5 to 2 mm. A frozen product G is obtained. After that, since the frozen material G surely falls into the drying chamber 10, the occurrence of uneven drying and contamination can be avoided.
[0027]
[Other embodiments]
Although the present invention is based on the above-described embodiment, the following embodiment can be adopted based on the technical idea of the present invention. First, another embodiment of a mechanism for expanding and contracting or deforming the frozen sheet 51 in the freezing section 5 will be described.
That is, in the basic embodiment described above, the frozen sheet 51 is deformed by the blade 56 provided on the rotating shaft 55, and the contact point with the blade 56 on the back surface of the frozen sheet 51 shifts. Thus, the frozen material G could be reliably separated from the frozen sheet 51.
However, in the case where the releasability is enhanced by coating the frozen sheet 51 with a suitable fluororesin or the like, a simple method of deforming the frozen sheet 51 using a cylinder 58 or an appropriate link mechanism as shown in FIG. Even with such a configuration, the frozen material G can be peeled off.
[0028]
Further, the vacuum dryer D of the present invention includes a casing 1 having an internal space as a drying chamber 10, and a vacuum generator 6 for reducing the pressure in the drying chamber 10 is connected to the casing 1 in a communicating state, This is a device for vacuum-drying a frozen material G obtained by self-freezing the liquid raw material L put into the drying chamber 10 to obtain a powdery solid material. Is provided with a freezing section 5 for freezing the material and obtaining a frozen material. The freezing section 5 includes a freezing sheet 51 made of a heat insulating material having a small heat capacity, and expands or contracts the freezing sheet 51. It is provided with a mechanism for deforming, and is provided with a nozzle 50 for supplying a liquid material above the frozen sheet 51.
Therefore, as for the configuration of the dryer, various types can be adopted as long as it belongs to the category of a so-called vacuum dryer. Hereinafter, description will be made by taking two types of vacuum dryers as examples.
[0029]
[Conical ribbon vacuum dryer]
First, as shown in FIG. 7, the vacuum dryer D can be a so-called conical ribbon vacuum dryer type. In this device, a part or all of the housing 1 is formed in an inverted conical shape, and further, a jacket inner plate 13 is provided inside the housing 1, and a space between the housing 1 and the jacket inner plate 13 is provided. This is an apparatus for drying an object to be processed that has been put into the drying chamber 10 by passing a heating medium through the apparatus.
By closing the upper openings of the housing 1 and the jacket inner plate 13 with the top plate 1b, the internal space of the housing 1 is used as the drying chamber 10. A vacuum generator 6 for reducing pressure is connected.
[0030]
The casing 1 includes a rotating blade 101 attached to a rotating shaft 100. The rotating blade 101 raises an object to be processed along an inner wall of the jacket inner plate 13, and the lifted object is lifted. The object to be dried is promoted while repeatedly dropping the object to the lower portion of the drying chamber 10 again.
Further, a freezing tower 57 is provided in communication with the input port 15 formed in the top plate 1b, a freezing section 5 is provided in the freezing tower 57, and a nozzle 50 is provided above the freezing section 5. Things. Here, the freezing tower 57 is in a state where it is in communication with the drying chamber 10 and is a place where a vacuum is generated by the action of the vacuum generator 6, and thus can be regarded as substantially constituting a part of the drying chamber 10. It is.
[0031]
As described above, even when the present invention is configured as a conical ribbon vacuum dryer type vacuum dryer D, the spray droplet M sprayed from the nozzle 50 self-freezes on the storage part 51a in the freezing sheet 51, It becomes a frozen material G in the form of a thin film. Thereafter, since the frozen material G falls into the drying chamber 10 through the inlet 15, it is possible to avoid drying unevenness and closing the communication part between the freezing tower 57 and the drying chamber 10.
[0032]
[Belt-type continuous vacuum dryer]
Further, as shown in FIG. 8, the vacuum dryer D can be of a so-called belt type continuous vacuum dryer type. The apparatus comprises a cylindrical housing 1 having both ends closed, and a belt conveyor 103 provided along the longitudinal direction of a drying chamber 10 substantially formed in the housing 1. The conveyance process by the belt conveyor 103 includes a steam heating step, a hot water heating step, and a cooling step to dry the object to be processed.
A vacuum generator 6 for reducing the pressure inside the drying chamber 10 is connected so as to communicate with the drying chamber 10, and a freezing tower 57 is provided in communication with the input port 15 in the drying chamber 10. A freezing section 5 is provided in the tower 57, and a nozzle 50 is provided above the freezing section 5. Here, the freezing tower 57 is in a state where it is in communication with the drying chamber 10 and is a place where a vacuum is generated by the action of the vacuum generator 6, and thus can be regarded as substantially constituting a part of the drying chamber 10. It is.
[0033]
Thus, even when the present invention is configured as a vacuum dryer D of a belt type continuous vacuum dryer type, the spray droplets M sprayed from the nozzle 50 self-freeze on the storage section 51a in the freezing sheet 51, It becomes a frozen material G in the form of a thin film. Thereafter, since the frozen material G falls onto the belt conveyor 103 in the drying chamber 10 through the inlet 15, it is possible to avoid uneven drying and closing of the communication section between the freezing tower 57 and the drying chamber 10. Can be.
[0034]
【The invention's effect】
According to the present invention, the liquid raw material L is self-frozen in a state of being stored on the freezing sheet 51, so that drying unevenness and contamination occur without increasing the size of the apparatus, and the cost increases. Can be avoided, and the drying of the liquid raw material L and the production of the granular material can be efficiently performed.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view of a vacuum dryer of the present invention.
FIG. 2 is a right side view and a left side view of the same.
FIG. 3 is a front view and a vertical sectional side view showing a freezing portion when a liquid raw material is stored.
FIG. 4 is a front view and a vertical sectional side view showing a frozen portion when a frozen material is peeled off.
FIG. 5 is a longitudinal sectional side view showing a freezing portion having six blades.
FIG. 6 is a longitudinal sectional side view showing an embodiment using a cylinder as a mechanism for deforming a frozen sheet.
FIG. 7 is a front view showing a conical ribbon vacuum dryer type vacuum dryer shown in another embodiment.
FIG. 8 is a front view showing a belt-type continuous vacuum dryer type vacuum dryer shown in another embodiment.
FIG. 9 is a front view showing the vacuum dryer described in the background of the invention.
FIG. 10 is a front view showing a vacuum dryer described in the background of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 10 Drying room 11 Fixed leg 12 Side plate 13 Jacket inner plate 14 Heat medium nozzle 15 Inlet 16 Outlet 16a Lid 16b Duct 16c Handle 17 Exhaust port 18 Measurement port 19 Drain port 100 Rotary shaft 101 Rotary blade 102 Stirrer blade 103 Belt conveyor 104 Cylinder 104a Arm 105 Heating plate 106 Drop port 2 Elastic body 3 Mount bracket 4 Vibrator unit 5 Freezing section 5M Drive unit 50 Nozzle 50a Raw material tank 50b Pump 50c Valve 51 Freezing sheet 51a Storage section 52 Side plate 52a Bearing 53 Support frame 53a Opening 54 Holding frame 54a Opening 55 Rotating shaft 56 Blade 57 Freezing tower 58 Cylinder 6 Vacuum generator 7 Heat medium circulator 8 Microwave generator 80 Waveguide B Base C Support column D Vacuum dryer F Flexible pipe G Frozen material L Liquid raw material M Spray droplet

Claims (4)

It was provided with a housing having an internal space as a drying chamber, and a vacuum generator for depressurizing the drying chamber was connected to this housing in a communicating state, and the liquid raw material charged into the drying chamber was self-frozen. In an apparatus for obtaining a solid material in the form of a granular material or a thin film by vacuum-drying a frozen material, the housing includes a freezing section for freezing a liquid raw material to obtain a frozen material. The freezing section is provided with a frozen sheet made of a heat insulating material having a small heat capacity in an expanded state and a mechanism for expanding and contracting or deforming the frozen sheet in the expanded state, and a liquid material is provided above the frozen sheet. A vacuum dryer having a freezing mechanism for a liquid material, comprising a nozzle for supply. When the frozen sheet is provided in the expanded state, the frozen sheet surrounds the rotating shaft provided with the blades, and is provided in a state where the tip of the blade is in contact with the inner surface of the frozen sheet, between the two adjacent blades. 2. A vacuum dryer having a freezing mechanism for a liquid raw material according to claim 1, wherein a storage section for the liquid raw material is formed in the vacuum dryer. The vacuum drier provided with a liquid raw material freezing mechanism according to claim 2, wherein the rotating shaft in the freezing section performs continuous rotation or intermittently rotates at a fixed angle. . 4. The vacuum dryer having a liquid raw material freezing mechanism according to claim 1, wherein the freezing section is provided in a drying chamber.

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